JP2019132430A - Friction transmission belt and method for manufacturing the same - Google Patents

Abstract

To improve strength of a junction of a knitted fabric (reinforcement fabric) for covering a friction transmission surface of a friction transmission belt.SOLUTION: In a V-ribbed belt 1, a surface of a rib part 2 to be a friction transmission surface is covered by a knitted fabric 6 having a junction 60 sutured by a sewing thread 61.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a friction transmission belt having a friction transmission surface covered with a knitted fabric and a method for manufacturing the same.

  Frictional power transmission belts are widely used for driving automobile auxiliary machinery and agricultural machinery. Examples of the friction transmission belt include a flat belt, a V belt, a V-ribbed belt, and the like, and a meshing transmission belt including a toothed belt that transmits power by mechanically fitting the tooth portion of the pulley and the tooth portion of the belt. It is used in distinction. Among them, the V-ribbed belt is widely used for driving an auxiliary machine of an automobile because it can achieve both high transmission capacity and bending fatigue resistance.

  Some V-ribbed belts have a friction transmission surface covered with a reinforcing cloth in order to improve wear resistance or adjust a friction coefficient. A woven fabric, a knitted fabric, a non-woven fabric, or the like can be applied to the reinforcing fabric, and various fibers can be used as the fibers constituting the reinforcing fabric in accordance with requirements such as wear resistance and water absorption.

  For example, in Patent Document 1, a rib surface (friction transmission surface) is covered with a canvas (reinforcing cloth), and the canvas is stretchable in two predetermined directions. The canvas is an elastic yarn and at least one type of inelastic yarn. A V-ribbed belt is disclosed in which the inelastic yarn comprises a cellulose-based fiber or yarn. As a canvas (reinforcing cloth) used for such a belt, a seamless or seamed tubular canvas is exemplified (see paragraph 0020 of Patent Document 1).

  In general, the reinforcing fabric is subjected to an adhesion treatment in order to enhance the adhesion of the belt body to the rubber composition. At that time, since the seamless tubular canvas exemplified in Patent Document 1 cannot be applied with continuous bonding, productivity is reduced, or a seamless tubular canvas having a circumferential length corresponding to the belt length is used. Since it is necessary to prepare, there is a problem that the work in progress increases.

  Therefore, in order to enable continuous bonding treatment of the reinforcing cloth and improve productivity, the long reinforcing cloth that enables continuous bonding treatment is subjected to the bonding treatment, and the reinforcement after finishing the bonding treatment. It is practiced to fabricate a cylindrical reinforcing cloth by seaming (joining) the cloth. In this case, thermal welding or ultrasonic welding has been used as a joining method of the reinforcing cloth.

Special table 2010-539394 gazette

  However, the joining by heat welding or ultrasonic welding has a problem that cracks at the joining part and, consequently, peeling of the reinforcing cloth easily occur due to insufficient strength of the joining part, and improvement has been demanded.

  Then, the subject of this invention is improving the intensity | strength of the junction part of the knitted fabric (reinforcement cloth) which coat | covers the friction transmission surface of a friction transmission belt.

  In order to solve the above problems, the friction transmission belt of the present invention is characterized in that the friction transmission surface is covered with a knitted fabric having a joint portion, and the joint portion is sewn with a sewing thread.

  According to the above configuration, since the joint portion of the knitted fabric is sewn with the sewing thread, the strength of the joint portion is increased, and when the friction transmission belt is used, the occurrence of cracks in the joint portion is suppressed. Since peeling can be suppressed, the life of the friction transmission belt is improved. Thereby, the intensity | strength of a junction part can be improved rather than the heat welding and the ultrasonic welding which are the joining methods of the junction part of the knitted fabric conventionally performed.

  In the friction transmission belt, the present invention is characterized in that stitching of the joint portion is staggered stitching.

  The knitted fabric needs to be stretched following the rubber flow when the rubber constituting the friction transmission belt is vulcanized. Therefore, the stitches of the joint portion of the knitted fabric are staggered so that the strength of the joint portion can be increased without inhibiting the stretch of the knitted fabric during vulcanization.

  In the friction transmission belt, the present invention is characterized in that the zigzag stitching of the joint is a three-point zigzag or a four-point zigzag.

  When the zigzag stitch is 2-point zigzag, the strength of the joint may be insufficient because the needle drop points are small. Therefore, by using staggered stitches with 3 or 4 needle drop points, the needle drop points increase and the strength of the joint can be further increased. In addition, for example, in the case where the knitted fabrics are overlapped with each other at the joint portion (overlap portion), the overlap portion is compressed by forming a needle drop point in the overlap portion, and the non-overlap portion Can be reduced (the difference in thickness can be reduced).

Further, the present invention has an overlap portion in which the knitted fabrics overlap each other in the joint portion of the friction transmission belt,
The overlap portion is stitched.

  According to the above configuration, in the case where the overlap portion where the knitted fabrics overlap is formed at the joint portion, and the knitted fabric without the overlap portion where the knitted fabrics overlap is sewn by sewing the overlap portion. Compared to (sewing in a state where the knitted fabrics are butted together), the strength of the joint can be increased.

  In the friction transmission belt according to the present invention, a length of the overlap portion in a belt circumferential direction is 2 mm or more and 20 mm or less.

  If the length of the overlap portion in the belt circumferential direction is less than 2 mm, the strength of the joint portion may not be sufficient, and cracks may not be sufficiently suppressed. On the other hand, if the length of the overlap portion in the belt circumferential direction exceeds 20 mm, the effect of the step between the overlap portion and the non-overlap portion increases, resulting in the appearance deterioration and the occurrence of abnormal noise and tension fluctuations. Is concerned. Therefore, by setting the length of the overlap portion to 2 mm or more and 20 mm or less, it is possible to obtain a configuration that balances the strength of the joint portion and the suppression of the above-described problems.

  Further, the present invention is characterized in that, in the joining portion of the friction transmission belt, a sewing width in the belt circumferential direction is 0.5 mm or more larger than a length in the belt circumferential direction of the overlap portion.

  According to the said structure, the intensity | strength of a junction part can be raised more by pressing down the whole overlap part with a sewing thread.

  In the friction transmission belt according to the present invention, the stitches of the joint portion are staggered stitches, and the stitch pitch, which is a distance between turning points in the belt width direction of the staggered stitches, is 0.3 mm or more and 2 mm or less. It is characterized by being.

  According to the said structure, a seam pitch can be made fine by making a stitch pitch into the range of 0.3 mm or more-2 mm or less, and the intensity | strength of a junction part can be raised.

In the friction transmission belt according to the present invention, a plurality of ribs extending in the belt circumferential direction are formed on the friction transmission surface.
One or more needle drop points for the stitching are provided at the tip of the rib.

  According to the said structure, the intensity | strength of a junction part can be raised more by making a stitch pitch small, for example so that at least 1 needle drop point may exist in the front-end | tip part of each rib.

In the friction transmission belt according to the present invention, a plurality of ribs extending in the belt circumferential direction are formed on the friction transmission surface.
The stitching of the joint is staggered,
A stitch pitch, which is a distance between turning points in the belt width direction of the staggered stitch, is 0.5 times or less of a rib pitch, which is a length of the rib in the belt width direction.

  According to the said structure, a seam pitch can be made fine by making a seam pitch 0.5 times or less of a rib pitch, and the intensity | strength of a junction part can be raised.

  In the friction transmission belt according to the present invention, the sewing thread has a melting point or a softening point of 180 ° C. or higher.

  If the melting point or softening point of the sewing thread is less than 180 ° C., the effect of increasing the strength of the joint portion by melting or softening due to heat during vulcanization is lost. Therefore, by using a sewing thread having a melting point or softening point of 180 ° C. or higher, the strength of the joint can be maintained even after vulcanization without being melted by heat during vulcanization.

  In the friction transmission belt according to the present invention, the sewing thread is a composite thread in which a synthetic fiber is used as a core thread and the periphery of the core thread is covered with a cellulosic fiber.

  By using a composite yarn with synthetic fiber as the core yarn and surrounding it with cellulosic fiber as the sewing thread used for stitching the joint, good elongation is given to the sewing thread, so it does not hinder the stretch of the knitted fabric There are benefits. Further, the presence of cellulosic fibers on the surface of the sewing thread 61 can improve the water absorption and sound resistance. Furthermore, the presence of the synthetic fiber at the core of the sewing thread 61 is resistant to wear and can maintain the strength of the joint.

  In the friction transmission belt according to the present invention, the sewing thread may be made of nylon fiber.

  By using nylon fibers that are excellent in elasticity for the sewing thread that is used for stitching the joint portion, it is possible to suppress a decrease in the flexibility of the belt, and thus to maintain the strength of the joint portion.

  In the friction transmission belt, the present invention may be characterized in that the sewing thread is made of an aramid fiber.

  By using an aramid fiber excellent in wear resistance as a sewing thread used for stitching the joint, the strength of the joint can be maintained.

