JP2009115199A - Friction transmission belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inhibit a noise owing to the slip caused when the belt section of a friction transmission belt covered with water is running. <P>SOLUTION: The friction transmission belt B is composed of a pulley contact portion 13 formed of a rubber composition in a belt body 10. The rubber composition to form the pulley contact portion 13 is composed of ethylene-α-olefin elastomer as a base rubber, in which 100 parts by mass of the base rubber are blended with 10-50 mass parts of calcium carbonate and carbon black of 300 cm<SP>3</SP>/100g or more DBP oil absorption as measured based on A method in JIS K 6217-4. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a friction transmission belt in which a belt main body includes a pulley contact portion formed of a rubber composition.

  A friction transmission belt in which a pulley contact portion of a belt body is formed of a rubber composition, such as a V belt or a V-ribbed belt, is widely used for automotive accessory driving applications and the like. And it is a well-known technique to mix | blend carbon black with the rubber composition which comprises this pulley contact part.

Patent Document 1 discloses a transmission belt having a transmission surface formed of a rubber composition in which 50 to 100 parts by mass of carbon black is blended with 100 parts by mass of rubber, and an ethylene-α-olefin copolymer is added to a base rubber. polymer rubber is used, the carbon black, those nitrogen adsorption specific surface area 45~80m ² / g and DBP oil absorption of 120 cm ^3/100 g or more high structure carbon is contained in 20 parts by mass or more with respect to 100 parts by mass of the rubber Is disclosed.

  By the way, in a belt transmission system driven by an automobile accessory, it is known that a phenomenon called stick slip occurs when the belt gets wet, and a slip noise is generated due to slip between the belt and the pulley. Since such slip noise causes noise, various countermeasures have been studied.

  For example, Patent Document 2 discloses a transmission belt having a transmission surface formed by a rubber composition containing an inorganic filler, and the inorganic filler reacts with a hydrophilic inorganic substance having a hydroxyl group or a water molecule or water. A hydrophilic inorganic filler using a hydrophilic inorganic precursor that becomes a hydrophilic inorganic substance is used, and the rubber composition contains 5 parts by weight or more of the hydrophilic inorganic filler with respect to 100 parts by weight of the rubber. Have been disclosed.

  Patent Document 3 discloses a transmission belt in which short fibers are mixed in at least a part of a belt-constituting rubber portion, and an ethylene-propylene-diene rubber having an iodine value of 3 or more and less than 40 is used as the rubber. A single nylon short fiber is used, and the blending amount is set to 20 to 50 parts by mass with respect to 100 parts by mass of rubber.

  Patent Document 4 discloses a V-ribbed belt in which a compressed rubber layer that is a pulley contact portion is composed of a rubber composition in which 3 to 25 parts by mass of nylon resin powder is blended with 100 parts by mass of rubber.

  Patent Document 5 discloses a V-ribbed belt in which a compressed rubber layer that is a pulley contact portion is composed of a rubber composition in which 1 to 15 parts by mass of a porous acrylic short fiber is blended with respect to 100 parts by mass of rubber. Yes.

  In Patent Document 6, an ethylene-α-olefin elastomer is used as a base rubber, the total addition amount of short fibers is 10 to 40 parts by mass with respect to 100 parts by mass of the base rubber, and aramid fibers are added as short fibers to the total addition of short fibers. There is disclosed a V-ribbed belt in which a compression rubber layer is formed with a rubber composition containing 35 to 100% by mass of an amount and adding 25 to 55 parts by mass of carbon black.

  In Patent Document 7, the compression rubber layer which is a pulley contact part is 1 to 15 parts by mass of ultrashort fibers having a fiber length of 0.1 to 1.0 mm and a moisture content of 6 to 20% with respect to 100 parts by mass of rubber. A V-ribbed belt composed of a compounded rubber composition is disclosed.

  In Patent Document 8, at least each rib portion of the V-ribbed belt has a cotton short fiber, and a nylon short fiber having an elastic modulus intermediate between the elastic modulus of the main rubber constituting each rib portion and the elastic modulus of the cotton short fiber, The inclusion of zinc powder is disclosed.

