JP2004255619A - Transmission belt manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmission belt manufacturing method of which the noise at the time of belt traveling is reduced by uniformly bonding short fibers to the transmission surfaces of rib parts. <P>SOLUTION: In the transmission belt manufacturing method, a rubber sheet 20 is interposed between an outer mold 46, which have rib molds 45 carved in its inner peripheral surface and have short fibers 7 bonded to its inner peripheral surface coated with an adhesive 9, and an inner mold 41 having a flexible jacket 42 mounted on its outer peripheral surface and closely brought into contact with the rib molds 45 carved in the outer mold 46 by expanding the flexible jacket 42 to form an unvulcanized premolded body 21. At least a core wire 48 is wound around the surface of the flexible jacket 42 of the inner mold separated from the outer mold and, after the inner mold 41 is again installed in the outer mold 46, the core wire 48 and the premolded body 21 are integrally vulcanized by expanding the flexible jacket 42 to manufacture a vulcanized belt sleeve 51b having the short fibers 7 bonded to the surfaces of the rib parts thereof. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing a power transmission belt, and more particularly to a method for manufacturing a power transmission belt in which short fibers are attached to a power transmission surface of a rib portion to reduce noise during belt running.
[0002]
[Prior art]
In a conventional method of manufacturing a power transmission belt, a belt formed body obtained by winding a rolled rubber sheet containing short fibers around a forming drum so that the short fibers are oriented in the width direction is vulcanized, and a belt sleeve is formed by a glider wheel. A plurality of ribs were ground on the surface, and short fibers were protruded from the surface of the rib to produce a belt with reduced running noise.
[0003]
On the other hand, besides exposing the short fibers to the surface of the rib portion by such a grinding method, Japanese Patent Application Laid-Open Publication No. H11-157572 discloses a method in which a brush is provided on at least one of the power transmission side and the transmission surface in contact with the transmission portion by electrostatic flocking. A power transmission member with reduced noise is described.
[0004]
Patent Document 2 discloses a power transmission belt in which a flocked fabric is mounted on the belt surface and a drive surface having an increased friction coefficient is provided.
[0005]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 9-14361 [Patent Document 2]
JP 2001-82549 A
[Problems to be solved by the invention]
However, according to the method of manufacturing a power transmission belt having a rib portion, if the surface of the rib portion is directly raised by electrostatic flocking, sufficient flocking can be performed near the entrance of the V-shaped rib groove, but flocking at a deep portion in the rib groove. Therefore, there is a problem that it is difficult to perform the development, and development of a new manufacturing method has been desired. On the other hand, in the case of using a flocked fabric, an adhesive is applied to a fabric (substrate) such as a nonwoven fabric, and a short-fiber floc is mechanically and electrostatically adhered onto the fabric to produce a belt. Since the end portions of the flocked fabric are lap-joined or butt-joined, there is a possibility that peeling will occur from the joint portion of the fabric after the belt is formed.
[0007]
The present invention focuses on such a problem, and as a result of intensive studies, it is an object of the present invention to provide a method of manufacturing a power transmission belt in which short fibers are uniformly adhered to a power transmission surface of a rib portion to reduce noise during belt running.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, an invention according to claim 1 of the present application is directed to a power transmission belt having a rubber layer in which a core wire is embedded along the belt longitudinal direction, and a rib portion extending in the belt longitudinal direction adjacent to the rubber layer. In the manufacturing method of
The short fibers are attached via an adhesive applied to the inner peripheral surface of the outer mold in which a rib mold is engraved on the inner peripheral surface,
A rubber sheet is interposed between the outer mold having the short fibers attached to the inner peripheral surface and the inner mold having a flexible jacket attached to the outer peripheral surface,
The flexible jacket is inflated and the rubber sheet is brought into close contact with a stamped rib mold of an outer mold to produce an unvulcanized preform,
At least a core wire is wound around the flexible jacket surface of the inner mold detached from the outer mold, and the inner mold is placed in the outer mold again, and the flexible jacket is expanded to attach the core wire to the outer mold. There is provided a method for manufacturing a power transmission belt, in which a vulcanized belt sleeve in which short fibers are adhered to the surface of a rib portion by vulcanizing integrally with a molded body is produced.