  Moreover, this invention is a manufacturing method of a friction transmission belt characterized by including the sewing process which stitch | sutures the junction part of the knitted fabric which coat | covers a friction transmission surface with a sewing machine.

  According to the above method, the stitch width and stitch pitch interval are accurate and the productivity is excellent by sewing the joint portion of the knitted fabric with the sewing machine.

Further, the present invention, in the suturing step of the manufacturing method of the friction transmission belt,
The stitching is staggered;
A stitch pitch, which is a distance between turning points in the belt width direction of the zigzag stitch, is 0.2 mm to 1.5 mm.

  According to the above method, even if the stitch pitch is extended during the formation of the friction transmission belt by setting the stitch pitch in the range of 0.2 mm to 1.5 mm or less in the stitching process, the stitch pitch after the formation of the friction transmission belt is increased. Can be in the range of 0.3 mm to 2 mm. Thereby, a seam can be made fine and the intensity | strength of a junction part can be raised.

Further, the present invention, in the suturing step of the manufacturing method of the friction transmission belt,
Stitching of the knitted fabric covering the friction transmission surface formed with a plurality of ribs extending in the belt circumferential direction is staggered,
The stitch pitch, which is the distance between the turning points in the belt width direction of the staggered stitch, is 0.35 times or less the rib pitch, which is the length of the rib in the belt width direction.

  According to the above method, by setting the stitch pitch in the stitching process to 0.35 times or less of the rib pitch, even if the stitch pitch is increased during the formation of the friction transmission belt, the stitch pitch after the friction transmission belt is formed is equal to the rib pitch. It can be 0.5 times or less. Thereby, a seam can be made fine and the intensity | strength of a junction part can be raised.

Further, the present invention provides a method for producing the friction transmission belt,
In the joint part, including an overlap step of overlapping the knitted fabrics to form an overlap part,
In the suturing step, an adhesive is not applied between the knitted fabric and the knitted fabric overlapped in the overlap portion.

  If reinforcement is applied by applying an adhesive such as rubber glue between the knitted fabrics overlapped at the overlap part, the thickness of the overlap part will increase and the stress distribution will become non-uniform and cracks will easily occur. Become. Therefore, since the strength of the joint is sufficiently secured by the overlap process and the stitching process, by omitting reinforcement with an adhesive such as rubber glue, the occurrence of cracks can be prevented while ensuring the strength of the joint. Furthermore, the number of manufacturing steps can be reduced and the productivity can be improved.

  The strength of the joint portion of the knitted fabric (reinforcing fabric) covering the friction transmission surface of the friction transmission belt can be improved.

It is a schematic perspective view explaining the example of the belt transmission device using the V-ribbed belt which concerns on this embodiment. It is a cross-sectional view of the V-ribbed belt along the AA ′ cross section of FIG. 1. It is explanatory drawing which shows the stitching | suture aspect of the junction part of the knitted fabric in the V-ribbed belt which concerns on this embodiment. It is explanatory drawing of the staggered stitch in the overlap part of the junction part of the V-ribbed belt which concerns on this embodiment. It is explanatory drawing of the staggered stitch in the butt | matching aspect of the junction part of the V-ribbed belt which concerns on this embodiment. It is explanatory drawing of the "overlap" and "butting" of the junction part of the V-ribbed belt which concerns on this embodiment. It is explanatory drawing of the knitted fabric at the time of sewing. It is explanatory drawing of the knitted fabric after V-ribbed belt shaping | molding. It is a conceptual diagram explaining the manufacturing method of a V-ribbed belt. It is explanatory drawing of the V-ribbed belt used in the durability test which concerns on an Example. It is a layout of the multi-axis running test machine used in the endurance test concerning an example. It is explanatory drawing about the stitching | suture location in the overlap part of the junction part of the V-ribbed belt which concerns on an Example. It is explanatory drawing which shows the stitching | suture aspect by the flat seamer of the junction part of the V-ribbed belt which concerns on a reference example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a belt transmission device for driving an auxiliary machine using a V-ribbed belt 1 as an example of a friction transmission belt according to the present invention. This belt transmission is the simplest example in which the drive pulley 21 and the driven pulley 22 are provided one by one, and the V-ribbed belt 1 is wound around the drive pulley 21 and the driven pulley 22. The endless V-ribbed belt 1 is formed with a plurality of V-shaped rib portions 2 extending in the belt circumferential direction on the inner peripheral side, and on the outer peripheral surfaces of the drive pulley 21 and the driven pulley 22, A plurality of V-shaped grooves 23 into which the respective rib portions 2 are fitted are provided.

(Configuration of V-ribbed belt 1)
As shown in FIG. 2, the V-ribbed belt 1 includes an extension layer 3 that forms the belt back surface on the outer periphery side, a compression layer 4 provided on the inner periphery side of the extension layer 3, and the extension layer 3 and the compression layer 4. The surface of the rib portion 2 is provided with a core wire 5 extending in the circumferential direction of the belt embedded in between, and a plurality of V-shaped rib portions 2 extending in the circumferential direction of the belt are formed in the compression layer 4. Is covered with a knitted fabric 6 having a joint 60 sewn with a sewing thread. As will be described later, the stretch layer 3 and the compression layer 4 are both formed of a rubber composition. If necessary, an adhesive layer may be provided between the stretch layer 3 and the compression layer 4. This adhesive layer is provided for the purpose of improving the adhesion between the core wire 5 and the stretched layer 3 and the compressed layer 4, but is not essential. The form of the adhesive layer may be a form in which the entire core wire 5 is embedded in the adhesive layer, or a form in which the core wire 5 is embedded between the adhesive layer and the stretched layer 3 or between the compression layer 4.

(Compression layer 4)
Examples of rubber components of the rubber composition forming the compression layer 4 include vulcanizable or crosslinkable rubbers such as diene rubbers (natural rubber, isoprene rubber, butadiene rubber, chloroprene rubber, styrene butadiene rubber, acrylonitrile butadiene rubber, hydrogen Nitrile rubber, mixed polymer of hydrogenated nitrile rubber and unsaturated carboxylic acid metal salt, etc.), ethylene-α-olefin elastomer, chlorosulfonated polyethylene rubber, alkylated chlorosulfonated polyethylene rubber, epichlorohydrin rubber, acrylic rubber, Examples include silicone rubber, urethane rubber, and fluorinated rubber.

  Of these, those obtained by forming an unvulcanized rubber layer with a rubber composition containing sulfur or an organic peroxide, and vulcanizing or crosslinking the unvulcanized rubber layer are preferable. An ethylene-α-olefin elastomer (ethylene-α-olefin-based rubber) is preferable because it has ozone resistance, heat resistance, and cold resistance and is excellent in economy. Examples of the ethylene-α-olefin elastomer include ethylene-α-olefin rubber and ethylene-α-olefin-diene rubber. Examples of the α-olefin include propylene, butene, pentene, methylpentene, hexene and octene. These α-olefins can be used alone or in combination of two or more. In addition, examples of the diene monomer used as a raw material include non-conjugated diene monomers such as dicyclopentadiene, methylene norbornene, ethylidene norbornene, 1,4-hexadiene, and cyclooctadiene. These diene monomers can be used alone or in combination of two or more.

  Representative examples of the ethylene-α-olefin elastomer include ethylene-α-olefin rubber (ethylene-propylene rubber), ethylene-α-olefin-diene rubber (ethylene-propylene-diene copolymer), and the like. In the ethylene-α-olefin elastomer, the ratio of ethylene to α-olefin (the mass ratio of the former / the latter) is 40/60 to 90/10, preferably 45/55 to 85/15, more preferably 55/45. The range of ~ 80/20 is good. The proportion of diene can be selected from the range of 4 to 15% by mass, for example, 4.2 to 13% by mass, preferably 4.4 to 11.5% by mass. The iodine value of the ethylene-α-olefin elastomer containing the diene component is, for example, 3 to 40, preferably 5 to 30, and more preferably 10 to 20. If the iodine value is too small, vulcanization of the rubber composition will be insufficient, and wear and sticking will easily occur.If the iodine value is too large, the scorch of the rubber composition will become short and difficult to handle, and heat resistance will be increased. There is a tendency to decrease.

  Examples of the organic peroxide for crosslinking the unvulcanized rubber layer include diacyl peroxide, peroxyester, dialkyl peroxide (dicumyl peroxide, t-butylcumyl peroxide, 1,1-di-butylperoxy-3 , 3,5-trimethylcyclohexane 2,5-dimethyl-2,5-di (t-butylperoxy) -hexane, 1,3-bis (t-butylperoxy-isopropyl) benzene, di-t-butylper Oxide) and the like. These organic peroxides can be used alone or in combination of two or more. Furthermore, the organic peroxide has a one-minute half-life of 150 ° C. to 250 ° C., preferably about 175 ° C. to 225 ° C. by thermal decomposition.

  The ratio of the vulcanizing agent or crosslinking agent (especially organic peroxide) in the unvulcanized rubber layer is 1 to 10 parts by mass in terms of solid content with respect to 100 parts by mass of the rubber component (such as ethylene-α-olefin elastomer). The amount is preferably 1.2 to 8 parts by mass, more preferably 1.5 to 6 parts by mass.

