JP6903791B2 - Friction transmission belt - Google Patents

Description

The present invention relates to a friction transmission belt.

It has been proposed that various materials are contained in the compressed rubber layer of the friction transmission belt for the purpose of reducing the generation of noise during belt 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 the rubber composition forming the compressed rubber layer of the V-ribbed belt contains the aramid powder for the purpose of reducing noise.

Japanese Unexamined Patent Publication No. 2010-196743 International Publication No. 2009/093465

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

An object of the present invention is to obtain a very high noise generation reducing 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 constituting a pulley contact portion on the inner peripheral side of the belt, and the rubber layer contains a crosslinked rubber component, a layered silicate, and an aramid powder. It is made of a material, and carbon black as a reinforcing material is blended in the rubber composition, and the content of the reinforcing material with respect to 100 parts by mass of the rubber component in the rubber composition is that 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 when the belt is exposed to water, as shown in Examples described later. In addition to being able to obtain a very high effect of reducing the generation of abnormal noise, it is also possible to obtain excellent durability.

It is a perspective view of the V ribbed belt which concerns on Embodiment 1. FIG. It is sectional drawing for one V-rib of the V-ribbed belt which concerns on Embodiment 1. FIG. It is a vertical cross-sectional view of a belt molding die. It is a vertical cross-sectional enlarged view of a part of a belt molding die. It is 1st explanatory drawing of the manufacturing method of the V ribbed belt which concerns on Embodiment 1. FIG. It is a 2nd explanatory drawing of the manufacturing method of the V ribbed belt which concerns on Embodiment 1. FIG. It is a 3rd explanatory drawing of the manufacturing method of the V ribbed belt which concerns on Embodiment 1. FIG. It is a 4th explanatory drawing of the manufacturing method of the V ribbed belt which concerns on Embodiment 1. FIG. It is a figure which shows the pulley layout of the auxiliary drive belt transmission device of an automobile. It is a perspective view of the V ribbed belt which concerns on Embodiment 2. FIG. It is sectional drawing for one V-rib of the V-ribbed belt which concerns on Embodiment 2. FIG. It is 1st explanatory drawing of the manufacturing method of the V ribbed belt which concerns on Embodiment 2. FIG. It is a 2nd explanatory drawing of the manufacturing method of the V ribbed belt which concerns on Embodiment 2. FIG. It is a perspective view of the V ribbed belt which concerns on Embodiment 3. FIG. It is sectional drawing for one V-rib of the V-ribbed belt which concerns on Embodiment 3. FIG. It is 1st explanatory drawing of the manufacturing method of the V ribbed belt which concerns on Embodiment 3. It is a 2nd explanatory drawing of the manufacturing method of the V ribbed belt which concerns on Embodiment 3. It is a 3rd explanatory drawing of the manufacturing method of the V ribbed belt which concerns on Embodiment 3. It is a perspective view of the low edge type V belt which concerns on other embodiment. 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 evaluation of abnormal noise at the time of water in water. 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 an endless belt used for, for example, 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 is composed of a triple layer consisting of a compression rubber layer 11 forming a pulley contact portion on the inner peripheral side of the belt, an adhesive rubber layer 12 in the middle, and a back rubber layer 13 on the outer peripheral side of the belt. The ribbed belt main 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 the middle portion of the adhesive rubber layer 12 of the V-ribbed belt main body 10 in the thickness direction. The thickness of the compressed rubber layer 11 is, for example, 1.0 to 3.6 mm, the thickness of the adhesive rubber layer 12 is, for example, 1.0 to 2.5 mm, and the thickness of the back surface rubber layer 13 is, for example, 0.4. It is ~ 0.8 mm. In addition, the back surface reinforcing cloth may be provided instead of the back surface rubber layer 13.

