JP2016011736A - Toothed belt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toothed belt improved in bending fatigue resistance in an environment where water and oil are attached, and capable of reducing a belt width.SOLUTION: In a toothed belt 10, a plurality of core wires 12 buried in a belt body 11 and arranged in a width direction of the toothed belt 10 are formed by arranging glass fiber bundles 12b as sheath yarns on outer peripheral faces of carbon fiber bundles 12a as core yarns in a state of being in parallel with the carbon fiber bundles 12a and having no clearance between the glass fibber bundles 12b adjacent to each other, and twisting the carbon fiber bundles 12a and the glass fiber bundles 12b. In the hybrid core wires 12 formed as mentioned above and composed of the carbon fiber bundles 12a as core yarns and the glass fiber bundles 12b as the sheath yarns, the carbon fiber bundles 12a as core yarns are firmly bundled and fixed by the glass fiber bundles 12b. In a cross-sectional view of the toothed belt 10, an interval between the core wires 12 are 40% or less of a diameter of the core wires 12.

Description

  The present invention relates to a toothed belt, and more particularly to a toothed belt having improved bending fatigue resistance of a core wire of the toothed belt.

  The toothed belt is made of canvas, cord, and rubber. Since the core wire of the toothed belt is subjected to bending stress when the toothed belt is run, the strength is greatly reduced by bending. For this reason, when a narrow toothed belt is run, the strength of the belt decreases, and the toothed belt may be cut. This is because water infiltrated into the belt in an environment where water or oil adheres to the toothed belt due to loosening of the binding of the thread constituting the core due to the bending of the toothed belt, and the cross section of the core becomes flat. When the oil penetrates into the flattened core wire, the core wire swells and the tissue of the core wire breaks.

  In order to increase the belt strength of the toothed belt and prevent the toothed belt from being cut, for example, there is a method of thickening the core. However, if the core is thickened, in order to ensure the adhesion between canvas and rubber, the number of cores per unit belt width is reduced in the cross section of the toothed belt, and some rubber is interposed between adjacent cores. The belt strength cannot be increased as much as expected, and the PLD (Pitch Line Differential) of the toothed belt is increased by increasing the diameter of the cord, and the meshing with the pulley is deteriorated. Since the durability is lowered, the toothed belt cannot be narrowed. Further, in order to increase the belt strength of the toothed belt, fibers such as S glass, aramid, and carbon having high tensile strength are also used as the core wire. However, even in this case, the binding of the yarn constituting the core wire is loosened, the core wire becomes flat, the magnitude of the tensile stress acting on the individual filaments of the fiber constituting the yarn becomes non-uniform, and In an environment where water or oil adheres, the water or oil that has soaked into the belt penetrates into the flat core wire and degrades the fiber filament, so that the structure of the fiber filament is subject to excessive tensile stress. Break. For this reason, the bending reduction of the core wire is large, and the toothed belt cannot be narrowed. As described above, it is difficult to improve the bending fatigue property of the core wire of the toothed belt and reduce the width of the toothed belt.

  Then, the hybrid core wire obtained by arranging a plurality of strands as reinforcement around the core fiber of the core wire and twisting them together is known (see Patent Documents 1 and 2).

JP 2004-11076 A JP 2003-278047 A

  However, even in the case of the hybrid core wire, the core fiber is not sufficiently reinforced, and if stress is applied in the thickness direction of the toothed belt, the strength of the core wire is reduced because the core fiber is broken from the weakly reinforced tissue. There is. For this reason, the bending reduction of the core wire cannot be sufficiently improved, and the toothed belt cannot be narrowed.

  Therefore, an object of the present invention is to provide a toothed belt that can improve the bending fatigue property of the core wire even in an environment where water or oil adheres and can reduce the belt width.

  The toothed belt according to the present invention includes a core wire, the core wire includes a core yarn disposed in the center, and a sheath yarn that fixes the core yarn by covering the entire outer peripheral surface of the core yarn, and is toothed. In the cross section of the belt, the distance between the core wires is 40% or less of the diameter of the core wires.

  Since the entire outer peripheral surface of the core yarn is covered with the sheath yarn, the entire periphery of the core yarn is hardened, and there is no portion where the reinforcement of the core yarn is weak. For this reason, even when the toothed belt is subjected to bending stress, the deformation of the cross-section of the core yarn is suppressed, the perfect circular shape of the core yarn is maintained, and the core wire in an environment where water or oil adheres Bending fatigue is improved, and the toothed belt can be narrowed.

