JP2008281153A - V-ribbed belt and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a V-ribbed belt a flocked layer of which enters not only a rib part surface layer but also the inside of rib rubber and does not disappear by abrasion in traveling for a short period of time and which does not generate sound after traveling for a long period of time, and its manufacturing method. <P>SOLUTION: This V-ribbed belt 1 made of unpolished rubber having a plurality of rib parts 106 extending in the belt longitudinal direction on an inner peripheral part is constituted so that flock stands on a surface of a contact part, the flock is buried inside of the rib parts 106 and becomes a flocked rubber layer 115 and its layer thickness is within a range of 35 μm to 200 μm from a rib surface. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a V-ribbed belt used for power transmission and the like and a manufacturing method thereof.

  A V-ribbed belt used for power transmission is generally formed by laminating a compression rubber layer having a plurality of ribs extending in parallel with the belt longitudinal direction and an adhesive rubber layer having a cord core embedded therein. And a stretched layer is disposed on the back side thereof. In the past, ribs were formed by grinding V-grooves on flat vulcanized sleeves as a method for manufacturing such V-ribbed belts. However, in recent years, the amount of material discarded has been reduced as much as possible and the manufacturing process has been simplified. There is a demand for construction methods.

  When grinding the V-groove on the vulcanized sleeve, the short fiber is exposed on the surface of the compressed rubber by grinding by blending the short fiber into the rubber sheet that becomes the compressed rubber layer, and the short fiber covers the V-rib surface. It was.

However, in the construction method that simplifies the manufacturing process, an unvulcanized stretched rubber sheet containing short fibers is wound on a flexible jacket mounted on a cylindrical drum, and a core wire is spun onto the unvulcanized stretched rubber sheet. Next, an unvulcanized compression rubber sheet is applied to form an endless unvulcanized belt sleeve, and then the jacket is expanded and the belt sleeve is pressed against an outer mold having a V-shaped protrusion and vulcanized. Has been proposed. (For example, see Patent Document 1)
JP 2005-125742 A

In addition, in order to flock the rib part surface, at least a core wire is wound around the inner flexible jacket surface, and an unvulcanized rubber sleeve in which short fibers are flocked is laminated on the surface layer that has been baked. Finishing the belt molded body, producing the above-mentioned inner mold, and vulcanizing the belt sleeve in close contact with the mold part in which the inner peripheral surface is engraved with a mold part consisting of a rib mold or a cog mold, and further baking the rubber sleeve An adhesive was applied to the layer, and electrostatic flocking was performed on the surface layer of the rubber sleeve using an electrostatic flocking machine. (For example, see Patent Document 2)
JP 2006-9946 A

  However, according to the method of Patent Document 2, since the adhesive is applied after the surface layer is baked, the adhesive does not penetrate into the rubber sleeve. Therefore, as shown in FIG. 121 also exists only on the surface of the rib part 123. When the belt was run, the flocked part was worn out in a short time, and the pronunciation in a short time was confirmed.

  The present invention relates to a V-ribbed belt in which the flocked layer penetrates not only into the rib surface layer but also into the rib rubber, the flocked layer does not disappear when worn for a short time, and no sound is generated even after a long time running. The purpose is to provide.

  The present invention relates to a V-ribbed belt made of unpolished rubber having a plurality of rib portions extending in the belt longitudinal direction on the inner peripheral portion, and the surface of the contact portion is raised to form a surface fiber layer, and further inside the rib portion. The V-ribbed belt has a flocked rubber layer formed by burying the flock and having a layer thickness within a range of 35 μm to 200 μm from the rib surface.

  According to the second aspect of the present invention, an unvulcanized belt sleeve formed by disposing a stretched layer on an inner mold, spinning a twisted cord, and then arranging a compressed rubber layer on the outer mold having a rib stamp is provided on the inner mold. In a manufacturing method of a V-ribbed belt for forming a vulcanized belt sleeve in which a rib is engraved by pressing from the peripheral side and vulcanizing, the method has a step of flocking the surface of the compressed rubber, and flocking the surface of the compressed rubber In the process, the adhesive diluted to a liquid and having a viscosity of 100 to 10000 mPa · s is sprayed on the surface of the compressed rubber, and then the short fibers are adhered, pressed from the inner peripheral side, vulcanized, and then the short fibers Is in a method for producing a V-ribbed belt that enters into the compressed rubber and forms a flocked rubber layer.

