JP2019116969A - V-ribbed belt and its process of manufacture - Google Patents

Abstract

To provide a V-ribbed belt capable of keeping a power transmission performance even in a case of operation in water.SOLUTION: This invention manufactures a V-ribbed belt comprising a compression rubber layer including an elongation layer forming a belt back-face and several ribs formed at one surface of this elongation layer and arranged in a belt width direction and a core body buried between said elongation layer and said compression rubber layer. said rib part contacts to a pulley at opposing two side surfaces and engages it in friction, includes several water absorptive threads buried there while being spaced apart in a belt longitudinal direction, each of the water absorptive threads extends from one side surface of the rib part toward the other opposite side surface at a surface direction substantially perpendicular to a belt thickness direction and in a direction inclined in respect a belt width direction and passes through in a belt width direction, both ends of each of the water absorptive thread are exposed at each of the side surfaces of the rib part. It is also available that the water absorptive thread is included at a central region of the rib part in a belt thickness direction. It is also available that an angle of said water absorptive thread in respect to the belt width direction is about 30° to 80°.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a V-ribbed belt used to drive an accessory of an automobile engine and a method of manufacturing the same, and more particularly to a V-ribbed belt having high power transmission performance even when traveling in rainy weather and a method of manufacturing the same.

  V-ribbed belts are widely used for power transmission of accessory drives of automobile engines such as air compressors and alternators, and high power transmission performance is always required regardless of the weather. However, when traveling on a rainy day (when exposed to water) or the like, water intrudes into the engine room, and water intervenes between the friction transmission surface of the belt and the pulley to lower the coefficient of friction. There is a problem that the drive slips and the power transmission performance is reduced. To solve such problems, a method of absorbing water from the contact surface by a water absorbing fiber has been proposed as a means for removing the water present between the friction transmission surface of the belt and the pulley.

  JP-A-2014-147347 (Patent Document 1) discloses a V-ribbed belt provided with a compressed rubber layer comprising a rubber component containing a polymer component, water-absorbing short fibers such as cotton short fibers, and a surfactant. JP-A-2014-209028 (Patent Document 2) discloses a V-ribbed belt having a friction transmission surface covered with a knitted fabric knitted with a polyester-based composite yarn and a cellulose-based natural spun yarn. WO 2015/177953 (patent document 3) discloses a V-ribbed belt coated with a water absorbing cloth composed of a spun yarn of polyethylene terephthalate, polyamide or aramid on the friction transmission surface. In these V-ribbed belts, the water absorbing fibers of the compressed rubber layer are hydrated to remove water present between the friction transmission surface and the pulleys.

  However, in the V-ribbed belts of Patent Documents 1 to 3, since there is no means for efficiently draining the absorbed water, the effect is reduced when the water-absorbent fibers absorb water to some extent.

  On the other hand, a method of draining from the contact surface by a drainage path has also been proposed. In JP 2009-030717 A (Patent Document 4), a plurality of recessed portions (grooves) are provided on the rib formation surface to form a noncontact region not in contact with the pulley, and this noncontact region is formed when water is covered V-ribbed belts are disclosed which allow water to flow through. Further, in JP 2009-281555 A (Patent Document 5), there is provided a V-ribbed belt in which at least one recess extending in the longitudinal direction of the belt is provided on both side surfaces of the rib portion and water can be discharged using this recess as a drainage groove. It is disclosed. Further, Japanese Patent Application Laid-Open No. 2006-046392 (Patent Document 6) discloses a V-ribbed belt having a plurality of water drainage holes penetrating from the valleys of the V-rib to the back surface. In these V-ribbed belts, water is drained through a drainage path to eliminate water present between the friction transmission surface and the pulleys.

  However, even with the V-ribbed belts of Patent Documents 4 to 6, it is difficult to efficiently guide the water to the drainage path, and it is not possible to efficiently remove the water between the friction transmission surface and the pulley.

  In addition, the V-ribbed belt provided with the compression section formed with the elastic material which encloses the reinforcement body (cord | cord | chord) arrange | positioned to the substantially horizontal direction of a belt is disclosed to Unexamined-Japanese-Patent No. 2016-518557 (patent document 7). It is done. In this V-ribbed belt, the compression of the elastic material causes the reinforcement to project relative to the rest of the compression section, thereby achieving stability of the effective coefficient of friction under both dry and wet conditions. That is, the coefficient of friction in the dry state is reduced by the surface area of the V-ribs due to the reinforcement. Furthermore, the protrusion of the reinforcing body increases the coefficient of friction in wet conditions by the interruption effect of the projections on the lubrication of water between the friction transmission surface and the pulley.

  However, Patent Document 7 does not describe the removal of water between the friction transmission surface and the pulley. Furthermore, in friction transmission belts such as V-ribbed belts, it is important from the practical point of view to balance power transmission performance and durability, but it may be because the hydrophilic material has low affinity with the belt material, If the power transmission performance during traveling is improved, the durability of the belt tends to decrease. Therefore, in the V-ribbed belt, the power transmission performance at the time of running on water and the durability are in a trade-off relationship, and it is difficult to achieve both.

JP, 2014-167347, A (claim 1, example) Unexamined-Japanese-Patent No. 2014-209028 (Claim 1) WO 2015/177953 (Claims 1 and 4 and Example) JP, 2009-030717, A (claim 1) JP, 2009-281555, A (claim 1, paragraph [0010]) Unexamined-Japanese-Patent No. 2006-046392 (Claim 1) JP-A-2016-518557 (claim 1, paragraph [0007])

  Therefore, an object of the present invention is to provide a V-ribbed belt capable of maintaining the power transmission performance even while traveling in the water, and a method of manufacturing the same.

  Another object of the present invention is to provide a V-ribbed belt capable of achieving both the durability of the belt and the power transmission performance when running on water, and a method of manufacturing the same.

  As a result of intensive studies to achieve the above-mentioned problems, the inventor of the present invention embeds a plurality of water absorbing yarns in the rib portion constituting the compression rubber layer of the V-ribbed belt at intervals in the longitudinal direction of the belt, and the water absorption By arranging the yarns along a direction inclined with respect to the belt width direction and exposing both end portions of the water-absorbent yarns on the side surfaces of the rib portion, power transmission performance can be maintained even during water running. And completed the present invention.

  That is, the V-ribbed belt of the present invention comprises a stretch layer forming the back of the belt, a compressed rubber layer having a plurality of rib portions formed on one side of the stretch layer and aligned in the belt width direction, and the stretch layer And a core embedded between the compressed rubber layer, wherein the rib portion is in frictional engagement with the pulley on two opposite side faces and is spaced along the belt longitudinal direction And a plurality of water absorbing yarns embedded in the belt, each water absorbing yarn being in the belt width direction from one side surface of the rib portion to the other side surface opposed in the surface direction substantially perpendicular to the belt thickness direction. The both ends of each water-absorbent yarn are exposed at each side of the rib portion, extending in a direction inclined with respect to the belt and penetrating in the belt width direction. The interval between the plurality of water absorbing yarns may be about 2 to 15 mm. The V-ribbed belt may include a water absorbing yarn in the central region of the rib in the belt thickness direction. The angle of the water absorbing yarn with respect to the belt width direction may be about 5 to 85 °. The average fiber diameter of the water absorbing yarn may be about 0.1 to 1 mm. The water absorbing yarn may be a multifilament yarn having an average fiber diameter of 8 μm or less of a single fiber. The water-absorbent yarn may be at least one selected from the group consisting of cellulosic fibers, polyamide fibers and polyester fibers.