  The core yarn is a carbon fiber bundle, the sheath yarn is a glass fiber bundle, and the carbon fiber bundle is preferably fixed by twisting together with the glass fiber bundle arranged around the carbon fiber bundle. With this configuration, the carbon fiber bundle that is the core yarn is bound and fixed by the glass fiber bundle that is the sheath yarn, and there is no portion where the reinforcement of the core yarn is weak. For this reason, even when bending stress is applied to the core wire, deformation of the cross-section of the core yarn is suppressed, and stress is uniformly applied to each carbon fiber filament of the carbon fiber bundle constituting the core yarn. Therefore, the deformation of the cross-section of the core yarn of the core wire is suppressed even in an environment where water or oil adheres, so that the penetration of water or oil into the core yarn is less, and the destruction of the core yarn structure is suppressed. Bending fatigue is improved, and the toothed belt can be narrowed.

  The glass fiber bundle is preferably fixed to the outer peripheral surface of the carbon fiber bundle by an adhesive. In this case, the binding of the carbon fiber bundle by the glass fiber bundle is maintained, the deformation of the cross section of the core yarn is suppressed, and the perfect shape of the core yarn is maintained. Can increase the sex.

  The sheath yarn is made of nylon fiber, aromatic nylon fiber, glass fiber, carbon fiber, polyester fiber, aromatic polyester fiber, PPS fiber, polyimide fiber, fluorine fiber, silica fiber, PEEK fiber, PVA fiber, PE fiber and PBO fiber. It is preferably any fiber bundle selected from the group consisting of

  Further, the core yarn according to the present invention is a carbon fiber bundle, and the carbon fiber bundle may be configured to be fixed by winding a sheath yarn around the outer peripheral surface. Also in this case, the carbon fiber bundle that is the core yarn is bound and fixed by the glass fiber bundle that is the sheath yarn, and there is no portion where the reinforcement of the core yarn is weak. For this reason, even when a bending stress is applied to the core wire, the deformation of the cross-section of the core yarn is suppressed, the perfect circular shape of the core yarn is maintained, and stress is applied to each fiber filament of the carbon fiber bundle constituting the core yarn. Take evenly. For this reason, even in an environment where water or oil adheres, the penetration of water or oil into the core yarn is less, the bending fatigue of the core wire is improved, and the toothed belt can be made narrower.

  Furthermore, the toothed belt provided with the core wire according to the present invention includes a tooth cloth and a back cloth, and the core wire is fixed by being sandwiched between the tooth cloth and the back cloth. A configuration in which the interval between them is 40% or less of the diameter of the core wire may be employed. In this configuration, since the core wire is fixed by the tooth cloth and the back cloth in the thickness direction of the toothed belt, the deformation of the cross section of the core wire is suppressed even when the toothed belt is subjected to bending stress. This prevents destruction of the core tissue. For this reason, the bending fatigue property of the core wire is improved even in an environment where water or oil adheres, and the toothed belt can be narrowed.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the toothed belt which the bending fatigue property of the core wire in the environment to which water or oil adheres is improved, and a belt can be narrowed.

It is explanatory drawing which shows a part of cross section of the toothed belt which concerns on the 1st Embodiment of this invention. It is explanatory drawing which shows a part of cross section of the toothed belt which concerns on the 2nd Embodiment of this invention. It is explanatory drawing of the running test apparatus of the belt running test 1. FIG. 3 is a graph showing the results of a belt running test 1. 3 is a graph showing the results of a belt running test 1. It is a graph which shows the result of a belt bending test.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is an explanatory view showing a part of a root cross section of a toothed belt according to a first embodiment of the present invention. The toothed belt 10 is formed in an endless shape and is used by being wound around a driven and driving pulley (not shown), for example, in an internal combustion engine or the like. The torque (driving force) of the driving pulley is It is transmitted to the driven pulley by meshing transmission.

  The toothed belt 10 includes a belt main body 11 formed of an elastomer, a core wire 12 embedded in the belt main body 11 and extending along the longitudinal direction of the belt, and one surface of the belt over the entire length and width. A covering tooth cloth 13 is provided. A plurality of the core wires 12 are arranged in the width direction of the toothed belt 10. The diameter of the core wire 12 is indicated by d1, and in this embodiment, the distance g1 between the core wire 12 and the core wire 12 is adjusted to be 40% or less of the diameter d1 of the core wire 12.

  In the first embodiment, twelve core wires 12 are arranged on the outer peripheral surface of the carbon fiber bundle 12a as the core yarn so that the glass fiber bundle 12b as the sheath yarn is parallel to the carbon fiber bundle 12a. The fiber bundle 12a and the glass fiber bundle 12b are twisted together to form a core-sheath structure. The carbon fiber bundle 12a constituting the core yarn is formed by twisting, for example, 6K carbon fibers, that is, 6000 carbon fiber filaments. Around this carbon fiber bundle 12a, for example, a glass fiber bundle 12b that has been twisted is arranged side by side so that there is no gap between adjacent glass fiber bundles 12b that have been twisted, and then the carbon fiber bundle 12a and the glass fiber bundle 12b is twisted. The hybrid core wire 12 formed of the carbon fiber bundle 12a and the glass fiber bundle 12b formed in this manner is firmly fixed by binding the carbon fiber bundle 12a as the core yarn by the glass fiber bundle 12b as the sheath yarn. In addition, the carbon fiber bundle 12a, which is a core yarn, does not have a weakly reinforced portion.

