JP2007120759A - Transmission belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve wear resistance and sounding resistance without degrading a durable life of a belt like the conventional case of depending on a cross linking agent and a reinforcing agent and to reduce waste in manufacture. <P>SOLUTION: This transmission belt comprises an adhesive rubber layer with core wires embedded extending in the longitudinal direction of the belt, and an adjoining compressed rubber layer, wherein the compressed rubber layer is formed of a rubber composition in which powder rubber obtained by pulverizing cross-linked rubber is compounded at the compounding amount of 40 pts.mass or less to 100 pts.mass of ethylene-α-olefine elastomer. The powder rubber is waste produced in manufacturing the transmission belt. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a power transmission belt, and more particularly, to a power transmission belt that can reduce the amount of waste in the manufacturing process and has wear resistance and bending resistance.

  The following example is given as a manufacturing method of a low edge V belt which is a kind of friction transmission belt. First, a cover canvas is wrapped around the circumferential surface of a cylindrical molding drum, a compressed rubber layer and an adhesive rubber layer composite are wound around, and then a cord made of a rope is spirally spun onto this, and an adhesive rubber layer, Wrap the cover canvas sequentially. This is vulcanized with a vulcanizing can to obtain a vulcanized sleeve. The obtained vulcanized sleeve is rotated to a predetermined width by two cutters and finished into a low edge V-belt.

  Moreover, the following example is mentioned as a manufacturing method of V ribbed belt which is another friction power transmission belt. First, a cover canvas is wound around the circumferential surface of a cylindrical molding drum, and an adhesive rubber layer is wound thereon. Then, a cord made of a rope is spun into a spiral shape, and an adhesive rubber layer and a compressed rubber layer are further wound. This is vulcanized with a vulcanizing can to obtain a vulcanized sleeve. While rotating the vulcanized sleeve thus obtained, the grindstone with the V-groove rotated at high speed is slowly lowered and ground to obtain the sleeve with the groove. While rotating this, it is cut into a predetermined width by a cutter to obtain a V-ribbed belt.

  In the manufacturing method of the low edge V-belt, a large amount of unnecessary waste cut by a cutter is generated between the low-edge V belts, and a large amount of grinding waste is generated also in the manufacturing method of the V-ribbed belt.

  The generated waste is generally landfilled as industrial waste or used as fuel, but landfilling is not preferred because of the risk of soil and marine contamination. Further, when used as fuel, carbon dioxide is generated, which causes a problem of global warming.

In order to solve such a problem, Patent Document 1 discloses a method in which recycled rubber obtained by recycling generated waste is added as a recycled material to a transmission belt compound.
Japanese Patent No. 3553371

  However, when recycled rubber is added, there is a problem that the rubber elastic modulus decreases, wear resistance decreases, and the belt life is shortened.

  On the other hand, chloroprene rubber has been mainly used as a rubber material constituting the transmission belt. However, the rubber hardens early in a high temperature atmosphere, and for example, there is a problem that cracks occur in the rib portion of the V-ribbed belt.

  Although some improvement has been made against such an early failure phenomenon of the belt, as long as chloroprene is used, the heat resistance is limited, and at present, sufficient heat resistance has not been achieved. For this reason, it has become common to use ethylene-α-olefin elastomers having excellent heat resistance in place of chloroprene rubber.

  In recent engines, lean combustion is used to improve fuel economy and reduce exhaust emissions, and engine rotation fluctuations and vibrations are larger than before, and the auxiliary belt has a small pulley and a large refraction angle layout due to serpentine. Thus, the load on the belt is further increased.

  In general, it is possible to increase the crosslinking density by increasing the crosslinking agent, or to improve the belt performance such as wear resistance by increasing the amount of reinforcing agent such as carbon black. Then, the rubber becomes brittle, and the method of increasing the amount of carbon black has a problem that the heat generation of the rubber increases and the durability life is reduced.

  The present invention solves such problems, and provides a transmission belt that improves wear resistance without reducing the durable life of the belt, and further reduces waste during production. Objective.