  In the present invention, a winding step of sequentially winding a sheet for forming a stretch layer, a core, and a sheet for forming a compressed rubber layer on a cylindrical drum, and a wound laminated sheet is used as a mold. Also included is the method for producing the V-ribbed belt, which comprises a vulcanizing and forming step of pressing and molding the unvulcanized rubber sheet by vulcanization. In this manufacturing method, the method of winding the sheet for forming the compressed rubber layer is the first unvulcanized rubber sheet for forming the compressed rubber layer and the second unvulcanized for forming the compressed rubber layer. A method of winding a laminated sheet having a water absorbing yarn temporarily fixed at a predetermined angle with respect to the longitudinal direction of the sheet between rubber sheets, and at a predetermined angle with respect to the longitudinal direction of the sheet A method of sequentially winding a first unvulcanized rubber sheet for forming a compressed rubber layer on which a water absorbing yarn is temporarily fixed and a second unvulcanized rubber sheet for forming a compressed rubber layer, Or a method for sequentially winding a first compressed rubber layer sheet and a second compressed rubber layer sheet on which a water absorbing yarn is temporarily fixed at a predetermined angle with respect to the length direction of the sheet. It is also good.

  In the present invention, a plurality of water absorbing yarns are embedded in the rib portion constituting the compression rubber layer of the V-ribbed belt at intervals in the longitudinal direction of the belt, and the water absorbing yarns are inclined in the width direction of the belt. Since both ends of the water absorbing yarn are exposed at the side surfaces of the rib portion while being disposed along with the water absorbing yarn, the water present between the friction transmission surface and the pulley is efficiently absorbed (hydrated), And it has a function which can be drained, and it can control the slip between a belt and a pulley even at the time of water running, and can improve power transmission performance. Furthermore, by adjusting the fiber diameter and the embedding mode of the water absorbing yarn, it is possible to achieve both the durability of the belt and the power transmission performance when running on water.

FIG. 1 is a schematic perspective view showing an example of the V-ribbed belt of the present invention. FIG. 2 is a cross-sectional view of a rib portion in a region where the water absorbing yarn is embedded in the V-ribbed belt of FIG. FIG. 3 is a schematic view showing the V-ribbed belt of the present invention mounted on a pulley. FIG. 4 is a schematic view for explaining the flow of water in the rib portion. FIG. 5 is a schematic view showing a layout of a water injection transfer performance test in the example. FIG. 6 is a schematic view showing the layout of the endurance running test in the embodiment.

[V-ribbed belt]
The V-ribbed belt of the present invention comprises a stretch layer forming the back of the belt, a compressed rubber layer having a plurality of rib portions formed on one side of the stretch layer and aligned in the belt width direction, the stretch layer, and the stretch layer It is a V-ribbed belt provided with a core embedded between a compression rubber layer, and a plurality of water absorbing yarns are embedded at intervals in the rib portion. The core body may be a plurality of core wires extending along the longitudinal direction of the belt and embedded at intervals in the widthwise direction of the belt. In the V-ribbed belt of the present invention, an adhesive layer may be provided between the compression rubber layer and the expansion layer as needed in order to improve the adhesion between the core and the expansion layer or the compression rubber layer. The adhesive layer may be provided by embedding the core in the adhesive layer, and the core may be embedded between the compressed rubber layer and the adhesive layer or between the adhesive layer and the stretching layer. It may be.

  An example of the V-ribbed belt of the present invention will be described with reference to FIGS. FIG. 1 is a schematic perspective view showing an example of a V-ribbed belt cut in the belt width direction, and FIG. 2 is a cross-sectional view of a rib portion in a region where a water absorbing yarn is embedded in the V-ribbed belt of FIG. . In this example, the V-ribbed belt has a compression rubber layer 1 and an adhesive layer 3 in which a plurality of core wires 4 extending along the length direction are embedded sequentially from the lower surface (inner peripheral surface) to the upper surface (rear surface) of the belt. And a stretch layer 5 formed of a rubber composition.

  Specifically, the compression rubber layer 1 has rib portions 1a (in FIG. 1, the number of ribs is 3) extending in a plurality of rows along the longitudinal direction of the belt on the inner peripheral surface of the belt main body. The cross-sectional shape in the direction orthogonal to the longitudinal direction of the portion 1a is such that the width decreases from the outer circumferential side of the belt (the side not having a rib portion and not frictionally engaged with the pulley) toward the inner circumferential side The rib portions 1a are frictionally engaged in contact with the pulleys at two opposite side surfaces 1b and 1c. The present invention is characterized in that a plurality of water absorbing yarns are embedded in the rib portion. In this example, a plurality of water absorbing yarns 2 are embedded in the rib portion 1a at equal intervals along the belt longitudinal direction. It is done. As shown in FIG. 2, this water-absorbent yarn 2 is opposed from one side surface 1b in the surface direction substantially perpendicular to the belt thickness direction (direction substantially parallel to the belt back surface) in each rib portion 1a. It extends in a direction inclined by about 45 ° with respect to the belt width direction toward the other side 1c. Further, since the water absorbing yarns 2 extend through in the belt width direction, both end portions of the water absorbing yarns 2 are exposed at the side surfaces 1b and 1c of the rib portion 1a. Furthermore, the water absorbing yarn 2 is embedded at a substantially central position (half of the height of the rib) of the rib in the belt thickness direction.

  In the present invention, since the water absorbing yarn is embedded in the rib portion embedded in such a state, water can be efficiently removed when running on water. That is, among the exposed ends on both sides of the water absorbing yarn embedded in an inclined manner in the rib portion of the compression rubber layer, the exposed end on the side advancing in advance and coming into contact with the pulley is the friction transmitting surface and the pulley Absorbs the intervening water. Then, the penetration of water is accelerated toward the other end of the water absorbing yarn by accelerating the penetration using the rotational force accompanying the traveling of the belt and the compression force of the compressed rubber layer by the side pressure from the pulley. , The compressed rubber layer is in a hydrated state. Thereafter, the water that has reached the end of the other (the side that contacts the pulley later) is discharged from the exposed end when it is not in contact with the pulley.

  Such a mechanism will be described in more detail using FIGS. 3 and 4. FIG. 3 is a schematic view showing the V-ribbed belt of the present invention mounted on a pulley, and FIG. 4 is a schematic view for explaining the flow of water in the rib portion. As shown in FIG. 3, in the state (B) where the friction transmission surface and the pulley start contact (A) and the friction transmission surface and the pulley are in contact (B), the water absorbing yarn comprises the friction transmission surface and the pulley To absorb the intervening water. More specifically, as shown in FIG. 4, the water absorbing yarn 2 is disposed between the friction transmission surface and the pulley from the exposed end 2a of the both exposed ends 2a and 2b which advance first and come into contact with the pulley. Absorb water that is present in

  Next, in a state (B) in which the friction transmission surface and the pulley are in contact with each other, water absorbed from the exposed end penetrates into the inside of the water absorbing yarn toward the other end, and the water compresses the rubber layer. Contained in water. In particular, while the penetration of water is accelerated by the rotational force accompanying the traveling of the belt, when the compressed rubber layer in contact with the pulley is compressed by the side pressure, the yarn is also compressed and the penetration is accelerated. Therefore, the synergetic effect combined with these accelerations promotes the penetration of water more. Furthermore, since the water absorbing yarn (water containing path) is disposed inclined at a predetermined angle with respect to the width direction of the belt, the water containing path can be made longer than when arranged in parallel with the width direction, so the compressed rubber layer It can contain much water inside.

