JP3371075B2 - Method of manufacturing toothed belt - Google Patents

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, in which a tooth portion having an accurate external appearance appears and air remaining in the tooth portion cut from both ends of a vulcanized belt sleeve is removed. It is to provide a method for manufacturing a toothed belt.

[0002]

2. Description of the Related Art A conventional toothed belt is an RFL containing a rubber compound containing chloroprene as a raw material rubber on its teeth and back and an SBR vinyl pyridine latex as a latex component.
(Resorcin / formalin / latex) is composed of glass fiber cords or aramid fiber cords that have been adhesively treated with liquid as core wires, and a cover canvas used in the longitudinal direction of the belt as crimped nylon wefts,
It is used as a belt for OHC drive (overhead cam drive) for automobiles.

In the above-mentioned method for producing a toothed belt, a cover canvas, a core wire, and an unvulcanized rubber sheet are usually laminated on a mold, covered with a jacket, placed in a vulcanizing can, and heated and pressed. Release the vulcanization sleeve from the mold,
After the back surface of the sleeve was polished, it was cut into a predetermined width.

As another method for manufacturing a toothed belt,
After laminating the cover canvas, the core wire, and the unvulcanized rubber sheet on the mold, cover it with a jacket, place it in a vulcanizing can, heat and pressurize it, cast the unvulcanized rubber into the groove, and mold it, A method for cooling a mold, laminating another unvulcanized rubber sheet on it, and vulcanizing it to produce a belt is disclosed in Japanese Patent Publication No. 2-500009.

Further, the above-mentioned cover canvas generally has a joint part, and a hot melt joint for joining the ends of the canvas by heating and melting, and a method of jointing with a sewing machine to increase the strength of the joint part are adopted. ing. In the case of the OHC driving toothed belt, the environment temperature to be used becomes high due to the downsizing of the engine room and the formation of FF, and the hot melt joint cannot sufficiently withstand the strength, so that it is mainly used.

In the sewing machine joint, when the joint portion is located at the root portion or the corner portion of the root, the sewing thread of the joint portion is greatly stretched, and finally cut to open the canvas and crack. There was something that happened. For this reason, the applicant improved this in Japanese Patent Publication No. 3-18821. In this method, a wire is inserted into the joint on the inside of a cylindrical canvas sewn with a sewing machine, this is inserted and mounted in a mold, the cord is spun, then the wire is pulled out, and unvulcanized rubber is laminated on it. Then, the belt sleeve was produced by vulcanizing.

[0007]

The conventional method for manufacturing a toothed belt has the advantage that the steps of molding and vulcanization are simple and mass production is easy, but on the other hand, the core in which unvulcanized rubber is aligned by spinning is used. Since it is poured from the gap between the wires, there is a problem that the press-fitting time is long.

Further, the air existing in the groove portion of the mold escapes from the upper position and the lower position of the mold in order as the rubber is pressed and flowed in. The press-fitting of the mold groove is completed from the center of the mold to both ends, and the press-fitting of both ends is the last, so the vulcanization sleeve is cut into a specified width, especially the both ends of the sleeve. The belt cut from the part had a slight occurrence of air remaining on the side surface of the cut tooth part. Further, the belt cut from this portion had a tooth height lower than that of a regular belt and had poor appearance with no gloss on the surface of the canvas.

The above problems occur as the mold surface length becomes longer, the press-fitting time becomes shorter, the rubber viscosity becomes higher, and the core wire pitch becomes denser. It will be easier.

On the other hand, in the case of the sewing machine joint part, the strength of the sewing machine sewing is changed by the stiffness of the canvas and the state of the surface of the canvas when the sewing machine is sewn, when the feed amount changes (change of slip ratio). It is easy to change, and when these states change, the strength of the sewing machine may vary even under the same sewing conditions. Even if the sewing was strong or weak, the toothed belt was defective.

For example, in the case of a cylindrical canvas which is strongly sewn, the joint portion has a protruding shape, and when this is used for manufacturing a toothed belt, the protruding portion of the joint portion is embedded in the tooth portion, and from this portion. Early cracks were generated, which was a cause of early cracking defects when the belt was running.