The compression rubber layer 11 is provided so that a plurality of V-ribs 15 hang down on the inner peripheral side of the belt. The plurality of V-ribs 15 are formed in ridges having a substantially inverted triangular cross section extending in the belt length direction, and are arranged side by side 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 obtained by heating and pressurizing an uncrosslinked rubber composition in which various compounding agents containing a layered silicate and an aramid powder are mixed with a rubber component and kneaded to crosslink the rubber component. It is formed. Therefore, the rubber composition forming the compressed rubber layer 11 contains a crosslinked rubber component and various compounding agents including a layered silicate and an aramid powder.

Examples of the rubber component of the rubber composition forming the compressed rubber layer 11 include ethylene-propylene-dienter polymer (hereinafter referred to as “EPDM”), ethylene-propylene copolymer (EPM), ethylene-butene copolymer (EDM), and the like. Examples thereof include 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. The rubber component is preferably used by blending one or more of these, preferably ethylene-α-olefin elastomer, and more preferably EPDM.

When the rubber component of the rubber composition forming the compressed rubber layer 11 is an ethylene-α-olefin elastomer, the ethylene content is preferably 50% by mass or more, more preferably 55% by mass or more, still more preferably 57% by mass. It is more preferably 70% by mass or less, more preferably 60% by mass or less, still 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, 1,4-hexadiene and the like. Of these, ethylidene norbornene 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 etilidennobornene, the ENB content is preferably 0.5% by mass or more, more preferably 4% by mass. As mentioned above, it is more preferably 4.4% by mass or more, preferably 10% by mass or less, more preferably 6% by mass or less, still more preferably 4.6% by mass or less.

The Mooney viscosity of the ethylene-α-olefin elastomer in the rubber component of the rubber composition forming the compressed rubber layer 11 at 125 ° C. is preferably 15 ML _{1 + 4} (125 ° C.) or higher, more preferably 18 ML _{1 + 4} (125 ° C.) or higher. , also preferably _75ML 1 + 4 (125 ℃) or less, more preferably _70ML 1 + 4 (125 ℃) or less, more preferably _20ML 1 + 4 (125 ℃) or less. Mooney viscosity is measured based on JIS K6300.

Examples of the layered silicate include smectite, vermulite, and kaolin. Examples of the smectite tribe include montmorillonite, biderite, saponite, hectorite and the like. Examples of the vermulite family include 38 octahedral vermulite and 28 octahedral vermulite. Examples of the kaolin tribe include kaolinite, dikite, halloysite, lizardite, amesite, chrysotile and the like. As the layered silicate, it is preferable to use one or more of these, it is more preferable to use the smectite group, and it is further preferable to use montmorillonite.

The rubber composition forming the compressed rubber layer 11 preferably contains fine flake-shaped layered silicates in a dispersed manner. The average particle size of the flake-shaped 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 flake-shaped layered silicate is determined by the number average of 50 to 100 maximum outer diameters measured in the 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, and further preferably 10 parts by mass with respect to 100 parts by mass of the rubber component. It is 5 parts by mass or more, preferably 100 parts by mass or less, more preferably 50 parts by mass or less, and further preferably 25 parts by mass or less.

The "aramid powder" in the present application is a powdery to granular aromatic polyamide, which is derived from aramid fibers such as short fibers obtained by secondary processing of so-called aramid fibers or those obtained by further tertiary processing to form fibrils. Does not include. Examples of the aromatic polyamide constituting the aramid powder include para-aromatic polyamide and meta-aromatic polyamide, and among these, the former para-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 teraphthalamide. Among these, the former polyparaphenylene terephthalamide Is preferable. The rubber composition forming the compressed rubber layer 11 preferably contains the aramid powder in a dispersed manner. 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 size of the aramid powder is determined by the number average of 50 to 100 maximum outer diameters measured in the 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. It is more than parts, preferably 50 parts by mass or less, more preferably 30 parts by mass or less, still more preferably 15 parts by mass or less.

In the rubber composition forming the compressed rubber layer 11, the content of the layered silicate (A) with respect 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 generation reducing effect and excellent durability. It is preferably more than the amount (B). The ratio (A / B) of the content of the layered silicate (A) to the content (B) of the aramid powder with respect 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, and 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 of the layered silicate (A) and the content of the aramid powder (B) is preferably 5 with respect to 100 parts by mass of the rubber component. It is more than parts by mass, more preferably 10 parts by mass or more, preferably 100 parts by mass or less, more preferably 70 parts by mass or less, still more preferably 55 parts by mass or less.

