JP2017227327A - Transmission belt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmission belt capable of achieving both of slidability and side pressure resistance (rigidity).SOLUTION: In a transmission belt 1 including a tension band 2, and a plurality of blocks 10 arranged substantially at equal intervals in a longitudinal direction of the tension band 2, and integrated with the tension band by being fitted, a frictional transmission surface of the block 10 is composed of a resin composition including a resin component, carbon fiber and graphenes. A ratio of the graphenes is about 0.5-10 mass% to the entire resin composition. A ratio of the graphenes to 100 pts.mass of carbon fiber is 1-30 pts.mass. An average particle diameter of the graphene is about 0.1-3 μm. The resin component may be a phenol resin. The carbon fiber may have an average fiber length of 100 μm or more, and an average fiber diameter of 5-15 μm. The carbon fiber may include polyacrylonitrile-based carbon fibber and pitch-based carbon fiber. The blocks may include an insert material.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a transmission belt used in a belt-type continuously variable transmission of an automobile or a motorcycle.

  2. Description of the Related Art Belt-type continuously variable transmissions that can improve operability during shifting, improve fuel consumption, and the like are known as transmissions in automobiles, motorcycles, and the like. As a V-belt (transmission belt) used in a belt-type continuously variable transmission, a rubber low-edge V-belt is known. However, in high-load transmission applications (for example, high displacement automobiles and scooters), friction transmission A V-belt is adopted, in which a large number of blocks whose surfaces (contact surfaces with pulleys) are made of resin are fitted and integrated with endless tension bands (center belts) at intervals in the belt length direction. ing. As this V-belt, a V-belt provided with a block in which a metal reinforcing material (insert material) is coated with a resin coating layer, or a block formed only with a resin layer without using a metal reinforcing material (insert material) is provided. V belts are widely used. Such a V-belt has a high degree of slidability against contact with the pulley (the heat generated by friction is small), as well as rigidity for both sides to withstand high side pressure from the pulley when it is run around a pulley. And wear resistance is required. Therefore, the resin components that make up the friction transmission surface are improved in mechanical properties such as rigidity and can be used even under conditions where the side pressure received from the pulley is high (improves the side pressure resistance and improves the transmission performance of the transmission belt. For the purpose of improving (improvement), carbon fiber, aramid fiber and other reinforcing fibers are blended, and an appropriate coefficient of friction is given (usually lowering the coefficient of friction) to improve slidability. In order to improve the above, a solid lubricant (friction coefficient reducing material) such as fluororesin, ultra high molecular weight polyethylene, graphite, carbon nanotube, molybdenum disulfide, metal soap and the like is blended.

  Japanese Patent Laying-Open No. 2004-239432 (Patent Document 1) discloses a V-belt including a block in which a portion facing a pulley groove side portion of a block body made of a gellarmin material is covered with a phenol resin layer. In the example of this document, as the phenol resin layer, 76 parts by weight of carbon short fibers and 11.3 parts by weight of graphite powder as a friction modifier with respect to 100 parts by weight of a mixed resin of phenol aralkyl resin and novolac phenol resin. The phenol resin layer in which is blended is manufactured.

  Japanese Patent Application Laid-Open No. 2011-236994 (Patent Document 2) includes a block in which a pulley contact surface of a metal reinforcing material formed of duralumin is covered with a resin coating layer, and the resin coating layer includes a carbon short fiber on a matrix resin. A V-belt formed of a carbon short fiber reinforced resin to which is added is disclosed. In the examples of this document, a carbon short fiber in which 72.5 parts by weight or 81 parts by weight of carbon short fibers and 17.5 parts by weight of graphite powder are blended with respect to 100 parts by weight of a phenol resin as a carbon short fiber reinforced resin material. A fiber reinforced resin material has been prepared.

  Japanese Patent Application Laid-Open No. 2008-208996 (Patent Document 3) discloses a block made of a resin composition containing 30 to 89% by mass of a thermoplastic resin, 10 to 60% by mass of a fiber reinforcing material, and 1 to 50% by mass of a friction reducing material. A V-belt is disclosed. In the example of this document, a polyamide composition containing 30% by mass of carbon fibers and 5 to 15% by mass of graphite as a fiber reinforcing material is prepared as a resin composition constituting the block.

  Japanese Patent Laying-Open No. 2008-157440 (Patent Document 4) discloses a V-belt including a block made of a thermoplastic resin composition containing 10 to 40% by mass of a fiber reinforcing material and 1 to 20% by mass of a friction reducing material. ing. In the example of this document, a block is prepared with a polyamide composition containing 30% by mass of carbon fibers, 10% by mass of a fluororesin or 5% by mass of ultrahigh molecular weight polyethylene as a fiber reinforcement.

  Japanese Patent Laying-Open No. 2003-322217 (Patent Document 5) discloses a V-belt including a block made of a synthetic resin material in which carbon nanotubes are blended and having no insert material embedded therein. In the examples of this document, a block formed of a polyamide composition containing 20 to 40% by mass of carbon nanotubes is more durable and wear-resistant than a block formed of a polyamide composition containing 20% by mass of carbon fibers. In addition, it is described that it has excellent moldability and low noise.

  However, in the block using the resin composition containing the solid lubricant (friction coefficient reducing material) used in these patent documents, although the slidability is improved, the solid lubricant (friction coefficient reducing material) There is a tendency that mechanical properties (rigidity) necessary for side pressure resistance are reduced and adhesion with a metal reinforcing material (insert material) is lowered. In particular, since slidability and side pressure resistance (rigidity) are in a trade-off relationship, conventional solid lubricants cannot achieve both slidability and side pressure resistance (rigidity).

JP-A-2004-239432 (Claims, paragraph [0025], Examples) JP 2011-236994 A (Claims, Examples) JP 2008-208996 A (Claim 1, Example) JP 2008-157440 A (Claim 1, Example) JP 2003-322217 A (Claim 1, Example)

  An object of the present invention is to provide a transmission belt that can achieve both slidability and side pressure resistance (rigidity or bending strength).

  Another object of the present invention is to provide a transmission belt capable of improving durability and wear resistance and further improving sound resistance.

  Still another object of the present invention is to provide a transmission belt that can improve adhesion to the insert material even if the block is a transmission belt having an insert material.

  Another object of the present invention is to provide a transmission belt that is excellent in productivity (or handleability) while improving slidability, side pressure resistance and wear resistance.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventor has formed a friction transmission surface of a block constituting a transmission belt with a resin composition containing a resin component, carbon fiber, and graphenes, thereby achieving slidability. The present invention has been completed by discovering that both the pressure resistance and the lateral pressure resistance can be achieved.