  Furthermore, in the state (C) in which the friction transmission surface is not in contact with the pulley, the water that has permeated the water absorbing yarn can be discharged from the exposed end on the side in contact with the pulley later. More specifically, as shown in FIG. 4, the water absorbing yarn 2 penetrates from the exposed end 2a at the exposed end 2b that comes in contact with the pulley later than the exposed end 2a, and reaches the exposed end 2b. When the friction transmission surface is not in contact with the pulley (C), it can be discharged from the exposed end 2b.

(Compressed rubber layer)
In the surface direction substantially perpendicular to the belt thickness direction, the water absorbing yarn contained in the rib portion of the compression rubber layer is a direction inclined with respect to the belt width direction from one side surface of the rib portion to the opposite side surface facing the other side It is sufficient if the both ends of each water-absorbent yarn are exposed on each side, extending in the width direction and penetrating in the belt width direction.

  The water absorbing yarn may extend in a direction inclined with respect to the belt width direction in a surface direction substantially perpendicular to the back surface of the belt, but the angle with respect to the belt width direction is, for example, 5 ° or more (for example, 5 to 85 °) For example, it is about 10 to 83 °, preferably 20 to 80 °, and more preferably about 30 to 70 ° (particularly 40 to 60 °). The angle may be 30 ° or more (for example, 30 to 80 °), for example, 40 to 80 ° (for example, 40 to 70 °), preferably 45, because the power transmission performance at the time of water can be highly improved. It is about -75 degrees (for example, 45-60 degrees), More preferably, it is about 47-55 degrees (especially 48-52 degrees).

  If the water absorption inclination angle with respect to the belt width direction is too small, the balance between suction and discharge of water is lost, and the water existing between the friction transmission surface and the pulley can not be removed sufficiently. Transmission performance is reduced.

  The water-absorbent yarn may extend substantially in a direction substantially parallel to the back of the belt and penetrate the rib portion, and in the present specification and claims, “surface direction substantially perpendicular to the back of the belt” The surface direction is also included at an angle of, for example, 45 °, preferably 30 °, and more preferably 10 ° (particularly, 5 °) with respect to the surface direction substantially perpendicular to the belt back surface.

  Furthermore, the position of the water absorbing yarn penetrating the rib portion is not particularly limited as long as it can be embedded at a position capable of penetrating both side surfaces of the rib portion. From the viewpoint of improving the transmission performance and maintaining the durability of the belt, it is preferable to be embedded in a substantially central region in the belt thickness direction (the vertical direction of the back surface or the height direction of the rib portion). For example, it is preferable to include a water-absorbent yarn in the central region where the rib portion is divided into three equal parts (preferably five equal parts, more preferably seven equal parts) in the belt thickness direction. It is preferable to include the region within 10% of the total height of the rib portion from the center of the direction. If the position through which the water-absorbent yarn penetrates is positioned closer to the belt back surface (upper surface) than the substantially central area, the power transmission performance during running on water may decrease, and conversely, the inner circumference of the belt than the approximately central area If positioned on the surface (lower surface) side, the durability of the belt may be reduced. The water-absorbent yarn may be embedded at a plurality of heights in the substantially central region in order to improve the water discharge efficiency, and in addition to the substantially central region, other than the substantially central region (E.g., a region closer to the stretch layer than the substantially central region, or a region opposite to the stretch layer).

  The water absorbing yarn is exposed at both side surfaces of the rib portion by extending in the back direction at such an inclination angle with respect to the belt width direction. As a form of exposure, the end of the water absorbing yarn may be parallel to the side surface, or may protrude from the side surface to such an extent that the frictional engagement between the friction transmission surface and the pulley is not inhibited. Moreover, as long as water can contact the end of the water-absorbent yarn, it may be sunk from the side.

  The distance between the plurality of water absorbing yarns (the distance between adjacent water absorbing yarns in the belt length direction) can be selected from the range of about 1 to 15 mm (e.g. 1 to 10 mm), for example 3 to 15 mm (e.g. 3 to 10 mm), preferably Is preferably about 3.5 to 13 mm (e.g. 4 to 8 mm), more preferably 4 to 6 mm (especially 4.5 to 5.5 mm). If the distance is too small, the mechanical properties of the belt may be deteriorated to lower the durability. If the distance is too large, the water removal efficiency may be reduced.

  The water absorbing yarn may be a monofilament yarn, or may be a twisted cord in which a plurality of strands or multifilament yarns are twisted. Among these, a twisted cord obtained by twisting a plurality of multifilament yarns is preferable from the viewpoint of excellent water discharge efficiency. Furthermore, each of the fibers constituting the multifilament yarn may be a spun yarn (spun yarn) or a microfiber from the viewpoint of being able to improve the water absorption.

  The twisting method in the twist cord includes, for example, multiple twist, single twist, rung twist and the like. Among these, Lang-twist is preferable in terms of excellent water discharge efficiency. In Lang-twist, the number of twists of the upper twist is, for example, 3 to 100 times / 10 cm, preferably 7 to 60 times / 10 cm, and more preferably 10 to 40 times / 10 cm from the viewpoint of excellent water discharge efficiency. is there. The number of twists of the first twist is, for example, 2 to 100 times / 10 cm, preferably 5 to 50 times / 10 cm, and more preferably about 10 to 35 times / 10 cm, from the viewpoint of excellent water discharge efficiency.

  The average fiber diameter of the water-absorbent yarn is, for example, 0.05 to 1.5 mm (for example, 0.1 to 1 mm), preferably 0.2 to 0.8 mm (for example, 0.2 to 0.4 mm), and more preferably 0. About 0.3 to 0.5 mm (e.g., 0.25 to 0.35 mm). Furthermore, the average fiber diameter of the water-absorbent yarn is, for example, 0.1 to 0.8 mm, preferably 0.3 to 0.7 mm, from the viewpoint of achieving both the durability of the belt and the power transmission performance when running on water. More preferably, it is about 0.4 to 0.6 mm. If the average fiber diameter is too small, the water removal efficiency may be reduced. If it is too large, the mechanical properties of the belt may be reduced and the durability may be reduced. There is a risk that it will clog.