  The rubber composition may contain a vulcanization accelerator. Examples of the vulcanization accelerator include thiuram accelerators, thiazole accelerators, sulfenamide accelerators, bismaleimide accelerators, urea accelerators, and the like. These vulcanization accelerators can be used alone or in combination of two or more. The ratio of the vulcanization accelerator is 0.5 to 15 parts by mass, preferably 1 to 10 parts by mass, and more preferably 2 to 5 parts by mass with respect to 100 parts by mass of the rubber component in terms of solid content.

  The rubber composition may further contain a co-crosslinking agent (crosslinking aid or co-vulcanizing agent) in order to increase the degree of crosslinking and prevent adhesive wear and the like. Examples of co-crosslinking agents include conventional crosslinking aids such as polyfunctional (iso) cyanurates (triallyl isocyanurate, triallyl cyanurate, etc.), polydienes (1,2-polybutadiene, etc.), and metal salts of unsaturated carboxylic acids. (Zinc (meth) acrylate, magnesium (meth) acrylate, etc.), oximes (quinone dioxime, etc.), guanidines (diphenylguanidine, etc.), polyfunctional (meth) acrylates (ethylene glycol di (meth) acrylate, butane Diol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, etc.), bismaleimides (N, N′-m-phenylenebismaleimide, etc.) and the like. These crosslinking aids can be used alone or in combination of two or more. The ratio of the crosslinking aid (total amount when combining multiple types) is 0.01 to 10 parts by mass, preferably 0.05 to 8 parts by mass, based on 100 parts by mass of the rubber component, in terms of solid content. Good.

  Moreover, the rubber composition may contain a short fiber as needed. Short fibers include cellulosic fibers (cotton, rayon, etc.), polyester fibers (PET, PEN fibers, etc.), aliphatic polyamide fibers (6 nylon fibers, 66 nylon fibers, 46 nylon fibers, etc.), aromatic polyamide fibers ( p-aramid fiber, m-aramid fiber, etc.), vinylon fiber, polyparaphenylene benzobisoxazole fiber and the like. These short fibers may be subjected to conventional adhesion treatment or surface treatment such as treatment with an RFL solution in order to improve dispersibility and adhesion in the rubber composition. The ratio of the short fiber is 1 to 50 parts by mass, preferably 5 to 40 parts by mass, and more preferably 10 to 35 parts by mass with respect to 100 parts by mass of the rubber component.

  Further, the rubber composition may be prepared by adding conventional additives such as vulcanization aids, vulcanization retarders, reinforcing agents (carbon black, silicon oxide such as hydrous silica), fillers (clay, carbonic acid) as necessary. Calcium, talc, mica, etc.), metal oxides (zinc oxide, magnesium oxide, calcium oxide, barium oxide, iron oxide, copper oxide, titanium oxide, aluminum oxide, etc.), plasticizers (paraffinic oil, naphthenic oil, process) Oils, etc.), processing agents or processing aids (stearic acid, metal stearate, wax, paraffin, fatty acid amide, etc.), anti-aging agents (antioxidants, thermal anti-aging agents, anti-bending cracks, Ozone deterioration prevention agent), colorant, tackifier, coupling agent (silane coupling agent, etc.), stabilizer (ultraviolet absorber, antioxidant) Antiozonants, thermal stabilizers), lubricants (graphite, molybdenum disulfide, ultrahigh molecular weight polyethylene, etc.), a flame retardant, an antistatic agent and the like. The metal oxide may act as a crosslinking agent. These additives can be used alone or in combination of two or more. Further, the ratio of these additives can be selected from a conventional range depending on the type. For example, the ratio of the reinforcing agent (carbon black, silica, etc.) is 10 to 200 parts by mass (100 parts by mass of the rubber component). Preferably 20 to 150 parts by mass), the ratio of metal oxide (such as zinc oxide) is 1 to 15 parts by mass (preferably 2 to 10 parts by mass), and the ratio of plasticizer (oils such as paraffin oil) is 1 to 1. 30 mass parts (preferably 5-25 mass parts) and the ratio of a processing agent (stearic acid etc.) are 0.1-5 mass parts (preferably 0.5-3 mass parts).

(Extension layer 3)
The stretch layer 3 may be formed of the same rubber composition as the compression layer 4 (rubber composition containing a rubber component such as ethylene-α-olefin elastomer), or may be formed of a fabric (reinforcing fabric) such as a canvas. Also good. Examples of the reinforcing cloth include cloth materials such as woven cloth, wide-angle sail cloth, knitted cloth, and non-woven cloth. Among these, a woven fabric woven in the form of plain weave, twill weave, satin weave, or a wide-angle sailcloth or knitted fabric in which the crossing angle between the warp and the weft is about 90 ° to 130 ° is preferable. As the fibers constituting the reinforcing cloth, the same fibers as the short fibers can be used. The reinforcing cloth may be treated with an RFL solution (such as a dipping process), and then subjected to a coating process or the like to form a canvas with rubber.

  The stretch layer 3 is preferably formed of the same rubber composition as the compression layer 4. As the rubber component of this rubber composition, the same type or type of rubber as the rubber component of the compression layer 4 is often used. Further, the ratio of additives such as a vulcanizing agent or a crosslinking agent, a co-crosslinking agent, and a vulcanization accelerator can be selected from the same range as that of the rubber composition of the compression layer 4.

  The rubber composition of the stretch layer 3 may contain short fibers similar to those of the compression layer 4 in order to suppress the generation of abnormal noise due to the adhesion of the back rubber when the back surface is driven. The form of the short fiber may be linear, or may be a partially bent shape (for example, a milled fiber described in JP-A-2007-120507). When the V-ribbed belt 1 is running, cracks may occur in the circumferential direction of the belt in the stretch layer 3 and the V-ribbed belt 1 may be broken, but this is prevented by orienting the short fibers in the belt width direction or in a random direction. be able to. Further, in order to suppress the generation of abnormal noise during backside driving, an uneven pattern may be provided on the surface of the stretch layer 3 (belt backside). Examples of the concavo-convex pattern include a knitted fabric pattern, a woven fabric pattern, a suede woven fabric pattern, an embossed pattern (for example, a dimple shape), and the size and depth are not particularly limited.

(Core 5)
The core 5 is not particularly limited, and polyester fiber (polybutylene terephthalate fiber, polyethylene terephthalate fiber, polytrimethylene terephthalate fiber, polyethylene naphthalate fiber, etc.), aliphatic polyamide (nylon) fiber (6 nylon fiber, 66 nylon) Fiber, 46 nylon fiber, etc.), aromatic polyamide (aramid) fiber (copolyparaphenylene, 3,4′oxydiphenylene, terephthalamide fiber, poly-p-phenylene terephthalamide fiber, etc.), polyarylate fiber, glass fiber, A cord formed of carbon fiber, PBO fiber, or the like can be used. These fibers can be used alone or in combination of two or more. These fibers are appropriately selected according to the expansion coefficient of the flexible jacket 51 described later. For example, in the case of high elongation such that the expansion coefficient exceeds 2%, polyester fibers having a low elastic modulus (particularly low elastic polybutylene terephthalate fibers) and nylon fibers (particularly 66 nylon fibers, 46 nylon fibers) are preferable. This is because, in the case of a fiber having a high elastic modulus such as an aramid fiber or a PBO fiber, the fiber cannot sufficiently expand even when the flexible jacket 51 expands, and the pitch of the core 5 embedded in the V-ribbed belt 1 This is because the line is not stable, or the proper shape of the rib portion 2 is not formed. For this reason, in order to use a fiber with a high elastic modulus, it is preferable to set the expansion coefficient of the flexible jacket 51 low (for example, about 1%).

(Knitted fabric 6: constituent material)
The knitted fabric 6 may be either a weft knitting or a warp knitting, but the weft knitting is excellent in stretchability, so that it can be easily attached by a friction transmission surface in which irregularities are formed in the rib portion 2. Examples of the weft knitted in a single layer include flat knitting (Tengu knitting), rubber knitting, tuck knitting, pearl knitting, kanoko knitting (Omotano, Ura kanoko, Namika kanoko), etc. Examples include a smooth knitting, an interlock knitting, a double rib knitting, a single picket knitting, a punch Rome knitting, a Milan rib knitting, a double jersey knitting, and a Kanoko knitting (both sides Kanoko). Examples of knitted warp knitted in a single layer include single denby and single cord, and those knitted in multiple layers include half tricot, double denby, double atlas, double cord and double tricot. .

