JP6532454B2 - Friction transmission belt - Google Patents

Description

  The present disclosure relates to a friction transmission belt.

  V-ribbed belts are widely and generally used as friction transmission belts and the like for transmitting the power of engines mounted on automobiles for accessory driving. When rainwater or the like at the time of rain adheres to such a V-ribbed belt, a belt slip or the like becomes large and abnormal noise occurs.

  On the other hand, it is proposed in patent document 1 to suppress the fall of the transmission capability at the time of water immersion, and generation | occurrence | production of noise by forming a friction transmission belt with a porous rubber composition.

JP 2007-255635 A

  However, with respect to the performance required for the friction transmission belt, the rubber bubble rate disclosed in Patent Document 1 is insufficient to suppress abnormal noise, and the strength of the belt is lowered, so that the bubble rate is further increased. There is a problem that it can not be enhanced.

  In view of this, an object of the technology of the present disclosure is to provide a friction transmission belt capable of further suppressing abnormal noise when water is flooded.

  In order to achieve the above object, the friction transmission belt of the present disclosure is a friction transmission belt including a pulley contact portion formed of a rubber composition in a belt body, and a plurality of pulley contact surfaces on the pulley contact portion. A recess is formed, and the opening of the recess in the pulley contact surface has a long shape on one side, and the average aspect ratio of the shape is 1.2 or more and 10 or less.

  According to such a friction transmission belt, even when the belt is covered with water, it is easily drained by the recess, and noise can be suppressed. In particular, even if the area of the opening of the recess is the same, the effect of suppressing drainage and abnormal noise is high by forming the recess having the above aspect ratio.

  In the pulley contact surface, when the sliding direction of the friction transmission belt is an angle of 0 °, the average of the angles in the longitudinal direction of the opening may be in the range of −45 ° to + 45 °.

  In such a case, abnormal noise at the time of water immersion can be suppressed more reliably.

  In the pulley contact surface, the dimension in the direction perpendicular to the longitudinal direction of the opening may be 200 μm or less.

  If the dimension exceeds 200 μm, the durability of the belt is reduced. Therefore, it is preferable to avoid this and to set it to 200 μm or less.

  As described above, according to the friction transmission belt of the present disclosure, it is possible to suppress abnormal noise at the time of water coverage by providing the long concave portion on one side of the pulley contact surface.

FIG. 1 is a perspective view of a V-ribbed belt according to an embodiment of the present disclosure. FIGS. 2 (a) and 2 (b) are diagrams showing recesses formed in the pulley contact surface in the V-ribbed belt of FIG. FIG. 3 is a pulley layout diagram of the accessory drive belt transmission. FIGS. 4A and 4B are explanatory views showing a method of manufacturing a V-ribbed belt. FIG. 5 is a view showing a pulley layout of a belt traveling test apparatus for evaluating the durability of the belt.

  Hereinafter, embodiments will be described based on the drawings.

  FIG. 1 shows a V-ribbed belt B (friction transmission belt) according to an embodiment of the present disclosure. The V-ribbed belt B according to this embodiment is used, for example, in an accessory drive belt transmission provided in an engine room of a car. The V-ribbed belt B according to the present embodiment has, for example, a belt circumferential length of 700 to 3000 mm, a belt width of 10 to 36 mm, and a belt thickness of 3.5 to 5.0 mm.

  The V-ribbed belt B according to the present embodiment includes the V-ribbed belt main body 10 configured as a triple layer of the compression rubber layer 11 on the inner circumferential side of the belt, the adhesive rubber layer 12 in the middle, and the rear rubber layer 13 on the outer circumferential side of the belt. In the adhesive rubber layer 12, core wires 14 disposed to form a spiral having a pitch in the belt width direction are embedded.

