JP2006009946A - Method for manufacturing transmission belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a transmission belt, capable of reducing noise in run of the belt, and reducing manufacturing manhours by uniformly attaching short fibers onto a transmission surface of the belt to be exposed in the surface. <P>SOLUTION: The transmission belt is composed by laminating a rubber layer containing core wires embedded along the belt length, and a compression rubber layer having a molded part adjoining the rubber layer, comprising rib parts extended along the belt length or cog parts provided at a prescribed interval along the belt length laminated with it. This method comprises a process of winding at least the core wires 48 around a flexible jacket surface 42 of an inner die 41, and laminating an unvulcanized rubber sleeve 24 having the short fibers 26 planted on a surface layer 23 that has been baked to be finished to be a belt mould 25, and a process of disposing the inner die 41 to an outer die 46 having die parts 45 engraved in an inner circumferential surface, and expanding the flexible jacket 42 to tightly apply the belt mold 25 to the die parts engraved in the outer die to be then vulcanized for forming a belt sleeve 51. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a transmission belt, and more particularly to a method for manufacturing a transmission belt in which short fibers are attached to a transmission surface of a rib portion to reduce noise during belt running and the number of manufacturing steps is reduced.

  2. Description of the Related Art Conventionally, there is known a power transmission belt in which an adhesive rubber layer having a core wire embedded in the belt longitudinal direction and a compressed rubber layer having a rib portion extending in the belt longitudinal direction and oriented short fibers in the width direction are laminated. Yes.

  This transmission belt is generally a vulcanized sleeve formed by laminating an adhesive rubber layer with a core wire embedded in the longitudinal direction of the belt and a flat compressed rubber layer forming a rib portion adjacent to the adhesive rubber layer. It is manufactured by attaching to a can, vulcanizing and forming a flat sleeve with no ribs, grinding this compressed rubber layer and scraping the ribs, and cutting them into rounds according to the number of ribs required. It was.

  However, a considerable amount of material loss has occurred by forming the rib portion by grinding the compressed rubber layer of the sleeve. Then, the method of forming a rib part, without grinding is proposed.

  As a method of improving this, a short fiber-containing rubber composition formed into a sheet by an expansion die is used for a transmission belt. For example, in Patent Document 1, a cylindrical rib rubber tube is extruded by an extruder equipped with an expansion die having a V rib portion molding groove at an outlet portion, and a V ribbed belt molded body is formed on a mold using a sheet obtained by cutting the rib rubber tube. Is molded, vulcanized, and the rib surface of the V-rib portion of the belt molded body is ground to expose the short fibers on the surface of the rib portion to produce a V-ribbed belt with reduced noise during running. ing.

  On the other hand, in addition to exposing the short fibers to the surface of the rib portion by such a grinding method, Patent Document 2 provides napping on at least one transmission portion contact surface of the power transmission side and the transmission surface by electrostatic flocking, and running A power transmission member with reduced noise is described.

  Further, Patent Document 3 discloses a transmission belt provided with a driving surface having a friction coefficient increased by mounting a flocked fabric on the belt surface.

JP-A-8-74936 Japanese Patent Laid-Open No. 9-14361 JP 2001-82549 A

  However, in the method of manufacturing a transmission belt having a rib portion, if it is directly attached to the surface of the rib portion by electrostatic flocking, even if sufficient flocking can be made near the entrance of the V-shaped rib groove, Development of a new manufacturing method has been desired due to the problem of difficulty in flocking. On the other hand, when a flocked fabric is used, an adhesive is applied to a fabric (substrate) such as a non-woven fabric, and a short fiber flock is mechanically and electrostatically attached to the fabric to produce a belt. In order to lap-join or butt-join the end portions of the flocked fabric, there is a possibility that peeling occurs from the joint portion of the fabric after forming the belt.

  The present invention pays attention to such a problem, and as a result of earnest research, the short belt is uniformly attached to the belt transmission surface and exposed to the surface, thereby reducing noise during belt running and reducing the number of manufacturing steps of the transmission belt. An object is to provide a manufacturing method.

In order to achieve the above object, the invention described in the claims of the present application includes a rubber layer in which a core wire is embedded along the longitudinal direction of the belt, and a rib portion extending in the longitudinal direction of the belt adjacent to the rubber layer or in the longitudinal direction of the belt. In a method for manufacturing a transmission belt in which a compression rubber layer having a mold portion made of cogs provided at predetermined intervals is laminated,
At least a core wire is wound around the inner flexible jacket surface, and an unvulcanized rubber sleeve in which short fibers are planted on the surface layer that has been baked is laminated to finish the belt molding.
The inner mold is arranged between an outer mold in which a mold part made of a rib mold or a cog mold is engraved on the inner peripheral surface, and the flexible jacket is expanded to engrave the belt molded body on the outer mold. This is a method for manufacturing a transmission belt that produces a belt sleeve that is vulcanized in close contact with the mold part. Further, when an adhesive is applied to the surface layer obtained by baking the rubber sleeve, the short fiber electrostatically implants the pile yarn. Including the case.

