JP2008208997A - Power transmitting belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power transmitting belt which precludes popping-out of core wires exposed in the belt side-faces by suppressing untwisting of the core wires, and decreases occurrence of troubles such as turnover or break of the belt caused by the popping-out. <P>SOLUTION: The power transmitting belt having an expansion layer 4 and a compression layer 5 where the core wires 2 in spiral form are buried, and structured so that the side faces assume V-shape, wherein the core wires 2 are formed by immersing untwisted Aramid fibers in a resorcinol formalin latex solution, drying them, and gathering several pieces of these processed Aramid fibers and twining them together. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a power transmission belt that is a V-belt used in snowmobiles, scooters, buggy vehicles, and general industrial transmission belts, and more specifically, suppresses fraying of the core wire exposed on the belt side surface. The present invention relates to a power transmission belt that prevents a belt failure caused by pop-out.

  2. Description of the Related Art Conventionally, in a drive system in the mechanical field for scooters or general industries, a belt-type transmission that suspends a power transmission belt between a drive pulley and a driven pulley and changes the effective diameter of the pulley is used. . The power transmission belt used here does not have a cog part, or has a cog part in which a cog crest part and a cog valley part are alternately arranged in the compression rubber layer among the compression rubber layer and the stretch rubber layer, Examples include a configuration in which a core wire is embedded in an adhesive rubber layer, and is commercialized as a low edge belt such as a low edge belt, a low edge single cogged belt, or a low edge double cogged belt.

  Aramid fibers are widely used as the cores used to reinforce these belts, but these aramid fibers are high-strength, high-modulus organic fibers with good heat resistance and strength at high temperatures and high humidity. It has modulus retention and excellent dimensional stability in high temperature and high humidity, but on the other hand, it has poor adhesion to rubber compound, and also has bending fatigue when made into a rubber composite. Has a decision to be scarce.

  In particular, in the case of a cut edge type V-belt in which the cut surface of the fiber cord is exposed, there arises a problem of fraying or pop-out of the fiber protruding from the cut surface.

JP-A-5-44131 JP-A-6-337037

  In Patent Document 1, an aramid fiber filament that is bundled in a non-twisted manner is pretreated with an epoxy compound in order to improve the bending fatigue property and fraying property of a power transmission belt having an aramid fiber cord as a core. Aramid obtained by applying a plurality of bundled yarns subjected to the lower twist and then twisting the bundled yarns in the direction opposite to the direction of the lower twist, and subjecting the obtained twisted yarn cord to an RFL solution. The use of fiber cords is described.

  Similarly, in Patent Document 2, in order to improve the bending fatigue property and fraying property of a power transmission belt having an aramid fiber cord as a core, untwisted aramid fiber filaments with a liquid composed of an epoxy compound or an isocyanate compound are used. An aramid fiber cord that has been subjected to adhesion treatment, twisted into a lasso, bundled with at least two lumps, and then subjected to adhesion treatment with an RFL solution and / or rubber paste, and a twist coefficient within a predetermined range It is described that.

  However, if the RFL solution is not sufficiently impregnated, there is a problem that the core wire frays and pops out due to friction between the end surface of the core wire exposed on the belt side surface and the pulley, and the belt rolls over or cuts. It was.

  Accordingly, an object of the present invention is to provide a power transmission belt in which the binding of the core wires is increased so that the core wires are not easily frayed and problems such as pop-out are solved.

  In order to achieve the above object, according to claim 1 of the present invention, there is no use for power transmission in which a spiral core wire is embedded and has a stretch rubber layer and a compression rubber layer and the side surface has a V shape. A power transmission belt characterized in that a twisted fiber is immersed in a resorcin / formalin / latex solution and dried, and then a plurality of the treated fibers are collected and twisted, and used as the core wire.

  According to a second aspect of the present invention, there is provided the power transmission belt according to the first aspect of the present invention, wherein the belt is used after being twisted and further dipped in a resorcin / formalin / latex solution and dried.

  In Claim 3, it is set as the belt for power transmission of Claims 1-2 whose kind of fiber is an aramid fiber.

  According to the first aspect of the present invention, the adhesive treatment is performed with the RFL solution before twisting the filament of the fiber used for the core wire, and the core wire is constituted by sufficiently impregnating the fiber constituting the core wire with the RFL solution. Since the RFL solution is sufficiently infiltrated and applied to the fibers to be applied and the binding force between the filaments is increased, the core wire exposed on the side of the belt is less likely to fray even if it rubs against the pulley. It is possible to prevent a belt failure and make a belt having a long life.

  In claim 2, since the bonding process is further performed with the RFL solution after twisting, and the core wire is in a more tightly bound state, the effect of preventing fraying is greater. It can be.