  Invention of Claim 3 exists in the manufacturing method of the V ribbed belt of Claim 2 whose thickness of the said flocked rubber layer is 35 micrometers-200 micrometers from the rib surface.

  According to the present invention, in the V-ribbed belt made of unpolished rubber having a plurality of rib portions extending in the belt longitudinal direction on the inner peripheral portion, the surface of the contact portion is raised to form a surface fiber layer, and the rib portion Because the V-ribbed belt has a flocked rubber layer buried inside, and the layer thickness is in the range of 35 μm to 200 μm from the rib surface, not only does not produce sound at the beginning of running, but also after running for a long time Since the flocks stay in the compressed rubber layer, there is an effect that the sound generation can be suppressed.

  According to the second aspect of the present invention, the unvulcanized belt sleeve formed by disposing the stretched layer on the inner mold, spinning the twisted cord, and then arranging the compressed rubber layer on the outer mold having the rib markings, In a method for manufacturing a V-ribbed belt for forming a vulcanized belt sleeve in which ribs are engraved by pressing from the inner peripheral side and vulcanizing, the method has a step of flocking the surface of the compressed rubber, and the flocking is applied to the surface of the compressed rubber. The applying step is performed by spraying an adhesive having a viscosity of ~ mPa · s diluted with a liquid onto the surface of the compressed rubber, and then attaching short fibers, pressing from the inner periphery side, vulcanizing the rubber, and then the short fibers Is a manufacturing method of a V-ribbed belt that enters into the compressed rubber to form a flocked rubber layer, and when the compressed rubber is pressed into the outer V groove, the rubber is mixed with an adhesive containing short fibers, Flocking rubber Forming a, there is an effect that can be up to the ribs inside not the rib portion surfaces only Komu putting short fibers.

  According to invention of Claim 3, since the thickness of the said flocked rubber layer is 35 micrometers-200 micrometers from a rib surface, since it is a manufacturing method of the V ribbed belt of Claim 2, the manufactured belt is driving | running | working initial stage. In addition to not producing sound, the flocked hair stays in the compressed rubber layer even after running for a long time, so that the sound production can be suppressed.

  Hereinafter, the V-ribbed belt of the present invention and the manufacturing method thereof will be described in detail. In the present invention, a rubber material in which short fibers forming a compressed rubber layer are oriented in the width direction is produced. As a production method thereof, there are an extrusion method and a rolling method using a calendar. Of course, a rubber material that does not contain short fibers can also be used.

  In the following, as an example, when a sheet-like rubber material in which fibers are oriented in the width direction is produced by an extrusion method, 10 to 40 parts by mass of short fibers are added to 100 parts by mass of the polymer in advance by an open roll. After kneading, the kneaded master batch is discharged once and cooled to 20 to 50 ° C. to prevent rubber scorching.

  When 1 to 10 parts by mass of a softening agent is added, the familiarity between the short fibers and the rubber is improved, and the dispersion into the rubber is improved. In addition, the short fibers themselves are prevented from being entangled and becoming cottony. In other words, the softener penetrates into the short fibers and acts as a lubricant to loosen the entanglement between the elementary fibers, prevents the short fibers from becoming cottony, and the familiarity between the short fibers and the rubber. Improves the dispersion of short fibers.

  Subsequently, after the master batch is kneaded with an extrusion screw of a cylinder in an extruder, the temperature is usually adjusted to 40 to 100 ° C., the rubber mixed with short fibers is smoothly flowed to the rubber passage made of the environment expansion die, and the rubber While passing through the passage, it is extruded into a cylindrical molded body in which short fibers are oriented in the circumferential direction. Thereafter, the cylindrical molded body has a thickness of 1 to 10 mm in which the short fibers are uniformly oriented in the circumferential direction from the inner layer to the outer layer, and is cut into one sheet by a cutting means into a sheet-like rubber material, Subsequently, the rubber material is cut at a predetermined interval.

  The rubber materials used here include natural rubber, butyl rubber, styrene-butadiene rubber, chloroprene rubber, ethylene-propylene rubber, alkylated chlorosulfonated polyethylene, hydrogenated nitrile rubber, hydrogenated nitrile rubber and unsaturated carboxylic acid. A mixed polymer with an acid metal salt, a rubber material such as ethylene-α-olefin elastomer made of ethylene-propylene rubber (EPR) or ethylene-propylene-diene monomer (EPDM), or a mixture thereof is used. Examples of diene monomers include dicyclopentadiene, methylene norbornene, ethylidene norbornene, 1,4-hexadiene, cyclooctadiene, and the like.