[0009]
According to this manufacturing method, the rib portion of the vulcanized belt sleeve can be accurately manufactured by molding, and the short fiber-mixed adhesive adhered to the inner peripheral surface of the outer die is cured at the time of vulcanization to cure the vulcanized belt sleeve. It can be transferred to the rib surface and the short fibers can be attached to the rib surface.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
In the present invention, a single rubber sheet in which short fibers are oriented in the width direction is used, and as a manufacturing method, there are an extrusion method and a calendering rolling method. Of course, a rubber sheet containing no short fibers can also be used. In the case of producing a rubber sheet in which fibers are oriented by an extrusion method, 10 to 40 parts by mass of short fibers are previously added to 100 parts by mass of a polymer by an open roll and kneaded, and then the kneaded master batch is released once. This is cooled to 20-50 ° C to prevent rubber scorch.
[0011]
When 1 to 10 parts by mass of a softening agent is added, the short fibers and the rubber are well blended, and not only the dispersion in the rubber is improved, but also the short fibers themselves are prevented from becoming entangled and becoming floc. 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 cotton-like, and reduces the familiarity between the short fibers and the rubber. It becomes better and the dispersion of short fibers becomes better.
Subsequently, it is possible to finish the short fibers into one rubber sheet in which the short fibers are oriented in the width direction by using an extruder in which an extension die is attached to an extruder. Although not shown here, after kneading the master batch with the extrusion screw of the cylinder in the extruder, the short fiber-containing rubber is located between the inner dies located at the position facing the cylinder and on the same center axis. A cylindrical molded body in which flow is not hindered by the rubber passage and smoothly flows into the rubber passage of the expansion die without changing the flow direction, and the short fibers are circumferentially oriented while passing through the rubber passage. Extrusion molding.
[0013]
Thereafter, the cylindrical body without a weld line, which was continuously extruded and formed, had a thickness of 1 to 10 mm in which short fibers were uniformly oriented in the circumferential direction from the inner layer to the outer layer, and was incised at one location by a cutting means. Then, one short fiber oriented rubber sheet is formed while cutting the rubber sheet at a predetermined interval.
[0014]
As the rubber used here, natural rubber, butyl rubber, styrene-butadiene rubber, chloroprene rubber, ethylene-propylene rubber, alkylated chlorosulfonated polyethylene, hydrogenated nitrile rubber, hydrogenated nitrile rubber and unsaturated metal salt of carboxylic acid , A rubber material such as an ethylene-α-olefin elastomer composed of ethylene-propylene rubber (EPR) or ethylene-propylene-diene monomer (EPDM) alone, or a mixture thereof. Examples of the diene monomer include dicyclopentadiene, methylene norbornene, ethylidene norbornene, 1,4-hexadiene, cyclooctadiene, and the like.
[0015]
The rubber 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 the fiber. Short fibers of about 1 to 10 mm are used. Polyamide fiber, polyester fiber, and cotton having a size of about 5 to 10 mm are used. The addition amount is 10 to 40 parts by mass based on 100 parts by mass of the rubber.
[0016]
Further, a softener, a reinforcing agent composed of carbon black, a filler, an antioxidant, a vulcanization accelerator, a vulcanizing agent, and the like are added to the rubber.
[0017]
Examples of the softener include plasticizers for general rubbers, for example, phthalates such as dibutyl phthalate (DBP) and dioctyl phthalate (DOP), adipates such as dioctyl adipate (DOA), and dioctyl sebacate (DOS). It includes sebacate-based phosphates such as tricresyl phosphate, and general petroleum-based softeners.
