JP2007231978A - Toothed belt and tooth portion reinforcing material to be used for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toothed belt wherein tooth rubber portions have surfaces covered with fiber fabrics and a short fiber bound layer formed by melting and solidifying an olefin short fiber group is arranged on the surfaces of the tooth rubber portions, having reduced friction resistance for a long period to contribute to improving the life of the belt, and to provide a tooth portion reinforcing material to be used for the same. <P>SOLUTION: The toothed belt 1 comprises a back rubber portion 4 in which core wires 3 are embedded, and a plurality of tooth rubber portions 2 arranged on the back rubber portion 4 at predetermined pitches in the longitudinal direction of the belt. A tooth portion reinforcing member 5 is adhered to the side of the tooth rubber portions 2. The tooth portion reinforcing member 5 has a short fiber bound layer 8 formed on one face of a base woven fabric 7 by melting and solidifying the olefin short fiber group and a coat rubber layer 9 deposited and formed on the other face. The short fiber bound layer 8 is located on the outermost faces of the tooth rubber portions 2 while being exposed thereto. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a toothed belt and a tooth part reinforcing material used therefor, and more particularly, to a toothed belt having improved tooth chip resistance and a tooth part reinforcing material used therefor.

  Toothed belts that drive camshafts, injection pumps, oil pumps, water pumps, etc., for automobile engines, increase the load on the belt and increase the ambient temperature as the engine room becomes more compact with higher engine output Since the use environment of toothed belts has become particularly severe in recent years, further improvement in durability is required. Further, in recent years, a drive system using a belt has been adopted for driving a rear wheel of a large-sized motorcycle in response to quietness and maintenance-free performance from the conventional chain or shaft drive. Further, for toothed belts used for general industries, it is required to extend the replacement period for high load driving such as injection molding machines.

  The failure modes of toothed belts are broadly divided into belt cutting due to bending fatigue of the core wire and cracking due to insufficient heat resistance of rubber, overload, insufficient heat resistance of tooth cloth and tooth rubber, and tooth chipping due to wear of tooth cloth. Is done. With respect to belt cutting due to bending fatigue of the core wire and insufficient heat resistance of the rubber, improvement of the core wire material, the diameter of the core wire configuration, etc., and improvement of the heat resistance of the core wire treating agent have been implemented. In addition, with respect to improving the heat resistance of rubber, failures have decreased due to the use of hydrogenated nitrile rubber.

  In particular, an engine in which a high load is applied to the belt, and a toothed belt for driving a rear wheel drive or an industrial drive device for a two-wheeled vehicle, the pulley shaft is bent due to the high load, and the belt is offset, causing the pulley to move. Abnormal wear on the side surface of the belt due to friction with the flange or the like, cutting due to damage on the side surface, and chipping are likely to occur. Furthermore, the belt is stretched by a high load, the auto tensioner does not operate or the belt tension is lowered due to the biaxial drive, and a proper load is not applied to the belt, thereby causing a phenomenon that hinders normal operation of the engine.

  For this reason, the surface of the toothed belt meshing with the pulley teeth is treated with fluorine resin, layered graphite, or the like, which acts to reduce the friction coefficient, against wear and damage on the belt side and belt elongation. In addition, although the investigation of the core wire material has been carried out, a sufficient improvement measure has not yet been found.

In Patent Document 1, a warp and / or weft is made of a woven fabric made of ultrahigh molecular weight polyethylene fibers, melted at the time of vulcanization, and a coating of ultrahigh molecular weight polyethylene is formed on the tooth surface. It is described that a coefficient and excellent wear resistance are exhibited.
Japanese Patent Publication No. 8-30514

  As described above, in Patent Document 1, a woven fabric using ultrahigh molecular weight polyethylene fibers for one or both of the warp and the weft is used for the tooth cloth, the fibers are melted during vulcanization, and the surface of the tooth portion is made extremely high. The film was made of a molecular weight polyethylene to provide a low friction surface and imparted excellent wear resistance. In this way, a coating of ultra high molecular weight polyethylene is formed on the tooth surface, but the entire tooth cloth becomes ultra high molecular weight polyethylene that is solidified after melting, resulting in increased rigidity, and as a result, the tooth portion is impact resistant. It could not be said that it was excellent.

