JP2000094541A - Preparation of belt with gear teeth on both paces - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for preparing a belt with gear teeth on both faces wherein accuracy on length of the belt is improved by stabilizing a pitch line of a core line and accurate shapes of the teeth are generated and time for molding can be shortened. SOLUTION: A method for preparing a belt with gear teeth on both faces consists of a premolding process wherein after a laminated body of a gear teeth fabric 5 and an unvulcanized rubber sheet is semi-vulcanized and embossed on the outer peripheral face of a mold with channels, a premolded body is formed by spinning a core wire 6, a vulcanization process wherein a prevulcanized molded body 8 is formed by heating and pressing under a condition where a release paper is wound on the surface of the premolded body, and a final embossing and vulcanization process wherein by heating and pressing a belt-like molded body 9 prepd. by laminating an unvulcanized rubber sheet 4' and a gear teeth fabric 5' on the prevulcanized molded body taken out from the mold with channels in a press mold with the same shapes of gear teeth with a definite pitch on its top and bottom bases, a top gear teeth part is embossed and vulcanized to form the belt with gear teeth on both faces.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a double-sided toothed belt, which reduces the number of forming steps, stabilizes the pitch line of the core wire, improves the length accuracy, and forms a precise tooth shape. The present invention relates to a method for manufacturing a double-sided toothed belt that can be used.

[0002]

2. Description of the Related Art A double-sided toothed belt having teeth on both sides has a plurality of upper teeth and lower teeth arranged along the length direction.
A cord is interposed between the upper teeth and the lower teeth, and the surface of the upper and lower teeth is covered with a cloth, and is used for office equipment, OA equipment, and transport equipment. It has become.

A method of manufacturing this double-sided toothed belt is disclosed in, for example, Japanese Patent Publication No. 6-43106, in which a tooth cloth is wound along the outer peripheral surface of a grooved mold, and a core wire is spirally wound thereon. , And further wrap an unvulcanized rubber sheet and a similar tooth cloth thereon, and heat and press the thus obtained belt molded body to produce a semi-vulcanized preformed body,
The preform taken out of the grooved mold is hung on two toothed pulleys whose axial distance can be adjusted, and the preform is heated and pressed by a press die composed of a pair of upper and lower toothed molds to form upper teeth. And vulcanizing the lower teeth and moving the vulcanized part to repeat the vulcanization of the next tooth.

As another method, Japanese Patent Publication No.
As disclosed in Japanese Patent No. 695, a tooth cloth is wound along the outer peripheral surface of a grooved mold, a core wire is spirally wound thereon, and an unvulcanized rubber sheet is further wound thereon. The obtained belt molded body was heated and pressurized to prepare a vulcanized preformed body, and the back rubber of this preformed body was polished leaving a rubber layer of 0.2 mm or less so that the core wire was not exposed, The step of laminating an unvulcanized rubber sheet and a tooth cloth thereon and heating and pressurizing with a mold were performed.

[0005]

However, in the above-described method for manufacturing a double-sided toothed belt, the semi-vulcanized preform has only one side formed with a tooth portion. In order to form the portion, a pressing die requires a larger pressing force and a longer time, and in some cases, vulcanization proceeds excessively and an accurate tooth profile is hardly produced. In addition, in the method of polishing the back rubber of the vulcanized preform, a polishing step is added, and polishing requires much time because polishing accuracy is required.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. The present invention improves the belt length accuracy by stabilizing the pitch line of the cords, and also allows an accurate tooth profile to appear, and reduces the molding time. An object of the present invention is to provide a method for manufacturing a double-sided toothed belt that can be shortened.

[0007]

That is, according to the first aspect of the present invention, a plurality of upper teeth and lower teeth are arranged along the longitudinal direction, and the upper teeth and the lower teeth are connected to each other. In a method of manufacturing a double-sided toothed belt in which a core wire is interposed between the upper and lower tooth portions and the surfaces of the upper and lower tooth portions are coated with a tooth cloth, a laminate of the tooth cloth and an unvulcanized rubber sheet is formed on the outer peripheral surface of the grooved mold. A pre-molding step of forming a pre-formed body by spinning the core wire after semi-vulcanizing and shaping the lower teeth, and pre-vulcanizing by applying heat and pressure with the release paper wound on the surface of the pre-formed body Vulcanization process to form a body,
Then, the belt-shaped molded body obtained by laminating the unvulcanized rubber sheet and the tooth cloth on the pre-vulcanized molded body taken out from the grooved mold is heated and pressed by a press die having the same tooth shape at a constant pitch on the upper and lower plates. Thus, there is provided a method of manufacturing a double-sided toothed belt comprising a final shaping vulcanizing step of forming and vulcanizing the upper teeth portion to form a double-sided toothed belt. The spinning of the wire eliminates the drop or misalignment of the core wire, stabilizes the pitch line of the core wire, improves the belt length accuracy, and improves the meshing of the teeth.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for manufacturing a double-sided toothed belt according to the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing a state before molding in which a tooth cloth and an unvulcanized rubber sheet are sequentially laminated on a grooved mold in a method for manufacturing a double-sided toothed belt,
FIG. 2 is a cross-sectional view of a preformed body showing a state in which a core is spun after a laminate is molded in a grooved mold (not shown).

