JP2001038820A - Production of belt with double-face tooth and belt with tooth - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce defective engagement and to improve flexural fatigue resisting properties by a method in which a cylindrical body having belt teeth on the inner surface is inserted between first and second press dies, the distance between both dies is reduced, the body is heated/pressurized, the belt teeth are formed on the outer surface of the body, and rubber is vulcanized. SOLUTION: On the circumferential surface of a cylindrical die 31 having a lot of tooth-shaped grooves, the first nylon canvas 32, glass core wire 33, a CR composition 34, and the second nylon canvas 35 are laminated in turn to do preliminary molding/vulcanization, and a cylindrical body 37 having belt teeth on the inner surface is formed. Next, the belt teeth of the inner surface of the body 37 are engaged with the tooth-shaped grooves of the first plate- shaped press die 38 having tooth-shaped grooves on the surface, the second press die 39 having tooth-shaped grooves on the surface is pressed to the outer surfaces of the body 37, and preliminary heating is done. The belt teeth are formed on the outer surface of the body 37 by pressing. In the preliminary heating, the fluidity of rubber is increased, and the crushing of the wire 33 by force from the rubber is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a double-sided toothed belt and a toothed belt.

[0002]

2. Description of the Related Art As a toothed belt, there is a double-sided toothed belt in which belt teeth are provided at equal pitches on both an inner peripheral surface and an outer peripheral surface of the belt. This double-sided toothed belt can be used for rotating the driven shaft in the opposite direction to the rotation of the drive shaft, or because the layout of the driven shaft is complicated and there is no room in space for hanging multiple belts. Used when you want to hang.

[0003] Japanese Patent Publication No. 6-43106 discloses a method for manufacturing such a double-sided toothed belt. The manufacturing method is specifically as follows.

[0004] First, a first elastic canvas is wound along the outer peripheral surface of a cylindrical mold in which strip-shaped projections and concave grooves are alternately formed in the outer surface axial direction, and a core wire is spirally wound thereon. Further, an unvulcanized rubber sheet having a predetermined thickness and a second elastic canvas are wound thereon, and the thus obtained belt molded body is heated and pressurized, and the unvulcanized rubber is pressed into the concave groove, By filling, a pre-formed body in a semi-vulcanized state is obtained. At this time, belt teeth are formed inside the preformed body.

[0005] Next, the preform is taken out from the cylindrical mold and wound around two toothed pulleys whose center distance can be adjusted.

Then, the upper and lower teeth are formed and vulcanized by sandwiching and pressing the preformed body wound around the toothed pulley by a pair of upper and lower press dies each having a toothed groove. At this time, the belt teeth inside the preform are supported by the tooth grooves provided in one press die. Then, belt teeth are formed on the outer peripheral surface of the preform by press working.

Subsequently, the position of the vulcanized portion where vulcanization has been completed is moved, and the above-mentioned molding vulcanization is sequentially repeated to obtain an endless vulcanized double-sided toothed belt.

[0008]

However, in the press working of the above manufacturing method, the temperature of the rubber rises while being pressed, so that the rubber is pressed without having sufficient fluidity. Becomes As a result, the unflowed rubber exerts pressure on the core wire, and the core wire buried in the bottom of the tooth formed on the outside of the belt shows a greatly crushed form as shown in FIG.

[0009] The crushing of the core wire causes a minute dimensional change in the core wire in the length direction, thereby affecting the belt length and impairing the meshing, thereby impairing the bending fatigue resistance of the double-sided toothed belt. Problem.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to reduce the poor meshing of a toothed belt and improve the bending fatigue resistance of the toothed belt. is there.

[0011]

SUMMARY OF THE INVENTION The present invention improves the fluidity of rubber by preheating the belt teeth on the outer peripheral surface of a double-sided toothed belt before press forming, thereby improving the fluidity of the rubber. Is prevented from being crushed by unflowable rubber. The ratio of the diameter of the core wire embedded in the toothed belt in the belt thickness direction to the diameter in the belt width direction is set to a predetermined range.