  Patent Document 9 discloses a V-ribbed belt in which a para-aramid short fiber is contained in a compressed rubber layer, the para-aramid short fiber protrudes from a side surface of the rib, and the protruding portion of the para-aramid short fiber is fibrillated. Is disclosed.

  In Patent Document 10, the compressed rubber layer contains short cotton fibers and para-aramid short fibers and protrudes from the rib side surfaces, and the protruding para-aramid short fibers are fibrillated. A V-ribbed belt is disclosed in which the content of short aramid fibers is 10 to 40 parts by weight of cotton short fibers and 5 to 10 parts by weight of para-aramid short fibers with respect to 100 parts by weight of rubber in the compressed rubber layer.

Patent Document 11 discloses that at least a part of short fibers embedded in a V-shaped rib forming a compressed rubber layer is 5 to 20 parts by weight of a para-aramid fiber with respect to 100 parts by weight of rubber, and the V-shaped rib. There is disclosed a V-ribbed belt in which para-aramid short fibers projecting from the side surface of the fiber are fibrillated.
JP 2006-266356 A JP 2007-120526 A Japanese Patent Laid-Open No. 2004-257459 Japanese Patent Laid-Open No. 2004-232743 JP 2004-176904 A JP 2004-150524 A JP 2004-125012 A JP 2003-202055 A Japanese Patent Laid-Open No. 2001-254882 JP 2001-165244 A JP 7-151191 A

  An object of the present invention is to suppress a slip noise during running of a wet friction transmission belt.

The friction transmission belt of the present invention includes a pulley contact portion formed of a rubber composition in the belt body,
The rubber composition for forming the pulley contact portion uses an ethylene-α-olefin elastomer as a base rubber, 10 to 50 parts by mass of calcium carbonate with respect to 100 parts by mass of the base rubber, and method A in JIS K 6217-4 and carbon black DBP oil absorption amount is 300 cm ^3/100 g or more measured according to, characterized in that is blended.

According to the present invention, the rubber composition forming the pulley contact portion uses an ethylene-α-olefin elastomer as a base rubber, and 10 to 50 parts by mass of calcium carbonate and DBP oil absorption amount with respect to 100 parts by mass of the base rubber. There the carbon black is 300 cm ^3/100 g or more, since is blended, generation of slip sound at the time even belt running if you Himizu is suppressed by their interaction.

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

  FIG. 1 shows a V-ribbed belt B (friction transmission belt) according to this embodiment. The V-ribbed belt B is preferably used for, for example, an automotive accessory driving application, and is formed to have a belt circumferential 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. Yes.

  The V-ribbed belt B includes a V-ribbed belt main body 10 configured as a double layer of an adhesive rubber layer 11 on the belt outer peripheral side and a compression rubber layer 12 on the belt inner peripheral side, and the belt outer peripheral side of the V-ribbed belt main body 10. A reinforcing cloth 17 is stuck on the surface. Further, a core wire 16 is embedded in the adhesive rubber layer 11 so as to form a spiral having a pitch in the belt width direction.

  The adhesive rubber layer 11 is formed in a band shape having a horizontally long cross section, and is formed to have a thickness of 1.0 to 2.5 mm, for example. The adhesive rubber layer 11 is formed of a rubber composition in which various compounding agents are blended with a base rubber. Examples of the base rubber of the rubber composition constituting the adhesive rubber layer 11 include ethylene-α-olefin elastomers such as ethylene / propylene rubber (EPR) and ethylene propylene diene monomer rubber (EPDM), chloroprene rubber (CR), chloro Examples thereof include sulfonated polyethylene rubber (CSM) and hydrogenated acrylonitrile rubber (H-NBR). Of these, ethylene-α-olefin elastomers are preferred from the viewpoint of environmental considerations and performance such as wear resistance and crack resistance. Examples of the compounding agent include a crosslinking agent (for example, sulfur, organic peroxide), an anti-aging agent, a processing aid, a plasticizer, a reinforcing material such as carbon black, a filler, and the like. The rubber composition for forming the adhesive rubber layer 11 is obtained by heating and pressurizing an uncrosslinked rubber composition in which a compounding agent is blended with a base rubber and kneaded so as to be crosslinked with a crosslinking agent.