  In multifilament yarns, the average fiber diameter of single fibers can be selected from the range of about 1 to 100 μm (for example, 3 to 50 μm), but 50 μm for highly water-absorbent fibers such as cellulosic fibers from the viewpoint of water discharge efficiency. Or less, for example, about 3 to 50 μm, preferably about 5 to 40 μm, and more preferably about 10 to 30 μm, and for fibers having relatively low water absorbability such as polyester fiber and polyamide fiber, 10 μm or less (particularly 8 μm) Or less, and may be, for example, about 1 to 10 μm, preferably about 2 to 8 μm, and more preferably about 3 to 7 μm (particularly about 4 to 6 μm). When the fiber diameter of the single fiber decreases, capillary phenomenon occurs and the surface area of the fiber also increases, so the water absorbency of the water-absorbent yarn can be improved.

  The shape of the water-absorbent yarn (in the case of a multifilament yarn, a single fiber) is not particularly limited, and the cross-sectional shape (cross-sectional shape perpendicular to the longitudinal direction of the fiber) is, for example, substantially circular, oval, flat It may be polygonal (triangular, hexagonal, etc.), multilobal or star (eg, 3 to 6 lobes), dog bone, T-shaped, V-shaped, indeterminate, hollow, etc. Among these shapes, fibers with high water absorbency such as cellulosic fibers may be substantially circular or elliptical, but from the viewpoint of being able to improve the water absorbency of the water-absorbent yarn, they have a generally general shape. Shapes other than circular (round cross section), for example, polygonal shape, multilobal or star shape, irregular shape etc. are preferable.

  The water-absorbent yarn may be a so-called deformed cross-sectional yarn (a yarn whose cross section is a polygonal shape, multi-leaf or star shape, irregular shape, etc.) or a hollow yarn. The modified cross-section yarn may be a yarn having a plurality of (for example, 2 to 10, preferably about 3 to 6) recesses or grooves extending in the longitudinal direction, as viewed from the center of the cross section, The yarn may have a shape having a plurality of recesses at symmetrical positions. Water absorbing yarns having these cross-sectional shapes can be obtained by adjusting the nozzle shape at the time of spinning.

The type of the water-absorbent fiber constituting the water-absorbent yarn is not particularly limited as long as it has hydrophilicity and can absorb water during the running process of the belt, for example, vinyl alcohol fibers (eg polyvinyl alcohol, ethylene-vinyl alcohol) C fibers such as copolymer fibers, vinylon, etc., polyamide fibers (polyamide 6 fibers, polyamide 66 fibers, polyamide 46 fibers, aramid fibers, etc.), polyester fibers [polyethylene terephthalate (PET) fibers, polyethylene naphthalate (PEN) fibers, etc. _2-4 alkylene C _8-14 arylate fibers and the like], cellulose fibers [eg, cellulose fibers (cellulose fibers derived from plants, animals, bacteria, etc.), fibers of cellulose derivatives, etc.] can be exemplified. Cellulose fibers include, for example, wood pulp (softwood, hardwood pulp etc.), bamboo fibers, sugar cane fibers, seed hair fibers [eg cotton fibers (cotton linters), kapok etc.], gin peel fibers (eg hemp, kozo, Cellulose fibers (pulp fibers) derived from natural plants such as Mitsumata etc., leaf fibers (eg manila hemp, New Zealand hemp etc.) Cellulose fibers of animal origin such as wool, silk, ascidian cellulose, bacterial cellulose fibers, algal cellulose etc. It can be illustrated. As a fiber of a cellulose derivative, cellulose ester fiber; regenerated cellulose fiber (rayon etc.) etc. are mentioned, for example. These water-absorbent fibers can be used alone or in combination of two or more.

  Among them, preferred are vinyl alcohol fibers and cellulose fibers from the viewpoint of water absorbability, and polyamide fibers (for example, meta fibers) from the point of being excellent in the balance between water absorbency and handleability by adjusting the fiber diameter and shape. Aramid fibers and the like) and polyester fibers (for example, PET fibers and the like) are preferred. In particular, cellulose fibers such as cellulose fibers are particularly preferable because they are excellent in various properties including water absorbency. Furthermore, by preparing a multifilamentary yarn using the water-absorbent fiber as a microfiber, a water-absorbent yarn excellent in not only water-absorbent property but also balance of various properties such as drainage is obtained. It may be formed of at least one selected from the group consisting of polyesters. The microfiber is an ultrafine fiber with a fiber diameter of 8 μm or less, and the fiber cross section also has an acute angle or a polygonal shape, so it has a strong water absorbency and expresses a water absorbency greater than cellulose fibers such as cotton. In addition, it has excellent drainage performance, and it has the property of being able to be dried easily only by squeezing it even when it is in a state of sucking in water, so that water between the pulley and the friction surface can be effectively removed.

  The water absorbing yarn may be subjected to various adhesion treatments with an epoxy compound, an isocyanate compound or the like in order to improve the adhesion to the rubber composition constituting the compressed rubber layer, but water passes through the water absorbing yarn. It is particularly preferable not to carry out the adhesion treatment in terms of expanding the route and improving the water absorption.

  The compression rubber layer is formed of a conventional vulcanized rubber composition for forming a compression rubber layer of a V-ribbed belt except that the rib portion contains a water absorbing yarn.

  The vulcanized rubber composition comprises a polymer component. As the polymer component, known rubber components and / or elastomers, for example, diene rubber (natural rubber, isoprene rubber, butadiene rubber, chloroprene rubber, styrene butadiene rubber (SBR), acrylonitrile butadiene rubber (nitrile rubber), hydrogenated nitrile Rubber (including mixed polymer of hydrogenated nitrile rubber and metal salt of unsaturated carboxylic acid), ethylene-α-olefin elastomer, chlorosulfonated polyethylene rubber, alkylated chlorosulfonated polyethylene rubber, epichlorohydrin rubber, acrylic rubber , Silicone rubber, urethane rubber, fluorine rubber and the like. These polymer components can be used alone or in combination. Among these polymer components, from the viewpoint of containing no harmful halogen, having ozone resistance, heat resistance, cold resistance and being excellent in economy, ethylene-α-olefin elastomer [ethylene-propylene copolymer (EPM And ethylene-α-olefin rubber such as ethylene-propylene-diene terpolymer (EPDM). The content of the polymer component in the vulcanized rubber composition may be, for example, about 40 to 65% by mass (for example, 42 to 60% by mass), preferably about 45 to 55% by mass (for example, 47 to 53% by mass) .

  The vulcanized rubber composition may, if necessary, contain known additives or additives. As the additive, for example, a vulcanizing agent or a crosslinking agent [eg, oximes (eg, quinone dioxime), guanidines (eg, diphenyl guanidine), metal oxides (eg, magnesium oxide, zinc oxide), organic peroxides (eg, Diacyl peroxides, peroxy esters, dialkyl peroxides etc.], vulcanization assistants, vulcanization accelerators, vulcanization retarders, reinforcing agents (carbon black, silicon oxides such as hydrous silica etc.), metal oxides For example, calcium oxide, barium oxide, iron oxide, copper oxide, titanium oxide, aluminum oxide etc., fillers (clay, calcium carbonate, talc, mica etc.), short fibers (water-absorbent fibers, etc.) Short fibers made of fiber), plasticizers, softeners (oils such as paraffin oil and naphthenic oil), Engineering agents or processing aids (stearic acid, metal salts of stearic acid, waxes, paraffin, etc.), anti-aging agents (aromatic amines, benzimidazole anti-aging agents, etc.), adhesion improver [resorcin-formaldehyde co-condensate , Melamine resins such as hexamethoxymethylmelamine, co-condensates of these (such as resorcin-melamine-formaldehyde co-condensate), colorants, tackifiers, coupling agents (such as silane coupling agents), stabilizers (such as silane coupling agents) Antioxidants, UV absorbers, heat stabilizers, etc.), lubricants, flame retardants, antistatic agents, etc. can be exemplified. These additives may be used alone or in combination, and may be appropriately selected and used according to the type, use, and performance of the polymer component.