  That is, the transmission belt according to the present invention includes a tension belt and a plurality of blocks arranged at substantially equal intervals in the length direction of the tension belt and integrated with the tension belt by fitting. And the friction transmission surface of the said block is formed with the resin composition containing a resin component, carbon fiber, and graphene. The ratio of the graphenes is about 0.5 to 10% by mass with respect to the entire resin composition. The ratio of the graphenes is about 1 to 30 parts by mass with respect to 100 parts by mass of the carbon fiber. The average particle size of the graphenes is about 0.1 to 3 μm. The resin component may be a phenol resin. The phenol resin may contain at least a novolac phenol resin (or a novolac type phenol resin). The phenol resin may include a novolac phenol resin and a phenol aralkyl resin, and the novolac phenol resin may be included in a proportion exceeding 50% by mass with respect to the total amount of the novolac phenol resin and the phenol aralkyl resin. The carbon fiber may have an average fiber length of 100 μm or more and an average fiber diameter of 5 to 15 μm. The carbon fiber may include polyacrylonitrile-based carbon fiber and pitch-based carbon fiber. The pitch-based carbon fiber may be an anisotropic pitch-based carbon fiber. The block may include an insert material, and the resin composition may form a resin coating layer on the friction transmission surface.

  In the present invention, since the friction transmission surface of the block constituting the transmission belt is formed of a resin composition containing a resin component, carbon fiber, and graphenes, both slidability and side pressure resistance (rigidity) can be achieved. . In addition, the durability and wear resistance of the transmission belt can be improved, and the sound resistance can also be improved. Furthermore, since the ratio of graphenes can be suppressed to a small amount, even if the block is a transmission belt having an insert material, adhesion with the insert material can be improved. In addition, it has high productivity (or handleability) while improving slidability, side pressure resistance and wear resistance.

FIG. 1 is a schematic perspective view showing an example of a transmission belt of the present invention. 2 is a cross-sectional view of the transmission belt in FIG. 1 in the width direction. FIG. 3 is a schematic view of blocks constituting the transmission belt of FIG. FIG. 4 is a side view of the transmission belt of FIG. FIG. 5 is a schematic view for explaining the speed change mechanism of the belt type continuously variable transmission. FIG. 6 is a schematic cross-sectional view of blocks constituting the transmission belt of FIG. FIG. 7 is a schematic diagram for explaining a method of measuring the friction coefficient and the wear amount of the block in the embodiment.

[Structure of transmission belt]
The power transmission belt (friction power transmission belt) of the present invention includes a tension band and a plurality of blocks arranged at substantially equal intervals in the length direction of the tension band and integrated with the tension band by fitting. A friction transmission belt called a conventional high-load transmission V-belt (or resin block belt) widely used in high-load transmission applications such as high-displacement automobiles and scooters. Have the same structure.

  FIG. 1 is a schematic perspective view showing an example of the transmission belt of the present invention, and FIG. 2 is a cross-sectional view in the width direction of the transmission belt of FIG. FIG. 3 is a schematic view of the blocks constituting the transmission belt of FIG. 1, and more specifically, a plan view (a), a front view (b), a bottom view (c), and a side view (d) of each block. . FIG. 4 is a side view of the transmission belt of FIG.

  As shown in FIGS. 1 and 2, the transmission belt 1 includes two parallel endless tension bands 2 and a direction in which the plate surface is perpendicular to the longitudinal direction of the tension bands 2 (longitudinal direction of the belt). It is composed of a plurality of plate-like blocks 10 arranged at equal pitches and integrated with the tension band 2. As shown in FIG. 3, each block 10 has the same shape and has a structure in which two upper beam portions 11 and lower beam portions 12 arranged in the vertical direction are connected by a center pillar portion 13 at the center in the belt width direction. The shape of the plate surface is substantially H-shaped. That is, the block 10 is formed with a pair of fitting grooves 14 surrounded by the upper and lower beam portions 11 and 12 and the center pillar portion 13. Each tension band 2 is press-fitted into each fitting groove 14 of each block 10 from both sides in the belt width direction, and each block 10 is integrated with the two tension bands 2.

  The length in the belt width direction of the upper beam portion 11 and the lower beam portion 12 of the block 10 is the longest at the upper end portion and shortens toward the lower end portion, and the shape in the belt width direction forms a substantially inverted trapezoidal shape. ing. When the transmission belt 1 is wound around each pulley (each pulley 31 and 32 in FIG. 5 described later), the upper beam portion 11 of each block 10 is positioned on the pulley outer diameter side with respect to the tension band 2, and the lower side The beam portion 12 is located closer to the pulley inner diameter side than the tension band 2. That is, the side surface extending in the longitudinal direction of the belt is in contact with the pulley, and the tension band exposed on the side surface of the belt and the side surface portion of the block sandwiching the top and bottom of the exposed portion of the tension band form a friction transmission surface.

  As shown in FIGS. 1 and 4, concave grooves 21a and 21b extending in the belt width direction are formed on the outer peripheral surface and inner peripheral surface of each tension band 2 at a predetermined pitch in the belt longitudinal direction. Further, on the opposing surface in the vertical direction of the fitting groove 14 in each block 10, ridges 15a and 15b extending in the belt width direction are formed. In the transmission belt 1, the blocks 10 are fixed at a predetermined pitch along the longitudinal direction of the belt by engaging the grooves 15 a and 15 b of the block 10 with the grooves 21 a and 21 b of the tension band 2. The concave groove 21b on the inner peripheral surface of the tension band 2 is formed with a concave curved surface (semicircular cross section) having a gentle cross section compared to the concave groove 21a on the outer peripheral surface having a substantially square cross section. Therefore, the protrusion 15b of the fitting groove 14 that engages with the groove 21b is formed with a convex curved surface having a gentle cross section as compared with the protrusion 15a that engages with the groove 21a.

  Further, as shown in FIG. 3D, the thickness of each block 10 (length in the belt longitudinal direction) is formed with a constant thickness in the vertical direction in the upper beam portion 11 located on the pulley outer diameter side. The lower beam portion 12 located on the pulley inner diameter side is formed so that the thickness gradually decreases toward the lower side, which is the pulley inner diameter side.

  FIG. 5 is a schematic diagram for explaining a transmission mechanism of a belt-type continuously variable transmission that employs the transmission belt 1. As shown in FIG. 5, the belt-type continuously variable transmission 30 has a structure in which an endless transmission belt 1 is wound around a drive pulley 31 and a driven pulley 32. In this belt-type continuously variable transmission 30, the transmission belt 1 is rotated between two axes while the side surface of the transmission belt 1 is in contact with the V grooves of the pulleys 31 and 32, and the gear ratio is continuously changed. .

  Specifically, the pulleys 31 and 32 include fixed pulley pieces 31a and 32a fixed in the axial direction and movable pulley pieces 31b and 32b that are movable in the axial direction. Therefore, in this belt type continuously variable transmission 30, when the movable pulley pieces 31b and 32b move in the axial direction, the pulleys 31 and 32 formed by the fixed pulley pieces 31a and 32a and the movable pulley pieces 31b and 32b. The width of the V groove can be changed continuously. The transmission belt 1 is formed with tapered surfaces whose both end surfaces in the belt width direction are inclined with the V-groove facing surfaces of the pulleys 31 and 32, and according to the changed width of the V-groove, Fit into the position. For example, when the state shown in FIG. 5A is changed to a state where the width of the V groove of the driving pulley 31 is narrowed and the width of the V groove of the driven pulley 32 is widened as shown in FIG. The belt 1 moves in the V groove toward the outer diameter side on the drive pulley 31 side, and moves in the V groove toward the inner diameter side on the driven pulley 32 side. As a result, the wrapping radii around the pulleys 31 and 32 change continuously, and the gear ratio can be changed steplessly.