  Although not shown, the tooth surface 11a of the belt main body 11 is provided with tooth portions and tooth bottom portions alternately along the longitudinal direction, and the tooth cloth 13 has outer peripheries of the tooth portions and the tooth bottom portions of the belt main body 11. It is covered. The belt body 11 is formed integrally with a tooth rubber layer 11A provided on the tooth surface 11a side and a back rubber layer 11B provided on the back surface 11b side of the belt body 11. The core 12 is disposed on the boundary surface between the tooth rubber layer 11A and the back rubber layer 11B.

  The tooth rubber layer 11A and the back rubber layer 11B are formed by vulcanizing a rubber composition. The rubber component of these rubber layers is not particularly limited. For example, H-NBR (hydrogenated nitrile rubber), fluorine rubber, NBR (nitrile rubber), a mixture thereof, or one or more types of these rubbers may be used. A mixture of these rubbers is used. Among these rubber components, HNBR is preferably used. In addition, it is preferable that the same kind of rubber is used for the rubber component of the rubber layer.

  The rubber composition of each rubber layer contains various additives such as a vulcanizing agent, an anti-aging agent, a vulcanizing aid, and carbon black in addition to the rubber component. The rubber composition of the rubber layer preferably contains a metal salt of an α, β-ethylenically unsaturated carboxylic acid such as zinc (meth) acrylate in order to improve these strengths.

  The tooth cloth 13 is a woven cloth woven by warp yarns extending in the belt width direction and weft yarns extending in the belt longitudinal direction, and is woven by, for example, a twill weave or a plain weave. As the warp yarn of the tooth cloth 13, a high-rigidity non-stretchable yarn is used. For example, a yarn composed of an aramid fiber, polyparaphenylene benzobisoxazole (PBO) fiber, carbon fiber, or a mixed fiber thereof is used. The Further, as the weft yarn, an elastic yarn is used, and for example, a crimped nylon yarn such as wooly nylon is used.

  Next, the manufacturing process of the toothed belt 10 will be described. First, a tooth cloth impregnated with rubber paste is preformed in a corrugated shape, and tooth portions and tooth bottom portions are alternately provided along a predetermined direction on the tooth cloth. Next, a separately prepared tooth rubber sheet is pressure-bonded to the pre-formed tooth cloth and integrated to prepare a tooth cloth with pre-formed rubber. At this time, the tooth rubber sheet is pressed against the tooth part of the tooth cloth with a thick wall while being pressed against the tooth bottom part.

  Next, a toothed mold used for vulcanization molding of the toothed belt 10 is prepared. The toothed mold has a cylindrical shape, the outer peripheral surface thereof has a shape that matches the shape of the tooth surface of the toothed belt 10, and concave portions and convex portions are alternately provided along the circumferential direction. On the outer peripheral surface of the toothed mold, first, a tooth cloth with a pre-molded rubber is wound so that each tooth portion is disposed inside each recess. In addition, each tooth part does not usually have a shape that completely coincides with the recessed part, and there is a gap between the tooth part and the recessed part.

  Next, the core wire 12 is spirally wound on the tooth rubber sheet of the pre-formed rubber-equipped tooth cloth. As described above, the core 12 has the glass fiber bundle 12b twisted as a sheath yarn disposed on the outer peripheral surface of the twisted carbon fiber bundle 12a, and the carbon fiber bundle 12a and the glass fiber bundle 12b are twisted together. Thus, a hybrid core wire having a core-sheath structure in which the carbon fiber bundle 12a is a core yarn and the glass fiber bundle 12b is a sheath yarn is formed. A back rubber sheet having a predetermined thickness is wound on the wound core wire 12. The toothed mold around which the tooth cloth with pre-molded rubber is wound is accommodated in a vulcanizing pot (not shown).

  In the vulcanizer, the pre-formed rubber tooth cloth wound around the toothed mold is heated by, for example, steam and pressurized from outside to inside by a vulcanizing bag or the like provided in the vulcanizer. The By this pressurization and heating, each rubber sheet is pressed inward with increased fluidity, and each rubber sheet is vulcanized to integrate the rubber sheet, tooth cloth and core wire. Is obtained. The belt slab is removed from the toothed mold, cut after polishing, and becomes a toothed belt 10. In this embodiment, the toothed belt 10 is molded by using the above-described pre-formed rubber tooth cloth, and the distance g1 between the core wire 12 and the core wire 12 is adjusted to 40% or less of the diameter d1 of the core wire 12. Is done.