  The rubber material is made of fibers such as aramid fiber, polyamide fiber, polyester fiber, and cotton, and the length of the fiber varies depending on the type of fiber, but short fibers of about 1 to 10 mm are used, for example, aramid fiber. About 3 to 5 mm, polyamide fibers, polyester fibers, and cotton are about 5 to 10 mm. The addition amount is 10 to 40 parts by mass with respect to 100 parts by mass of rubber.

  Furthermore, a softener, a reinforcing agent made of carbon black, a filler, an anti-aging agent, a vulcanization accelerator, a vulcanizing agent, and the like are added to the rubber material.

  Examples of the softening agent include general rubber plasticizers, for example, phthalates such as dibutyl phthalate (DBP) and dioctyl phthalate (DOP), adipates such as dioctyl adipate (DOA), and dioctyl sebacate (DOS). Sebacates, phosphates such as tricresyl phosphate, etc., or general petroleum softeners are included.

  Subsequently, as shown in FIG. 1, a reinforcing cloth 47, an adhesive rubber 49, and a cord 48 made of a cord are sequentially wound around the outer peripheral surface of a vulcanized rubber flexible jacket 42 attached to the inner mold 41. Then, a sheet-like rubber material 22 in which short fibers are oriented is wound, lap jointed, and an unvulcanized rubber sleeve 24 is laminated to produce a belt molded body 25.

Next, an adhesive is applied to the surface layer 23 of the rubber sleeve 24 by a known method such as a spray method or a dip method while the inner die 41 is placed on the rotary table 30 and rotated. Adhesives include organic solvents that can dissolve rubber material 22 such as toluene and methyl ethyl ketone, rubber adhesives, RFL (resoricin-formaldedo-latex) adhesives, urethane emulsions, acrylic emulsions, vinyl acetate emulsions. And styrene emulsions. The RFL liquid is obtained by mixing an initial condensate of resorcin and formaldehyde in a latex. Examples of the latex used here include chloroprene, styrene-butadiene-vinylpyridine terpolymer, hydrogenated nitrile, NBR, ethylene. This is an α-olefin-diene copolymer rubber latex. An isocyanate compound can also be added to the RFL solution. Here, the density | concentration of a diluent, latex, etc. is adjusted so that the viscosity of an adhesive agent may be 100-10000 mPa * s. Here, if the viscosity of the adhesive is less than 100 mPa · s, there is a problem that the hair droops and uneven hair transplantation occurs.
Note that before the adhesive is applied, the surface of the rubber sleeve 24 may be subjected to a pretreatment such as a cleaning treatment such as alcohol wiping or a primer treatment.
The adhesive is preferably applied very thinly.

  Subsequently, electrostatic flocking is performed on the surface layer 23 of the rubber sleeve 24 using a known electrostatic flocking machine 32 as shown in FIG. For the flocking treatment, the inner mold 41 is grounded, and an electric field is formed by applying a voltage to the electrode of the electrostatic flocking machine. In this electric field, rayon, cotton, polyester, nylon, aramid, vinylon, carbon fiber, poly The piled yarn 26 is provided by supplying a pile having a surface made of tetrafluoroethylene or the like electrodeposited, flying it, and piercing it toward the surface layer 23 of the rubber sleeve 24.

The length of the pile is preferably 0.1 to 5.0 mm, and the aspect ratio (length Lmm / thickness diameter Dmm is 30 to 300. Further, the density of the flocked yarn contributes to the friction coefficient and sound during running. The speed of the belt is about 10,000 to 500,000 / cm ^2, which is a recent transmission belt used today.

  Next, as shown in FIG. 3, the inner mold 41 equipped with the above-mentioned flocked rubber sleeve 24 is placed on the base with a certain gap inside the outer mold 46. Since the inner mold 41 is moved from another molding process, the medium distribution port A and the medium feeding / discharging path B are separated. After the inner mold 41 is placed on the base, the medium distribution port A is Connect to the pipe with joint J.

  The medium feeder is operated to feed high-pressure air or high-pressure steam into the flexible jacket 42 through the medium inlet / outlet passage B and the medium circulation port A. Since the upper and lower portions of the flexible jacket 42 are hermetically fixed on the inner mold 41, air is filled between the inner surface of the flexible jacket 42 and the outer surface of the inner mold 41. It gradually expands. Then, the belt molded body 25 is uniformly expanded in the radial direction, and is in close contact with the mold portion 45 of the outer mold 46 heated to 100 to 180 ° C. with a heater or high-temperature steam to vulcanize the belt sleeve 51.