  According to the third aspect of the present invention, the type of fiber is an aramid fiber, and the core wire using the aramid fiber, which is a fiber that is prone to fraying, can exhibit the effects of the present invention more remarkably.

  FIG. 1 shows a power transmission belt which is a V-belt with a low edge cog using an aramid core wire according to the present invention. In FIG. 1, a power transmission belt 1 is formed with an adhesive layer 3 in which a core wire 2 is embedded and an extension layer 4 in which a cover canvas is laminated, and a compression layer 5 is laminated below the adhesive layer 3. Has been placed.

  The rubber used for the adhesive layer 3, the stretch layer 4 and the compression layer 5 is natural rubber, styrene-butadiene rubber, chloroprene rubber, alkylated chlorosulfonated polyethylene, nitrile rubber, hydrogenated nitrile rubber, hydrogenated nitrile rubber and unsaturated. It consists of a single known rubber material such as a mixed polymer with a carboxylic acid metal salt or a suitable blend of these.

  The stretchable layer 4 formed on the adhesive layer 3 is formed by laminating a stretchable canvas 6 with a rubber woven from a bias canvas, a wide-angle canvas, or a woolen nylon warp and a normal weft. The material may be a wide-angle canvas made of polyester fiber, nylon fiber, etc., woven in plain weave, twill weave, satin weave, etc., and the crossing angle between warp and weft is about 90-120 °. The above-mentioned canvas is subjected to RFL treatment, and then the rubber composition is friction-coached to obtain a canvas with rubber. The RFL liquid is obtained by mixing an initial condensate of resorcin and formalin into a latex. Examples of the latex used here include chloroprene, styrene / butadiene / vinylpyridine terpolymer, hydrogenated nitrile, NBR, and the like.

  The compression layer 5 has a cog portion 7 with a constant pitch formed on the lower surface, and at least one horizontal suede canvas 8 is embedded in a corrugated shape along the shape of the cog portion. Reinforce the rigidity of. In the present invention, this horizontal suede canvas 8 is not essential and may not be arranged.

  Further, the compression layer 5 is mixed with short fibers 9 for reinforcement. Para-aramid fibers (trade names: Twaron, Kevlar, Technora) alone or para-aramid fibers and nylon, polyester, vinylon, cotton, meta Short fibers such as system aramid fibers (trade name: Conex) are mixed and oriented in the belt width direction. By mixing these short fibers while maintaining the orientation in the width direction of the belt, it is possible to increase the rigidity in the width direction of the belt and improve the wear resistance of the side surface of the belt.

  The addition amount of this short fiber is 5-40 mass parts with respect to 100 mass parts of rubber | gum, Preferably it is 8-15 mass parts.

  The short fiber 9 protrudes from the side surface of the compression layer 5, and the protruded fiber reduces the frictional force between the belt and the pulley to prevent rubber sticking and wear and reduce the sound generated by the belt slip. Can do.

  Further, a core wire 2 is embedded in the adhesive layer 3, and an aramid fiber is used as the core wire 2, but poly-p or m-benzamide, poly-p-phenylene terephthalamide, poly-m- Mention may be made of phenylene isophthalamide fibers.

  In order to embed the core 2 in rubber and use it as a belt tension body, the core and the rubber must be firmly bonded. The core wire is formed by twisting a plurality of filaments, and the plurality of filaments must be bundled. For those reasons, the rope used as the core wire is subjected to an adhesive treatment. Examples of the adhesion treatment include treatment with an RFL solution, treatment with a rubber paste, treatment with an isocyanate compound or an epoxy compound.

  In the present invention, prior to twisting the filaments, the treatment is performed with the RFL solution, and after the treatment with the RFL solution, the filaments are brought together and used as the core wire 2. If the treatment with the RFL liquid is performed after twisting, the RFL liquid cannot be impregnated into the inside of the twisted rope, and an insufficiently bonded part is created, resulting in a fraying of the rope, and the core wire is A pop-out that jumped out from the side of the belt occurred, leading to a breakdown such as the belt overturning or cutting. However, by performing the treatment with the RFL liquid prior to the twisting as described above, the RFL liquid can completely cover the surface of each filament, and the filaments constituting the approaching rope are firmly bonded to each other. And become a unit. Therefore, when used as a belt core, even if a part of the core is exposed on the side of the belt and repeatedly rubs against the pulley, fraying can be suppressed, and pop-out Failure due to can be prevented.

  In the present invention, it is an essential requirement to perform the RFL treatment in the state of the raw yarn before twisting, but it is also possible to perform the adhesion treatment with the RFL liquid again after twisting, and further fraying by doing so. The effect of suppressing the occurrence of this will be obtained.

  Twisting after processing with the RFL solution is a conventional method that has been conventionally performed. For example, a plurality of bundled filaments are twisted to make a small rope, and the small rope is bundled again. You can take a method such as applying an upper twist. As the RFL liquid, those conventionally used can be used.