  The invention according to claim 1 of the present application is the transmission belt comprising the adhesive rubber layer in which the core wire extending in the longitudinal direction of the belt is embedded and the compressed rubber layer adjacent thereto, wherein the compressed rubber layer is an ethylene-α-olefin elastomer 100. The power transmission belt is characterized in that it is formed from a rubber composition in which a powder rubber obtained by pulverizing a crosslinked rubber is blended in an amount of 40 parts by mass or less with respect to parts by mass.

  The invention according to claim 2 is the power transmission belt according to claim 1, wherein the powder rubber has an average particle diameter of 10 μm to 500 μm.

  The invention according to claim 3 is characterized in that the crosslinked rubber is at least selected from ethylene-α-olefin elastomer, chloroprene rubber, natural rubber, styrene butadiene rubber, acrylonitrile butadiene rubber, chlorosulfonated polyethylene rubber, and alkylated chlorosulfonated polyethylene rubber. The power transmission belt according to claim 1, wherein the power transmission belt is a crosslinked rubber mainly composed of one kind.

A fourth aspect of the present invention is the transmission belt according to any one of the first to third aspects, wherein the powder rubber is a waste generated when the transmission belt is manufactured.

  The invention according to claim 5 is the transmission belt according to any one of claims 1 to 4, wherein the transmission belt is a V-ribbed belt having a plurality of rib portions extending in the longitudinal direction of the belt in the compressed rubber layer.

  According to the invention described in each claim of the present application, it is possible to provide a power transmission belt that can improve wear resistance and sound generation resistance without reducing the durable life of the belt, and further reduce waste during production. Can do.

  FIG. 1 shows a V-ribbed belt as an example of a transmission belt according to the present invention. The V-ribbed belt 1 has a core 2 made of a fiber cord embedded in an adhesive rubber layer 3 and has a compressed rubber layer 4 below it. The compressed rubber layer 4 is provided with a plurality of ribs having a substantially trapezoidal cross section extending in the belt longitudinal direction, and a cover canvas 5 is laminated on the belt surface.

  The compressed rubber layer 4 is made of a rubber composition in which a powder rubber obtained by pulverizing a crosslinked rubber is blended in an amount of 40 parts by mass or less with respect to 100 parts by mass of the ethylene-α-olefin elastomer. The ethylene-α-olefin elastomer is a copolymer of ethylene and α-olefin (propylene, butene, hexene, octene, etc.), or a copolymer of ethylene, the above α-olefin, and a non-conjugated diene. Examples thereof include rubbers such as ethylene-propylene rubber (EPM) and ethylene-propylene-diene terpolymer (EPDM). Examples of the diene component include non-conjugated dienes having 5 to 15 carbon atoms such as ethylidene norbornene, dicyclopentadiene, 1,4-hexadiene, cyclooctadiene, and methylene norbornene.

  Powdered rubber obtained by pulverizing crosslinked rubber (hereinafter simply referred to as powdered rubber) is an ethylene-α-olefin elastomer, chloroprene rubber, natural rubber, styrene butadiene rubber, acrylonitrile butadiene rubber, chlorosulfonated polyethylene rubber, alkyl Grinding scraps made of a crosslinked rubber mainly composed of at least one selected from chlorinated chlorosulfonated polyethylene rubber and generated in the manufacturing process of the V-ribbed belt and discarded as an unnecessary object can be used as they are. In the case of unnecessary materials other than grinding scraps, for example, ring-shaped scraps generated in the production of a low-edge V-belt, which will be described later, powder rubber can be obtained at room temperature or by freeze grinding.

Among the above, the type of cross-linked rubber is preferably a cross-linked rubber mainly composed of ethylene-α-olefin elastomer or chloroprene rubber, and is difficult to separate, for example, when it is obtained in a state where both grinding scraps are mixed as waste. In some cases, a mixture of both may be used. In addition, since the crosslinked rubber which has a chloroprene rubber as a main component is excellent in hydrophilicity, there exists an effect which improves the transmission performance and sound-proofing property at the time of wetness.

