Friction transmission belts

Abstract

Friction transmission belts with a rubber layer forming a pulley mounting surface, wherein the rubber layer comprises a rubber composition containing polyolefin particles and an inorganic filler, the inorganic filler comprises both silicon dioxide and montmorillonite, or both silicon dioxide and calcium carbonate, in the rubber composition, the proportion of polyolefin particles per 100 parts by mass of a rubber component is 50 parts by mass or more, and in the rubber composition, the proportion of inorganic filler per 100 parts by mass of the rubber component is 35 parts by mass or more.

Description

TECHNICAL AREA

[0001] The present invention relates to a friction transmission belt. STATE OF THE ART

[0002] Prior art friction transmission belts have a pulley contact surface containing polyethylene particles distributed across and exposed on the pulley contact surface. Patent documents 1 to 3 disclose, for example, a multi-ribbed V-belt having a compressed rubber layer formed from a rubber composition containing ultra-high molecular weight polyethylene particles.

[0003] Patent document 4 relates to a multi-ribbed belt in which several multi-ribbed V-ribs, each extending in a longitudinal direction of the belt, are arranged side by side in the width direction of the belt on the inner surface of the belt, and which is wound around a pulley in order to bring the several multi-ribbed V-ribs into contact with the pulley for power transmission, as well as a drive belt system for motor vehicle auxiliary units using the same.

[0004] Furthermore, patent document 5 describes a belt, in particular a drive belt, which has a polymeric mixture in whole or in part, which is cured by radical mechanisms and / or radial-forming agents and which contains proportions of an ethylene alpha olefin elastomer. CITATED DOCUMENTS PATENT DOCUMENTS Patent document 1: JP 2007- 70 592 A Patent document 2: JP 2007- 170 454 A Patent document 3: JP 2007- 170 587 A Patent document 4: DE 11 2005 002 891 T5 Patent document 5: DE 10 2005 053 588 A1 Patent document 6: US 2012 / 0 021 858 A1 Patent document 7: JP 2007- 298 162 A Patent document 8: EP 2 631 507 A1 SUMMARY OF THE INVENTIONAL PROBLEM

[0005] The present invention is intended to reduce abnormal noise generation from a friction transmission belt when the belt is wet. SOLUTION TO THE PROBLEM

[0006] The present invention relates to a friction transmission belt with a rubber layer forming a pulley contact surface. The rubber layer comprises a rubber composition containing polyolefin particles and an inorganic filler. The inorganic filler comprises either silicon dioxide and montmorillonite, or either silicon dioxide and calcium carbonate. In the rubber composition, the proportion of polyolefin particles per 100 parts by mass of a rubber component is 50 parts by mass or more, and the proportion of the inorganic filler per 100 parts by mass of the rubber component is 35 parts by mass or more. ADVANTAGES OF THE INVENTION

[0007] In the present invention, a friction transmission belt comprises a rubber layer that acts as a pulley contact surface, formed from the rubber composition just described. This feature makes it possible to reduce abnormal noise generation from the friction transmission belt when it is wet. BRIEF DESCRIPTION OF THE DRAWING [ Fig. 1] Fig. Figure 1 shows a perspective view of a multi-ribbed belt according to a first embodiment. [ Fig. 2] Fig. Figure 2 shows a sectional view of a single wedge-shaped rib of the multi-ribbed belt according to the first embodiment. [ Fig. 3] Fig. Figure 3 shows a longitudinal section view of a belt forming tool. [ Fig. 4] Fig. Figure 4 shows an enlarged longitudinal section view of a section of the belt forming tool. [ Fig. 5] Fig.Figure 5 shows a first representation to illustrate a method for manufacturing the V-ribbed belt according to the first embodiment. [ Fig. 6] Fig. Figure 6 shows a second illustration of the method for manufacturing the V-ribbed belt according to the first embodiment. [ Fig. 7] Fig. Figure 7 shows a third illustration of the method for manufacturing the V-ribbed belt according to the first embodiment. [ Fig. 8] Fig. Figure 8 shows a fourth illustration of the method for manufacturing the V-ribbed belt according to the first embodiment. [ Fig. 9] Fig. Figure 9 shows an arrangement of pulleys for an auxiliary drive belt transmission system of a motor vehicle. [ Fig. 10] Fig. Figure 10 shows a perspective view of a multi-ribbed belt according to a second embodiment. [ Fig. 11] Fig. Figure 11 shows a sectional view of a single wedge-shaped rib of the multi-ribbed belt according to the second embodiment. [ Fig. 12] Fig. Figure 12 shows a first representation to illustrate a method for manufacturing the V-ribbed belt according to the second embodiment. [ Fig. 13] Fig. Figure 13 shows a second illustration to demonstrate the method for manufacturing the V-ribbed belt according to the second embodiment. [ Fig. 14] Fig. Figure 14 shows a perspective view of a multi-ribbed belt according to a third embodiment. [ Fig. 15] Fig. Figure 15 shows a sectional view of a single wedge-shaped rib of the multi-ribbed belt according to the third embodiment. [ Fig. 16A] Fig. Figure 16A shows a perspective view of a flank-open V-belt according to a further embodiment. [ Fig.16B] Fig. Figure 16B shows a perspective view of a flat belt according to a further embodiment. [ Fig. 17] Fig. Figure 17 shows an arrangement of pulleys of a belt running test device. DESCRIPTION OF EXECUTION FORMS

[0008] The following describes the embodiments in more detail with reference to the drawing. (First embodiment)

[0009] Fig. 1 and Fig. Figure 2 shows a multi-ribbed belt B (a friction transmission belt) according to a first embodiment. The multi-ribbed belt B according to the first embodiment is, for example, an endless belt used in a belt transmission system to drive an auxiliary unit located in the engine compartment of a motor vehicle. The multi-ribbed belt B according to the first embodiment has, for example, a length of 700 mm to 3000 mm, a width of 10 mm to 36 mm, and a thickness of 4.0 mm to 5.0 mm.

[0010] The multi-ribbed belt B according to the first embodiment has a three-layer multi-ribbed belt body 10 comprising a compressed rubber layer 11, which forms an inner surface section of the belt, an adhesive rubber layer 12, which forms a central section of the belt, and a stretchable rubber layer 13, which forms an outer surface section of the belt. A tensile cord 14 is embedded in a central section of the adhesive rubber layer 12 of the multi-ribbed belt body 10, such that the tensile cord 14 forms a helical pattern with a pitch in the transverse direction of the belt. The compressed rubber layer 11 has, for example, a thickness of 1.0 mm to 3.6 mm. The adhesive rubber layer 12 has, for example, a thickness of 1.0 mm to 2.5 mm. The stretchable rubber layer 13, for example, has a thickness of 0.4 mm to 0.8 mm.The stretchable rubber layer 13 can be replaced by a reinforcing fabric on the back.