  The transmission belt of the present invention is not limited to the belt shown in FIGS. 1 to 5, and may be a transmission belt in which a plurality of blocks are fixed to a tension band in a state where a tension band extending endlessly in the belt longitudinal direction can be bent. What is necessary is just to be a transmission belt in which a plurality of blocks are connected in a caterpillar shape with respect to the tension band, and a conventional high load transmission V-belt (resin block belt) can be used.

[block]
The block 10 only needs to be formed of a resin composition containing at least a friction transmission surface (contact surface with a pulley) including a resin component, carbon fiber, and graphenes, and the block 10 is formed of only this resin composition. Alternatively, a block in which at least the friction transmission surface of the insert material is coated with the resin composition may be used.

  FIG. 6 is a schematic cross-sectional view of the block 10, and more specifically, a cross-sectional view (a) in the belt width direction and a cross-sectional view (b) in the belt longitudinal direction at the center in the belt width direction. In this example, the block 10 includes an insert member 40, and the insert member 40 has a structure in which an upper beam portion 41 and a lower beam portion 42 are connected by a center pillar portion 43 at a central portion in the belt width direction. The shape of the facing surfaces 45a and 45b of the upper beam portion 41 and the lower beam portion 42 is not particularly limited, and is usually not formed with a ridge because it can be easily prepared. In many cases, the cross-section of the beam portion is square. The entire surface of the insert 40 is covered with a resin coating layer 50 formed of the resin composition via an adhesive layer 60.

  When the block includes an insert material, the resin coating layer may be formed at least on the friction transmission surface, but is preferably formed on the contact surface with the friction transmission surface and the tension band. That is, it is preferably formed at least on the contact surface with the friction transmission surface and the tension band, and the insert material may be exposed in other portions. However, from the viewpoint of productivity and the like, as shown in FIG. It is particularly preferable to form the entire surface of the material.

  As the block, a block including an insert material is preferable from the viewpoint that side pressure resistance can be improved.

  The block is not limited to the block shown in FIG. 6 as long as the tension band can be bent and integrated with the tension band, and a conventional block can be used.

(Resin composition)
The resin composition for forming the resin coating layer includes a resin component (matrix resin), carbon fibers, and graphenes.

(A) Resin component The resin component includes a thermosetting resin, a thermoplastic resin, a rubber component, and the like. The resin component may be a mixture of these components. Of these, thermosetting resins and thermoplastic resins are widely used as the resin component.

  Examples of the thermosetting resin include thermosetting acrylic resins, phenol resins, amino resins, silicone resins, epoxy resins, vinyl ester resins, unsaturated polyester resins, and polyurethane resins. These thermosetting resins can be used alone or in combination of two or more. Of these thermosetting resins, phenol resins and epoxy resins are preferable, and phenol resins (particularly novolak phenol resins and phenol aralkyl resins) are particularly preferable.

  A novolac-based phenol resin (or novolac-type phenol resin) is a polymer containing a phenol component and an aldehyde component. Examples of the phenol component include monovalent phenolic compounds such as phenol, naphthol and bisphenol A; divalent phenolic compounds such as resorcin and xylenol; trivalent phenolic compounds such as pyrogallol and hydroxyhydroquinone; And derivatives of alkyl, carboxyl, halogen, amine and the like. Examples of the aldehyde component include aliphatic aldehydes such as formaldehyde and acetaldehyde; aromatic aldehydes such as benzaldehyde and furfural. The molar ratio of the phenol component and the aldehyde component in the novolak phenol resin is appropriately set in consideration of their valence balance. The novolac phenol resin may be composed of a single species or a plurality of species.

  The phenol aralkyl resin is a polymer containing a phenol component and an aralkyl component. Examples of the phenol component include alkylphenols such as phenol, o-cresol, m-cresol, p-cresol, o-ethylphenol, m-ethylphenol, and p-ethylphenol; naphthols such as 1-naphthol and 2-naphthol A hydroxyaryl compound such as hydroxybiphenyl; a phenol compound having a functional group other than a hydroxyl group such as polyhydric phenol and salicylic acid. Examples of the aralkyl component include p-xylylene, m-xylylene, o-xylylene, biphenyldimethylene, naphthylene dimethylene and the like. The phenol aralkyl resin may be composed of a single species or a plurality of species.

  Examples of the thermoplastic resin include polyamide, polyamideimide, polyphenylene sulfide, polyether ether ketone, and polyether sulfone. These thermoplastic resins can be used alone or in combination of two or more. Of these thermoplastic resins, polyamide is preferable from the viewpoint of moldability, and aliphatic polyamide such as polyamide 46 and aromatic polyamide such as polyamide 9T are particularly preferable.

  Among these, in view of heat resistance and durability, thermosetting resins are preferable, and phenol resins such as novolac phenol resins (or novolac-type phenol resins) and phenol aralkyl resins are particularly preferable. The ratio of the phenol resin is, for example, 50% by mass or more (for example, 60 to 100% by mass), preferably 70% by mass or more (for example, 80 to 99% by mass), and more preferably 90% by mass with respect to the entire resin component. % Or more (for example, 95 to 99% by mass), and particularly substantially 100% by mass.

  Among the phenol resins, the resin component preferably contains at least a novolac phenol resin from the viewpoint of easy preparation of a resin composition and excellent productivity (handleability or moldability). The ratio of the novolac phenol resin may be selected, for example, from a range exceeding 50% by mass with respect to the entire phenol resin, for example, 50.1% by mass or more (for example, 50.5 to 100% by mass), Preferably, it may be 60% by mass or more (for example, 70 to 99% by mass), more preferably 80% by mass or more (for example, 90 to 99% by mass), or substantially 100% by mass.

  Moreover, the resin component may contain the phenol aralkyl resin from the point which can improve side pressure resistance and abrasion resistance further. Phenol aralkyl resins are not only difficult to knead with other components such as carbon fibers, but also require high temperatures for curing (or annealing), which may reduce the productivity (handleability or moldability) of the transmission belt. Therefore, it is often used in combination with a novolac phenolic resin. When the resin component contains both a novolac phenol resin and a phenol aralkyl resin, the mass ratio of the novolac phenol resin is larger than that of the phenol aralkyl resin, that is, exceeds 50% by mass with respect to the total amount of the two resins. It is often selected from the range, for example, 50.5% by mass or more (for example, 55-99.9% by mass), preferably 60% by mass or more (for example, 70-99% by mass), and more preferably 80% by mass. % Or more (for example, 90 to 95% by mass). If the proportion of the novolac phenol resin is too small, the productivity may be lowered. In the present invention, since the resin composition contains graphene, the characteristics such as side pressure resistance, wear resistance, and slidability of the transmission belt can be sufficiently improved. Therefore, even if the phenol aralkyl resin is not included. Good.