Examples of the compounding agent include reinforcing materials such as carbon black, vulcanization aids, cross-linking agents, and vulcanization accelerators.

As the reinforcing material, in carbon black, for example, channel black; furnace black such as SAF, ISAF, N-339, HAF, N-351, MAF, FEF, SRF, GPF, ECF, N-234; FT, MT, etc. Thermal black; acetylene black and the like. Silica can also be mentioned as a reinforcing material. 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. It is less than a part.

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

The content (C) of the reinforcing material (carbon black) with respect to 100 parts by mass of the rubber component is larger than the content (B) of the aramid powder from the viewpoint of obtaining a very high noise generation reducing effect and excellent durability. Is preferable. The ratio (C / B) of the content (C) of the reinforcing material (carbon black) to the content (B) of the aramid powder with respect to 100 parts by mass of the rubber component in the rubber composition forming the compressed rubber layer 11 is preferable. 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) with respect to 100 parts by mass of the rubber component is the sum of the content of the layered silicate (A) and the content of the aramid powder (B). It is preferably more than (A + B). The content (A) of the layered silicate of the reinforcing material (carbon black) (C) and the content (B) of the aramid powder with respect to 100 parts by mass of the rubber component in the rubber composition forming the compressed rubber layer 11 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 oxide) 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. The cross-linking agent may be sulfur alone, organic peroxide alone, or both in combination. In the case of sulfur, the amount of the cross-linking agent blended 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 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 derivatives thereof. 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 as long as the effect of reducing abnormal noise due to the inclusion of the layered silicate and the aramid powder and the effect of excellent durability are not impaired.

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 the shape of a strip 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 fabric is transferred, from the viewpoint of suppressing the sound generated between the back rubber layer 13 and the flat pulley in contact with the back rubber layer 13.

Each of the adhesive rubber layer 12 and the back surface rubber layer 13 is formed of a rubber composition in which an uncrosslinked rubber composition obtained by blending various compounding agents with a rubber component and kneaded is heated and pressurized and crosslinked with a crosslinking agent. ing. Therefore, each of the adhesive rubber layer 12 and the back surface rubber layer 13 contains a crosslinked rubber component and various compounding agents. The back rubber layer 13 is preferably formed of a rubber composition slightly harder than the adhesive rubber layer 12 from the viewpoint of suppressing the occurrence of adhesion upon contact with the flat pulley.

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

Examples of the compounding agent include reinforcing materials such as carbon black, vulcanization aids, cross-linking agents, vulcanization accelerators, rubber compounding resins, and the like, as in the case of the compressed rubber layer 11.

The compressed rubber layer 11, the adhesive rubber layer 12, and the back surface rubber layer 13 may be formed of the same rubber composition or may be formed of different rubber compositions.

The core wire 14 is composed of twisted yarns 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 the molding process and / or is dried after being immersed in rubber glue in order to impart adhesiveness to the adhesive rubber layer 12 of the V-ribbed belt body 10. Adhesive treatment is applied.

According to the V-ribbed belt B according to the first embodiment of the above 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 shown in Examples described later, it is possible to obtain a very high noise generation reducing effect at the time of being flooded and to obtain excellent durability.

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

In the production of the V-ribbed belt B according to the first embodiment, as shown in FIGS. 3 and 4, a belt forming mold 20 provided concentrically and having a cylindrical inner mold 21 and an outer mold 22, respectively, is used.