On the other hand, when the sewing becomes weak, 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 groove is locally stretched by the rubber flow, Unvulcanized rubber during the manufacture of the toothed belt overflowed from this portion, so-called puncture failure occurred. In the belt where this occurred, a sound was produced when the rubber contacted the pulley.

The present invention has been made to solve the above problems, and mainly allows the appearance of teeth having an accurate appearance and removes air remaining in the cut teeth from both ends of the vulcanized belt sleeve. It is to provide a method for manufacturing a toothed belt. In addition, the position of the joint in the sewing machine sewn cylindrical canvas can be set accurately, the teeth can appear accurately, and the exudation of rubber from the joint can be eliminated to improve the appearance. It is an object of the present invention to provide a method for manufacturing a toothed belt that prevents early cracking and pronunciation.

[0014]

That is, in the invention according to claim 1 of the present application, a core wire is embedded between a tooth portion provided at a predetermined interval along the length direction and a back portion provided on the opposite side thereof. In the method for manufacturing a toothed belt in which the surface of the tooth portion is covered with canvas, the insertion rod is sewn on the outside of the cylindrical canvas by sewing.
Inserted into the joint part and the above insertion rod.
Inserted cylindrical canvas, the insertion rod is located in the mold groove
And the volume of the mold groove
Or unvulcanized with a thickness corresponding to less than that
The step of winding the rubber sheet on this, the step of heating and pressing the mold around which the cylindrical canvas and the unvulcanized rubber sheet are wound, and press-fitting the cylindrical canvas and the unvulcanized rubber sheet into the mold groove, and the above insertion After pulling out the rod, spinning the core wire, further laminating an unvulcanized rubber sheet forming a back portion on this, and vulcanizing and molding these unvulcanized rubber to produce a belt sleeve. In the manufacturing method of the toothed belt, the residual air is reduced because the unvulcanized rubber is press-filled into the mold groove portion in advance, and the belt cut from both ends of the sleeve does not have air remaining in the tooth portion. In addition, the surface of the canvas has a good gloss and the appearance is normal.

[0015]

Further, according to the present invention, since the cylindrical canvas in which the insertion rod is inserted is mounted on the mold so that the insertion rod is located in the mold groove portion, the position of the joint portion does not change during molding, and the tooth portion does not change. By arranging the joint portion on the surface, it is possible to prevent early cracking and sounding from the joint portion.

In the invention according to claim 2 of the present application, the toothed material is blended such that the unvulcanized rubber sheet press-fitted into the mold groove portion and the unvulcanized rubber sheet forming the back portion have different rubber physical properties after vulcanization. In the belt manufacturing method, the rubber physical properties of the teeth and the back, for example, rubber hardness, can be changed according to the purpose.

In the invention according to claim 3 of the present application, the mold is wrapped around the cylindrical canvas and the unvulcanized rubber sheet, the jacket is covered, and the jacket is placed in a vulcanizing can. This is a method for manufacturing a toothed belt, in which patterning can be reliably performed.

In the invention according to claim 4 of the present application, after the cylindrical canvas is mounted on the mold so that the insertion rod is located in the mold groove, the insertion rod is fitted into the through hole provided in the mold, and the mold is molded. This is a method for manufacturing a toothed belt that moves toward the bottom surface of the groove, and in particular, by sewing the sewing machine by inserting the insertion rod into the through hole provided in the mold so that it can move toward the bottom surface of the mold groove. The work of aligning the joint portion of the cylindrical canvas with the mold groove portion can be surely and quickly performed, and the insertion rod can be freely moved to the mold groove portion.

[0020]

1 to 8 show the steps of manufacturing a toothed belt according to the present invention. Among them, FIG. 1 is a perspective view of a cylindrical canvas used. This cylindrical canvas 1
Is a plain woven fabric, a twill woven fabric, a satin woven fabric, etc., and the weft yarns 2 in the belt longitudinal direction are aramid fibers, polyamide fibers such as 6 nylon, 6.6 nylon and 12 nylon, polyester fibers, polyvinyl alcohol fibers, etc. and are not particularly limited. However, among them, a yarn containing a multi-filament yarn of para-aramid fiber is preferable. The para-aramid fiber multifilament yarn may include a yarn made of meta-aramid fiber.

