JP2009041768A - Toothed belt and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toothed belt capable of preventing local generation of large stress in root portions of tooth parts during traveling of the belt and having high durability, and a manufacturing method for the toothed belt. <P>SOLUTION: The toothed belt 1 is provided with the plurality of tooth parts 2 arranged along the belt longitudinal direction at predetermined intervals; a back part 3 in which core wires 5 are embedded; a bonding layer 4 provided between the tooth parts 2 and the back part 2; and tooth cloth 5 covering the plurality of tooth parts 2. Portions of the bonding layer 4 contacted with the tooth parts 2 are swollen to the back part 3 side with respect to the core wires 5. This structure reduces stress generated in the bonding layer 4 during traveling of the belt 1, compared to the case where the bonding layer 4 is arranged in parallel with the core wires 5. Therefore, stress concentration generated in the root portions of the tooth parts 2 is alleviated. As a result, separation between the tooth parts 2 and the core wires 5 is suppressed and thereby, tooth cracks in the root portions of the tooth parts 2 are suppressed, so as to improve the durability of the toothed belt 1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a toothed belt and a manufacturing method thereof.

 Conventionally, as a toothed belt used in automobiles, general industrial machines, etc., a plurality of tooth portions arranged at predetermined intervals along the belt longitudinal direction, a back portion in which a core wire is embedded, and a tooth covering the tooth portion What is provided with cloth is known.

 As a method for manufacturing such a toothed belt, there is a preforming method for manufacturing a belt after previously forming a tooth portion and a tooth cloth (see, for example, Patent Document 1). Specifically, after setting an unvulcanized rubber sheet and a tooth cloth to be a tooth part on a grooved mold, a pre-molded body in which the tooth part is formed is manufactured by heating and pressing with a press. After this preformed body is installed in a cylindrical grooved mold, the core wire is spirally wound, and further, an unvulcanized rubber sheet as a back portion is wound thereon, and heated and pressurized to be a vulcanized belt sleeve. Manufacturing.

 Generally, in the toothed belt, it is preferable that the thickness of the rubber between the core wire and the tooth cloth between adjacent tooth portions is thin. Therefore, in the preforming method of Patent Document 1, most of the rubber constituting the unvulcanized rubber sheet is pushed into the tooth groove of the grooved mold to form the tooth portion, and the adjacent tooth portion is formed by the remaining rubber. The thinnest tooth bottom is formed between them.

 However, when trying to mold a thin tooth bottom as described above, the rubber that has become fluidized by heating enters the texture of the tooth cloth, and no rubber remains on the tooth cloth between adjacent tooth parts. There is a case. Therefore, a thin adhesive layer made of a rubber composition may be provided between the core wire and the tooth portion. Such an adhesive layer is provided in parallel with the core wire.

JP 2003-145635 A

  However, when a toothed belt having an adhesive layer as described above is run around a toothed pulley, a shearing force parallel to the core acts on the root part of the tooth part, so shear stress is applied to the adhesive layer. concentrate. Therefore, particularly when traveling under a high load condition, early separation between the adhesive layer and the core wire and early separation between the core wire and the tooth portion due to destruction of the adhesive layer itself are likely to occur.

  Accordingly, an object of the present invention is to provide a toothed belt having high durability and a method for manufacturing the same, which can prevent a large stress from being locally generated in the root portion of the tooth portion during belt running. To do.

Means for Solving the Problems and Effects of the Invention

  The toothed belt according to claim 1 is provided with a plurality of tooth portions arranged at predetermined intervals along the belt longitudinal direction, a back portion in which a core wire is embedded, and an adhesive provided between the tooth portion and the back portion. A layer and a tooth cloth covering the plurality of tooth portions, and a portion of the adhesive layer in contact with the tooth portions swells toward the back side or the tooth side with respect to the core wire. It is characterized by.

  When the toothed belt is run around a toothed pulley, a shearing force acts on the root portion of the tooth portion in the longitudinal direction of the belt. When the adhesive layer is provided in parallel with the core wire, the shearing force acts on the adhesive layer in a concentrated manner, so that a large shear stress is generated in the adhesive layer. On the other hand, in the present invention, the adhesive layer swells to the back side or the tooth part side at a portion in contact with the tooth part, and has an angle with respect to the core line. As a result, the shearing force is prevented from concentrating and acting on the adhesive layer, and the shear stress generated in the adhesive layer is reduced. Therefore, it is possible to prevent a large stress from being locally generated in the root portion of the tooth portion. That is, stress concentration generated at the root portion of the tooth portion can be relaxed. As a result, the separation between the tooth portion and the core wire is suppressed, thereby suppressing the occurrence of missing teeth at the root portion of the tooth portion, and the durability of the toothed belt is improved.