  Powder rubber is mix | blended with the compounding quantity of 40 mass parts or less with respect to 100 mass parts of ethylene-alpha-olefin elastomers. If the blending amount exceeds 40 parts by mass, problems relating to processability such as a decrease in the adhesiveness of the rubber sheet constituting the compressed rubber layer and a deterioration in the surface state occur. In order to obtain the effect of improving the wear resistance, the blending amount of the powder rubber is required to be at least 5 parts by mass, but considering the reduction of waste, the blending amount of the powder rubber is 40 parts by mass. It is desirable to have as much as possible in the following. Since the powder rubber is pulverized, bonding is likely to occur at the interface with the unvulcanized rubber, thereby providing a reinforcing effect and improving the wear resistance of the transmission belt.

  The average particle diameter of the powder rubber is set to 10 μm to 500 μm. When the average particle size is 10 μm or less, dispersion in the rubber is deteriorated. If it exceeds 500 μm, the reinforcing effect cannot be obtained, and not only the strength and abrasion resistance of the rubber composition are lowered, but also the crack life is likely to occur from the interface between the new rubber and the powder rubber, so the belt life is reduced. There is a problem.

  Moreover, it is desirable that an organic peroxide is blended in the rubber composition as a crosslinking agent. Examples of the organic peroxide include dicumyl peroxide, di-t-butyl peroxide, t-butylcumyl peroxide, benzoyl peroxide, 1,3-bis (t-butylperoxyisopropyl) benzene, 2,5 -Dimethyl-2,5-di (t-butylperoxy) hexyne-3,2,5-dimethyl-2,5- (benzoylperoxy) hexane, 2,5-dimethyl-2,5-mono (t- Butyl peroxy) hexane and the like. This organic peroxide is preferably used alone or as a mixture in the range of 0.5 to 8 parts by mass with respect to 100 parts by mass of rubber.

  Furthermore, the rubber composition may contain 0.5 to 13 parts by mass of N, N′-m-phenylene dimaleimide with respect to 100 parts by mass of the rubber component. N, N'-m-phenylene dimaleimide acts as a co-crosslinking agent, and if it is less than 0.5 parts by mass, the effect of addition is not remarkable, and if it exceeds 13 parts by mass, the tearing force and the adhesive force are rapidly reduced.

  In addition, the compressed rubber layer 4 is mixed with short fibers made of nylon 6, nylon 66, polyester, cotton, and aramid to improve the side pressure resistance of the compressed rubber layer, and the compressed rubber layer is a surface in contact with the pulley. The surface is polished by a grinder to project the short fibers. The friction coefficient on the surface of the compressed rubber layer is lowered, and noise during belt running is reduced. Especially, when at least one of an aramid short fiber and a nylon short fiber is included, a rubber compound capable of maintaining a low friction coefficient for a long time can be obtained.

  For the compressed rubber layer 4, other usual rubbers such as carbon black and reinforcing agents such as silica, fillers such as calcium carbonate and talc, plasticizers, stabilizers, processing aids, and coloring agents as necessary. What is used for the blend is blended.

  As the core 2, polyester fiber, aramid fiber, and glass fiber are used. Among them, the total number of deniers obtained by twisting together polyester fiber filaments having ethylene-2,6-naphthalate as a main constituent unit is 4,000 to 8, A cord subjected to adhesion treatment of 000 is preferable in order to reduce the belt slip ratio and extend the belt life. The number of upper twists of this cord is 10 to 23/10 cm, and the number of lower twists is 17 to 38/10 cm. When the total denier is less than 4,000, the modulus and strength of the cord are too low. When the total denier is more than 8,000, the belt becomes thick and the bending fatigue property is deteriorated.

  Ethylene-2,6-naphthalate is usually synthesized by polycondensing naphthalene-2,6-dicarboxylic acid or an ester-forming derivative thereof with ethylene glycol in the presence of a catalyst under suitable conditions. At this time, if one or more appropriate third components are added before the polymerization of ethylene-2,6-naphthalate is completed, a copolymer polyester is synthesized.

  The core 2 is subjected to an adhesion treatment for the purpose of improving the adhesion to rubber. As such an adhesion treatment, the fibers are generally immersed in a resorcin-formaldehyde-latex (RFL) solution and then dried by heating to form a uniform adhesion layer on the surface. However, the present invention is not limited to this, and there is a method of performing a pretreatment with an epoxy or isocyanate compound and then treating with an RFL solution.