More specifically, the invention according to claim 1 is a method for manufacturing a double-sided toothed belt having belt teeth provided at a predetermined pitch on both the inside and outside of the belt, and the peripheral surface of the belt extends parallel to the cylindrical axis. A first canvas setting step of covering a cylindrical first canvas on a cylindrical mold having a plurality of tooth-shaped grooves, and a core wire forming a core layer by spirally winding the core wire on the first canvas. A setting step, a rubber setting step of covering an unvulcanized rubber on the core layer, and a second setting step on the rubber layer.
A second canvas setting step of covering the canvas, heating and pressing the first canvas provided on the cylindrical mold peripheral surface, the core wire, the unvulcanized rubber, and the second canvas. A preforming vulcanizing step of forming a cylindrical body having belt teeth on the inner peripheral surface, a releasing step of releasing the cylindrical body from the cylindrical mold, and a belt formed on the inner peripheral surface of the cylindrical body. A press preparation step of fitting the belt teeth of the cylindrical body into the tooth grooves of a plate-shaped first press die provided with tooth-shaped grooves having the same shape as the teeth on the surface of the die; The cylindrical body is sandwiched between a first press die and a plate-shaped second press die provided with a tooth-shaped groove having the same or different shape as the first press die on the die surface. A preliminary heating step of heating the cylindrical body without applying pressure, and a step of forming the first press die and the second press die Pressurizing and heating the cylinder by reducing the gap to form belt teeth on the outer peripheral surface of the cylinder and vulcanizing the rubber to a predetermined degree of vulcanization. I do.

In the above-described method for manufacturing a double-sided toothed belt, a preheating step is provided between the press preparation step and the press step. In this preheating step, the temperature of the rubber rises, the fluidity of the rubber increases, and the rubber flows smoothly so as to form belt teeth on the outer peripheral surface of the cylindrical body. Therefore, the core wire buried in the bottom of the tooth is not greatly crushed by the force from the rubber due to the poor fluidity of the rubber as in the prior art, and the dimensions of the core wire are stabilized. In addition, poor meshing of the double-sided toothed belt is reduced, and the bending fatigue resistance is improved.

In the pressing step, pressing is performed over the entire circumference of the belt. As a result, the cross section of the core wire embedded in the double-sided toothed belt to be manufactured has a substantially elliptical shape slightly compressed in the belt thickness direction. Therefore, while maintaining the strength as a core wire, the compressive stress on the inner circumferential side and the tensile stress on the outer circumferential side applied to the core wire when the belt is wound around the pulley are reduced, and the bending resistance of the double-sided toothed belt is reduced. Fatigue is improved.

According to a second aspect of the present invention, there is provided a toothed belt in which a cord is buried in a longitudinal direction of the belt, wherein a ratio of a diameter of the cord in a belt thickness direction to a diameter in a belt width direction is 0.1 mm. It is not less than 75 and not more than 1.00.

According to a third aspect of the present invention, the toothed belt according to the first aspect is a double-sided toothed belt having belt teeth both inside and outside the belt.

The invention according to claim 4 is characterized in that the toothed belt according to claim 1 is a single-sided toothed belt having belt teeth only inside the belt.

According to the configuration of each of the above-described toothed belts, the ratio of the diameter of the core wire embedded in the belt in the belt thickness direction to the diameter in the belt width direction is 0.75 or more. A small dimensional change in the direction is prevented, whereby poor meshing of the toothed belt is reduced, and the bending fatigue resistance of the belt is improved. Further, since the dispersion of the tension shared by the respective sections in the core wire section is reduced, the strength as the core wire is increased, and as a result, the belt strength is increased. On the other hand, since this ratio is set to 1.00 or less, the core diameter in the belt thickness direction does not become large, so that the compressive stress on the core inner peripheral side applied to the core when the belt is wound around the pulley and the outer circumference The tensile stress on the side does not become excessive, and the bending fatigue resistance of the belt is improved. In order to adapt to various sizes of pulleys, this ratio is preferably 0.95 or less, and more preferably 0.90 or less.