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

In the production of the V-ribbed belt B according to the first embodiment, first, each compounding agent is mixed with the rubber component, kneaded with a kneader such as a kneader or a Banbury mixer, and the obtained uncrosslinked rubber composition is sheeted by calendar molding or the like. The uncrosslinked rubber sheet 11'for the compressed rubber layer 11 is produced by molding into a shape. The uncrosslinked rubber sheet 11'for the compressed rubber layer 11 is blended with a layered silicate and an aramid powder. Similarly, uncrosslinked rubber sheets 12'and 13'for the adhesive rubber layer and the back rubber layer are also produced. Further, after performing an adhesive treatment in which the twisted yarn 14'for the core wire is immersed in an RFL aqueous solution and heated, an adhesive treatment is performed in which the twisted yarn 14'is immersed in rubber glue and heat-dried.

Next, as shown in FIG. 5, a rubber sleeve 25 is placed on a cylindrical drum 24 having a smooth surface, and an uncrosslinked rubber sheet 13'for the back rubber layer and an uncrosslinked rubber sheet for the adhesive rubber layer are placed on the rubber sleeve 25. 12'is wound in order and laminated, and the twisted yarn 14'for the core wire is spirally wound around the cylindrical inner mold 21 from above, and the uncrosslinked rubber sheet 12'for the adhesive rubber layer is further wound from above. And the uncrosslinked rubber sheet 11'for the compressed rubber layer is wound in order to form the laminated body B'. At this time, the uncrosslinked rubber sheets 11', 12', and 13'are wound so that the columnar 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. 6, it is set in the inner peripheral surface side of the outer mold 22 in an inwardly fitted state.

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

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 pressurize the mold. 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 laminated body B'are compressed on the molded surface of the outer mold 22. Further, the cross-linking of these rubber components progresses and becomes integrated, and at the same time, it is combined with the twisted yarn 14', and finally, a cylindrical belt slab S is formed. 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 depressurized 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 can be obtained by turning it over. 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 the pulley layout of the auxiliary drive belt transmission device 30 of the automobile using the V-ribbed belt B according to the first embodiment. The auxiliary drive belt transmission device 30 is of a serpentine drive type in which a V-ribbed belt B is wound around six pulleys of four rib pulleys and two flat pulleys to transmit power.

The auxiliary drive belt transmission device 30 is provided with a rib pulley power steering pulley 31 at the uppermost position, and a rib pulley AC generator pulley 32 below the power steering pulley 31. A flat pulley tensioner pulley 33 is provided below the 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 crankshaft pulley 35 of a rib pulley is provided on the lower left side of the tensioner pulley 33, and an air conditioner pulley 36 of the rib pulley is provided on the lower right side of the crankshaft pulley 35. These pulleys are made of, for example, stamped metal products, castings, resin molded products such as nylon resin and phenol resin, and have a pulley diameter of φ50 to 150 mm.

In the auxiliary 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 is in contact with the power steering pulley 31, and then wound around the tensioner pulley 33 so as to be in contact with the back surface side of the belt. , The crankshaft pulley 35 and the air conditioner pulley 36 are wound in order so that the V-rib 15 side comes into contact with each other, and the water pump pulley 34 is wound so that the back surface side of the belt comes into contact with each other. 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 hung between the pulleys, is, for example, 50 to 300 mm. The misalignment that can occur between the pulleys is 0-2 °.

(Embodiment 2)
10 and 11 show the V-ribbed belt B according to the second embodiment. The part having the same name as that of the first embodiment is shown by using the same reference numeral as that of 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 perforated rubber and is provided in a layered manner 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 formed of solid rubber and is provided inside the surface rubber layer 11a to form 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, and the hollow portions and the concave holes 16 are dispersed. It includes both a structure arranged in a row and a structure in which a hollow portion and a concave hole 16 are communicated with each other. Further, the “solid rubber” in the present application means a crosslinked rubber composition that does not contain a hollow portion and a concave hole 16 other than the “porous rubber”.

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

Examples of the unexpanded hollow particles include particles in which a solvent is sealed inside a shell formed of a thermoplastic polymer (for example, an acrylonitrile-based polymer) or the like. Only one kind of hollow particles may be used, or two or more kinds of hollow particles may be used. The blending amount 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 with respect to 100 parts by mass of the rubber component. It is as follows. 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'-oxybisbenzenesulfonyl hydrazide as a main component. Examples thereof include OBSH-based foaming agents and organic foaming agents such as HDCA-based 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 as follows.