  The manufacturing method of the toothed belt according to claim 2 is provided between the tooth portion and the back portion, a plurality of tooth portions arranged at predetermined intervals along the belt longitudinal direction, a back portion in which a core wire is embedded, and A method of manufacturing a toothed belt comprising the adhesive layer formed and a tooth cloth covering the plurality of teeth, wherein the plurality of teeth are pre-formed on an unvulcanized rubber sheet. Manufacturing a preformed sheet including a portion, the adhesive layer, and the tooth cloth, a preforming step, installing the preformed sheet in a cylindrical belt sleeve manufacturing mold, a core wire, and the back portion A belt sleeve manufacturing step of winding a non-vulcanized rubber sheet constituting the belt and then vulcanizing to manufacture a belt sleeve, wherein the preforming step further includes a first mold and a second mold. Among the pair of press molds, the first mold in which a plurality of tooth spaces are formed A first laminating step of laminating the tooth cloth and an unvulcanized first rubber sheet having a thickness such that the volume of the tooth cloth is larger than the total volume of the plurality of tooth spaces; the tooth cloth and the first A rubber sheet is pressed between the pair of press dies under a predetermined pressure condition and a predetermined temperature condition to bring the first rubber sheet into a semi-vulcanized state, and the semi-vulcanized state. A first pressing step in which the rubber is pressed into the plurality of tooth spaces to form the plurality of teeth, and the second mold is temporarily removed, and the adhesive layer is formed on the plurality of formed teeth. A second laminating step of laminating an unvulcanized second rubber sheet, and the second rubber sheet laminated on the plurality of teeth, a predetermined pressure condition between the pair of press dies, and , Pressing under a predetermined temperature condition, and pressing the second rubber sheet to the plurality of tooth portions Characterized in that it comprises a second pressing step of forming the adhesion layer, the.

  According to said structure, since the volume of a 1st rubber sheet is larger than the total volume of a several tooth space, the volume of a tooth | gear part is larger than the volume of a tooth space. As a result, the adhesive layer made of the second rubber sheet laminated on the tooth portion has a shape that swells to the back side at the portion in contact with the tooth portion. Therefore, the shear stress generated in the adhesive layer during running of the belt is reduced as compared with the case where it is provided in parallel with the core wire. Therefore, the stress concentration generated at the root portion of the tooth portion is alleviated. As a result, peeling between the core wire and the tooth portion is suppressed, thereby preventing the occurrence of missing teeth at the root portion of the tooth portion and improving the durability of the toothed belt.

  According to a third aspect of the present invention, there is provided the toothed belt manufacturing method according to the second aspect, wherein after the first pressing step, when the second die is removed, the rubber constituting the tooth portion rises from the tooth gap. It is characterized by.

  According to the above configuration, in the second pressing step, after the second rubber sheet is press-bonded to a plurality of tooth portions by press bonding to form an adhesive layer, the adhesive layer is in contact with the tooth portions when the second mold is removed. , The shape swells to the opposite side of the tooth.

  A method for manufacturing a toothed belt according to a fourth aspect is the method according to the second or third aspect, wherein the volume of the first rubber sheet is 1.1 to 1.3 times the total volume of the plurality of tooth spaces. And

  According to said structure, while being able to reduce the shearing stress which arises in a contact bonding layer reliably, the vertical runout of a belt can be suppressed.

  According to a fifth aspect of the present invention, there is provided a toothed belt manufacturing method including a plurality of tooth portions arranged at predetermined intervals along a belt longitudinal direction, a back portion in which a core wire is embedded, and the tooth portion and the back portion. A method of manufacturing a toothed belt comprising the adhesive layer formed and a tooth cloth covering the plurality of teeth, wherein the plurality of teeth are pre-formed on an unvulcanized rubber sheet. Manufacturing a preformed sheet including a portion, the adhesive layer, and the tooth cloth, a preforming step, installing the preformed sheet in a cylindrical belt sleeve manufacturing mold, a core wire, and the back portion A belt sleeve manufacturing step of winding a non-vulcanized rubber sheet constituting the belt and then vulcanizing to manufacture a belt sleeve, wherein the preforming step further includes a first mold and a second mold. Among the pair of press molds, the first mold in which a plurality of tooth spaces are formed A first laminating step of laminating the tooth cloth and an unvulcanized first rubber sheet having a thickness such that the volume of the tooth cloth is smaller than the total volume of the plurality of tooth gaps; and the tooth cloth and the first A rubber sheet is pressed between the pair of press dies under a predetermined pressure condition and a predetermined temperature condition to bring the first rubber sheet into a semi-vulcanized state, and the semi-vulcanized state. A first pressing step for forming the plurality of tooth portions by flowing the rubber into the tooth gap, and once removing the second mold, and forming the adhesive layer on the plurality of formed tooth portions. A second laminating step of laminating a second rubber sheet for vulcanization, and the second rubber sheet laminated on the plurality of tooth portions between a pair of press dies, a predetermined pressure condition, and a predetermined And pressing the second rubber sheet to the plurality of teeth to form the adhesive layer. Characterized in that it comprises a second pressing step of the.

  According to said structure, since the volume of a 1st rubber sheet is smaller than the total volume of a several tooth space, the volume of a tooth | gear part is smaller than the volume of a tooth space. Thereby, the contact bonding layer which consists of a 2nd rubber sheet laminated | stacked on the several tooth part becomes a shape swelled in the tooth part side in the part which contact | connects a tooth part. Therefore, the shear stress generated in the adhesive layer when the belt runs is reduced as compared with the case where the shear stress is provided in parallel with the core wire. Therefore, the stress concentration generated at the root portion of the tooth portion is alleviated. As a result, peeling between the core wire and the tooth portion is suppressed, thereby preventing the occurrence of missing teeth at the root portion of the tooth portion and improving the durability of the toothed belt.

