JPH1190997A - Manufacture of toothed belt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To upgrade an external appearance by inserting a cylindrical canvas in which an insertion bar is inserted into a periphery of a mold with a groove so as to dispose the bar in the groove of the mold, fixedly mounting it, and then pressurizing it to manufacture a preform of the state that the canvas is forced together with the bar into the groove, thereby eliminating exudation of rubber from a joint part. SOLUTION: A mold 11 in which a jacked is engaged is introduced into a vulcanizing pan, heated, and pressurized. Then, a cylindrical canvas 1 is forced together with an insertion bar 10 into a groove 11 of the mold to manufacture a preform. Before the canvas in which the bar 10 is inserted is heated and pressurized, the bar 10 is projected from a surface of the mold 10, but after it is heated and pressurized, the projected bar 10 is pressurized by a pressing plate, and the canvas 1 is forced into the groove 12 of the mold. Thus, even if unvulcanized rubber flows into the groove in the next vulcanizing step, a joint part is not largely deformed. Thus, puncture fault for overflowing the rubber from the part scarcely occurs.

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 toothed belt, which can accurately set the position of a joint portion in a sewing-stitched cylindrical canvas, and eliminates the bleeding of rubber from the joint portion to improve the appearance. The present invention relates to a method for manufacturing a toothed belt which is excellent and prevents early cracking and sound generation from the joint.

[0002]

2. Description of the Related Art A conventional toothed belt is composed of a rubber compound using chloroprene as a raw material rubber on teeth and a back, and an RFL using SBR vinylpyridine latex as a latex component.
(Resorcinol / Formalin / Latex) A cover fabric used in the longitudinal direction of the belt using glass fiber cords or aramid fiber cords that have been adhesively treated with liquid as core wires, and crimped nylon as wefts.
Used as a belt for OHC driving (overhead cam driving) for automobiles.

[0003] The above-mentioned cover canvas generally has a joint portion, and a hot melt joint in which the ends of the canvas are heated and melted and joined together, or a method of joining with a sewing machine in order to increase the strength of the joint portion is adopted. ing. However, in the case of the toothed belt for driving the OHC, since the environmental temperature to be used becomes high due to the compact engine room and the use of FF, and the hot melt joint cannot withstand the strength sufficiently, the sewing machine joint is mainly used. Has become.

Further, when the sewing machine joint portion is located at a tooth valley portion or a corner portion of a tooth bottom, the sewing thread of the joint portion is greatly stretched and finally cut to open the canvas.
Cracks may occur. For this reason, the present applicant has improved this in Japanese Patent Publication No. Hei 3-18821.
In this method, a wire is inserted into a joint portion inside a cylindrical canvas sewn with a sewing machine, inserted and mounted in a mold, and after spinning a cord, the wire was removed,
A belt sleeve was produced by laminating an unvulcanized rubber thereon and vulcanizing it.

[0005]

However, in the case of a sewing machine joint, the strength of the sewing machine changes in the feed amount depending on the rigidity of the canvas and the state of the canvas surface when sewing. When these conditions change, the strength of the sewing may vary even under the same sewing condition.
And, even if the sewing was strong or weak, the toothed belt was defective.

[0006] For example, a cylindrical canvas having strong sewing has a shape in which a joint portion is protruded, and when this is used for manufacturing a toothed belt, the protruded portion of the joint portion is buried in the tooth portion. Early cracks occurred, causing early cracking failure during belt running.

On the other hand, when the sewing is weakened, the canvas located on the tooth surface of the mold does not move because it is pressed by the cord, but the sewing thread in the canvas in the groove is locally stretched by the flow of rubber, Unvulcanized rubber during the production of the toothed belt overflowed from this portion, so-called puncture failure occurred. The belt where this occurred generated a noise when the rubber contacted the pulley.

The present invention has been made in order to solve the above problems, and it is possible to accurately set the position of a joint portion in a sewing-stitched cylindrical canvas, and to eliminate the bleeding of rubber from the joint portion to improve the appearance. Further, it is an object of the present invention to provide a method for manufacturing a toothed belt in which early cracking and sound generation from the joint portion are prevented.