The specific construction of the weft yarn 2 is a multi-filament yarn of para-aramid fiber, a spun yarn of meta-aramid fiber, and a urethane elastic yarn, which are three kinds of yarns. In addition, the other two weft yarns are obtained by plying three types of yarns of para-aramid fiber multifilament yarn, aliphatic fiber yarn (6 nylon, 66 nylon, polyester, polyvinyl alcohol, etc.) and urethane elastic yarn. But it's okay.

As the warp yarns 3 of the cylindrical canvas 1, filament yarns of aramid fibers composed of para-aramid fibers and meta-aramid fibers, polyamides such as 6 nylon, 6.6 nylon and 12 nylon, polyvinyl alcohol, polyester. Etc. consists of filament yarn. Preferably, when the aramid fiber filament yarn is a multifilament yarn in which the para-aramid fiber filament raw yarn is bundled with the weft yarn 2, rigidity is balanced and a cover canvas having a uniform thickness is obtained.

The para-aramid fiber multifilament yarn is a multifilament yarn in which a plurality of filament raw yarns of 0.3 to 1.2 denier are gathered together 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 this filament raw yarn is less than 0.3 denier, the tensile strength of the cover canvas in the belt longitudinal direction will decrease, and the abrasion resistance due to contact with the pulley will be poor. On the other hand, when 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 adhering as the cover canvas after weaving Is too large, the warp and weft as the canvas cannot be balanced, and wrinkles occur due to uneven cloth thickness, which cannot be used for a toothed belt that requires a uniform PLD value.

Further, the total amount of weft yarns in the longitudinal direction of the belt is 20 to
A multifilament yarn of which 80% by weight is para-aramid fiber is preferable. The reason for this is that if it is less than 20% by weight, the tensile strength of the canvas in the longitudinal direction of the belt is lowered, and tooth breakage is likely to occur during belt running under high load.
This is because if the content exceeds 10% by weight, the rigidity of the multifilament yarn of para-aramid fiber in the driving direction becomes excessively similar to the above reason, and it becomes impossible to obtain a canvas having a uniform thickness.

The joint portion 4 is made by abutting the ends of the cylindrical canvas 1 with each other, and is made of polyamide such as 6 nylon, 6.6 nylon and 12 nylon, polyester, polypropylene,
A filament twisted yarn such as aramid, and a sewing thread 6 made of a monofilament yarn are sewn together.

The canvas 1 is pretreated with an RFL solution, an isocyanate solution or an epoxy solution. R
The FL solution is a mixture of latex with an initial condensate of resorcin and formalin, and the latex used here is styrene. butadiene. It is a latex of vinyl pyridine terpolymer, hydrogenated nitrile rubber, chlorosulfonated polyethylene, epichlorohydrin and the like.

The sewing strength of the cylindrical canvas 1 is measured by the resistance value of pushing the insertion rod between the sewing thread of the sewing seam and the canvas, and the size is usually set in the range of 1 to 5 kg. To use. This measurement method uses a length of 200 such as stainless steel with a sharp needle tip.
The mechanical resistance value at the time of insertion is measured by using a sewing machine sewing strength measuring jig in which an insertion rod having a diameter of 500 mm and a diameter of 1 to 3 mm is welded to a tension gauge.
Specifically, the inserting rod is inserted between the sewing thread of the sewing machine seam on the outside of the cylindrical canvas and the canvas for about 100 to 400 mm, and the maximum mechanical resistance value, which is the pressing pressure, can be quantitatively measured with a tension gauge. . When the sewing strength of the sewing machine is small, the mechanical resistance value is small. On the contrary, when the sewing strength of the sewing machine is large, the mechanical resistance value is large.