  The method for manufacturing a toothed belt according to claim 6 is the method according to claim 5, wherein, in the first pressing step, a gap exists between the formed tooth portion and the inner surface of the tooth gap. Features.

  According to the above configuration, when the preformed sheet is installed in the sleeve manufacturing mold in the belt sleeve manufacturing process, there is a gap between the inner surface of the tooth gap provided in the sleeve manufacturing mold and the tooth portion. . During vulcanization, the gap is filled with rubber that constitutes the tooth portion, so that the adhesive layer is formed in a shape that swells toward the tooth portion at the portion in contact with the tooth portion.

  The method for manufacturing a toothed belt according to claim 7 is the method according to claim 5 or 6, wherein the volume of the first rubber sheet is 0.7 to 0.9 times the total volume of the plurality of tooth spaces. And

  According to said structure, while being able to ensure the height of the tooth | gear part after vulcanization, the shear stress which arises in a contact bonding layer can be reduced reliably.

[First Embodiment]
The first embodiment of the present invention will be described below. As shown in FIG. 1, the toothed belt 1 of the present embodiment includes a plurality of tooth portions 2 arranged at predetermined intervals in the belt longitudinal direction, and a back portion 3 in which a core wire 5 is embedded along the belt longitudinal direction. The adhesive layer 4 is provided between the tooth portion 2 and the back portion 3 and the tooth cloth 6 that covers the plurality of tooth portions 2. The back portion 3 may be covered with a canvas.

  In the adhesive layer 4, the portion in contact with the tooth portion 2 swells toward the back portion 3 with respect to the core wire 5. The adhesive layer 4 is interposed between the core wire 5 and the tooth cloth 6 between the two adjacent tooth portions 2.

  The tooth part 2 and the back part 3 are composed of a rubber composition. As the rubber component, for example, hydrogenated nitrile rubber (HNBR), nitrile rubber (NBR), hydrogenated nitrile rubber and unsaturated carboxylic acid metal salt are added. Additions, chlorosulfonated polyethylene rubber (CSM), alkylated chlorosulfonated polyethylene rubber (CSM), ethylene / α-olefin copolymer rubber such as ethylene / propylene rubber (EPM), chloroprene rubber, natural rubber, etc. These may be used alone or in combination.

  The rubber composition may be mixed with one or more short fibers selected from polyamides such as nylon 6 and nylon 66, polyester, cotton, and aramid. Thereby, the tooth part 2 and the back part 3 are hard to crack, and even if cracked, it is difficult to propagate.

  Furthermore, the rubber composition is filled with vulcanizing agents such as sulfur and organic peroxides, vulcanizing aids such as maleimide, vulcanization accelerators, reinforcing agents such as carbon black and silica, calcium carbonate and talc. Agents, softeners, processing aids, anti-aging agents and the like are blended.

  The adhesive layer 4 is made of a rubber composition. As the rubber component, for example, hydrogenated nitrile rubber (HNBR) is used. The rubber composition also includes vulcanizing agents such as organic peroxides, vulcanizing aids such as maleimide, vulcanization accelerators, reinforcing agents such as carbon black and silica, fillers, softeners, and processing aids. Antiaging agent etc. are blended.

  As the core 5, a low-stretch and high-strength twisted cord such as nylon fiber, aramid fiber, polyester fiber, glass fiber, or carbon fiber is used. These twisted cords are subjected to an adhesion treatment for the purpose of improving the adhesion to rubber.

  As an adhesion treatment, an untreated twisted cord is immersed in a treatment liquid composed of an epoxy compound or an isocyanate compound and pre-dipped, followed by heating and drying, followed by immersion in an RFL (resorcin-formalin-latex) liquid, followed by heating. The film may be stretched while performing both the adhesion treatment and the stretching treatment. The RFL liquid is a mixture of an initial condensate of resorcin and formalin mixed with latex. Latex such as chloroprene rubber, styrene / butadiene / vinylpyridine terpolymer, hydrogenated nitrile rubber, nitrile rubber, etc. Can be used.

  The tooth cloth 6 is composed of a fiber fabric woven with wefts extending in the belt longitudinal direction and warps extending in the width direction. Examples of the material of the fiber fabric include nylon fiber, aramid fiber, polyester fiber, polybenzoxazole fiber, cotton, and the like, which are used alone or in combination. Further, the form of the fibers constituting the weft and the warp may be either a filament yarn or a spun yarn. Moreover, as a textile structure of the said fiber fabric, any of a plain fabric, a twill fabric, a satin fabric, etc. may be sufficient. In this case, it is preferable to use a part of a weft nylon yarn having elasticity, urethane elastic yarn, or a mixed twist of urethane elastic yarn and nylon yarn as the weft.

  Furthermore, as the fiber woven fabric, a multi-woven (double woven) structure in which at least two types of wefts and one type of warp are woven can be employed. In this case, it is preferable to use nylon fiber for the warp and to use fluorine-based fiber, nylon fiber, polyester fiber or urethane elastic yarn for the weft. Of the wefts, as the wefts on at least the surface side of the tooth cloth 6 (the side meshing with the toothed pulley), it is preferable to use, for example, a fluorine-based fiber having a low friction coefficient such as PTFE fiber. Thereby, the friction between the tooth cloth 6 and the toothed pulley can be reduced. On the other hand, it is preferable to use a fiber other than a fluorine-based fiber such as nylon fiber or urethane elastic thread for the weft thread on the side of the tooth cloth 6 that contacts the tooth portion 2, and thereby the adhesive force between the tooth cloth 6 and rubber. Can be increased.