[0019]

As described above, according to the first aspect of the present invention, a preheating step is provided between the press preparation step and the press step. In this preheating step, the temperature of the rubber rises, the fluidity of the rubber increases, and the rubber flows smoothly so as to form belt teeth on the outer peripheral surface of the cylindrical body. Therefore, the core wire buried in the bottom of the tooth due to poor fluidity of the rubber is not greatly crushed by receiving pressure from the rubber, and the dimension in the length direction of the core wire is stabilized. Poor meshing of the attached belt is reduced, and the bending fatigue resistance is improved. Further, since the pressing process is performed over the entire circumference of the belt, the cross section of the cord embedded in the double-sided toothed belt to be manufactured has a substantially elliptical shape slightly compressed in the belt thickness direction. Therefore, while maintaining the strength as a core wire, the compressive stress on the inner circumferential side of the core wire and the tensile stress on the outer circumferential side applied to the core wire when the belt is wound around the pulley are reduced. Flex fatigue is improved.

According to the second to fourth aspects of the present invention, the ratio of the diameter of the cord in the belt thickness direction to the diameter in the belt width direction is within a predetermined range, so that the belt strength is greatly reduced. Without this, the poor meshing of the double-sided toothed belt is reduced, and the bending fatigue resistance is improved.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A toothed belt according to an embodiment of the present invention will be described in detail with reference to the drawings. (Embodiment 1) FIG. 1 shows a double-sided toothed belt A according to Embodiment 1 of the present invention. The double-sided toothed belt A is disposed at an equal pitch on the inner peripheral surface of the belt, and is disposed at an equal pitch on an inner tooth rubber portion 11 that forms inner belt teeth, and on an outer peripheral surface of the belt.
An outer tooth rubber portion 12 forming the outer belt teeth, an inner canvas 13 covering the belt surface on the inner tooth rubber portion 11 side, an outer canvas 14 covering the surface on the outer tooth rubber portion 12 side, and a belt longitudinal direction. And a buried core 15.

The inner tooth rubber portion 11 and the outer tooth rubber portion 12 use a rubber composition mainly composed of chloroprene rubber (CR) (hereinafter referred to as "CR composition"). Further, as the inner canvas 13 and the outer canvas 14, a nylon canvas having elasticity in a belt circumferential direction and subjected to an adhesive treatment with a rubber paste is used. And core wire 15
As resorcinol-formalin latex (hereinafter "R
FL ”. ) A glass core wire of a twisted yarn which has been subjected to a bonding treatment with a solution is used.

The tooth shape of the double-sided toothed belt A is a trapezoidal tooth, and the inner and outer belt teeth have the same tooth shape. Further, the inner belt teeth and the outer belt teeth are respectively provided at the same positions on the inner peripheral surface and the outer peripheral surface of the belt.

FIG. 2 is an enlarged cross-sectional view of the double-sided toothed belt A in a direction perpendicular to the longitudinal direction of the belt. The diameter (T) in the thickness direction of the core wire 15 in the core wire 15 appearing in the belt cross section
Is 0.82 with respect to the diameter (W) in the width direction.

Next, the operation and effect will be described.

The ratio of the diameter (T) of the core wire 15 embedded in the double-sided toothed belt A in the belt thickness direction to the diameter (W) in the belt width direction is set to 0.82. A small dimensional change of the belt tooth is prevented, so that the meshing failure of the belt teeth with the pulley groove is reduced, and the double-sided toothed belt A becomes excellent in bending fatigue resistance. In addition, since the variation in the tension shared by each part in the cross section of the core wire 15 is small, the strength of the core wire 15 is increased, and as a result, the strength of the double-sided toothed belt A is also increased. Further, since the ratio is 0.82, the core diameter (T) in the belt thickness direction does not become large, and the inner circumferential side of the core added to the core 15 when the belt is wound around the pulley. Double-sided toothed belt A because the stress and the tensile stress on the outer peripheral side do not become excessive.
Is excellent in bending fatigue resistance.