In the case of the present invention, if the mechanical resistance value is less than 1 kg, the sewing thread may be stretched and unvulcanized rubber may overflow from the joint portion 4 during vulcanization molding.
On the other hand, when the resistance value exceeds 5 kg, the joint portion 4 is in the form of being bulged, and when this is used, the bulging portion of the joint portion 4 is embedded in the tooth portion 21 and early cracking occurs from this portion. , There will be cracks when running the belt.

2 and 3, the insertion rod 10 is attached to the cylindrical canvas 1.
The state is shown in which the sewing machine is inserted into the sewing machine sewn joint portion 4 located on the outside. The insertion rod 10 is made of metal or synthetic resin having rigidity such as a round elongated wire such as a circular shape or an elliptical shape with a sharp tip, and the sewing thread 6 of the sewing seam on the outside of the cylindrical canvas 1 And the canvas 1, and spans the entire width of the cylindrical canvas 1.

The insertion rod 10 has a cross-sectional area that allows it to sufficiently penetrate into the mold groove portion 12, but the cross-sectional area is usually preferably less than 30% of the volume of the mold groove portion 12. Three
When it is 0% or more, the insertion rod 10 becomes difficult to pull out from the joint portion 4, the sewing thread 6 is stretched, and the joint portion 4
Deformation and disconnection are likely to occur.

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

In the next step, as shown in FIG. 6, the unvulcanized rubber sheet 17 is molded together with the cylindrical canvas 1 into the mold groove portion 12.
It is a step of pressing into and molding. Specifically, an unvulcanized rubber sheet 17 having a thickness corresponding to the volume of the mold groove 12 or a volume less than that is wrapped around this, and a jacket 18 is put on the unvulcanized rubber sheet 17, and this is put in a vulcanization can. Install and heat and press to mold. It is preferable that the unvulcanized rubber sheet 17 has a thickness equal to the volume of the mold groove portion 12, or a thickness corresponding to at least 1/3 of the volume of the mold groove portion 12. 1
If it is less than / 3, it becomes impossible to perform sufficient patterning.

The condition of heating and pressurization is that the temperature is 150 to 165.
C., time 2-4 minutes, external pressure 5-10 kg / cm @ 2. Heating and pressurization is the flow of unvulcanized rubber sheet and cylindrical canvas 1
Molding is performed in the mold groove portion 12 by facilitating thermal deformation of.

As shown in FIG. 8, the mold 11 subjected to the above-mentioned patterning has a glass fiber cord or an aramid fiber cord forming a core wire 21 spirally wound thereon, and a tooth portion 22 and a back portion 23 are formed. After stacking the unvulcanized rubber sheet 24, a jacket is put on the unvulcanized rubber sheet 24 and the sheet is placed in a vulcanizing can for vulcanization. During the vulcanization molding, a part of the unvulcanized rubber sheet 24 is poured into the mold groove portion 12 to manufacture a belt sleeve. After the vulcanized belt sleeve is extracted from the mold 11, the vulcanized belt sleeve is attached to two shafts of a cutting machine, and while being applied with tension and rotated, it is cut into a predetermined width by a cutter to produce a toothed belt 20.

Of course, in the present invention, the cylindrical canvas 1 without the insertion rod 10 can be used. Also in this case, similarly to the above, after mounting the cylindrical canvas 1 on the mold 11, the unvulcanized rubber sheet 17 having a thickness corresponding to the volume of the mold groove portion 12 or less is wound around this. The mold 1 in which the cylindrical canvas 1 and the unvulcanized rubber sheet 17 are wound is heated and pressed to press the cylindrical canvas 1 and the unvulcanized rubber sheet 17 into the mold groove 12, and the core wire 21 is spun. Further, an unvulcanized rubber sheet 24 forming a back portion is further laminated thereon, and these unvulcanized rubbers are integrally vulcanized and molded to form a belt sleeve, which is cut into a predetermined width to form a toothed belt. 20 is produced.