[0009]

That is, according to the first aspect of the present invention, a core wire is buried between a tooth portion provided at a predetermined interval along a longitudinal direction and a back portion provided on the opposite side. Then, in the method of manufacturing a toothed belt in which the surface of the tooth portion is covered with canvas, a step of inserting an insertion rod into a sewing-stitched joint located outside the cylindrical canvas, and a step of inserting the insertion rod into the cylindrical shape. After mounting the canvas on the mold such that the insertion rod is positioned in the mold groove, pressing the cylindrical canvas together with the insertion rod into the groove to produce a preform, and after removing the insertion rod, Spinning a cord made of cord on the preformed body, laminating unvulcanized rubber thereon, and vulcanizing and molding the unvulcanized rubber so as to flow into the groove to produce a belt sleeve, Of a toothed belt consisting of Lies in the way.

In the present invention, the cylindrical canvas into which the insertion rod is inserted is attached to the mold such that the insertion rod is positioned in the mold groove, and then the cylindrical canvas is pressed into the groove together with the insertion rod by pressing the cylindrical canvas into the groove. A step of producing a molded body is provided. In this preformed body, the canvas is pushed into the mold groove by the volume of the insertion rod. Therefore, even if unvulcanized rubber flows into the groove in the next vulcanization step, the joint does not deform significantly and does not receive a large force, so that the rubber overflows from this part and puncture defects are less likely to occur. Become.

In the invention according to the second aspect of the present invention, the production of the toothed belt in which the insertion rod is an elongated rigid body having a round cross section having an acute tip shape and inserted between the sewing thread of the sewing seam and the canvas. In the method, the insertion rod is easy to insert between the sewing thread of the sewing seam and the canvas, and the work is facilitated.

According to the third aspect of the present invention, the cylindrical canvas is inserted and mounted on the peripheral surface of the mold such that the insertion rod is positioned in the mold groove, and then the mold is put into a vulcanization can and the jacket is put on the jacket. The preform is prepared by heating and pressing. By applying external pressure with a jacket, a preform can be prepared by pushing the canvas into the mold groove by the volume of the insertion rod.

[0013] In the invention according to claim 4 of the present application, the cylindrical canvas into which the insertion rod is inserted is mounted on the mold such that the insertion rod is located in the mold groove, and the insertion rod is pressed by a press machine to form the cylindrical canvas. The preformed body can be manufactured by pushing it into the groove together with the canvas.

According to the fifth aspect of the present invention, a preform can be manufactured by heating and pressing the insertion rod with a press machine.

In the invention according to claim 6 of the present application, after the cylindrical canvas is mounted on the mold such that the insertion rod is positioned in the mold groove, the insertion rod is fitted into the through hole provided in the mold, and the mold is inserted into the mold. This is a method of manufacturing a toothed belt that is installed so as to be movable toward the bottom surface of the groove, particularly by inserting an insertion rod into a through hole provided in the mold and installing the insertion bar so as to be movable toward the bottom surface of the mold groove. In addition, the operation of aligning the joint portion of the cylindrical canvas sewn with the sewing machine with the mold groove can be performed reliably and quickly, and the insertion rod can be freely moved to the mold groove.

In the invention according to claim 7 of the present application, the strength of the sewing of the cylindrical canvas 1 measured by the resistance value when the insertion rod is pushed between the sewing thread of the sewing machine and the canvas is 1 to 1. In the method of manufacturing a 5kg toothed belt,
As a result, a puncture defect in which the rubber overflows from the joint portion is further reduced.

[0017]

1 to 10 show the steps of manufacturing a toothed belt according to the present invention. Figure 1
1 is a perspective view of a cylindrical canvas used. The cylindrical canvas 1 is made of a plain woven fabric, a twill woven fabric, a satin woven fabric or the like, and the weft 2 in the belt longitudinal direction is a polyamide fiber such as aramid fiber, 6 nylon, 6.6 nylon, 12 nylon, polyester fiber, polyvinyl alcohol fiber or the like. Although not particularly limited, yarns including multi-filament yarns of para-aramid fibers are particularly preferable. The multifilament yarn of the para-aramid fiber may include a yarn made of a meta-aramid fiber.