[0011] The compressed rubber layer 11 comprises a plurality of wedge-shaped ribs 15 that project from the inner surface section of the belt. Each rib of the plurality of wedge-shaped ribs 15 is formed as a ridge extending longitudinally along the belt and has an approximately inverted triangular cross-section. The wedge-shaped ribs 15 are arranged parallel to one another in the transverse direction of the belt. The surfaces of the wedge-shaped ribs 15 enclosed in the compressed rubber layer 11 constitute a pulley contact surface that functions as a force transmission surface. The wedge-shaped ribs 15 each have, for example, a height of 2.0 mm to 3.0 mm and a width of 1.0 mm to 3.6 mm at a proximal end. The number of wedge-shaped ribs is, for example, three to six (six ribs in Fig. 1).

[0012] The compressed rubber layer 11 is formed from a rubber composition produced from a non-crosslinked rubber composition, which is manufactured by kneading a rubber component with various mixture components, including polyolefin particles and an inorganic filler. This non-crosslinked rubber composition is heated and compressed, causing the rubber component to crosslink. The resulting rubber composition is used for the compressed rubber layer 11. Thus, the rubber composition forming the compressed rubber layer 11 contains the crosslinked rubber component and various mixture components, including the polyolefin particles and the organic filler, which are dispersed within the rubber component.As shown in the examples, the V-ribbed belt B according to the first embodiment, as described later, reduces abnormal noise generation in damp conditions because the compressed rubber layer 11 forming the pulley contact surface is made from a rubber composition containing a predetermined amount of polyolefin particles and an inorganic filler, and the polyolefin particles are distributed and exposed on the pulley contact surface. In this case, the total proportion of polyolefin particles and inorganic filler in the rubber composition, based on 100 parts by mass of the rubber component, is preferably 85 parts by mass or more, more preferably 95 parts by mass or more, and even more preferably 105 parts by mass or more.

[0013] Examples of the rubber component of the rubber composition forming the compressed rubber layer 11 include: an ethylene α-olefin elastomer, such as an ethylene propylene diene terpolymer (hereinafter referred to as EPDM), ethylene propylene copolymer (EPM), ethylene butene copolymer (EDM), and ethylene octene copolymer (EOM); chloroprene rubber (CR); chlorosulfonated polyethylene rubber (CSM); and hydrogenated acrylonitrile rubber (H-NBR). Preferably, one or a mixture of two or more of these substances is used as the rubber component. The rubber component is preferably formed from an ethylene α-olefin elastomer and more preferably from EPDM.

[0014] Examples of the polyolefin particles to be included in the rubber composition include homopolymers such as polyethylene, polypropylene, poly-1-butene, and poly-4-methyl-1-pentene, and copolymers of ethylene and α-olefin, such as propylene, 1-butene, 1-hexene, 1-octene, and 4-methyl-1-pentene. Preferably, one, two, or more of these substances are used as the polyolefin resin particles, and even more preferably, particles of homopolymeric polyethylene are used.

[0015] Preferably, the total proportion of polyolefin particles and inorganic filler contained in the rubber composition is a predetermined amount or more. Furthermore, the proportion of polyolefin particles alone is also preferably a predetermined amount or more. For example, the proportion of polyolefin particles per 100 parts by mass of the rubber component is preferably 50 parts by mass or more. Furthermore, the proportion of polyolefin particles is preferably 70 parts by mass or more, and even more preferably 80 parts by mass or more.

[0016] To increase the wear resistance of the compressed rubber layer 11 forming the pulley contact surface and to reduce abnormal noise generation in the case of a wet multi-ribbed V-belt B, the polyolefin particles preferably comprise ultra-high molecular weight polyolefin particles with an average molecular weight (i.e., weight mean of molecular weight, number mean of molecular weight) of 500,000 or more, more preferably 1,000,000 or more, and even more preferably 1,500,000 or more. To increase the alternating bending strength, the ultra-high molecular weight polyolefin particles have an average molecular weight of 6,000,000 or less.

[0017] To increase the wear resistance of the compressed rubber layer 11 forming the pulley contact surface and to reduce abnormal noise generation in the case of a wet multi-ribbed V-belt B, the average particle diameter of the polyolefin particles is preferably 10 µm or more, and more preferably 100 µm or more. To increase the alternating bending strength, the average particle diameter is preferably 200 µm or less, more preferably 170 µm or less, and still more preferably 150 µm or less. The average particle diameter is obtained from the arithmetic mean of the diameters (i.e., the maximum outside diameters) of 50 to 100 particles actually measured in an observational image of the polyolefin particles taken by a scanning electron microscope, taking into account magnification.

[0018] To increase the wear resistance of the compressed rubber layer 11 forming the pulley contact surface and to reduce abnormal noise development in the case of a wet multi-ribbed belt B, the particle size distribution of the polyethylene particles is designed such that preferably 70 wt.% or more, more preferably 80 wt.% or more and even more preferably 90 wt.% or more of the polyethylene particles lie in the particle diameter range from 100 µm inclusive to 150 µm inclusive.

[0019] To increase the wear resistance of the compressed rubber layer 11 forming the pulley contact surface and to reduce the deterioration of power transmission performance due to belt slippage when the belt is wet, the polyolefin particles are preferably substantially spherical. The size ratio determined by dividing the maximum outer diameters of the polyolefin particles by their minimum outer diameters is preferably 2.00 or less, more preferably 1.50 or less, and even more preferably 1.30 or less. This size ratio is obtained as the arithmetic mean of the diameters, which is determined by dividing the maximum outer diameters of 50 to 100 particles (including inclusive) by the minimum outer diameters actually measured in a scanning electron microscope image of the polyolefin particles, taking magnification into account.If the polyolefin particles are in such a state prior to mixing that spherical particles with a diameter of 10 µm to 50 µm coagulate in clusters, it is preferred that the spherical particles are fused together by the heat applied during the formation of the belt and thus joined together and formed into a spherical or elliptical shape.

[0020] To increase the wear resistance of the compressed rubber layer 11 forming the pulley contact surface and to reduce the belt slippage-related deterioration of the power transmission performance when the belt is wet, the limiting viscosity [η] of the polyolefin particles measured in Decalin at 135 °C is preferably 5 dl / g or more, and to increase the alternating bending strength preferably 50 dl / g or less, and even more preferably 30 dl / g or less.

[0021] To increase the wear resistance of the compressed rubber layer 11 forming the pulley contact surface and to reduce the deterioration of power transmission performance due to belt slippage when the belt is wet, the melting point of the polyolefin particles is preferably 125 °C or more, more preferably 130 °C or more, and more preferably 145 °C or less. The melting point is determined by differential scanning calorimetry (DSC).

[0022] Examples of inorganic fillers included in the rubber composition further include silicon dioxide, layered silicate, calcium carbonate, and clay. Preferably, the inorganic filler is composed of one, two, or more of these materials. The total proportion of polyolefin particles and the inorganic filler contained in the rubber composition is preferably a predetermined amount or more. Furthermore, the proportion of the inorganic filler alone is also preferably a predetermined amount or more. For example, the proportion of the inorganic filler, based on 100 parts by mass of the rubber component, is preferably 30 parts by mass or more.