  Further, the fiber fabric can be used after being dipped in an RFL solution and then heat-dried. Thereby, the adhesive force of the tooth cloth 6 and rubber becomes high. Further, after the RFL treatment, a friction treatment in which an unvulcanized rubber is rubbed or a spreading treatment in which a rubber paste in which a rubber composition is dissolved in a solvent is applied may be used. As the latex, latex such as styrene / butadiene / vinylpyridine terpolymer, chlorosulfonated polyethylene, hydrogenated nitrile rubber, chloroprene rubber and the like can be used.

  As described above, the toothed belt 1 having the above configuration is interposed between the core wire 5 and the tooth cloth 6 between the two tooth portions 2 adjacent to each other. Therefore, the adhesiveness between the core wire 5 and the tooth cloth 6 is improved.

  When the toothed belt 1 is run around a toothed pulley (not shown), a shearing force acts on the root portion of the tooth portion 2 in the belt longitudinal direction. Therefore, when the adhesive layer is provided in parallel with the core wire, the shear stress concentrates on the adhesive layer, and thus a large shear stress is generated on the adhesive layer. On the other hand, as described above, in the adhesive layer 4 of the present embodiment, the portion in contact with the tooth portion 2 swells toward the back portion 3 with respect to the core wire 5 and has an angle with respect to the core wire 5. As a result, the shearing force is prevented from concentrating and acting on the adhesive layer 4, and the shear stress generated in the adhesive layer 4 is reduced. Therefore, it is possible to prevent a large stress from being locally generated in the root portion of the tooth portion 2. That is, the stress concentration generated at the root portion of the tooth portion 2 can be relaxed. As a result, the separation between the tooth portion 2 and the core wire 5 is suppressed, whereby the occurrence of missing teeth at the root portion of the tooth portion 2 is suppressed, and the durability of the toothed belt 1 is improved.

  Next, the manufacturing method of said toothed belt 1 is demonstrated. As a manufacturing process of the toothed belt 1, first, a preforming process for manufacturing a preformed sheet in which teeth are formed is performed, and then a belt sleeve manufacturing process for manufacturing a belt sleeve using the preformed sheet. I do. First, the preforming process will be described.

(First lamination step)
A pair of press dies 20 including a flat plate-like first die 21 having a plurality of tooth grooves 23 and a flat plate-like second die 22 are prepared. The tooth groove 23 of the first mold 21 is formed in a concave shape corresponding to the convex shape of the tooth portion 2 of the toothed belt 1. As shown in FIG. 2A, the tooth cloth 6 and the unvulcanized first rubber sheet 10 for forming the tooth part 2 are sequentially laminated on the first mold 21 arranged on the lower side. As the 1st rubber sheet 10, what has the thickness from which the volume becomes larger than the total volume of a plurality of tooth gaps 23 is used. In particular, those having a thickness such that the volume is 1.1 to 1.3 times the total volume of the plurality of tooth spaces 23 are preferably used.

  Next, the surface of the laminated first rubber sheet 10 is covered with a release film 24. As the release film 24, for example, a film having excellent heat resistance and excellent peelability for rubber and metal, such as polymethylpentene and polyethylene terephthalate, is used.

(First press process)
After installing the second mold 22 on the release film 24, the tooth cloth 6, the first rubber sheet 10, and the release film 24 are placed between a pair of press dies 20 with a predetermined pressure condition and a predetermined The first rubber sheet 10 is brought into a semi-vulcanized state by pressing under the temperature conditions of As the heating and pressurizing conditions of this press, for example, the temperature is 80 to 140 ° C., the pressing force is 1 to 5 MPa, and the pressing is performed for about 1 to 5 minutes.

  As shown in FIG. 2B, during the pressing, the first rubber sheet 10 becomes fluidized by heating and pressing, and flows into the plurality of tooth grooves 23 of the first mold 21 while spreading the tooth cloth 6. . Even after the inside of the tooth groove 23 is filled with rubber (and the tooth cloth 6), the pressure is further applied, and almost all of the semi-vulcanized rubber is pushed into the tooth groove 23. Thereby, a plurality of tooth portions 2 corresponding to the plurality of tooth grooves 23 of the first mold 21 are formed. Further, almost all of the rubber constituting the first rubber sheet 10 is pushed into the plurality of tooth spaces 23, and the surface of the tooth cloth 6 is almost exposed between the two adjacent tooth portions 2.

(Second lamination step)
Next, the second mold 22 is once removed. At this time, since the volume of the first rubber sheet 10 is larger than the total volume of the plurality of tooth spaces 23, the volume of the tooth portion 2 pushed into one tooth space 23 is larger than the volume of the tooth spaces 23. Therefore, the rubber constituting the tooth portion 2 rises from the tooth groove 23 of the first mold 21 due to the repulsive elastic force of the rubber.

  Next, the release film 24 is peeled from the surface of the tooth portion 2. Thereafter, as shown in FIG. 2 (c), an unvulcanized second rubber sheet 11 for forming the adhesive layer 4 and a release film 25 are laminated on the plurality of tooth portions 2 and the exposed tooth cloth 6. . The release film 25 is the same as the release film 24.

