Transmission belt

Abstract

To prevent a carbon fiber-based core wire from popping out during belt running.SOLUTION: A transmission belt comprises a rubber layer 11 in which a carbon fiber-based core wire 20 is embedded so as to form a spiral having a pitch in a belt width direction. A core wire protection material 21 is attached to the core wire 20 so as to cover the surface of the core wire 20 and be interposed between carbon fiber-based filaments F that form the core wire 20. An indentation elastic modulus of the core wire protection material 21 is three or more times an indentation elastic modulus of the rubber layer 11.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a power transmission belt. [Background technology]

[0002] 2. Description of the Related Art A power transmission belt having a core wire made of carbon fiber is known. Patent Document 1 discloses a technique for bonding the carbon fiber core wire in such a power transmission belt to a rubber belt body. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6034783 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, a relatively common failure mode in power transmission belts used under high load is pop-out, in which the core wire separates from the belt body and pops out while the belt is running.

[0005] An object of the present invention is to suppress the pop-out of carbon fiber cords when a belt is running. [Means for solving the problem]

[0006] The present invention provides a power transmission belt having a rubber layer in which a carbon fiber core wire is embedded so as to form a spiral having a pitch in the belt width direction, wherein a core wire protection material is attached to the core wire, covering the surface of the core wire and being interposed between the carbon fiber filaments forming the core wire, and the indentation elastic modulus of the core wire protection material is at least three times the indentation elastic modulus of the rubber layer. Effect of the Invention

[0007] According to the present invention, the indentation elastic modulus of the core wire protection material attached to the carbon fiber core wire embedded in the rubber layer is three or more times the indentation elastic modulus of the rubber layer, thereby making it possible to suppress pop-out of the carbon fiber core wire when the belt is running. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view of a piece of a cogged V-belt according to an embodiment. [Diagram 2] 1 is a cross-sectional view taken along the belt width direction of a cogged V-belt according to an embodiment. [Diagram 3] 1 is a cross-sectional view taken along the belt length direction of a cogged V-belt according to an embodiment. [Figure 4] 4 is a cross-sectional view showing a schematic configuration of a portion in which a core wire is embedded in an adhesive rubber layer. FIG. [Diagram 5] FIG. 1 is a diagram showing a pulley layout of a belt running test machine for a high-load durability belt running test. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The embodiments will be described in detail below.

[0010] 1 to 3 show a cogged V-belt (power transmission belt) B according to an embodiment. This cogged V-belt B is an endless friction power transmission belt made of rubber, and is used, for example, as a power transmission member for agricultural machinery. The dimensions of the cogged V-belt B are, for example, a belt length of 500 mm to 1200 mm, a maximum belt width of 16 mm to 30 mm, and a maximum belt thickness of 8.0 mm to 12.0 mm.

[0011] The cogged V-belt B according to the embodiment includes a rubber V-belt body 10, a carbon fiber core 20, an inner reinforcing cloth 30, and an outer reinforcing cloth 40.

[0012] The cross-sectional shape of the V-belt body 10 along the belt width direction is an isosceles trapezoid with the upper base on the inner circumferential side and the lower base on the outer circumferential side. Both side surfaces of the V-belt body 10 constitute power transmission surfaces that come into contact with the pulleys. The angle between both side surfaces of the V-belt body 10 is, for example, 24° to 36°.

[0013] The V-belt body 10 has an adhesive rubber layer 11 provided in the middle part near the outer periphery in the belt thickness direction, a compressed rubber layer 12 provided on the inner periphery side thereof, and an tensile rubber layer 13 provided on the outer periphery side thereof. On the inner periphery of the compressed rubber layer 12, bottom cog forming portions 121 whose edges in the cross section along the belt length direction are shaped like a sine curve are arranged at a constant pitch.

[0014] The adhesive rubber layer 11 is formed of a rubber composition in which an uncrosslinked rubber composition, in which various rubber compounding agents are mixed and kneaded with a rubber component, is heated and pressurized to crosslink the rubber component.