  The present invention has been made in view of the above problems, and in a toothed belt in which the surface of the tooth rubber part is coated with a fiber fabric, the short fiber formed by melting and solidifying an olefinic short fiber group on the surface of the tooth rubber part. An object of the present invention is to provide a toothed belt that contributes to the improvement of the belt life by providing a bonding layer and reducing the frictional resistance over a long period of time, and a tooth part reinforcing material used therefor.

  The invention according to claim 1 includes a back rubber part in which a core wire is embedded, and a plurality of tooth rubber parts arranged at a predetermined pitch in the belt longitudinal direction on the back rubber part, and the surface of the tooth rubber part In the toothed belt having the tooth part reinforcing material attached thereto, a short fiber bonding layer formed by melting and solidifying the olefinic short fiber group on one surface of the base fabric in which the tooth part reinforcing material is made of a woven fabric, and the other A coat rubber layer is adhered to the surface, and the short fiber bonding layer is located in a state exposed on the outermost surface of the tooth rubber portion. The short fiber bonding layer becomes a resin film, has excellent wear resistance, and improves the durability of the tooth rubber part.

  The invention according to claim 2 of the present application is a toothed belt in which the short fiber bonding layer includes at least ultra high molecular weight polyethylene short fibers as a group of olefinic short fibers. The short fiber bonding layer becomes a surface having a low coefficient of friction due to the presence of the ultrahigh molecular weight polyethylene short fibers, has a further excellent wear resistance, and can improve the durability of the tooth rubber part.

  The invention described in claim 3 of the present application is a toothed belt in which the short fiber bonding layer includes an ultra-high molecular weight polyethylene short fiber as a group of olefinic short fibers and a short fiber having a melting point lower than that, and is claimed in claim 4. The invention is a toothed belt in which the low-melting short fiber is at least one fiber selected from polyethylene and polypropylene, and the short fiber without melting the ultrahigh molecular weight polyethylene short fiber by melting the low melting short fiber It can be secured to the tie layer. The invention according to claim 5 is a toothed belt in which an adhesive layer is impregnated and adhered to the base fabric, and the base fabric adheres well to the tooth rubber portion.

  The invention according to claim 6 of the present application is a tooth part reinforcing material in which a short fiber assembly layer containing short fibers meltable at a vulcanization temperature is formed on one side of a base fabric made of a woven fabric, and a coat rubber layer is formed on the other side. It is. The short fibers of the short fiber assembly layer are melted at a vulcanization temperature (150 to 170 ° C.) to form a film, thereby providing a tooth part reinforcing material having excellent wear resistance.

  In the invention according to claims 7 to 10 of the present invention, when the short fiber aggregate layer contains at least an ultrahigh molecular weight polyethylene short fiber as an olefinic short fiber group, the short fiber aggregate layer has an ultrahigh molecular weight polyethylene as an olefinic short fiber group. When short fibers and short fibers having a lower melting point are included, when the low melting point short fibers are at least one fiber selected from polyethylene and polypropylene, the short fiber assembly layer is a non-woven fabric. The aggregate layer becomes a short fiber bonded layer having a low friction coefficient due to the presence of ultrahigh molecular weight polyethylene short fibers, and has a further excellent wear resistance, and becomes a tooth part reinforcing material that improves the durability of the tooth rubber part.

  The invention according to claim 11 of the present application is a tooth portion reinforcing material in which an adhesive layer is impregnated and adhered to the base fabric, and the adhesive force between the base fabric and the rubber member (coat rubber layer or tooth rubber layer) is improved.

