JP2004284104A - Transmission belt manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmission belt manufacturing method for simplifying the joining work in the cog ridge parts of a sheet for a compressed rubber while reducing the defective percent of the joining work to manufacture a low cost cogged belt. <P>SOLUTION: Reinforcing cloth 6 is held between a mold 1 alternately having ridge-like parts 4 and grove-like parts 5 and the pinion roll 7 meshed with the ridge-like parts 4 and grove-like parts 5 to be shaped while synchronously rotating the mold 1 and the pinion roll 7 and the sheet for the compressed rubber is wound around the mold 1 to join the cut surfaces of the sheet in a butted state. After a stickiness preventing material is wound around the surface of the sheet for the compressed rubber, the sheet for the compressed rubber is heated under pressure and closely brought into contact with the ridge-like parts 4 and grove-like parts 5 of the mold and shaped. At least a core wire and a stretched rubber sheet are successively wound around the surface of the unvulcanized sheet for the compressed rubber from which the stickiness preventing material is removed to form a belt molded object. This belt molded object is vulcanized and the obtained vulcanized sleeve is cut into a V-shape to manufacture the transmission belt. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing a transmission belt, which is a cogged belt used as a transmission belt for snowmobiles, scooters, and general industry, and more particularly, to simplify a joining operation at a cog peak portion of a compressed rubber sheet, and to reduce a joining operation. The present invention relates to a method for manufacturing a power transmission belt capable of manufacturing a low-cost cogged belt with a reduced occurrence of a defective rate.
[0002]
[Prior art]
BACKGROUND ART Conventionally, in a scooter or a drive system of a general industrial machine field, a belt-type transmission that suspends a transmission belt between a drive pulley and a driven pulley, and changes the effective diameter of the pulley to change the speed has been used. The transmission belt used here has a cog portion in which a cog peak portion and a cog valley portion are alternately arranged on at least one of the compression rubber layer and the extension rubber layer, and the core wire is placed in the adhesive rubber layer. A low-edge cog belt such as a low-edge single cog belt or a low-edge double cog belt has been known.
[0003]
As the method (1) of the method for producing a low-edge cogged belt, an outer reinforcing cloth, a rubber sheet of an extension rubber layer, a cord, a rubber sheet of a compression rubber layer, and an inner reinforcing cloth are sequentially wound on a molding die. A method of molding a rubber sheet of a compressed rubber layer by inserting a cylindrical matrix having alternating protrusions and grooves, and then vulcanizing, by shrinking the inner reinforcing cloth by pressure during vulcanization. There is. (For example, disclosed in Patent Document 1.)
[0004]
Also, as (2), an unvulcanized rubber sheet is placed on a flat grooved mold longer than the belt circumference prepared in advance and heated and pressed by a press to produce a cog pad molded into a cog shape. I do. This cog pad is fitted into the protrusion and groove of the cylindrical mother die mounted on the forming drum, and the cut surfaces of the cog pad are butt-joined, then the core wire is wound, and another rubber layer and a reinforcing cloth are added to the cog pad. The molding was completed by winding from the top and moving to the vulcanization process. (For example, disclosed in Patent Document 2.)
[0005]
Further, as (3), a canvas placed on a flat grooved mold is molded with a pinion roll, and then a rubber sheet is placed and pressed by a press to produce a cog pad molded into a cog shape. I do. This cog pad is fitted into the protrusion and groove of the cylindrical mother die mounted on the forming drum, and the cut surfaces of the cog pad are butt-joined, then the core wire is wound, and another rubber layer and a reinforcing cloth are added to the cog pad. The molding was completed by winding from the top and moving to the vulcanization process. (For example, disclosed in Patent Document 3)
[0006]
[Patent Document 1]
U.S. Pat. No. 3,646,875 [Patent Document 2]
Japanese Patent Application Laid-Open No. 2002-1691 [Patent Document 3]
JP-A-2002-188691
[Problems to be solved by the invention]
However, transmission belts for transmissions such as conventional scooters have been mainly composed of chloroprene rubber, but recently transmission belts having more heat resistance, lateral pressure resistance, and wear resistance have been required. . Therefore, in the method (1), when a belt having a small shrinkage is used as the core of the belt, the core does not shrink when the rubber sheet of the compression rubber layer and the inner canvas are press-fitted during vulcanization. There was a meandering defect.
