JP4071131B2 - Transmission belt manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
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.
[0002]
[Prior art]
In a conventional transmission belt manufacturing method, a belt molded 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 belt in which a plurality of ribs are ground on the surface and short fibers protrude from the surface of the ribs to reduce noise during travel has been manufactured.
[0003]
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 1 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.
[0004]
Further, Patent Document 2 discloses a transmission belt in which a flocked fabric is attached to the belt surface and a driving surface having an increased friction coefficient is provided.
[0005]
[Patent Document 1]
Japanese Patent Laid-Open No. 9-14361 [Patent Document 2]
Japanese Patent Laid-Open No. 2001-82549
[Problems to be solved by the invention]
However, in the method of manufacturing a transmission belt having a rib portion, if the hair is raised directly on the surface of the rib portion by electrostatic flocking, even if flocking can be made near the entrance of the V-shaped rib groove, the flocking is deep in the rib groove. Development of a new manufacturing method has been desired. 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.
[0007]
This invention pays attention to such a problem, and as a result of earnest research, an object of the present invention is to provide a method of manufacturing a transmission belt in which short fibers are uniformly attached to the transmission surface of the rib portion to reduce noise during belt running.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 of the present application is a transmission belt having a rubber layer in which a core wire is embedded along the longitudinal direction of the belt and a rib portion adjacent to the rubber layer and extending in the longitudinal direction of the belt. 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 in which short fibers are attached to the inner peripheral surface and the inner mold in which a flexible jacket is attached to the outer peripheral surface,
The flexible jacket is inflated, and the rubber sheet is closely attached to the rib mold stamped on the outer mold to produce an unvulcanized preform.
At least a core wire is wound around the inner flexible jacket surface separated from the outer die, and the inner die is again installed in the outer die, and the flexible jacket is expanded to attach the core wire to the outer die. There is a transmission belt manufacturing method in which a vulcanized belt sleeve is produced by vulcanizing integrally with a molded body and attaching short fibers to the surface of the rib portion.
[0009]
In this manufacturing method, the rib portion of the vulcanized belt sleeve can be accurately produced by molding, and further, the short fiber mixed adhesive adhered to the inner peripheral surface of the outer mold is cured at the time of vulcanization so that the vulcanized belt sleeve It is possible to transfer to the rib surface and to attach the short fibers to the rib surface.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below 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. As a manufacturing method thereof, there are an extrusion method and a rolling method using a calendar. Of course, a rubber sheet which does not contain short fibers can also be used. When a rubber sheet with oriented fibers is prepared by an extrusion method, 10 to 40 parts by mass of short fibers are introduced into 100 parts by mass of the polymer in advance using an open roll, and then the kneaded master batch is discharged once. This is cooled to 20 to 50 ° C. to prevent rubber scorching.
[0011]
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, a single rubber sheet in which short fibers are oriented in the width direction can be finished using an extrusion apparatus in which an expansion die is attached to an extruder. Although not shown here, after the master batch is kneaded with the extrusion screw of the cylinder in the extruder, the rubber mixed with the short fiber is located between the inner dies arranged on the same central axis at the position facing the cylinder. Cylindrical molded body in which short fibers are oriented in the circumferential direction while flowing through the rubber passage of the expansion die smoothly without being disturbed by the flow in the rubber passage and without changing the flow direction. Extruded.
[0013]
After that, the cylindrical molded body without weld line continuously extruded is one having a thickness of 1 to 10 mm in which short fibers are uniformly oriented in the circumferential direction from the inner layer to the outer layer. Then, one short fiber oriented rubber sheet is formed, and then the rubber sheet is cut at a predetermined interval.
[0014]
As 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 carboxylic acid metal salt Or 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. Examples of diene monomers 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, but short fibers of about 1 to 10 mm are used. For example, the aramid fiber is 3 About 5 mm, polyamide fiber, polyester fiber, and cotton are about 5-10 mm. The addition amount is 10 to 40 parts by mass with respect to 100 parts by mass of rubber.
[0016]
Furthermore, a softener, a reinforcing agent composed of carbon black, a filler, an anti-aging agent, a vulcanization accelerator, a vulcanizing agent, and the like are added to the rubber.