[0018]
Next, as shown in FIG. 1, a release agent such as silicone oil is applied to the surface of the protruding rib mold 45 engraved on the inner peripheral surface of the cylindrical outer mold 46 at regular intervals, and then the short fibers 7 are removed. The mixed uncured adhesive 9 is sprayed by the spray 10 to form the short fiber mixed coating film 8 having a thickness of about 0.5 to 3 mm. At this time, the temperature of the inner peripheral surface of the outer mold 46 is room temperature, preferably 20 to 100 ° C., which is a temperature at which the adhesive of the short fiber mixed coating film 8 does not cure. The temperature of the outer mold 46 is adjusted by passing a heat medium such as steam or a coolant such as water into a space (not shown) provided in the main body.
[0019]
As the adhesive 9 mixed with the short fibers 7 used here, an RFL (resoricin-formaldehyde-latex) adhesive, a vinyl acetate emulsion, a styrene emulsion, and an unvulcanized rubber are dissolved in a solvent such as toluene and xylene. Rubber glue, organic solvent-based adhesives and the like. As a preferable adhesive, an RFL liquid or a rubber paste is preferable, and a thermosetting reaction occurs simultaneously with vulcanization molding. The RFL solution is obtained by mixing a latex with an initial condensate of resorcinol and formaldehyde, and the latex used here is chloroprene, styrene / butadiene / vinylpyridine terpolymer, hydrogenated nitrile, NBR, ethylene. α-olefin-diene copolymer. Further, an isocyanate compound can be added to the RFL liquid.
[0020]
In the method of spraying short fibers, a short fiber made of polyester, nylon, aramid, vinylon, carbon fiber, polytetrafluoroethylene, cotton, or the like is used. A short fiber mixed coating film 8 is formed on the surface of the substrate 45.
[0021]
The length of the short fibers is preferably 0.1 to 5.0 mm, and the aspect ratio (length Lmm / thickness diameter Dmm is 30 to 300. The fiber density contributes to the coefficient of friction and the sound during running. , Which is close to the power transmission belt used today, and is 10,000 to 500,000 belts / cm ² .
[0022]
As another method, after spraying an adhesive that does not mix short fibers onto the surface of the protruding rib mold 45 provided on the inner peripheral surface of the cylindrical outer mold 46, only the short fibers are sprayed by a spray coating device. Can also be attached.
[0023]
As another method, after spraying only a solvent such as toluene or xylene as an adhesive on the surface of the protruding rib mold 45 provided on the inner peripheral surface of the cylindrical outer mold 46, only the short fibers are sprayed with a spray coating device. Can be applied by spraying.
[0024]
As another method, an adhesive is sprayed on the surface of the protruding rib mold 45 provided on the inner peripheral surface of the cylindrical outer mold 46, and then the outer mold 46 is charged and the short fibers are blown off by lines of electric force. Hair can also be planted.
[0025]
Subsequently, as shown in FIG. 2, the inner mold 41 in which the adhesive rubber sheet 16 and the rubber sheet 20 forming the compression rubber layer are sequentially wound on the surface of a flexible jacket 42 provided on the outer peripheral surface of the inner mold 41 is used. Is placed on the base so as to form a constant gap inside the outer mold 46. Since the inner mold 41 is moved from another molding step, the medium circulation port A and the medium feeding / discharging path B are separated from each other. After the inner mold 41 is placed on the base, the medium circulation port A is Connect to the pipe at joint J.
[0026]
The medium feeder is operated to feed the inside of the flexible jacket 42 through the medium feed / discharge path B for high-pressure air or the like and the medium flow port A. Since the upper and lower portions of the flexible jacket 42 are hermetically sealed on the inner mold 41, the space between the inner surface of the flexible jacket 42 and the outer surface of the inner mold 41 is filled with air. It expands gradually. Then, the short fiber oriented rubber sheet 20 mounted on the outer peripheral surface is uniformly expanded in the radial direction, and the rib mold 45 of the outer mold 46 heated to 100 to 160 ° C. with a heater or high-temperature steam is used for 30 to 120 seconds. Make contact.
[0027]
At this time, the rubber sheet 20 is pressed against the rib mold 45 of the outer mold 46 by the expansion pressing force of the flexible jacket 42, and the unvulcanized preliminary molding having a plurality of V-shaped protrusions on the surface as shown in FIG. The body 21 is formed. The preform 21 adheres to the short-fiber-mixed coating film 8, but is not integrally bonded to the preform 21 at this stage because the short-fiber-mixed coating film 8 is uncured.