[0008]
In the method of (2) for preparing a cog pad in advance, an unvulcanized rubber sheet cut into a predetermined length in advance is placed on a flat press and heated and pressed. It is necessary to cut to the required length, and the flat press requires die replacement, which results in a time loss in setup change and the like.
[0009]
In addition, the cutting of the molded cog pad is performed manually by a skilled worker, and the worker counts the number of cogs in advance according to the belt circumference and marks the cog valley to be cut with chalk. One cog peak (the top of the cog) was cut by a cutter, and the other cog peak was similarly cut.
[0010]
However, when the molded body obtained by this method is vulcanized, the outer canvas of the reinforcing cloth is stretched at the cog portion of the transmission belt due to the rubber flow due to the insufficient volume of the rubber located at the joint portion, and the inner fabric is stretched. The edges of the canvas were attracted, resulting in the inner canvas wrinkling in the cog valley. When this belt was run, the cog valleys became repetitive bending points, and cracks sometimes occurred early from the wrinkles. These grew and became cracks in the full-fledged cog valley, damaging the belt. Further, when the cog shape of the joint portion is not uniform and the volume is particularly large, stress is concentrated during running bending, and the joint portion may be damaged at an early stage.
[0011]
Further, in the methods (2) and (3), chloroprene and the like are easy to mold because of their high adhesiveness to the mold, but alkylated chlorosulfanated polyethylene, hydrogenated nitrile rubber, and hydrogen Rubber with excellent heat resistance, such as a mixed polymer of a nitrile rubber and an unsaturated metal salt of a carboxylic acid, has poor adhesiveness. Therefore, when molded using this rubber sheet and a reinforcing cloth treated with this rubber, the rubber is reinforced. The cloth and the rubber sheet peeled off and could not be molded. In particular, when a canvas is molded with a pinion roll, the reinforcing cloth sometimes floats in the air without following the mold. When the transmission belt thus molded was subjected to high load transmission, cracks were easily generated from the cog valleys of the compressed rubber.
[0012]
The present invention solves the above-mentioned problems, simplifies the joining operation at the cog ridges of the compressed rubber sheet, and reduces the occurrence of a defective rate of the joining operation to produce a low-cost cogged belt for power transmission. It is intended to provide a method for manufacturing a belt.
[0013]
[Means for Solving the Problems]
According to the first aspect of the present invention, at least the compression rubber layer of the compression rubber layer and the extension rubber layer has a cog portion in which cog peaks and cog valleys are alternately arranged, and the core wire is embedded in the adhesive rubber layer. In the manufacturing method of the transmission belt formed as described above,
The reinforcing cloth is sandwiched between a molding die having a projection and a groove portion alternately and a pinion roll meshing with the projection and the groove portion, and the molding die and the pinion roll are molded while rotating synchronously,
A sheet for compressed rubber that forms a compressed rubber layer is wound around a molding die, the cut surfaces are butt-joined,
After wrapping an anti-adhesive material on the surface of the compressed rubber sheet, the compressed rubber sheet is heated and pressurized to form a projection and a groove of a molding die,
An unvulcanized compressed rubber sheet from which the anti-adhesive material has been removed is wrapped with an expanded rubber sheet that forms at least a core wire and an expanded rubber layer on the surface of the unvulcanized compressed rubber sheet to form a belt molded body, and then vulcanized. A method for manufacturing a power transmission belt, comprising cutting a sulfurized sleeve into a V shape to produce a power transmission belt.
