JP2005240925A - Power transmission belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmission belt, for suppressing occurrence of belt slippage and maintaining the effect after the lapse of time, even if water enters into an engine room in running in the rain. <P>SOLUTION: In a V-ribbed belt 1, a compression rubber layer 4 having ribs is adjacent to an adhesive rubber layer 2 in which core wires are buried along a longitudinal direction of the belt, and a base cloth 5 is laminated on a belt back surface. The compression rubber layer 4 is constituted of rubber composition in which 10-35 pts.wt. of bamboo fiber is blended with respect to 100 pts.wt. of rubber. Since a contact part with a pulley is constituted of the rubber composition, a water film removing effect in filling water is exerted to suppress slippage. Further, effect of suppressing generation of noise in the running is high. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a power transmission belt, and more particularly to a power transmission belt that can exhibit high power transmission even when water adheres to a transmission surface.

  In recent years, there has been a demand for higher performance and higher performance of automotive parts, especially automobile parts. Under such circumstances, there is a demand for a power transmission belt having high transmission performance not only during normal running but also during water injection. In addition, there is a strict requirement for quietness. In particular, in the drive device, since sounds other than the engine sound are abnormal sounds, there is also a request for measures against belt sound generation.

  Abnormal noise in the power transmission belt drive system is generated by slip noise generated under conditions of large rotational fluctuations or high load conditions, or by adhesive rubber adhering to the groove bottom between ribs as a result of adhesive rubber layers. However, these pronunciations can be dealt with by adding short fibers such as cotton, nylon and polyester to the compressed rubber layer, or increasing the amount of reinforcing material such as carbon black. .

However, when water enters the engine room during rainy weather and water adheres between the belt and the pulley, the belt has a low water film removal effect, so the slip rate is high and transmission performance is reduced. There was a problem such as noise. As countermeasures against slipping during such water injection, attempts have been made to apply powder such as talc to the surface of the compressed rubber layer or to increase the belt tension to reduce the slip ratio. There is also a proposal of forming a compressed rubber layer with a rubber composition containing a specific fiber (para-aramid fiber). (See Patent Document 1)
JP 07-151191 A

  However, with respect to powder application, there is a problem that the cost is increased due to an increase in work processes, and the powder on the belt surface is peeled off over time, and the slip suppression effect is reduced. On the other hand, it has been pointed out that when the belt tension is set high initially, the belt tension gradually decreases due to belt wear, core elongation, etc., and slip easily occurs over time. Further, a belt mixed with para-aramid fibers has low water absorption performance, and the water film removal effect cannot be said to be sufficient.

  As a result of intensive research in view of the above problems, the present invention is proposed, and the object is to suppress the occurrence of belt slip even during water injection and to maintain the effect over time. Is to provide a simple transmission belt.

  That is, according to the first aspect of the present invention, in the power transmission belt, in the power transmission belt comprising the core wire embedded along the longitudinal direction of the belt and the elastic body including the compression rubber layer, at least the compression rubber The surface of the layer is composed of a rubber compound containing bamboo fiber.

  The invention according to claim 2 of the present application is the power transmission belt according to claim 1, wherein the rubber compound is blended with 10 to 35 parts by mass of bamboo fiber with respect to 100 parts by mass of rubber. To do.

  The invention according to claim 3 of the present application is the power transmission belt according to claim 1 or 2, wherein the power transmission belt is a V-ribbed belt having at least one rib portion in a compression rubber layer.

  According to the invention described in the claims of the present application, a belt having a high transmission performance at the time of water injection and an improved generation of slip noise is formed by configuring at least the compressed rubber layer side surface with a rubber compound containing bamboo fiber. Could be provided. In addition, by making the blending amount of bamboo fiber a specific amount, higher transmission performance can be obtained at the time of water injection, and the physical properties of the belt are not affected. Moreover, by applying to a V-ribbed belt, high frictional transmission can be obtained even during water injection.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 shows a V-ribbed belt 1 as an example of a power transmission belt according to the present invention. The V-ribbed belt 1 has a core wire 3 made of a fiber cord made of polyester fiber, aramid fiber, glass fiber or the like embedded in an adhesive rubber layer 2 and has a compression rubber layer 4 below it. The compressed rubber layer 4 is provided with a plurality of ribs having a substantially triangular cross section extending in the longitudinal direction of the belt, and a base fabric 5 is laminated on the belt surface.