  Further, as the yarn for knitting the knitted fabric 6, a yarn made of a single type of fiber (single yarn) or a yarn made of a plurality of types of fibers (composite yarn) can be used. These can be used alone, but can be used in combination because they can impart different characteristics to the knitted fabric 6. For example, the knitted fabric 6 is composed of a polyester-based composite yarn and a cellulose-based natural spun yarn (for example, cotton yarn). May be organized. The polyester composite yarn is a composite yarn containing polyester fibers and fibers other than polyester fibers. The polyester composite yarn may be a bulky processed yarn. The bulky processed yarn is a processed yarn having a larger cross section by causing the fibers to bend (crimpability) or by covering the core yarn with another yarn. Bulky processed yarns include conjugate yarns, covering yarns, crimped yarns, woolly processed yarns, taslan processed yarns, interlaced yarns, etc., but polyester-based composite yarns are preferably conjugate yarns and covering yarns. .

  The conjugate yarn has a cross-sectional structure in which two types of polymers are bonded together in the fiber axis direction. When heat is applied during manufacturing or processing, crimping occurs due to the difference in shrinkage between the two polymers, resulting in a bulky yarn. . For example, a conjugate yarn made of polytrimethylene terephthalate (PTT) and polyethylene terephthalate (PET) (PTT / PET conjugate yarn), or a conjugate yarn made of polybutylene terephthalate (PBT) and polyethylene terephthalate (PET) (PBT / PET) Conjugate yarn). Further, the covering yarn is a yarn in which the bulk of the entire yarn is increased by covering (covering) the periphery of the core yarn with another yarn. For example, covering yarn (PET / PU covering yarn) whose surface is covered with polyethylene terephthalate (PET) and polyurethane (PU) yarn with excellent elasticity, and polyamide (PA) with PU as the core Covering yarn (PA / PU covering yarn) covered with. Of these, the polyester composite yarn contained in the knitted fabric 6 is preferably a PTT / PET conjugate yarn or a PET / PU covering yarn excellent in stretchability and abrasion resistance.

  Cellulose-based natural spun yarn includes bamboo fiber, sugarcane fiber, seed hair fiber (cotton fiber (cotton linter), kapok, etc.), gin leather fiber (eg, hemp, kouzo, mitsumata, etc.), leaf fiber (eg, Manila hemp, New Zealand) Examples thereof include yarn obtained by spinning cellulose fibers (pulp fibers) derived from natural plants such as hemp), cellulose fibers derived from animals such as wool, silk, and squirt cellulose, bacterial cellulose fibers, and algal cellulose. Among these, cotton fiber is preferable in terms of excellent water absorption.

  The knitting ratio of the cellulosic natural spun yarn is preferably 50 to 95% by mass. The knitted fabric structure may be a single layer or a multilayered knitted fabric 6, and a multilayered knitted fabric structure is preferable in order to more reliably prevent the rubber from seeping out from the belt body.

By knitting the knitted fabric including the bulky processed yarn, the bulkiness of the knitted fabric can be increased. The bulkiness of the knitted fabric 6 is preferably 2.0 cm ³ / g or more, and more preferably 2.4 cm ³ / g or more. The upper limit is not particularly limited, for example, 4.0 cm ³ / g or less, or 3.5 cm ³ / g may be less. The bulkiness (cm ³ / g) is obtained by dividing the thickness (cm) of the knitted fabric 6 by the mass (g / cm ² ) per unit area. It is also preferable to provide a bulky layer of the knitted fabric on the friction transmission surface in order to more surely prevent the rubber of the belt body from seeping into the friction transmission surface.

  When the knitted fabric 6 has a multi-layered knitted fabric structure, by arranging many cellulose-based natural spun yarns having excellent water absorption in the thickness direction of the knitted fabric 6 in the layer on the friction transmission surface side, Water absorption can be further increased. When knitting a multi-layered knitted fabric, one layer is knitted only with cellulose-based natural spun yarn, or cellulose-based natural spun yarn and polyester-based composite yarn, and the other layer is knitted with only polyester-based composite yarn. Thus, a multi-layer knitted fabric in which a large amount of cellulose-based natural spun yarn is arranged in one layer can be knitted. By disposing a layer with a large amount of cellulose-based natural spun yarn on the friction transmission surface side, water absorption at the friction transmission surface can be further increased.

  The knitted fabric 6 can contain or adhere a surfactant or a hydrophilic softener as a hydrophilic treatment agent. Thus, when a hydrophilization treatment agent is contained in or adhered to the knitted fabric 6, when water droplets adhere to the friction transmission surface (knitted fabric 6), the water droplets are promptly applied to the surface of the knitted fabric 6 subjected to the hydrophilization treatment. The wet film spreads to form a water film, and is further absorbed by the cellulose-based natural spun yarn of the knitted fabric 6 so that the water film disappears on the friction transmission surface. Therefore, a decrease in the friction coefficient of the friction transmission surface in the wet state is further suppressed.

  As the hydrophilic treatment agent, a surfactant or a hydrophilic softening agent can be used. As a method for containing or attaching these hydrophilic treatment agents to the knitted fabric, a method of spraying the hydrophilic treatment agent onto the knitted fabric, a method of coating the knitted fabric with the hydrophilic treatment agent, or a hydrophilic treatment of the knitted fabric A method of immersing in an agent can be employed. In the case of using a hydrophilizing agent as a surfactant, in the belt manufacturing method described later, a surfactant is applied to the surface of a cylindrical outer mold in which a plurality of rib molds are engraved on the inner peripheral surface. A method of incorporating a surfactant into the knitted fabric by vulcanization molding can also be employed. Among these methods, the method of immersing the knitted fabric in the hydrophilizing agent is preferable because the hydrophilic softening agent can be contained and adhered more easily and more uniformly.

  Surfactant is a generic term for substances that have a hydrophilic group that is easily compatible with water and a hydrophobic group (lipophilic group) that is easily compatible with oil, and works to uniformly mix polar and nonpolar substances. In addition to the above, there is an effect that the surface tension is reduced to increase the wettability, and the surfactant is interposed between the substances to reduce the friction at the interface.

  The kind of surfactant is not specifically limited, An ionic surfactant, a nonionic surfactant, etc. can be used. The nonionic surfactant may be a polyethylene glycol type nonionic surfactant or a polyhydric alcohol type nonionic surfactant.

  Polyethylene glycol type nonionic surfactants have a hydrophilic group formed by adding ethylene oxide to a hydrophobic base component having a hydrophobic group, such as higher alcohol, alkylphenol, higher fatty acid, higher polyhydric alcohol higher fatty acid ester, higher fatty acid amide, and polypropylene glycol. It is a given nonionic surfactant.

Examples of the higher alcohol as the hydrophobic base component include C _10-30 saturated alcohols such as lauryl alcohol, tetradecyl alcohol, cetyl alcohol, octadecyl alcohol, aralkyl alcohol, and C _10-26 unsaturated alcohols such as oleyl alcohol. It can be illustrated. Examples of the alkylphenol include C _4-16 alkylphenols such as octylphenol and nonylphenol.

Higher fatty acids of the hydrophobic base component include saturated fatty acids (eg, C _10-30 saturated fatty acids such as myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, serotic acid, montanic acid, preferably C _12-28 saturated fatty acids, more preferably C _14-26 saturated fatty acids, especially C _16-22 saturated fatty acids, etc .; oxycarboxylic acids such as hydroxystearic acid, etc., unsaturated fatty acids (eg oleic acid, erucic acid, erucic acid) And C _10-30 unsaturated fatty acids such as linoleic acid, linolenic acid and eleostearic acid). These higher fatty acids may be used alone or in combination of two or more.

The polyhydric alcohol higher fatty acid ester is an ester of a polyhydric alcohol and the higher fatty acid and has an unreacted hydroxyl group. Examples of polyhydric alcohols include alkanediols (such as C _2-10 alkanediols such as ethylene glycol, propylene glycol, and butanediol), alkanetriols (such as glycerin, trimethylolethane, trimethylolpropane), and alkanetetraols (pentaerythritol, Examples thereof include diglycerin and the like, alkanehexaol (such as dipentaerythritol, sorbitol, and sorbit), alkaneoctaol (such as sucrose), and alkylene oxide adducts thereof (such as C _2-4 alkylene oxide adducts).

Hereinafter, when “oxyethylene”, “ethylene oxide” or “ethylene glycol” is represented by “EO”, and “oxypropylene”, “propylene oxide” or “propylene glycol” is represented by “PO”, the polyethylene glycol type Specific examples of the ionic surfactant include, for example, polyEO higher alcohol ethers (polyEO such as polyEO lauryl ether and polyEO stearyl ether).
C _10-26 alkyl ether), C _10-26 higher alcohols -EO-PO adducts, such as poly-EO poly PO alkyl ether; poly EO octylphenyl ether, alkylphenol -EO adduct such as poly EO nonyl phenyl ether; poly EO Fatty acid-EO adducts such as monolaurate, polyEO monooleate, polyEO monostearate; glycerin mono or di-higher fatty acid ester-EO adduct (glycerin mono or dilaurate, glycerin mono or dipalmitate, glycerin mono or distearate, glycerin mono or glycerol mono- or EO adducts of di- C _10-26 fatty acid esters such as dioleate), pentaerythritol higher fatty acid ester -EO adduct (pentaerythritol such as pentaerythritol distearate -EO adduct Mono or tri C _10-26 fatty acid esters -EO adduct, etc.), dipentaerythritol higher fatty acid ester -EO adduct, sorbitol higher fatty acid ester -EO adduct, sorbitol higher fatty acid ester -EO adduct, poly EO sorbitan monolaurate Polyhydric alcohol fatty acid ester-EO adducts such as sorbitan fatty acid ester-EO adducts such as sucrose, poly EO sorbitan monostearate, poly EO sorbitan tristearate, poly EO laurylamino Higher alkylamine-EO adducts such as ether and polyEO stearylaminoether; polyEO palm fatty acid monoethanolamide, polyEO lauric acid monoethanolamide, polyEO stearic acid monoethanolamide, polyEO Fatty acid amide-EO adducts such as oleic acid monoethanolamide; Fatty-EO adducts such as poly EO castor oil and poly EO hardened castor oil; Poly PO-EO adducts (poly EO-poly PO block copolymers, etc.) Etc. These polyethylene glycol type nonionic surfactants can be used alone or in combination of two or more.