[0014]
According to the present invention, the reinforcing cloth is sandwiched between a molding die having projections and grooves alternately and a pinion roll meshing with the projections and the grooves, and the molding die and the pinion roll are rotated synchronously. The compressed rubber sheet for forming the compressed rubber layer is wound around a molding die, the cut surfaces are butt-joined, and an anti-adhesive material is wound around the surface of the compressed rubber sheet. Heating and pressurizing the sheet and molding it in close contact with the protruding part and groove part of the molding die eliminates the need for skilled workers to joint the rubber and reinforcing cloth at the cog peaks, and the position of the joint The quality of the product can be stabilized by eliminating cracks and wrinkles of the reinforcing cloth, which are defects due to insufficient volume of rubber, which reduces the work-in-progress because there is no need to prepare cog pads in advance. Is possible , It is possible to inlining of production.
[0015]
According to the second aspect of the present invention, after the rubber-based adhesive is applied to the surface of the molding die, the reinforcing cloth is interposed between the pinion roll and the projection and the groove of the molding die while being rotated. In the method for manufacturing a power transmission belt in which the reinforcing cloth is sandwiched, the reinforcing cloth can be surely molded by using a rubber-based adhesive.
[0016]
According to a third aspect of the present invention, there is provided a method for manufacturing a power transmission belt in which the ends of a compressed rubber sheet are butted at a bias cut surface, and the joined portion is joined by heating and pressing. can do.
[0017]
The invention according to claim 4 of the present application resides in a method for manufacturing a power transmission belt which is at least one resin film selected from polymethylpentene and polyethylene terephthalate, and uses a film having heat resistance and excellent release properties. be able to.
[0018]
In the invention according to claim 5 of the present application, an anti-adhesive material is wrapped around the surface of the compressed rubber sheet, the molding die covered with the jacket is placed in a vulcanized can, and the compressed rubber sheet is heated and pressed to form a molding die. This is a method of manufacturing a power transmission belt in which the protruding portions and the groove portions are pressurized and molded, and an unvulcanized compressed rubber sheet can be molded by applying heat and pressure in a known vulcanizing can.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 shows a step of molding a reinforcing cloth into a molding die in the production method of the present invention, and FIG. 2 shows a step of winding a compressed rubber sheet around the molding die and joining the cut surfaces by abutting the cut surfaces. 3 shows a process in which an anti-adhesive material is wound around the surface of the compressed rubber sheet, and FIG. 4 shows a process in which the compressed rubber sheet is heated and pressurized so as to be closely attached to the protruding portions and the groove portions of the molding die. FIG. 5 shows a state in which the compressed rubber sheet is molded.
[0020]
First, as shown in FIG. 1, a base die 3 having a cylindrical mother die 2 having a projection 4 and a groove 5 alternately mounted on a die having a perfect circular cross section is prepared. After the coating is applied to the surface of the portion 4 and the groove portion 5, the reinforcing cloth 6 which has been subjected to the adhesive treatment or untreated is pulled out, sandwiched between the molding die 1 coated with the rubber-based adhesive and the pinion roll 7, and the molding metal is formed. While the mold 1 and the pinion roll 7 are rotated synchronously, the reinforcing cloth 6 is pulled out, pressed against the protruding portion 4 and the grooved portion 5 to form a mold, and after winding one to several plies, the reinforcing cloth 6 is cut by a cutter. This molding step is performed in an environment in which the molding die 1 is heated to room temperature or about 80 ° C.
[0021]
The rubber-based adhesive used here is obtained by blending in a rubber compound of the same type as the compressed rubber sheet 10 shown below, dissolving in a solvent such as methyl ethyl ketone (MEK), toluene and mixing. In addition, the reinforcing cloth 6 is securely molded.
[0022]
The reinforcing cloth 6 is made of cotton, polyester fiber, nylon, or the like, and is a cloth woven in a plain weave, a twill weave, a satin weave, or the like, and may be a wide-angle canvas in which the warp and the weft have a crossing angle of about 90 to 120 °. After the reinforcement cloth 4 is subjected to the RFL treatment, the rubber composition is subjected to fiction coating to obtain a canvas with rubber. The RFL solution is obtained by mixing a latex with an initial condensate of resorcinol and formaldehyde, and the latex used herein includes chloroprene, styrene-butadiene-vinylpyridine terpolymer, hydrogenated nitrile, NBR and the like.