The specific configuration of the weft 2 is a twist of three types of yarns, namely, multifilament yarn of para-aramid fiber, spun yarn of meta-aramid fiber, and urethane elastic yarn. The other two types of weft yarns are composed of a multi-filament yarn of para-aramid fiber, an aliphatic fiber yarn (6 nylon, 6.6 nylon, polyester, polyvinyl alcohol, etc.), and a twist yarn of three types of urethane elastic yarn. May be done.

The warp yarn 3 of the cylindrical canvas 1 may be a filament yarn of aramid fiber composed of para-aramid fiber or meta-aramid fiber, polyamide such as 6 nylon, 6.6 nylon, 12 nylon, polyvinyl alcohol, polyester. And the like. Preferably, if a multifilament yarn in which the filament yarn of the aramid fiber is formed by converging the filament yarn of the para-aramid fiber to the weft 2 is used, the rigidity can be balanced and the cover canvas having a uniform thickness can be obtained.

The multifilament yarn of the para-aramid fiber is a multifilament yarn obtained by collecting a plurality of 0.3 to 1.2 denier filament raw yarns, or 0.3 to 1.2 denier. Is a multifilament yarn obtained by converging a plurality of filament raw yarns, for example, Kevlar, Technora, and Twaron. If the thickness of the filament yarn is less than 0.3 denier, the tensile strength of the cover canvas in the longitudinal direction of the belt decreases, and the abrasion resistance due to contact with the pulley decreases. On the other hand, if the thickness of the filament raw yarn exceeds 1.2 denier, the rigidity of the yarn in the direction in which the multi-filament yarn of para-aramid fiber is driven in the process of bonding the cover as a canvas after weaving. Since the warp and the weft as the canvas cannot be balanced, wrinkles are generated due to the uneven thickness of the cloth, and it cannot be used for a toothed belt which requires a uniform PLD value.

The weft in the longitudinal direction of the belt is 2
A multifilament yarn of 0 to 80% by weight of a para-aramid fiber is preferred. The reason for this is that if the content is less than 20% by weight, the tensile strength of the canvas in the longitudinal direction of the belt is reduced, and tooth breakage tends to occur when the belt runs under a high load. The reason for this is that the rigidity of the multifilament yarn in the driving direction becomes excessive as in the above reason, so that it is impossible to obtain a canvas having a uniform thickness.

The joint portion 4 is formed by abutting the ends of the cylindrical canvas 1 on a polyamide, polyester, polypropylene, or the like such as 6 nylon, 6.6 nylon, or 12 nylon.
Sewing is performed through a sewing thread 6 made of a twisted filament such as aramid or a monofilament thread.

The above-mentioned canvas 1 is previously treated with an RFL solution, an isocyanate solution or an epoxy solution. R
The FL solution is obtained by mixing a latex with an initial condensate of resorcinol and formalin, and the latex used here is styrene, butadiene, vinylpyridine terpolymer, hydrogenated nitrile rubber, chlorosulfonated polyethylene, epichlorohydrin. Such as latex.

The strength of the sewing of the cylindrical canvas 1 is measured by a resistance value of pushing an insertion rod between the sewing thread and the canvas of the sewing seam, and is usually of a size set in a range of 1 to 5 kg. Use This measuring method has a length of 200 mm such as stainless steel with a sharp needle at the tip.
~ 500mm, to measure the mechanical resistance value at the time of insertion using a sewing machine sewing strength measurement jig which is attached to the tension gauge by welding the insertion rod of diameter 1-3mm,
Specifically, the insertion rod is inserted between the sewing thread of the sewing stitch on the outer side of the cylindrical canvas and the canvas for about 100 to 400 mm, and the maximum value of the mechanical resistance value as the pushing pressure can be quantitatively measured by the tension gauge. . When the strength of the sewing machine is small, the mechanical resistance value is small, and when the strength of the sewing machine is large, the mechanical resistance value is large.

In the case of the present invention, when the mechanical resistance value is less than 1 kg, the sewing thread is stretched and unvulcanized rubber may overflow from the joint portion 4 during vulcanization molding,
On the other hand, if the resistance value exceeds 5 kg, the joint portion 4 will be protruded at the joint portion 4, and if this is used, the protruded portion of the joint portion 4 will be embedded in the tooth portion 21, and an early crack will occur from this portion. This causes cracking during belt running.