[0023] Examples of phyllosilicates used as inorganic fillers include the smectite family, the vermiculite family, and the kaolin family. Examples from the smectite family include montmorillonite, beidellite, saponite, and hectorite. Examples from the vermiculite family include trioctahedral vermiculite and dioctahedral vermiculite. Examples from the kaolin family include kaolinite, dickite, halloysite, lizardite, amesite, and chrysotile. Preferably, the phyllosilicate is composed of one or two or more of these materials. Even more preferably, montmorillonite is used as the phyllosilicate.

[0024] Preferably, the silicon dioxide contained in the inorganic filler does not receive any adhesion-promoting treatment. Furthermore, based on 100 parts by mass of the rubber component, preferably 30 parts by mass or more, and even more preferably 40 parts by mass or more, of silicon dioxide are contained in the rubber composition.

[0025] It should be noted that the inorganic filler preferably contains silicon dioxide and montmorillonite.

[0026] Examples of other mixture components included in the rubber composition include carbon black, a processing aid, a vulcanization aid, a crosslinker, and a co-crosslinker.

[0027] Examples of carbon black include: gas carbon black; furnace carbon black, such as SAF, ISAF, N-339, HAF, N-351, MAF, FEF, SRF, GPF, ECF, and N-234; thermal carbon black, such as FT and MT; and acetylene carbon black. In this embodiment, the proportion of carbon black included primarily for blackening the rubber composition is preferably smaller than in a case where the carbon black is intended to be included as a reinforcing material. The proportion of carbon black, based on 100 parts by mass of the rubber component, may be, for example, 15 parts by mass or less, 10 parts by mass or less, and 5 parts by mass or less.

[0028] Examples of the processing aid include stearic acid, polyethylene wax, and a metal salt of a fatty acid. Preferably, the processing aid is composed of one or two or more of these substances. The proportion of the processing aid in the rubber composition forming the compressed rubber layer 11 is preferably 0.1 to 3 parts by mass of the rubber component, based on 100 parts by mass.

[0029] Examples of vulcanizing aids include metal oxides, such as zinc oxide (zinc white) and magnesium oxide. Preferably, the vulcanizing aid is composed of one, two, or more of these substances. The proportion of the vulcanizing aid, based on 100 parts by mass of the rubber component, is, for example, 1 to 10 parts by mass.

[0030] Examples of crosslinking agents include organic peroxide and sulfur. Organic peroxide alone, sulfur alone, or a combination of these substances can be used as a crosslinking agent. For example, if the crosslinking agent is organic peroxide, its proportion, based on 100 parts by mass of the component, is 0.5 to 8 parts by mass. If the crosslinking agent is sulfur, its proportion, based on 100 parts by mass of the component, is 0.5 to 4 parts by mass.

[0031] Examples of the co-crosslinker include trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate, triallyl isocyanurate, liquid polybutadiene, and N,N'-m-phenylene bismaleimide. Preferably, the co-crosslinker is composed of one or two or more of these substances. The proportion of the co-crosslinker in the rubber composition forming the compressed rubber layer 11 is preferably 0.5 to 7 parts by mass of the rubber component, based on 100 parts by mass.

[0032] The adhesive rubber layer 12 is formed in the form of a strip having a horizontally elongated rectangular cross-section. The stretchable rubber layer 13 is also formed in the form of a strip with a horizontally elongated rectangular cross-section. Preferably, one surface of the stretchable rubber layer 13 has a fabric-mediated pattern to reduce noise generated between the stretchable rubber layer 13 and a flat belt pulley bearing against the stretchable rubber layer 13.

[0033] The adhesive rubber layer 12 and the stretchable rubber layer 13 are each formed from a rubber composition produced by heating and pressing a non-crosslinked rubber composition, which is produced by kneading a rubber component mixed with various other ingredients, and by crosslinking the kneaded product using a crosslinking agent. Thus, the adhesive rubber layer 12 and the stretchable rubber layer 13 each contain the crosslinked rubber component and various other ingredients. To reduce adhesion between the stretchable rubber layer 13 and the flat belt pulley bearing against the stretchable rubber layer 13, the stretchable rubber layer 13 is preferably formed from a rubber composition that is slightly harder than the rubber composition of the adhesive rubber layer 12.

[0034] Examples of the rubber components of the rubber compositions forming the adhesive rubber layer 12 and the stretchable rubber layer 13 include ethylene α-olefin elastomer, chloroprene rubber (CR), chlorosulfonated polyethylene rubber (CSM), and hydrogenated acrylonitrile butadiene rubber (H-NBR). These rubber components are preferably the same material as the rubber component of the compressed rubber layer 11.

[0035] As with the compressed rubber layer 11, examples of the compound include a reinforcing material, such as a carbon black, a filler, a processing aid, a vulcanizing aid, a crosslinker and a co-crosslinker.

[0036] The compressed rubber layer 11, the adhesive rubber layer 12, and the stretchable rubber layer 13 can be made from the same rubber composition. Alternatively, layers 11, 12, and 13 can be made from different rubber compositions.

[0037] The tensile cord 14 consists of a yarn made of fibers such as polyester fibers (PET), polyethylene naphthalate fibers (PEN), aramid fibers, and vinylon fibers. The diameter of the tensile cord 14 is, for example, 0.5 mm to 2.5 mm. The distance between the centers in the cross-section of the adjacent tensile cords 13 is, for example, 0.05 mm to 0.20 mm. To impart adhesion to the adhesive rubber layer 12 of the multi-ribbed belt body 10, the tensile cord 14 undergoes an adhesion-promoting treatment before the belt is formed. In the adhesion-promoting treatment, the tensile cord 14 is impregnated in an aqueous RFL solution and then heated and / or impregnated in a rubber solution and then dried. (Method for manufacturing the multi-ribbed belt)

[0038] Now, a method for manufacturing the V-ribbed belt B according to the first embodiment is described.

[0039] In the production of the multi-ribbed belt B according to the first embodiment, a belt forming tool 20 is used. As in Fig. 3 and Fig. As shown in Figure 4, the belt forming tool 20 comprises a cylindrical inner shape 21 and a cylindrical outer shape 22, which are arranged concentrically to each other.

[0040] The inner form 21 of the belt forming tool 20 is made of a flexible material, such as rubber. The outer form 22 is made of a rigid material, such as metal. The inner circumferential surface of the outer form 22 serves as the forming surface and has wedge-shaped rib-forming grooves 23 arranged at regular intervals in an axial direction. The outer form 22 is equipped with a temperature control mechanism through which a heating medium, such as steam, or a cooling medium, such as water, can flow and regulate the temperature. The belt forming tool 20 is equipped with a pressing unit that serves to press and expand the inner form 21 from the inside.

[0041] In the manufacture of the multi-ribbed belt B according to the first embodiment, compound components are added to a rubber component, and the mixture is kneaded using a mixing machine, such as a kneader and a Banbury mixer. The resulting non-crosslinked rubber composition is formed into a layer, for example by calendering, to create a non-crosslinked rubber layer 11' to form a compressed rubber layer 11. A predetermined quantity or more of polyolefin particles and inorganic filler is added to the non-crosslinked rubber layer 11' to form the compressed rubber layer 11.