  The compression rubber layer 11 is provided such that a plurality of V-ribs 15 hang down on the inner circumferential side of the belt. The plurality of V-ribs 15 are each formed in a protrusion having a substantially inverted triangle cross section extending in the belt length direction, and are arranged in parallel in the belt width direction. Each V rib 15 has, for example, a rib height of 1.5 to 3.0 mm and a width between proximal ends of 1.0 to 3.6 mm. The number of ribs is, for example, 3 to 6 (in FIG. 1, the number of ribs is 6). The compressed rubber layer 11 is formed of a rubber composition obtained by heating and pressurizing an uncrosslinked rubber composition in which various compounding agents are compounded into the rubber component and kneaded, and crosslinking is performed by the crosslinking agent.

  Further, a large number of recesses 16 are formed on the surface of the compression rubber layer 11. This is shown in FIGS. 2 (a) and 2 (b).

  FIG. 2A shows the surface (pulley contact surface) of the compressed rubber layer 11 of the V-ribbed belt B, and shows a small number of concave portions 16 formed therein. The recess 16 has an opening with a long shape on one side in the pulley contact surface, and the average of the aspect ratio of the shape is 1.2 or more and 10 or less. The aspect ratio is further illustrated in FIG. 2 (b). FIG. 2 (b) shows the shape of the opening on the pulley contact surface of one recess 16, and the longitudinal direction is the dimension a, and the short direction (direction orthogonal to the longitudinal direction) is the dimension b. It is shown that. At this time, the aspect ratio is a / b.

  Further, when the sliding direction 17 of the V-ribbed belt B is 0 °, the longitudinal direction of the recess 16 is in the range of −45 ° to + 45 ° on average.

  In addition, the recessed part 16 is formed by mix | blending what gathered the hollow particle by the binder with the rubber composition which comprises the compression rubber layer 11, for example.

  The hollow particles may be of the expanding type. For example, it is a thermally expandable pellet in which a low boiling point hydrocarbon is contained in a thermoplastic polymer cell such as ADVANCEL EM 403 manufactured by Sekisui Chemical Co., Ltd. The low-boiling hydrocarbon contained by heating expands due to heating, and at the same time the thermoplastic shell softens and expands rapidly and becomes hollow. In addition, for example, those of 092-40 and 092-120 acrylonitrile copolymers manufactured by Nippon Fillite Co., Ltd., EHM 303 and EMS-022 manufactured by Sekisui Chemical Co., Ltd., and Washin microcapsules manufactured by Washin Chemical Industry Co., Ltd. It can be mentioned.

  The hollow particles preferably have a particle size of, for example, 100 μm or less. Moreover, it is preferable that the compounding quantity with respect to 100 mass parts of base elastomers of a hollow particle is 1 mass part or more and 15 mass parts or less.

  Also, the hollow particles may be of a non-expanding type. For example, thermal expansion microcapsules 920 DE 80 d 30 or the like manufactured by Nippon Fillite Co., Ltd. can be used. In this case, the initial particle size is preferably 40 μm to 120 μm, more preferably 80 μm to 100 μm.

  Further, hollow particles of an expanding type may be used in combination with a chemical foaming agent such as, for example, Celmic CE manufactured by Sankyo Kasei Co., Ltd.

  The rubber component of the rubber composition forming the compression rubber layer 11 is, for example, ethylene-α-olefin elastomer, chloroprene rubber (CR), chlorosulfonated polyethylene rubber (CSM), hydrogenated acrylonitrile rubber (H-NBR), etc. It can be mentioned. The rubber component may be composed of a single species, or may be composed of a blend of a plurality of species.

  As the compounding agent, reinforcing materials such as carbon black, a vulcanization accelerator, a crosslinking agent, an antiaging agent, a softener and the like can be mentioned.