(B) Carbon fiber Examples of the carbon fiber include polyacrylonitrile (PAN) -based carbon fiber, pitch-based carbon fiber [for example, isotropic pitch-based carbon fiber, anisotropic pitch-based carbon fiber (or mesophase pitch-based carbon fiber). Etc.], phenol resin-based carbon fibers, regenerated cellulose-based carbon fibers (for example, rayon-based carbon fibers, polynosic-based carbon fibers), cellulose-based carbon fibers, polyvinyl alcohol-based carbon fibers, and the like. These carbon fibers can be used alone or in combination of two or more. Of these carbon fibers, PAN-based carbon fibers and pitch-based carbon fibers are preferable. Among these, PAN-based carbon fibers are preferably included because the strength (or lateral pressure resistance) and wear resistance can be further improved, and the pitch can be further improved because the slidability (reduction of friction coefficient) can be further improved. It is preferable to contain a carbon fiber. Therefore, a combination of PAN-based carbon fibers and pitch-based carbon fibers is particularly preferable from the viewpoint of satisfying a good balance of side pressure resistance, wear resistance, and slidability to improve durability.

  Further, the pitch-based carbon fiber may be an isotropic pitch-based carbon fiber. However, the anisotropic pitch-based carbon has a relatively high mechanical property (strength) with little disturbance of the graphite crystal structure. It is preferably a fiber.

  When combining the PAN-based carbon fiber and the pitch-based carbon fiber, the mass ratio of the two is the former / the latter = 3/1 to 1/3, preferably 2/1 to 1/2, more preferably 1.5 / 1. About 1 / 1.5 (particularly 1.3 / 1 to 1/1).

  The average fiber diameter of the carbon fiber is, for example, about 1 to 30 μm, preferably 3 to 20 μm, and more preferably about 5 to 15 μm. If the fiber diameter is too small, it may be difficult to disperse uniformly, and if it is too large, the reinforcing effect may be reduced.

  The average fiber length of the carbon fiber may be 100 μm or more, for example, 150 μm or more (for example, 150 μm to 50 mm), preferably 300 μm or more (for example, 300 μm to 30 mm), more preferably 500 μm or more (for example, 500 μm to 20 mm), particularly 1 mm. It may be more (for example, 1 to 10 mm). If the fiber length is too short, the reinforcing effect may be reduced.

  In the present specification and claims, the average fiber diameter and average fiber length of the carbon fibers are obtained by dissolving the resin coating layer containing carbon fibers in nitric acid, and then filtering, washing and drying to take out the carbon fibers. Using a digital microscope having an image analysis function, it can be obtained by a method of averaging the fiber diameter and fiber length of 20 randomly extracted carbon fibers.

  The tensile strength (JIS R7606: 2000) of the carbon fiber may be 2300 MPa or more (for example, about 2300 to 4000 MPa), and the tensile modulus (JIS R7606: 2000) is 230 GPa or more (for example, about 230 to 700 GPa). Also good.

  The ratio of the carbon fiber is, for example, about 5 to 40% by mass, preferably 10 to 35% by mass, and more preferably about 15 to 30% by mass (particularly 20 to 25% by mass) with respect to the entire resin composition. If the proportion of carbon fiber is too small, the reinforcing effect may be reduced, and if too large, injection molding of the block may be difficult.

(C) Graphenes Graphenes act as a solid lubricant (friction coefficient reducing material) and can reduce the friction coefficient in a small amount compared to conventional solid lubricants, so there is a trade-off relationship in the conventional technology, It is possible to achieve both the slidability and side pressure resistance of the transmission belt, which was difficult to achieve. Furthermore, surprisingly, unlike conventional solid lubricants, graphenes may be improved without adversely affecting the side pressure resistance and wear resistance even if they are contained in a large amount. Further, it is possible to achieve both higher side pressure resistance and further wear resistance at a higher level.

  The graphenes include a graphene sheet that is a single sheet usually referred to as “graphene” and a graphene film (multilayer graphene) that is a laminate of the graphene sheets.

  The graphene sheet is a material constituting graphite, and is a sheet of sp2 bonded carbon atoms (single layer sheet) having a thickness of 1 atom. The structure has a hexagonal lattice structure (honeycomb structure) like a honeycomb formed from carbon atoms and their bonds.

  The graphene film is obtained by exfoliating graphite, is a thin laminate compared with graphite, and has a crystal structure. The number of stacked graphene films is, for example, about 2 to 20, and preferably about 3 to 10.

  The aspect ratio (average diameter / average thickness of the plate surface) of the graphene film may be 20 or more, for example, about 20 to 100,000, preferably about 50 to 30,000, and more preferably about 100 to 10,000. The average thickness of the graphene film may be, for example, about 1 to 10 nm, preferably about 1.5 to 5 nm.

  The graphenes may contain graphene oxide or may be formed of only graphene oxide.

  The shape of the graphenes (secondary aggregates) is not particularly limited, and examples thereof include a sheet shape, a granular shape (powdered shape or an indefinite shape), a combined shape of a sheet shape and a granular shape, and the like. Of these shapes, granular is preferable because it is easy to handle and easily disperses uniformly in the resin component.

  When the graphenes are granular, the average particle diameter of the graphenes may be 50 μm or less, for example, 0.01 to 50 μm, preferably 0.03 to 10 μm, more preferably 0.05 to 5 μm (particularly 0. 1 to 3 μm). If the average particle size is too large, aggregates are likely to be formed in the resin component, and it may be difficult to disperse uniformly.

  In the present specification and claims, the average particle diameter of graphenes was observed with a scanning electron microscope (“JSM-5900LV” manufactured by JEOL Ltd.) at a magnification of 5000 times, and was randomly selected. The particle diameter of each particle can be measured and averaged.

  Graphenes can be produced by a conventional method, and may be produced, for example, by a method described in Japanese Patent No. 5688669, Japanese Patent No. 5697067, Japanese Patent Application Laid-Open No. 2015-501873, WO2013 / 146213.

  The ratio of the graphenes can be selected from the range of about 0.1 to 10% by mass with respect to the entire resin composition, for example, 0.3 to 8% by mass, preferably 0.5 to 5% by mass, and more preferably 0. .6 to 3% by mass (especially 0.8 to 2% by mass) may be used, and 0.5 to 10% by mass, for example, from the viewpoint that side pressure resistance, slidability and wear resistance can be further improved. Preferably, it may be about 1 to 8% by mass, more preferably about 2 to 7% by mass (particularly 4 to 6% by mass). Above all, the ratio of graphene is the whole resin composition because it has excellent balance of various characteristics such as side pressure resistance, sliding property, abrasion resistance, sound resistance, adhesion to insert material and productivity. For example, it is preferably about 0.7 to 2% by mass (particularly 0.8 to 1.5% by mass). The proportion of graphene may be, for example, 1 to 10 parts by mass, preferably 2 to 8 parts by mass, and more preferably about 3 to 5 parts by mass with respect to 100 parts by mass of carbon fiber. From the point which can improve a mobility and abrasion resistance more, for example, about 1-30 mass parts, Preferably it is 4-26 mass parts, More preferably, it may be about 8-24 mass parts (especially 15-22 mass parts). . Especially, from the point which is excellent in the balance of various characteristics, such as side pressure resistance, slidability, abrasion resistance, sound-proofing property, adhesiveness with insert material, and productivity, it is 2-9 mass parts (especially 3- It is preferably about 5 parts by mass). If the proportion of graphene is too small, the effect of reducing the friction coefficient may be reduced. If it is too large, blending with the resin component may be difficult, and adhesion to a metal reinforcing material (insert material) will occur. There is a risk that the performance will be reduced.