  The proportion of the additive can also be appropriately selected according to the type of the polymer component and the like. For example, the proportion of the reinforcing agent (carbon black etc.) is 10 parts by mass or more (eg 20 to 150 parts by mass), preferably 20 parts by mass or more (eg 25 to 120 parts by mass) with respect to 100 parts by mass of the polymer component More preferably, it may be 30 parts by mass or more (for example, 35 to 100 parts by mass), particularly 40 parts by mass or more (for example, 50 to 80 parts by mass).

  The average thickness of the compression rubber layer is, for example, about 2 to 25 mm, preferably about 2.2 to 16 mm, and more preferably about 2.5 to 12 mm.

(Core)
The core body is not particularly limited, but usually, core wires (twisted cords) arranged at predetermined intervals in the belt width direction can be used.

  As the core wire, high modulus fibers, for example, the above-mentioned polyester fibers (polyalkylene arylate fibers), synthetic fibers such as aramid fibers, inorganic fibers such as carbon fibers, etc. are widely used, and polyester fibers (polyethylene terephthalate fibers, ethylene na Phthalate fibers) and aramid fibers are preferred. The fibers may be multifilament yarns, for example multifilament yarns having a denier of about 2000 to 10000 denier (especially 4000 to 8000 denier).

  As the core wire, a twist cord (for example, multi-twist, single twist, rung twist, etc.) using multifilament yarn can be usually used. The average wire diameter of the core wire (fiber diameter of the twisted cord) may be, for example, about 0.5 to 3 mm, preferably about 0.6 to 2 mm, and more preferably about 0.7 to 1.5 mm. The core lines may be embedded in the longitudinal direction of the belt, and one or more core lines may be embedded in parallel at a predetermined pitch in parallel to the longitudinal direction of the belt.

  In order to improve the adhesion to the polymer component, the core wire may be subjected to various adhesion treatments such as epoxy compound and isocyanate compound. As the adhesion treatment, a method of immersing a heat-resistant fiber in a resin-based treatment solution in which an epoxy or isocyanate compound is dissolved in an organic solvent (toluene, xylene, methyl ethyl ketone etc.), resorcin-formalin-latex solution (RFL solution) The method of immersing in a process liquid etc. are mentioned.

(Stretch layer)
The stretch layer may be formed of the same vulcanized rubber composition as the compressed rubber layer, or may be formed of a fabric (reinforcing cloth) such as canvas. The stretch layer may also be a combination of a rubber composition and a fabric.

  Examples of the cloth (reinforcement cloth) include cloth materials such as woven cloth, wide angle canvas, knitted cloth, and nonwoven cloth. Among these, preferred are woven fabrics woven in the form of plain weave, twill weave, satin weave, etc., and wide-angle canvas or knitted fabric having a crossing angle of about 90 to 120 ° between warp and weft. As fibers constituting the reinforcing cloth, the fibers (water-absorbent fibers, non-water-absorbent fibers, etc.) exemplified in the section of the fiber member can be used.

  In addition, the reinforcing cloth may be subjected to adhesion treatment [for example, adhesion treatment such as immersion treatment in resorcin-formalin-latex solution (RFL solution)]. Further, after the adhesion treatment, the rubber composition may be rubbed or coated (coated) to form a rubberized canvas.

  Furthermore, an uneven pattern may be provided on the surface of the stretch layer (the back surface of the belt). Examples of the concavo-convex pattern include a knitted fabric pattern, a woven fabric pattern, a stray fabric pattern, and an embossed pattern. Among these patterns, a woven pattern and an embossed pattern are preferred.

  The average thickness of the stretching layer may be, for example, about 0.5 to 10 mm, preferably about 0.7 to 8 mm, and more preferably about 1 to 5 mm.

(Adhesive layer)
The adhesive layer is not necessarily required as described above. The adhesive layer (adhesive rubber layer) can be made of, for example, a vulcanized rubber composition (a vulcanized rubber composition containing a rubber component such as ethylene-α-olefin elastomer) similar to the above-mentioned compressed rubber layer. The vulcanized rubber composition of the adhesive layer may further contain an adhesion improver (resorcin-formaldehyde co-condensate, amino resin, etc.).

  The thickness of the adhesive layer can be appropriately selected according to the type of belt and the like, but may be, for example, about 0.2 to 5 mm, preferably 0.3 to 3 mm, and more preferably about 0.5 to 2 mm.

  In the rubber composition of the stretch layer and the adhesive layer, a polymer component of the same type or the same type as the polymer component of the rubber composition of the compressed rubber layer is often used as the polymer component. Further, in these rubber compositions, the proportions of additives such as a vulcanizing agent, a crosslinking agent, a co-crosslinking agent or a crosslinking assistant, and a vulcanization accelerator are the same as in the vulcanized rubber composition of the compressed rubber layer, respectively. You can choose from the range of

[Method of manufacturing V-ribbed belt]
The V-ribbed belt of the present invention comprises a cylindrical drum, a sheet for forming a stretch layer (sheet for stretch layer), a core, and a sheet for forming a compressed rubber layer (sheet for compressed rubber layer) It is manufactured through a winding step of sequentially winding, and a vulcanization forming step of vulcanizing and forming the unvulcanized rubber sheet by pressing the wound laminated sheet against a mold.

  In the present invention, conventional methods can be used other than the method of winding the sheet for compressed rubber layer. As a method for winding the compressed rubber layer sheet, for example, a first unvulcanized rubber sheet (first compressed rubber layer sheet) for forming a compressed rubber layer and a second for forming a compressed rubber layer Between the unvulcanized rubber sheet (the second compressed rubber layer sheet) and the laminated sheet having the water absorbing yarn temporarily fixed at a predetermined angle with respect to the length direction of the sheet. A method according to 1, wherein a first compression rubber layer sheet having a water absorbing yarn temporarily fixed at intervals at a predetermined angle with respect to a sheet length direction and a second compression rubber layer sheet are sequentially wound. A method of 2, the first compression rubber layer sheet and a second compression rubber layer sheet on which a water absorbing yarn is temporarily fixed at a predetermined angle with respect to the longitudinal direction of the sheet. Method 3 and the like can be mentioned.