  In the toothed belt 10 according to the first embodiment of the present invention, in the toothed belt 10 including the core wire 12, the carbon fiber bundle 12a as the core yarn is entirely covered by the glass fiber bundle 12b as the sheath yarn. Therefore, the entire area around the carbon fiber bundle 12a is hardened, and there is no weak reinforcement point of the carbon fiber bundle 12a. For this reason, even when the toothed belt 10 is subjected to bending stress, the deformation of the cross section of the carbon fiber bundle 12a is suppressed, the perfect circular shape of the carbon fiber bundle 12a is maintained, and water or oil adheres to the environment. Thus, the bending fatigue property of the core 12 is improved, and the toothed belt 10 can be narrowed.

  Further, in this embodiment, the carbon fiber bundle 12a of the core yarn is fixed by being twisted together with the glass fiber bundle 12b of the sheath yarn arranged around the carbon fiber bundle 12a, so that the carbon fiber that is the core wire The bundle 12a is firmly bound and fixed by the glass fiber bundle 12b which is a sheath yarn, and the carbon fiber bundle 12a is surely reinforced by any one of the glass fiber bundles 12b, and there is a weakly reinforced portion on the outer peripheral surface of the carbon fiber bundle 12a. Absent. For this reason, even when bending stress is applied to the core wire 12, the deformation of the cross section of the carbon fiber bundle 12a is suppressed, and the stress is uniformly applied to each carbon fiber filament constituting the carbon fiber bundle.

  In the present embodiment, the core 12 has a core-sheath structure in which the carbon fiber bundle 12a is a core yarn and the glass fiber bundle 12b is a sheath yarn by twisting the carbon fiber bundle 12a and a plurality of glass fiber bundles 12b. In order to prevent the deformation of the structure of the core wire 12 by fixing the twisted core wire 12 and to improve the adhesion between the core wire 12 and the belt body 11, the twisted core wire 12 is twisted. The core wire 12 may be fixed with an adhesive such as rubber paste. In this case, the twisted core wire is dipped in rubber paste, and then the dried core wire is spirally wound on the tooth rubber sheet of the pre-formed rubber tooth fabric wound around the toothed mold. In this case, the binding of the carbon fiber bundle by the glass fiber bundle is maintained, the deformation of the cross section of the core yarn is further suppressed to maintain the perfect circular shape of the core yarn, and the bonding with the belt body that is the matrix rubber Can increase the sex. Moreover, it is possible to prevent water and oil from permeating into the core wire and to prevent swelling of the core wire.

  In the present embodiment, the carbon fiber bundle 12a constituting the core yarn of the core wire 12 is fixed by being bound by a plurality of glass fiber bundles 12b that are sheath yarns. The core yarn may be fixed by winding a single or a plurality of glass fiber bundles around the outer peripheral surface of the carbon fiber bundle to be formed. Also in this case, the carbon fiber bundle that is the core yarn is bound and fixed by the glass fiber bundle that is the wound yarn, and the carbon fiber bundle is always reinforced by any one of the glass fiber bundles. There are no weak points. For this reason, even when a bending stress is applied to the core wire, the deformation of the cross section of the core yarn is suppressed, the perfect circular shape of the core wire is maintained, and the stress is uniformly applied to each carbon fiber filament constituting the core yarn. And the bending fatigue | exhaustion property of the core wire in the environment where water or oil adheres improves, and it becomes possible to narrow a toothed belt.

  The wound yarns in this case are nylon fiber, aromatic nylon fiber, carbon fiber, polyester fiber, aromatic polyester fiber, PPS fiber, polyimide fiber, fluorine fiber, silica fiber, PEEK fiber, PVA fiber, PE fiber, PBO Examples thereof include a fiber bundle made of fibers and the like.

  In the first embodiment, the carbon fiber bundle 12a is used as the core yarn of the core wire 12, but a fiber bundle other than the carbon fiber may be used as the core yarn. Moreover, in this embodiment, although the glass fiber bundle 12b was used as a sheath thread which fixes a core yarn, you may use fiber bundles other than a glass fiber bundle. For example, as sheath thread, nylon fiber, aromatic nylon fiber, carbon fiber, polyester fiber, aromatic polyester fiber, PPS fiber, polyimide fiber, fluorine fiber, silica fiber, PEEK fiber, PVA fiber, PE fiber, PBO fiber, etc. The fiber bundle which becomes is mentioned.

  Next, a toothed belt according to a second embodiment of the present invention will be described with reference to FIG. FIG. 2 is an explanatory view showing a part of a root cross section of a toothed belt according to a second embodiment of the present invention. The second embodiment is different from the first embodiment in that a tooth cloth and a back cloth are used as means for reinforcing and fixing the core wire. Hereinafter, the difference between the second embodiment and the first embodiment will be described.