In these figures, first, a grooved mold 1 is shown.
Is mounted on a molding machine (not shown), and an expandable and contractible tubular tooth cloth 5 is wound along the outer peripheral surface of the grooved mold 1 having the groove portions 2 and the tooth portions 3, and one side thereof is placed thereon. An unvulcanized rubber sheet 4 having a capacity to form a (lower tooth portion) is wound around a non-vulcanized rubber sheet 4, a release paper coated with a silicon-based material is wound around the surface, a rubber jacket is covered, and then put in a heating can. After semi-vulcanizing at a predetermined temperature and pressure to mold the lower teeth into a grooved mold, the core wire 6 is spirally wound under a constant tension, and preformed in a semi-vulcanized state as shown in FIG. The body 7 is formed. In addition, the spinning tension of the core wire 6 is
Also, since the unvulcanized rubber sheet 4 is molded into a grooved mold, it can be reduced to about half of the conventional size.

Thereafter, the same kind of release paper as above is wound around the surface of the pre-cured body 7 in the semi-vulcanized state, covered with a rubber jacket, and the lower teeth are vulcanized by a known vulcanization method. And the grooved mold 1 taken out of the vulcanizing can
The pre-vulcanized molded body 8 on which the lower teeth are formed is removed from.
As shown in FIG. 3, an unvulcanized rubber sheet 4 'having a predetermined thickness corresponding to the tooth rubber on the other side (upper tooth portion) and a tooth cloth 5' are newly wound around the pre-vulcanized molded body 8. Thus, an unvulcanized belt-shaped molded body 9 having a vulcanized lower tooth side and an unmolded upper tooth side is formed, and the process proceeds to the next final vulcanization step.

In the final molding and vulcanizing step, the belt-shaped molded body 9 is hung on two toothed pulleys 20 capable of adjusting the distance between the shafts as shown in FIG. The upper teeth 11 are molded and vulcanized by clamping and pressing by a temperature-adjustable press die 22 having molds 21 and 21. In this step, the upper teeth 11 can be accurately formed at the corresponding positions of the lower teeth 12, and the upper and lower PLD values can be matched.

The toothed mold 21 is, as shown in FIG.
The knock pins 24 are provided at diagonal positions on both ends of the lower board 23, while the pin insertion holes 2 are provided on the upper board 25 at positions opposed to the knock pins 24.
The position of the upper tooth portion 11 and the lower tooth portion 12 is prevented by fitting the knock pin 24 into the pin insertion hole 26. A plurality of adjustment plates 27 for adjusting the thickness of the belt to adjust the uniform PLD value are inserted and fixed to the knock pins 26.

When the upper teeth 11 and the lower teeth 12 are formed after the final molding, the press mold 22 is once removed, and then the toothed pulleys 20 and 20 are rotated to form the next upper teeth 11. By repeating the molding, a double-sided toothed belt 10 having upper teeth 11 and lower teeth 12 above and below the core wire 6 shown in FIG.
Is obtained.

The raw rubber used for the unvulcanized rubber sheet 4 includes heat aging resistance such as hydrogenated nitrile rubber, chloroprene rubber, chlorosulfonated polyethylene (CSM), and alkylated chlorosulfonated polyethylene (ACSM). Rubber, natural rubber, styrene butadiene rubber, nitrile rubber and the like are used. Among the above rubbers, as compounding agents, carbon black, zinc white, stearic acid, a plasticizer, an antioxidant, etc. are added, and as a vulcanizing agent, there are sulfur and organic peroxides. The vulcanizing agent is not particularly limited.

The core wire 6 is obtained by twisting filaments of 5 to 9 μm of E glass or high-strength glass and treating them with a rubber compound protecting agent or RFL liquid as an adhesive. . Further, as an organic fiber, a filament of 0.5 to 2.5 denier of a para-aramid fiber (trade name: Kevlar, Technora) having a small elongation with respect to stress and a large tensile strength is twisted, and an RFL solution, an epoxy solution A twisted cord treated with an adhesive of an isocyanate solution and a rubber compound is used. However, the present invention is not limited to these.