[0015] Examples of the rubber component of the rubber composition forming the adhesive rubber layer 11 include chlorine-containing rubbers such as chloroprene rubber (CR) and chlorosulfonated polyethylene rubber (CSM), hydrogenated acrylonitrile rubber (H-NBR), and ethylene-α-olefin elastomers such as ethylene propylene diene monomer (EPDM). The rubber component of the rubber composition forming the adhesive rubber layer 11 preferably contains one or more of these, and from the viewpoint of suppressing pop-out of the carbon fiber core wire 20 as described below, it is more preferable that it contains a chlorine-containing rubber, even more preferable that it contains CR, and even more preferable that it contains only CR.

[0016] The rubber composition forming the adhesive rubber layer 11 may contain a reinforcing material such as carbon black, a plasticizer, a processing aid, an antiaging agent, etc. Furthermore, a crosslinking agent or a co-crosslinking agent may be blended into the uncrosslinked rubber composition before crosslinking. Examples of the crosslinking agent include sulfur and organic peroxides, but when the rubber component contains CR, examples of the crosslinking agent include metal oxides such as magnesium oxide and zinc oxide.

[0017] Indentation elastic modulus E of adhesive rubber layer 11 IT From the viewpoint of suppressing the pop-out of the core wire 20, the strength is preferably 300 N / mm 2 More than 500N / mm 2 Less than or equal to 350N / mm 2 More than 450N / mm 2 The indentation elastic modulus E of the adhesive rubber layer 11 in this application is as follows. IT is measured based on ISO 14577-1 for the adhesive rubber layer 11 exposed on a cross section along the belt width direction of the cogged V-belt B. IT It can be controlled by the blending of the uncrosslinked rubber composition for forming the adhesive rubber layer 11 and the conditions for crosslinking the uncrosslinked rubber composition.

[0018] The core wire 20 is embedded in the middle of the belt thickness direction of the adhesive rubber layer 11 so as to form a spiral having a pitch in the belt width direction. Therefore, cut ends of the core wire 20 are exposed on both side surfaces of the adhesive rubber layer 11. The outer diameter of the core wire 20 is, for example, 0.6 mm or more and 2.2 mm or less.

[0019] The carbon fiber forming the core wire 20 is preferably a PAN-based carbon fiber from the viewpoint of suppressing pop-out of the core wire 20. From the same viewpoint, the filament diameter of the carbon fiber is preferably 4 μm or more and 9 μm or less, more preferably 6 μm or more and 8 μm or less. The surface of the carbon fiber filament may be subjected to a surface treatment with a sizing agent such as a silane coupling agent or an epoxy resin.

[0020] The total number of carbon fiber filaments forming the core wire 20 is preferably 1,000 (1K) or more and 48,000 (48K) or less, more preferably 9,000 (9K) or more and 18,000 (18K), and even more preferably 12,000 (12K), in terms of suppressing pop-out of the core wire 20.

[0021] The core wire 20 is preferably made of twisted yarn. Examples of twisted yarn constituting the core wire 20 include single twisted yarn, multiple twisted yarn, and Lang twisted yarn. From the viewpoint of suppressing pop-out of the core wire 20, the twisted yarn core wire 20 is preferably a single twisted yarn obtained by twisting a filament bundle of carbon fiber in one direction. From the same viewpoint, the number of twists of the single twisted yarn core wire 20 is preferably 5 times / 10 cm or more and 15 times / 10 cm or less, more preferably 7 times / 10 cm or more and 10 times / 10 cm or less. The single twisted yarn core wire 20 may be made of S twisted yarn, Z twisted yarn, or both of them may be arranged to form a double helix.

[0022] As shown in FIG. 4, the core wire 20 has a core wire protection material 21 attached thereto, which covers the surface of the core wire 20 and is interposed between the carbon fiber filaments F that form the core wire 20.

[0023] The core wire protection material 21 is preferably made of a cured treatment agent that is attached by immersing a bundle of carbon fiber filaments in a liquid treatment agent and then heating the bundle before twisting to form the core wire 20. The core wire 20 is formed into a twisted yarn by twisting the bundle of carbon fiber filaments to which the core wire protection material 21 is attached.