FIGS. 2 and 3 show a state in which the insertion rod 10 is inserted into the sewing-stitched joint portion 4 located outside the cylindrical canvas. The insertion rod 10 has an acute angle at its tip, a round elongated wire having a circular or elliptical cross section, or a rigid body such as a resin rod, and a sewing thread 6 and a canvas 1 on the outer side of the cylindrical canvas 1. And spans the entire width of the cylindrical canvas 1.

Although the insertion rod 10 has a cross-sectional area enough to penetrate the mold groove 12, the cross-sectional area is usually preferably 5 to 50% of the volume of the mold groove 12. 5
%, The cylindrical canvas 1 is pressed into the mold groove 12 together with the insertion rod 10 by heating and pressing to form the preform 8 as shown below, and the amount of deformation of the cylindrical canvas 1 is small, During vulcanization molding, the amount of deformation of the canvas due to the flow of rubber increases, and unvulcanized rubber may overflow from the joint portion 4. On the other hand, if it exceeds 50%, the insertion rod 10 is difficult to insert into the joint portion 4, and the outer sewing thread 6 is stretched, so that the joint portion 4 is easily deformed or cut.

FIG. 4 shows a state in which the cylindrical canvas 1 into which the insertion rod 10 is inserted is inserted into the mold 11 such that the insertion rod 10 is positioned in the mold groove 12. The insertion rod 10 can accurately position the joint 4 in the mold groove 12. In particular, in order to accurately fix the position of the cylindrical canvas 1, through holes 15 are arranged at regular intervals in the flange portion 13 of the mold 11 as shown in FIG. 5, and the end of the insertion rod 10 is inserted into the through hole 15. What is necessary is just to insert and lock. The through hole 15 has such a size that the insertion rod 10 can move toward the bottom surface of the mold groove 12.

FIG. 6 shows a state in which the jacket 17 is fitted into the mold 11 on which the cylindrical canvas 1 with the insertion rod 10 is mounted. The mold 11 in which the jacket 17 is fitted is put into a vulcanizing can, and heated and pressed to insert the cylindrical canvas 1 into the insertion rod 10.
At the same time, the preform 8 is manufactured by being pushed into the mold groove 12. As shown in FIG. 7, before the cylindrical canvas 1 into which the insertion rod 10 is inserted is heated and pressurized, the insertion rod 10 protrudes from the surface of the mold 11. The protruding insertion rod 10 is the jacket 1
7 presses the cylindrical canvas 1 into the mold groove 12.

The heating and pressurizing condition is that the temperature is 150 to 165.
° C, time is 5 to 10 minutes, and external pressure is 3 to 15 kg / cm ² . The heating and pressurization is required to facilitate the thermal deformation of the cylindrical canvas 1 and to make the adhesive or rubber attached to the obtained preform 8 uncured or unvulcanized. When the adhesive or rubber attached to the preform 8 is cured or vulcanized,
This is because adhesion to unvulcanized rubber flowing into the mold groove 12 during vulcanization molding is deteriorated.

When the mold 11 is removed from the vulcanizing can, the mold 11 is cooled from the inside of the mold 11 with a cooling medium such as water.
Withdraw the insertion rod 10.

As means for pushing the insertion rod 10,
As shown in FIG. 11, heated press plate 2 of press machine 20
1 can be abutted against the insertion rod 10 and pressed uniformly.
That is, as shown in FIG. 7, before the cylindrical canvas 1 into which the insertion rod 10 is inserted is heated and pressed, the insertion rod 10 protrudes from the surface of the mold 11, but after being heated and pressed as shown in FIG. Then, the protruding insertion rod 10 is pressed by the press plate 18 to push the cylindrical canvas 1 into the mold groove 12.

The heating and pressing conditions are as follows:
° C, time is 1 to 5 minutes, external pressure is 0.5 to 10 kg / cm ²
It is. Heating and pressurization facilitates thermal deformation of the cylindrical canvas 1,
It is necessary to make the adhesive or rubber adhered to the obtained preform 8 uncured or unvulcanized. This is because, when the adhesive or rubber attached to the preform 8 is cured or vulcanized, adhesion to unvulcanized rubber flowing into the mold groove 12 during vulcanization molding is deteriorated.