The above-mentioned unvulcanized rubber sheets 17 and 24 include hydrogenated nitrile rubber, hydrogenated nitrile rubber to which a metal salt of unsaturated carboxylic acid is added, chlorosulfonated polyethylene (CSM), alkylated. Rubbers having improved heat aging resistance such as chlorosulfonated polyethylene (ACSM) and chloroprene rubber are preferable. still,
Hydrogenated nitrile rubber has a hydrogenation rate of 80% or more,
90% to exhibit heat resistance and ozone resistance
The above is good. A hydrogenated nitrile rubber having a hydrogenation rate of less than 80% has extremely low heat resistance and ozone resistance.

Further, the rubber physical properties of the unvulcanized rubber sheets 17 and 24 can be changed according to the purpose. For example, the rubber hardness of the unvulcanized rubber sheet 17 corresponding to the tooth portion is increased, and the rubber hardness of the unvulcanized rubber sheet 24 corresponding to the back portion is made smaller than that, or the unvulcanized rubber sheet 17 is reduced.
Can be made better than that of the unvulcanized rubber sheet 24. Further, the colors of the unvulcanized rubber sheets 17 and 24 may be changed, and the unvulcanized rubber sheet 17 may be mixed with short fibers arranged in the width direction or the longitudinal direction of the belt.

FIG. 9 is a side view of the toothed belt according to the present invention. In the toothed belt 20, a plurality of tooth portions 22 and a core wire 21 made of a glass fiber cord or an aramid fiber cord are embedded along the belt longitudinal direction. The cylindrical canvas 1 is attached to the surface of the tooth portion 22, and the joint portion 4 of the canvas 1 does not largely enter the tooth portion 22.
Also, the sewing thread 6 is not stretched.

[0039]

EXAMPLES The present invention will be described in detail below with reference to examples. Example 1 A filament yarn of 200 denier in which filament raw yarn of para aramid fiber of 1.5 denier was bundled into a warp of a canvas, and a weft yarn (Technora 200D / 2 yarns, Conex 30th count and spandex 140D / 1 yarn) Naru) and weft (Technola 200D / 1 thread)
Texture of weaving (warp 110/5 cm, weft 120/5 cm)
A 2/2 twill canvas made of was woven. After weaving, the canvas was vibrated in water to shrink it to about 1/2 the width at the time of weaving, and then the hydrogenated nitrile rubber composition was dissolved in methyl ethyl ketone and immersed in a treatment liquid containing isocyanate, It was dried to give a treated canvas of 0.9 mm. The canvas used the weft direction in the longitudinal direction of the belt.

After cutting the above treated canvas to a predetermined length,
Cylindrical sailcloth 1 was produced by abutting the ends of the sailcloth, using 6-nylon monofilament thread as the sewing thread, and adjusting the feeding speed of the sailcloth. And the cylindrical canvas 1
2.5 mm between the sewing thread 6 and the canvas 1 on the outside of the
An insertion rod 10 made of a wire having a length of 1200 mm was inserted.

As the core wire 21, about 200 glass fiber filaments having a diameter of about 9 μm which are melt-spun and surface-treated with a silane coupling agent are bundled into a strand,
Align the 3 strands and immerse them in the RFL solution,
After drying at 30 ° C. for 2 minutes and baking at 250 to 300 ° C. for 2 minutes, a lower twisted yarn twisted in the S direction at a twist of about 12 times / 10 cm and a lower twisted yarn twisted in the Z direction at the same number of times were prepared. .

Next, 13 ply-twisted yarns in the S direction are lined up,
A glass fiber cord in which the upper twist is twisted in the Z direction at a rate of about 8 times / 10 cm, and 13 Z twisted lower twisted yarns are similarly drawn in the same direction, and the glass fiber is twisted 8 times / 10 cm in the S direction. I used the code. Then, in order to bond the RFL-treated glass fiber cord to the back, teeth and tooth cloth,
Further, the rubber composition was dissolved in a solvent, immersed in an isocyanate-added overcoat liquid, and dried to produce a glass fiber cord serving as a cord.