[0024] In this case, the liquid treatment agent preferably has latex as a base agent. Therefore, the core wire protection material 21 is preferably formed of a rubber composition having a latex-derived rubber component as a matrix. The liquid treatment agent may be a so-called RFL aqueous solution, but from the viewpoint of suppressing pop-out of the core wire 20, it is preferable that it is not an RFL aqueous solution. Therefore, the liquid treatment agent and the rubber composition forming the core wire protection material 21 preferably do not contain a resorcinol-formaldehyde condensate.

[0025] Examples of the latex include nitrile rubber latexes such as nitrile rubber (acrylonitrile-butadiene copolymer rubber) latex, hydrogenated nitrile rubber latex, carboxyl-modified nitrile rubber latex, and carboxyl-modified hydrogenated nitrile rubber latex; chlorine-based rubber latexes such as chloroprene rubber latex and chlorosulfonated polyethylene rubber latex; butadiene-styrene copolymer rubber latex; dicarboxylated butadiene-styrene copolymer rubber latex; butadiene-styrene copolymer rubber latexes such as vinylpyridine-butadiene-styrene copolymer rubber latex; butadiene rubber latex, etc. The latex preferably contains one or more of these, and from the viewpoint of suppressing pop-out of the core wire 20, it is more preferable that the latex contains a nitrile rubber latex, and it is even more preferable that the latex contains a carboxyl-modified nitrile rubber latex and / or a carboxyl-modified hydrogenated nitrile rubber latex.

[0026] The liquid treatment agent preferably contains a crosslinking agent that crosslinks polymers of the rubber component contained in the latex, from the viewpoint of suppressing pop-out of the core wire 20. Therefore, in the rubber composition forming the core wire protection material 21, the polymers of the rubber component derived from the latex are preferably crosslinked by the crosslinking agent, and / or the polymers of the rubber component derived from the latex are preferably bonded and crosslinked.

[0027] Examples of the crosslinking agent include maleimide-based crosslinking agents such as bismaleimide, phenylmaleimide, and N,N'-m-phenylenedimaleimide; isocyanate-based crosslinking agents such as aliphatic organic diisocyanates, aromatic organic diisocyanates, polyisocyanates, blocked isocyanates, and blocked polyisocyanates; quinone dioxime-based crosslinking agents such as P-quinone dioxime; methacrylate-based crosslinking agents such as lauryl methacrylate and methyl methacrylate; allyl-based crosslinking agents such as DAF (diallyl fumarate), DAP (diallyl phthalate), TAC (triallyl cyanurate), and TAIC (triallyl isocyanurate); peroxide-based crosslinking agents such as organic peroxides and inorganic peroxides; aromatic nitroso compounds; and sulfur. The crosslinking agent preferably contains one or more of these, and from the viewpoint of suppressing pop-out of the core wire 20, it is more preferable that the crosslinking agent contains a maleimide-based crosslinking agent and / or an isocyanate-based crosslinking agent, and it is even more preferable that the crosslinking agent contains N,N'-m-phenylenedimaleimide and / or polyisocyanate.

[0028] The total amount of the crosslinking agent in the liquid treatment agent is preferably 1 part by mass or more and 40 parts by mass or less, more preferably 2 parts by mass or more and 25 parts by mass or less, based on 100 parts by mass of the rubber component contained in the latex, from the viewpoint of suppressing pop-out of the core wire 20. When the crosslinking agent contains both a maleimide-based crosslinking agent and an isocyanate-based crosslinking agent, particularly when it contains both N,N'-m-phenylenedimaleimide and polyisocyanate, it is preferable that the amount of the maleimide-based crosslinking agent (N,N'-m-phenylenedimaleimide) and the amount of the isocyanate-based crosslinking agent (polyisocyanate) are approximately the same, and specifically, the difference therebetween is preferably within 3 parts by mass based on 100 parts by mass of the rubber component contained in the latex. The amount of each of the maleimide-based crosslinking agent (N,N'-m-phenylenedimaleimide) and the isocyanate-based crosslinking agent (polyisocyanate) is preferably 1 part by mass or more and 20 parts by mass or less, more preferably 1 part by mass or more and 15 parts by mass or less, based on 100 parts by mass of the rubber component contained in the latex.