  The polyhydric alcohol type nonionic surfactant is a nonionic surfactant in which a hydrophobic group such as a higher fatty acid is bonded to the polyhydric alcohol (especially alkanetriol or alkanehexaol such as glycerol, pentaerythritol, sucrose or sorbitol). It is an agent. Examples of the polyhydric alcohol type nonionic surfactant include glycerin fatty acid esters such as glycerin monostearate and glycerin monooleate, pentaerythritol fatty acid esters such as pentaerythritol monostearate and pentaerythritol beef tallow fatty acid ester, Sorbitan fatty acid esters such as sorbitan monolaurate, sorbitan monostearate, sorbitol fatty acid esters such as sorbitol monostearate, sucrose fatty acid esters, alkyl ethers of polyhydric alcohols, fatty acid amides of alkanolamines such as coconut fatty acid diethanolamide, Examples thereof include alkyl polyglycosides. These polyhydric alcohol type nonionic surfactants can also be used alone or in combination of two or more, and may be used in combination with the polyethylene glycol type nonionic surfactant.

  The ionic surfactants are alkylbenzene sulfonate, α-olefin sulfonate, long chain fatty acid salt, alkane sulfonate, alkyl sulfate, poly EO alkyl ether sulfate ester, naphthalene sulfonate formalin condensate, alkyl Anionic surfactants such as phosphates, cationic surfactants such as alkyltrimethylammonium salts and dialkyldimethylammonium salts, and amphoteric surfactants such as alkylbetaines and imidazoline derivatives may also be used.

Preferred surfactants are nonionic surfactants, especially polyethylene glycol type nonionic surfactants (eg poly EOC _10-26 alkyl ethers, alkylphenol-EO adducts, polyhydric alcohols C _10-26 fatty acid esters-EO Adducts, etc.).

  The hydrophilic softening agent as the hydrophilic treatment agent is a softening agent used for imparting flexibility to a fiber member such as a knitted fabric or a woven fabric, and imparts hydrophilicity. General softeners have various effects such as softening the fiber member, improving slippage, preventing wrinkles, and preventing shrinkage. The hydrophilic softening agent is slightly inferior to the surfactant in sound resistance when the belt is wet, but can improve the flexibility of the knitted fabric. There is an effect that it can be easily added by the friction transmission surface on which the unevenness is formed in the rib portion 2.

  Although it does not specifically limit as a hydrophilic softening agent, A polyether modified silicone softening agent and a polyester softening agent can be used. The polyether-modified silicone softener is a softener containing silicone modified with a hydrophilic polyether group. The polyether-modified silicone softener may be an emulsion in which silicone is dispersed in water together with a surfactant.

  Polyester softener is an emulsion softener in which a hydrophilic polyester resin is dispersed in water together with a surfactant, and since it has a high affinity with polyester fibers, it increases the hydrophilicity of the polyester composite yarn in the knitted fabric. Can do.

  In the present embodiment, a part of the knitted fabric 6 is made to contain and adhere a surfactant or a hydrophilic softening agent by an immersion treatment in which the knitted fabric 6 is immersed in a hydrophilic treatment agent. As the surfactant, a polyethylene glycol type nonionic surfactant was used, and the concentration of the treatment liquid was 0.5 to 30% by mass. Moreover, as a hydrophilic softening agent, the polyether modified silicone softener and the polyester softening agent were used, and the density | concentration of the process liquid was 1-10 mass%. The solvent of the treatment liquid containing the hydrophilic treatment agent is not particularly limited, and examples thereof include general-purpose solvents such as water, hydrocarbons, ethers, and ketones. These solvents may be used alone or as a mixed solvent.

  In any immersion treatment, the immersion time is not particularly limited. The immersion treatment temperature is not particularly limited, and may be performed at room temperature or under heating. Moreover, you may perform a drying process as needed after an immersion process. The drying treatment may be performed, for example, at a temperature of about 50 ° C. or higher, preferably about 100 ° C. or higher.

  In addition, the knitted fabric 6 is subjected to an adhesion treatment for the purpose of improving the adhesion with the rubber composition constituting the compression layer 4 (rubber composition forming the surface of the rib portion 2). As an adhesive treatment of such a knitted fabric 6, an immersion treatment in a resin-based treatment liquid in which an epoxy compound or an isocyanate compound is dissolved in an organic solvent (toluene, xylene, methyl ethyl ketone, etc.), resorcin-formalin-latex liquid (RFL liquid) ) And an immersion treatment in a rubber paste obtained by dissolving a rubber composition in an organic solvent. Other methods of adhesion treatment include, for example, a friction treatment in which the knitted fabric 6 and the rubber composition are passed through a calender roll and the rubber composition is imprinted on the knitted fabric 6, and a spreading treatment in which a rubber paste is applied to the knitted fabric 6. The coating process etc. which laminate | stack a rubber composition on the knitted fabric 6 are also employable. By bonding the knitted fabric 6 in this way, the adhesion to the compression layer 4 can be improved, and the knitted fabric 6 can be prevented from being peeled off when the V-ribbed belt 1 is running. Moreover, the abrasion resistance of the rib part 2 can also be improved by performing an adhesion process.

(Junction 60: suture method)
Although details will be described in the item of the method for manufacturing the V-ribbed belt 1 described later, the knitted fabric 6 used in the V-ribbed belt 1 of the present embodiment is subjected to an adhesion treatment on the long knitted fabric 6 and then subjected to the adhesion treatment. After both ends of the knitted fabric 6 are joined to create a tubular knitted fabric 6, the unvulcanized stretch layer sheet 3S and the unvulcanized compressed layer sheet 4S are wound and vulcanized. The surface of the rib portion 2 that becomes the friction transmission surface of the V-ribbed belt 1 is covered.

  Here, as shown in FIG. 3, the knitted fabric 6 used in the V-ribbed belt 1 has a joint portion 60 in which both ends of the long knitted fabric 6 are joined. The joint 60 is sewn with a sewing thread 61.

  In this embodiment, the sewing thread 61 is a composite thread in which polyester is used as a core thread and the periphery thereof is covered with cotton. The sewing thread 61 is not particularly limited, and a single thread such as a polyamide thread or a polyester thread such as nylon or aramid may be used, or the same thread as that knitting the knitted fabric 6 may be used. Good (refer to the item of the constituent material of the knitted fabric 6).

  As in this embodiment, when a composite yarn having a structure in which polyester as a synthetic fiber is covered with cotton as a cellulose fiber as a core yarn is used as the sewing yarn 61, good elongation is imparted to the sewing yarn 61. Therefore, there is an advantage that the elongation of the knitted fabric 6 is not hindered. Further, the presence of cellulosic fibers on the surface of the sewing thread 61 can improve the water absorption and sound resistance. Furthermore, the presence of the synthetic fiber at the core of the sewing thread 61 is resistant to wear and can maintain the strength of the joint portion 60.

  The melting point or softening point of the sewing thread 61 is preferably 180 ° C. or higher. If the melting point or softening point of the sewing thread 61 is less than 180 ° C., the effect of increasing the strength of the joint 60 by melting or softening due to heat during vulcanization in the manufacturing stage is lost. Therefore, by using the sewing thread 61 having a melting point or a softening point of 180 ° C. or higher, the strength of the joint portion 60 can be maintained even after vulcanization without being melted by heat during vulcanization in the manufacturing stage.

  Examples of the stitching method of the joint portion 60 of the knitted fabric 6 include zigzag stitching, overlock (lock stitching), and flat seamer. Among these, zigzag stitching is preferable because the elongation of the knitted fabric 6 required when the V-ribbed belt 1 is formed can be secured while increasing the strength of the joint portion 60. If the restraint by stitching is too strong, the stretch of the knitted fabric 6 at the joint portion 60 is suppressed, and there is a possibility that the shape defect of the V-ribbed belt 1 may occur. In that respect, if the zigzag stitching is performed, the elongation of the knitted fabric 6 is not strongly suppressed, so that the shape defect of the V-ribbed belt 1 hardly occurs.