(Second press process)
Next, the second mold 22 is placed again on the release film 25. Then, the second rubber sheet 11 and the release film 25 are pressed together with the tooth portion 2 and the tooth cloth 6 between a pair of press dies 20 under a predetermined pressure condition and a predetermined temperature condition. As shown in FIG. 2 (d), the second rubber sheet 11 becomes the adhesive layer 4 by being pressure-bonded to the plurality of tooth portions 2 by this heating and pressing. That is, the adhesive layer 4 is formed in this step. The heating and pressing conditions at this time are set lower than the conditions of the first pressing step, the temperature is 80 to 140 ° C., the pressing force is 1 MPa or less, and the pressing time is within one minute.

  The preformed sheet 12 composed of the plurality of tooth portions 2, the adhesive layer 4, and the tooth cloth 6 is manufactured through the above steps, and then the mold is removed from the pair of press dies 20. As described above, since the molded tooth portion 2 has a raised shape when the second mold 22 is removed, the adhesive layer 4 made of the second rubber sheet 11 that is pressure-bonded to the tooth portion 2 is attached to the tooth portion 2. The shape swells along. That is, the adhesive layer 4 is formed in a shape that swells on the opposite side of the tooth portion 2 at the portion in contact with the tooth portion 2.

  And when the number of the tooth | gear parts 2 of the preforming sheet 12 is the same as or more than the number of the tooth | gear parts 2 of the toothed belt 1, it transfers to a belt sleeve manufacturing process. On the other hand, when the number is smaller than the number of the tooth portions 2 of the toothed belt 1, a plurality of preformed sheets 12 are manufactured according to the number of the tooth portions 2, and then the process proceeds to the belt sleeve manufacturing process.

  Next, the belt sleeve manufacturing process will be described. First, a cylindrical mold (belt sleeve manufacturing mold) 26 in which a plurality of tooth grooves 27 are formed along the circumferential direction on the outer peripheral surface is prepared. The volume and shape of the tooth groove 27 of the mold 26 are the same as the tooth groove 23 of the first mold 21. As shown in FIG. 3A, the preformed sheet 12 is placed on the outer peripheral surface of the mold 26 while the tooth portion 2 of the preformed sheet 12 is fitted in the tooth groove 27 of the mold 26. On the outer periphery of the preformed sheet 12, the core wire 5 is wound spirally. At this time, the core wire 5 bites into the swelled portion of the adhesive layer 4 and is further wound so as to be in contact with the non-swelled portion of the adhesive layer 4. FIGS. 3A and 3B are cross-sectional views passing through the gap between the core wires 5 wound spirally. Next, the unvulcanized third rubber sheet 13 constituting the back portion 3 is wound from above the core wire 5, and the jacket 28 is covered on the outer peripheral surface and heated and pressurized, and the tooth portion 2, the adhesive layer 4, The unvulcanized third rubber sheet 13 is vulcanized. The heating and pressing conditions at this time are, for example, a temperature of 130 to 180 ° C. and a pressing force of 0.20 to 0.85 MPa for about 40 to 60 minutes.

  As shown in FIG. 3 (b), the third rubber sheet 13 is fluidized by the heat and pressure during the heat and pressure and flows into the gap between the core wires 5. Thereby, the back part 3 which embeds the core wire 5 is formed.

  Here, the tooth portion 2 of the preformed sheet 12 has already been vulcanized to some extent. Therefore, when the tooth part 2 and the core wire 5 are in direct contact with each other, the adhesiveness is lowered. Therefore, the adhesiveness between the tooth portion 2 and the core wire 5 is improved by interposing the adhesive layer 4 that is hardly vulcanized between the tooth portion 2 and the core wire 5.

  Through the above process, the belt sleeve 14 including the tooth cloth 6, the plurality of tooth portions 2, the adhesive layer 4, the core wire 5, and the back portion 3 is manufactured. After removing the belt sleeve 14, the belt sleeve 14 is suspended on two rotating rolls, and is cut into a predetermined width by a cutter while being rotated by applying a predetermined tension, thereby completing individual toothed belts 1 shown in FIG. .

  When the volume of the first rubber sheet 10 is smaller than 1.1 times the total volume of the plurality of tooth spaces 23, the swelling of the adhesive layer 4 toward the back portion 3 side becomes small, and thus occurs in the adhesive layer 4 during belt running. In some cases, the shear stress is hardly reduced as compared with the case where the shear stress is provided in parallel with the core wire 5. On the other hand, when the volume of the first rubber sheet 10 is larger than 1.3 times the total volume of the plurality of tooth grooves 23, almost all of the semi-vulcanized rubber is put into the tooth grooves 23 in the first pressing step. You may not be able to push in. In such a case, when the toothed belt 1 is manufactured by using a plurality of the preformed sheets 12, the belt thickness is not constant in the belt longitudinal direction, and therefore the vertical runout of the belt increases during belt running. Therefore, by setting the volume of the first rubber sheet 10 to 1.1 to 1.3 times the total volume of the plurality of tooth spaces 23, the shear stress generated in the adhesive layer 4 can be reliably reduced, and the belt Can suppress vertical runout.

  In this embodiment, a flat mold is used as the second mold 22, but a mold having a recess formed at a position facing the tooth groove 23 of the first mold 21 is used. Also good.

[Second Embodiment]
Next, a second embodiment of the present invention will be described focusing on differences from the first embodiment. However, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted as appropriate.