  The compression rubber layer 12 is provided such that a plurality of V ribs 13 constituting a pulley contact portion hang down to the belt inner peripheral side. Each of the plurality of V ribs 13 is formed in a ridge having a substantially inverted triangular cross section extending in the belt length direction, and arranged in parallel in the belt width direction. Each V rib 13 is formed, for example, with a rib height of 2.0 to 3.0 mm and a width between base ends of 1.0 to 3.6 mm. Moreover, the number of ribs is 3-6, for example (in FIG. 1, the number of ribs is 6).

  The compressed rubber layer 12 is formed of a rubber composition in which various compounding agents are blended with an ethylene-α-olefin elastomer that is a base rubber. Examples of the ethylene-α-olefin elastomer of the base rubber constituting the compressed rubber layer 12 include ethylene / propylene rubber (EPR) and ethylene propylene diene monomer rubber (EPDM). Examples of the compounding agent include cross-linking agents (for example, sulfur and organic peroxides), anti-aging agents, processing aids, plasticizers, reinforcing materials such as calcium carbonate and carbon black, fillers, ultrahigh molecular weight polyethylene particles ( Weight average molecular weight of 1 million or more), short fibers 14 and the like. The rubber composition for forming the compressed rubber layer 12 is obtained by heating and pressurizing an uncrosslinked rubber composition in which a compounding agent is blended with a base rubber and kneaded so as to be crosslinked with a crosslinking agent.

The rubber composition forming the compression rubber layer 12 is carbon black is blended, also in its carbon black, DBP oil absorption is measured according to the method A in JIS K 6217-4 is 300 cm ^3/100 g Carbon black as described above is included. Further, the carbon black preferably contains FEF carbon black.

  The total content of carbon black is preferably 1 to 120 parts by mass, and more preferably 20 to 90 parts by mass with respect to 100 parts by mass of the base rubber.

Carbon black DBP oil absorption amount is 300 cm ^3/100 g or more, preferably a primary particle diameter of 15 to 80 nm, more preferably from 20 to 50 nm, also BET specific surface area of 400 meters ² / g It is preferable that it is above, and it is more preferable that it is 600 m ² / g or more. Carbon black DBP oil absorption amount is 300 cm ^3/100 g or more, from the viewpoint of preventing the charging of the belt, is preferably a conductive carbon black. DBP oil absorption amount is 300 cm ^3/100 g or more carbon black is preferably the total content with respect to the base rubber 100 parts by weight is 1 to 50 parts by weight, more preferably 1 to 30 parts by weight.

  The total content of the FEF carbon black with respect to 100 parts by mass of the base rubber is preferably 1 to 120 parts by mass, and more preferably 20 to 90 parts by mass.

  In addition to carbon black, channel black; furnace black such as SAF, ISAF, N-339, HAF, N-351, MAF, SRF, GPF, ECF, N-234; thermal black such as FT, MT; acetylene Black etc. may be contained.

The rubber composition forming the compressed rubber layer 12 is mixed with calcium carbonate. The calcium carbonate preferably has a particle size of 0.001 to 20 μm, more preferably 0.001 to 10 μm, and a specific surface area of 0.1 to 30 m ² / g, preferably 1 more preferably ~30m is ² / g, further preferably DOP absorption is 10 to 100 ml / 100 g, more preferably from 10 to 80 ml / 100 g, also, pH is 7.5 to 9 .8 is preferable, and 8.0 to 9.5 is more preferable. As for calcium carbonate, content with respect to 100 mass parts of base rubbers is 10-50 mass parts, and it is more preferable that it is 10-30 mass parts.

As described above, in the V-ribbed belt B according to the present embodiment, the rubber composition forming the compressed rubber layer 12 including the V-rib 13 that is the pulley contact portion uses the ethylene-α-olefin elastomer as the base rubber, and the base rubber. calcium carbonate 10 to 50 parts by weight per 100 parts by weight, and carbon black DBP oil absorption amount is 300 cm ^3/100 g or more, since is blended, belt running even when Himizu by their interaction Generation of slip noise at the time is suppressed.

  The short fibers 14 blended in the rubber composition forming the compressed rubber layer 12 are provided so as to be oriented in the belt width direction. A part of the short fibers 14 is exposed on the pulley contact surface, that is, the surface of the V rib 13. The short fibers 14 exposed on the surface of the V rib 13 may protrude from the surface of the V rib 13.