[0023]
Subsequently, as shown in FIG. 2, both end surfaces of the unvulcanized compressed rubber sheet 10 having a predetermined thickness on which a compressed rubber layer is to be formed in advance are cut in a bias shape. After the compressed rubber sheet 10 is wound around the molding die 1 on which the reinforcing cloth 6 is formed and the cut surface 11 is abutted, the surface of the sheet 10 where the cut surface 11 is located is pressed with a pressing jig (not shown). After the joint is pressed lightly, the joint 13 is formed by applying heat and pressure using a heating press 12. The heating and pressing conditions are a temperature of 80 to 120 ° C., a surface pressure of 1 to ² kg / cm ² , and a time of 10 to 30 seconds.
[0024]
The rubber of the compressed rubber sheet 10 used here includes natural rubber, butyl rubber, styrene-butadiene rubber, chloroprene rubber, ethylene / α-olefin rubber, alkylated chlorosulfanized polyethylene (ACSM), and hydrogenated nitrile rubber (H -NBR), a rubber material such as a mixed polymer of a hydrogenated nitrile rubber and an unsaturated metal carboxylate, or a mixture thereof.
[0025]
The compressed rubber sheet 10 is made of aramid fiber, polyamide fiber, polyester fiber, cotton, or other fiber in rubber, and the length of the fiber varies depending on the type of fiber, but short fibers of about 1 to 10 mm are used. Aramid fibers of about 3 to 5 mm and polyamide fibers, polyester fibers and cotton of about 5 to 10 mm are used. When the direction of the short fibers in the rubber layer is 90 ° that is perpendicular to the longitudinal direction of the belt, most of the short fibers are oriented in the range of 70 ° to 110 °. It is desirable.
[0026]
As shown in FIG. 3, a resin film made of polymethylpentene or polyethylene terephthalate, which is an anti-adhesion material 15, having excellent heat resistance and mold release properties, is wound around the surface of the compressed rubber sheet 10 by one ply, overlapped and joined, The process proceeds to a molding step of the compressed rubber sheet 10.
[0027]
In the molding step, a vulcanizing can can be used. In this case, as shown in FIG. 4, a rubber jacket 17 which is a vapor barrier material is put on the outside of the anti-adhesive material 15, and then placed on the vulcanizing can. The mold is formed at a temperature of 160 to 180 ° C. and an external pressure of only 0.8 to 0.9 MPa for about 5 to 10 minutes to form an unvulcanized compressed rubber layer 20 as shown in FIG. Even if it is molded with a vulcanizing can, cracking of the joint portion 13 of the compressed rubber layer 20 does not occur. Needless to say, the molding can be performed by heating and pressing while pressing the outside of the compressed rubber sheet 10 with a pressing band instead of the vulcanizing can.
[0028]
FIG. 6 shows a state in which a belt molded body has been produced on the surface of the molded compressed rubber sheet. The molding die 1 is mounted on a molding machine (not shown), and polyester fiber, aramid fiber, glass fiber, etc. Is wound spirally, and an adhesive rubber sheet 31 forming an adhesive rubber layer, an expanded rubber sheet 33 forming an expanded rubber layer, and a reinforcing cloth 34 are sequentially wound to form a belt molded body 35. I do. Then, the molding die 1 taken out of the molding machine is set on a support table and a jacket (not shown) is fitted.
[0029]
The belt molded body 35 is transferred to a vulcanizer and vulcanized by a usual method. After vulcanization, the jacket and then the cylindrical belt sleeve are extracted from the cylindrical mother die 2 of the molding die 1, and the belt sleeve is cut into a predetermined width to form a transmission belt 40 which is a cogged belt as shown in FIG. Is prepared.
[0030]
The stretched rubber sheet 33 uses the same rubber composition as the compressed rubber sheet 10, and the adhesive rubber sheet 31 is the same as the compressed rubber sheet 10, and may include the above-mentioned short fibers, but preferably does not include it.