In the production of the toothed belt, the cylindrical canvas 1 having the insertion rod 10 inserted therein is inserted into the mold 11 so that the insertion rod 10 is positioned in the mold groove portion 12, and then mounted, and then the volume of the mold groove portion 12 is increased. An unvulcanized rubber sheet 17 having a thickness of 1.6 mm and having a thickness corresponding to the above was wound on this, a jacket was put on it, and this was placed in a vulcanizing can and heated and pressed. The conditions were a temperature of 153 ° C., a time of 3 minutes, and an external pressure of 7 kg / cm 2.

After removing the insertion rod 10 from the molded mold 11 and spinning the above glass fiber cord thereon, the unvulcanized rubber made of a hydrogenated nitrile rubber compound having a thickness of 1.0 mm corresponding to the spine 23 is further formed. The sheet 24 was wrapped. Subsequently, this is heated at a temperature of 153 ° as usual.
C., 20 minutes, vulcanized at an external pressure of 9.0 kg / cm @ 2, and the obtained belt sleeve was cut into a predetermined width to obtain individual belts. The belt size is 105S8M19 (belt tooth type: STPD type, number of teeth: 105, belt width: 1
9.1 mm, tooth pitch: 8 mm). The toothed belt cut from both ends of the belt sleeve did not have air remaining in the tooth, and the surface of the canvas was glossy and the appearance was normal. Further, as a result of visual inspection of the joint portions of the obtained plural toothed belts, no bleeding of rubber was observed in any of the belts, and it was present at a predetermined position.

Example 2 After inserting the cylindrical canvas 1 into which the insertion rod 10 is inserted into the mold 11 so that the insertion rod 10 is located in the mold groove portion 12 and mounting it, about 2/3 of the volume of the mold groove portion 12 is set. An unvulcanized rubber sheet 17 having a thickness of 1.6 mm, which corresponds to the above, was wrapped around this, a jacket was put on it, and this was placed in a vulcanization can and heated and pressed. The conditions are temperature 153
° C, time 7 minutes, pressure 3 minutes.

Remove the insertion rod 10 from the mold 11,
After spinning the above glass fiber cord thereon, an unvulcanized rubber sheet 24 made of a hydrogenated nitrile rubber compound and having a thickness of 1.0 mm was further wound. Subsequently, this was kept at a temperature of 153 ° C. for 20 minutes and an external pressure of 9.0 kg as usual.
The belt sleeve obtained was vulcanized at a pressure of / cm @ 2 and cut into a predetermined width to obtain individual belts. Belt size is 1
05S8M19 (Belt tooth type: STPD type, number of teeth: 105, belt width: 19.1 mm, tooth pitch: 8 m
m). The toothed belt cut from both ends of the belt sleeve did not have air remaining in the tooth, and the surface of the canvas was glossy and the appearance was normal.

[0047]

As described above, in the invention according to claim 1 of the present application, the insertion rod is sewn on the outside of the cylindrical canvas.
The process of inserting it into the joint
Insert the wrapped cylindrical canvas with the insertion rod in the mold groove.
The mold, and the groove in the mold.
Unloaded with a thickness equivalent to the product or less
The process of wrapping the rubber vulcanizate sheet on this, and the cylindrical canvas
And a mold wrapped with an unvulcanized rubber sheet
The cylindrical canvas and unvulcanized rubber sheet in the mold groove.
The process of press fitting, and after removing the insertion rod,
An unvulcanized rubber sheet that is pinned and the back is formed on top of it.
Sheet, and vulcanize these unvulcanized rubbers.
In the method for manufacturing a toothed belt, which comprises a step of manufacturing a belt sleeve by pre-pressing the unvulcanized rubber into the groove of the mold in advance, air remains less and the belt is cut from both ends of the sleeve. No air remains in the teeth, and the surface of the canvas is glossy and the appearance is normal.

Further, since the cylindrical canvas with the above-mentioned insertion rod inserted therein is attached to the mold so that the insertion rod is located in the mold groove, the position of the joint does not change during molding, and the joint is attached to the tooth surface. effect may be to prevent premature cracking or sound from the joint portion by arranging the Ru Oh.