  As a reinforcing material, for carbon black, for example, channel black; furnace black such as SAF, ISAF, N-339, HAF, N-351, MAF, FEF, SRF, GPF, ECF, N-234, etc .; FT, MT, etc. Thermal black; and acetylene black. The reinforcing agent also includes silica. The reinforcing agent may be composed of a single type, or may be composed of a plurality of types. The amount of the reinforcing material is preferably 30 to 80 parts by mass with respect to 100 parts by mass of the rubber component from the viewpoint that the balance between the abrasion resistance and the bending resistance is good.

  Examples of the vulcanization accelerator include metal oxides such as magnesium oxide and zinc oxide (zinc white), metal carbonates, fatty acids such as stearic acid, and derivatives thereof. The vulcanization accelerator may be composed of a single species or may be composed of a plurality of species. The compounding amount is, for example, 0.5 to 8 parts by mass with respect to 100 parts by mass of the rubber component.

  Examples of crosslinking agents include sulfur and organic peroxides. As a crosslinking agent, one using sulfur, one using an organic peroxide, or one using both of them in combination may be used. In the case of sulfur, the crosslinking agent is preferably used in an amount of 0.5 to 4.0 parts by mass with respect to 100 parts by mass of the rubber component, and in the case of an organic peroxide, the compounding amount per 100 parts by mass of the rubber component is, for example, 0 0.5 to 8 parts by mass.

  Examples of the antiaging agent include amines, quinolines, hydroquinone derivatives, phenols and phosphites. The antiaging agent may be composed of a single species, or may be composed of a plurality of species. The blending amount of the antioxidant is, for example, 0 to 8 parts by mass with respect to 100 parts by mass of the rubber component.

  Examples of softeners include petroleum softeners, mineral oil softeners such as paraffin wax, castor oil, cottonseed oil, linseed oil, rapeseed oil, rapeseed oil, soybean oil, palm oil, coconut oil, falling green oil, wax, rosin, rosin And vegetable oil-based softeners such as pine oil. The softener may be composed of a single species or may be composed of a plurality of species. The amount of the softener other than the petroleum-based softener is, for example, 2 to 30 parts by mass with respect to 100 parts by mass of the rubber component.

  In addition, layered silicates such as smectite group, vermiculite group and kaolin group may be contained as a compounding agent.

  Moreover, it is also possible to make the compression rubber layer 11 contain a friction coefficient reducing material. Examples of the friction coefficient reducing material include nylon short fibers, vinylon short fibers, aramid short fibers, polyester short fibers, short fibers such as cotton short fibers, and ultrahigh molecular weight polyethylene resins.

  Next, the adhesive rubber layer 12 is formed in a strip shape having a rectangular cross section, and has a thickness of, for example, 1.0 to 2.5 mm. The back rubber layer 13 is also formed in a strip shape having a rectangular cross section, and has a thickness of, for example, 0.4 to 0.8 mm. The surface of the back rubber layer 13 is preferably formed in a form to which the texture of the woven fabric is transferred from the viewpoint of suppressing the sound generated between the belt and the flat pulley with which the back surface contacts. The adhesive rubber layer 12 and the back rubber layer 13 are formed of a rubber composition obtained by heating and pressing an uncrosslinked rubber composition in which various compounding agents are mixed and kneaded with a rubber component and heated and pressurized by a crosslinking agent. . The rear rubber layer 13 is preferably formed of a rubber composition slightly harder than the adhesive rubber layer 12 from the viewpoint of suppressing adhesion due to contact with a flat pulley with which the rear surface of the belt contacts. A woven fabric comprising the V-ribbed belt main body 10 composed of the compression rubber layer 11 and the adhesive rubber layer 12 and, instead of the back rubber layer 13, formed of yarns such as cotton, polyamide fiber, polyester fiber, aramid fiber, etc. The structure provided with the reinforcement cloth comprised with the knitted fabric, the nonwoven fabric, etc. may be sufficient.

