JP2004251402A - Driving belt and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a driving belt having noises reduced during travelling by raising short fibers of a non-woven cloth deposited on the driving surface of an accurately shaped rib portion, and to provide its manufacturing method. <P>SOLUTION: The driving belt comprises an adhesive rubber layer 103 in which core wires 102 are embedded along the longitudinal direction of the belt and the rib portion 106 located adjacent to the rubber layer 103 and extending to the longitudinal direction of the belt. The belt has noises reduced during travelling by polishing the rib portion at its surface 111 and raising the short fibers 109 of the non-woven cloth 107. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power transmission belt and a method of manufacturing the same, and more particularly, to a power transmission belt in which noise generated during running of the belt is reduced by raising short fibers of a nonwoven fabric attached to a power transmission surface of a precisely formed rib.
[0002]
[Prior art]
Conventionally, as a method of orienting the short fibers in a certain direction in the unvulcanized rubber, the unvulcanized rubber containing the short fibers is put into a pair of calender rolls having different rotation speeds in a rolled sheet manufacturing step, and the rolled sheet is rolled. The short fibers in the rubber sheet were oriented in the rolling direction of the sheet and cut according to the belt width to be formed. After that, in the laminating step, several rolled sheets cut in the laminating step are laminated and laminated to a predetermined thickness, and then in the winding step, a belt formed body obtained by winding a laminate in which short fibers are oriented in the width direction around a forming drum is obtained. The belt was vulcanized, and a plurality of ribs were ground on the surface of the belt sleeve by a glider wheel, and short fibers were projected on the surface of the ribs to produce a belt with reduced running noise. However, if the thickness of the rolled sheet is not reduced, the short fibers cannot be sufficiently oriented in the sheet rolling direction. Was.
[0003]
As a method of improving this, it has been proposed to use a short fiber-containing rubber composition formed into a sheet with an expansion die for a power transmission belt. For example, in Patent Document 1, a cylindrical rib rubber tube is extruded by an extruder provided with an expansion die having a V-rib portion forming 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. And vulcanizing, and grinding the surface of the V-rib portion of the belt formed body to expose the short fibers to the surface of the rib portion to produce a V-ribbed belt with reduced running noise. ing.
[0004]
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 No. H11-157572 discloses a method in which raised hair is provided on at least one of the power transmission side and the transmission surface in contact with the power transmission side by electrostatic flocking. A power transmission member with reduced noise is described.
[0005]
Further, Patent Document 3 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.
[0006]
[Patent Document 1]
JP-A-8-74936 [Patent Document 2]
Japanese Patent Application Laid-Open No. 9-14361 [Patent Document 3]
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.
[0008]
The present invention pays attention to such a problem and, as a result of intensive research, has provided a transmission belt in which noise generated during belt running is reduced by raising short fibers of a nonwoven fabric adhered to a transmission surface of a precisely formed rib portion, and a method of manufacturing the same. The purpose is to do.
[0009]
[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 having a core buried along the belt longitudinal direction and a rib portion extending in the belt longitudinal direction adjacent to the rubber layer. In the power transmission belt, the short fibers of the nonwoven fabric provided on the rib surface are raised, and the short fibers raised from the nonwoven fabric reduce noise when the belt runs.
[0010]
The invention according to claim 2 of the present application resides in a power transmission belt in which short fibers are oriented in the belt width direction in the rubber of the rib portion, and the oriented short fibers improve the lateral pressure resistance of the belt.
[0011]
The invention according to claim 3 of the present application is a power transmission belt in which short fibers are not present in the rubber of the rib portion, and can provide an inexpensive belt.
[0012]
The invention according to claim 4 of the present application is directed to a method for manufacturing a power transmission belt having a rubber layer in which a cord is buried along the belt longitudinal direction and a rib portion extending in the longitudinal direction of the belt adjacent to the rubber layer.