In the first embodiment, the CR composition is used as the rubber composition for forming the inner tooth rubber portion 11 and the outer tooth rubber portion 12. However, the present invention is not limited to this. ), Styrene butadiene rubber (SB
R), butyl rubber (IIR), butadiene rubber (B
R), a composition such as a nitrile rubber (NBR), a fluorine rubber, and a polyurethane elastomer can also be used.

In the first embodiment, the inner canvas 13
In addition, although the stretched nylon canvas is used as the outer canvas 14, the present invention is not particularly limited thereto, and a stretchable canvas made of polyester fiber, aromatic polyamide fiber, or the like may be used. The inner canvas and the outer canvas may be made of different types of fibers. In this case, different functions can be given to the inner belt surface and the outer belt surface of the double-sided toothed belt A.

In the first embodiment, a glass core wire is used as the core wire 15. However, the present invention is not particularly limited to this. A low elongation high strength aromatic polyamide fiber, polyester fiber, steel wire, etc. Can be used.

Further, in the first embodiment, the shapes of the inner belt teeth and the outer belt teeth of the double-sided toothed belt A are the same. However, the present invention is not particularly limited thereto. The shape of the teeth may be different. Since the shape of the inner belt teeth and the shape of the outer belt teeth are different, it is possible to drive the pulleys having different tooth shapes between the inside and outside of the belt, so that it is possible to have a degree of freedom in layout design. Similarly, the pitch of the inner belt teeth and the pitch of the outer belt teeth may be different. (Embodiment 2) A method for manufacturing the double-sided toothed belt A will be described. <First canvas setting step> As shown in FIG. 3, a cylindrical mold 31 having a large number of tooth-shaped grooves extending parallel to the cylindrical axis on the peripheral surface.
Then, a cylindrical first nylon canvas 32 which has elasticity in the circumferential direction of the mold and has been subjected to an adhesive treatment with rubber glue is put thereon. <Core Wire Setting Step> As shown in FIG. 4, a glass core wire 33 that has been subjected to an adhesive treatment with an RFL solution is wound on a first nylon canvas 32 in a double helical manner with a pair of S twists and Z twists. Form a layer of cords. <Rubber setting step> As shown in FIG.
The CR composition 34 in the form of a sheet is wound around the layer several times. <Second canvas setting step> As shown in FIG. 6, a second nylon canvas 35 which has elasticity in the circumferential direction of the mold and has been subjected to an adhesive treatment with a rubber paste is put on the CR composition 34. . At this time, the first nylon canvas 32, the glass core wire 33, the CR composition 34 and the second nylon
Nylon canvas 35 is sequentially formed in layers. <Preliminary Vulcanization Step> As shown in FIG. 7, the cylindrical mold 31 in which the above materials are set is put into a vulcanization can 36. Close the lid of the vulcanizing can 36, temperature 160 ° C, pressure 10kg / cm
Preliminary vulcanization is performed for 4 minutes under the conditions of ² (depending on the type of the CR composition, the temperature ranges from 160 ° C. to 180 ° C., the pressure ranges from 6 to 12 kg / cm ² , and the vulcanization time ranges from 1 to 14 minutes). And appropriate conditions are selected). At this time, CR composition 3
4 flows in the gap between the parallel glass core wires 33, and the periphery of the glass core wire 33 is covered with the CR composition 34. Further, the CR composition 34 presses the first nylon canvas 32 by an external pressure and is pressed into the tooth-shaped groove on the peripheral surface of the cylindrical mold, and starts the vulcanization reaction. Thus, on the outer peripheral surface of the cylindrical mold 31, a cylindrical body 37 having belt teeth whose inner peripheral surface is covered with the first nylon canvas is formed. <Releasing Step> As shown in FIG. 8, the cylindrical body 37 formed on the peripheral surface of the cylindrical
Release from 1. <Press preparation step> A cylindrical body is inserted into the tooth-shaped groove of a plate-shaped first press die 38 provided with a tooth-shaped groove having the same shape as the belt teeth formed on the inner peripheral surface of the cylindrical body 37 by preforming vulcanization. The belt teeth on the inner peripheral surface of 37 are fitted. <Preheating Step> As shown in FIG.
The second pressing die 39 having the same tooth profile grooves as the belt teeth on the outer peripheral surface of the cylindrical body
7 Press against the outer peripheral surface, set the temperature of both
Preheat for a minute. At this time, no pressure is applied to the cylindrical body 37. <Pressing Step> As shown in FIG.
9 was lowered to the first press mold 38 side, and pressed at a temperature of 170 ° C. and a pressure of 50 kg / cm ² for 8 minutes to form belt teeth on the outer peripheral surface of the cylindrical body 37 (type of CR composition) Depending on the temperature, 160 ° C to 180 ° C,
Appropriate conditions are selected at a pressure of 35 to 70 kg / cm ² and a vulcanization time of 6 to 9 minutes). Then, this press working is repeatedly performed on the entire outer peripheral surface of the cylindrical body 37. The second press die 38 is located at a position facing the tooth groove.
The press mold 39 is provided with a toothed groove, and the cylindrical body 37 is provided.
The belt teeth are formed at the same position on the inner and outer peripheral surfaces of the belt. <Width cutting step> The cylindrical body 37 provided with the belt teeth on both the inner peripheral surface and the outer peripheral surface is cut into a circle with a required width perpendicular to the axial direction. The production of the double-sided toothed belt A is performed as described above.