  Examples of the short fibers 14 include nylon short fibers, vinylon short fibers, cotton short fibers, polyester short fibers, and aramid short fibers. In addition, the short fiber 14 may be comprised by single type, and may be comprised by multiple types.

  The short fibers 14 preferably have a content of 1 to 30 parts by mass with respect to 100 parts by mass of the base rubber. For example, the short fibers 14 have a length of 0.2 to 5.0 mm, preferably 3.0 mm or less, and more preferably 1.0 mm or less. The short fiber 14 has a fiber diameter of 10 to 50 μm, for example. The short fibers 14 are obtained by, for example, cutting long fibers that have been subjected to an adhesion treatment to be heated after being immersed in resorcin / formalin / latex aqueous solution (hereinafter referred to as “RFL aqueous solution”) into a predetermined length along the length direction. Manufactured.

  The compressed rubber layer 12 may have a configuration that does not include the short fibers 14, or may have a configuration in which the short fibers are attached to the surface of the V rib 13 by flocking.

  The adhesive rubber layer 11 and the compressed rubber layer 12 may be formed of separate rubber compositions or may be formed of the same rubber composition.

  The reinforcing cloth 17 is composed of, for example, a woven cloth 17 'woven in plain weave, twill weave, satin weave or the like formed of yarn such as cotton, polyamide fiber, polyester fiber, and aramid fiber. In order to give the reinforcing cloth 17 adhesion to the V-ribbed belt main body 10, an adhesive treatment in which it is immersed in an RFL aqueous solution and heated before molding and / or a surface of the V-ribbed belt main body 10 is coated with rubber paste. Adhesive treatment for drying is applied. In addition, the belt outer peripheral side surface portion may be made of a rubber composition instead of the reinforcing cloth 17. Further, the reinforcing cloth 17 may be formed of a knitted fabric. Furthermore, you may be comprised with the rubber composition which the belt back surface was exposed, without providing the reinforcement cloth 17. FIG.

  The core wire 16 is composed of a twisted yarn 16 'such as a polyester fiber (PET), a polyethylene naphthalate fiber (PEN), an aramid fiber, or a vinylon fiber. In order to give the core wire 16 adhesion to the V-ribbed belt main body 10, an adhesive treatment for heating after being immersed in an RFL aqueous solution before molding and / or an adhesive treatment for drying after being immersed in rubber paste is performed. .

  Next, a method for manufacturing the V-ribbed belt B will be described with reference to FIG.

  In the manufacture of the V-ribbed belt B, an inner die having a molding surface for forming the back surface of the belt in a predetermined shape on the outer periphery and a rubber sleeve having a molding surface for forming the inner side of the belt in a predetermined shape on the inner periphery are used.

  First, after the outer periphery of the inner mold is covered with a woven cloth 17 ′ that becomes the reinforcing cloth 17, an uncrosslinked rubber sheet 11 b ′ for forming the outer portion 11 b of the adhesive rubber layer 11 is wound thereon.

  Next, a twisted yarn 16 'serving as a core wire 16 is spirally wound thereon, and then an uncrosslinked rubber sheet 11a' for forming the inner portion 11a of the adhesive rubber layer 11 is wound thereon, and further On top of this, an uncrosslinked rubber sheet 12 ′ for forming the compressed rubber layer 12 is wound. At this time, as the uncrosslinked rubber sheet 12 ′ for forming the compressed rubber layer 12, a blend of short fibers 14 oriented in a direction orthogonal to the winding direction is used. In this uncrosslinked rubber sheet 12 ′, 30 parts by mass or less of short fibers 14 are blended with respect to 100 parts by mass of the base rubber, and among these short fibers 14, vinylon short fibers are 1 part by mass or more with respect to 100 parts by mass of the base rubber. It is a blended one.

  After that, cover the molded body on the inner mold with a rubber sleeve, set it in the molding pot, heat the inner mold with high-temperature steam, etc., and press the rubber sleeve radially inward by applying high pressure To do. At this time, the base rubber flows and the crosslinking reaction proceeds, and in addition, the adhesion reaction of the twisted yarn 16 ′ and the woven fabric 17 ′ to the rubber also proceeds. And thereby, a cylindrical belt slab (belt main body precursor) is shape | molded.