[0029] From the viewpoint of suppressing pop-out of the core wire 20, the liquid treatment agent and the rubber composition forming the core wire protection material 21 preferably contain a filler.

[0030] Examples of the filler include fine particles of covalent bond compounds such as silica and carbon black, fine particles of poorly soluble salts, fine particles of metal oxides, fine particles of metal hydroxides, fine particles of composite metal oxide salts such as talc, etc. The filler preferably contains one or more of these, and from the viewpoint of suppressing pop-out of the core wire 20, it is more preferable that the filler contains fine particles of covalent bond compounds, and further more preferable that the filler contains silica and / or carbon black.

[0031] The total content of the liquid treatment agent and the filler in the rubber composition forming the core wire protection material 21 is preferably 1 part by mass or more and 10 parts by mass or less, and more preferably 1 part by mass or more and 7 parts by mass or less, per 100 parts by mass of the rubber component contained in the latex, in order to suppress pop-out of the core wire 20.

[0032] The liquid treatment agent and the rubber composition forming the core wire protection material 21 may further contain a plasticizer, an anti-aging agent, a stabilizer, etc. The liquid treatment agent may contain a water-soluble solvent other than water, such as alcohol.

[0033] The amount of core wire protection material 21 attached to the core wire 20 is preferably 2 mass % or more and 50 mass % or less, and more preferably 30 mass % or more and 40 mass % or less, per unit length, with respect to the mass of the core wire 20, from the viewpoint of suppressing pop-out of the core wire 20. The amount of core wire protection material 21 attached to the core wire 20 can be controlled by treatment conditions such as the wettability of the liquid treatment agent used to form the core wire protection material 21 to the carbon fiber, the solids concentration of the liquid treatment agent, and the immersion time of the carbon fiber in the liquid treatment agent.

[0034] Indentation elastic modulus E of the core wire protection material 21 IT From the viewpoint of suppressing pop-out of the core wire 20, it is preferable that the tension is 900 N / mm 2 More than 2000N / mm 2 Less than or equal to 1200N / mm2 More than 1500N / mm 2 The indentation elastic modulus E of the core wire protection material 21 in this application is as follows. IT is measured based on ISO 14577-1 for the core wire protection material 21 exposed on a cross section along the belt width direction of the cogged V-belt B, as in the case of the adhesive rubber layer 11. The indentation elastic modulus of the core wire protection material 21 can be controlled by the blending of the liquid treatment agent for forming the core wire protection material 21, and treatment conditions such as the heating temperature and heating time after immersing the carbon fibers in the liquid treatment agent.

[0035] Indentation elastic modulus E of the core wire protection material 21 IT is the indentation elastic modulus E of the adhesive rubber layer 11 IT The indentation elastic modulus E of the adhesive rubber layer 11 is higher than IT From the viewpoint of suppressing pop-out of the core wire 20, it is preferably 3.1 to 4, more preferably 3.2 to 3.5.

[0036] In this way, according to the cogged V-belt B of the embodiment, the indentation elastic modulus E IT is the indentation elastic modulus E of the adhesive rubber layer 11 IT By making the thickness three or more times larger than the thickness of the adhesive rubber layer 11, it is possible to suppress the pop-out of the carbon fiber core wire 20 when the belt is running. This is presumably because a balance of physical properties against the dynamic action caused by the running of the belt is maintained between the adhesive rubber layer 11 and the core wire protection material 21 attached to the carbon fiber core wire 22.

[0037] The core wire 20 to which the core wire protection material 21 is attached is preferably bonded and integrated with the adhesive rubber layer 11 via a core wire adhesive layer 22 provided so as to cover the surface, as shown in Fig. 4. The core wire protection material 21 may be directly bonded to the adhesive rubber layer 11 without the core wire adhesive layer 22.

[0038] The core wire adhesive layer 22 is preferably made of a cured adhesive coating that is applied by an adhesive treatment in which the core wires 20, after having the core wire protection material 21 attached and twisted, are immersed in a liquid adhesive and dried. The liquid adhesive is preferably a so-called rubber paste in which a rubber composition is dissolved in an organic solvent, and more preferably a rubber paste made of chlorine-containing rubber.