As a rubber component of the rubber composition which forms adhesion rubber layer 12 and back rubber layer 13, for example, ethylene-α-olefin elastomer, chloroprene rubber (CR), chlorosulfonated polyethylene rubber (CSM), hydrogenated acrylonitrile rubber ( H-NBR) etc. are mentioned. The rubber components of the adhesive rubber layer 12 and the back rubber layer 13 are preferably the same as the rubber components of the compression rubber layer 11.

  As the compounding agent, similar to the compressed rubber layer 11, for example, a reinforcing material such as carbon black, a vulcanization accelerator, a crosslinking agent, an antiaging agent, a softener and the like can be mentioned.

  The compression rubber layer 11, the adhesive rubber layer 12, and the back rubber layer 13 may be formed of rubber compositions of different formulations, or may be formed of rubber compositions of the same formulation.

  Moreover, the core wire 14 is comprised with yarns, such as a polyester fiber (PET), a polyethylene naphthalate fiber (PEN), an aramid fiber, a vinylon fiber. In order to impart adhesiveness to the V-ribbed belt main body 10, the core wire 14 is subjected to an adhesion treatment in which it is immersed in an RFL aqueous solution and then heated before being molded and / or an adhesion treatment in which it is dried after being immersed in rubber paste. .

  Next, FIG. 3 shows a pulley layout of the accessory drive belt transmission 20 of the automobile using the V-ribbed belt B according to the present embodiment. The accessory drive belt transmission 20 is a serpentine drive type in which a V-ribbed belt B is wound around a total of four rib pulleys and two flat pulleys and six pulleys to transmit power.

  The accessory drive belt transmission 20 includes the power steering pulley 21 at the uppermost position in FIG. 3, an AC generator pulley 22 disposed slightly diagonally to the right of the power steering pulley 21, and a diagonally lower left of the power steering pulley 21. A flat pulley tensioner pulley 23 disposed obliquely above the left of the AC generator pulley 22, a water pump pulley 24 of the flat pulley disposed obliquely below the AC generator pulley 22 and directly below the tensioner pulley 23, a tensioner The pulley 23 and the water pump pulley 24 are provided with a crankshaft pulley 25 disposed obliquely downward to the left, and an air conditioner pulley 26 disposed obliquely downward and left to the water pump pulley 24 and the crankshaft pulley 25. Among these, all except the tensioner pulley 23 which is a flat pulley and the water pump pulley 24 are rib pulleys. These rib pulleys and flat pulleys are made of, for example, a pressed product of metal or a cast product, or a resin molded product such as nylon resin or phenol resin, and the pulley diameter is 50 to 150 mm.

  In this accessory drive belt transmission device 20, the V-ribbed belt B is wound around the power steering pulley 21 so that the V rib 15 side contacts, and then wound around the tensioner pulley 23 so that the belt back surface contacts. , And the V rib 15 side is sequentially wound around the crankshaft pulley 25 and the air conditioner pulley 26 and is further wound around the water pump pulley 24 so that the belt back surface is in contact, and the V rib 15 side is in contact Is wound around the AC generator pulley 22 and finally returned to the power steering pulley 21.

  According to the V-ribbed belt B of the present embodiment, a large number of recesses 16 are formed on the surface of the V-rib 15 which is a pulley contact surface, whereby, for example, as described above, the accessory transmission belt drive of an automobile Even when water is used for water, generation of abnormal noise can be suppressed. This is because the water present between the belt and the pulley is drained to the outside after being taken into the recess 16 and is quickly removed.

  Furthermore, the average of the aspect ratio of the recesses is 1.2 or more and 10 or less, and the average of the recesses in the longitudinal direction is in the range of -45 ° to + 45 ° when the friction transmission direction of V-ribbed belt B is 0 °. . As a result, the drainage property can be improved without increasing the air bubble rate in the compression rubber layer 11, and the friction during the water immersion can be more reliably suppressed without causing the deterioration of the durability of the belt and the like. A power transmission belt can be realized. Moreover, since it is not necessary to increase the compounding amount of the hollow particles, the design of the rubber matrix portion for obtaining the desired performance with respect to the elastic modulus, the abrasion resistance and the like becomes easy.