Next, the operation and effect will be described.

The method of manufacturing the double-sided toothed belt A is characterized in that a preheating step is provided between the press preparation step and the press step. In this preheating step, the temperature of the rubber is raised to increase the fluidity of the rubber, and the rubber flows smoothly so as to form belt teeth on the outer peripheral surface of the cylindrical body 37 as shown in FIG. Therefore, the glass core wire 33 buried in the bottom of the tooth does not receive a force from the rubber and is greatly crushed due to the poor fluidity of the rubber. Therefore, unlike the prior art, the core wire does not change minutely in the length direction, and the size of the glass core wire 15 is stabilized. It will be excellent.

Further, since the pressing process is performed over the entire circumference of the belt, the cross section of the glass core wire 33 embedded in the double-sided toothed belt A to be manufactured has a substantially elliptical shape slightly compressed in the belt thickness direction. Become. Accordingly, while maintaining the strength as the glass core wire 33 high, the compressive stress on the inner circumferential side and the tensile stress on the outer circumferential side applied to the glass core wire 33 when the belt is wound around the pulley are reduced, and the double-sided tooth is reduced. The attached belt A has excellent bending fatigue resistance. (Embodiment 3) FIG. 13 shows a single-sided toothed belt B according to Embodiment 3 of the present invention. The single-sided toothed belt B is arranged at equal pitches on the inner circumferential surface of the belt, and has a tooth rubber portion 51 forming belt teeth, a back rubber portion 52 outside the belt, and a tooth rubber portion 51.
A canvas 53 covering the surface of the belt on the side, and a cord 54 buried in the longitudinal direction of the belt.

A rubber compound mainly composed of chloroprene rubber (CR) is used for the tooth rubber portion 51 and the back rubber portion 52. Further, as the canvas 53, a nylon canvas having elasticity in the belt circumferential direction and having been subjected to an adhesive treatment with rubber glue is used. As the core wire 54, a glass core wire subjected to an adhesive treatment with an RFL solution is used.

As a feature of the present invention, the ratio of the diameter (T) in the thickness direction of the core wire 54 of the single-side toothed belt B to the diameter (W) in the width direction is 0.89.

Next, the operation and effect will be described.

The ratio of the diameter of the core wire embedded in the single-sided toothed belt B in the belt thickness direction to the diameter in the belt width direction is 0.8.
9, the minute dimensional change in the length direction of the core wire 54 is prevented, whereby the poor meshing of the belt teeth with the pulley grooves is reduced, and the single-sided toothed belt B has excellent bending fatigue resistance. It will be. In addition, since the variation in the tension shared by each part in the core wire section is small, the strength as the core wire is increased, and as a result, the strength of the single-side toothed belt B is also increased. Further, since the ratio is 0.89, the core diameter in the belt thickness direction does not become large, and the compressive stress on the core inner circumference side applied to the core when the belt is wound around the pulley and the outer circumferential side The tensile stress of the single-sided toothed belt B is also excellent from this point.