  In the toothed belt of the present invention, the short fiber bonding layer has excellent wear resistance, improves the durability of the tooth rubber portion, and the short fiber bonding layer contains at least ultra high molecular weight polyethylene short fibers. The surface has a lower coefficient of friction, has even better wear resistance, and improves the durability of the tooth rubber part. Further, the tooth part reinforcing material also has a better abrasion resistance by melting the short fibers of the short fiber assembly layer at a vulcanization temperature (150 to 170 ° C.) to form a short fiber bonding layer.

  Hereinafter, the toothed belt of the present invention will be described with reference to the drawings. FIG. 1 is a partial front view of a toothed belt according to the present embodiment, FIG. 2 is a cross-sectional view taken along line AA of FIG. 1, and FIG. 3 is a cross-sectional view of a tooth portion reinforcing material.

  The toothed belt 1 includes a plurality of tooth rubber portions 2 arranged at predetermined intervals along the longitudinal direction, a back rubber portion 4 continuous with the tooth rubber portion 2, a core wire 3 embedded in the back rubber portion 4, and teeth. It has the tooth | gear part reinforcing material 5 coat | covered on the surface of the rubber part 2. As shown in FIG.

  As shown in FIG. 2, the tooth reinforcing material 5 has a short fiber bonding layer 8 formed by melting and solidifying an olefinic short fiber group on one surface of a base fabric 7 made of a woven fabric impregnated with an adhesive layer 6. A coat rubber layer 9 is adhered and formed on the other surface, and the short fiber bonding layer 8 is located in an exposed state on the outermost surface of the tooth rubber portion 2. Thereby, the said short fiber coupling layer 8 has the outstanding abrasion resistance, and can improve the durability of a tooth rubber part.

  The tooth part reinforcing material 5 is a fabric in which the base fabric 7 is woven by weaving wefts 10 extending in the longitudinal direction of the belt and warps 11 extending in the width direction of the belt, and resorcin, formaldehyde, rubber A solid substance of latex treatment liquid (RFL treatment liquid) or an adhesive layer 6 in which the solid substance and a solid substance of rubber paste are laminated are impregnated and adhered. The olefinic short fiber group cut by the short fiber bonding layer 8 is attached to one surface of the base fabric 7 by a physical means such as a needle punch or a chemical method. The short fibers formed by melting from (150 to 170 ° C.) are partially melted and solidified to form a mat-like short fiber bonding layer 8 in which the short fibers are bonded to each other.

  The mat-like short fiber bonding layer 8 includes at least an ultrahigh molecular weight polyethylene short fiber which is a group of olefinic short fibers, and this polymer returns to its original state after cooling even when heated to a melting point of 140 ° C. or higher. It is characterized by wear resistance and low coefficient of friction. The molecular weight of the polymer is 100,000 to 1,500,000, preferably 300,000 to 1,200,000 when expressed by a viscosity method. When it is 100,000 or less, the viscosity at the time of vulcanization falls extremely. On the other hand, if it is 1.5 million or more, the resin cannot be produced.

  The short fiber bonding layer 8 includes, in addition to the ultrahigh molecular weight polyethylene short fibers, polyethylene, polypropylene, etc., which are low melting point short fibers having a lower melting point, and each short fiber is partially divided depending on the temperature during vulcanization. Alternatively, the whole is melted to form a thin film and adheres to the base fabric 7. The added amount of the ultrahigh molecular weight polyethylene short fiber is 50% or more, preferably 75% or more.

  The tooth reinforcing material 5 is obtained by integrating a short fiber assembly layer 12 (nonwoven fabric) specifically composed of ultrahigh molecular weight polyethylene short fibers with a base fabric 7 by a physical method such as needle punching. For example, the short fiber assembly layer 12 (nonwoven fabric) made of ultrahigh molecular weight polyethylene short fibers and a base fabric made of nylon fibers or aramid fibers are physically bonded by a needle punch. Furthermore, when the ultrahigh molecular weight polyethylene short fibers are melted during vulcanization for producing the belt, an anchor effect is generated by flowing into the base fabric 7, and the base fabric 7 is more firmly bonded.