[0031]
The transmission belt 40 has a core 42 made of a cord of polyester fiber, aramid fiber, glass fiber, or the like embedded in an adhesive rubber layer 41, and an extension rubber including a reinforcing cloth 43 on the upper and lower parts of the adhesive rubber layer 41, respectively. It has a layer 44 as well as a compressed rubber layer 45 containing a reinforcing cloth 43. The compression rubber layer 45 is provided with cog portions 48 in which cog valley portions 46 and cog ridge portions 47 are alternately arranged at a constant pitch along the belt longitudinal direction. Of course, a cog portion can also be provided on the surface of the stretched rubber layer 44.
[0032]
【Example】
Hereinafter, the effects of the present invention will be confirmed by more specific examples.
[0033]
As a reinforcing cloth, a wide angle plain woven canvas using a 50:50 weight ratio of twisted yarn of aramid fiber (trade name: Twaron) and polyethylene terephthalate fiber was prepared, and the canvas was immersed in an RFL solution, and then immersed in 150 ° C. C. for 2 minutes, and then the chloroprene rubber composition was subjected to friction coating to obtain a canvas with rubber.
[0034]
A rubber composition composed of chloroprene rubber containing aramid short fibers was prepared for the compressed rubber sheet and the extended rubber sheet, and a rubber composition composed of chloroprene rubber containing short fibers also for the adhesive rubber layer. The thickness of the compressed rubber sheet is 6.6 mm, and the thickness of the stretched rubber sheet is 3.2 mm.
[0035]
As a core wire, 1,500 denier aramid fiber (trade name: Twaron) is twisted in the upside down direction at 19.7 turns / 10 cm and the bottom twist number 15.8 turns / 10 cm in the upside down direction, and 2 × 3 twist. An unprocessed cord having a total denier of 9,000 was prepared. Next, the untreated cord was pre-dipped with an isocyanate-based adhesive, dried at about 170 to 180 ° C., immersed in an RFL solution, and stretch-heat-set at 200 to 240 ° C. to obtain a treated cord.
[0036]
A cylindrical mold having alternating protrusions and grooves is provided on a spindle with a molding die fitted with a mold having a perfect circular cross section, and a rubber paste obtained by dissolving a chloroprene rubber composition with methyl ethyl ketone is used as the protrusion. The surface of the groove was sprayed and painted. Then, the reinforcing cloth was sandwiched between the molding die and the pinion roll, and two-ply lamination was performed while the molding die and the pinion roll were being molded while being rotated synchronously.
[0037]
Subsequently, a compressed rubber sheet whose end face was cut with a bias was wound on a reinforcing cloth of a molding die, butted against the end faces, and the joints were lightly joined with a stitcher. ２2 kg / cm 2 for 15 seconds).
[0038]
Then, a 0.05-mm-thick polymethylpentene film is wrapped around the surface of the compressed rubber sheet by one ply, further covered with a rubber jacket, placed in a vulcanizer in that state, and heated and pressurized (temperature: 170 ° C., The compressed rubber sheet was molded into the protruding portion and the groove portion of the cylindrical mother die by an external pressure of only 0.8 Mpa for about 7 minutes.
[0039]
Further, the core wire, the adhesive rubber sheet, and the stretched rubber sheet are sequentially wound to form a belt molded body, a jacket is covered, a molding die is set in a vulcanized can, and vulcanized under normal conditions to obtain a belt sleeve. Was. This sleeve was cut into a V shape by a cutter to complete a low-edge cogged belt for a scooter.
[0040]
In the obtained low-edge cogged belt, the position of the joint of the compressed rubber layer could not be specified on the appearance, no cracks occurred, the shape of the cog peak was uniform over the entire circumference, and at the overlap of the reinforcing cloth No wrinkles occurred. In the method of the present invention, there is a difference in heat history at the time of molding the compressed rubber sheet as compared with the conventional method, but even when measuring the adhesive force between the core wire and the adhesive rubber layer in the belt state, compared with the conventional belt. No difference was seen.