[0028]
Thereafter, the valve is switched to the vacuum pump to exhaust the air filled in the flexible jacket 42, and then the flexible jacket 42 is contracted and returned to the original position shown in FIG. 2 by suction. .
[0029]
Then, the inner die 41 is pulled out from the outer die 46, and a core 48 made of a reinforcing cloth 47 and a cord is sequentially wound around the outer peripheral surface of the flexible jacket 42 of the inner die 41. Thereafter, as shown in FIG. 4, the inner mold 41 is placed in the outer mold 46, and then the flexible jacket 42 is expanded as shown in FIG. 5, and the reinforcing cloth 47 and the core wire 48 are evenly distributed in the radial direction. The belt sleeve 51 is produced by expanding and intimately and integrally vulcanizing the preform 21 attached to the rib mold 45 of the outer mold 46 heated to 100 to 180 ° C. by a heater or high-temperature steam. By molding the unvulcanized preformed body 21 as in the above-described manufacturing method, the amount of expansion of the core wire 48 due to expansion of the flexible jacket 42 during molding can be suppressed, and the core wire 48 can be arranged flat. A V-ribbed belt having excellent stability can be manufactured.
At the same time, the short fiber mixed coating film 8 hardens and moves from the surface of the rib mold 45 to the preformed body 21 side, and the short fibers adhere firmly to the preformed body 21.
[0030]
After vulcanization, the flexible jacket 42 is contracted, the inner die 41 is pulled out from the outer die 46, and then the vulcanized belt sleeve 51b attached to the outer die 46 is pulled out.
[0031]
A vulcanized belt sleeve 51b with short fibers attached to the surface of the rib is attached to one axis or cut to a predetermined width in the circumferential direction while rotating while hanging around two axes of a main axis and a driven axis, and then taken out from the axis and inverted. By doing so, a plurality of V-ribbed belts 1 having a constant circumference and V-shaped ribs are accurately formed and formed.
[0032]
FIG. 6 is a sectional view of the obtained V-ribbed belt. The V-ribbed belt 100 has a cord 102 made of a cord of high strength and low elongation embedded in an adhesive rubber layer 103, and has a compression rubber layer 104 as an elastic layer below the core. The compressed rubber layer 104 is provided with a plurality of ribs 106 having a substantially triangular cross section extending in the longitudinal direction of the belt, and short fibers 109 are arranged in a wavy manner on the inner layer 110 of the ribs to improve the lateral pressure resistance of the belt. The short fibers 108 are dispersed in the adhesive layer 107 provided on the surface layer 111 of the rib portion, and are randomly inclined or laid down on the surface of the rib portion.
Of course, the present invention includes a case where the short fiber 109 does not exist in the inner layer 110 of the rib portion.
[0033]
The rubber used for the adhesive rubber layer 103 is similar to the rubber compound of the compressed rubber layer 104 except for short fibers. Of course, short fibers may be included.
[0034]
As the core wire 102, polyester fiber, aramid fiber, and glass fiber are used, and among them, a total denier of 4,000 to 8, which is obtained by twisting a polyester fiber filament group having ethylene-2,6-naphthalate as a main constituent unit, is used. 000 bonded cords are preferred because the belt slip rate can be kept low and the belt life is extended. The core wire 102 is subjected to an adhesive treatment for the purpose of improving the adhesiveness with rubber. As such an adhesive treatment, the fiber is generally immersed in a resorcinol-formalin-latex (RFL) solution and then dried by heating to form an adhesive layer uniformly on the surface. However, without being limited to this, there is a method of performing a pretreatment with an epoxy or isocyanate compound and then treating with an RFL solution.
[0035]
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 runs over the adjacent cord and cannot be wound, while if it exceeds 1.3 mm, the modulus of the belt gradually decreases.