  As shown in FIG. 4, the toothed belt 1 </ b> A of the present embodiment is replaced by the tooth portion 2 </ b> A, the back portion 3, and the adhesive layer 4 of the first embodiment. An adhesive layer 4A is provided.

  In the adhesive layer 4 </ b> A, the portion in contact with the tooth portion 2 </ b> A swells toward the tooth portion 2 </ b> A with respect to the core wire 5. As a result, the shear stress generated in the adhesive layer 4 </ b> A during running of the belt is reduced as compared with a case where the shear stress is provided in parallel with the core wire 5. Therefore, stress concentration occurring at the root portion of the tooth portion 2A can be reduced. As a result, the separation between the tooth portion 2A and the core wire 5 is suppressed, whereby the occurrence of missing teeth at the root portion of the tooth portion 2A is suppressed, and the durability of the toothed belt 1A is improved.

  Next, a method for manufacturing the toothed belt 1A will be described. The press mold 20 and the mold (belt sleeve manufacturing mold) 26 are the same as those in the first embodiment. Furthermore, the heating and pressing conditions in the first pressing step, the second pressing step, and the vulcanization step in manufacturing the belt sleeve are the same as those in the first embodiment.

  As the first rubber sheet 10 </ b> A for forming the tooth portion 2, a sheet having a thickness such that the volume is smaller than the total volume of the plurality of tooth grooves 23 of the first mold 21 is used. In particular, those having a thickness such that the volume is 0.7 to 0.9 times the total volume of the tooth spaces 23 are preferably used.

  As shown to Fig.5 (a), after performing a 1st lamination process similarly to 1st Embodiment, it transfers to a 1st press process. As shown in FIG. 5B, at the time of this pressing, the first rubber sheet 10A becomes fluidized by heating and pressing, and almost all of the tooth grooves 23 of the first mold 21 are spread while spreading the tooth cloth 6. A plurality of tooth portions 2A are formed. At this time, since the volume of the first rubber sheet 10 </ b> A is smaller than the total volume of the plurality of tooth spaces 23, the volume of the tooth portion 2 </ b> A flowing into one tooth space 2 is smaller than the volume of the tooth spaces 23. Therefore, there is a gap between the tooth portion 2 </ b> A and the inner surface of the tooth groove 23.

  Next, as shown in FIG.5 (c), after performing a 2nd lamination process, as shown in FIG.5 (d), a 2nd press process is performed. As a result, an adhesive layer 4A made of the second rubber sheet 11 pressure-bonded to the tooth portion 2A is formed.

  The preformed sheet 12A composed of the plurality of tooth portions 2A, the adhesive layer 4A, and the tooth cloth 6 is manufactured through the above steps.

Next, the belt sleeve manufacturing process will be described.
As shown in FIG. 6A, the preformed sheet 12 </ b> A is placed on the outer peripheral surface of the mold 26 while the tooth portion 2 </ b> A of the preformed sheet 12 </ b> A is fitted into the tooth groove 27 of the mold 26. At this time, since the volume and shape of the tooth groove 27 of the mold 26 are the same as the tooth groove 23 of the first mold 21, there is a gap between the tooth portion 2 </ b> A and the inner surface of the tooth groove 27. Next, the core wire 5 is spirally wound on the outer periphery of the preformed sheet 12A, the unvulcanized third rubber sheet 13A is wound on the core sheet 5A, and then vulcanized to obtain the vulcanization shown in FIG. 6 (b). A sulfur belt sleeve 14A is manufactured.

  As shown in FIG. 6 (b), at the time of this heating and pressing, the tooth portion 2A and the adhesive layer 4A of the preformed sheet 12A become fluidized by heating and pressing, and the tooth cloth 27 inside the tooth groove 27 is pushed and spread. It flows into the gap. Then, by filling the gap with rubber, the height of the tooth portion 2A becomes substantially the same as the depth of the tooth gap 27. Further, the adhesive layer 4A is formed in a shape in which a portion in contact with the tooth portion 2A enters the tooth gap 27 and swells toward the tooth portion 2A. At the same time, the third rubber sheet 13 </ b> A also becomes fluidized by heating and pressing, and a part of the third rubber sheet 13 </ b> A passes through the gap of the core wire 5 and flows into the tooth gap 27. Thereby, the back portion 3A is formed.

  When the volume of the first rubber sheet 10A is larger than 0.9 times the total volume of the plurality of tooth spaces, the swelling of the adhesive layer 4A toward the tooth portion 2A is reduced, and thus shearing that occurs in the adhesive layer 4A during belt running The stress may be hardly reduced as compared with the case where the stress is provided in parallel with the core wire 5. On the other hand, when the volume of the first rubber sheet 10A is smaller than 0.7 times the total volume of the plurality of tooth grooves 23, the gap between the inner surface of the tooth groove 27 of the mold 26 and the tooth portion 2 also increases. During the vulcanization, the gap cannot be completely filled with rubber, and the height of the tooth portion 2A of the belt sleeve 14A may be smaller than the depth of the tooth groove 27. Therefore, by setting the volume of the first rubber sheet 10A to 0.7 to 0.9 times the total volume of the plurality of tooth spaces, the height of the tooth portion 2A after vulcanization can be secured and bonded. The shear stress generated in the layer 4A can be reliably reduced.