The canvas used as the tooth cloth 5 is 6 nylon, 66 nylon, polyester, aramid fiber or the like, and may be used alone or in combination. Warp (belt width direction) and weft (belt length direction) of tooth cloth 5
Is a filament yarn or a spun yarn of the above-mentioned fiber, and the woven structure may be any of a plain woven fabric, a twill woven fabric, and a satin woven fabric. In addition, it is preferable to use a part of urethane elastic yarn having elasticity as the weft.

The tooth cloth 5 is treated only with the RFL liquid, and the RFL liquid obtained by drying the RFL liquid has a solid content of 10 to 50% by weight. Is preferred. The solid content of the RFL solution is composed of the solid content of the RF resin and the latex. This is because the rubber oozing out on the surface of the tooth portion is scattered as rubber powder while the belt is running. This RFL solution was prepared by mixing an initial condensate of resorcinol and formalin with latex, and the molar ratio of resorcinol to formalin was 1: 1 to 1
3. Further, the weight percentage ratio of the latex of the initial condensate of resorcinol and formalin is 1: 1 to 10.
The latex used here is a latex such as styrene-butadiene-vinylpyridine terpolymer, hydrogenated nitrile rubber, chlorosulfonated polyethylene, epichlorohydrin and the like.

As a specific processing method of the tooth cloth 5,
The canvas is immersed in the RFL liquid, dipped with a pair of rolls at a squeezing pressure of about 0.3 to 0.8 kgf / cm (gauge pressure), dried, and then the RFL liquid is similarly applied.
The solid content of the RFL solution adhering to the canvas was adjusted to 10 to 50% by weight. If the solid content of the RFL liquid is less than 10% by weight, the contact portion between the warp and the weft of the canvas is easy to move, and the opening is enlarged, and the rubber of the tooth portion 2 is removed from the opening 8 of the tooth cloth. May be exposed to the surface of the part. On the other hand, when the solid content of the RFL liquid exceeds 50% by weight,
There is a problem that the amount of solid content increases and the shape of the tooth portion of the belt does not appear accurately.

On the inner surface of the tooth cloth 5 treated with the RFL solution,
A rubber paste obtained by dissolving a rubber composition mainly composed of raw rubber used for both upper and lower teeth in a solvent is coated by a spreading process (coating process) and dried at a temperature of 100 to 160 ° C. for 30 to 60 seconds. Thus, a rubber layer having a thickness of 0.1 to 0.3 mm is formed. If the thickness of the rubber layer is less than 0.1 mm, the unvulcanized rubber sheet will seep to the surface of the tooth cloth during press vulcanization, and if it exceeds 0.3 mm, the unvulcanized rubber sheet will have a tooth cloth surface. Although the bleeding to the side is prevented, the upper and lower PLD values are different. This is because this rubber layer is deformed in order to wind the core wire 6 around the rubber layer of the lower tooth cloth 5. In addition, the tooth cloth 5 coated on the surfaces of the upper and lower teeth portions.
It is preferable to coat the rubber layer 6 on the inner surface of the substrate in order to make the upper and lower PLD values coincide.

The above-mentioned semi-vulcanization refers to a state where each physical property value reaches 1 to 5% when each physical property value such as tensile strength, modulus and elongation at the time of optimum vulcanization is 100. . In this case, as a guide at the time of optimal vulcanization, the tensile strength is a point slightly above the maximum value, the modulus is a point slightly before the maximum value, and the elongation is a point slightly before the minimum value. It is determined from the curve.

[0021]

The present invention will be specifically described below with reference to examples. Example 1 A weft composed of 210 denier 66 nylon and a 200 denier wooly 6 nylon having a warp density of 150 (lines / 5 cm) and a weft density of 200 (lines / 5)
cm) after weaving into a 2/2 twill canvas, shrinking the fabric to about 1/2 the width at the time of weaving by applying vibration in water,
The canvas is immersed in the RFL solution, and 0.5 kgf is applied to a pair of rolls.
/ Cm (gauge pressure) and then dried. Subsequently, a rubber paste was applied to the inside of the treated tooth cloth with a doctor knife to a thickness of 0.2 mm and dried to form a rubber layer.

Next, a strand is formed by bundling glass fiber filaments having a wire diameter of about 9 μ as a core wire, and this strand is immersed in an RFL solution and dried at 250 ° C. for 2 minutes. It is a cord composed of about 600 filaments having a twist number of 10 cm. The diameter of this cord is about 1.2 mmφ.