[0017]
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.
[0018]
Next, as shown in FIG. 1, after applying a release agent such as silicon oil on the surface of the protruding rib mold 45, which is stamped on the inner peripheral surface of the cylindrical outer mold 46 at a constant interval, the short fibers 7 are applied. The mixed uncured adhesive 9 is sprayed by a spray 10 to form a short fiber mixed coating film 8 having a thickness of about 0.5 to 3 mm. The temperature of the inner peripheral surface of the outer mold 46 at this time is room temperature, preferably 20 to 100 ° C., and is a temperature at which the adhesive of the short fiber-containing coating film 8 is not cured. The temperature of the outer mold 46 is adjusted through a heat medium such as water vapor or a coolant such as water in a space (not shown) provided in the main body.
[0019]
As the adhesive 9 mixed with the short fiber 7 used here, an RFL (resoricin-formaldedo-latex) adhesive, vinyl acetate emulsion, styrene emulsion, unvulcanized rubber is dissolved in a solvent such as toluene or xylene. Rubber glue, organic solvent adhesives, etc. As a preferable adhesive, RFL liquid or rubber paste is preferable, and a thermosetting reaction is performed simultaneously with vulcanization molding. 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. It is an α-olefin-diene copolymer. An isocyanate compound can also be added to the RFL solution.
[0020]
In the short fiber spraying method, short fibers made of polyester, nylon, aramid, vinylon, carbon fiber, polytetrafluoroethylene, cotton, etc. are used. The short fiber mixed coating film 8 is formed on the surface 45.
[0021]
The length of the short fiber is preferably 0.1 to 5.0 mm, and the aspect ratio (length Lmm / thickness diameter Dmm is 30 to 300. Further, the fiber density contributes to the friction coefficient and sound during running. It is a thing near the power transmission belt used today, and is 10,000 to 500,000 pieces / cm ² .
[0022]
As another method, after spraying an adhesive that does not mix short fibers 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-type coating device. It can also be attached.
[0023]
As another method, after spraying only a solvent such as toluene, xylene or the like as an adhesive 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 with a spray-type coating device. Can also be applied by spraying.
[0024]
As another method, after spraying an adhesive on the surface of the protruding rib mold 45 provided on the inner peripheral surface of the cylindrical outer mold 46, the outer mold 46 is charged and the short fibers are blown by electric lines of force. You can also plant hair.
[0025]
Subsequently, as shown in FIG. 2, the inner die 41 in which the adhesive rubber sheet 16 and the rubber sheet 20 that forms the compression rubber layer are sequentially wound on the surface of the flexible jacket 42 provided on the outer peripheral surface of the inner die 41. Then, it is placed on the base so as to form 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.
[0026]
The medium feeding machine is operated to feed the flexible jacket 42 through the medium feeding / discharge path B and the medium circulation port A such as high-pressure air. 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 short fiber oriented rubber sheet 20 mounted on the outer peripheral surface thereof is uniformly expanded in the radial direction and heated to 100 to 160 ° C. with a heater or high-temperature steam and the rib mold 45 of the outer mold 46 and 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 an unvulcanized pre-molding having a plurality of V-shaped protrusions on the surface as shown in FIG. The body 21 is formed. The preform 21 is attached to the short fiber-containing coating film 8, but at this stage, the short fiber-containing coating film 8 is not cured and is not integrally joined to the preform 21.
[0028]
After that, the valve is switched to the vacuum pump, the air filled in the flexible jacket 42 is exhausted, and then the flexible jacket 42 is contracted and returned to the original position shown in FIG. .
[0029]
Then, the inner mold 41 is extracted from the outer mold 46, and a reinforcing cloth 47 and a cord 48 made of a cord are sequentially wound around the outer peripheral surface of the flexible jacket 42 of the inner mold 41. Thereafter, after the inner die 41 is installed in the outer die 46 as shown in FIG. 4, the flexible jacket 42 is expanded as shown in FIG. 5, and the reinforcing cloth 47 and the core wire 48 are made uniform in the radial direction. The belt sleeve 51 is produced by inflating and intimately vulcanizing the preformed body 21 attached to the rib mold 45 of the outer mold 46 heated to 100 to 180 ° C. with a heater or high temperature steam. By molding the unvulcanized preform 21 as in the above manufacturing method, the extension amount of the core wire 48 due to the expansion of the flexible jacket 42 can be suppressed at the time of molding, and the core wire 48 can be arranged flatly. A V-ribbed belt excellent in stability can be produced.