  The cord subjected to the bonding treatment can be finished into a belt having a high modulus by setting the spinning pitch, that is, the winding pitch of the core wire to 1.0 to 1.3 mm. If it is less than 1.0 mm, the cord cannot ride on the adjacent cord and cannot be wound. On the other hand, if it exceeds 1.3 mm, the modulus of the belt gradually decreases.

  The adhesive rubber layer 3 has heat resistance, and the same kind of rubber as the compressed rubber layer 4 is used.

  The cover canvas 5 is a cloth woven into plain weave, twill weave, satin weave, etc. using yarns made of cotton, polyamide, polyethylene terephthalate and aramid fibers. Of course, cover canvas may not be used.

  A typical manufacturing method of the V-ribbed belt is as follows. First, a canvas and an adhesive rubber layer are wound around the circumferential surface of a cylindrical molding drum, and then a cord made of a cord is spun into a spiral shape, and then an adhesive rubber layer and a compressed rubber layer are wound in order. After obtaining a laminated body, this is bridge | crosslinked and a sleeve is obtained.

  Next, the bridging sleeve is hung on the driving roll and the driven roll and travels under a predetermined tension, and the rotated grinding wheel is moved so as to abut against the traveling bridging sleeve and the compressed rubber layer of the bridging sleeve The surface is polished with 3 to 100 grooves at a time.

  The thus obtained bridging sleeve is removed from the driving roll and the driven roll, the bridging sleeve is hung on the other driving roll and the driven roll, traveled, cut into a predetermined width by a cutter, and each V-ribbed belt. Finish.

  In addition to the above-described V-ribbed belt, the transmission belt of the present invention includes a low-edge V-belt 21 in which a rubber canvas 22 is attached only to the upper and lower surfaces of the belt as shown in FIG. The belt 21 has a core wire 23 embedded in an adhesive rubber layer 24 and has a compression rubber layer 26 which is an elastic body layer on the lower side thereof. The compressed rubber layer 26 may be provided with cogs at predetermined intervals along the longitudinal direction.

(Examples 1-2)
Powder rubber was compounded in an amount shown in Table 1 with respect to 100 parts by mass of the ethylene-α-olefin elastomer, and kneaded with a closed kneader. The kneaded rubber was vulcanized at 165 ° C. for 30 minutes as a sheet having a predetermined thickness by a calender roll. The hardness (JIS-A) of the obtained vulcanized rubber was measured according to JIS K6253, the elongation EB at cutting was measured according to JIS K6251, and the stress M100 at 100% elongation was measured according to JIS K6251. Moreover, the surface state and adhesiveness were evaluated as processability evaluation of an unvulcanized rubber sheet. The evaluation results are shown in Table 1. In the evaluation of processability, ○ indicates that the surface state of the seated rubber sheet is good and the adhesiveness of the sheet is also good, Δ indicates that the rubber sheet has low adhesiveness, × indicates that the surface state of the rubber sheet is poor, The case where adhesiveness is low is shown.

Using the obtained unvulcanized rubber sheet as a compressed rubber layer, a V-ribbed belt with a circumference of 1100 mm was prepared, evaluated for wear rate by 6% slip test, evaluated for durability by high-temperature durability running test, and belt transmission performance test. The transmission torque during drying and water wetting was evaluated, and the sound generation characteristics during drying and water wetting were evaluated by a sound generation test.

(6% slip test)
Drive pulley (diameter 80mm), driven pulley (diameter 80mm), and tension pulley (diameter 120mm) are arranged, V-ribbed belt is hung on each pulley, belt wrapping angle around tension pulley is 90 degrees, room temperature condition Below, it was run for 24 hours while automatically adjusting the belt tension so that the rotational speed of the driving pulley was 3,300 rpm, the torque of the driven pulley was 0.7 kg · m, and the belt slip ratio was 6%. The belt weight before and after the running test was measured, and the belt weight loss (belt weight before running−belt weight after running) divided by the belt weight before running was calculated as the wear rate. The results are shown in Table 1.