  In the present embodiment, at least the rib portion surface 9 is made of a rubber composition containing bamboo fiber 6. By forming the surface of the rib part, that is, the contact part with the pulley with the rubber composition, it is difficult to form a water film on the surface of the rib part at the time of water injection, and slip during running can be suppressed. It also has a high effect on reinforcing properties.

  FIG. 1 shows a specific embodiment, in which the entire compressed rubber layer 4 is made of a rubber composition containing bamboo fibers 6. However, at least the rib part surface is made of the rubber. For example, only the surface layer of the compressed rubber layer may be composed of the rubber compound.

  Bamboo fiber is a natural fiber derived from bamboo, has a higher official moisture content (about 12-13%) than cotton, and is characterized by excellent moisture absorption and desorption. The moisture content (%) is a numerical value indicating how much moisture is absorbed with respect to its own weight under the condition of 20 ° C. × 65% RH, and is an index representing the capacity of water absorption performance of the fiber itself. Due to the excellent hygroscopicity of this bamboo fiber, it is difficult for the rubber surface containing the fiber to form a water film, while the high moisture desorption property of the bamboo fiber allows the water absorbed to be released quickly and the hygroscopic performance can be maintained. effective. Bamboo fibers having a fiber diameter of 10 to 30 μm and a fiber length of 1 to 6 mm are preferably used. In addition, the bamboo fiber opened is higher in wettability than the bamboo fiber in the fiber bundle, and the water film removing effect is higher.

  The blending ratio of bamboo fiber 6 in the rubber compound is preferably 10 to 35 parts by mass with respect to 100 parts by mass of rubber. When the amount is less than 10 parts by mass, there is a problem that the anti-slip effect at the time of water injection cannot be sufficiently obtained. On the other hand, when it exceeds 35 parts by mass, workability such as poor dispersion is difficult, and the rigidity of the rubber compound is low. Due to the increase, there is a problem in belt properties such as flexibility.

  As the polymer used for the compressed rubber layer 4, hydrogenated nitrile rubber, chloroprene rubber, natural rubber, CSM, ACSM, SBR, and ethylene-α-olefin elastomer are used. Hydrogenated nitrile rubber has a hydrogenation rate of 80% or more. In order to exhibit heat resistance and ozone resistance, 90% or more is preferable. Hydrogenated nitrile rubber having a hydrogenation rate of less than 80% has extremely low heat resistance and ozone resistance. Considering oil resistance and cold resistance, the amount of bound acrylonitrile is preferably in the range of 20 to 45%. Among these, an ethylene-α-olefin elastomer having oil resistance and cold resistance is preferable.

  A typical example of the ethylene-α-olefin elastomer is EPDM, which refers to an ethylene-propylene-diene monomer. Examples of diene monomers include dicyclopentadiene, methylene norbornene, ethylidene norbornene, 1,4-hexadiene, cyclooctadiene, and the like.

  For crosslinking the rubber, sulfur or organic peroxide is used. Specific examples of the organic peroxide include di-t-butyl peroxide, dicumyl peroxide, t-butylcumyl peroxide, 1.1-t-butylperoxy-3.3.5-trimethylcyclohexane, and 2. 5-di-methyl-2.5-di (t-butylperoxy) hexane, 2.5-di-methyl-2.5-di (t-butylperoxy) hexane-3, bis (t-butylperoxydi-isopropyl) benzene, Examples include 2.5-di-methyl-2.5-di (benzoylperoxy) hexane, t-butylperoxybenzoate, and t-butylperoxy-2-ethyl-hexyl carbonate. This organic peroxide is usually used alone or as a mixture in the range of 0.005 to 0.02 mol g with respect to 100 g of the ethylene-α-olefin elastomer.

  A vulcanization accelerator may be blended. Examples of vulcanization accelerators include thiazole, thiuram, and sulfenamide vulcanization accelerators. Specific examples of thiazole vulcanization accelerators include 2-mercaptobenzothiazole, 2-mercaptothiazoline, dibendiazyl, Disulfide, zinc salt of 2-mercaptobenzothiazole, and the like, and thiuram vulcanization accelerators include tetramethylthiuram monosulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, N, N'-dimethyl. -N, N'-diphenylthiuram disulfide and the like, and specific examples of sulfenamide vulcanization accelerators include N-cyclohexyl-2-benzothiazylsulfenamide, N, N'-cyclohexyl-2 -Benzothiazylsulfenamide and the like. As other vulcanization accelerators, bismaleimide, ethylenethiourea, and the like can be used. These vulcanization accelerators may be used alone or in combination of two or more.