[0042] Non-crosslinked rubber layers 12' and 13' for the formation of the adhesive rubber layer 12 and the stretchable rubber layer 13 are formed in a similar manner. After the adhesion-promoting treatment, in which the yarn 14', which is to form the tensile cord 14, is impregnated in an aqueous RFL solution and heated, an adhesion-promoting treatment is carried out in which the yarn 14' is impregnated in a rubber solution, heated, and dried.

[0043] Next, as in Fig.Figure 5 shows a rubber sleeve 25 placed on a cylindrical drum 24 having a smooth surface such that it covers the cylindrical drum 24. Then, the non-crosslinked rubber layer 13' to form the stretchable rubber layer 13 and the non-crosslinked rubber layer 12' to form the adhesive rubber layer 12 are successively wound and layered onto the rubber sleeve 25. Next, the yarn 14' to form the tensile strand 14 is wound spirally around the cylindrical inner form 21, and another non-crosslinked rubber layer 12' to form the adhesive rubber layer 12 and the non-crosslinked rubber layer 11' to form the compressed rubber layer are successively wound and layered onto the wound yarn 14', thereby forming a layered body S'.In this process, the non-crosslinked rubber layers 11', 12' and 13' are wound so that their fiber direction corresponds to a belt longitudinal direction (i.e. a circumferential direction).

[0044] Next, the rubber sleeve 25, which has the layered body S', is removed from the cylindrical drum 24 and then as in Fig. 6 shown attached to the inner circumferential surface of the outer shape 22.

[0045] Next, the inner form 21 will be as shown in Fig. 7 shown in the rubber sleeve 25, which is placed in the outer form 22 and hermetically sealed.

[0046] The outer mold 22 is then heated, and the inner mold 21 is pressed, for example, by high-pressure air introduced into the hermetically sealed interior of the inner mold 21. During this process, the inner mold 21 expands, as described in Fig.As shown in Figure 8, the non-crosslinked rubber layers 11', 12', and 13' of the layer body S', forming a belt, are pressed against the forming surface of the outer mold. Simultaneously, the crosslinking of the rubber component in the layers is promoted, and the layers are integrally bonded to the yarn 14'. This creates a cylindrical belt blank S. The molding temperature of the belt blank S is, for example, 100 °C to 180 °C. The molding pressure is, for example, 0.5 MPa to 2.0 MPa. The molding time is, for example, 10 minutes to 60 minutes.

[0047] The pressure inside the inner mold 21 is then reduced, thus releasing the seal, and the belt blank S formed by the rubber sleeve 25 between the inner mold 21 and the outer mold 22 is demolded. The belt blank S is cut into rings of predetermined width and turned inside out, yielding the multi-ribbed V-belt B. If necessary, an outer circumferential surface of the belt blank S, i.e., a surface of the belt blank S in the direction of the wedge-shaped ribs 15, can be polished.

[0048] Fig.Figure 9 next shows an arrangement of pulleys of an auxiliary drive belt transmission system 30 of a motor vehicle, which uses the multi-ribbed belt B according to the first embodiment. The auxiliary drive belt transmission system 30 is a serpentine drive system in which the multi-ribbed belt B is wound around six pulleys for power transmission. The six pulleys comprise four ribbed belt pulleys and two flat belt pulleys.

[0049] The auxiliary drive belt transmission system 30 comprises, at its uppermost position, a power steering pump pulley 31, which is a ribbed belt pulley, and an alternator pulley 32, which is also a ribbed belt pulley, located below the power steering pump pulley 31. The system 30 also comprises a tensioner pulley 33, which is a flat belt pulley, located to the left and below the power steering pump pulley 31, and a water pump pulley 34, which is also a flat belt pulley, located below the tensioner pulley 33. The system 30 further comprises a crankshaft pulley 35, which is a ribbed belt pulley, located to the left and below the tensioner pulley 33, and an air conditioning compressor pulley 36, which is a ribbed belt pulley, located to the right and below the crankshaft pulley 35.These pulleys are formed, for example, from pressed metal parts or castings, or from resin molded sections made of, for example, nylon resin and phenolic resin, with a pulley diameter of φ50 mm to φ150 mm.

[0050] In the auxiliary drive belt transmission system 30, the multi-ribbed belt B is wound around the power steering pump pulley 31 with its wedge-shaped ribs 15 in contact with the power steering pump pulley 31, and then around the tensioner pulley 33 with its back side in contact with the tensioner pulley 33. Next, the belt B is wound successively around the crankshaft pulley 35 and the air conditioning compressor pulley 36 with its wedge-shaped ribs 15 in contact with the crankshaft pulley 35 and the air conditioning compressor pulley 36, respectively, and then around the water pump pulley 34 with its back side in contact with the water pump pulley 34. Finally, the belt B is wound around the alternator pulley 32 with its wedge-shaped ribs 15 in contact with the alternator pulley 32 and returns to the power steering pump pulley 31 at the end.The belt run length, which is the length of the multi-ribbed belt B between the pulleys, is, for example, 50 mm to 300 mm. The permissible misalignment between the pulleys is 0° to 2°.

[0051] The following describes one reason why the belt according to this embodiment reduces abnormal noise generation in damp conditions. Firstly, the abnormal noise generation in damp conditions mentioned in the present application is due to a so-called stick-slip effect at a friction point between the pulley contact surface of the power transmission belt and a pulley. When the power transmission belt is damp, the coefficient of friction of the transmission belt decreases. If the friction area has both a damp and a dry section, the frictional force fluctuates depending on the section. This easily leads to the stick-slip effect and ultimately to abnormal noise generation.

[0052] However, if the entire friction area is damp, the stick-slip effect is reduced. For this reason, the rubber layer in the pulley contact surface is made of a rubber compound containing an inorganic filler, allowing the pulley contact surface to remain slightly damp and thus reducing the stick-slip effect. The polyolefin particles contained in the rubber layer forming the pulley contact surface contribute to reducing the decrease in power transmission performance. Wet sections of the particles exposed on the pulley contact surface lead to an increase in the frictional force between the power transmission belt and a pulley due to capillary action, and consequently, an increase in the resulting stick-slip effect.To counteract this problem, the belt, according to the present disclosure, incorporates polyolefin particles that are less prone to moisture absorption, thereby reducing the occurrence of capillary forces. This feature makes it possible to reduce the risk of stick-slip and the occurrence of abnormal noise. It should be noted that the polyolefin particles also have an effect that improves the wear resistance of the rubber layer incorporated into the pulley contact surface.

[0053] As can be seen, the silicon dioxide contained in the inorganic filler preferably does not receive any adhesion-promoting treatment. Specifically, when silicon dioxide is added to the rubber composition, it is usually treated with a silane adhesion promoter to improve its dispersibility within the rubber component. In this embodiment, however, the silicon dioxide can preferably be used without any adhesion-promoting treatment. Furthermore, no adhesion promoter is preferably used as a component of the rubber composition. Consequently, the rubber composition contains highly hydrophilic silicon dioxide, so that the belt's pulley contact surface becomes slightly damp. This feature is desirable for reducing abnormal noise generation.