  Also, as shown in FIGS. 4 and 5, zigzag stitching is performed by two-point zigzag, three-point zigzag, depending on the number of needle drop points in the stitch pitch SP, which is the distance between the turning points in the belt width direction of the sewing thread. It is classified into 4-point zigzag. The two-point zigzag is the most basic configuration, and the needle drop points are arranged only at the turning point (the apex portion of the zigzag portion of the sewing thread) and have two needle drop points within one stitch pitch SP. In addition to the folding point (vertical portion of the zigzag portion of the sewing thread), the three-point zigzag also has one needle drop point arranged in the middle of the folding point (between the vertex and the vertex of the zigzag portion of the sewing thread). There are three needle drop points within one stitch pitch SP. In addition to the folding point (vertical portion of the zigzag portion of the sewing thread), the four-point zigzag has two needle drop points arranged between the folding points (between the vertex and the vertex of the zigzag portion of the sewing thread). There are four needle drop points within one stitch pitch SP. Similarly, as the number of zigzag stitches such as 5-point zigzag and 6-point zigzag increases, the needle drop points arranged between the turning points increase. In the zigzag stitching of the joint portion 60 of the knitted fabric 6, a two-point zigzag, a three-point zigzag, and a four-point zigzag are preferable, and since there are many needle drop points and the strength of the joint 60 can be further increased, a three-point zigzag or four points A staggered pattern is more preferable, and a 4-point staggered pattern is particularly preferable.

  In addition, as shown in FIG. 8, in staggered stitching, it is preferable that at least one stitch dropping point of stitching is arranged at the distal end portion 2 </ b> A of each rib portion 2. By reducing the stitch pitch SP so that there is at least one needle drop point at the tip 2A of each rib portion 2, the strength of the joint portion 60 can be further increased.

(Jointing part 60: arrangement | positioning of the knitted fabric 6)
Further, as shown in FIG. 3, the knitted fabric 6 used in the V-ribbed belt 1 joins both ends of the long knitted fabric 6 at the joining portion 60. As shown in FIG. 5 and FIG. 6 (A), the joint 60 may be “abutted” so that the ends of the knitted fabric 6 do not overlap each other, as shown in FIG. 4 and FIG. 6 (B). In this way, the ends of the knitted fabric 6 may be “overlapped” so as to overlap each other. In the case of butting, since the thickness of the knitted fabric 6 is uniform even in the joint portion 60, there are advantages in terms of improving the appearance and preventing abnormal noise and tension fluctuations. On the other hand, it is preferable to make it overlap from the point which raises the intensity | strength of the junction part 60 (the intensity | strength of the junction part 60 can be raised compared with the case of butt | matching). In addition, in this embodiment, since the junction part 60 is stitched | sutured with a sewing thread, even if it is a case where the knitted fabric 6 is overlapped, the part (overlap part 62) overlapped in the junction part 60 is shown. It is possible to suppress the knitted fabric 6 from being compressed and increase the thickness of the knitted fabric 6 in the overlap portion 62, and it is possible to suppress the appearance deterioration, abnormal noise, and the occurrence of tension fluctuation.

  The overlap length L (the length of the overlap portion 62 in the belt circumferential direction) is the length of the overlap portion in the belt circumferential direction when the knitted fabric 6 is overlapped so that the ends overlap. 6 (B) and FIG. 7) are not particularly limited, but may be, for example, 1 mm or more, preferably 2 mm to 20 mm, more preferably 3 mm to 15 mm, and further 5 mm to 12 mm ( Particularly preferred is 8 mm to 12 mm. If the overlap length L is less than 2 mm, the effect of increasing the strength of the joint portion 60 may not be sufficient. Conversely, if the overlap length L exceeds 20 mm, there is a concern that appearance deterioration, abnormal noise, tension fluctuation, etc. are likely to occur. is there.

  In addition, when it overlaps so that the edge of the knitted fabric 6 may overlap, it is preferable not to adhere | attach between the overlapped knitted fabric 6 and the knitted fabric 6 with an adhesive agent. If reinforcement is performed by applying an adhesive such as rubber glue between the knitted fabric 6 and the knitted fabric 6 that are overlapped in the overlap portion 62, the thickness of the overlap portion 62 increases, resulting in uneven stress distribution and cracks. Is likely to occur. Therefore, since the strength of the joint portion 60 is sufficiently secured by sewing the sewing thread 61, the reinforcement by an adhesive such as rubber glue is omitted to prevent the occurrence of cracks while ensuring the strength of the joint portion 60. be able to.

(Joint 60: Sewing width SW)
As shown in FIG. 7, the sewing width SW, which is the distance between the turning points in the belt circumferential direction of the staggered stitch of the joint portion 60, can be set as appropriate. The strength of is reduced. Therefore, the turning point of the staggered stitch is arranged so as to straddle the overlap portion 62. The sewing width SW is preferably set in correspondence with the overlap length L of the overlap portion 62. Specifically, it is preferably 0.5 mm or more larger than the overlap length L. Is preferably larger than the overlap length L in the range of 0.8 mm to 2 mm. If the sewing width SW is larger than the overlap length L by 0.5 mm or more, the entire overlap portion 62 can be pressed with the sewing thread, so that the strength of the joint portion 60 is increased. Furthermore, when the sewing width SW is set to the overlap length L + 0.8 mm to +2 mm, the needle drop points are concentrated on the joint 60 while the entire overlap part 62 is pressed with the sewing thread, so that the strength of the joint 60 is further increased. Rise.

(Joint 60: stitch pitch SP)
The knitted fabric 6 stitched by zigzag stitching is stretched in the direction of the stitch pitch SP (belt width direction) when the V-ribbed belt 1 is formed. Therefore, the stitch pitch SP is different from that at the time of sewing in the manufacturing stage and after the V-ribbed belt 1 is formed, and is wider after the V-ribbed belt 1 is formed. Here, a stitch pitch (see FIG. 7) at the time of sewing in the manufacturing stage and a stitch pitch after molding the V-ribbed belt 1 (see FIG. 8) are distinguished.

  The stitch pitch SP is preferably narrow from the viewpoint of increasing the strength of the joint portion 60, and the stitch pitch SP at the time of sewing in the manufacturing stage is 0. 0 of the rib pitch RP, which is the length of the rib portion 2 in the belt width direction. It is preferably 5 times or less, and more preferably 0.35 times or less of the rib pitch RP. Since the stitch pitch SP after forming the V-ribbed belt 1 is wider than the stitch pitch SP at the time of sewing in the manufacturing stage, the stitch pitch SP after forming the V-ribbed belt 1 is 0.8 times the rib pitch RP. And more preferably 0.5 times or less of the rib pitch RP (see FIG. 8). By making the stitch pitch SP after forming the V-ribbed belt 1 0.8 times or less of the rib pitch RP, and further 0.5 times or less of the rib pitch RP, the stitches can be made fine, and the strength of the joint portion 60 can be reduced. Can be increased.

  The rib pitch RP can be 1.6 mm, 2.34 mm, 3.56 mm, 4.7 mm, 9.4 mm, etc., as defined in JIS B1858 (2005), but is widely used for driving automotive accessories. If the rib pitch RP is 3.56 mm, the stitch pitch SP at the time of stitching in the manufacturing stage is preferably 0.2 mm to 1.5 mm, and after the V-ribbed belt 1 is formed. For example, the stitch pitch SP is preferably 0.3 mm to 2 mm. By setting the stitch pitch SP after forming the V-ribbed belt 1 to be in the range of 0.3 mm to 2 mm, the stitches can be made fine and the strength of the joint portion 60 can be increased.

  According to the above configuration, since the joint portion 60 of the knitted fabric 6 is sewn with the sewing thread, the strength of the joint portion 60 is increased, and the occurrence of cracks in the joint portion 60 is suppressed when the V-ribbed belt 1 is used. Since peeling of the knitted fabric 6 can be suppressed, the life of the V-ribbed belt 1 is improved. Thereby, the intensity | strength of the junction part 60 can be improved rather than the heat welding and the ultrasonic welding which are the joining methods of the junction part 60 of the knitted fabric 6 conventionally performed.

  Moreover, by stitching the joint portion 60 of the knitted fabric 6 with staggered stitches having three or four needle drop points, the needle drop points are increased, and the strength of the joint portion 60 can be further increased. Further, when the knitted fabrics 6 are overlapped with each other at the joint portion 60 (overlap portion 62), a needle drop point is formed in the overlap portion 62, so that the overlap portion 62 is compressed and overlapped. It is possible to reduce the level difference from the portion that does not (the difference in thickness can be reduced).

(Manufacturing method of V-ribbed belt 1)
Below, the manufacturing method of the V-ribbed belt 1 is demonstrated. First, an adhesive treatment is applied to the long knitted fabric 6. And it is made to overlap so that the edge of the knitted fabric 6 which performed the adhesion | attachment process may overlap (refer FIG.6 (B): overlap process). Then, staggered stitches are carried out with a sewing machine so as to straddle the overlapped portion (overlap portion 62) (see FIG. 4: stitching step). Thereby, the cylindrical knitted fabric 6 which has the junction part 60 with which both ends were joined is created.