In the third embodiment, the tooth rubber portion 51
Although a CR composition was used as the rubber composition for forming the back rubber portion 52, the present invention is not particularly limited thereto, and natural rubber (NR), styrene butadiene rubber (SBR), butyl rubber (IIR), butadiene rubber ( A composition such as BR), nitrile rubber (NBR), fluororubber, and polyurethane elastomer can also be used.

In the third embodiment, a stretched nylon canvas is used as the canvas 53. However, the present invention is not limited to this, and the stretchable canvas made of polyester fiber, aromatic polyamide fiber, or the like is used. Can also be used.

In the third embodiment, a glass core wire is used as the core wire 54. However, the present invention is not particularly limited to this, and a low elongation high strength aromatic polyamide fiber, polyester fiber, steel wire, etc. Can be used.

[0041]

EXAMPLE A double-sided toothed belt C having the same configuration as the double-sided toothed belt A except that the preheating was not performed before the pressing step was used as a comparative example. A comparison of the ratio of the diameter (T) of the glass core wire appearing in the belt cross section in the belt thickness direction to the diameter (W) in the belt width direction and a bending fatigue test were performed. -Comparison of the ratio of the diameter (T) in the thickness direction of the core wire belt to the diameter (W) in the belt width direction-The belt width of both the double-sided toothed belt A according to the example and the double-sided toothed belt C according to the comparative example Cut the belt in the direction, take an enlarged photograph of the glass core wire cross section appearing in the cross section, measure the diameter (T) in the belt thickness direction and the diameter (W) in the belt width direction from the photograph, and measure the diameter in the belt thickness direction ( T) / diameter (W) in the belt width direction was calculated. Table 1 shows the results.

[0042]

[Table 1]

As shown in Table 1, the ratio of the diameter (T) of the cord in the belt thickness direction to the diameter (W) in the belt width direction of the core wire is larger than that of the double-sided toothed belt C of the comparative example. The toothed belt A is larger. That is, in the double-sided toothed belt A according to the embodiment, in the manufacturing process, since the preheating is performed before the pressing process, the pressing process is performed in a state where the rubber has a sufficient fluidity, so that the rubber is embedded in the tooth bottom. Thus, the shape of the core wire is maintained without being greatly crushed by the unflowed rubber. -Bending fatigue test-A bending fatigue test was performed on each of the belts of the above example and comparative example. Since the outer peripheral surface of the belt is wound on a pulley having a flat surface due to the layout of the running tester, the outer belt teeth of both the double-sided toothed belt A and the double-sided toothed belt C were scraped off and adjusted to a single-sided toothed belt. Then, as shown in FIG. 12, four large toothed pulleys 41 constituting the belt bending tester and four large pulleys 41 arranged between the adjacent large pulleys 41.
A single-sided toothed belt adjusted to a small pulley 42 (diameter 28 mm) with two flat surfaces is wrapped around, and a driving pulley is rotated in a state where a tension is applied to the single-sided toothed belt 44 with a weight 43 of 59 kg to rotate the driving pulley. 1.2 × toothed belt
10 ⁷ times was bent. Note that the number of rotations of the driving pulley is 55
70 rpm. The untested single-sided toothed belt and the single-sided toothed belt after running were each used as a strip-shaped test piece, and a tensile test was performed to calculate a residual belt strength.
Table 2 shows the results.

[0044]

[Table 2]

As is clear from Table 2, the double-sided toothed belt A according to the example is better than the double-sided toothed belt C according to the comparative example.
It can be seen that the residual strength ratio is higher than that of the above, and the flex fatigue resistance is excellent. That is, in the double-sided toothed belt A according to the embodiment,
In the manufacturing process, pre-heating is performed before the pressing process, so press molding is performed with rubber having sufficient fluidity, and the core embedded in the tooth bottom is greatly crushed by the non-flowable rubber Since the dimensions of the core wire are stable without any defects, the poor meshing of the double-sided toothed belt A is reduced, and the bending fatigue resistance is improved.
In addition, since the entire belt has been pressed, the cross section of the core wire has a substantially elliptical shape slightly compressed in the belt thickness direction as described above. The bending fatigue resistance is improved without excessive tensile stress on the side.