[0054] The inorganic filler also preferably comprises calcium montmorillonite. Montmorillonite absorbs cations, such as sodium. +, K + , Ca 2+ , Mg 2+ The most strongly absorbed cations are Na cations such as Na + and Ca cations such as Ca 2+ Compared to Na-montmorillonite, Ca-montmorillonite is distinguished by its absorption capacity and is suitable for a requirement present in this embodiment, namely to make the pulley contact surface easily moistenable. (Second embodiment)

[0055] Fig. 10 and Fig. Figure 11 shows the multi-ribbed belt B according to a second embodiment. The same reference numerals were used to identify the same elements as in the first embodiment.

[0056] According to the second embodiment, the compressed rubber layer 11 of the multi-ribbed belt B comprises a surface rubber layer 11a and an inner rubber section 11b. The surface rubber layer 11a is applied to the entire surface of the wedge-shaped ribs 15. The surfaces of the wedge-shaped ribs 15 enclosed in the surface rubber layer 11a constitute a pulley contact surface that functions as a force transmission surface. The surface rubber layer 11a has, for example, a thickness of 50 µm to 500 µm. The inner rubber section 11b is located within the surface rubber layer 11a and forms the remaining portion of the compressed rubber layer 11, in addition to the surface rubber layer 11a.

[0057] Similar to the compressed rubber layer 11 according to the first embodiment, the surface rubber layer 11a is formed from a rubber composition containing a cross-linked rubber component and various mixture components, including polyolefin particles and an inorganic filler, which are dispersed in the rubber component. The total amount of the dispersed polyolefin particles and the dispersed inorganic filler is predetermined.

[0058] The inner rubber section 11b is formed from a rubber composition containing a cross-linked rubber component and various mixture constituents. The rubber composition forming the inner rubber section 11b may contain the polyolefin particles and the inorganic filler. The rubber composition forming the inner rubber section 11b may correspond to the rubber composition forming the adhesive rubber layer 12 or the stretchable rubber layer 13.

[0059] In the V-ribbed belt B described above, according to the second embodiment, the rubber layer 11a encompassed in the pulley contact surface is formed from the rubber composition containing the polyolefin particles and the inorganic filler. The total quantity of the dispersed polyolefin particles and the inorganic filler is a predetermined amount or more. This feature improves the hydrophilicity of the pulley contact surface and allows the polyolefin particles to be dispersed and exposed within the pulley contact surface. Therefore, the V-ribbed belt B can reduce abnormal noise generation in humid conditions, as demonstrated in examples described later.

[0060] To manufacture the multi-ribbed belt B according to the second embodiment, non-crosslinked rubber layers 11a', 11b' are produced to form the surface rubber layer and the inner rubber section of the compressed rubber layer 11. A predetermined quantity or more of polyolefin particles and organic filler is added to the non-crosslinked rubber layer 11a' forming the surface rubber layer. Next, as in Fig.Figure 12 shows a process similar to that of the first embodiment in which the non-crosslinked rubber layer 13' for forming a stretchable rubber layer and the non-crosslinked rubber layer 12' for forming an adhesive rubber layer are successively wound and layered onto the rubber sleeve 25, which is placed on the cylindrical drum having a smooth surface. The yarn 14' is then wound spirally around the cylindrical inner form 21 to form the tensile strand 14. A further non-crosslinked rubber layer 12' for forming the adhesive rubber layer 12, a non-crosslinked rubber layer 11b' for forming the inner rubber section of the compressed rubber layer 11, and a non-crosslinked rubber layer 11a' for forming the surface rubber layer are successively wound and layered onto the wound yarn 14', thereby forming a layered body S'.From this layered body S', as in . Fig. 13 shows a cylindrical belt blank S formed.

[0061] The other features and advantages are the same as those of the first embodiment. (Third embodiment)

[0062] Fig. 14 and Fig. Figure 15 shows the multi-ribbed belt B according to a third embodiment. The same reference numerals were used to identify the same elements as in the first embodiment.

[0063] According to the third embodiment, the compressed rubber layer 11 of the multi-ribbed belt B comprises the surface rubber layer 11a and the inner rubber section 11b. The surface rubber layer 11a is formed from a porous rubber layered over the entire surface of the wedge-shaped ribs 15 and forms a pulley contact surface of the inner surface section of the belt. The surface rubber layer 11a has, for example, a thickness of 50 µm to 500 µm. The inner rubber section 11b is formed from a solid rubber layer located within the surface rubber layer 11a and forms the other section of the compressed rubber layer 11 adjacent to the surface rubber layer 11a.

[0064] The term "porous rubber" as used here refers to a cross-linked rubber composition containing many hollow sections and a surface with many depressions 16. It can have either a structure in which the hollow sections and depressions 16 are distributed or a structure in which the hollow sections and depressions 16 communicate with each other. The term "solid rubber" as used here refers to a cross-linked rubber composition that is not formed from "porous rubber" and does not contain hollow sections or depressions 16.

[0065] As with the compressed rubber layer 11 according to the first embodiment, the surface rubber layer 11a is formed from a rubber composition containing a cross-linked rubber component and various mixture components, including polyolefin particles and an inorganic filler, dispersed within the rubber component. The total amount of dispersed polyolefin particles and filler is a predetermined quantity or more. Furthermore, the surface rubber layer 11a is formed from a porous rubber. Thus, prior to its formation as the surface rubber layer 11a, the non-cross-linked rubber composition contains unexpanded hollow particles and / or a blowing agent to form porous rubber.

[0066] Examples of the non-expanded hollow particles include particles containing a solvent encapsulated in a shell formed from a thermoplastic polymer (e.g., an acrylonitrile polymer) or another suitable material. The hollow particles may be composed of one type or of two or more types of these particles. The proportion of these hollow particles is preferably 0.5 to 10 parts by weight of the rubber component per 100 parts by weight. Examples of the blowing agent include organic blowing agents, such as an ADCA blowing agent containing azodicarbonamide as the main component, a DPT blowing agent containing dinitrosopentamethylenetetramine as the main component, an OBSH blowing agent containing p,p'-oxybisbenzenesulfonylhydrazide as the main component, and an HDCA blowing agent containing hydrazodicarbonamide as the main component. Preferably, the blowing agent is composed of one type or of two or more types of these substances.Based on 100 parts by mass of the rubber component, the proportion of blowing agent is preferably 0.5 to 10 parts by mass.

[0067] The surface rubber layer 11a, which is formed from a porous rubber, has a surface with many depressions 16. The mean diameter of the depressions 16 is preferably 10 µm to 150 µm. The mean diameter of the depressions 16 is determined by the number-mean diameter of 50 to 100 depressions measured on the surface image.

[0068] The inner rubber section 11b is formed from a rubber composition containing a cross-linked rubber component and various mixture constituents. The rubber composition forming the inner rubber section 11b can correspond to the rubber composition forming the surface rubber layer 11a, with the exception of the hollow sections and the depressions 16.

[0069] The rubber composition forming the inner rubber section 11b may contain the polyolefin particles and the inorganic filler. The rubber composition forming the inner rubber section 11b may correspond to the rubber composition forming the adhesive rubber layer 12 or the stretchable rubber layer 13.