In the invention according to claim 2 of the present application, the unvulcanized rubber sheet press-fitted into the mold groove portion and the unvulcanized rubber sheet forming the back portion are compounded such that the rubber physical properties after vulcanization are different from each other. In the belt manufacturing method, the rubber physical properties of the tooth portion and the back portion can be changed according to the purpose. For example, the rubber hardness of the tooth portion can be increased and the rubber hardness of the back portion can be reduced as compared with that.

In the invention according to claim 3 of the present application, the mold is wrapped around the cylindrical canvas and the unvulcanized rubber sheet, the jacket is covered, and the jacket is placed in a vulcanizing can. This is a method of manufacturing a toothed belt, which has an effect of reliably performing patterning.

In the invention according to claim 4 of the present application, after the cylindrical canvas is mounted on the mold so that the insertion rod is located in the mold groove, the insertion rod is fitted into the through hole provided in the mold, and the mold is molded. This is a method for manufacturing a toothed belt that moves toward the bottom surface of the groove, and in particular, by sewing the sewing machine by inserting the insertion rod into the through hole provided in the mold so that it can move toward the bottom surface of the mold groove. The positioning work for aligning the joint portion of the cylindrical canvas with the mold groove portion can be performed reliably and quickly, and further, the insertion rod can be freely moved to the mold groove portion.

[Brief description of drawings]

FIG. 1 is a perspective view of a sewing machine sewn cylindrical canvas used in a 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 portion located outside a cylindrical canvas which is sewn with a sewing machine.

FIG. 3 is an enlarged view of a joint portion shown in FIG.

FIG. 4 is a front view showing a state in which a cylindrical canvas with an insertion rod inserted therein is inserted into a grooved mold so that the insertion rod is located in a mold groove portion.

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

FIG. 6 is a view showing a state in which a mold is wrapped around a cylindrical canvas and an unvulcanized rubber sheet and a jacket is put over the mold.

FIG. 7 is a partially enlarged view showing a state where the joint portion is modeled.

FIG. 8 is a cross-sectional view of a mold showing a state in which a core wire made of a cord is spun on a molded mold, and unvulcanized rubber is laminated on the molded mold.

FIG. 9 is a side view of the toothed belt obtained by the method of the present invention.

[Explanation of symbols]

1 Cylindrical canvas 4 joint section 8 Preform 10 insertion rod 11 Mold 12 Mold groove 17 Unvulcanized rubber sheet 21 core wire 24 Unvulcanized rubber sheet

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B29D 29/08

Claims (4)

(57) [Claims] 1. A toothed belt in which a cord is embedded between a tooth portion provided at a predetermined interval along the length direction and a back portion provided on the opposite side, and the surface of the tooth portion is covered with canvas. In the manufacturing method, the step of inserting the insertion rod into the sewing machine sewn joint located on the outer side of the cylindrical canvas, and the cylindrical canvas in which the insertion rod is inserted are attached to the mold so that the insertion rod is located in the mold groove. And the step of winding an unvulcanized rubber sheet having a thickness equivalent to or less than the volume of the mold groove, and heating the mold around which the cylindrical canvas and the unvulcanized rubber sheet are wound. A step of pressing the cylindrical canvas and the unvulcanized rubber sheet into the mold groove, and spinning the core wire after removing the insertion rod, and further laminating an unvulcanized rubber sheet forming a back portion on the core wire. Then Method for producing a toothed belt, comprising the steps, to produce a vulcanization molding to belt sleeve these unvulcanized rubber Te. 2. The production of a toothed belt according to claim 1, wherein the unvulcanized rubber sheet press-fitted into the mold groove portion and the unvulcanized rubber sheet forming the back portion are blended so as to have different rubber physical properties after vulcanization. Method. 3. A jacketed to mold wound cylindrical fabric and unvulcanized rubber sheets, according to claim 1 or performs an embossed unvulcanized state heating and pressing installed on a vulcanizer this
Or the method for manufacturing a toothed belt according to item 2 . 4. A cylindrical canvas is mounted on a mold so that the insertion rod is located in the mold groove, and then the insertion rod is fitted into a through hole provided in the mold and moved toward the bottom surface of the mold groove. The method for manufacturing a toothed belt according to claim 1 .