  In this embodiment, in the first pressing step, there is a gap between the tooth portion 2A and the inner surface of the tooth groove 23. However, the volume of the tooth portion 2A is the volume of the plurality of tooth grooves 23. If it is smaller than this, this gap may not be present. For example, by pouring the rubber constituting the tooth portion 2 </ b> A to the bottom of the tooth groove 23, there is no gap between the tooth portion 2 </ b> A and the inner surface of the tooth groove 23, and between the tooth portion 2 </ b> A and the second mold 22. You may make it leave a clearance gap. Alternatively, as the second mold 22, a convex part is formed at a position facing the tooth groove 23 of the first mold 21, and between the tooth part 2 </ b> A and the pair of press dies 20. There may be no gap.

  The effects of the present invention will be verified below with specific examples.

  As the first rubber sheet and the third rubber sheet constituting the tooth part and the back part, unvulcanized rubber compositions having the composition shown in Table 1 were prepared.

  Moreover, the unvulcanized rubber sheet which consists of a rubber composition of the mixing | blending shown in Table 2 as a 2nd rubber sheet which comprises an contact bonding layer was prepared.

  As a tooth cloth, a double woven canvas using polyester fibers and PTFE fibers as wefts and nylon fibers as warps was prepared. And after immersing this double woven canvas in RFL liquid, it heat-dried and the adhesion | attachment process was performed.

  Moreover, the aramid fiber twisted cord was prepared as a core wire. And after immersing this unprocessed code | cord | chord in RFL liquid, what heated and dried and performed the adhesion process was prepared.

Next, the manufacturing method of a toothed belt is shown.
In Example 1, as the first rubber sheet, the first rubber sheet having a thickness that is 1.2 times the total volume of the plurality of tooth gaps of the first mold is described in the first embodiment. According to the method, a toothed belt swelled on the back side at a portion where the adhesive layer is in contact with the tooth portion was produced. The produced toothed belt had a tooth type: Y, a tooth pitch: 8 mm, a number of teeth: 105, and a belt width: 15 mm. In addition, the heating and pressing conditions in the first pressing step for forming the tooth portion are a temperature of 130 to 140 ° C., a pressing force of 2.5 to 3.5 MPa, and a time of 2 to 3 minutes. The pressure conditions are a temperature of 130 to 140 ° C., a pressing force of 0.5 to 1.0 MPa, and a pressure of 15 to 30 seconds. The heating and pressurizing conditions for producing the vulcanized belt sleeve are a temperature of 130 to 180 ° C. and a pressing force. It was 0.25 to 0.85 MPa, 40 to 60 minutes.

  In Example 2, as the first rubber sheet, a material having a thickness such that the volume of the first rubber sheet is 0.7 times the total volume of the plurality of tooth spaces of the first mold is used. By the method described above, a toothed belt swelled toward the tooth portion at the portion where the adhesive layer is in contact with the tooth portion was produced.

  In Comparative Example 1, a first rubber sheet having a thickness that is approximately the same as the total volume of the plurality of tooth spaces of the first mold is used. As in the first embodiment, in the first pressing step, while the second rubber sheet is in a semi-vulcanized state, almost all of the second rubber sheet is poured into the tooth gap of the first mold to form the tooth portion, and the tooth portion and the tooth cloth are formed. A preformed sheet was prepared. Then, the preformed sheet was wound around a belt sleeve manufacturing mold, and the core wire and the third rubber sheet were wound and vulcanized, and then cut into a predetermined width to produce a toothed belt without an adhesive layer.

  In Comparative Example 2, the first rubber sheet having the same thickness as Comparative Example 1 was used. After forming the tooth portion in the first pressing step, the second rubber sheet is pressure-bonded to the tooth portion in the second pressing step in the same manner as in the embodiment to form the adhesive layer, and the preliminary consisting of the adhesive layer, the tooth portion, and the tooth cloth A molded sheet was produced. And the toothed belt by which the contact bonding layer was provided in parallel with the core wire was produced using this preforming sheet.

  A high load running test was performed on the toothed belts of the above examples and comparative examples. A toothed belt was suspended on a test device consisting of a 19-tooth drive pulley and a 38-tooth driven pulley, and a running test was performed under high load conditions of a drive pulley rotational speed of 7200 rpm, a driven pulley load of 7.5 Nm, and an initial tension of 350 N. Table 3 shows the durability life and failure modes. The “peeling” shown in Table 3 means peeling at the interface between the core wire and the rubber adhering to the tooth portion side of the core wire. Further, “tooth side” shown in Table 3 means that the portion of the adhesive layer that contacts the tooth portion swells toward the tooth portion with respect to the core wire. Further, “back side” means that the portion of the adhesive layer that contacts the tooth portion swells toward the back side with respect to the core wire. “Parallel” means that the adhesive layer is parallel to the core wire.

  As a result of the test, it was found that the example had a longer durability life than the comparative example, and the peeling between the core wire and the tooth portion was suppressed. In addition, the durability life of Example 1 was longer than that of Example 2. Thereby, when the adhesive layer swelled to the back part side, it turned out that peeling between a core wire and a tooth part is suppressed more compared with the case where it swells to the tooth part side.