  A specific method of manufacturing the tooth reinforcing material 5 is as follows. After impregnating the base fabric 7, which is a fiber fabric formed by the weft 10 and the warp 11, into the RFL treatment liquid, the first treatment liquid is passed through a pair of pressure rolls. Adjust the amount of adhesion. Then, it heat-drys for 1-3 minutes at 150-200 degreeC. The adhesive layer 6 made of an RFL layer is a rubber component of a solid rubber obtained by heating and drying a rubber latex, and a resin-based adhesive component of an initial condensate of resorcin and formalin.

  Further, after the base fabric 7 is impregnated and adhered to the rubber adhesive, the adhesive layer 6 is formed by adjusting the adhesion amount of the rubber paste through a pair of pressure rolls. Thereafter, the short fiber assembly layer 12 (nonwoven fabric) is laminated. In this lamination step, the short fiber assembly layer 12 (nonwoven fabric) using short fibers is laminated and integrated on one surface of the base fabric 7 by physical means such as needle punching. Then, the base fabric 7 to which the short fiber assembly layer 12 (nonwoven fabric) is attached is passed through a pair of pressure rolls, and the other surface of the base fabric is coated with an unvulcanized rubber having a thickness of 0.2 to 1.0 mm. This is heated and dried at 150 to 180 ° C. for 1 to 3 minutes to form the coated rubber layer 9 on the side opposite to the short fiber assembly layer 12 (nonwoven fabric).

  Moreover, as a method of forming the short fiber aggregated layer 12, for example, the short fibers are attached to the surface of the adhesive layer 6 by dropping or spraying the short fibers on the adhesive layer 6, and then natural or heat drying is performed. . As another method, an electric field is formed by applying a voltage to the electrode of the electrostatic flocking machine, and a surface in which the surface is electrodeposited. The short fibers are supplied, fly and stuck to the surface of the adhesive layer 6 to attach the short fibers, and then natural or heat drying is performed. In consideration of density and uniformity, electrostatic flocking is desirable.

  The RFL treatment liquid is a mixture of an initial condensate of resorcin and formalin and a rubber latex. In this case, the molar ratio of resorcin and formalin is 3/1 to 1/3 in order to increase the adhesive force. Is preferred. The initial condensate of resorcin and formalin is a mixture of rubber latex and rubber latex such that the resin content is 5 to 50 parts by weight with respect to 100 parts by weight of rubber latex.

  The rubber latex forming the RFL treatment liquid includes styrene / butadiene / vinylpyridine terpolymer (VP), styrene butadiene copolymer (SBR), chloroprene (CR), acrylonitrile butadiene copolymer (NBR), hydrogen. One kind or a blend of two or more kinds of added NBR (H-NBR), chlorosulfonated polyethylene (CSM), natural rubber and the like is used.

  As the material of the fiber fabric formed by the weft 10 and the warp 11 of the base fabric 7, any of nylon, aramid, polyester, polybenzoxazole, cotton, etc., or a combination thereof can be used. The form of the fiber may be either a filament yarn or a spun yarn, and may be any of a single composition twisted yarn, a mixed twisted yarn, or a mixed spun yarn.

  Moreover, as a material of the fiber which forms the nonwoven fabric which is the short fiber assembly layer 12, any of nylon, aramid, polyester, polybenzoxazole, cotton, etc., or these combination is employable. Further, the fiber may be subjected to RFL treatment.

  When the usage environment is a high temperature of 100 ° C. or higher and a long life of 150,000 km or more is required, H-NBR is used for the belt body. For the RFL treatment liquid impregnated and adhered to the short fiber assembly layer 12, a long life can be achieved by using a normal blend of H-NBR and CSM latex and VP latex. On the other hand, in the case of a general industrial toothed belt using natural rubber and SBR for the belt body, the RFL treatment liquid impregnated and adhered to the short fiber assembly layer 12 includes VP latex, SBR latex, and these Blends can be used.