  In the first method, the belt thickness direction is obtained by winding and vulcanizing a laminated sheet in which the first compressed rubber layer sheet, the water absorbing yarn, and the second compressed rubber layer sheet are temporarily fixed and integrated. The water absorbing yarn can be embedded in the compression rubber layer in a state of extending in a surface direction substantially perpendicular to the On the other hand, in the second method, the first compressed rubber layer sheet is wound such that the water absorbing yarn is disposed on the outer peripheral side, and the first compressed rubber layer sheet and the second compressed rubber layer sheet By disposing the water absorbing yarn at the boundary of the water absorbing yarn, the water absorbing yarn can be embedded in the compression rubber layer in a state of extending in a surface direction substantially perpendicular to the belt thickness direction. In the third method, the second compressed rubber layer sheet is wound so that the water absorbing yarn is disposed on the inner peripheral side, and the first compressed rubber layer sheet and the second compressed rubber layer sheet are wounded. The water absorbing yarn can be embedded in the compression rubber layer in a state of being extended in the belt back direction by arranging the water absorbing yarn at the boundary between the two. In the first method, at the boundary between the first compressed rubber layer sheet, the water absorbing yarn, and the second compressed rubber layer sheet, in the second and third methods, the first compressed rubber layer sheet or In the second compressed rubber layer, the water absorbing yarns can be placed on the sheet and temporarily fixed according to the desired spacing and angle. In addition, by adjusting the thickness ratio between the first compression rubber layer sheet and the second compression rubber layer sheet, the position at which the water absorbing yarn is embedded can be adjusted. The thickness is adjusted, and the water absorbing yarn is embedded in the central region of the rib portion. Furthermore, when the water absorbing yarn is embedded at a plurality of heights of the rib portion, the compression rubber layer sheet and the water absorbing yarn are interposed between the first compression rubber layer sheet and the second compression rubber layer sheet. It may be interposed by the same method to form a laminated structure of three or more layers.

  In temporary fixing, it may be heat-pressed at a temperature lower than the heating temperature in the subsequent vulcanization step to prepare a semi-vulcanized state. Although heating temperature can be selected according to the kind of rubber | gum, in the case of an ethylene-alpha-olefin elastomer, it is 60-100 degreeC, for example, Preferably 70-90 degreeC, More preferably, it is about 75-85 degreeC. The pressure is, for example, about 0.1 to 5 MPa, preferably about 0.3 to 3 MPa, and more preferably about 0.5 to 2 MPa.

  When the V-ribbed belt has an adhesive layer, generally, after winding the core, an adhesive layer sheet (unvulcanized rubber sheet) may be wound. For example, the following method may be used to manufacture a belt through a winding step and a vulcanization forming step.

(First manufacturing method)
First, the stretch layer sheet is wound around a cylindrical mold having a smooth surface, and a core wire (such as a treated rope) is helically spun on the sheet, and further, an adhesive layer sheet, first and second The compressed rubber layer sheet is wound sequentially to prepare a molded body. Thereafter, a vulcanizing jacket is placed over the molded body, and the mold (mold) is accommodated in the vulcanizer, and after vulcanization under predetermined vulcanization conditions, the mold is removed from the mold and cylindrical Obtain a vulcanized rubber sleeve. Then, after the outer surface (compression layer) of the vulcanized rubber sleeve is polished by a grinding wheel to form a plurality of ribs, the vulcanized rubber sleeve is cut to a predetermined width in the longitudinal direction of the belt using a cutter. Finished with V-ribbed belt. In addition, the V-ribbed belt provided with the compression layer which has a rib part in an internal peripheral surface is obtained by reversing the cut belt.

(Second manufacturing method)
First, use a cylindrical inner mold with a flexible jacket attached to the outer peripheral surface as the inner mold, wrap the unvulcanized stretch layer sheet around the flexible jacket on the outer peripheral surface, and spiral the core wire on this sheet The sheet is spun and the first and second compressed rubber layer sheets are wound to produce a laminate. Next, as an outer mold that can be attached to the inner mold, a cylindrical outer mold in which a plurality of rib molds are engraved on the inner circumferential surface is used, and the inner mold in which the laminate is wound is housed in the outer mold. , Installed concentrically. Thereafter, the flexible jacket is expanded toward the inner peripheral surface (rib type) of the outer mold, and the laminate (compressed layer) is pressed into the rib type and vulcanized. Then, after removing the inner mold from the outer mold and removing the vulcanized rubber sleeve having a plurality of ribs from the outer mold, the vulcanized rubber sleeve is cut to a predetermined width in the longitudinal direction of the belt using a cutter, The water absorbing yarn is exposed by polishing the side surface of the rib portion to finish it as a V-ribbed belt. In this second manufacturing method, the laminate provided with the stretch layer, the core wire and the compressed rubber layer can be expanded at one time to form a sleeve (or V-ribbed belt) having a plurality of ribs.

(Third manufacturing method)
In relation to the second production method, for example, the method disclosed in JP-A-2004-82702 (only the first and second compressed rubber layers are expanded to form a preform (semi-vulcanized state), Then, a method may be employed in which the stretch layer and the core wire are expanded to be crimped to the preform, and then vulcanized and integrated into a V-ribbed belt.

  The present invention will be described in more detail based on examples given below, but the present invention is not limited by these examples. In the following examples, the measurement method or evaluation method for each physical property, and the compositions of the raw materials and rubber compositions used in the examples are shown below.

(material)
EPDM: Mitsui Chemical Co., Ltd. “EPT2060M”
Cotton short fiber: Denim (average fiber diameter 13 μm, average fiber length 6 mm)
Nylon staple fiber: 66 nylon (average fiber diameter 27 μm, average fiber length 3 mm)
Anti-aging agent: Ouchi Shinko Chemical Co., Ltd. "Nocrac MB"
Vulcanizing agent: "Barnock DMG" manufactured by Ouchi Emerging Chemical Industry Co., Ltd.
Carbon black HAF: “Siest 3” manufactured by Tokai Carbon Co., Ltd.
Carbon black GPF: Toast Carbon Co., Ltd. "Seat V"
Organic peroxide: "Parkmill D-40" manufactured by NOF Corporation
Zinc oxide: "Zinc oxide three types" manufactured by Shodo Chemical Industry Co., Ltd.
Absorbent thread: Cotton sewing thread, Fujibo Co., Ltd. "Hinode Katan", thread diameter 0.1 to 1 mm
Fluorine fiber: Teflon (registered trademark) thread, Toray Industries, Inc. "Toyoflon", fiber diameter 0.3 mm
Core wire: Aramid fiber twist cord, manufactured by Teijin Limited "Twaron", core diameter 0.73 mm.

(Rubber composition for compressed rubber layer, elastic layer and adhesive layer)
The rubber compositions for the compressed rubber layer, the elastic layer and the adhesive layer used in the examples and comparative examples are shown in Table 1.

Example 1
The rubber composition A shown in Table 1 was used for the stretch layer sheet and the adhesive layer sheet, and the rubber composition B shown in Table 1 was used for the compressed rubber layer sheet. These rubber compositions were kneaded, and the kneaded rubber was rolled through a calender roll to a predetermined thickness to produce each rubber sheet. In addition, about the sheet | seat for compression rubber layers, it manufactured with half thickness of predetermined thickness so that the embedding position of a water absorbing yarn may be located in the center part (rib center part) of a rib part.

  Next, a second compression rubber layer is disposed on the first compression rubber layer sheet at intervals of 5 mm at an angle of 50 ° with respect to the belt width direction so as to sandwich the water absorption yarn. I stacked the sheet for. And the sheet | seat for compression rubber layers which temporarily fixed the water absorbing yarn between two sheets was produced with the heat press (80 degreeC, 1 Mpa, 30 seconds).