(D) Other additives The resin composition may further include a conventional solid lubricant, a friction modifier, and a fiber reinforcing material other than the carbon fiber.

  Examples of the solid lubricant include graphite, fluororesin (such as polytetrafluoroethylene), molybdenum disulfide, and ultrahigh molecular weight polyethylene. These solid lubricants can be used alone or in combination of two or more. Examples of the friction modifier include calcium carbonate, calcium phosphate, potassium titanate, aluminum borate, alumina, iron powder, zinc oxide, mica, talc (hydrous magnesium silicate), pyrophyllite (caurolite clay) and the like. It is done. These friction modifiers can be used alone or in combination of two or more. The total ratio of the solid lubricant and the friction modifier may be 50% by mass or less based on the total amount of the graphene, for example, 0.5 to 49.5% by mass (particularly 1 to 30% by mass). )

  Examples of the fiber reinforcing material include aramid fiber, nylon fiber, polyester fiber, and the like. These fiber reinforcing materials can be used alone or in combination of two or more. The average fiber length of the fiber reinforcing material is, for example, about 0.5 to 6 mm (for example, 1 to 5 mm), and the average fiber diameter is about 2 to 100 μm (for example, 5 to 50 μm). The ratio of the fiber reinforcing material may be 50% by mass or less with respect to the entire resin composition, such as 1 to 20% by mass (particularly 2 to 10% by mass). )

  The resin composition further contains conventional additives such as processing agents or processing aids (stearic acid, metal stearates, waxes, paraffins, etc.), metal oxides, curing agents (amines, etc.), alkalis (hydroxylation). Calcium etc.) may be included. The ratio of these additives is about 1 to 30% by mass with respect to the entire resin composition.

(Insert material)
In the present invention, the side pressure resistance of the transmission belt 1 can be improved by combining the resin composition and the insert material (reinforcing material).

  The insert material may be substantially the same shape (slightly smaller similar shape) as the entire shape of the block. Normally, the insert material is similar to the block as shown in FIG. The beam part may be formed in a substantially H shape by connecting the center part in the belt width direction by a center pillar part.

  The insert material only needs to be formed of a hard material having a hardness higher than that of the resin coating layer formed of the resin composition, but usually a simple metal such as iron, an alloy such as an aluminum alloy, ceramics, ceramics and metal (For example, aluminum) or a fiber reinforced resin such as a carbon fiber reinforced resin. These hard materials can be used alone or in combination of two or more. Among these hard materials, a duralumin material that is an aluminum alloy is preferable from the viewpoint of excellent heat resistance and high strength.

  Examples of the duralumin material include an aging treatment material of a metal material made of an aluminum alloy such as alloy numbers 2017, 2014, 2024, and A7075 in JIS standards. Of these duralumin materials, JIS H A2024P T361 duralumin material is particularly preferred because of its excellent heat resistance and strength. In this duralumin material, “A2024P” is an aluminum alloy rolled material, “2024” is the metal composition, “T361” is the cross-sectional area reduction rate of “T3” is approximately 6%. Respectively. Furthermore, “T3” means that cold working was performed after the solution treatment and further natural aging was performed. The rolled material having this alloy number has the property that it can sufficiently withstand high temperatures and is not easily softened.

  For example, the length of the upper beam portion in the belt thickness direction is 3.5 to 7 mm, the length of the center pillar portion in the belt thickness direction is 3.5 to 7 mm, and the length of the lower beam portion in the belt thickness direction is, for example, Is about 3.5 to 7 mm.

(Adhesive layer)
The adhesive layer is interposed between the resin coating layer and the insert material in order to improve the adhesion between the resin coating layer and the insert material, but the resin is directly applied to the surface of the insert material without interposing the adhesive layer. A coating layer may be formed.

  Examples of the adhesive layer may include a coupling agent such as a silane coupling agent and a titanium coupling agent, and a silane having a functional group such as an epoxy group-containing silane coupling agent or an amino group-containing silane coupling agent. A coupling agent is preferred.

  The average thickness of the adhesive layer is, for example, about 0.5 to 5 μm, preferably about 0.8 to 3 μm.

(Block shape)
The shape of the block is not particularly limited as long as it can be fitted and integrated with a tension band (center belt). However, the block has a substantially H-shaped block because the two tension bands can be stably fixed. Is preferred. In the substantially H-shaped block, the shape of the fitting groove for accommodating and fixing the tension band is not particularly limited as long as the tension band can be fixed by fitting. For example, on the opposing surface in the vertical direction of the fitting groove Although the shape which has the protruding item | line or the ditch | groove extended in a belt width direction is mentioned, Usually, it is a shape which has a protruding item | line. Further, the shape of the ridge is not particularly limited as long as it can be integrated with the tension band.

  The size of the block can be appropriately selected according to the type and size of the transmission belt, and is not particularly limited. However, the length in the belt thickness direction is about 10 to 17 mm, the length in the belt width direction is about 20 to 30 mm, and the belt longitudinal direction. The length of is about 2 to 5 mm. The belt angle (side surface inclination angle) is, for example, about 24 to 30 °.

  The pitch of the blocks in the transmission belt integrated with the tension band can be appropriately selected according to the type and size of the belt, and is not particularly limited, but is, for example, about 1 to 6 mm, preferably about 2 to 4 mm. Adjacent blocks need only be separated and may be arranged without any gaps, but are usually arranged with an interval of about 0.01 to 0.1 mm, preferably about 0.02 to 0.08 mm. Yes.

[Tension band]
As shown in FIGS. 1 and 2, the tension band 2 includes a rubber layer 5 in which cores 4 arranged at predetermined intervals in the belt width direction are embedded as a core, and a reinforcing cloth that covers the upper and lower surfaces of the rubber layer 5. 6. Further, as shown in FIGS. 1 and 2, the upper surface (outer peripheral surface) of the tension band 2 has a groove 21 a that can be engaged with the ridge 15 a of the block 10 in the belt (tension band) width direction. In the lower surface (inner peripheral surface) of the tension band 2, a groove 21 b that can be engaged with the ridge 15 b of the block 10 extends in the belt (tension band) width direction.

  The tension band is not limited to the tension band having the shape shown in FIGS. 1-2 and 4 as long as it can be integrated with the block by fitting, and a conventional tension band (center belt) can be used according to the shape of the block. ) Can be used. Furthermore, the number of tension bands is not limited to two, and may be one or three or more. However, the number of tension bands is usually two in terms of belt durability and running stability.