  In addition, there is no restriction | limiting in particular in the material of the rubber compound which forms a belt main body, A suitable thing is suitably selected according to use conditions. In the case of toothed belts for automobile engines and various engines, H-NBR, CR, CSM, etc. having heat resistance and oil resistance are used. In addition to H-NBR, CR, and CSM, toothed belts used for general industrial machinery include NBR, ethylene propylene diene monomer (EPDM), ethylene propylene copolymer (EPR), SBR, isoprene rubber (IR), natural Any of rubber (NR), fluorine rubber, silicon rubber and the like can be used. In the case of such a toothed belt, the use of the tooth cloth described in FIG. 1 is effective.

  Moreover, there is no restriction | limiting in the core wire 3 embed | buried inside a belt main body, Generally a glass core wire, an aramid core wire, and a carbon fiber core wire are used. Further, any twisted cord composed of polybenzoxazole, polyparaphenylene naphthalate, polyester, acrylic, carbon, and steel can be used. The composition of the glass core wire may be either E glass or S glass (high strength glass), and is not limited by the thickness of the filament, the number of converged filaments and the number of strands. Further, it is not limited to a sizing agent, RFL, overcoat agent or the like used as an adhesive treatment agent or a protective material for a glass filament during bending. On the other hand, the aramid core is not limited by the difference in the molecular structure of the material, the configuration of the core, the size of the filament, or the difference in the adhesive treatment agent. Similarly, there are no special restrictions on the twisted cords of the cords made of other compositions.

  The toothed belt manufacturing method includes a method in which the processed tooth portion reinforcing material 5 is machined into a cylindrical shape and inserted into a mold having alternately groove portions and convex portions, and then a cord made of a cord. The unvulcanized rubber sheet which forms a belt main body is wound on it. Then, after covering a jacket, it is transferred to a vulcanization process. At the time of vulcanization, an unvulcanized rubber sheet is poured into the groove portion together with the tooth portion reinforcing material 5, and the tooth portion reinforcing material 5 is vulcanized integrally with the belt body to produce a belt sleeve. After the vulcanized belt sleeve is removed from the mold, the belt sleeve is attached to two shafts of a cutting machine, and while being rotated by applying tension, it is cut into a predetermined width by a cutter to produce a toothed belt.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to this Example, It can change suitably in the range which does not deviate from the objective.

  As a base fabric for tooth reinforcement, 220 dtex filament yarn, which is a 1.65 dtex para-aramid filament filament converged on warp yarn, and technola 220 dtex / 2 yarns, Conex 30th yarn / 1 yarn (spun yarn) ), A twisted yarn composed of 154 dtex / spandex, and a woven fabric of a 2/2 twill fabric composed of a weaving structure (warp 110/5 cm, weft 120/5 cm) was used. After weaving, the canvas was vibrated in water to shrink it to about ½ width of the weaving width to obtain a tooth reinforcement.

  Table 1 shows the rubber composition used for the tooth rubber part and the back rubber part, and Table 2 shows the RFL treatment liquid. As the short fiber aggregate layer of the base fabric, ultra high molecular weight polyethylene short fibers having a basis weight shown in Table 3 were used.

  The base fabric was immersed in an RFL treatment solution, dried at 120 ° C., heat-treated at 180 ° C. for 2 minutes, immersed in rubber paste, and dried at 80 ° C. Next, the non-woven fabric is attached to one surface of the base fabric with a needle punch, and the base fabric is further passed through a calender roll to form a coat rubber layer having a thickness of 0.5 mm on the surface opposite to the non-woven fabric. Dried to make a tooth reinforcement.

  Next, the above-mentioned tooth part reinforcing material was wound so that the nonwoven fabric faces a die having 120 teeth of ZBS teeth for belt preparation, and a pair of SZ twisted RFL liquid and hydrogenated nitrile rubber were dissolved in a solvent such as toluene. The core wire shown in Table 4 subjected to adhesion treatment with rubber paste and phenol resin was wound around the spiral with a predetermined tension at a pitch (1.4 mm / piece).