  In the above description, an aramid fiber is taken as an example, but the type of fiber is not limited to an aramid fiber, and other examples include a polyamide fiber, a polyester fiber, a glass fiber, and a polyparaphenylene benzobisoxazole fiber. be able to. However, since the aramid fiber can be said to be a fiber that is prone to fraying, it can be said that this is an example in which the effect of the present invention appears more remarkably.

  In order to confirm the difference between the core wire subjected to the adhesion treatment with the RFL liquid before twisting and the core wire performed after twisting, V belts were produced by respective methods and subjected to a comparative test.

(Example 1)
As Example 1 of the present invention, an untwisted 1500 denier aramid fiber filament was immersed in an RFL solution, and then subjected to an adhesion treatment by heat treatment at 200 ° C. for 2 minutes. Three aramid fiber filaments subjected to the adhesion treatment with the RFL solution were bundled to give a lower twist, and four of them were further bundled to give an upper twist in a direction opposite to the direction of the lower twist to form a bundle of ropes. A low edge cog belt was produced using this rope as a core wire.

  As shown in FIG. 2, the belt is wound around a driving pulley of 80 mmφ and a driven pulley of 160 mmφ, and a tension pulley of 85 mmφ is brought into contact with the back of the belt so that the bending angle of the belt is 160 °. It was rotated at 1800 rpm, a 5 ps load was applied to the driven pulley, the ambient temperature was set to 70 ° C., and the time until the end of the life was measured. The results are shown in Table 1.

(Example 2)
As Example 2 of the present invention, an untreated cord of untwisted 1100 denier polyethylene terephthalate (PET) was prepared, immersed in an RFL solution, and then treated at 230 ° C. for 2 minutes. Three polyethylene terephthalate fiber filaments subjected to the adhesion treatment with the RFL solution were bundled to give a lower twist, and five of them were further bundled to give an upper twist in a direction opposite to the lower twist to form a bundle of people. A low edge cog belt was produced using this rope as a core wire.

  Further, this belt was also run with a pulley layout as shown in FIG. 2 in the same manner as in the example, and the time until the end of the life was measured. The results are shown in Table 1.

(Comparative Example 1)
As a belt of Comparative Example 1, a rope subjected to adhesion treatment in exactly the same manner as in Example except that an aramid fiber filament was subjected to a lower twist and an upper twist and then subjected to an adhesion treatment with an RFL solution was obtained. A low edge cog belt was produced as a wire.

  Further, this belt was also run with a pulley layout as shown in FIG. 2 in the same manner as in the example, and the time until the end of the life was measured. The results are shown in Table 1.

(Comparative Example 2)
As a belt of Comparative Example 2, a rope subjected to adhesion treatment in exactly the same manner as in Example was obtained except that the polyester fiber filament was subjected to a lower twist and an upper twist and then subjected to an adhesion treatment with an RFL solution. A low edge cog belt was produced as a wire.

  Further, this belt was also run with a pulley layout as shown in FIG. 2 in the same manner as in the example, and the time until the end of the life was measured. The results are shown in Table 1.

  As can be seen from the results in Table 1, in the examples in which both the aramid and the polyester fiber were subjected to the adhesion treatment with the RFL liquid prior to the twisting of the fiber filament, fraying of the core wire was suppressed, and cracks occurred in the cog valley portion of the belt. Has reached the end of its life. On the other hand, in the belt of the comparative example in which the RFL treatment was performed after twisting, the pop-out of the core wire occurred at an early stage, and the belt overturned and reached the end of its life, confirming the effect of the present invention.

  The present invention eliminates the fraying of the core wire and extends the life of the belt due to a failure such as pop-out, and can be used for a V-belt that can be used in power transmission applications such as agricultural machinery and motorcycles.

It is sectional drawing of the low edge cog belt which is 1 aspect of this invention. It is a schematic diagram which shows the pulley layout of a test.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Power transmission belt 2 Core wire 3 Adhesive layer 4 Stretch layer 5 Compression layer 6 Stretchable canvas 7 Cog part 8 Sudare canvas 9 Short fiber

Claims (3)

  For power transmission in which a spiral core wire is embedded to have a stretched rubber layer and a compressed rubber layer and the side surface has a V shape, the untwisted fibers are dipped in a resorcin / formalin / latex solution and dried, followed by the treatment. A power transmission belt, wherein a plurality of finished fibers collected and twisted are used as the core wire.   2. The power transmission belt according to claim 1, wherein the belt is a core wire that has been twisted and then dipped in a resorcin / formalin / latex solution and dried.   The power transmission belt according to claim 1 or 2, wherein the fiber is an aramid fiber.

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