[0039] The compressed rubber layer 12 and the tensile rubber layer 13 are also formed of a rubber composition in which an uncrosslinked rubber composition, in which various rubber compounding agents are compounded and kneaded with a rubber component, is heated and pressurized to be crosslinked with a crosslinking agent. The rubber composition forming the compressed rubber layer 12 and the tensile rubber layer 13 preferably has the same rubber component as the rubber composition forming the adhesive rubber layer 11. The rubber composition forming the compressed rubber layer 12 preferably contains short fibers dispersed in the rubber component so as to be oriented in the belt width direction.

[0040] The inner reinforcing cloth 30 is provided so as to cover the inner peripheral surface of the compressed rubber layer 12. The inner reinforcing cloth 30 is made of, for example, a woven fabric, a knitted fabric, a nonwoven fabric, or the like. Examples of the fiber material forming the inner reinforcing cloth 30 include nylon fiber, polyester fiber, cotton, and aramid fiber. In order to impart adhesion to the compressed rubber layer 12, the inner reinforcing cloth 30 is preferably subjected to one or more of the following adhesion treatments before molding: an adhesion treatment in which the inner reinforcing cloth 30 is immersed in a base treatment agent containing an epoxy compound or an isocyanate compound and then heated; an adhesion treatment in which the inner reinforcing cloth 30 is immersed in an RFL aqueous solution and then heated; an adhesion treatment in which the inner reinforcing cloth 30 is immersed in rubber cement and then dried; and an adhesion treatment in which high-viscosity rubber cement is coated on the surface that is to become the V-belt main body 10 and then dried. The lower cog C is formed by covering the lower cog forming portion 121 of the compressed rubber layer 12 with this inner reinforcing cloth 30.

[0041] The outer reinforcing cloth 40 is provided so as to cover the outer peripheral surface of the tensile rubber layer 13. The outer reinforcing cloth 40 is made of, for example, a woven fabric, a knitted fabric, a nonwoven fabric, or the like. Examples of fiber materials for forming the outer reinforcing cloth 40 include nylon fiber, polyester fiber, cotton, and aramid fiber. In order to impart adhesion to the tensile rubber layer 13, the outer reinforcing cloth 40 is preferably subjected to one or more of the following adhesion treatments before molding: immersion in a base treatment agent containing an epoxy compound or an isocyanate compound and then heating, immersion in an RFL aqueous solution and then heating, immersion in rubber cement and then drying, and coating a surface of the V-belt body 10 with high viscosity rubber cement and then drying.

[0042] The cogged V-belt B according to the above embodiment can be manufactured by a known method.

[0043] In the above embodiment, a cog V-belt B having only a lower cog C is shown as the transmission belt, but the present invention is not limited to this and may be, for example, a double cog V-belt, a raw edge V-belt without cogs, a V-ribbed belt, a flat belt, a toothed belt, etc. EXAMPLES

[0044] (Cogged V-belt) A cogged V-belt of the example having the same configuration as the above embodiment was produced.

[0045] The adhesive rubber layer was formed from a rubber composition in which the rubber component CR was crosslinked by heating and pressurizing an uncrosslinked rubber composition in which FEF carbon black, a plasticizer, stearic acid, an antioxidant, a bismaleimide-based co-crosslinking agent, magnesium oxide, and zinc oxide were blended and kneaded with the rubber component CR. The blending amounts of FEF carbon black, the plasticizer, the stearic acid, the antioxidant, the bismaleimide-based co-crosslinking agent, the magnesium oxide, and the zinc oxide were 50 parts by mass, 3 parts by mass, 1 part by mass, 4 parts by mass, 5 parts by mass, 4 parts by mass, and 5 parts by mass, respectively, relative to 100 parts by mass of the rubber component CR.

[0046] The core wire was composed of a single-twist yarn made by twisting a filament bundle (12K) of PAN-based carbon fiber with a filament diameter of 7 μm and 12,000 filaments in one direction with a twist rate of 8 times per 10 cm.