[Brief description of the drawings]

FIG. 1 is a perspective view of a double-sided toothed belt A according to the present invention.

FIG. 2 is an enlarged cross-sectional view in the belt width direction of the double-sided toothed belt A according to the present invention.

FIG. 3 is a diagram illustrating a first canvas setting step.

FIG. 4 is a diagram illustrating a core wire setting step.

FIG. 5 is a diagram illustrating a rubber setting step.

FIG. 6 is a diagram illustrating a second canvas setting step.

FIG. 7 is a view showing a state in which a cylindrical mold is placed in a vulcanization can for preforming vulcanization.

FIG. 8 is a diagram illustrating a demolding step.

FIG. 9 is a diagram illustrating a preheating step.

FIG. 10 is a diagram illustrating a pressing step.

FIG. 11 is a diagram showing a flow state of a rubber of a belt in a pressing step.

FIG. 12 is a diagram illustrating a layout of a belt bending fatigue tester.

FIG. 13 is a perspective view of a single-sided toothed B belt according to the present invention.

FIG. 14 is a side view of a double-sided toothed belt manufactured by a manufacturing method according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Inner tooth rubber part 12 Outer tooth rubber part 13 Inner canvas 14 Outer canvas 15 Cord 21 Rubber 31 Cylindrical mold 32 First nylon canvas 33 Glass core 34 CR composition 35 Second nylon canvas 36 Vulcanized can 37 Cylinder Body 38 First press mold 39 Second press mold 41 Large pulley 42 Small pulley 43 Weight 44 Single-sided toothed belt 51 Toothed rubber part 52 Back rubber part 53 Canvas 54 Core wire

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // B29K 21:00 105: 20 B29L 29:00

Claims (4)

[Claims] 1. A method of manufacturing a double-sided toothed belt having belt teeth provided at a predetermined pitch both inside and outside a belt, comprising: a cylindrical mold having a plurality of tooth-shaped grooves extending parallel to a cylindrical axis on a peripheral surface; A first canvas setting step of covering the first canvas with a cylindrical canvas, a core wire setting step of forming a core layer by spirally winding a core wire on the first canvas, A rubber setting step of covering an unvulcanized rubber, a second canvas setting step of covering a second canvas on the rubber layer, the first canvas provided on the peripheral surface of the cylindrical mold, and the core wire. A preforming vulcanizing step of heating and pressurizing the unvulcanized rubber and the second canvas to form a cylindrical body having belt teeth on the inner peripheral surface; and removing the cylindrical body from the cylindrical mold. A releasing step of releasing, a belt tooth formed on the peripheral surface of the cylindrical body A press preparation step of fitting the belt teeth of the cylindrical body into the tooth grooves of a plate-shaped first press die provided with a tooth groove of the same shape on the die surface; and the first press die and the first press die. The cylindrical body is sandwiched between a plate-shaped second press mold having a tooth-shaped groove facing the press mold and having the same or different shape as the first press mold provided on the mold surface; A preheating step of heating without applying pressure to the cylinder, heating and pressurizing the cylindrical body by reducing the distance between the first press mold and the second press mold, and belt teeth on the outer peripheral surface of the cylindrical body. And a pressing step of vulcanizing the rubber to a predetermined degree of vulcanization. 2. A toothed belt having a core buried in a belt longitudinal direction, wherein a ratio of a diameter of the core in a belt thickness direction to a diameter in a belt width direction is 0.75 or more and 1.00 or less. A toothed belt, characterized in that: 3. The double-sided toothed belt according to claim 1, wherein the toothed belt has belt teeth both inside and outside the belt. 4. The single-sided toothed belt according to claim 1, wherein the toothed belt has belt teeth only inside the belt.