Of course, the insertion rod 10 can be pushed into the mold groove 12 together with the cylindrical canvas 1 at room temperature without heating.

Mold 1 on which preform 8 is mounted
9, after a glass fiber cord or an aramid fiber cord forming a core wire 21 is spirally wound thereon and an unvulcanized rubber 24 forming a tooth portion 22 and a back portion 23 is laminated thereon, as shown in FIG. This is covered with a jacket and vulcanized in a vulcanizing can. During the vulcanization molding, the rubber flows into the mold groove 12 together with the cylindrical canvas 1 by the flow of rubber,
Create a belt sleeve. After removing the vulcanized belt sleeve from the mold 11, the vulcanized belt sleeve is attached to two shafts of a cutting machine, and cut to a predetermined width by a cutter while applying tension and rotating, thereby producing a toothed belt 20.

Examples of the unvulcanized rubber 24 include hydrogenated nitrile rubber, hydrogenated nitrile rubber obtained by adding a metal salt of an unsaturated carboxylic acid, chlorosulfonated polyethylene (CSM), and alkylated chlorosulfonated rubber. Rubbers having improved heat aging resistance, such as polyethylene (ACSM) and chloroprene rubber, are preferred. The hydrogenated nitrile rubber has a hydrogenation rate of 80% or more, and preferably 90% or more in order to exhibit heat resistance and ozone resistance.
A hydrogenated nitrile rubber having a hydrogenation rate of less than 80% has extremely low heat resistance and ozone resistance.

FIG. 10 is a side view of the toothed belt according to the present invention. The toothed belt 20 has a plurality of tooth portions 22 and a core wire 21 made of glass fiber cord or aramid fiber cord embedded along the belt longitudinal direction. With the back 23
The cylindrical canvas 1 is adhered to the surface of the tooth portion 22, the joint portion 4 of the canvas 1 does not largely enter the tooth portion 22, and the sewing thread 6 is not extended.

[0038]

The present invention will be described below in detail with reference to examples. Example 1 A 200 denier filament yarn obtained by converging a 1.5 denier para-aramid fiber filament yarn into a warp yarn and a weft (Technola 200D / 2 yarns, Conex 30th yarn and spandex 140D / 1 yarn) ) And weft (Technola 200D / 1),
Weaving texture (110 warp / 5cm, weft 120 / 5cm)
Was woven. After weaving, the canvas is vibrated in water to shrink it to about 1/2 the width at the time of weaving, and then the hydrogenated nitrile rubber compound is dissolved in methyl ethyl ketone and immersed in a processing solution to which isocyanate has been added. It was dried to give a 0.9 mm treated canvas. The canvas used the weft direction in the longitudinal direction of the belt.

After cutting the above treated canvas to a predetermined length,
The ends of the canvas were butted, a 6-nylon monofilament thread was used as a sewing thread, and the feed rate of the canvas was adjusted to produce a cylindrical canvas 1. And the cylindrical canvas 1
2.5 mm in diameter between the sewing thread 6 and the canvas 1 outside the
An insertion rod 10 made of a 1200 mm long wire was inserted.

As a core wire 21, about 200 glass fiber filaments having a strand diameter of about 9 μm, which are melt-spun and surface-treated with a silane coupling agent, are bundled to form a strand.
The three strands are aligned and immersed in the RFL solution,
After drying at 30 ° C. for 2 minutes and baking at 250 to 300 ° C. for 2 minutes, a ply twisted yarn twisted in the S direction at about 12 times / 10 cm and a plied twist yarn twisted in the Z direction the same number of times. Got ready.

Next, 13 twisted yarns in the S direction are aligned and
Glass fiber cord twisted in the Z direction at a rate of about 8 turns / 10 cm, and 13 twisted lower twisted yarns are similarly arranged in the same direction, and glass fibers having a twist number of 8 turns / 10 cm in the S direction. Code. Then, in order to adhere the RFL-treated glass fiber cord to the back, the teeth, and the cloth,
Further, the rubber composition was dissolved in a solvent, immersed in an overcoat solution to which isocyanate was added, and dried to produce a glass fiber cord to be a cord.