  Furthermore, a V-ribbed belt was manufactured using the following known method. First, the stretch layer sheet is wound around the outer periphery of a cylindrical molding mold having a smooth surface, and the core wire forming the core is spirally spun around the outer periphery of the stretch layer sheet, and further, an adhesive layer sheet, A sheet for compression rubber layer with the water absorbing yarn temporarily fixed was wound sequentially to form a formed body. Thereafter, the molding mold is placed in a vulcanizing can with the vulcanizing jacket covered on the outer periphery of the molding, and after vulcanization at a temperature of 160 ° C. for 30 minutes, the mold is removed from the molding mold A tubular belt sleeve was obtained.

  The outer surface (compressed rubber layer) of the belt sleeve is ground at predetermined intervals by a grinding wheel to form a plurality of ribs in which the end of the water absorbing yarn is exposed from the friction transmission surface, and then a belt sleeve is used to cut the belt sleeve. Is cut by a predetermined width in the longitudinal direction of the belt, and the number of ribs in the width direction is 3, V-ribbed belt with a circumferential length of 1100 mm (belt type: PK type, belt thickness: 4.3 mm, rib height: 2 mm, rib pitch : 3.56 mm) was obtained.

Comparative Example 1
A rubber composition comprising a sheet for compression rubber layer containing water-absorbent cotton short fibers instead of the sheet for compression rubber layer in which the water absorbing yarn is temporarily fixed between the first and second sheets for compression rubber layer (Table 1 A V-ribbed belt having 3 ribs in the width direction and a circumferential length of 1100 mm was produced by the method according to Example 1 except that it was made into one sheet using the rubber composition C).

Comparative example 2
The width is the same as in Example 1, except that the water absorbing yarns temporarily fixed between the first and second compressed rubber layer sheets are arranged in parallel (no angle) to the belt width direction. A V-ribbed belt having three ribs in the direction and a circumferential length of 1100 mm was produced.

Comparative example 3
As a yarn to be temporarily fixed between the first and second compressed rubber layer sheets, the width direction is the same as in Example 1, except that a fluorine fiber having no water absorbing ability is used instead of the water absorbing yarn. A V-ribbed belt having three ribs and a circumferential length of 1100 mm was produced.

Comparative example 4
The rubber composition B is used, and the number of ribs in the width direction is three, the circumferential length by the method according to Example 1 except that one sheet not containing a water absorbing yarn is used as a sheet for compressed rubber layer Made a V-ribbed belt of 1,100 mm. V is provided with a plurality of water drainage holes by opening through holes of 5 mm intervals at an angle of 50 ° (in the same manner as the path of the water absorbing yarn of Example 1) using a cone in the compression layer of this belt I got a ribbed belt.

Comparative example 5
In the same manner as in Comparative Example 4, a V-ribbed belt having three ribs in the width direction and a circumferential length of 1100 mm was produced. In each rib groove of this belt, in order to form a structure according to FIG. 5 of Patent Document 6, a through hole is formed at intervals of 5 mm in the longitudinal direction of the belt from the bottom of the groove toward the back surface of the belt. And a V-ribbed belt having a plurality of drainage holes.

  Using the V-ribbed belts of Example 1 and Comparative Examples 1 to 5, the water injection transfer performance test and the endurance running test were performed by the following method.

(Water injection transfer performance test)
In the test, under the test conditions shown in Table 2, in the layout shown in FIG. 5, a V-ribbed belt is hung on each pulley, and a tension of 150 N or 180 N is applied to one belt to drive a drive pulley (Dr.) It was rotated at 1000 rpm. Then, load is gradually applied to the driven pulley (Dn.), Water injection is performed at 300 ml / min (from the vicinity of the arrow shown in FIG. 5), and the transmission torque is measured when the slip ratio of the belt reaches 2%. did. As the value of the transmission torque is larger, it is difficult to slip and the transmission performance is excellent.

  Table 3 shows transmission torque values at 2% slip in the belts of Example 1 and Comparative Examples 1 to 5. In Table 2, the transmission torque value in Comparative Example 1 under the condition 1 (tension 150 N / belt) is “1”, and the transmission torque values under other conditions are shown as relative values.

(Durability running test)
As shown in FIG. 6, a test machine in which a drive pulley (Dr) having a diameter of 120 mm, an idler pulley (ID) having a diameter of 85 mm, a driven pulley (Dn) having a diameter of 120 mm, and a tension pulley (Ten) having a diameter of 45 mm It was. That is, a V-ribbed belt is hung around each pulley of this tester, the rotation speed of the drive pulley is 4900 rpm, the belt winding angle on the idler pulley and the tension pulley is 120 ° and 90 °, and the driven pulley load is 8.8 kW A shaft load of 559 N was applied, and the belt was continuously run for 200 hours in the clockwise direction at an atmosphere temperature of 120 ° C. Tables 3 to 7 show the results of evaluation as to whether or not the vehicle could run for 200 hours without cracking in the endurance running test.

  As is clear from the results in Table 3, in the water injection transfer performance test, the transfer torque value at 2% slip under condition 1 is 1.05 in Example 1 with respect to Comparative Example 1 (1.00). Although improved, Comparative Example 2 decreased to 0.96, Comparative Example 3 to 0.89, Comparative Example 4 to 0.91, and Comparative Example 5 to 0.93.

  Similarly, the condition 2 was improved in Example 1, but decreased in Comparative Examples 1 to 5. Therefore, it can be said that the V-ribbed belt of Example 1 improves the transmission performance by efficiently absorbing (water-retaining) and draining water present between the friction transmission surface and the pulley when traveling in water.

  On the other hand, also in the endurance running test, in Example 1, the continuous running was completed without any problems for 200 hours, while in Comparative Example 2 in which the disposition angle of the water absorbing yarn was 0 ° and in Comparative Example 4 in which only the through holes were formed. A crack (crack) was generated in the rib portion and the life was 183 hours or 180 hours.

Examples 2 to 4
A V-ribbed belt is manufactured in the same manner as in Example 1 except that the arrangement angle of the water absorbing yarn with respect to the belt width direction is changed from 50 ° to 10 °, 30 ° or 80 °, and the water transfer performance test and endurance running test are performed. The provided results are shown in Table 4. The results of Example 1 are also shown.

  As is clear from the results in Table 4, in the water transfer performance test, Example 1 (50 °) and Example 2 (10 °), Example 3 (30 °), and Example 4 (80 °) Similarly, the transfer torque value at 2% slip was improved relative to Comparative Example 1. Also, in the endurance running test, in all cases, continuous running for 200 hours was completed without any problems.

Examples 5 to 7
A V-ribbed belt was produced in the same manner as in Example 1 except that the arrangement interval of the water-absorbent yarn was changed from 5 mm to 3 mm, 10 mm or 13 mm. Table 5 shows the results of water injection transmission performance test and endurance running test. . The results of Example 1 are also shown.