  In the stitching process, the joint 60 of the knitted fabric 6 is stitched with a sewing machine, so that the interval between the stitch width SW and the stitch pitch SP is accurate and the productivity is excellent.

  In the stitching step, the stitch pitch SP at the time of stitching is preferably 0.2 mm to 1.5 mm. By setting the range to the left, even if the seam pitch SP is extended when the V-ribbed belt 1 is formed, the seam pitch SP after forming the V-ribbed belt 1 can be in the range of 0.3 mm to 2 mm. Thereby, a seam can be made fine and the intensity | strength of the junction part 60 can be raised.

  In the stitching process, the stitch pitch SP at the time of stitching is 0.5 times or less of the rib pitch RP, which is the length of the rib portion 2 in the belt width direction, and further 0.35 times or less of the rib pitch RP. Preferably there is. By setting the range to the left, even if the stitch pitch SP is extended when the V-ribbed belt 1 is molded, the stitch pitch SP after the molding of the V-ribbed belt 1 is 0.8 times or less, more preferably 0.5 times or less of the rib pitch RP. can do. Thereby, a seam can be made fine and the intensity | strength of the junction part 60 can be raised.

  Further, in the suturing step, reinforcement may be performed by applying an adhesive between the overlapped knitted fabric 6 and the knitted fabric 6, but it is preferable not to reinforce with the adhesive. If reinforcement is performed by applying an adhesive such as rubber glue between the knitted fabric 6 and the knitted fabric 6 that are overlapped in the overlap portion 62, the thickness of the overlap portion 62 increases, resulting in uneven stress distribution and cracks. Is likely to occur. Therefore, since the strength of the joint portion 60 is sufficiently secured by stitching in the overlap step and the stitching step, the reinforcement of the joint portion 60 is ensured by omitting reinforcement by an adhesive such as rubber paste. Occurrence can be prevented, manufacturing man-hours can be reduced, and productivity can be improved.

  Next, as shown in FIG. 9 (a), an unvulcanized stretch layer sheet 3S is wound around an inner mold 52 having a flexible jacket 51 mounted on the outer peripheral surface, and the core wire 5 is spirally wound thereon. Then, an unvulcanized compressed layer sheet 4S and a tubular knitted fabric 6 created in the above stitching process are sequentially wound thereon to form a molded body 10. Thereafter, the inner mold 52 around which the molded body 10 is wound is set concentrically on the inner circumferential side of the outer mold 53 in which a plurality of rib molds 53a are formed on the inner circumferential surface. At this time, a predetermined gap is provided between the inner peripheral surface of the outer mold 53 and the outer peripheral surface of the molded body 10.

  Next, as shown in FIG. 9B, the flexible jacket 51 is expanded toward the inner peripheral surface of the outer mold 53 at a predetermined expansion rate (for example, 1 to 6%), and the compressed layer of the molded body 10 is then expanded. The sheet 4S and the knitted fabric 6 are press-fitted into the rib mold 53a of the outer mold 53, and vulcanization processing (for example, 160 ° C., 30 minutes) is performed in that state.

  Finally, as shown in FIG. 9C, the inner mold 52 is extracted from the outer mold 53, the vulcanized rubber sleeve 10A having the plurality of rib portions 2 is removed from the outer mold 53, and then added using a cutter. The rubber rubber sleeve 10 </ b> A is cut into a predetermined width along the circumferential direction to finish the V-ribbed belt 1. In addition, the manufacturing method of V-ribbed belt 1 is not restricted to the said method, For example, the other well-known method disclosed by Unexamined-Japanese-Patent No. 2004-82702 etc. is also employable.

  In the method for manufacturing the V-ribbed belt 1, the knitted fabric 6 needs to be stretched following the rubber flow when the rubber constituting the V-ribbed belt 1 is vulcanized. Therefore, by stitching the joint portion 60 of the knitted fabric 6 in a staggered manner, the strength of the joint portion 60 can be increased without hindering the expansion of the knitted fabric 6 during vulcanization.

(Other embodiments)
In the above embodiment, the V-ribbed belt 1 has been described as an example of the friction transmission belt. However, the present invention can be applied to a flat belt or a V belt as long as it is a friction transmission belt.

  In the above embodiment, the case where the ends of the knitted fabric 6 are mainly “overlapped” so as to overlap each other has been described. However, as shown in FIG. 5 and FIG. A configuration in which the ends are “abutted” so that the ends do not overlap each other may be employed.

  Next, V-ribbed belts according to Examples 1 to 17 and Comparative Examples having joint portions joined in the joining modes shown in Tables 2 to 7 were manufactured, and durability tests were performed.

  Examples 1 to 17 and the configurations and materials of the V-ribbed belt according to the comparative example will be described below.

  Table 1 shows the configurations of the rubber compositions that constitute the stretch layers and the compression layers of the V-ribbed belts according to Examples 1 to 17 and the comparative example.

EPDM polymer: manufactured by DuPont Dow Elastomer Japan, “Nodel IP3640”
Paraffin oil: “Diana Process Oil” manufactured by Idemitsu Kosan Co., Ltd.
Anti-aging agent: “Nonflex OD3” manufactured by Seiko Chemical Co., Ltd.
Organic peroxides: “Parkadox 14RP” manufactured by Kayaku Akzo Co., Ltd.

(Core)
An aramid cord having a 1100 dtex / 1 × 4 configuration was used for the core wire, and RFL treatment and overcoat treatment with rubber paste were performed.

(Knitted fabric)
For the knitted fabric, cotton spun yarn (40th count, one) as a water-absorbing fiber and PTT / PET conjugate composite yarn (fineness 84 dtex) as a second fiber are knitted, and the knitting structure is a weft knitting ( Kanoko (2 layers) knitted fabric (fiber member) was used. Further, the adhesion treatment rubber was dissolved in toluene so as to have a solid content concentration of 10% to form a rubber paste, and after the knitted fabric was immersed in the rubber paste, the adhesion treatment was performed by drying at 100 ° C. for 5 minutes.

(Production of V-ribbed belts according to Examples 1 to 8 and Comparative Example)
As shown in FIG. 10, three joint portions (Example 1, Example 2, Comparative Example) having different joining modes are provided in advance on the knitted fabric, and three joints having different joining manners are joined to one V-ribbed belt. The three joint modes can be compared and tested at the same time. Similarly, according to Example 3, Example 4, and Example 5, V-ribbed belts including three joint portions with different joining modes, and Examples 6, 7, and 8, A V-ribbed belt including three joint portions having different joining modes was prepared. The rib pitches of the V-ribbed belts according to Examples 1 to 8 and the comparative example were 3.56 mm, and the stitch pitch at the time of stitching the V-ribbed belts according to Examples 1 to 8 was 1 mm. The stitch pitch after molding was 1.4 mm. The sewing thread used for stitching the joint portions of the V-ribbed belts according to Examples 1 to 8 and Comparative Example was a composite thread in which polyester was used as a core thread and the periphery thereof was covered with cotton. Further, Example 3 is the same joining mode as Example 1.

(Manufacture of V-ribbed belts according to Examples 9 to 17)
As shown in FIG. 10, the V-ribbed belt including three joint portions with different stitch pitches according to Example 9, Example 10, and Example 11, Example 12, Example 13, and The V-ribbed belt including three joint portions with different suture materials according to the fourteenth embodiment, and the three places with different suture locations or suture materials according to the fifteenth, sixteenth, and seventeenth embodiments. A V-ribbed belt including a joint was prepared. The rib pitch of the V-ribbed belts according to Examples 9 to 17 is 3.56 mm. Moreover, the stitch pitch at the time of sewing of the V-ribbed belt according to Examples 10 and 12 to 17 was set to 1 mm. The stitch pitch after molding was 1.4 mm. Moreover, the stitch pitches at the time of stitching in Example 9 and Example 11 were 0.3 mm and 1.5 mm, respectively, and the stitch pitches after molding were 0.4 mm and 2.0 mm, respectively. The sewing thread used for stitching the joints of the V-ribbed belts according to Examples 9 to 12 was a composite thread having polyester as a core thread and covered with cotton. Moreover, the material of the sewing thread used for stitching the joint portion of the V-ribbed belt according to Example 13 and Example 17 was nylon. Moreover, the material of the sewing thread used for the stitching | suture of the junction part of the V ribbed belt which concerns on Example 14, Example 15, and Example 16 was aramid. Moreover, Example 10 and Example 12 are the same joining aspects as Example 1.

(Durability test method)
In the durability test, each V-ribbed belt is wrapped around a multi-axis running test machine having a layout in which a driving pulley (Dr.) having a diameter of 60 mm and eight idler pulleys having a diameter of 50 mm are sequentially arranged as shown in FIG. It was. The endurance test condition is that a V-ribbed belt (3 ribs, 1500mm circumference) is hung on each pulley of the multi-axis test machine, the rotational speed of the drive pulley is 5200 rpm, the idler pulley is unloaded, and the belt tension Was 294N / 3 rib. The test temperature was 100 ° C. As a result of the durability test, Tables 2 to 7 show the number of rib portions where cracks occurred in the joint portion of the knitted fabric. Here, in Tables 2 to 7, “0” indicates that no crack is generated, “1” indicates that a crack is generated at a joint portion of one of the three rib portions, and “2” indicates that the three rib portions are not. Of these, cracks occurred at the joints of the two rib portions, and “3” indicates that cracks occurred at all three rib portions.