In the production of the toothed belt, the cylindrical canvas 1 into which the insertion rod 10 has been inserted is inserted into the mold 11 so that the insertion rod 10 is positioned in the mold groove 12, and is mounted thereon. This was put into a vulcanizing can, heated and pressurized at an external pressure of 9.0 kg / cm ² at a temperature of 153 ° C. for 10 minutes, then the mold 11 was taken out of the vulcanizing can, and the inside of the mold 11 was cooled with water. A preform 8 was produced.

After inserting the insertion rod 10 from the cooled mold 11 and spinning the glass fiber cord on the preform 8, a rubber sheet made of a hydrogenated nitrile rubber compound was further wound. Subsequently, this was vulcanized in a conventional manner, and the obtained vulcanized belt sleeve was cut into a predetermined width to obtain individual belts. Belt size is 105
S8M19 (Belt tooth type: STPD type, number of teeth: 1
05, belt width: 19.1 mm, tooth pitch: 8 mm). As a result of an appearance inspection of the joint portions 4 of the plurality of toothed belts obtained, no exudation of rubber was observed in any of the belts.

In addition, the running time until the toothed belt was chipped when the toothed belt was running under a high load was measured. The driving test machine used here is a driving pulley (21 teeth), a driven pulley (21 teeth),
And it consists of three axes of idler pulley (21 teeth)
A toothed belt was wound around these pulleys, and the number of meshing teeth with the driven pulley was set to six. In this manner, the running time until the toothed belt was chipped at an ambient temperature of 120 ° C., a rotation speed of the driving pulley of 6,000 rpm, and a load of the driven pulley of 7 hp was measured. As a result, the running time leading to tooth loss was 490 hours on average.

COMPARATIVE EXAMPLE 1 The insertion rod 10 was inserted into the joint 4 inside the cylindrical canvas 1, and the cylindrical canvas 1 was inserted into the mold 11 so that the insertion rod 10 was positioned in the mold groove 12 and mounted. Thereafter, the insertion rod 10 was pulled out, the same glass fiber cord as in the example was spun on the canvas 1, and a rubber sheet made of a hydrogenated nitrile rubber compound was further wound. Subsequently, this was vulcanized in the same manner as in the example, and the obtained vulcanized belt sleeve was cut into a predetermined width to obtain individual belts. Inspection of the joints of a plurality of toothed belts obtained from the belt sleeve revealed that the joints of some of the belts were slightly darkened and rubber bleeding was observed. In addition, the running time leading to tooth loss was 400 hours on average.

As a result, in the example, even in the appearance inspection, the joint portion of the canvas did not largely penetrate into the tooth portion, and the sewing thread was stretched and no rubber bleeding was observed. Further, even when the toothed belt of the embodiment is run under a high load,
No cracks were seen from the joints, indicating that the running time leading to tooth chipping was also improved.

Example 2 A cylindrical canvas 1 in which the same insertion rod 10 as in Example 1 was inserted.
And the glass fiber cord used as a core wire was produced. In manufacturing the toothed belt, the cylindrical canvas 1 into which the insertion rod 10 is inserted is used.
Is inserted into the mold 11 so that the insertion rod 10 is positioned in the mold groove 12, and is then mounted on the insertion rod 1 by a press machine 20 having a press plate 21 adjusted to a temperature of 153 ° C.
0 was heated and pressed to produce a preform 8.

After inserting the insertion rod 10 from the cooled mold 11, spinning the glass fiber cord on the preform 8, a rubber sheet made of a hydrogenated nitrile rubber compound was further wound. Subsequently, this was vulcanized in a conventional manner, and the obtained vulcanized belt sleeve was cut into a predetermined width to obtain individual belts. Belt size is 105
S8M19 (Belt tooth type: STPD type, number of teeth: 1
05, belt width: 19.1 mm, tooth pitch: 8 mm). As a result of an appearance inspection of the joint portions 4 of the plurality of toothed belts obtained, no exudation of rubber was observed in any of the belts.