  As is clear from the results of Table 5, in the water injection transmission performance test, also in Example 5 (3 mm), Example 6 (10 mm), and Example 7 (13 mm), as in Example 1 (5 mm), 2 The transmission torque value at% slip was improved relative to Comparative Example 1. In the endurance running test, while running continuously for 200 hours without problems in Examples 1, 6 and 7, in Example 5 where the arrangement interval is small, the rib portion (especially, around the water absorbing yarn) is cracked ( The crack occurred and the life was reached in 189 hours. In Example 5 where the arrangement interval is small, the amount of embedded water absorbing yarn (volume ratio in occupying the rib portion) is large, so the water absorption performance (water injection transmission performance) is most excellent, while the rubber portion occupying the rib portion Since the volumetric ratio is reduced, the rigidity of the rib portion is reduced, so that it can be estimated that the durability is reduced in terms of the side pressure resistance. Furthermore, when the belt is bent and deformed while being wound around the pulley during traveling, deformation stress is concentrated at the interface between the high-rigidity rubber portion and the low-rigidity water absorbing yarn, and a crack (crack) is easily generated. However, it can be estimated that the durability decreased.

Examples 8 to 10
A V-ribbed belt is manufactured in the same manner as in Example 1 except that the average fiber diameter of the water-absorbent yarn is changed from 0.3 mm to 0.1 mm, 0.5 mm or 1 mm, and used for water injection transmission performance test and endurance running test. The results are shown in Table 6. The results of Example 1 are also shown.

  As apparent from the results in Table 6, in the water injection transfer performance test, the fiber diameter increases in the order of Example 8 (0.1 mm), Example 1 (0.3 mm), and Example 9 (0.5 mm). The water transfer performance was improved in order), but in Example 10 (1 mm), it was slightly lower than in Example 9 (0.5 mm).

  In the endurance running test, while running continuously for 200 hours without problems in Examples 1 and 8 to 9, the running was continuously run for 200 hours, whereas in Example 10 with a large fiber diameter, the rib (especially around the water absorbing yarn) was cracked ( The crack occurred and the life became 185 hours.

  From these results, as the average fiber diameter of the water-absorbent yarn is larger, the water absorption performance is improved and the slip is suppressed, but the volumetric proportion of the rubber portion occupying the rib portion decreases and the contact surface with the pulley It can be estimated that slippage becomes easy as the area of the portion of the rubber in contact with the pulley is reduced. That is, until the average fiber diameter is about 0.5 mm (Example 9), the slip is suppressed by the effect of the improvement of the water absorption performance, and the water injection transmission performance (the transmission torque value at 2% slip) is improved. Even if the fiber diameter becomes larger, the slip suppression effect due to water absorption is slightly offset by the slip due to the lack of the contact area of the rubber part, so the water injection transmission performance (transmission torque value at 2% slip) is more than that It can be estimated that it did not improve.

Examples 11 to 12
A V-ribbed belt is manufactured in the same manner as in Example 1 except that the embedding position of the water-absorbent yarn is changed from the rib central portion to the rib upper portion (rear side from the central portion) or the rib lower portion (inner peripheral surface side from the central portion) Table 7 shows the results of the water injection transfer performance test and the endurance running test. The results of Example 1 are also shown. In addition, the embedding position of the water absorbing yarn adjusts the thickness ratio of the sheet for compressed rubber layer, and the rib upper part (upper part of the rib part) is embedded from the back to a depth of about 1/4 of the thickness of the rib part The lower portion (lower portion of the rib portion) was embedded from the inner peripheral surface to a depth of about 1/4 of the thickness of the rib portion.

  As is clear from the results of Table 7, in Example 11 in which the water absorbing yarn was embedded in the upper portion of the rib, the continuous running was completed without failure for 200 hours in the endurance running test, but in the water injection transmission performance test, the water absorbing yarn was Although some improvement was seen with respect to the comparative example 1 which does not embed | bury, the improvement as Example 1 which embedded the water absorbing yarn in the rib center part was not seen. On the other hand, in Example 12 in which the water absorbing yarn was embedded in the lower part of the rib, in the water injection transmission performance test, the same transmission performance improvement as in Example 1 was observed. Was a lifetime of 197 hours.

  The V-ribbed belt of the present invention is useful as a V-ribbed belt used for driving auxiliary equipment of automobile engines such as air compressors and alternators.

DESCRIPTION OF SYMBOLS 1 ... Compression rubber layer 1a ... Rib part 2 ... Water absorbing yarn 3 ... Adhesive layer 4 ... Core wire 5 ... Stretch layer

Claims (9)

A stretch layer that forms the back of the belt,
A compressed rubber layer having a plurality of ribs formed on one surface of the stretch layer and aligned in the belt width direction;
A V-ribbed belt comprising a core embedded between the stretch layer and the compressed rubber layer,
The rib portion includes a plurality of water absorbing yarns frictionally engaged in contact with the pulley on two opposite side surfaces and embedded at intervals in the longitudinal direction of the belt;
Each water absorbing yarn extends in a direction inclined with respect to the belt width direction from the one side surface of the rib portion to the opposite side surface in the surface direction substantially perpendicular to the belt thickness direction, and in the belt width direction The V-ribbed belt which penetrates and which the both ends of each water absorbing yarn are exposed on each side of a rib part.   The V-ribbed belt according to claim 1, wherein a distance between the plurality of water absorbing yarns is 2 to 15 mm.   The V-ribbed belt according to claim 1 or 2, wherein a water absorbing yarn is contained in the central region of the rib portion in the belt thickness direction.   The V-ribbed belt according to any one of claims 1 to 3, wherein the angle of the water absorbing yarn with respect to the belt width direction is 5 to 85 °.   The V-ribbed belt according to any one of claims 1 to 4, wherein the average fiber diameter of the water-absorbent yarn is 0.1 to 1 mm.   The V-ribbed belt according to any one of claims 1 to 5, wherein the water-absorbent yarn is a multifilament yarn having an average fiber diameter of 8 μm or less of a single fiber.   The V-ribbed belt according to any one of claims 1 to 6, wherein the water-absorbent yarn is at least one selected from the group consisting of cellulosic fibers, polyamide fibers and polyester fibers.   A winding step of sequentially winding a sheet for forming a stretch layer, a core, and a sheet for forming a compressed rubber layer on a cylindrical drum, pressing the wound laminated sheet against a mold to carry out the non-addition The method for producing a V-ribbed belt according to any one of claims 1 to 7, further comprising a vulcanization forming step of vulcanizing and forming a vulcanized rubber sheet.   A method of winding a sheet for forming a compressed rubber layer is between a first unvulcanized rubber sheet for forming a compressed rubber layer and a second unvulcanized rubber sheet for forming a compressed rubber layer. A method of winding a laminated sheet having a water absorbing yarn temporarily fixed at a predetermined angle with respect to the longitudinal direction of the sheet, and absorbing water at a predetermined angle with respect to the longitudinal direction of the sheet A method of sequentially winding a first unvulcanized rubber sheet for forming a compressed rubber layer on which a yarn is temporarily fixed and a second unvulcanized rubber sheet for forming a compressed rubber layer, or a first compression The method according to claim 8, wherein the method is a method of sequentially winding a rubber layer sheet and a second compressed rubber layer sheet having water absorbing yarns temporarily fixed at intervals at a predetermined angle with respect to the sheet length direction. Method.