[0070] The multi-ribbed belt B according to the third embodiment can reduce abnormal noise generation in the wet condition, as shown in examples described later, since the surface rubber layer 11a forming the pulley contact surface is formed from the rubber composition which contains the polyolefin particles and the inorganic filler in a predetermined quantity or more, so that the hydrophilicity of the pulley contact surface is improved and the polyolefin particles are distributed in the pulley contact surface and are exposed thereon.

[0071] To manufacture the V-ribbed belt B according to the third embodiment, non-crosslinked rubber layers 11a', 11b' are produced to form the surface rubber layer and the inner rubber section of the compressed rubber layer 11. In addition to a predetermined quantity or more of polyolefin particles and inorganic filler, hollow particles and / or a blowing agent are added to the non-crosslinked rubber layer 11a' to form the surface rubber layer. Next, as described in Fig. 12 and Fig.In the second embodiment, a non-crosslinked rubber layer 13' for forming a stretchable rubber layer and a non-crosslinked rubber layer 12' for forming an adhesive rubber layer are successively wound and layered onto the rubber sleeve 25, which is placed on the cylindrical drum 24 having a smooth surface, using a method similar to that of the second embodiment. The yarn 14' is then wound spirally around the cylindrical inner form 21 to form the tensile strand 14. A further non-crosslinked rubber layer 12' for forming the adhesive rubber layer, a non-crosslinked rubber layer 11b' for forming the inner rubber section of the compressed rubber layer 11, and a non-crosslinked rubber layer 11a' for forming the surface rubber layer are successively wound and layered onto the wound yarn 14', thereby forming a layered body S'.A cylindrical belt blank S is formed from this layered body S'.

[0072] The other features and advantages are the same as those of the first embodiment. (Other embodiments)

[0073] In embodiments one to three described above, the multi-ribbed V-belt B was described as a non-limiting example of the friction transmission belt. The friction transmission belt can also be (i) an open-flanked V-belt B having the compressed rubber layer 11 enclosed in the pulley contact surface on the inside of the belt, as shown in Fig. 16A, or (ii) be a flat belt B having the inner rubber layer 17 enclosed in the pulley mounting surface on the inner surface section of the belt, as shown in Fig. 16B is shown. EXAMPLES (serpentine belt)

[0074] Multi-ribbed belts were manufactured according to the following examples 1 to 13 and the comparative examples 1 to 5. The respective composition of the belts is also shown in Tables 1 and 2. <Beispiel 1>

[0075] An EPDM was placed as a rubber component in a chamber of a Banbury internal mixer and masticated therein. Subsequently, the following were added to the rubber composition, based on 100 parts by mass of this rubber component: 2 parts by mass of ISAF carbon black, 50 parts by mass of polyethylene resin particles (manufactured by Mitsui Chemicals, Inc., trade name: HI-ZEX MILLION 240S, average molecular weight: approx. 2 million), 40 parts by mass of silicon dioxide (manufactured by Degussa AG, trade name: ULTRASIL VN3), 40 parts by mass of layered silicate (manufactured by Hojun Co., Ltd., trade name: Montmorillonite Hotaka), 5 parts by mass of calcium carbonate (manufactured by Shiraishi Kogyo Kaisya Ltd., trade name: ACTIFORT 700), 2.6 parts by mass of hollow particles (manufactured by Sekisui Chemical Co., Ltd., trade name: EM403), 7.3 parts by mass of blowing agent (Sankyo Kasei Co. Ltd.).0.5 parts by weight of stearic acid (trade name: Cell-Mike CE), 5 parts by weight of zinc oxide, 8 parts by weight (actually 3.2 parts by weight considering purity) of crosslinker made from organic peroxide with a purity of 40 wt% (manufactured by NOF Corporation, trade name: PEROXYMON F40), and 2 parts by weight of co-crosslinker (Seiko Chemical Co. Ltd., trade name: Hi-Cross M) were added and kneaded. This resulted in a non-crosslinked rubber composition. Using the obtained non-crosslinked rubber composition for the surface rubber layer of the compressed rubber layer, a multi-ribbed V-belt with a composition similar to that in the third embodiment, Example 1, was produced.

[0076] The silicon dioxide (ULTRASIL VN3) does not receive any adhesion-promoting treatment. Furthermore, Montmorillonite Hotaka is calcium montmorillonite modified with sodium carbonate.

[0077] Furthermore, the total proportion of polyolefin particles and inorganic filler is the total amount of polyolefin particles, silicon dioxide, layered silicate, and calcium carbonate. Therefore, the total proportion is 135 parts by mass. (Tables 1 and 2 also show the total proportions.)

[0078] The inner rubber sections of the compressed rubber layer, the adhesive rubber layer, and the backing rubber layer were each formed from a rubber compound containing EPDM as a rubber component. A tensile cord was formed from a twisted strand of polyethylene terephthalate fibers. The belt was 900 mm long, 21.36 mm wide, and 4.3 mm thick, and comprised six ribs. The surface of the wedge-shaped ribs was polished. <Beispiel 2>

[0079] In the non-crosslinked rubber composition used in Example 1, 40 parts by mass of Ben-Gel Blight 11 (trade name), manufactured by Hojun Co., Ltd., were used as montmorillonite (i.e., as a type of inorganic filler) per 100 parts by mass of the rubber component (this also applies hereafter). Example 2 involved the production of a multi-ribbed V-belt which, apart from the montmorillonite, had the same compositions as those in Example 1. <Beispiel 3>

[0080] In the non-crosslinked rubber composition used in Example 2, the proportion of polyethylene resin particles was 70 parts by mass, and no blowing agent was included. Example 3 involved the production of a multi-ribbed V-belt which, apart from the polyethylene resin particles and the absence of blowing agent, had the same composition as that in Example 2. <Beispiel 4>

[0081] In the non-crosslinked rubber composition used in Example 2, the proportion of polyethylene resin particles was 100 parts by mass, the proportion of hollow particles was 3.1 parts by mass, and no blowing agent was included. Example 4 involved the production of a multi-ribbed V-belt which, apart from the polyethylene resin particles, the hollow particles, and the absence of blowing agent, had the same compositions as those in Example 2. <Beispiel 5>

[0082] In the non-crosslinked rubber composition used in Example 1, 80 parts by mass of HI-ZEX MILLION 630M (trade name), manufactured by Mitsui Chemicals, Inc., were used as polyethylene particles, and 20 parts by mass of Ben-Gel W-100 (trade name), manufactured by Hojun Co., Ltd., were used as montmorillonite. No blowing agent was included. Example 5 was a multi-ribbed V-belt manufactured with the same composition as that in Example 1, except for these substances.