  As shown in FIG. 2, the toothed belt 20 according to the second embodiment of the present invention includes a belt main body 21 and a core wire 22 embedded in the belt main body 21 and extending along the longitudinal direction of the belt. As shown in FIG. 2, a plurality of core wires 22 are arranged in the width direction of the toothed belt 20. The belt body 21 includes a tooth cloth 23a on the tooth surface 21a side and a back cloth 23b on the back surface 21b side. In the present embodiment, the core wire 22 is sandwiched between the tooth cloth 23a and the back cloth 23b. Furthermore, the tooth cloth 23a and the back cloth 23b are fixed to the core wire 22 and the belt body 21 by adhesion. Here, the diameter of the core wire 22 is indicated by d2, and the distance g2 between the core wire 22 and the core wire 22 is adjusted to be 40% or less of the diameter d2 of the core wire 22.

  In the present embodiment, the core wire 22 is, for example, a twisted 12K carbon fiber bundle. The tooth cloth 23a and the back cloth 23b are woven fabrics woven by warp yarns extending in the belt width direction and weft yarns extending in the belt longitudinal direction, and are woven by, for example, twill weave or plain weave. The tooth cloth 23a and the back cloth 23b may be the same woven cloth or different woven cloths. Further, the thicknesses may be different. Further, the tooth cloth 23a and the back cloth 23b may be impregnated with an adhesive such as rubber glue or RFL liquid in order to adhere to the core wire 22 and the belt body 21.

  The toothed belt 20 is molded by the same manufacturing process as in the first embodiment (however, the back cloth 23b is wound instead of the back rubber sheet 11B), and thereby the core wire 22 and the core wire of the toothed belt 20 are formed. The distance g2 with respect to 22 is adjusted to 40% or less of the diameter d2 of the core wire 22.

  In the toothed belt 20 according to the second embodiment of the present invention, the toothed belt 20 including the core wire 22 includes the tooth cloth 23a and the back cloth 23b, and the core wire 22 is sandwiched between the tooth cloth 23a and the back cloth 23b. Thus, the core wire 22 is fixed by the tooth cloth 23a and the back cloth 23b in the thickness direction of the toothed belt 20. Since the bending stress is applied in the thickness direction of the toothed belt 20, even if the toothed belt 20 receives bending stress, the core wire 22 is caused by the tooth cloth 23a and the back cloth 23b in the direction receiving bending stress. Since it is reinforced, deformation of the cross section of the core wire 22 is suppressed and deformation of the tissue of the core wire 22 is prevented. For this reason, the bending fatigue property of the core wire 22 in an environment where water or oil adheres is improved, and the toothed belt 20 can be narrowed.

  Examples are shown below as specific examples of the present invention, but the present invention is not limited to the following examples.

First, the toothed belts of Examples 1, 2, and 4 and Comparative Examples 1 to 4 shown below were manufactured according to the first embodiment. Further, the toothed belt of Example 3 was manufactured according to the second embodiment.
Specifically, H-NBR rubber is used as the rubber composition constituting the belt body, aramid canvas is used as the tooth cloth, each tooth shape has an arc tooth shape, a tooth pitch of 8 mm, a belt length of 880 mm, and a belt width of 19.1 mm. A belt with a belt was obtained. Further, an aramid canvas used as a tooth cloth was used as the back canvas of Example 3.

<Example 1>
In Example 1, a hybrid core wire in which a glass fiber bundle was disposed around a 6K carbon fiber bundle and twisted together was used as the core wire of the toothed belt. Here, 6K means a fiber bundle (strand) in which 6000 carbon fiber filaments are bundled.
The hybrid core used in the toothed belt of Example 1 was prepared as follows. First, an untwisted 6K carbon fiber bundle (Trekker RT300-6000 manufactured by Toray Industries, Inc.) was dipped in an RFL treatment solution and dried, and then twisted after being dried. Separately, three fiber bundles (micro glass R rubber cord manufactured by Nippon Sheet Glass Co., Ltd.) bundled with 200 non-twisted glass fiber filaments for reinforcement are drawn and dipped in an RFL treatment solution and dried. Two glass fiber bundles were twisted to form one glass fiber bundle. Next, 12 glass fiber bundles prepared separately are arranged around the carbon fiber bundle prepared first, the whole is twisted, the carbon fiber bundle is used as the core yarn, and the glass sheath is used as the sheath yarn. A hybrid cord of structure was created.
And the toothed belt was created using the said core wire. In the cross section of the toothed belt obtained in Example 1, the distance between the core wires was 26% of the diameter of the core wires.

<Example 2>
In Example 2, the hybrid cord prepared in Example 1 was dipped in an adhesive (Chemlock 233 manufactured by Road Far East Co., Ltd.) and dried to create a hybrid cord coated with the adhesive. The toothed belt of Example 2 was created using the wire. In the cross section of the toothed belt obtained in Example 2, the distance between the core wires was 25% of the diameter of the core wires.

<Example 3>
In Example 3, a non-twisted 12K carbon fiber bundle (Torayca RT300-12000 manufactured by Toray Industries, Inc.) was dipped in an RFL treatment solution and dried, and then the teeth of Example 3 were used using a core wire to which twisted yarn was applied after drying. A belt with a mark was created. In the cross section of the toothed belt obtained in Example 3, the distance between the core wires was 26% of the diameter of the core wires.