[0036]
The back reinforcing member 105 is selected from a fiber material or a rubber material of a woven fabric, a knitted fabric, or a nonwoven fabric, and a more preferable one is a nonwoven fabric. Examples of the 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. No. The canvas is immersed in an RFL solution according to a known technique, and then subjected to friction for rubbing the unvulcanized rubber with the back reinforcing material 105, and then immersed in a soaking solution in which the rubber is dissolved in a solvent after immersion in the RFL solution.
[0037]
In such a V-ribbed belt, the short fibers 108 adhering to the surface of the rib reduce noise during belt running, and also prevent the generation of cracks from the surface of the rib.
[0038]
【The invention's effect】
As described above, in the invention according to the claims of the present application, the short fiber is attached via an adhesive applied to the inner peripheral surface of the outer mold in which a rib mold is stamped on the inner peripheral surface, and the uncured A rubber sheet is interposed between an outer mold to which an adhesive is attached and an inner mold having a flexible jacket attached to the outer peripheral surface, and the flexible jacket is inflated so that the rubber sheet is engraved on the outer mold. A non-vulcanized pre-molded body is produced in close contact with the mold, and at least a core wire is wound around the flexible jacket surface of the inner mold separated from the outer mold, and the inner mold is set in the outer mold again, A transmission that expands the flexible jacket and vulcanizes integrally with the preform with the core wire attached to the outer mold, cures the adhesive, and creates a vulcanized belt sleeve with ribs to which short fibers are attached. It is in the belt manufacturing method, and the rib part of the vulcanized belt sleeve is accurately manufactured by molding. In addition, the adhesive containing short fibers adhering to the inner peripheral surface of the outer mold is cured during vulcanization to be transferred to the rib surface of the vulcanized belt sleeve, and the short fibers are adhered to the rib surface. There is an effect that can be done.
[Brief description of the drawings]
FIG. 1 is a view showing a state in which an uncured adhesive mixed with short fibers is sprayed on the inner peripheral surface of an outer mold 46 to form a short fiber mixed coating film.
FIG. 2 is a longitudinal sectional view showing a state in which a preform is being formed.
FIG. 3 is a cross-sectional view of a state after a preformed body is manufactured.
FIG. 4 is a sectional view of a state before an unvulcanized belt sleeve is manufactured.
FIG. 5 is a cross-sectional view of a state where the belt sleeve is vulcanized.
FIG. 6 is a sectional view of a V-ribbed belt obtained by the manufacturing method of the present invention.
[Explanation of symbols]
7 Short fiber 8 Short fiber mixed coating film 9 Adhesive 10 Spray 20 Rubber sheet 21 Preform 41 Inner mold 42 Flexible jacket 45 Rib mold 46 Outer mold 48 Core wire 51b Vulcanized belt sleeve 62 Rib surface 63 Adhesive Coating device 64 Pile supply device 65 Short fiber 66 Adhesive layer

Claims (3)

In a method for manufacturing a power transmission belt having a rubber layer in which a cord is embedded along the belt longitudinal direction and a rib portion extending in the longitudinal direction of the belt adjacent to the rubber layer,
The short fibers are attached via an adhesive applied to the inner peripheral surface of the outer mold in which a rib mold is engraved on the inner peripheral surface,
A rubber sheet is interposed between the outer mold having the short fibers attached to the inner peripheral surface and the inner mold having a flexible jacket attached to the outer peripheral surface,
The flexible jacket is inflated and the rubber sheet is brought into close contact with a stamped rib mold of an outer mold to produce an unvulcanized preform,
At least a core wire is wound around the flexible jacket surface of the inner mold detached from the outer mold, and the inner mold is placed in the outer mold again, and the flexible jacket is expanded to attach the core wire to the outer mold. Vulcanizing integrally with the molded body to produce a vulcanized belt sleeve with short fibers attached to the rib surface,
A method for manufacturing a power transmission belt, comprising: The method according to claim 1, wherein the rubber sheet contains short fibers and is oriented. The method for producing a power transmission belt according to claim 1, wherein the rubber sheet does not contain short fibers.

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