  Further, by adding a co-agent, it is possible to increase the degree of cross-linking and prevent problems such as adhesive wear. Examples of the crosslinking aid include TIAC, TAC, 1,2 polybutadiene, metal salt of unsaturated carboxylic acid, oximes, guanidine, trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate, NN′-m- Usually used for peroxide crosslinking such as phenylene bismaleimide and sulfur.

  And other than that, usual rubber compounds such as reinforcing agents such as silica and carbon black, fillers such as calcium carbonate and talc, plasticizers, anti-aging agents, processing aids and coloring agents. What is used for is used.

  Further, short fibers other than the bamboo fibers 6 such as nylon 6, nylon 66, polyester, cotton, and aramid are mixed in the compressed rubber layer 4 to improve the side pressure resistance of the compressed rubber layer 4. Can do. In addition, the short fibers can be projected from the surface of the compressed rubber layer 4 which is in contact with the pulleys, and the friction coefficient of the compressed rubber layer 4 can be reduced to reduce noise during belt running. Of these short fibers, aramid short fibers that are rigid, strong, and wear resistant are most effective.

  In order for the aramid short fibers to sufficiently exhibit the above-described effects, the fiber length of the aramid fibers is 1.5 to 20 mm, and the addition amount is 1 to 30 with respect to 100 parts by weight of the ethylene-α-olefin elastomer. Parts by weight. This aramid fiber is an aramid having an aromatic ring in its molecular structure, for example, trade name Conex, Nomex, Kevlar, Technora, Twaron, etc.

  If the amount of aramid short fibers added is less than 1 part by weight, the rubber of the compressed rubber layer 4 tends to stick and wear, and if it exceeds 30 parts by weight, the short fibers are uniformly distributed in the rubber. Disperse. However, the addition of this aramid short fiber is not essential, and a short fiber made of another material may be added. Moreover, it is not restricted to adding alone.

  The base fabric 5 is a canvas selected from a woven fabric, a knitted fabric, and a non-woven fabric. Known and publicly used fiber materials can be used. For example, natural fibers such as cotton and hemp, inorganic fibers such as metal fibers and glass fibers, and polyamide, polyester, polyethylene, polyurethane, polystyrene, and polyfluoroethylene. , Organic fibers such as polyacryl, polyvinyl alcohol, wholly aromatic polyester, and aramid.

  The base cloth 5 is immersed in a resorcin-formalin-latex liquid (RFL liquid) according to a known technique, and then friction is applied by rubbing unvulcanized rubber into the base cloth 5, or the rubber is dissolved in a solvent after being immersed in the RFL liquid. Soak in a soaking solution. The RFL solution may be appropriately mixed with a carbon black solution to blacken the treatment, or a known surfactant may be added in an amount of 0.1 to 5.0% by mass.

  As the core 3, polyester fiber, aramid fiber, glass fiber, or the like is used, and the total denier number obtained by twisting together polyester fiber filament groups mainly composed of ethylene-2,6-naphthalate is 4,000-8. A cord subjected to adhesion treatment of 1,000 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 wire 3 is subjected to an adhesion treatment for the purpose of improving the adhesion to rubber. As such an adhesion treatment, it is common to immerse the fiber in a resorcin-formalin-latex (RFL) solution and then heat-dry to form a uniform adhesion layer on the surface. However, the present invention is not limited to this, and there is also 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.

  On the other hand, the adhesive rubber layer 2 has heat resistance and the same kind of rubber as the compressed rubber layer 4 is used. However, short fibers are not mixed in, but as usual, reinforcing agents such as carbon black and silica, fillers such as calcium carbonate and talc, plasticizers, anti-aging agents, processing aids, colorants, etc. What is used for rubber compounding is 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.

  The V-ribbed belt 1 is an embodiment of the present invention and is not limited to this. For example, a V-belt 10 is shown in FIG. 2 as another example of the power transmission belt according to the present invention. The V-belt 10 has a core wire 13 embedded in the adhesive rubber layer 12 along the longitudinal direction of the belt, and has an extension rubber layer 20 and a compression rubber layer 14 adjacent to the upper and lower portions of the adhesive rubber layer 12. The layer 20 has a structure in which the base fabric 15 is laminated on the surface thereof. At least the compressed rubber layer surface 19 is composed of a rubber composition containing bamboo fiber 6. If necessary, the compressed rubber layer 12 may be provided with cogs at predetermined intervals in the belt longitudinal direction.