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 pore 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 determined by the number average of 50 to 100 pieces 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. Further, 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 of the above configuration, the rubber composition forming the surface rubber layer 11a of the compressed rubber layer 11 constituting the pulley contact portion on the inner peripheral side of the belt is a layered silicate and an aramid powder. By containing the above, 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, uncrosslinked rubber sheets 11a'and 11b' for the surface rubber layer and the inner rubber portion of the compressed rubber layer 11 are manufactured. Hollow particles and / or a foaming agent are blended in the uncrosslinked rubber sheet 11a'for the surface rubber layer. Next, by the same method as in the first embodiment, as shown in FIG. 12, the uncrosslinked rubber sheet 13'for the back rubber layer and the adhesive rubber are placed on the rubber sleeve 25 covered on the cylindrical drum 24 having a smooth surface. The unbridged rubber sheet 12'for the layer is wound in order and laminated, and the twisted thread 14'for the core wire is spirally wound around the cylindrical inner mold 21 from above, and further, for the adhesive rubber layer from above. 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 wound in this order to form a laminate B'. Then, the cylindrical belt slab S as shown in FIG. 13 is molded from the laminated body B'.

Other configurations and effects are the same as in the first embodiment.

(Embodiment 3)
14 and 15 show the V-ribbed belt B according to the third embodiment. The part having the same name as that of the first embodiment is shown by using the same reference numeral as that of 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 perforated rubber and is provided along the outer side surface portions of the V ribs 15 on both sides, and the opposite side surface portions of the pair of V ribs 15 adjacent to each other and those are provided. It is provided along the bottom of the ribs to be connected, and constitutes a 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 an outer side surface portion of each of the V ribs 15 on both sides or an opposite side surface portion of a 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 formed of solid rubber and is provided inside the surface rubber layer 11a to form 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 circumference of the belt slab S, ridges 15'with a substantially trapezoidal cross-sectional shape extending in the circumferential direction are formed 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 hung between the pair of slab connecting shafts 26, and V-rib-shaped grooves extending in the circumferential direction are continuously provided in the axial direction of the outer circumference with respect to the outer circumference of the belt slab S. The ground grinding wheel 27 is brought into contact with the ground while rotating, and the belt slab S is also rotated between the pair of slab transfer 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, and the plurality of V-ribs 15 are formed with the surface rubber layer 11a of the porous rubber. The inner rubber portion 11b of the solid rubber is configured.

Other configurations and effects are the same as those of Embodiments 1 and 2.

(Other embodiments)
In the first to third embodiments, the V-ribbed belt B is shown, but 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 inner peripheral side of the belt as shown in FIG. It may be a low-edge type V-belt B having a compression rubber layer 11 to form a flat belt B, or a flat belt B having an inner rubber layer 17 to form a pulley contact portion on the inner peripheral side of the belt as shown in FIG. 19B. You may.

(V ribbed belt)
V-ribbed belts having the same configurations as those of the second embodiment 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 (JSR 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 type vulcanizer. After kneading, 50 parts by mass of FEF carbon black (trade name: Seast SO manufactured by Tokai Carbon Co., Ltd.) as a reinforcing material and zinc oxide (Sakai Chemical) as a vulcanization aid are added to 100 parts by mass of this rubber component. Product name: Zinc oxide 3 types, 5 parts by mass, cross-linking agent sulfur (Product name: Seimi OT), 2 parts by mass, sulfenamide-based vulcanization accelerator (manufactured by Ouchi Shinko Kagaku Co., Ltd.) Product name: Noxeller MSA-G 2 parts by mass, 1st thiuram-based vulcanization accelerator (manufactured by Ouchi Shinko Kagaku Co., Ltd. Product name: Noxeller TET-G) 0.5 parts by mass, 2nd thiuram-based vulcanization accelerator ( Ouchi Shinko Kagaku Co., Ltd. Product name: Noxeller TBT 1 part by mass, Bentnite (Hojun product name: Hotaka, montmorillonite content 50% by mass) 50 parts by mass (Monmorironite 25 parts by mass), Aramid powder (Teijin Co., Ltd. product) Name: TW5011) 5 parts by mass, hollow particles (manufactured by Sekisui Chemical Co., Ltd., product name: Advancel EM403) by 2 parts by mass, and foaming agent (manufactured by Sankyo Kasei Co., Ltd., product name: Cellmic CE) by 7 parts by mass. A V-ribbed belt having a surface rubber layer of a compressed rubber layer formed by kneading was produced using the obtained uncrosslinked rubber composition, and this was designated 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 was 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 three.