It is a perspective view of a toothed belt concerning a 1st embodiment of the present invention. It is a figure which shows the preforming process in the manufacturing process of a toothed belt. It is a figure which shows the belt sleeve manufacturing process in the manufacturing process of a toothed belt. It is a perspective view of the toothed belt which concerns on 2nd Embodiment of this invention. It is a figure which shows the preforming process in the manufacturing process of a toothed belt. It is a figure which shows the belt sleeve manufacturing process in the manufacturing process of a toothed belt.

Explanation of symbols

1, 1A Toothed belt 2, 2A Tooth part 3, 3A Back part 4, 4A Adhesive layer 5 Core 6 Tooth cloth 10, 10A First rubber sheet 11 Second rubber sheet 12, 12A Pre-formed sheet 13, 13A Third rubber Sheets 14, 14A Belt sleeve 20 Press mold 21 First mold 22 Second mold 23 Tooth groove 26 Mold (mold for belt sleeve production)
27 tooth gap

Claims (7)

A plurality of teeth arranged at predetermined intervals along the longitudinal direction of the belt;
A back with an embedded core;
An adhesive layer provided between the tooth portion and the back portion;
A tooth cloth covering the plurality of tooth portions;
With
The toothed belt, wherein a portion of the adhesive layer in contact with the tooth portion swells toward the back side or the tooth portion side with respect to the core wire. A plurality of tooth portions arranged at predetermined intervals along the belt longitudinal direction, a back portion in which a core wire is embedded, an adhesive layer provided between the tooth portion and the back portion, and the plurality of tooth portions A method of manufacturing a toothed belt provided with a covering tooth cloth,
Preforming the plurality of teeth on an unvulcanized rubber sheet to produce a preformed sheet including the plurality of teeth, the adhesive layer, and the tooth cloth;
After the preformed sheet is installed in a cylindrical belt sleeve manufacturing mold, the core wire and the unvulcanized rubber sheet constituting the back portion are wound, and then vulcanized to produce a belt sleeve. A belt sleeve manufacturing process,
The preforming step further includes:
Of the pair of press dies composed of the first die and the second die, the first die having a plurality of tooth grooves formed on the tooth cloth and the total volume of the plurality of tooth grooves. A first lamination step of laminating an unvulcanized first rubber sheet having a thickness larger than the volume;
The tooth cloth and the first rubber sheet are pressed between the pair of press dies under a predetermined pressure condition and a predetermined temperature condition to bring the first rubber sheet into a semi-vulcanized state. A first pressing step of pressing the semi-vulcanized rubber into the plurality of tooth spaces to form the plurality of tooth portions;
A second lamination step of once removing the second mold and laminating the unvulcanized second rubber sheet constituting the adhesive layer on the plurality of formed tooth portions;
The second rubber sheet laminated on the plurality of tooth portions is pressed between the pair of press dies under a predetermined pressure condition and a predetermined temperature condition, and the second rubber sheet is A second pressing step in which the adhesive layer is formed by pressure bonding to a plurality of tooth portions;
The manufacturing method of a toothed belt characterized by including.   3. The toothed belt according to claim 2, wherein when the second mold is removed after the first pressing step, the rubber constituting the tooth portion rises from the tooth gap. 4. Production method.   The method for manufacturing a toothed belt according to claim 2 or 3, wherein a volume of the first rubber sheet is 1.1 to 1.3 times a total volume of the plurality of tooth gaps. A plurality of tooth portions arranged at predetermined intervals along the belt longitudinal direction, a back portion in which a core wire is embedded, an adhesive layer provided between the tooth portion and the back portion, and the plurality of tooth portions A method of manufacturing a toothed belt provided with a covering tooth cloth,
Preforming the plurality of teeth on an unvulcanized rubber sheet to produce a preformed sheet including the plurality of teeth, the adhesive layer, and the tooth cloth;
After the preformed sheet is installed in a cylindrical belt sleeve manufacturing mold, the core wire and the unvulcanized rubber sheet constituting the back portion are wound, and then vulcanized to produce a belt sleeve. A belt sleeve manufacturing process,
The preforming step further includes:
Of the pair of press dies composed of the first die and the second die, the first die having a plurality of tooth grooves formed on the tooth cloth and the total volume of the plurality of tooth grooves. A first laminating step of laminating an unvulcanized first rubber sheet having a thickness that is smaller than the volume;
The tooth cloth and the first rubber sheet are pressed between the pair of press dies under a predetermined pressure condition and a predetermined temperature condition to bring the first rubber sheet into a semi-vulcanized state. A first pressing step of forming the plurality of tooth portions by allowing the semi-vulcanized rubber to flow into the tooth gap;
A second laminating step of temporarily removing the second mold and laminating an unvulcanized second rubber sheet constituting the adhesive layer on the plurality of formed tooth portions;
The second rubber sheet laminated on the plurality of tooth portions is pressed between the pair of press dies under a predetermined pressure condition and a predetermined temperature condition, and the second rubber sheet is A second pressing step in which the adhesive layer is formed by pressure bonding to a plurality of tooth portions;
The manufacturing method of a toothed belt characterized by including.   6. The method for manufacturing a toothed belt according to claim 5, wherein a gap exists between the molded tooth portion and the inner surface of the tooth gap in the first pressing step. The method for manufacturing a toothed belt according to claim 5 or 6, wherein the volume of the first rubber sheet is 0.7 to 0.9 times the total volume of the plurality of tooth gaps.

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