Hereinafter, the present invention will be described in more detail with reference to examples.
Examples 1-4, Comparative Examples 1-4
A chloroprene rubber sheet (compressed rubber layer) having the composition shown in Table 1 and a chloroprene rubber sheet (adhesive rubber layer) having a composition excluding fibers from Table 1 were prepared. After winding 1 ply of a canvas with rubber coated with chloroprene rubber on a plain fabric made of cotton yarn of warp and weft, a cylindrical mold is wrapped with a chloroprene rubber sheet (adhesive rubber layer), and then a cord is spun onto it. Then, a chloroprene rubber sheet (compressed rubber layer) was wound to finish the molding. This was vulcanized at 160 ° C. for 30 minutes by a known method to obtain a cylindrical vulcanized rubber sleeve.

  Each of the vulcanized rubber sleeves was mounted on a driving roll and a driven roll of a polishing machine and rotated after imparting tension. A polishing wheel equipped with 150 mesh diamond on its surface was rotated at 1,600 rpm, and this was brought into contact with the vulcanization sleeve to polish the rib portion. The sleeve taken out from the polishing machine was placed in a cutting machine and then cut while rotating.

  In the manufactured V-ribbed belt, the core wire is embedded in the adhesive rubber layer, one ply of cotton canvas with rubber is laminated on the upper side, and the rubber compression part is provided on the lower side of the adhesive rubber layer, and a plurality of ribs are provided. It is provided in the belt longitudinal direction. This V-ribbed belt was a K-type 3PK1100 having a length of 1,100 mm according to the RMA standard.

  Each of these manufactured V-ribbed belts was tested for belt transmission performance during water injection and dry running. The above-mentioned V-ribbed belt is wound around a driving pulley (diameter 120 mm) and a driven pulley (diameter 120 mm) to adjust the belt tension to a constant (10.2 kgf / belt), the ambient temperature is 23 ° C., the rotational speed of the driving pulley is 2,000 rpm, water injection While increasing the load under the condition of (water injection amount 120 ml / min), the load when the belt slip rate was 2% was determined. Moreover, in the evaluation at the time of dryness, the test was performed without performing water injection with the same layout.

  In addition, as a sound production performance test, the sound production limit tension of each belt was tested. The V-ribbed belt is wound around a drive pulley (diameter 120 mm) and a driven pulley (diameter 120 mm), and the load is kept constant at 0.92 kgf · m. The belt tension at the time of sounding was defined as the sounding limit tension. These results are also shown in Table 1.

  As a result, it can be seen that the example composed of the rubber composition containing bamboo fiber has improved transmission performance during water injection compared to the comparative example. In particular, Examples 2 and 3 containing an appropriate amount of bamboo fiber were found to have a low sounding limit tension and an excellent noise reduction effect. In addition, there is an effect that a difference in slip rate between dry and water injection is small. However, in Example 1 in which a small amount of bamboo fiber is blended, the transmission performance during water injection is higher than that in Comparative Example 1, but the sound generation suppression effect is not significant. Further, in Example 4 in which a large amount of bamboo fiber was blended, although the transmission performance at the time of water injection was good, there was a problem that the rigidity of the rubber composition was high and the processability was poor. In Comparative Examples 1 to 4, cotton short fibers, which are generally said to have a high moisture content, are blended. However, it was found that the transmission performance during water injection and the pronunciation suppression effect are lower than in the blended examples. .

It is a section perspective view of the V ribbed belt concerning the present invention. It is a section perspective view of the V belt concerning the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 V ribbed belt 2 Adhesive rubber layer 3 Core wire 4 Compression rubber layer 5 Base cloth 6 Bamboo fiber 9 Rib surface 10 V belt 12 Adhesive rubber layer 13 Core wire 14 Compression rubber layer 15 Base cloth 19 Compression rubber layer surface 20 Stretch rubber layer

Claims (3)

  In a power transmission belt composed of a core wire embedded along the belt longitudinal direction and an elastic body including a compressed rubber layer, at least the surface of the compressed rubber layer is made of a rubber compound containing bamboo fiber. Power transmission belt characterized by   The power transmission belt according to claim 1, wherein the rubber compound contains 10 to 35 parts by mass of bamboo fiber based on 100 parts by mass of rubber. The power transmission belt according to claim 1 or 2, wherein the power transmission belt is a V-ribbed belt having at least one rib portion in a compressed rubber layer.

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