A laminate of a rubber sheet and a nonwoven fabric is interposed between an inner mold having a flexible jacket attached to the outer peripheral surface and an outer mold having a rib mold stamped on the inner peripheral surface,
The flexible jacket is expanded to produce an unvulcanized preform so that the nonwoven fabric of the laminate adheres to the engraved rib mold of the outer mold,
At least a core wire is wound around the flexible jacket surface of the inner mold detached from the outer mold,
Again, placing the inner mold in the outer mold, inflating the flexible jacket and vulcanizing integrally with the preformed body with the core wire attached to the outer mold,
Demold to produce a vulcanized belt sleeve with ribs,
A method for manufacturing a power transmission belt, wherein the surface of a rib portion of the vulcanized belt sleeve is polished to raise short fibers of a nonwoven fabric.
[0013]
According to this manufacturing method, it is possible to accurately mold the rib portion of the vulcanized belt sleeve using a laminate of the rubber sheet and the nonwoven fabric, and also to partially raise the short fibers of the nonwoven fabric by polishing the surface of the rib portion. Thus, there is provided a method of manufacturing a power transmission belt in which noise during running of the belt is reduced.
[0014]
The invention according to claim 5 of the present application resides in a method for manufacturing a power transmission belt in which a laminated sheet of a rubber sheet and a nonwoven fabric contains oriented short fibers.
[0015]
The invention according to claim 6 of the present application is a method for manufacturing a power transmission belt in which a rubber sheet and a nonwoven fabric are laminated and the rubber sheet does not contain short fibers.
[0016]
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 rubber sheet in which short fibers are oriented in the width direction is produced, and as a production method, there are an extrusion method and a rolling method using a calender. Of course, a rubber sheet containing no short fibers can also be used. When preparing a rubber sheet in which fibers are oriented in the width direction 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 prepared. Once released, this is cooled to 20-50 ° C to prevent rubber scorch.
[0017]
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 of the elementary fibers, prevents the short fibers from becoming cottony, and reduces the familiarity between the short fibers and the rubber. It improves and the dispersion of short fibers improves.
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.
[0019]
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.
[0020]
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.
[0021]
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. Short fibers of about 1 to 10 mm are used. For example, aramid fiber is 3 to 5 mm. In the case of polyamide fiber, polyester fiber or cotton, about 5 to 10 mm is used. The addition amount is 10 to 40 parts by mass based on 100 parts by mass of the rubber.
[0022]
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.
[0023]
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.
[0024]
Next, as shown in FIG. 1, the laminate 14 obtained by winding the short fiber oriented rubber sheet 20 and the nonwoven fabric 16 is used to form a constant gap inside the inner die 41 of the belt vulcanizer 40 and the outer die 46. Place on the base. 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.
[0025]
The nonwoven fabric 16 used here is made of a fiber such as polyethylene, polypropylene, polyamide, polyester, acrylic, or glass fiber having a length of 5 to 60 mm. For example, the fibers in the web are entangled by mechanical action and entangled. It is formed by a needle punch or the like that produces strength, and is not binder-treated. The basis weight of the nonwoven fabric is preferably from ²⁰ to 100 g / m2.
[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 short fiber oriented rubber sheet 20 is pressed by the rib mold 45 of the outer mold 46 by the expansion pressing force of the flexible jacket 42, and the unvulcanized uncured rubber sheet having a plurality of V-shaped protrusions on the surface as shown in FIG. Is formed.
[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. 1 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. 3, the inner mold 41 is placed in the outer mold 46, and then the flexible jacket 42 is expanded as shown in FIG. 4, 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.
[0030]
After the vulcanization, as shown in FIG. 5, the flexible jacket 42 is contracted, the inner die 41 is pulled out from the outer die 46, and then the vulcanized belt sleeve 51 attached to the outer die 46 is pulled out.
[0031]
In order to grind the surface of the rib portion of the vulcanized belt sleeve 51 for surface processing, as shown in FIG. 6, the belt sleeve 51 is stretched around two axes of a main shaft 55 and a driven shaft 56 while running. The grinding wheel 57 on which the diamond is electrodeposited is rotated while being abutted to grind the rib surface 62 to about 0.05 to 0.1 mm, whereby the short fibers of the nonwoven fabric attached to the rib surface 62 are raised.