  As a reason for this, it is considered that the capillary phenomenon is remarkably exhibited by the shape having a large aspect ratio. Further, when the longitudinal direction of the recess is made close to the sliding direction, water can be drained in the longitudinal direction of the recess along with the sliding of the belt, and the efficiency of drainage can be improved. As a result, suppression of abnormal noise becomes remarkable.

  Next, a method of manufacturing the V-ribbed belt B will be described based on FIGS. 4 (a) and 4 (b).

  In manufacturing the V-ribbed belt B, an inner mold having a molding surface for forming the back surface of the belt in a predetermined shape on the outer periphery, and a rubber sleeve having a molding surface for forming the inner side of the belt in the predetermined shape on the inner periphery are used.

  First, after covering the outer periphery of the inner mold with a rubber layer 13 'to be the back rubber layer 13, an uncrosslinked rubber sheet 12b' for forming the outer portion 12b of the adhesive rubber layer 12 is wound thereon.

  Then, after twisting 14 'which becomes core wire 14 helically, non-crosslinked rubber sheet 12a' for forming inner part 12a of adhesion rubber layer 12 is wound on it, and also that An uncrosslinked rubber sheet 11 'for forming the compressed rubber layer 11 is wound thereon. At this time, as the non-crosslinked rubber sheet 11 ′ for forming the compressed rubber layer 11, one in which hollow particles are blended is used. The uncrosslinked rubber sheet 11 'is preferably one in which 1 to 15 parts by mass of an aggregate of hollow particles aggregated by a binder is blended with 100 parts by mass of the base elastomer, and 5 to 10 parts It is more preferable that it is partially blended.

  After that, the rubber sleeve is fitted on the molded body on the inner mold and set in the molding pot, and the inner mold is heated by high-heat water vapor and the like, and high pressure is applied to radially inward the rubber sleeve. Press to. At this time, as the rubber component flows, the crosslinking reaction proceeds, and the adhesion reaction of the twisted yarn 14 'to the rubber also proceeds. Further, the hollow particles are expanded by volatilizing pentane, hexane or the like in the particles to form a large number of minute hollow portions inside. And a cylindrical belt slab (belt main body precursor) is shape | molded by this.

  Here, an aggregate of hollow particles is formed as a hollow particle aggregate master batch by pelletizing the hollow particles after adding a binder and kneading. In pelletizing, the size and aspect ratio of the masterbatch can be set, which in turn can set the size and aspect ratio of the recess 16. For example, by forming a hollow particle aggregate in which hollow particles are arranged long in one direction by using a binder, it is possible to make the concave portion 16 also have a long shape on one side. In addition, with respect to the non-crosslinked rubber sheet 11 ', the direction of the hollow particle aggregate can be adjusted by calendering, extrusion molding, or the like. By these, the size, shape, directionality (longitudinal direction), etc. of the recess can be controlled.

  The hollow particles which do not swell at the processing temperature from kneading to molding and the binder which does not melt at this temperature are used and vulcanization is carried out at a temperature higher than the foaming temperature of the hollow particles and the melting temperature of the binder. As a result, the hollow particles are foamed from the aggregate state, whereby a cavity is formed inside the formed compressed rubber layer 11. Among such cavities, those exposed to the pulley contact surface form a recess 16.

  Further, it is desirable that the binder and the base elastomer of the non-crosslinked rubber sheet 11 'be a combination of good compatibility. For example, a combination of polyethylene binder and EPDM, a combination of acrylonitrile binder and NBR, or the like.

  Incidentally, even when only hollow particles are mixed with rubber without using a binder to form a hollow particle aggregate, not all recesses may be formed from a single hollow particle, and hollow particles are aggregated. It is possible to form a recess. However, when a binder is not used, it is difficult to control the number of hollow particles contained in each hollow particle assembly, the aspect ratio of the assembly, etc., and it is also difficult to control the size and shape of the recess. .