At the same time, the short fiber-containing coating film 8 is cured 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 and the inner mold 41 is extracted from the outer mold 46, and then the vulcanized belt sleeve 51b attached to the outer mold 46 is extracted.
[0031]
A vulcanized belt sleeve 51b with short fibers attached to the rib surface is attached to one shaft, or is stretched around two shafts of the main shaft and driven shaft, and is cut to a predetermined width in the circumferential direction while rotating and taken out from the shaft and reversed. By doing so, a plurality of V-ribbed belts 1 having a constant circumferential length and V-shaped ribs accurately formed are obtained.
[0032]
FIG. 6 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. This compressed rubber layer 104 is provided with a plurality of rib portions 106 having a substantially triangular cross section extending in the longitudinal direction of the belt, and short fibers 109 are arranged in a wave shape on the inner layer 110 of the rib portion 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 with respect to the rib portion surface.
Of course, the present invention includes a case where the short fiber 109 is not present 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 excluding short fibers. Of course, short fibers may be included.
[0034]
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.
[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 cannot ride on 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 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 canvas is immersed in an RFL solution according to a known technique, then subjected to friction in which unvulcanized rubber is rubbed into the back reinforcing material 105, and immersed in an RFL solution and then immersed in a soaking solution in which the rubber is dissolved in a solvent.
[0037]
In such a V-ribbed belt, the short fibers 108 attached to the rib portion surface reduce noise during belt running, and further prevent cracks from occurring on the rib portion surface.
[0038]
【The invention's effect】
As described above, in the invention according to the claims of the present application, the short fibers are attached via the adhesive applied to the inner peripheral surface of the outer mold in which the rib mold is engraved on the inner peripheral surface, and uncured on the inner peripheral surface. A rib in which a rubber sheet is interposed between an outer mold with an adhesive attached and an inner mold with a flexible jacket mounted on the outer peripheral surface, and the flexible jacket is expanded to engrave the rubber sheet on the outer mold An unvulcanized preform is prepared in close contact with the mold, and at least a core wire is wound around the inner flexible jacket surface separated from the outer mold, and the inner mold is placed in the outer mold again. Power transmission to create a vulcanized belt sleeve with ribs that are inflated with a flexible jacket and vulcanized integrally with a preform with the core attached to the outer mold and cured with adhesive to which short fibers are attached In the manufacturing method of the belt, the rib part of the vulcanized belt sleeve is accurately produced by molding In addition, the short fiber mixed adhesive adhered to the inner peripheral surface of the outer mold can be cured during vulcanization and transferred to the rib surface of the vulcanized belt sleeve, and the short fiber can be 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 molded.
FIG. 3 is a cross-sectional view of a state after a preform is manufactured.
FIG. 4 is a cross-sectional view of a state before producing an unvulcanized belt sleeve.
FIG. 5 is a cross-sectional view of a state in which a belt sleeve is vulcanized.
FIG. 6 is a cross-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 Preliminary molded body 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 of manufacturing a 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 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 in which short fibers are attached to the inner peripheral surface and the inner mold in which a flexible jacket is attached to the outer peripheral surface,
The flexible jacket is inflated, and the rubber sheet is closely attached to the rib mold stamped on the outer mold to produce an unvulcanized preform.
At least a core wire is wound around the inner flexible jacket surface separated from the outer die, and the inner die is again installed in the outer die, and the flexible jacket is expanded to attach the core wire to the outer die. Vulcanized integrally with the molded body to produce a vulcanized belt sleeve with short fibers attached to the rib surface.
A method of manufacturing a power transmission belt characterized by the above. The method for manufacturing a transmission belt according to claim 1, wherein the rubber sheet includes short fibers and is oriented. The method for producing a transmission belt according to claim 1, wherein the rubber sheet does not contain short fibers.

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