  Then, after removing the belt slab from the inner mold and dividing the belt slab into several pieces in the length direction, the outer periphery of each is polished and cut to form the V rib 13, that is, the pulley contact portion. At this time, the short fibers 14 exposed on the pulley contact surface may be protruded from the pulley contact surface, that is, the V rib 13 surface.

  Finally, the belt slab, which is divided and formed with the V ribs 13 on the outer periphery, is cut into a predetermined width and turned upside down to obtain the V-ribbed belt B.

  Next, an auxiliary machine drive belt transmission device 30 provided in the engine room of an automobile using the V-ribbed belt B will be described.

  FIG. 3 shows a pulley layout of the accessory drive belt transmission 30. The accessory drive belt transmission device 30 is of a serpentine drive type wound around six pulleys of four rib pulleys and two flat pulleys.

  The layout of the auxiliary drive belt transmission device 30 includes a power steering pulley 31 at the uppermost position, an AC generator pulley 32 disposed below the power steering pulley 31, and a flat pulley disposed at the lower left of the power steering pulley 31. Tensioner pulley 33, flat pulley water pump pulley 34 disposed below tensioner pulley 33, crankshaft pulley 35 disposed on the lower left side of tensioner pulley 33, and disposed on the lower right side of crankshaft pulley 35. The air conditioner pulley 36 is configured. Among these, all except the tensioner pulley 33 and the water pump pulley 34 which are flat pulleys are rib pulleys. Then, the V-ribbed belt B is wound around the power steering pulley 31 so that the V-rib 13 side contacts, and then wound around the tensioner pulley 33 so that the back surface of the belt contacts, and then the V-rib 13 side contacts. Are wound around the crankshaft pulley 35 and the air conditioner pulley 36 in turn, further wound around the water pump pulley 34 so that the back of the belt contacts, and then wound around the AC generator pulley 32 so that the V-rib 13 side contacts. Finally, it is provided so as to return to the power steering pulley 31.

  In the auxiliary drive belt transmission device 30 configured as described above, since the V-ribbed belt B is used, the generation of slip noise during belt running is suppressed even when it is wet. Moreover, even if the pulley material is aluminum or galvanized iron, the effect can be obtained.

  In this embodiment, the V-ribbed belt B is used. However, the present invention is not particularly limited to this. If the pulley contact portion of the belt body is a friction transmission belt formed of a rubber composition, FIG. 4 may be a flat belt shown in FIG. 4 (b), or a double V-ribbed belt having a rib portion on the back side shown in FIG. 4 (c).

  In the present embodiment, the entire compressed rubber layer 12 is formed of a single rubber composition. However, the present invention is not particularly limited to this, and at least the pulley contact portion on the surface of the V rib 13 is formed of the rubber composition. It only has to be done.

  Moreover, in this embodiment, although it was set as the auxiliary machine drive belt transmission device 30 which has four rib pulleys, if it is three or more including a pair of rib pulleys, it will not be limited to this, It has many more rib pulleys It may be a thing.

(Test evaluation belt)
V-ribbed belts of Examples 1 to 5 and Comparative Examples 1 to 4 below were produced. Each configuration is also shown in Tables 1 and 2.

<Example 1>
The base rubber is ethylene propylene diene monomer rubber (EPDM) (trade name: EP24 manufactured by JSR Corporation), and stearic acid (trade name: stearic acid 50S manufactured by Shin Nippon Chemical Co., Ltd.) 0.25 with respect to 100 parts by mass of the base rubber. Parts by mass, 5 parts by mass of zinc oxide (trade name: zinc oxide 3 types, manufactured by Sakai Chemical Industry Co., Ltd.), 2.5 parts by mass of anti-aging agent (product name: NOCRACK 224, manufactured by Ouchi Shinsei Chemical Co., Ltd.), FEF carbon black (Tokai carbon Corporation, trade name: SEAST SO, DBP oil absorption 115cm ³ / 100g) 50 parts by weight of conductive carbon black (Lion Corporation, trade name: Ketjen black EC300J, DBP oil absorption of 360 cm ^3/100 g), calcium carbonate (Maruo Product name: MSK-A, manufactured by Calcium Co., Ltd. 10 parts by mass of Nmpar 2280), 4 parts by mass of a cross-linking agent (Nippon Yushi Co., Ltd., trade name: Park Mill D), and 10 parts by mass of nylon short fiber (trade name: nylon 6,6 type T-5 fiber length 1 mm, manufactured by Asahi Kasei Co. A V-ribbed belt formed with a compressed rubber layer was prepared from a sheet-like uncrosslinked rubber composition obtained by blending and kneading with a closed kneader and rolling with an open roll. The DBP oil absorption of FEF carbon black and conductive carbon black is measured according to the method A in JIS K 6217-4.