[0083] The average molecular weight of the polyolefin particles used (HI-ZEX MILLION 630M) was approximately 5,900,000. Furthermore, the montmorillonite used (Ben-Gel W-100) was sodium montmorillonite. <Beispiel 6>

[0084] In the non-crosslinked rubber composition used in Example 5, 40 parts by mass of Ben-Gel Blight 11 were used as montmorillonite. Furthermore, 2.7 parts by mass of hollow particles were included. Example 6 involved the production of a multi-ribbed V-belt, which, apart from these substances, had the same composition as that in Example 5. <Beispiel 7>

[0085] In the non-crosslinked rubber composition used in Example 6, 30 parts by mass of ULTRASIL VN3 were used as silicon dioxide. Furthermore, the proportion of carbon black was 12 parts by mass. As Example 7, a multi-ribbed V-belt was manufactured which, apart from these substances, had the same compositions as that in Example 6. <Beispiel 8>

[0086] In the non-crosslinked rubber composition used in Example 5, 80 parts by mass of HI-ZEX MILLION 240S were used as polyethylene particles. Example 8 involved the production of a multi-ribbed V-belt which, apart from the HI-ZEX MILLION 240S, had the same compositions as those in Example 5. <Beispiel 9>

[0087] In the non-crosslinked rubber composition used in Example 8, 40 parts by mass of Ben-Gel Blight 11 were used as montmorillonite. Furthermore, 2.7 parts by mass of hollow particles were included. Example 9 involved the production of a multi-ribbed V-belt, which, apart from these substances, had the same composition as that in Example 8. <Beispiel 10>

[0088] In the non-crosslinked rubber composition used in Example 9, 2 parts by mass of HAF carbon black were used as carbon black. Furthermore, the silicon dioxide content was 60 parts by mass. No montmorillonite was included. As Example 10, a multi-ribbed V-belt was produced which, apart from these substances, had the same compositions as that in Example 9. <Beispiel 11>

[0089] In the non-crosslinked rubber composition used in Example 9, 50 parts by mass of HI-ZEX MILLION 240S were used as polyethylene particles. The silicon dioxide content was also 50 parts by mass. No montmorillonite was included. Example 11 involved the production of a multi-ribbed V-belt, which, apart from these substances, had the same composition as that in Example 9. <Beispiel 12>

[0090] In the non-crosslinked rubber composition used in Example 11, the proportion of polyethylene particles was 40 parts by mass. Example 12 involved the production of a multi-ribbed V-belt which, apart from the polyethylene particles, had the same composition as that in Example 11. <Beispiel 13>

[0091] In the non-crosslinked rubber composition used in Example 11, the proportion of polyethylene particles was 30 parts by mass. Example 13 involved the production of a multi-ribbed V-belt which, apart from the polyethylene particles, had the same composition as that in Example 11. <Vergleichsbeispiel 1>

[0092] In the non-crosslinked rubber composition used in Example 1, 22 parts by mass of ISAF carbon black were used as carbon black. 20 parts by mass of HI-ZEX MILLION 240S were used as polyethylene particles. No silicon dioxide was included. 40 parts by mass of Montmorillonite Hotaka were used as montmorillonite. No calcium carbonate was included. No blowing agent was included. As a comparison, a multi-ribbed V-belt was manufactured which, apart from these substances, had the same compositions as those in Example 1. <Vergleichsbeispiel 2>

[0093] In the non-crosslinked rubber composition used in Comparative Example 1, 42 parts by mass of ISAF carbon black were used as carbon black. 40 parts by mass of Ben-Gel HVP, manufactured by Hojun Co., Ltd., were used as montmorillonite. 2.9 parts by mass of hollow particles were used. Comparative Example 2 involved the production of a multi-ribbed V-belt, which, apart from these substances, had the same compositions as that in Comparative Example 1.

[0094] The montmorillonite used (Ben-Gel HVP) was Na-montmorillonite. <Vergleichsbeispiel 3>

[0095] In the non-crosslinked rubber composition used in Comparative Example 1, 42 parts by mass of ISAF carbon black were used. 30 parts by mass of HI-ZEX MILLION 240S were used as polyethylene particles. 20 parts by mass of ULTRASIL VN3 were used as silicon dioxide. 20 parts by mass of Ben-Gel Blight 11 were used as montmorillonite. 5 parts by mass of calcium carbonate were used. 2.7 parts by mass of hollow particles were used. Comparative Example 3 was a multi-ribbed V-belt that, apart from these substances, had the same compositions as those in Comparative Example 1. <Vergleichsbeispiel 4>

[0096] In the non-crosslinked rubber composition used in Comparative Example 1, 42 parts by mass of ISAF carbon black were used as carbon black. 50 parts by mass of HI-ZEX MILLION 240S were used as polyethylene particles. 30 parts by mass of Ben-Gel Blight 11 were used as montmorillonite. 7.3 parts by mass of Cell-Mike CE were used as a blowing agent. Comparative Example 4 involved the production of a multi-ribbed V-belt, which, apart from these substances, had the same compositions as those in Comparative Example 1. <Vergleichsbeispiel 5>

[0097] In the non-crosslinked rubber composition used in Comparative Example 1, 42 parts by mass of ISAF carbon black were used. 80 parts by mass of HI-ZEX MILLION 630M polyethylene particles were used. No montmorillonite was included. 2.7 parts by mass of hollow particles were used. Comparative Example 5 was a multi-ribbed V-belt that, apart from these substances, had the same composition as that in Comparative Example 1. [Table 1] Example Material type Material name 1 2 3 4 5 6 7 8 9 10 11 12 13 polymer EPDM 100 100 100 100 100 100 100 100 100 100 100 100 100 soot ISAF 2 2 2 2 2 2 12 2 2 2 2 2 HAF 2 Polyethylene particles HI-ZEX MILLION 240S 50 50 70 100 80 80 80 50 50 50 HI-ZEX MILLION 630M 80 80 80 inorganic filler Silicon dioxide ULTRASIL VN3 40 40 40 40 40 40 30 40 40 60 50 40 30 Montmorillonite Hotaka 40 Ben-Gel HVP Ben-Gel Blight 11 40 40 40 40 40 40 Ben-Gel W-100 20 20 Calcium carbonate ACTIFORT 700 5 5 5 5 5 5 5 5 5 5 5 5 5 Hollow particles EM403 2,6 2,6 2,6 3,1 2,6 2,7 2,7 2,6 2,7 2,7 2,7 2,7 2,7 propellant Cell-Mike CE 7,30 7,30 Vulcanization aid Stearic acid Zinc oxide Group 3 0,5 0,5 0,5 0,5 0,5 0,5 0,5 0,5 0,5 0,5 0,5 0,5 0,5 5,0 5,0 5,0 5,0 5,0 5,0 5,0 5,0 5,0 5,0 5,0 5,0 5,0 Vulcanizing agent PEROXYMON F40 8,0 8,0 8,0 8,0 8,0 8,0 8,0 8,0 8,0 8,0 8,0 8,0 8,0 Co-networker Hi-Cross M / TMP 2,0 2,0 2,0 2,0 2,0 2,0 2,0 2,0 2,0 2,0 2,0 2,0 2,0 total phr 262,4 262,4 275,1 305,6 265,1 285,2 285,2 265,1 285,2 265,2 225,2 215,2 205,2 phr inorganic filler + polyethylene particles 135 135 155 185 145 165 155 145 165 145 105 95 85 Voltage in case of abnormal noise development (N / 6 ribs) no no no no no no no no no no no 270 N temporarily 440 N temporarily [Table 2] Comparative example Material type Material name 1 2 3 4 5 polymer EPDM 100 100 100 100 100 soot ISAF 22 42 42 42 42 HAF Polyethylene particles HI-ZEX MILLION 240S 20 20 30 50 HI-ZEX MILLION 630M 80 inorganic filler Silicon dioxide ULTRASIL VN3 20 Montmorillonite Hotaka 40 Ben-Gel HVP 40 Ben-Gel Blight 11 20 30 Ben-Gel W-100 Calcium carbonate ACTIFORT 700 5 Hollow particles EM403 2,6 2,9 2,7 2,6 2,7 propellant Cell-Mike CE 7,30 Vulcanization aid Stearic acid Zinc oxide Group 3 0,5 0,5 0,5 0,5 0,5 5,0 5,0 5,0 5,0 5,0 Vulcanizing agent PEROXYMON F40 8,0 8,0 8,0 8,0 8,0 Co-networker Hi-Cross M / TMP 2,0 2,0 2,0 2,0 2,0 total phr 200,1 220,4 235,2 247,4 240,2 phr inorganic filler + polyethylene particles 60 60 75 80 80 Voltage in case of abnormal noise development (N / 6 ribs) 1250 N 990 N 690 N 1120 N 1330 N (Test evaluation procedure)