  In Example 1, Example 2, and Comparative Example, comparison was made between conventional ultrasonic welding and stitching with a sewing thread. In the comparative example in which the joint portions of the knitted fabric were joined by ultrasonic welding, cracks occurred in all the joint portions of the three rib portions in one hour after the start of running. On the other hand, in Example 1 and Example 2 in which the joint portion was stitched by zigzag stitching, the occurrence of cracks was suppressed, and the crack occurred only in one place even at 39 hours after the start of running. Thereby, when the joined part of the knitted fabric is stitched with the sewing thread, it is considered that the strength of the joined part can be improved as compared with the case where ultrasonic welding is adopted as the joining mode of the joined part of the knitted fabric.

  Next, in Example 3 (same as Example 1), Example 4 and Example 5, the overlap length was compared. Example 4 in which the overlap length is 2 mm as compared with Example 3 in which the overlap length is 0 mm (the state in which the knitted fabrics do not overlap each other but in a butted state: see FIG. 6A), and the overlap length In Example 5 having a length of 4 mm, generation of cracks was suppressed. The sewing width of Example 5 was 5 mm, and the sewing width was 1 mm larger than the overlap length. Thereby, an overlap portion where the knitted fabrics overlap each other is formed, and by stitching this overlap portion, compared to a case where a knitted fabric without an overlap portion where the knitted fabrics overlap each other is stitched (matching), It is considered that the strength of the joint can be increased. Further, it is considered that the overlap length can be increased by 4 mm rather than 2 mm.

  Next, in Example 6, Example 7, and Example 8, the comparison between the three-point zigzag stitching and the four-point zigzag stitching, and further, the adhesive between the overlapped knitted fabric and the knitted fabric The presence or absence was compared. In Examples 6 to 8 in which the stitching method was a three-point zigzag or a four-point zigzag, the effect of suppressing the occurrence of cracks was particularly high as compared with Example 5 in which the stitching method was a two-point zigzag. In Example 8, the rubber paste was applied between the knitted fabric and the knitted fabric in the overlap portion in order to increase the strength of the joint portion, but the rubber paste was not applied between the knitted fabric and the knitted fabric in the overlap portion. Compared to Example 7, on the contrary, it was a result in which cracks were likely to occur. Thereby, since the thickness of the overlap portion increases, it is considered better not to apply rubber glue between the knitted fabric and the knitted fabric of the overlap portion.

  Next, in Example 9, Example 10 (same as Example 1), and Example 11, the stitch pitches were compared. In Example 9 in which the stitch pitch was narrowed to 0.3 mm compared to Example 10 in which the stitch pitch was 1 mm, occurrence of cracks was suppressed. On the other hand, in Example 11 where the stitch pitch was as wide as 1.5 mm, more cracks occurred than in Example 10. Thereby, it turned out that the intensity | strength of a junction part increases by narrowing a stitch pitch.

  Next, in Example 12 (same as Example 1), Example 13, and Example 14, the suture materials were compared. Compared to Example 12 in which the suture material is a composite yarn of polyethylene and cotton, cracks are generated in Example 13 in which the suture material is nylon and Example 14 in which the suture material is aramid. It was suppressed. Thereby, it turned out that the intensity | strength of a junction part increases by making the material of a suture into nylon or an aramid. This is presumably because aramid excellent in wear resistance can maintain the strength of the joint, and nylon excellent in stretchability can suppress a decrease in the flexibility of the belt.

  Next, in Example 15, Example 16, and Example 17, the overlap length was set to 10 mm, and the suture location and the suture material were compared. In each of Examples 15 to 17, as in Example 7, the stitching method is 4-point zigzag stitching, and the stitching width is 5 mm. As compared with Example 7 in which the overlap length was 4 mm, in Examples 15 to 17 in which the overlap length was 10 mm, the occurrence of cracks was greatly suppressed. Further, in Example 15, as shown in FIG. 12 (a), the end of the overlap portion is stitched, and in Examples 16 and 17, the overlap is shown in FIG. 12 (b). The center of the part is stitched. From the comparison between Example 15 and Example 16, it is considered that the strength of the joint portion is further increased by stitching the center than the end of the overlap portion. Moreover, from Example 16 and Example 17, it was found that even when nylon or aramid was used as the suture material, the occurrence of cracks was sufficiently suppressed and the strength of the joint portion was further improved.

  As described above, the endurance test was performed on the reference example in which the joint portion was stitched with a flat seamer in contrast to the example in which the joint portion between the knitted fabrics was stitched with the staggered stitch. Here, the flat seamer is a four-needle sewing using a flat seam sewing machine, wherein a seam is formed by six threads, and the cloth to be sewn and the cloth are in a flat state. In the reference example, as shown in FIG. 13, the stretchability of the knitted fabric at the stitched portion was lowered, and the rib shape became abnormal. In other words, staggered stitching is an important stitching method in order not to reduce the stretchability of the knitted fabric, and other stitching methods cause defects in the rib shape of the V-ribbed belt, and are thus considered not applicable to the present invention.

DESCRIPTION OF SYMBOLS 1 V ribbed belt 2 Rib part 2A Tip part 3 Stretch layer 4 Compression layer 5 Core wire 6 Knitted fabric 60 Joining part 61 Sewing thread 62 Overlap part 10 Molded body 21 Drive pulley 22 Follow pulley 23 V-shaped groove 51 Flexible jacket 52 Inner mold 53 Outer mold 53a Rib mold SP Seam pitch SW Sewing width RP Rib pitch L Overlap length

Claims (17)

The friction transmission surface is covered with a knitted fabric having a joint,
The friction transmission belt, wherein the joint portion is sewn with a sewing thread.   The friction transmission belt according to claim 1, wherein stitching of the joint portion is staggered stitching.   The friction transmission belt according to claim 2, wherein the staggered stitches of the joint portion are a three-point zigzag or a four-point zigzag. In the joint portion, it has an overlap portion where the knitted fabrics overlap each other,
The friction transmission belt according to claim 1, wherein the overlap portion is stitched.   The friction transmission belt according to claim 4, wherein a length of the overlap portion in a belt circumferential direction is 2 mm or more and 20 mm or less.   6. The friction transmission belt according to claim 4, wherein a sewing width in the belt circumferential direction in the joint portion is 0.5 mm or more larger than a length in the belt circumferential direction of the overlap portion. The stitching of the joint is staggered,
The friction transmission belt according to any one of claims 1 to 6, wherein a stitch pitch, which is a distance between turning points in the belt width direction of the zigzag stitch, is 0.3 mm to 2 mm. A plurality of ribs extending in the belt circumferential direction are formed on the friction transmission surface,
The friction transmission belt according to any one of claims 1 to 7, wherein one or more needle drop points for the stitching are provided at a tip portion of the rib. A plurality of ribs extending in the belt circumferential direction are formed on the friction transmission surface,
The stitching of the joint is staggered,
The stitch pitch, which is a distance between turning points in the belt width direction of the staggered stitch, is 0.5 times or less of the rib pitch, which is the length of the rib in the belt width direction. The friction transmission belt according to any one of 8.   The friction transmission belt according to claim 1, wherein the sewing thread has a melting point or a softening point of 180 ° C. or higher.   The friction transmission belt according to any one of claims 1 to 10, wherein the sewing thread is a composite thread in which a synthetic fiber is used as a core thread and the periphery of the core thread is covered with a cellulosic fiber.   The friction transmission belt according to claim 1, wherein the sewing thread is made of nylon fiber.   The friction transmission belt according to claim 1, wherein the sewing thread is made of an aramid fiber.   A method for manufacturing a friction transmission belt, comprising a stitching step of sewing a joint portion of a knitted fabric covering a friction transmission surface with a sewing machine. In the suturing step,
The stitching is staggered;
The method for manufacturing a friction transmission belt according to claim 14, wherein a stitch pitch, which is a distance between turning points in the belt width direction of the staggered stitch, is 0.2 mm to 1.5 mm. In the suturing step,
Stitching of the knitted fabric covering the friction transmission surface formed with a plurality of ribs extending in the belt circumferential direction is staggered,
15. The stitch pitch, which is a distance between turning points in the belt width direction of the staggered stitch, is 0.35 times or less of the rib pitch, which is the length of the rib in the belt width direction. A method for producing a friction transmission belt as described in 1. In the joining portion, including an overlapping step of overlapping the knitted fabrics to form an overlapping portion,
The friction transmission belt according to any one of claims 14 to 16, wherein, in the suturing step, no adhesive is applied between the knitted fabric and the knitted fabric overlapped in the overlap portion. Production method.