  The adhesive rubber layer is made of an EPDM rubber composition, and the core wire is made of polyester fiber (PET) twisted yarn made of RFL. The belt circumference is 1210 mm and the belt width is 21 without using a reinforcing cloth. The belt thickness was 4.3 mm and the number of ribs was six.

<Example 2>
A V-ribbed belt having the same configuration as in Example 1 was prepared except that the amount of calcium carbonate in the uncrosslinked rubber composition forming the compressed rubber layer was 20 parts by mass with respect to 100 parts by mass of the base rubber. Example 2 was adopted.

<Example 3>
A V-ribbed belt having the same configuration as in Example 1 was prepared except that the amount of calcium carbonate in the uncrosslinked rubber composition forming the compressed rubber layer was 30 parts by mass with respect to 100 parts by mass of the base rubber. Example 3 was adopted.

<Example 4>
A V-ribbed belt having the same configuration as in Example 1 was prepared except that the amount of calcium carbonate in the uncrosslinked rubber composition forming the compressed rubber layer was 40 parts by mass with respect to 100 parts by mass of the base rubber. Example 4 was adopted.

<Example 5>
A V-ribbed belt having the same configuration as in Example 1 was prepared except that the amount of calcium carbonate in the uncrosslinked rubber composition forming the compressed rubber layer was 50 parts by mass with respect to 100 parts by mass of the base rubber. Example 5 was adopted.

<Comparative Example 1>
Implemented except that the amount of FEF carbon black in the uncrosslinked rubber composition forming the compressed rubber layer is 60 parts by mass with respect to 100 parts by mass of the base rubber, and that conductive carbon black and calcium carbonate are not compounded. A V-ribbed belt having the same configuration as in Example 1 was produced, and this was designated as Comparative Example 1.

<Comparative example 2>
A V-ribbed belt having the same configuration as in Example 1 was prepared except that the amount of calcium carbonate in the uncrosslinked rubber composition forming the compressed rubber layer was 5 parts by mass with respect to 100 parts by mass of the base rubber. It was set as Comparative Example 2.

<Comparative Example 3>
A V-ribbed belt having the same configuration as in Example 1 was prepared except that the amount of calcium carbonate in the uncrosslinked rubber composition forming the compressed rubber layer was 60 parts by mass with respect to 100 parts by mass of the base rubber. It was set as Comparative Example 3.

<Comparative example 4>
Example 1 except that the amount of FEF carbon black in the uncrosslinked rubber composition forming the compressed rubber layer is 60 parts by mass with respect to 100 parts by mass of the base rubber, and no conductive carbon black is added. A V-ribbed belt having the same configuration was produced and used as Comparative Example 4.

(Test evaluation method)
<Rubber hardness test>
For each of Examples 1 to 5 and Comparative Examples 1 to 4, a rubber sheet was produced by molding a sheet-like uncrosslinked rubber composition forming a compressed rubber layer with an electric heat press, and in accordance with JIS K6253. The rubber hardness was measured by durometer type A using the rubber sheet.

<Tensile test>
For each of Examples 1 to 5 and Comparative Examples 1 to 4, a rubber sheet was produced by molding a sheet-like uncrosslinked rubber composition forming a compressed rubber layer with an electric heat press, and in accordance with JIS K6253. The dumbbell-shaped No. 3 was punched out from the rubber sheet, and a tensile test was conducted using it as a test piece to measure the tensile strength and elongation at break. Note that the dumbbell-shaped No. 3 was punched so that the length direction was perpendicular to the orientation direction of the short fibers.

<Heat-resistant bending test>
FIG. 5 shows a pulley layout of the belt running test machine 50 for heat-resistant bending test.