(Core)
The core 4 as the core body is disposed so as to extend in the longitudinal direction of the belt, and generally extends in parallel with the longitudinal direction of the belt and is disposed in parallel at a predetermined pitch in the belt width direction. As the core wire, for example, a twisted cord made of polyester fiber, polyamide fiber, aramid fiber, glass fiber, carbon fiber or the like, a steel wire, or the like is used. In the power transmission belt of the present invention, instead of the core wire, a woven fabric or a knitted fabric made of fibers forming the cord twist cord, or a metal thin plate may be embedded as a core.

(Rubber layer)
Examples of the rubber layer 5 include chloroprene rubber, natural rubber, acrylonitrile butadiene rubber (nitrile rubber), styrene-butadiene rubber, and hydrogenated nitrile rubber (including a mixed polymer of hydrogenated nitrile rubber and unsaturated carboxylic acid metal salt). , Single rubbers such as ethylene-α-olefin elastomers [ethylene-α-olefin rubbers such as ethylene-propylene copolymer (EPM), ethylene-propylene-diene terpolymer (EPDM)], or these rubbers May be formed of rubber appropriately blended with polyurethane or polyurethane rubber. The rubber layer may contain a conventional additive.

(Reinforcing cloth)
The reinforcing cloth 6 is disposed in order to prevent the rubber layer 5 from being worn by friction with the block 10 during belt running, and is usually formed of a woven cloth such as a plain weave, a twill weave or a satin weave. As the fiber material constituting the woven fabric, for example, aramid fiber, polyamide fiber, polyester fiber and the like are used. Of these fiber materials, aramid fibers having excellent wear resistance are preferable from the viewpoint of preventing abrasion due to friction between the block and the tension band, and are excellent in stretchability and excellent in conformity to the shape of the fitting groove of the block. From the viewpoint, polyamide fibers such as aliphatic polyamide fibers are preferable.

[Production method of transmission belt]
(Block manufacturing process)
The block can be produced by a conventional method. For example, the block can be produced by preparing the resin composition and then molding the obtained resin composition.

  As a method for preparing the resin composition, for example, a resin component, carbon fiber, and graphene (and other additives as necessary) are charged into a resin kneader such as a biaxial kneader, kneaded, and recovered. Examples thereof include a method of pulverizing an object to form powder or granulate.

  As a method for molding a resin composition, for example, the resin for forming a resin coating layer in a cavity after an insert material (metal reinforcing material) is placed in a mold cavity of a block molding machine and clamped Examples thereof include a method of forming a block by supplying a composition. In addition, when not using insert material for a block, the method of supplying a resin composition, etc., without arrange | positioning insert material in the cavity of a metal mold | die etc. are mentioned.

  When the resin component includes a thermosetting resin (such as a phenol resin), it may be cured by heat treatment (or annealing treatment). The heat treatment conditions may be appropriately selected according to the type of resin or curing agent, and the heating temperature is, for example, about 100 to 250 ° C., preferably 150 to 200 ° C., more preferably about 170 to 190 ° C. Good. The heating time may be, for example, 0.5 to 24 hours, preferably 0.5 to 12 hours, and more preferably about 3 to 7 hours. If the heating temperature is too high, the productivity may decrease and the physical properties of the insert material may decrease. Note that the heat treatment may be performed by increasing the heating temperature stepwise (eg, divided into about three steps), but is preferably performed in one step from the viewpoint of productivity.

(Manufacturing process of tension band)
The tension band can also be produced by a conventional method. For example, after preparing a sheet-like uncrosslinked rubber composition, a core wire precursor, and a reinforcing cloth precursor, they can be molded using these materials.

  As a preparation method of the sheet-like uncrosslinked rubber composition, for example, after kneading the raw rubber into a rubber kneading machine such as a Banbury mixer, the compounding agent is put into the kneaded raw rubber and kneaded, and further kneaded. Examples thereof include a method of processing the raised uncrosslinked rubber composition into a sheet shape with a calender roll.

  As a method for preparing the core wire precursor, for example, a process of heating a yarn or braid after being immersed in a resorcin-formalin-latex processing solution (RFL processing solution) and / or a processing of drying after being immersed in a rubber paste And the like. Furthermore, you may perform the process dried after being immersed in the process liquid containing an epoxy compound or an isocyanate compound with respect to a twisted thread or a braid before these processes.

  As a method for preparing the reinforcing cloth precursor, for example, a woven cloth, a knitted cloth or a non-woven cloth is heated after being dipped in an RFL treatment solution and / or dried after being dipped in rubber paste or coated with rubber paste. And the like. Furthermore, you may perform the process dried after immersing in the process liquid containing an epoxy compound or an isocyanate compound with respect to a woven fabric, a knitted fabric, or a nonwoven fabric before these processes.

  As a method for forming a tension band using these precursors, for example, the following method may be used. That is, first, a lower reinforcing cloth precursor formed in a cylindrical shape with a cylindrical mold provided with convex grooves extending in the axial direction of the concave groove shape on the inner peripheral surface of the tension band in the circumferential direction. A predetermined layer of an uncrosslinked rubber composition which is coated and processed into a sheet shape is provided thereon.

  Next, a cylindrical mold is placed in the heating and pressurizing apparatus, and the inside of the apparatus is set to a predetermined temperature and pressure so that the crosslinking of the uncrosslinked rubber composition proceeds about half, and the state is maintained for a predetermined time. At this time, the crosslinking of the uncrosslinked rubber composition proceeds about half and the shape of the lower half of the rubber layer is formed, and the uncrosslinked rubber composition flows and the ridges provided on the cylindrical mold are lowered. The side reinforcing cloth is pressed to form a concave groove.

  Subsequently, the cylindrical mold is taken out from the heating and pressurizing apparatus, the core wire precursor is spirally wound at an equal pitch from the semi-crosslinked rubber composition, and the uncrosslinked rubber is processed into a sheet shape again thereon. A predetermined layer of the composition is provided, and an upper reinforcing cloth precursor formed in a cylindrical shape is placed thereon.

  Next, an outer mold in which convex grooves extending in the axial direction of the groove-shaped mold on the outer peripheral surface of the tension band are provided at an equal pitch in the circumferential direction is set.

  Then, a cylindrical mold in which each precursor is set is placed in the heating and pressing apparatus, the interior of the apparatus is set to a predetermined temperature and pressure, and the state is maintained for a predetermined time. At this time, the crosslinking of the semi-crosslinked and uncrosslinked rubber composition proceeds to form a rubber layer. In addition, the adhesive on the surface of the core wire and the rubber layer are interdiffused, so that the core wire is integrally bonded to the rubber layer, and the adhesive and the rubber layer attached to the upper and lower reinforcing fabrics are interdiffused. By doing so, the upper and lower reinforcing fabrics are integrally bonded to the rubber layer. As described above, a cylindrical slab is molded on the surface of the cylindrical mold.