  According to the above configuration, the short fibers are implanted in the surface layer obtained by baking the rubber sleeve, and then vulcanized to suppress the rubber flow of the surface layer during vulcanization. Can be always exposed without being embedded in rubber, noise during belt running can be reduced, and since there is no conventional polishing step, the manufacturing process is reduced.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
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 short fiber dispersion

  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, such as 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.

  Then, the rubber layer 24 is baked by the heater 31 to form the surface layer 23 while the inner mold 41 is placed on the rotary table 30 and rotated. The surface layer 23 is heated at 350 to 500 ° C. for about 1 to 4 seconds to become a partially vulcanized skin layer, and the rubber flow is suppressed even after vulcanization, and the flocked yarn 26 is embedded in the rubber. There is no. The thickness of the surface layer 23 is about 0.1 to 1 mm.

Next, an adhesive is applied to the surface layer 23 of the rubber sleeve 24 while rotating the inner mold 41 by a known method such as a spray method or a dip method. As the adhesive, organic solvent capable of dissolving the rubber sheet 22 such as toluene, methyl ethyl ketone, rubber adhesive, RFL (resoricin-formaldedo-latex) adhesive, urethane emulsion, acrylic emulsion, vinyl acetate emulsion 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.
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.

  Although the thickness of an adhesive agent is not specifically limited, In order to make a short fiber favorable, it is about 0.05-1 mm, Preferably it is 0.05 mm-0.5 mm. However, in the present invention, it is not always necessary to apply the adhesive, but it is preferable to apply the adhesive.

  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 A pile of electrodeposited surfaces made of tetrafluoroethylene or the like is supplied, flying and pierced toward the surface layer 23 of the rubber sleeve 24 to provide a flocked yarn 26, and the rubber sleeve 24 after flocking is naturally or heated. dry.

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 is increased. 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.

  The rubber used for the adhesive rubber layer 103 is similar to the rubber compound of the compressed rubber layer 104 excluding short fibers. Of course, short fibers may be included.

  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 because the belt slip ratio can be kept low and the life of the belt is extended. 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 fabric fiber material, or a rubber material, more preferably 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.

  The embodiment described above can be implemented with the following modifications. First, in the above embodiment,

  In the said embodiment, although demonstrated by the type in which the compression rubber layer contains 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 from 10 to 60 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 becomes small 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.

  The transmission belt manufacturing method and the transmission belt of the present invention can be applied to transmission belts such as a V-ribbed belt and a low-edge V-belt that reduce noise during belt travel and reduce belt elongation.

It is sectional drawing which shows the state which has baked the rubber sleeve of the belt molded object with which the inner mold | type was mounted | worn. 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.

Explanation of symbols

22 Rubber material 23 Surface layer 24 Rubber sleeve 25 Belt molded body 26 Flocked thread 27 Molded part 41 Inner mold 42 Flexible jacket 45 Mold part 46 Outer mold 48 Core wire 51 Belt sleeve 100 V-ribbed belt 102 Core wire 102
103 Adhesive rubber layer 104 Compressed rubber layer 106 Rib part 107 Adhesive layer 108 Flocked short fiber 110 Inner layer 111 Surface layer

Claims (3)

Compression having a rubber layer with a core wire embedded in the longitudinal direction of the belt and a ribbed portion adjacent to the rubber layer extending in the longitudinal direction of the belt or a cog portion provided at predetermined intervals in the longitudinal direction of the belt In the manufacturing method of the transmission belt laminated with the rubber layer,
At least a core wire is wound around the inner flexible jacket surface, and an unvulcanized rubber sleeve in which short fibers are planted on the surface layer that has been baked is laminated to finish the belt molding.
The inner mold is arranged between an outer mold in which a mold part made of a rib mold or a cog mold is engraved on the inner peripheral surface, and the flexible jacket is expanded to engrave the belt molded body on the outer mold. Making a vulcanized belt sleeve in close contact with the mold part,
A method of manufacturing a power transmission belt characterized by the above.   The method for manufacturing a transmission belt according to claim 1, wherein an adhesive is applied to the surface layer obtained by baking the rubber sleeve. The method for manufacturing a transmission belt according to claim 1 or 2, wherein the short fibers are obtained by electrostatically filing pile yarns.

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