[0032]
Then, the vulcanized belt sleeve 51 is inserted into another one-axis or two-axis drum, cut into a predetermined width in the circumferential direction while rotating, and is taken out from the drum and inverted, so that the circumference is constant and V A plurality of V-ribbed belts 1 in which the shape ribs are accurately formed are obtained.
[0033]
FIG. 7 is a sectional perspective 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. Short fibers 108 raised randomly from the nonwoven fabric 107 attached to the surface layer 111 of the rib portion are dispersed, and the short fibers 108 cover the rib portion surface.
[0034]
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.
[0035]
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.
[0036]
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.
[0037]
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 a resorcinol-formalin-latex solution (RFL solution) according to a known technique and then frictionally rubbed with an unvulcanized rubber against the back reinforcing material 105, or soaked in a solvent after immersion in the RFL solution. Immerse in liquid.
[0038]
In the V-ribbed belt obtained in this manner, the short fibers 108 raised from the nonwoven fabric 107 on the rib surface 111 reduce noise during belt running and also prevent the generation of cracks from the rib surface.
[0039]
【The invention's effect】
As described above, in the power transmission belt and the method for manufacturing the same according to the present application, it is possible to accurately mold the rib portion of the vulcanized belt sleeve by using a laminate of the rubber sheet and the nonwoven fabric, and to form the surface of the rib portion. The polishing can partially raise the attached short fibers of the nonwoven fabric, thereby providing a power transmission belt with reduced noise during belt running.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a state in which a preform is being formed.
FIG. 2 is a cross-sectional view of a state after a preformed body is manufactured.
FIG. 3 is a sectional view showing a state before an unvulcanized belt sleeve is manufactured.
FIG. 4 is a cross-sectional view of a state where the belt sleeve is vulcanized.
FIG. 5 is a sectional view showing a state after vulcanizing the belt sleeve.
FIG. 6 is a diagram showing a state in which the rib surface of the belt sleeve is being polished.
FIG. 7 is a sectional perspective view of a V-ribbed belt obtained by the manufacturing method of the present invention.
[Explanation of symbols]
14 laminated material 16 nonwoven fabric 20 rubber sheet 21 preform 41 inner mold 42 flexible jacket 46 outer mold 48 core wire 100 V-ribbed belt 102 core wire 103 adhesive rubber layer 104 compressed rubber layer 106 rib portion 107 nonwoven fabric 108 brushed short fibers 111 rib surface

Claims (6)

In a power transmission belt having a rubber layer in which a cord is buried along the belt length direction and a rib portion extending in the belt length direction adjacent to the rubber layer, the nonwoven fabric short fibers provided on the rib portion surface are raised. A transmission belt characterized by the following. The power transmission belt according to claim 1, wherein the short fibers are oriented in the belt width direction in the rubber of the rib portion. The power transmission belt according to claim 1, wherein no short fibers are present in the rubber of the rib portion. 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,
A laminate of a rubber sheet and a nonwoven fabric is interposed between an inner mold having a flexible jacket attached to the outer peripheral surface and an outer mold having a rib mold stamped on the inner peripheral surface,
The flexible jacket is expanded to produce an unvulcanized preform so that the nonwoven fabric of the laminate adheres to the engraved rib mold of the outer mold,
At least a core wire is wound around the flexible jacket surface of the inner mold detached from the outer mold,
Again, placing the inner mold in the outer mold, inflating the flexible jacket and vulcanizing integrally with the preformed body with the core wire attached to the outer mold,
Demold to produce a vulcanized belt sleeve with ribs,
A method of manufacturing a power transmission belt, characterized in that the surface of a rib portion of the vulcanized belt sleeve is polished to raise short fibers of a nonwoven fabric. The method for producing a power transmission belt according to claim 4, wherein in a laminate of the rubber sheet and the nonwoven fabric, the rubber sheet contains oriented short fibers. The method for producing a power transmission belt according to claim 4, wherein in the laminate of the rubber sheet and the nonwoven fabric, the rubber sheet does not contain short fibers.

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