<Example 4>
In Example 4, a toothed belt was created using the hybrid core wire of Example 1. However, the tooth obtained in Example 4 was obtained by reducing the number of core wires to be spirally wound on the tooth rubber sheet of the pre-formed rubber tooth cloth wound around the toothed mold as compared with Example 1. In the cross section of the belt, the distance between the cords was adjusted to 40% of the cord diameter.

<Comparative Example 1>
As Comparative Example 1, 11 glass fiber bundles separately prepared in Example 1 were twisted to create a core wire, and a toothed belt of Comparative Example 1 was prepared using the concentric wire. In the cross section of the toothed belt obtained in Comparative Example 1, the distance between the core wires was 26% of the diameter of the core wires.

<Comparative Example 2>
As Comparative Example 2, an untwisted 12K carbon fiber bundle (Torayca RT300-12000 manufactured by Toray Industries, Inc.) is dipped in an RFL treatment solution and dried. After drying, a twisted yarn is applied to create a core wire, and a concentric wire is used. The toothed belt of Comparative Example 2 was prepared. In the cross section of the toothed belt obtained in Comparative Example 2, the distance between the core wires was 26% of the diameter of the core wires.

<Comparative Example 3>
As Comparative Example 3, a toothed belt of Comparative Example 3 was prepared using the 6K carbon fiber bundle prepared as the core yarn in Example 1 as it was for the core wire. In the cross section of the toothed belt obtained in Comparative Example 3, the interval between the core wires was 30% of the diameter of the core wires.

<Comparative Example 4>
In Comparative Example 4, a toothed belt was prepared using the hybrid core wire of Example 1. However, it was obtained in Comparative Example 4 by further reducing the number of core wires to be wound spirally on the tooth rubber sheet of the pre-formed rubber tooth cloth wound around the toothed mold than in Example 4. In the cross section of the toothed belt, the distance between the cores was 58% of the diameter of the core.

[Belt running test 1 (oil resistance multiple bending test)]
The toothed belts obtained in Examples 1 to 4 and Comparative Examples 1 to 4 were subjected to a belt running test 1 (oil resistance multi-bending test) in an environment where high temperature oil mist adheres, and each toothed belt was oil resistant. The bending performance was evaluated.

  FIG. 3 shows a running test apparatus 30 used in the belt running test 1 performed as the belt performance evaluation. The traveling test apparatus 30 includes a driven toothed pulley 31 and a driven toothed pulley 32 having a number of teeth of 20 teeth (8 mm pitch), and an idler pulley 33 having a pulley diameter of 45 mm, and stores oil 34 at the bottom. . In the belt running test 1, the toothed belt is wound around the pulley 31 with the driven tooth and the pulley 32 with the driving tooth, and the pulley 32 with the driving tooth is rotated in the direction of the arrow 3X at 6000 rpm, while no load is applied. Traveled for hours. In the belt running test 1, the impeller 35 that is coaxially attached to the side surface of the pulley 31 with the driven tooth located at the lowermost portion and contacts the oil 34 moves in the direction of the arrow 3X in conjunction with the rotational movement of the pulley 32 with the driving tooth. The oil 34 rotated and heated up to a predetermined temperature by the heater 36 was spun up at 130 ° C. in an environment where oil mist adhered to the belt.

  The toothed belt after running was attached to a tensile testing machine, a tensile test was performed at a speed of 50 mm / min at room temperature, and the breaking strength of the toothed belt was measured. Similarly, a new toothed belt was subjected to a tensile test, and the breaking strength of the toothed belt was measured. Then, the breaking strength of the toothed belt after the belt running test 1 was divided by the breaking strength of the new toothed belt to calculate the residual strength retention rate of the toothed belt after running.

  FIG. 4 shows the results of Examples 1 to 3 and Comparative Examples 1 to 3 of the belt running test 1. Comparative Example 1 with only glass fiber bundle as core, Comparative Example 2 with only 12K carbon fiber bundle as core, and Comparative Example 3 with only 6K carbon fiber bundle as core, 6K in the core yarn Tooth of Example 1 using a hybrid core wire having a core-sheath structure in which a glass fiber bundle is used for the carbon fiber bundle and the sheath yarn of Example 1, and the tooth of Example 2 in which the hybrid core wire of Example 1 is coated with an adhesive An implementation in which only the belt with a twelve belt and a 12K carbon fiber bundle are used as a core wire, and the concentric wire is sandwiched between the tooth cloth and the back cloth so that the concentric wire is fixed by the tooth cloth and the back cloth in the thickness direction of the toothed belt The toothed belt of Example 3 clearly showed a high residual strength retention. Thus, the toothed belts of Example 1 and Example 2 showed a higher residual strength retention rate than the toothed belts of Comparative Examples 1 to 3 in which only the glass fiber bundle or the carbon fiber bundle was the core wire. Since the carbon fiber bundle of the core yarn is bundled by the glass fiber bundle of the sheath yarn and the periphery is hardened, the penetration of oil into the inside of the core wire is suppressed, and the deformation of the cross section of the core yarn is suppressed and the load This is thought to be due to the fact that it is difficult to be dispersed. In addition, the toothed belt of Example 3 having only a 12K carbon fiber bundle as the core wire showed high residual strength retention because the concentric wire was fixed by the tooth cloth and the back cloth in the thickness direction of the toothed belt. Therefore, it is considered that the penetration of oil into the core wire is similarly suppressed, the deformation of the cross section of the core wire is suppressed, and the load is hardly dispersed.