<Example 2>
Using the uncrosslinked rubber composition obtained in the same manner as in Example 1 except that the amount of bentonite blended was 10 parts by mass (5 parts by mass) with respect to 100 parts by mass of the rubber component, the compressed rubber layer was used. A V-ribbed belt having a surface rubber layer formed was produced, and this was designated as Example 2.

<Example 3>
The uncrosslinked rubber obtained in the same manner as in Example 1 except that the blending amounts of bentonite and aramid powder were 30 parts by mass (15 parts by mass) and 10 parts by mass with respect to 100 parts by mass of the rubber component, respectively. A V-ribbed belt having a surface rubber layer of a compressed rubber layer formed using the composition was produced, and this was designated as Example 3.

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

<Example 5>
Using the uncrosslinked rubber composition obtained in the same manner as in Example 4 except that the amount of bentonite blended was 10 parts by mass (5 parts by mass) with respect to 100 parts by mass of the rubber component, the compressed rubber layer was used. A V-ribbed belt having a surface rubber layer formed was produced, and this was designated as Example 5.

<Comparative Examples 1 to 5>
Example 1 and Example 1 except that the amount of the aramid powder compounded 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 without blending bentonite. Using the uncrosslinked rubber composition obtained in the same manner, V-ribbed belts having a surface rubber layer of the compressed rubber layer formed were prepared and used as Comparative Examples 1 to 5, respectively.

<Comparative Examples 6 to 10>
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) with respect to 100 parts by mass of the rubber component without blending aramid powder. ), 50 parts by mass (25 parts by mass of montmorillonite), and 60 parts by mass (30 parts by mass of montmorillonite). V-ribbed belts having a surface rubber layer formed were prepared and used as Comparative Examples 6 to 10, respectively.

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

(Test method)
<Evaluation of abnormal noise when flooded>
FIG. 20A shows the pulley layout of the belt running tester 40 for evaluating abnormal noise when flooded.

The belt running tester 40 for evaluating abnormal noise when receiving water is provided with 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 located to the right 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 diagonally upward to the right of the drive pulley 41. 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 of the above. Then, in the belt running tester 40 for evaluating abnormal noise when flooded, the V-rib side of the V-ribbed belt B comes into contact with the drive pulley 41, the first and second driven pulleys 42, 43, which are rib pulleys, and the back side is a flat pulley. It is configured to be wound in contact with a certain idler pulley 44.

Each of the V-ribbed belts B of Examples 1 to 5 and Comparative Examples 1 to 10 is set in the belt running tester 40 for evaluating abnormal noise when receiving water, and a pulley is loaded so that a belt tension of 49 N per rib is applied. Positioning is performed, resistance is applied to the alternator to which the second driven pulley 43 is attached so that a current of 60 A flows, and the drive pulley 41 is rotated at a rotation speed of 800 rpm at room temperature to rotate the drive pulley 41 of the V-ribbed belt B. Water was dropped on the V-rib side of the V-ribbed belt B at a rate of 1000 ml per minute at the approaching portion. Then, regarding the abnormal noise generation situation when the belt is running, "S: No abnormal noise is generated at all. A: Abnormal noise is slightly observed. B: Abnormal noise is slightly generated. C. : Occurrence of abnormal noise is clearly observed. D: Occurrence of severe abnormal noise is observed. ”Was evaluated on a 5-point scale.