  Finally, the cylindrical mold is taken out from the heating and pressurizing device, the cylindrical slab formed on the peripheral surface is removed from the mold, this is cut into a band with a predetermined width, and a tension band is formed by chamfering or the like. Get.

(Transmission belt manufacturing process)
The protrusion of the fitting groove of the block is made to correspond to the concave groove of the tension band, the tension band is inserted into one fitting groove of the obtained block, and the block is fitted to the tension band. This operation is performed for the entire circumference of the tension band. In the same manner, a transmission belt is obtained by inserting a tension band into the other fitting groove of the block.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

[Preparation of resin composition]
The components shown in Table 1 were charged into a biaxial resin kneader and kneaded, and the recovered kneaded material was pulverized into powder or granules to obtain resin compositions 1 to 14.

  In addition, the detail of the raw material in Table 1 is shown below.

Novolac phenol resin: “PSK-2320” manufactured by Gunei Chemical Industry Co., Ltd.
Phenol aralkyl resin: “XL-325M” manufactured by Mitsui Chemicals, Inc.
Graphene: “GNH-X1” manufactured by Graphene Platform Co., Ltd.
Graphite: “AT-NO.20” manufactured by Oriental Sangyo Co., Ltd.
Carbon nanotube: “VGCF (registered trademark) -H” manufactured by Showa Denko KK
PAN-based carbon fiber: “HT C217” manufactured by Toho Tenax Co., Ltd., average fiber length 6 mm, average fiber diameter 7 μm, tensile modulus 240 GPa
Pitch-based carbon fiber: “K6331T” manufactured by Mitsubishi Chemical Corporation, average fiber length 6 mm, average fiber diameter 11 μm, tensile elastic modulus 640 GPa, anisotropic type aramid short fiber: “Technora (registered trademark)” manufactured by Teijin Limited The average fiber length is 1 mm.

[Strength evaluation of cured product of resin composition]
Table 2 shows the results of molding the test pieces of bending strength and Charpy impact strength using the obtained resin compositions 1 to 14 and evaluating the strength of the cured product of the resin composition. Curing (or annealing) of the resin composition in molding of the test piece was performed by heat-treating the resin compositions 1 to 5 and 7 to 14 at 180 ° C. for 5 hours. Moreover, in the resin composition 6 containing a phenol aralkyl resin, it performed by the three-step heat processing of 180 degreeC for 5 hours, 220 degreeC for 2 hours, and 240 degreeC for 2 hours. In addition, the measuring method of bending strength and Charpy impact strength is as follows.

(Bending strength)
The bending strength was measured according to JIS K 7171 (2008) standard.

(Charpy impact strength)
Charpy impact strength was measured in accordance with JIS K 7111 (2012) standard.

  As is clear from the results in Table 2, the resin compositions 1, 7, 9, 11 and 13 have a ratio of solid lubricants (graphene, graphite, molybdenum disulfide, fluororesin, carbon nanotubes) and the total amount of the resin composition. Therefore, the bending strength and the Charpy impact strength were both high, and the strength of the resin composition was high.

  On the other hand, since the resin composition 8, 10, 12 and 14 had a solid lubricant ratio of 10% by mass with respect to the total amount of the resin composition, the flexural strength and Charpy impact strength were resin compositions 1 to 7, 9 , 11 and 13, the strength of the resin composition was lowered.

  In the resin compositions 1 to 3, unlike the resin compositions using other solid lubricants such as graphite, it was confirmed that the strength of the resin composition was improved as the proportion of graphene increased.

  Resin composition 4 using only PAN-based carbon fibers as carbon fibers has higher strength than resin composition 1, and resin composition 5 using only pitch-based carbon fibers is stronger than resin composition 1. It was a little low. Moreover, although the resin composition 6 containing a phenol aralkyl resin as a resin component has higher strength than the resin composition 1, it needs to be heat-treated at a high temperature for a long time in order to be sufficiently cured. Was low.

[Block molding]
As a block insert material (reinforcing material), duralumin of A2024P T361 was used, and a block in which the insert material was coated with the resin composition 1 was produced (Example 1). The length of the block in the belt thickness direction was 13 mm, the length of the block in the belt longitudinal direction was 2.95 mm, and the belt angle was 26 °. In addition, hardening (or annealing) of the resin composition 1 in the shaping | molding of a block was performed by heat-processing at 180 degreeC for 5 hours.

  Further, blocks were similarly prepared for the resin compositions 2 to 14, and the block coated with the resin composition 2 was coated with the example 2, the block coated with the resin composition 3 was coated with the resin composition 4 and the example 3. The block coated with the resin composition 5 in Example 4, the block coated with the resin composition 6 in Example 6, the block coated with the resin composition 7 in Comparative Example 1, and the resin composition 8 The block coated with the resin composition 9 is comparative example 2, the block coated with the resin composition 9 is comparative example 3, the block coated with the resin composition 10 is comparative example 4, the block coated with the resin composition 11 is comparative example 5, the resin composition The block coated with the product 12 was set as Comparative Example 6, the block coated with the resin composition 13 was set as Comparative Example 7, and the block coated with the resin composition 14 was set as Comparative Example 8. In Example 6 (resin composition 6 containing a phenol aralkyl resin), the heat treatment was performed in three stages of 180 ° C. for 5 hours, 220 ° C. for 2 hours, and 240 ° C. for 2 hours.

[Measurement of friction coefficient and wear amount of block]
As shown in FIG. 7, the molded blocks 71 of Examples 1 to 6 and Comparative Examples 1 to 8 are set in a pin-on-disk friction and wear tester (“TRI-S-500N” manufactured by Takachiho Seiki Co., Ltd.). Under the test conditions shown in Table 3, the mating material 72 was rotated with the surface pressure applied, and the friction coefficient and the wear amount were measured. For the friction coefficient, the voltage of the test torque was sampled every 10 seconds, and an average value for a test time of 70 hours was calculated. The amount of wear was measured by the amount of decrease in the block width direction before and after the test. Table 4 shows the measurement results.

  As is clear from the results in Table 4, the blocks obtained in Examples 1 to 6 (graphene: 1 to 5% by mass) had a small amount of the solid lubricant based on the total amount of the resin composition. Obtained in Example 2 (graphite: 10% by mass), Comparative Example 4 (molybdenum disulfide: 10% by mass), Comparative Example 6 (fluororesin: 10% by mass) and Comparative Example 8 (carbon nanotube: 10% by mass) A higher effect was obtained than the block (lower coefficient of friction and less wear).

  On the other hand, in Comparative Example 1 (graphite: 1% by mass), Comparative Example 3 (molybdenum disulfide: 1% by mass), Comparative Example 5 (fluororesin: 1% by mass) and Comparative Example 7 (carbon nanotube: 1% by mass) In spite of the small amount of the solid lubricant, the effect as in Example 1 was not obtained.

  Further, in Example 4 using only PAN-based carbon fibers as carbon fibers, the friction coefficient and the amount of wear are slightly larger than in Example 1, whereas in Example 5 using only pitch-based carbon fibers, Compared with Example 1, the friction coefficient and the amount of wear could be effectively reduced. As is clear from the results in Tables 2 and 4, it was found that combining PAN-based carbon fibers and pitch-based carbon fibers is effective in achieving a balance between strength and slidability.