  After vulcanization, the flexible jacket 42 is contracted as shown in FIG. 4 and the inner die 41 is removed from the outer die 46, and then the vulcanized belt sleeve 51 attached to the outer die 46 is removed. On the surface of the die-attached portion 27 of the vulcanized belt sleeve 51, the short fibers (planted yarn 26) are fixed to the surface layer 23 of the die-attached portion 27, raised at various angles, and exposed.

  Furthermore, while the vulcanized belt sleeve 51 is inserted into another one- or two-axis drum and rotated, it is cut into a predetermined width in the circumferential direction, taken out from the drum and reversed, so that the circumference is constant. A V-ribbed belt 1 in which V-shaped ribs were accurately formed was obtained. When the outer mold 46 is a split mold, the unvulcanized sleeve can be easily inserted and the vulcanized sleeve can be easily removed, and the split surface can function as a kind of air vent to further enhance the V-shaped rib. It can be formed accurately.

  FIG. 5 is a cross-sectional view of the obtained V-ribbed belt. The V-ribbed belt 100 has a cord 102 made of a cord having high strength and low elongation embedded in an adhesive rubber layer 103, and has a compression rubber layer 104 as an elastic body layer below the cord. The compressed rubber layer 104 is provided with a plurality of rib portions 106 (molded portions) having a substantially triangular cross section extending in the longitudinal direction of the belt, and the short fibers 109 are arranged in a wave shape on the inner layer 110 of the rib portion, whereby the lateral pressure resistance of the belt. Further, the flocked short fibers 108 are fixedly exposed on the surface layer 111 of the rib portion. The surface layer 111 includes an adhesive layer 107. Further, by mixing the adhesive and the vulcanized rubber, the flocked rubber layer is formed with a certain thickness continuously with the surface of the rib portion. As a result, the rib side surface forms a raised surface fiber layer 113 and a flocked rubber layer 115 in which flocks are buried inside the rib portion (FIG. 6). The thickness of the flocked rubber layer 115 is preferably 35 μm to 200 μm from the rib surface.

  As the core wire 102, a polyester fiber, an aramid fiber, and a glass fiber are used. Among them, the total number of deniers obtained by twisting together polyester fiber filaments having ethylene-2,6-naphthalate as a main constituent unit is 4,000 to 8, A cord subjected to adhesion treatment of 000 is preferable in order to keep the belt slip ratio low and extend the belt life. Further, the core wire 102 is subjected to an adhesion treatment for the purpose of improving the adhesion to rubber. As such an adhesion treatment, it is common to immerse the fiber in a resorcin-formalin-latex (RFL) solution and then heat-dry to form a uniform adhesion layer on the surface. However, the present invention is not limited to this, and there is also a method of performing a pretreatment with an epoxy or isocyanate compound and then treating with an RFL solution.

  The core wire 102 can be finished into a belt having a high modulus by setting the spinning pitch, that is, the winding pitch of the core wire to 0.9 to 1.3 mm. If it is less than 0.9 mm, the cord cannot ride on the adjacent cord and cannot be wound, while if it exceeds 1.3 mm, the modulus of the belt gradually decreases.

  The back reinforcing material 105 is selected from a woven fabric, a knitted fabric, a non-woven fiber material, or a rubber material, and a more preferable one is a non-woven fabric. Examples of the constituent fiber material include natural fibers such as cotton, hemp, and rayon, and organic fibers such as polyamide, polyester, polyethylene, polyurethane, polystyrene, polyfluoroethylene, polyacryl, polyvinyl alcohol, wholly aromatic polyester, and aramid. Can be mentioned. The above canvas is immersed in a resorcin-formalin-latex liquid (RFL liquid) according to a known technique, then subjected to friction by rubbing unvulcanized rubber against the back reinforcing material 105, and soaked in rubber after being immersed in the RFL liquid. Immerse in.

  In such a V-ribbed belt, the short fibers 108 uniformly attached to the surface of the rib portion reduce noise during belt running, and further prevent cracks from occurring on the surface of the rib portion. Furthermore, even if the rib portion wears after running for a long time, the short fibers in the flocked rubber layer are continuously exposed, and thus the noise can be reduced for a long time.