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

In the belt running tester 50 for heat resistance and durability evaluation, a large diameter driven pulley 51 and a drive pulley 52, which are rib pulleys having a pulley diameter of 120 mm, are provided at intervals in the vertical direction, and a pulley is provided in the middle of the vertical direction. An idler pulley 53, which is a flat pulley having a diameter of 70 mm, is provided, and a small diameter driven pulley 54, which is a rib pulley having a pulley diameter of 55 mm, is provided to the right of the idler pulley 53. The heat-resistant and durability evaluation belt running tester 50 is in contact with the large-diameter driven pulley 51, the drive pulley 52, and the small-diameter driven pulley 54, whose V-rib side of the V-ribbed belt B is a rib pulley, and whose back side is a flat pulley. It is configured to be wound in contact with the idler pulley 53. The idler pulley 53 and the small-diameter driven pulley 54 are each 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 belt running tester 50 for heat resistance and durability evaluation, and a rotational load of 11.8 kW was applied to the large-diameter driven pulley 51 to form a belt. A set weight of 834N was loaded laterally on 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 under an atmospheric temperature of 120 ° C. to run the belt. Then, a crack was generated in the compressed rubber layer of the V-ribbed belt B, and the traveling time until the crack reached the core wire was measured, and this was defined as the heat-resistant and durable life.

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

According to Tables 4 to 6, in Examples 1 to 5 in which the rubber composition forming the surface rubber layer of the compressed rubber layer contains the layered silicate montmorillonite and the aramid powder, the abnormal noise evaluation at the time of water exposure is S or Compared with A, which has a heat-resistant and durable life of 327 hours or more, has a very high effect of reducing abnormal noise when exposed to water, and has excellent durability, whereas it contains only one of the layered silicate montmorillonite and aramid powder. In Examples 1 to 10, it can be seen that none of them can obtain a very high effect of reducing the generation of abnormal noise when exposed to water, and some of them cannot obtain excellent durability.

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 Compressed rubber layer 11a Surface rubber layer 17 Inner rubber layer

Claims (14)

A friction transmission belt having a rubber layer that constitutes 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.
The rubber composition contains carbon black as a reinforcing material, 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 content of the aramid powder. Friction transmission belt that is more than the sum of the content. In 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. In 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. In 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 with respect to 100 parts by mass of the rubber component. In the friction transmission belt according to any one of claims 1 to 4.
A friction transmission belt in which the rubber composition is a porous rubber. In 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 with respect to 100 parts by mass of the rubber component. In the friction transmission belt according to any one of claims 1 to 6.
A friction transmission belt in which the content of the layered silicate with respect to 100 parts by mass of the rubber component in the rubber composition is larger than the content of the aramid powder. In the friction transmission belt according to any one of claims 1 to 7.
A friction transmission belt in which the carbon black is FEF. In the friction transmission belt according to any one of claims 1 to 8.
A friction transmission belt in which 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. In the friction transmission belt according to any one of claims 1 to 9.
A friction transmission belt in which the ratio of the content of the reinforcing material to the content of the layered silicate in 100 parts by mass of the rubber component in the rubber composition is 1 or more and 20 or less. In the friction transmission belt according to any one of claims 1 to 10.
A friction transmission belt in which the content of the reinforcing material with respect to 100 parts by mass of the rubber component in the rubber composition is larger than the content of the layered silicate. In 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 to 100 parts by mass of the rubber component in the rubber composition is 1.5 or more and 20 or less. In the friction transmission belt according to any one of claims 1 to 12.
A friction transmission belt in which the content of the reinforcing material with respect to 100 parts by mass of the rubber component in the rubber composition is larger than the content of the aramid powder. In the friction transmission belt according to any one of claims 1 to 13.
A friction transmission belt in which the ratio of the content of the reinforcing material to the sum of the content of the layered silicate and the content of the aramid powder with respect to 100 parts by mass of the rubber component in the rubber composition is 10 or less.

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