  The rubber sheet of Table 1 was affixed on this core wire. Further, after being put into a vulcanizing can and pressure vulcanized at 165 ° C. for 30 minutes by a normal press-fitting method to form a tooth profile, the back surface of the belt is polished to a certain thickness and cut to a certain width (30 mm). Thus, a toothed belt for traveling was obtained.

  The produced belt has a belt width of 15 mm, a belt tooth profile ZBS, a tooth number of 120 teeth, and a tooth pitch of 9.525 mm, and is normally displayed as 120 ZBS30. As the running test apparatus, a test apparatus having a layout including a 22-tooth crank pulley, a 44-tooth cam pulley, a 19-tooth water pump pulley, an eccentric pulley, and an idler is used. A running test was performed with an effective tension applied to the belt of 3,700 N and an initial tension of 350 N at a crank pulley rotational speed of 4,000 rpm. The results are shown in Table 5.

  From the results of Table 5, in Comparative Example 1, the belt breaks early, whereas in Examples 1 to 4 in which the short fiber bonding layer of the ultrahigh molecular weight polyethylene short fiber is formed on the surface of the base fabric, the belt breakage time is greatly increased. It can be seen that it was improved.

  The toothed belt of the present invention can be mounted to be used in a drive device for automobiles or general industries, and a toothed belt whose tooth part reinforcing material has improved tooth chip resistance can be obtained.

It is a front view of the toothed belt obtained by the manufacturing method of this invention. It is AA sectional drawing of FIG. Sectional drawing of a tooth | gear part reinforcing material is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Toothed belt 2 Tooth rubber part 3 Core wire 4 Back rubber part 5 Tooth part reinforcement 6 Adhesive layer 7 Base cloth 8 Short fiber bonding layer 9 Coat rubber layer 12 Short fiber assembly layer

Claims (11)

  A back rubber part with a core wire embedded therein and a plurality of tooth rubber parts arranged at a predetermined pitch in the belt longitudinal direction on the back rubber part, and a tooth part reinforcing material was stuck on the surface of the tooth rubber part In the toothed belt, a short fiber bonding layer formed by melting and solidifying a group of olefinic short fibers is formed on one surface of a base fabric in which the tooth part reinforcing material is a woven fabric, and a coat rubber layer is formed on the other surface. A toothed belt, wherein the short fiber bonding layer is located in a state of being exposed on the outermost surface of the tooth rubber portion.   The toothed belt according to claim 1, wherein the short fiber bonding layer includes at least ultra high molecular weight polyethylene short fibers as a group of olefinic short fibers.   The tooth belt according to claim 1, wherein the short fiber bonding layer includes an ultrahigh molecular weight polyethylene short fiber as a group of olefinic short fibers and a short fiber having a melting point lower than that.   The toothed belt according to claim 3, wherein the low melting point short fibers are at least one fiber selected from polyethylene and polypropylene.   The toothed belt according to claim 1, wherein an adhesive layer is impregnated and adhered to the base fabric.   A tooth part reinforcing material that is adhered to the surface of the tooth rubber part of the toothed belt, and a short fiber assembly layer containing an olefin-based short fiber group that can be melted at a vulcanization temperature on one surface of a base fabric made of a woven fabric, And the tooth | gear part reinforcing material characterized by adhering and forming the coat rubber layer on the other surface.   The tooth part reinforcing material according to claim 6, wherein the short fiber assembly layer includes at least ultra high molecular weight polyethylene short fibers as a group of olefinic short fibers.   The tooth part reinforcing material according to claim 6 or 7, wherein the short fiber aggregate layer includes an ultrahigh molecular weight polyethylene short fiber and a short fiber having a melting point lower than that of the olefinic short fiber group.   The tooth part reinforcing material according to claim 8, wherein the low melting point short fibers are at least one fiber selected from polyethylene and polypropylene.   The tooth part reinforcing material according to claim 6, wherein the short fiber assembly layer is a nonwoven fabric. The tooth | gear part reinforcing material of Claim 6 thru | or 10 by which the contact bonding layer is impregnated and adhered to the base fabric.

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