  The embodiment described above can be implemented with the following modifications. First, in the said embodiment, although the compression rubber layer demonstrated by the type containing the short fiber oriented in the width direction, the compression rubber layer which does not contain a short fiber for cost reduction may be sufficient. Even for compressed rubber layers that do not contain short fibers, sleeves are laminated and vulcanized while maintaining the alignment of the core wires while maintaining the flow of the compressed rubber layer along the ribs. Can do.

  Instead of short fibers, a solid lubricant can be blended in the compressed rubber layer. This solid lubricant is selected from hexagonal or scaly graphite, diverted molybdenum, and polytetrafluoroethylene, and the amount added is 10 to 100 parts by weight, preferably 100 parts by weight of raw rubber. Is less than 10 parts by mass, and when the amount is less than 10 parts by mass, if the amount exceeds 10 parts by mass, the elongation of the rubber properties is reduced and the belt life is shortened.

  About the back reinforcement material of a transmission belt, it can also be set as the transmission belt of the type which does not laminate | stack a back reinforcement material depending on the case.

  Moreover, a low edge cog belt can also be shape | molded with the manufacturing method of the power transmission belt using the type | mold apparatus mentioned above. This belt includes a core wire embedded in a spiral shape in the longitudinal direction of the belt in an adhesive rubber layer, a stretched rubber layer laminated on the upper side (belt outer peripheral side) of the core wire, and a lower side (belt) of the core wire It is composed of a compressed rubber layer laminated on the inner peripheral side, and the compressed rubber layer has cogs having alternating concave and convex portions provided at predetermined intervals. Reinforcing cloth is provided on the back surface of the stretch rubber layer and the cog portion surface of the compression rubber layer.

  When molding this belt, the outer mold 46 may be provided with a mold portion 45 corresponding to a cog mold extending in the longitudinal direction of the outer mold 46 at a predetermined interval along the inner peripheral direction of the main body. The structure of the other mold devices remains unchanged.

Hereinafter, the present invention will be described in more detail with reference to examples.
A V-ribbed belt was prepared using the rubber composition having the composition shown in Table 1. The V-ribbed belt manufactured in this example has a configuration in which a compression portion in which short fibers are oriented in the belt width direction is provided as an extension portion, and is embedded between an extension portion and a compression portion made of a polyester fiber rope. It should be noted that the compression part has three ribs arranged in the belt longitudinal direction. Here, the stretched portion and the compressed portion were prepared from the rubber composition shown in Table 1, kneaded with a Banbury mixer, and then rolled with a calendar roll. The rib portion surface was raised with polyamide fibers, and in the cross section of the belt rib portion, a flocked rubber layer was formed from the rib portion surface, and the thickness thereof was about 35 μm.

The belt is manufactured by sequentially winding a cord made of a reinforcing fabric, an adhesive rubber, and a cord around an outer peripheral surface of a vulcanized rubber flexible jacket mounted on an inner mold, and then orienting short fibers. A belt-shaped body was produced by winding a rubber material and laminating an unvulcanized rubber sleeve as a lap joint. The rubber sheet was a rubber compound shown in Table 1, and the core was a polyester fiber cord subjected to adhesion treatment.

Next, an adhesive was applied to the surface layer of the rubber sleeve by spraying while the inner mold was placed on a rotary table and rotated. As an adhesive, an acrylic resin-based adhesive (trade name: Diabond, manufactured by Nogawa Chemical Co., Ltd.) is used, diluted with water as a diluent, and the viscosity of the diluted adhesive is 100 to 10,000 mPa · s. It was adjusted to become.
Next, an electric field is formed by applying a voltage to the electrode of the electrostatic flocking machine with the inner mold 41 as a ground, and a pile obtained by electrodeposition treatment of the surface made of polyamide fiber is supplied into the electric field, and then it is allowed to fly. It pierced toward the surface layer of the rubber sleeve. At this time, the pile diffused over the entire circumference of the rubber sleeve.

  Next, the inner mold equipped with the above-mentioned flocked rubber sleeve was placed on the base with a certain gap inside the outer mold. Then, the flexible jacket is expanded, the belt molded body is uniformly expanded in the radial direction, and is closely vulcanized with a high temperature steam heated to 100 to 180 ° C. to vulcanize to produce a belt sleeve. did.

  After vulcanization, the flexible jacket is shrunk, the inner mold is removed from the outer mold, and the vulcanized belt sleeve attached to the outer mold is removed. On the surface of the mold part of the vulcanized belt sleeve, short fibers (flocked yarn) are fixed to the surface layer of the mold part, raised at various angles, and exposed.