[0098] Fig. Figure 17 shows an arrangement of belts in a belt running test device 40.

[0099] The belt running test device 40 comprises: a zinc-coated drive pulley 41, which is a ribbed pulley having a diameter of 140 mm and is provided in a lowest position; a first output pulley 42 (an air conditioning compressor pulley), which is a ribbed pulley having a diameter of 100 mm and is provided in a position to the right and above the drive pulley 41; and a second output pulley 43 (an alternator pulley), which is a ribbed pulley having a diameter of 60 mm and is provided in a position to the left and above the drive pulley 41 and the first output pulley 42, and further comprises an idler pulley 44, which is a flat pulley having a diameter of 95 mm and is provided to the left of the first output pulley 42.The belt running test device 40 is designed such that a multi-ribbed belt B is wound onto the respective pulleys in such a way that its wedge-shaped ribs come into contact with the drive pulley 41 and the first and second driven pulleys 42 and 43 respectively, which are ribbed pulleys, and its back side comes into contact with the idler pulley 44, which is a flat pulley.

[0100] In Examples 1 to 13 and Comparative Examples 1 to 5, the multi-ribbed V-belt was tested on the belt running tester 40 for abnormal noise generation (whether abnormal noise generation occurred) when the belt was wet. For these tests, a multi-ribbed V-belt under test was wound around the pulleys of the belt running tester 40, and the idler pulley 44 was positioned so that the multi-ribbed V-belt was subjected to a predetermined tension. Loads were applied to the first output pulley 42 (1.5 MPa) and the second output pulley 43 (20 A). The drive pulley 41 was rotated at 750 ± 120 rpm at an ambient temperature of 25 °C to run the belt.Then, a section of the belt, starting from the point where the belt was wound around the drive pulley 41, was exposed to 10 ml of water to check whether there was any abnormal noise development on the belt exhibiting the relevant tension.

[0101] The tests were conducted with a belt tension ranging from 1300 N to 200 N. It should be noted that the belt tension was adjusted by changing the bearing position of the idler pulley 44. Therefore, precisely adjusting the belt tension by 100 N proved difficult. Actual tests were performed from above 1300 N to below 200 N. In other words, the tests began with a tension above 1300 N. If no abnormal noise occurred, the position of the idler pulley 44 was changed to reduce the tension by approximately 100 N, and the presence or absence of abnormal noise when the belt was exposed to water was checked. The belt tension was gradually reduced. If abnormal noise occurred, the tension was recorded at the time the noise was heard. (As described above, the tension was difficult to adjust precisely.)Therefore, the voltage was not determined by the 100 N. (Test results)

[0102] Tables 1 and 2 show the results. If a tension value is given on its own, abnormal noise occurred when the belt tension was reduced to that value. The term "temporary," given alongside a value, means that abnormal noise occurred only briefly when the belt was running at the reduced tension and after being exposed to water; however, the abnormal noise disappeared when the belt continued to run. Furthermore, the term "none" means that no abnormal noise occurred across the entire belt tension range from 1300 N to 200 N.

[0103] In comparative examples 1 to 5, where the inorganic filler and polyethylene particles comprised a total proportion of 60 to 80 parts by mass, the abnormal noise persisted for more than just a momentary occurrence until the belt tension was reduced to 200 N (from 690 N to 1330 N). In example 13, however, where the total proportion was 85 parts by mass, abnormal noise occurred only temporarily at a belt tension of 440 N. Thus, the abnormal noise was reduced in the wet condition. In example 12, where the total proportion was 95 parts by mass, abnormal noise occurred only temporarily at a belt tension of 270 N. Thus, the abnormal noise was further reduced in the wet condition.In the case of examples 1 to 11, where the total mass fraction ranges from 105 to 185 parts by mass, no abnormal noise occurs across the entire belt tension range of 1300 N to 200 N. The abnormal noise is sufficiently reduced. INDUSTRIAL APPLICABILITY

[0104] The present invention is applicable in the technical field of friction transmission belts. REFERENCE MARK LIST B Multi-ribbed belt, V-belt, flat belt (friction transmission belt) 11 compressed rubber layers 11a Surface rubber layer 17 inner rubber layer

Claims

[1] Friction transmission belt with a rubber layer forming a pulley contact surface, wherein the rubber layer comprises a rubber composition containing polyolefin particles and an inorganic filler, the inorganic filler comprises both silicon dioxide and montmorillonite or both silicon dioxide and calcium carbonate, in the rubber composition, a proportion of the polyolefin particles relative to 100 parts by mass of a rubber component is 50 parts by mass or more, and in the rubber composition, a proportion of the inorganic filler relative to 100 parts by mass of the rubber component is 35 parts by mass or more. [2] The friction transmission belt according to claim 1, wherein in the rubber composition, the total content of the polyolefin particles and the inorganic filler is 95 parts by mass or more based on 100 parts by mass of the rubber component. [3] The friction transmission belt according to claim 1, wherein in the rubber composition, the total content of the polyolefin particles and the inorganic filler is 105 parts by mass or more based on 100 parts by mass of the rubber component. [4] A friction transmission belt according to any one of claims 1 to 3, wherein the polyolefin particles are formed of ultra-high molecular weight polyethylene having a molecular weight of 500,000 or more. [5] The friction transmission belt according to claim 1, wherein in the rubber composition, a proportion of the silica is 30 parts by mass or more based on 100 parts by mass of the rubber component. [6] The friction transmission belt according to claim 1, wherein the rubber composition does not contain an adhesion promoter. [7] A friction transmission belt according to claim 1, wherein the inorganic filler contains at least Ca-montmorillonite. [8] A friction transmission belt according to claim 1, wherein the silica of the inorganic filler does not receive an adhesion-promoting treatment.

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