[0047] The core wire protection material was applied to the core wire by immersing a filament bundle of PAN-based carbon fiber before twisting in a liquid treatment agent and then heating it. The liquid treatment agent used was a non-RFL type that uses nitrile rubber latex as a base agent, contains a crosslinking agent and filler, but does not contain resorcinol-formaldehyde condensate. The amount of core wire protection material applied was 32.5% by mass per unit length of the core wire.

[0048] After the core wire protection material was attached and twisted, the core wire was immersed in a liquid adhesive and dried to apply an adhesive coating, and the hardened product constituted the core wire adhesive layer. Chlorine-containing rubber cement was used as the liquid adhesive.

[0049] The adhesive rubber layer and the tension rubber layer were formed from different CR compositions.The inner and outer reinforcing fabrics were made of woven fabric made of nylon 66 fiber.

[0050] (Test methods and results) <Indentation elastic modulus E IT > For the cogged V-belt of the embodiment, the indentation elastic modulus E of the adhesive rubber layer and the core wire protection material exposed on the cross section along the belt width direction IT was measured using a microhardness tester at a measurement temperature of 25°C in accordance with JIS Z2255:2003.

[0051] The indentation modulus E of the adhesive rubber layer and the core wire protection material IT are 400N / mm 2 and 1320N / mm 2 Therefore, the indentation elastic modulus E of the core protection material IT is the indentation modulus of the adhesive rubber layer E IT This is 3.3 times the amount.

[0052] <High-load durability belt running test> FIG. 5 shows the layout of pulleys in a belt running test machine 50 used for a high-load durability belt running test.

[0053] This belt running test machine 50 has a drive pulley 51 and a driven pulley 52, each with a pulley diameter of 111 mm and a V-groove on its periphery, arranged at a distance from each other on the left and right, and an idler pulley 53, a flat pulley with a pulley diameter of 60 mm, which can be moved up and down and is arranged slightly above the middle part of the drive pulley 51 and driven pulley 52.

[0054] Cogged V-belt B of the embodiment was wound around drive pulley 51 and driven pulley 52, and the upper span portion between them was pressed with a dead weight DW of 108 N by contacting idler pulley 53 with the outer circumferential surface so that the upper span portion forms an angle of 140° in a side view. The ambient temperature was maintained at 80° C., and the drive pulley 51 was rotated at a rotation speed of 2900 rpm while applying a rotation load of 5.15 kW to driven pulley 52, and the belt was run for 150 hours. Cogged V-belt B of the embodiment after the belt was run was visually observed, but no core wire pop-out was observed. [Industrial Applicability]

[0055] The present invention relates to a power transmission belt. [Explanation of symbols]

[0056] B Cogged V-belt (power transmission belt) C Lower Cog F filament 10 V-belt body 11 Adhesive rubber layer 12 Compressed rubber layer 121 Lower cog forming part 13. Elastic rubber layer 20 Core Wire 21 Wire protection material 22 Core adhesive layer 30 Inner reinforcement fabric 40 Outer reinforcement fabric 50 Belt running test machine 51 Drive pulley 52 Driven pulley 53 Idler pulley

Claims

1. A power transmission belt having a rubber layer in which a carbon fiber core is embedded so as to form a spiral having a pitch in the belt width direction, A core wire protection material is attached to the core wire, the core wire protection material covering the surface of the core wire and being interposed between the carbon fiber filaments forming the core wire, A power transmission belt, wherein the indentation elastic modulus of the core wire protection material is at least three times the indentation elastic modulus of the rubber layer.

2. The power transmission belt according to claim 1, The power transmission belt, wherein the core protection material is formed of a rubber composition having a latex-derived rubber component as a matrix and containing no resorcinol-formaldehyde condensate.

3. The power transmission belt according to claim 1 or 2, The indentation elastic modulus of the core wire protection material is 900 N / mm ２ More than 2000N / mm ２ A power transmission belt as described below.

4. The power transmission belt according to any one of claims 1 to 3, The indentation elastic modulus of the rubber layer is 300 N / mm ２ More than 500N / mm ２ A power transmission belt as described below.

5. The power transmission belt according to any one of claims 1 to 4, The rubber layer of the power transmission belt is formed of a rubber composition containing a chlorine-containing rubber as a rubber component.

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