Example 3 After inserting the cylindrical canvas 1 into which the insertion rod 10 was inserted and inserting it into the mold 11 so that the insertion rod 10 was located in the mold groove 12, the insertion rod 10 was moved to room temperature by a press machine at room temperature. To produce a preform 8. After removing the insertion rod 10 from the mold 11 and spinning the glass fiber cord on the preform 8, a rubber sheet made of a hydrogenated nitrile rubber compound was further wound. Subsequently, this was vulcanized in a conventional manner, and the obtained vulcanized belt sleeve was cut into a predetermined width to obtain individual belts. Belt size is 105S8M19 (Belt tooth shape: STP
D type, number of teeth: 105, belt width: 19.1 mm, tooth pitch: 8 mm). As a result of an appearance inspection of the joint portions 4 of the plurality of toothed belts obtained, no exudation of rubber was observed in any of the belts.

Comparative Example 2 The insertion rod 10 was inserted into the joint 4 inside the cylindrical canvas 1, and the cylindrical canvas 1 was inserted into the mold 11 so that the insertion rod 10 was positioned in the mold groove 12, and was mounted. Thereafter, the insertion rod 10 was pulled out, the same glass fiber cord as in the example was spun on the canvas 1, and a rubber sheet made of a hydrogenated nitrile rubber compound was further wound. Subsequently, this was vulcanized in the same manner as in the example, and the obtained vulcanized belt sleeve was cut into a predetermined width to obtain individual belts. Inspection of the joints of a plurality of toothed belts obtained from the belt sleeve revealed that the joints of some of the belts were slightly darkened and rubber bleeding was observed.

[0051]

As described above, according to the first aspect of the present invention, the step of inserting the insertion rod into the sewing-stitched joint located outside the cylindrical canvas, and the step of inserting the insertion rod into the cylindrical canvas Is inserted into the mold such that the insertion rod is positioned in the mold groove, and then the cylindrical canvas is pressed together with the insertion rod into the groove to produce a preform, and a preliminary step is performed after removing the insertion rod. Spinning a cord made of cord on a molded body, laminating unvulcanized rubber thereon, and vulcanizing and molding such that the unvulcanized rubber is poured into the groove to produce a belt sleeve. In the method of manufacturing a toothed belt, in particular, after inserting the cylindrical canvas into which the above-mentioned insertion rod is inserted, inserting the insertion rod into the peripheral surface of the grooved mold so that the insertion rod is positioned in the groove of the mold, and mounting and fixing the same, The cylinder Canvas is provided a process of making a preform in the state pushed into the groove together with the insertion bars,
Therefore, even if unvulcanized rubber flows into the groove during the next vulcanization process, the joint does not deform significantly and does not receive a large force.
This has the effect that puncture failure is less likely to occur.

In the invention according to the second aspect of the present invention, the insertion rod is an elongated rigid body having a round cross section having an acute tip end shape, and a toothed belt inserted between a sewing thread and a canvas of a sewing seam is manufactured. In the method, the insertion rod can be easily inserted between the sewing thread of the sewing seam and the canvas, which has an effect of facilitating the work.

According to the third aspect of the present invention, the cylindrical canvas is inserted and mounted on the peripheral surface of the mold so that the insertion rod is positioned in the mold groove, and then the mold is put into a vulcanizing can and jacketed. The preform is produced by heating and pressurizing. By applying external pressure with a jacket, there is an effect that the preform can be produced by pushing the canvas by the volume of the insertion rod into the mold groove.

According to the fourth aspect of the present invention, the cylindrical canvas into which the insertion rod is inserted is mounted on the mold so that the insertion rod is positioned in the mold groove, and the insertion rod is pressurized by a press to form the cylindrical canvas. The preformed body can be manufactured by pushing it into the groove together with the canvas.

According to the fifth aspect of the present invention, a preform can be easily produced by heating and pressing the insertion rod with a press machine.

In the invention according to claim 6 of the present application, after the cylindrical canvas is mounted on the mold such that the insertion rod is positioned in the mold groove, the insertion rod is fitted into the through hole provided in the mold, and the mold is inserted into the mold. This is a method of manufacturing a toothed belt that is installed so as to be movable toward the bottom surface of the groove, particularly by inserting an insertion rod into a through hole provided in the mold and installing the insertion bar so as to be movable toward the bottom surface of the mold groove. The positioning work of positioning the joint of the cylindrical canvas sewn on the sewing machine in the mold groove can be performed reliably and quickly, and furthermore, the insertion rod can be freely moved to the mold groove. There is.