The above-mentioned tooth cloth is finished into an endless cylindrical body, which is set in a grooved mold, and a 1.0 mm-thick rolled sheet made of a chloroprene rubber compound is wound thereon, and a predetermined temperature and pressure are applied. After shaping the lower teeth portion in a semi-vulcanized state, a pair of glass fiber cords S and Z are wound therefrom at an air pressure of 0.5 MPa so as to be alternately arranged at a spinning pitch of 2.5 mm. The coated release paper was wound around the jacket and the grooved mold was placed in a vulcanized can. After vulcanization by an ordinary vulcanization method, the pre-vulcanized molded product was removed from the grooved mold. A rolled sheet of chloroprene rubber compound having a thickness of 1.4 mm is wrapped around the pre-vulcanized molded product, and a flat tooth cloth treated in the same manner as described above is wrapped, and the lower teeth are vulcanized and the upper teeth are molded. An unvulcanized belt-shaped molded body was produced.

Next, the belt-shaped molded body is hung on two toothed pulleys whose axial distance can be adjusted, and the belt-shaped molded body is heated and pressurized by a press die composed of a pair of upper and lower toothed molds. After molding and vulcanizing the tooth portion, the toothed pulley was rotated to move the vulcanized portion, and the formation of the next upper tooth portion was repeated to obtain a double-sided toothed belt. The obtained belt had a belt tooth shape: DS8M and the number of teeth: 200
Tooth, belt width: 20 mm. The shape of the belt teeth after molding and vulcanization was good, the upper teeth and the lower teeth were at the same position, and the PLD values of the upper and lower sides were also consistent.

[0025]

As described above, in the invention according to the first aspect of the present invention, the laminate of the tooth cloth and the unvulcanized rubber sheet is semi-vulcanized on the outer peripheral surface of the grooved mold to perform preliminary molding. After that, a preforming step of spinning the core wire to form a molded body, a vulcanizing step of vulcanizing by heating and pressing with a release paper wound on the surface of the molded body, and a vulcanized belt-shaped molded body By heating and pressing a belt-shaped laminated body on which an unvulcanized rubber sheet and a tooth cloth are laminated with a press die having the same tooth shape at a fixed pitch on the upper and lower plates, the upper teeth are molded and vulcanized. In particular, since the core wire is spun after being molded in a semi-vulcanized state, the pitch line of the core wire is stabilized, the belt length accuracy is improved, and the meshing of the teeth is improved. Also, since the spinning tension is only half that of the conventional case, the molded product can be easily removed from the mold, and the productivity is further improved because no polishing is performed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one of the steps according to the manufacturing method of the present invention, showing a state in which a laminate is formed on the outer peripheral surface of a grooved mold.

FIG. 2 is a partial cross-sectional view of a semi-vulcanized preform obtained by semi-vulcanizing the laminate of FIG. 1 to mold a lower tooth portion and winding a core wire.

FIG. 3 is a partial cross-sectional view of a belt-shaped formed body according to the manufacturing method of the present invention.

FIG. 4 is a cross-sectional view showing a final molding vulcanization step according to the production method of the present invention, in which a belt-shaped molded body whose upper teeth are unvulcanized is heated and pressed.

FIG. 5 is an exploded perspective view of a press die used in the final molding and vulcanizing step of FIG. 4;

FIG. 6 is a partial cross-sectional view of a double-sided toothed belt according to the manufacturing method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Grooved mold 2 Groove part 3 Teeth part 4 Unvulcanized rubber sheet 5 Tooth cloth 6 Core wire 7 Preformed body 8 Prevulcanized formed body 9 Belt shaped body 10 Double-sided toothed belt 11 Upper toothed part 12 Lower toothed part 21 Toothed mold 22 Press mold

Continued on the front page F term (reference) 4F202 AA29 AA45 AD04 AD15 AD16 AG03 AG17 AH81 CA09 CB01 CB11 4F213 AA29 AA45 AD04 AD15 AD16 AG03 AG17 AH81 WA04 WA15 WA52 WA53 WA83 WA87 WB01 WB11

Claims (1)

[Claims] 1. A plurality of upper teeth and lower teeth arranged along the length direction, a core wire is interposed between the upper teeth and lower teeth, and surfaces of the upper and lower teeth are provided. In the method for manufacturing a double-sided toothed belt coated with a tooth cloth, the laminated body of the tooth cloth and the unvulcanized rubber sheet is semi-vulcanized on the outer peripheral surface of the grooved mold, and the lower teeth portion is shaped, and then the core wire is spinned A pre-molding step of forming a pre-molded body, a vulcanizing step of forming a pre-vulcanized molded body by applying heat and pressure with a release paper wound on the surface of the pre-formed body;
Then, the belt-shaped molded body obtained by laminating the unvulcanized rubber sheet and the tooth cloth on the pre-vulcanized molded body taken out from the grooved mold is heated and pressed by a press die having the same tooth shape at a constant pitch on the upper and lower plates. A method for producing a double-sided toothed belt, comprising a final molding vulcanizing step of forming and vulcanizing the upper teeth portion to form a double-sided toothed belt.