【The invention's effect】
As described above, in the invention described in the present application, the reinforcing cloth is sandwiched between a forming die having protrusions and grooves alternately and a pinion roll meshing with the protrusions and grooves. The mold and the pinion roll are molded while being rotated synchronously, and a compressed rubber sheet for forming a compressed rubber layer is wound around a molding die, the cut surfaces are butt-joined, and an anti-adhesive material is applied to the surface of the compressed rubber sheet. After winding, the compressed rubber sheet is heated and pressurized, and is closely attached to the protrusions and grooves of the molding die. In addition, cracking and wrinkling of the reinforcing cloth, which are defects due to insufficient volume of rubber at the joint, can be eliminated, and product quality can be stabilized, and it is necessary to prepare a cog pad in advance. Not for Enables reduction of work in process, there are excellent effects such as inlining production becomes possible.
[Brief description of the drawings]
FIG. 1 shows a step of molding a reinforcing cloth into a molding die in the production method of the present invention.
FIG. 2 shows a step of winding a compressed rubber sheet around a molding die and joining the cut surfaces in a butted manner in the production method of the present invention.
FIG. 3 shows a step of winding an anti-adhesive material around the surface of the compressed rubber sheet in the production method of the present invention.
FIG. 4 shows a step of heating and pressurizing the compressed rubber sheet to closely contact the protruding portion and the groove-shaped portion of the molding die in the production method of the present invention and molding the sheet.
FIG. 5 shows a state in which a sheet for compressed rubber is molded in the production method of the present invention.
FIG. 6 shows a state in which a belt molded body is formed on the surface of a compressed rubber sheet molded in the production method of the present invention.
FIG. 7 is a partial front view of a cogged belt obtained by the manufacturing method of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Molding die 2 Cylindrical mother die 3 Molding die 4 Protrusion part 5 Groove part 6 Reinforcement cloth 7 Pinion roll 10 Sheet for compression rubber 11 Cut surface 12 Heat press 13 Joint part 15 Anti-adhesive material 17 Jacket 20 Compressed rubber Layer 30 Core 31 Adhesive rubber sheet 34 Reinforcement cloth 35 Belt molding

Claims (5)

Manufacture of a power transmission belt in which at least a compression rubber layer of a compression rubber layer and an extension rubber layer has a cog portion in which cog peaks and cog valleys are alternately arranged, and a core wire is formed to be embedded in the adhesive rubber layer. In the method,
The reinforcing cloth is sandwiched between a molding die having a projection and a groove portion alternately and a pinion roll meshing with the projection and the groove portion, and the molding die and the pinion roll are molded while rotating synchronously,
A sheet for compressed rubber that forms a compressed rubber layer is wound around a molding die, the cut surfaces are butt-joined,
After wrapping an anti-adhesive material on the surface of the compressed rubber sheet, the compressed rubber sheet is heated and pressurized to form a projection and a groove of a molding die,
An unvulcanized compressed rubber sheet from which the anti-adhesive material has been removed is wrapped with an expanded rubber sheet that forms at least a core wire and an expanded rubber layer on the surface of the unvulcanized compressed rubber sheet to form a belt molded body, and then vulcanized. A method for manufacturing a power transmission belt, comprising cutting a sulfuric sleeve into a V shape to produce a power transmission belt. 2. The method according to claim 1, wherein after the rubber-based adhesive is applied to the surface of the molding die, the reinforcing cloth is interposed between the pinion roll and the projection and the groove of the molding die while being engaged therewith and rotated. Of manufacturing transmission belts. 3. The method for manufacturing a power transmission belt according to claim 1, wherein the end portions of the compressed rubber sheet are butted at a bias cut surface, and the joined portion is joined by heating and pressing. The method for producing a power transmission belt according to any one of claims 1 to 3, wherein the anti-adhesion material is at least one resin film selected from polymethylpentene and polyethylene terephthalate. An anti-adhesive material is wrapped around the surface of the compressed rubber sheet, the molding die covered with the jacket is placed in a vulcanizing can, and the compressed rubber sheet is heated and pressurized to apply the protrusions and grooves to the molding die. The method for manufacturing a power transmission belt according to claim 1, wherein the power transmission belt is molded by pressing.

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