  Next, the belt slab is removed from the inner mold and divided into several pieces in the length direction, and then the outer periphery is polished and cut to form the V-ribs 15, that is, the pulley contact portion. At this time, a recess 16 is formed on the pulley contact surface by the collection of hollow particles exposed to the pulley contact surface.

  Finally, the belt slab divided and having the V-ribs 15 formed on the outer periphery is cut to a predetermined width, and the V-ribbed belt B is obtained by turning over the respective front and back.

  Further, instead of forming the V-ribs 15 by cutting, a cylindrical mold having a molding surface provided with a plurality of rib grooves for forming the inside of the belt in a rib shape on the inner periphery may be used.

  In this case, the belt material (rubber layer 13 ', non-crosslinked rubber sheet 12b', twisted yarn 14 ') is provided on the outer periphery of the rubber sleeve having a molding surface for forming the belt back surface in a predetermined shape on the outer periphery. , Uncrosslinked rubber sheet 12a 'and uncrosslinked rubber sheet 11') are sequentially wound.

  After this, the rubber sleeve around which the belt material is wound is inserted and set in the cylindrical mold, and the rubber sleeve inside the cylindrical mold is heated and the rubber sleeve is expanded by water vapor etc. Press towards you. At this time, as the base rubber flows, the crosslinking reaction proceeds and the adhesion reaction of the twisted yarn 14 'to the rubber also proceeds, and additionally, due to the rib shape of the inner periphery of the cylindrical mold, V in the outer peripheral portion of the belt material Ribs 15 are formed. Thus, a cylindrical belt slab (belt main body precursor) is formed. After cooling the forming kettle, the rubber sleeve is removed from the cylindrical mold and the belt slab is removed.

  Finally, the belt slab divided and having the V-ribs 15 formed on the outer periphery is cut to a predetermined width, and the V-ribbed belt B is obtained by turning over the respective front and back.

  Although the V-ribbed belt B is shown as the friction transmission belt in the above description, it is not particularly limited to this, and a low edge type V-belt or the like may be used.

  In addition, although the accessory drive belt transmission 20 of the automobile is shown as the belt transmission, the invention is not particularly limited thereto, and a belt transmission for general industrial use may be used.

  Hereinafter, the V-ribbed belt of the embodiment will be described.

(Test evaluation belt)
V-ribbed belts of Examples 1 to 6 and Comparative Examples 1 to 6 shown in Table 1 were produced.

Example 1
100 parts by mass of ethylene propylene diene monomer (EPDM) (manufactured by JSR Corporation, trade name: EP22) as a base elastomer, 50 parts by mass of carbon black (trade name: Seast 3 manufactured by Tokai Carbon Co., Ltd.) Made by Petroleum Co., Ltd., trade name: Samper 2280) 15 parts by mass, stearic acid (manufactured by Kao Corp., trade name: Lucac) 1 part by mass, zinc oxide (manufactured by Sakai Chemical Industry Co., Ltd., trade name: Zinc flower 3 types) 5 parts by mass Sulfur (Hosoi Chemical Co., Ltd., trade name: oil sulfur) 1.5 parts by mass, vulcanization accelerator (Ouchi New Chemical Co., Ltd., trade name: MSA) 1 part by mass, vulcanization accelerator (Shinshin Chemical Industry Co., Ltd. Made by Co., Ltd., trade name: EM2 3 parts by mass, hollow particles (made by Sekisui Chemical Co., Ltd., trade name: ADVANCEL EM 403), 1.5 parts by mass, binder Click N) to form a V-ribbed belt forming the ribbed rubber layer using by blending 0.2 part by weight uncrosslinked elastomer composition by kneading, which was used as in Example A.