(High temperature durability test)
A drive pulley (120 mm in diameter), a driven pulley (120 mm in diameter), and a tension pulley (45 mm in diameter) are arranged. A V-ribbed belt is hung on each pulley, and the winding angle of the belt around the tension pulley is 90 degrees. Was run at an ambient temperature of 120 ° C. with a rotational speed of 4,900, and the time until the rib rubber cracked was measured. The results are shown in Table 1.

(Belt transmission performance test)
The obtained V-ribbed belt is hung on a drive pulley with a diameter of 80 mm and a driven pulley with a diameter of 110 mm with a load of 5 kgf / rib, and the load is gradually applied to the driven pulley while rotating the drive pulley at 2,000 rpm. The transmission force when the belt slip ratio was 2% was measured. The transmission force at the time of drying and water injection at 120 cc / min was measured, and the reduction rate of the transmission torque was calculated. The results are shown in Table 1.

(Pronunciation test)
The obtained V-ribbed belt is suspended at a predetermined belt tension between a driving pulley having a diameter of 135 mm, a first driven pulley having a diameter of 112 mm, and a second driven pulley having a diameter of 60 mm and having a clutch mechanism. The presence or absence of a squeal generated when the second driven pulley was rotated while rotating at 000 rpm, and the squeak during water injection at 120 cc / min were measured. The results are shown in Table 1.

  In Example 1 where the blending amount of the powder rubber A is 20 parts by mass, the wear resistance is improved as compared with the reference example in which the powder rubber is not blended, and the durability is as good as the reference example. Obtained.

  In Example 2 in which the blending amount of the powder rubber A composed of a crosslinked rubber containing an ethylene-α-olefin elastomer as a main component was 40 parts by mass, the adhesiveness of the rubber sheet was slightly lowered. There was no wear resistance.

  In Example 3 in which the blending amount of the powder rubber B composed of a crosslinked rubber containing chloroprene rubber as a main component was 40 parts by mass, the adhesiveness of the rubber sheet was slightly lowered, but there was no major problem in workability, and the abrasion resistance Wear was improved. In addition, the rate of decrease in transmission torque from dry to wet became small, and no sound was produced even when wet.

  In Comparative Example 1 and Comparative Example 2 in which the blending amount of the powder rubber exceeds 40 parts by mass, Comparative Example 1 has poor rubber sheet adhesiveness and surface condition, and there is a problem in workability. However, the physical properties of the rubber deteriorated significantly, and in the belt durability test, cracks occurred early and the life was shortened.

  In Comparative Example 3 in which the amount of carbon black was increased, the wear resistance was improved, but the hardness increased and the EB decreased greatly, and there was a problem in durability.

  The power transmission belt of the present invention is used in a drive device for automobiles or general industries.

It is a cross-sectional perspective view of the V-ribbed belt which is one Example of the transmission belt of this invention. It is sectional drawing of the low edge V belt which is another Example of the power transmission belt of this invention.

Explanation of symbols

1 V-ribbed belt 2, 23 Core wire 3, 24 Adhesive rubber layer 4, 26 Compression rubber layer 21 Low-edge V-belt

Claims (5)

In a transmission belt comprising an adhesive rubber layer in which a core wire extending in the longitudinal direction of the belt is embedded and a compressed rubber layer adjacent to the adhesive rubber layer, the compressed rubber layer contains a crosslinked rubber with respect to 100 parts by mass of the ethylene-α-olefin elastomer. A power transmission belt comprising a rubber composition in which powdered powder rubber is compounded in an amount of 40 parts by mass or less. The transmission belt according to claim 1, wherein the powder rubber has an average particle size of 10 μm to 500 μm. The crosslinked rubber is composed mainly of at least one selected from ethylene-α-olefin elastomer, chloroprene rubber, natural rubber, styrene butadiene rubber, acrylonitrile butadiene rubber, chlorosulfonated polyethylene rubber, and alkylated chlorosulfonated polyethylene rubber. The transmission belt according to claim 1 or 2. The power transmission belt according to any one of claims 1 to 3, wherein the powder rubber is a waste generated when the power transmission belt is manufactured. The power transmission belt according to any one of claims 1 to 4, wherein the power transmission belt is a V-ribbed belt having a plurality of rib portions extending in the longitudinal direction of the belt in the compressed rubber layer.

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