  This heat-resistant bending test belt running test machine 50 includes four driven rib pulleys 51 each having a pulley diameter of 50 mm, which are provided in a rectangular arrangement in the vertical and horizontal directions, and pulleys provided in a square arrangement in the vertical and horizontal directions. Four driven flat pulleys 52 having a diameter of 50 mm and driving rib pulleys 53 having a pulley diameter of 60 mm are provided. The upper two driven flat pulleys 52 are provided at the intermediate positions in the vertical direction of the upper and lower driven rib pulleys 51 in a region surrounded by the four rectangular driven rib pulleys 51 arranged in a rectangle. 52 is provided below the lower driven rib pulley 51. The drive rib pulley 53 is provided below the lower driven flat pulley 52 at the intermediate position in the left-right direction of the driven rib pulley 51 and the driven flat pulley 52. Neither the driven rib pulley 51 nor the driven flat pulley 52 is given a rotational load.

  For each of the V-ribbed belts B of Examples 1 to 5 and Comparative Examples 1 to 4, the driven rib pulley is such that the V-rib of the compression rubber layer is in contact with the driven rib pulley 51 and the reinforcing cloth is in contact with the driven flat pulley 52. 51 and the driven flat pulley 52 are alternately wound, and then wound around the drive rib pulley 53 so that the V-rib of the compressed rubber layer is in contact, and then downward on the drive rib pulley 53 so that a belt tension of 800 N is applied. A load was applied, and the drive rib pulley 53 was rotated at a rotational speed of 3300 rpm to run the belt. At this time, the ambient temperature is raised to 100 ° C., the state is maintained for 50 hours, the temperature is increased to 105 ° C., and the state is maintained for 50 hours. For 50 hours was repeated until the ambient temperature reached 130 ° C., and after 300 hours when the ambient temperature reached 130 ° C., temperature control was performed to maintain 130 ° C.

  The belt running is periodically stopped, the V-ribbed belt B is visually inspected, the belt running time until a crack is generated is recorded as the heat-resistant bending running life, and the heat-resistant bending running life of Comparative Example 1 is set as 100. The value was calculated.

<Electrical resistance test>
FIG. 6 shows an electrical resistance measuring device 60.

  The electrical resistance measuring device 60 includes a pair of terminals 63 provided on a base 61 and each having a brass base 62 attached thereto, and each of the pair of terminals 63 is electrically connected to an electrical resistance meter 64. It is connected. The distance between the brass bases 62 attached to the pair of terminals 63 is 100 mm. Further, a 1 kg weight 65 is provided for each brass base 62.

  About each V-ribbed belt B of Examples 1 to 5 and Comparative Examples 1 to 4, a voltage of 500 V is applied between the terminals 63 in a state of being spanned between a pair of brass bases 62 and sandwiched between the brass bases 62 by weights 65, respectively. To measure the electrical resistance. Further, the belt was run for 120 hours at an ambient temperature of 130 ° C. using the belt running test machine for heat-resistant bending test shown in FIG. 5, and the electrical resistance was measured in the same manner.

<Abrasion resistance test>
FIG. 7 shows the pulley layout of the belt running test machine 70 for wear resistance test.

  The wear resistance test belt running test machine 70 includes a drive rib pulley 71 and a driven rib pulley 72, each having a pulley diameter of 60 mm, provided on the left and right sides. A rotational load of 3.8 kW is applied to the driven rib pulley 72.

  After measuring the mass of each V-ribbed belt B of Examples 1 to 5 and Comparative Examples 1 to 4, it was wound around the drive rib pulley 71 and the driven rib pulley 72 so that the V-ribs of the compression rubber layer were in contact with each other, and then 1177N The drive rib pulley 71 was loaded with a dead weight laterally so that the belt tension was applied, and the drive rib pulley 71 was rotated at a rotational speed of 3500 rpm to run the belt for 24 hours, and the mass was measured again after running the belt. .

  The wear rate was calculated by dividing the weight loss before and after running the belt by the mass before running the belt. The wear rate of Comparative Example 1 was taken as 100, and the relative value was calculated as wear resistance.

<Water injection noise test>
FIG. 8 shows a pulley layout of the water injection noise test belt running test machine 80.