  FIG. 5 shows the results of Example 1, Example 4 and Comparative Example 4 of the belt running test 1. The toothed belts of Example 1, Example 4 and Comparative Example 4 are made of the same hybrid core wire having a core-sheath structure using a 6K carbon fiber bundle as a core yarn and a glass fiber bundle as a sheath yarn, and other belt materials are also available. The same and the difference is the spacing between the cords in the cross section of the toothed belt. From the results of FIG. 5, the distance between the core wires in the cross section of the toothed belt using the core-sheath hybrid core wire using 6K carbon fiber bundle as the core yarn and glass fiber bundle as the sheath yarn is the diameter of the core wire. The toothed belts of Example 1 and Example 4 of 40% or less of Comparative Example 4 in which the distance between the cords in the cross section of the toothed belt was set to 58% of the cord diameter using the same hybrid cord. The residual strength retention rate was clearly higher than that of other toothed belts. This is because when the distance between the cores in the cross section of the toothed belt is larger than 40% of the diameter of the core, the ratio of tooth rubber and back rubber having a lower elastic modulus than the core is relatively increased. The wire is greatly affected by the rubber compression in the belt thickness direction due to the bending of the toothed belt, the cross section of the core wire is deformed flat, the oil penetrates into the inside of the core wire, and the load applied to the core wire is dispersed, It is considered that the stress is applied unevenly, and the carbon fiber filaments are sequentially cut from the carbon fiber filaments that are swollen / degraded by oil and overloaded. On the other hand, the toothed belts of Example 1 and Example 4 show a high residual strength retention rate, but when the distance between the cores in the cross section of the toothed belt is 40% or less of the diameter of the cores, This is probably because it is hardly affected by rubber compression in the belt thickness direction due to the bending of the belt.

  Thus, the core wire of the toothed belt is a hybrid core wire having a core-sheath structure in which the carbon fiber bundle is the core yarn and the glass fiber bundle is the sheath yarn, and the interval between the core wires in the cross section of the toothed belt is The diameter of the core is 40% or less, or the toothed belt has a core made of a tooth cloth and a back cloth and a carbon fiber bundle, and the core is sandwiched between the tooth cloth and the back cloth. It was shown that if the distance between the core wires in the cross section is 40% or less of the diameter of the core wire, the deformation of the cross section of the core wire is suppressed and the bending fatigue property in an environment where oil adheres is improved. .

[Belt running test 2 (water injection multi-bending test)]
Next, for the toothed belts of Example 1 and Comparative Example 1, belt running test 2 (water injection multi-bending test) was performed using the same running test apparatus 30 as belt running test 1. However, the oil 34 was not stored in the bottom of the traveling test apparatus 30 and the impeller 35 was removed. Then, while injecting water (1 L / hr) into the belt engagement portion of the driven pulley 31 positioned at the lowest position in the 80 ° C. environment, the pulley 32 with the driving teeth is rotated at 6000 rpm in the direction of the arrow 3X, and no load is applied. In this state, the toothed belt was run for 200 hours.

  And the residual strength retention of the toothed belt after running was calculated by the method described in [0051]. Regarding the results of the belt running test 2, the residual strength retention rates of the toothed belts of Example 1 and Comparative Example 1 were 90% and 50%, respectively.

  In this way, the core wire of the toothed belt is a hybrid core wire having a core-sheath structure in which the carbon fiber bundle is the core yarn and the glass fiber bundle is the sheath yarn, so that deformation of the cross section of the core wire is suppressed, It was shown that the bending fatigue property is improved even in an environment where the slag adheres.

[Belt bending test]
In order to confirm the improvement of the bending performance of the core wire, as a belt bending test, the toothed belts of Examples 1 and 2 and Comparative Examples 1 and 2 were bent by about 180 ° three times with bare hands, and then described in [0051]. A tensile test was performed, and the residual strength retention rate for each new toothed belt before bending was calculated.