In the invention according to claim 7 of the present application, the sewing strength of the cylindrical canvas 1 measured by the resistance value when the insertion rod is pushed between the sewing thread of the sewing machine and the canvas is 1 to 1. In the method of manufacturing a 5kg toothed belt,
As a result, there is an effect that rubber spillover from the joint portion and puncture failure are less likely to occur.

[Brief description of the drawings]

FIG. 1 is a perspective view of a sewing-stitched cylindrical canvas used in the method for manufacturing a toothed belt according to the present invention.

FIG. 2 is a view showing a state in which an insertion rod is inserted into a joint located outside a cylindrical canvas sewn on a sewing machine.

FIG. 3 is an enlarged view of a joint part shown in FIG. 2;

FIG. 4 is a front view showing a state in which the cylindrical canvas into which the insertion rod is inserted is inserted into the grooved mold such that the insertion rod is positioned in the mold groove.

FIG. 5 is a partially enlarged view of a flange portion of a grooved mold having a through hole.

FIG. 6 is a front view showing a state in which a jacket is fitted into a grooved mold on which a cylindrical canvas into which an insertion rod is inserted is mounted.

FIG. 7 is a partially enlarged view of a grooved mold groove portion before heating and pressurizing a cylindrical canvas into which an insertion rod is inserted.

FIG. 8 is a partially enlarged view of a grooved mold groove portion after heating and pressing a cylindrical canvas into which an insertion rod is inserted.

FIG. 9 is a cross-sectional view of a grooved mold showing a state in which an unvulcanized rubber is laminated after spinning a cord made of cord on a preform.

FIG. 10 is a side view of a toothed belt obtained by the method of the present invention.

FIG. 11 is a partially enlarged view showing a state where a preform is being molded.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylindrical canvas 4 Joint part 6 Sewing thread 8 Preform 10 Insertion rod 11 Mold 12 Mold groove part 13 Flange 15 Through hole 17 Jacket 21 Core wire 24 Unvulcanized rubber

Continued on the front page (51) Int.Cl. ⁶ Identification code FI B29L 29:00

Claims (7)

[Claims] 1. A toothed belt having a core wire buried between a tooth portion provided at a predetermined interval along a length direction and a back portion provided on the opposite side thereof, and a surface of the tooth portion is covered with canvas. In the manufacturing method, a step of inserting the insertion rod into a sewing-stitched joint located outside the cylindrical canvas, and mounting the cylindrical canvas into which the insertion rod is inserted into the mold such that the insertion rod is positioned in the mold groove. Then, pressurizing and pressing the cylindrical canvas together with the insertion rod into the groove to produce a preform, and after removing the insertion rod, spinning a cord made of cord on the preform, Forming a belt sleeve by laminating unvulcanized rubber thereon and vulcanizing and molding the unvulcanized rubber so as to flow into the groove. 2. The method for manufacturing a toothed belt according to claim 1, wherein the insertion rod is an elongated rigid body having a round cross-section having an acute-angled tip, and is inserted between the sewing thread and the canvas of the sewing seam. 3. A cylindrical canvas into which an insertion rod is inserted is inserted and mounted on the peripheral surface of the mold so that the insertion rod is positioned in the mold groove, and then the mold is put into a vulcanization can and heated and pressed by a jacket. The method for producing a toothed belt according to claim 1, wherein the preformed body is produced by using the method. 4. A cylindrical canvas into which an insertion rod has been inserted is mounted on a mold such that the insertion rod is positioned in a mold groove.
The method for producing a toothed belt according to claim 1, wherein the insertion rod is pressurized by a press machine and pressed into a groove together with a cylindrical canvas to produce a preform. 5. The method according to claim 4, wherein the insertion rod is heated and pressed by a press machine. 6. A cylindrical canvas is mounted on a mold such that an insertion rod is positioned in a mold groove, and then the insertion rod is fitted into a through hole provided in the mold, and is moved toward the bottom of the mold groove. The method for producing a toothed belt according to claim 1, wherein the belt is installed as possible. 7. A sewing machine according to claim 1, wherein the sewing strength of the cylindrical canvas 1 is 1 to 5 kg as measured by a resistance value when the insertion rod is pushed between the sewing thread of the sewing machine and the canvas. Manufacturing method of toothed belt.