  Example 6 containing a phenol aralkyl resin as a resin component was able to reduce the friction coefficient and the amount of wear compared to Example 1. From the results of Tables 2 and 4, it was found that when the novolac phenol resin and the phenol aralkyl resin were contained in a predetermined ratio, the productivity and the slidability could be further improved, although the productivity was reduced as compared with Example 1. .

[Formation of transmission belt]
A number of blocks obtained in Example 1 were incorporated into a tension band, and a transmission belt having the same configuration as the transmission belt shown in FIGS. The transmission belt has a belt circumferential length of 612 mm on the core pitch line, a belt width of 25 mm on the core pitch line, a length of 13 mm in the belt thickness direction of the block, and a length of 2.95 mm in the belt longitudinal direction of the block. The block pitch was 3 mm. Moreover, the transmission belt was similarly produced about Examples 2-6 and Comparative Examples 1-8.

  The rubber layer in the tension band was formed of a rubber composition composed of a mixture of “hydrogenated nitrile rubber” and “hydrogenated nitrile rubber containing zinc dimethacrylate”. As the core wire, a twisted cord of aramid fiber having a diameter of 0.72 mm subjected to a heating process after being immersed in an RFL aqueous solution and a drying process after being immersed in rubber paste was used. Each of the upper and lower reinforcing cloths is a canvas having a thickness of 0.8 mm which has been subjected to a treatment of heating after being immersed in an RFL aqueous solution in a nylon fiber woven fabric, and a treatment of immersing and coating the rubber paste and then drying the rubber paste. Was used.

[Belt durability test]
In the belt durability running test, the transmission belts of Examples 1 to 6 and Comparative Examples 1 to 8 were wound around the drive pulley and the driven pulley, and the drive pulley was rotated in an atmosphere of 70 ° C. The angle of the V groove of the driving pulley and the driven pulley was 26 °, and the winding diameter of the transmission belt around each pulley was a value shown in Table 5. The load was set to the value shown in Table 5, and the rotation speed was set to 5000 rpm when there was no load. The axial load was such that the transmission belt did not slip with respect to the load, and the values shown in Table 5 were used. The distance between the shafts of both pulleys was not fixed so that the shaft load was constant during the traveling of the transmission belt. The belt tension in the stationary state is about half of the axial load. In the belt durability running test, the belt side temperature during running, noise, and the wear amount of the block after running were measured by the following methods. The running time was capped at 400 hours, and when the belt was broken in less than 400 hours, the form of breakage was confirmed. Table 6 shows the measurement results.

(Belt side temperature during running)
The side temperature of the rotating belt was measured in a non-contact manner using a thermometer (“THI-500” manufactured by Itinen TASCO Corporation).

(Noise while driving)
Using a noise meter ("LA-4440" manufactured by Ono Sokki Co., Ltd.) at a position between the driving pulley and the driven pulley, 150 mm in front of the end surface of the belt, the A characteristic was measured.

(Amount of wear after running)
The block width before and after running was measured at five locations with a micrometer, and the average value of the changes was calculated.

  As is clear from the results in Table 6, the transmission belts of Examples 1 to 6 (graphene: 1 to 5% by mass) did not break even after running for 400 hours. Moreover, compared with the comparative example, noise (a primary component of pitch noise) was small, and the amount of wear was also small.

  On the other hand, the transmission belts of Comparative Examples 1, 3, 5 and 7 have a small amount of solid lubricant (1% by mass), so the friction coefficient cannot be reduced and the belt side surface temperature during running increases. The belt was cut when the rubber in the tension band was thermally deteriorated and cracked in the rubber (rubber cracking). Moreover, noise (a primary component of pitch noise) was large and the amount of wear was large.

  In addition, since the transmission belts of Comparative Examples 2, 4, 6, and 8 have a smaller effect of the solid lubricant than that of Example 1, the influence of wear of the reinforcing fabric in the tension band and the sag of the rubber layer due to long-time running. As a result, the backlash between the block and the tension band increased, and the resin block was damaged (resin chipping) at the contact surface with the pulley due to the interface peeling between the insert material and the resin coating layer. In addition, the effect on noise (primary component of pitch noise) and the amount of wear was low compared to the examples.

  As is clear from Tables 2, 4 and 6, Example 1 (or resin composition 1) using an equivalent amount of graphene compared to Comparative Example 7 (or resin composition 13) using carbon nanotubes However, the side pressure resistance, slidability and wear resistance were high. That is, although it is the same nanocarbon material, it has been unexpectedly found that graphene behaves differently from carbon nanotubes, and that the above characteristics can be improved in a balanced manner even with a small blending amount of about 1% by mass.

  The transmission belt of the present invention is a friction transmission V-belt (transmission belt) used in a transmission (continuously variable transmission) whose gear ratio changes steplessly while the belt is running, such as a high displacement vehicle, a scooter, etc. It can be used as a transmission belt for high load transmission applications.

DESCRIPTION OF SYMBOLS 1 ... Transmission belt 2 ... Tensile belt 10 ... Block 11 ... Upper beam part 12 ... Lower beam part 13 ... Center pillar part 14 ... Fitting groove 15a, 15b ... Projection 40 ... Insert material 50 ... Resin coating layer

Claims (11)

  A transmission belt comprising a tension band and a plurality of blocks arranged at substantially equal intervals in the length direction of the tension band and integrated with the tension band by fitting, the friction transmission of the block A power transmission belt having a surface formed of a resin composition containing a resin component, carbon fiber, and graphenes.   The power transmission belt according to claim 1, wherein a ratio of the graphenes is 0.5 to 10% by mass with respect to the entire resin composition.   The transmission belt according to claim 1 or 2, wherein the proportion of the graphene is 1 to 30 parts by mass with respect to 100 parts by mass of the carbon fiber.   The power transmission belt according to any one of claims 1 to 3, wherein the graphene has an average particle size of 0.1 to 3 µm.   The transmission belt according to any one of claims 1 to 4, wherein the resin component is a phenol resin.   The transmission belt according to claim 5, wherein the phenol resin contains at least a novolac phenol resin.   The phenol resin contains a novolac-based phenol resin and a phenol aralkyl resin, and the novolac-based phenol resin in a proportion exceeding 50% by mass with respect to the total amount of the novolac-based phenol resin and the phenol aralkyl resin. Power transmission belt.   The power transmission belt according to any one of claims 1 to 7, wherein the carbon fibers have an average fiber length of 100 µm or more and an average fiber diameter of 5 to 15 µm.   The transmission belt according to any one of claims 1 to 8, wherein the carbon fibers include polyacrylonitrile-based carbon fibers and pitch-based carbon fibers.   The power transmission belt according to claim 9, wherein the pitch-based carbon fiber is an anisotropic pitch-based carbon fiber.   The transmission belt according to any one of claims 1 to 10, wherein the block includes an insert material, and the resin composition forms a resin coating layer on a friction transmission surface.