  FIG. 6 shows the result of the belt bending test. The residual strength retention rate of the toothed belt of Comparative Example 1 using only the glass fiber bundle as the core and the toothed belt of Comparative Example 2 using only the 12K carbon fiber bundle as the core decreased to 48% and 14%, respectively. In comparison with the above, the adhesive (rubber) is applied to the toothed belt of Example 1 and the hybrid core of Example 1 using the core-sheath hybrid core having the carbon fiber bundle as the core yarn and the glass fiber bundle as the sheath yarn. The residual strength retention rate of the toothed belt of Example 2 using the core wire coated with adhesive) is 64% and 95%, respectively, and the bending performance is superior to the toothed belts of Comparative Example 1 and Comparative Example 2. Turned out to be. In particular, the toothed belt of Example 2 showed almost the same strength as a new article even when it was bent excessively. This is because, in the cross section of the toothed belt, the distance between the cords is 40% or less of the diameter of the cords, and the hybrid cords further increase the focusing of the carbon fiber bundles of the core yarn around the cords. This is probably because the periphery of the core wire was firmly fixed by covering with rubber paste (rubber latex), and the deformation of the core wire tissue was sufficiently prevented.

10, 20 Toothed belt 11, 21 Belt body 12, 22 Core wire 12a Carbon fiber bundle 12b Glass fiber bundle 13, 23a Tooth fabric 23b Back cloth d1, d2 Core diameter g1, g2 Spacing between core wires

<Example 1>
In Example 1, a hybrid core wire in which a glass fiber bundle was disposed around a 6K carbon fiber bundle and twisted together was used as the core wire of the toothed belt. Here, 6K means a fiber bundle (strand) in which 6000 carbon fiber filaments are bundled.
The hybrid core used in the toothed belt of Example 1 was prepared as follows. First, an untwisted 6K carbon fiber bundle (Treka (registered trademark) T300-6000 manufactured by Toray Industries, Inc. ) was dipped in an RFL treatment solution and dried, and then twisted. Separately, three fiber bundles (micro glass (registered trademark) rubber cord manufactured by Nippon Sheet Glass Co., Ltd. ) bundled with 200 untwisted glass fiber filaments for reinforcement are drawn together, dipped in an RFL treatment solution, dried, and dried. Later, the three glass fiber bundles were twisted to form one glass fiber bundle. Next, twelve separately prepared glass fiber bundles are arranged around the carbon fiber bundle prepared first, the whole is twisted, the carbon fiber bundle is used as the core yarn, and the glass fiber bundle is used as the kite yarn. A hybrid cord of structure was created.
And the toothed belt was created using the said core wire. In the cross section of the toothed belt obtained in Example 1, the distance between the core wires was 26% of the diameter of the core wires.

<Example 3>
In Example 3, an untwisted 12K carbon fiber bundle (Toray Industries, Inc., Torayca (registered trademark) T300-12000) was dipped in an RFL treatment solution, dried, and then dried using a cored wire with twisted yarn. The toothed belt of Example 3 was made. In the cross section of the toothed belt obtained in Example 3, the distance between the core wires was 26% of the diameter of the core wires.

<Comparative Example 2>
As Comparative Example 2, an untwisted 12K carbon fiber bundle (Toray Industries, Inc., Torayca (registered trademark) T300-12000) was dipped in an RFL treatment solution and dried, and after drying, a twisted yarn was applied to create a cord. The toothed belt of Comparative Example 2 was created using the wire. In the cross section of the toothed belt obtained in Comparative Example 2, the distance between the core wires was 26% of the diameter of the core wires.

Claims (6)

In a toothed belt with a core wire,
The core wire includes a core yarn disposed in the center and a sheath yarn that fixes the core yarn by covering the entire outer peripheral surface of the core yarn,
A toothed belt characterized in that in the cross section of the toothed belt, the distance between the core wires is 40% or less of the diameter of the core wires. The core yarn is a carbon fiber bundle, the sheath yarn is a glass fiber bundle,
The toothed belt according to claim 1, wherein the carbon fiber bundle is fixed by being twisted together with the glass fiber bundle disposed around the carbon fiber bundle.   The toothed belt according to claim 2, wherein the glass fiber bundle is fixed to an outer peripheral surface of the carbon fiber bundle by an adhesive.   The sheath yarn is nylon fiber, aromatic nylon fiber, glass fiber, carbon fiber, polyester fiber, aromatic polyester fiber, PPS fiber, polyimide fiber, fluorine fiber, silica fiber, PEEK fiber, PVA fiber, PE fiber and PBO fiber. The toothed belt according to claim 1, which is any fiber bundle selected from the group consisting of: The core yarn is a carbon fiber bundle,
The toothed belt according to claim 1, wherein the carbon fiber bundle is fixed by winding the sheath yarn around an outer peripheral surface. In a toothed belt with a core wire,
The toothed belt comprises a tooth cloth and a back cloth;
The core wire is fixed by being sandwiched between the tooth cloth and the back cloth,
A toothed belt characterized in that in the cross section of the toothed belt, the distance between the core wires is 40% or less of the diameter of the core wires.

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