  The water injection noise test belt running test machine 80 includes a first driven rib pulley 81 having a pulley diameter of 60 mm attached to the generator, a second driven rib pulley 82 having a pulley diameter of 75 mm provided obliquely below and to the right of the first driven rib pulley 82. A driven flat pulley 83 having a pulley diameter of 75 mm provided diagonally to the left of the driven rib pulley 81 and diagonally to the left of the second driven rib pulley 82, and to the left of the second driven rib pulley 82 and diagonally to the left of the driven flat pulley 83. And a drive rib pulley 84 having a pulley diameter of 140 mm. Neither the second driven rib pulley 82 nor the driven flat pulley 83 is given a rotational load.

  For each of the V-ribbed belts B of Examples 1 to 5 and Comparative Examples 1 to 4, the V-ribs of the compression rubber layer are in contact with the first and second driven rib pulleys 81 and 82 and the drive rib pulley 84. After wrapping the reinforcing fabric around 83, the test machine is set so that the belt tension of 49.0N / 1 rib is applied, and the drive rib pulley 84 is rotated at a rotational speed of 800 rpm. The belt was run. At this time, a rotational load was applied to the first driven rib pulley 81 so that the generator could generate 60A.

  Noise measurement was performed using a noise meter at the position immediately after the first lower right side of the first driven rib pulley 81. Subsequently, the belt travel was once stopped, 500 ml of water was poured onto the V-ribbed belt B at the position immediately before the drive rib pulley 84 was wound, and then the belt traveled again. Similarly, noise measurement was performed using a noise meter. .

  Even if the difference in sound volume between before and after applying water is less than 1 dB or exceeds 1 dB, it is evaluated as “no abnormal sound” and the difference in sound volume exceeds 1 dB. In addition, the case of continuing for more than 1 second was evaluated as “abnormal sound generation”.

(Test evaluation results)
Tables 3 and 4 show the test evaluation results.

  According to these results, it can be seen that Examples 1 to 5 have all of high heat-resistant flexibility, low electrical resistance, and low wear, and can suppress the generation of slip noise when wet. . On the other hand, Comparative Examples 1 and 2 generate slip noise when wet, and Comparative Example 3 suppresses the generation of slip noise when wet, but the wear resistance is low. Although the generation of slip noise during water is suppressed, it can be seen that the electrical resistance is high.

  The present invention is useful for a friction transmission belt in which a belt main body includes a pulley contact portion formed of a rubber composition.

It is a perspective view of a V-ribbed belt. It is explanatory drawing which shows the manufacturing method of V-ribbed belt. FIG. 6 is a layout diagram of pulleys of a belt drive device for driving auxiliary equipment. (A)-(c) is belt sectional drawing of other embodiment. It is a figure which shows the pulley layout of the belt running test machine for heat-resistant bending tests. It is a schematic diagram which shows an electrical resistance measuring apparatus. It is a figure which shows the pulley layout of the belt running test machine for abrasion resistance tests. It is a figure which shows the pulley layout of the belt running test machine for water injection noise tests.

Explanation of symbols

B V-ribbed belt (friction drive belt)
10 V-ribbed belt body 13 V-rib (pulley contact part)

Claims (5)

A friction transmission belt including a pulley contact portion formed of a rubber composition in a belt body,
The rubber composition for forming the pulley contact portion uses an ethylene-α-olefin elastomer as a base rubber, 10 to 50 parts by mass of calcium carbonate with respect to 100 parts by mass of the base rubber, and method A in JIS K 6217-4 friction transmission belt DBP absorption to be measured, characterized in that the carbon black is 300 cm ^3/100 g or more, it is formulated in accordance with. In the friction transmission belt according to claim 1,
The friction transmission belt, wherein the rubber composition forming the pulley contact portion is further blended with FEF carbon black. In the friction transmission belt according to claim 1 or 2,
Friction transmission belt, wherein the carbon black the DBP oil absorption amount is 300 cm ^3/100 g or more is an electrically conductive carbon black. In the friction transmission belt according to any one of claims 1 to 3,
A friction transmission belt, wherein the belt body is a V-ribbed belt body. The friction transmission belt according to any one of claims 1 to 4,
A friction transmission belt characterized in that it is used for driving automotive accessories.

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