  Furthermore, while the vulcanized belt sleeve 51 is inserted into another one- or two-axis drum and rotated, it is cut into a predetermined width in the circumferential direction, taken out from the drum and reversed, so that the circumference is constant. A V-ribbed belt 1 in which V-shaped ribs were accurately formed was obtained. When the outer mold 46 is a split mold, the unvulcanized sleeve can be easily inserted and the vulcanized sleeve can be easily removed, and the split surface can function as a kind of air vent to further enhance the V-shaped rib. It can be formed accurately. Looking at the cross section of the obtained belt, the flocked fiber layer is embedded in the rubber, and it can be confirmed that the flocked fiber layer is present on the rib part surface and the rib inner surface. It was confirmed that it entered into the range of 35 μm from the rib surface.

  The obtained V-ribbed belt was mounted on an actual vehicle and traveled, and the friction coefficient for each travel distance was measured with a testing machine having the layout of FIG. The result is shown in FIG.

Next, as a comparative example, the outermost rubber sleeve to be attached was the same as that of the example, but an adhesive that was not diluted was used. The method of electrostatic flocking was the same as in the examples. The cross section of the obtained belt had a flocked fiber layer only on the rib surface, and did not enter the rib inner surface. The obtained V-ribbed belt was run in the same manner as in the example, and the friction coefficient for each running distance was measured with a testing machine having the layout shown in the figure. The result is shown in FIG.

  According to FIG.7 and FIG.8, although the Example hardly shows the change of the friction coefficient by a travel distance, the change of a friction coefficient is large as a travel distance increases in the comparative example. Therefore, it can be seen that the sound generation and power transmission performance are different after the vehicle has traveled to some extent from the initial time of travel.

  The present invention can be applied to a V-ribbed belt with reduced noise during belt running.

It is a longitudinal cross-sectional view of the state which shape | molds a preforming body. It is a figure which shows the state which planted the short fiber in the surface layer of the rubber sleeve. It is sectional drawing of the state which is vulcanizing the belt molded object. It is sectional drawing of the state after vulcanizing a belt molded object. It is sectional drawing of the V-ribbed belt obtained with the manufacturing method of this invention. It is sectional drawing of the rib part of the V-ribbed belt of this invention. It is the layout of the testing machine which measured the friction coefficient of the Example and the comparative example. It is a measurement result of the friction coefficient of an Example. It is a measurement result of the friction coefficient of a comparative example. It is sectional drawing of the rib part of the conventional V-ribbed belt.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 V ribbed belt 22 Rubber material 23 Surface layer 24 Unvulcanized rubber sleeve 26 Flocked thread 30 Rotary table 32 Electrostatic flocking machine 41 Inner mold 42 Flexible jacket 45 Mold part 46 Outer mold 47 Reinforcement cloth 48 Core wire 49 Adhesive rubber 51 Belt Sleeve 100 V-ribbed Belt 102 Core Wire 103 Adhesive Rubber Layer 104 Compressed Rubber Layer 105 Back Reinforcement Material 106 Rib 107 Adhesive Layer 108 Flocked Short Fiber 109 Short Fiber 110 Inner Layer 111 Surface Layer 113 Surface Fiber Layer 115 Flocked Rubber Layer

Claims (3)

  In a V-ribbed belt made of unpolished rubber having a plurality of ribs extending in the longitudinal direction of the belt on the inner peripheral part, the surface of the contact part is raised to form a surface fiber layer, and the flocking is buried inside the rib part The V-ribbed belt is characterized in that the flocked rubber layer has a layer thickness within the range of 35 μm to 200 μm from the rib surface. After placing the stretch layer on the inner mold and spinning the twisted yarn cord, the unvulcanized belt sleeve formed by arranging the compressed rubber layer is vulcanized by pressing it from the inner circumference side to the outer mold having rib markings. In the method of manufacturing a V-ribbed belt for forming a vulcanized belt sleeve having ribs engraved thereon,
A step of flocking the surface of the compressed rubber, and the step of flocking the surface of the compressed rubber is performed by spraying the surface of the compressed rubber with an adhesive diluted with a liquid and having a viscosity of 100 to 10000 mPa · s. The V-ribbed belt manufacturing method is characterized in that after the rubber is vulcanized by adhering to the inner peripheral side and vulcanizing the rubber, the short fibers enter the compressed rubber to form a flocked rubber layer.   The method for producing a V-ribbed belt according to claim 2, wherein the flocked rubber layer has a thickness of 35 μm to 200 μm from the rib surface.

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