  The adhesive rubber layer and the back rubber layer are respectively composed of the elastomer composition of EPDM, and the core wire is composed of twisted yarn made of polyethylene naphthalate fiber (PEN), the length of the belt is 2280 mm, the width is 25 mm and the thickness is 4. It was 3 mm, and the number of ribs was six.

  The hollow particles and the binder are previously blended to form a hollow particle aggregate master batch. Also, two-stage kneading is performed as kneading of the elastomer, and the hollow particle aggregate masterbatch is added in the second stage. The maximum processing temperature (about 115 ° C.) in the steps from the second stage of kneading to molding is lower than the foaming temperature of hollow particles (about 145 ° C.) and the melting temperature of the binder (about 125 ° C.) The hollow particles are present as unfoamed aggregates. Vulcanization is performed at a temperature (about 145 ° C. to 180 ° C.) higher than the foaming temperature of the hollow particles and the melting temperature of the binder, at which time the hollow particles foam to form recesses in the pulley contact surface.

  In addition, the concave portions are aligned in the sheet row direction by the calendar processing. Therefore, by setting the direction in which the belt is cut out, the longitudinal direction of the recess with respect to the sliding direction of the belt can be set. In Example 1, the cutting was performed so that the sheet alignment direction was the sliding direction of the belt. In the following, assuming that the sliding direction of the belt is 0 °, the angle to this represents the average of the longitudinal direction of the recess.

Example 2
The V-ribbed belt of Example 1 was prepared in the same manner as Example 1 except for the hollow particle assembly.

  Specifically, in Example 2, a hollow particle aggregate masterbatch having a larger aspect ratio than that of Example 1 was used. This is obtained by kneading the binder and the hollow particles, extruding them in a linear manner, and cutting (pelletizing) them into a longer shape than in Example 1.

Example 3
The V-ribbed belt of Example 3 was prepared in the same manner as the V-ribbed belt of Example 1 except that the belt was cut out so that the sheet orientation direction was oblique to the sliding direction of the belt.

Example 4
The V-ribbed belt of Example 4 was prepared in the same manner as the V-ribbed belt of Example 1.

Example 5
The V-ribbed belt of Example 5 is an example except that the belt is cut out so that the sheet alignment direction is oblique to the sliding direction of the belt (opposite to the case of Example 3). It was prepared in the same manner as the V-ribbed belt of 1.

Example 6
The V-ribbed belt of Example 6 was prepared in the same manner as the V-ribbed belt of Example 1.

Comparative Example 1
The V-ribbed belt of Comparative Example 1 was prepared in the same manner as the V-ribbed belt of Example 1 except that the hollow particle assembly was not blended.

Comparative Example 2
The V-ribbed belt of Comparative Example 2 was prepared in the same manner as the V-ribbed belt of Example 1 except that a hollow particle aggregate masterbatch having a smaller aspect ratio than that of Example 1 was used.

Comparative Example 3
The V-ribbed belt of Comparative Example 3 was prepared in the same manner as the V-ribbed belt of Example 1 except that a hollow particle aggregate masterbatch having a larger aspect ratio than that of Example 2 was used.

Comparative Example 4
The V-ribbed belt of Comparative Example 4 is the V of Example 3 except that the belt is cut out so that the sheet orientation direction is more oblique to the sliding direction of the belt than in the case of Example 3. Made like a ribbed belt.

Comparative Example 5
The V-ribbed belt of Comparative Example 5 was prepared in the same manner as the V-ribbed belt of Example 3 except that the belt was cut out with the intention that the sheet alignment direction was perpendicular to the sliding direction of the belt. .

Comparative Example 6
The V-ribbed belt of Comparative Example 6 is the V of Example 3 except that the belt is cut out so that the sheet orientation direction is more oblique to the belt sliding direction than in the case of Example 5. Made like a ribbed belt.

Comparative Example 7
The V-ribbed belt of Comparative Example 7 was prepared in the same manner as the V-ribbed belt of Example 1, except that a hollow particle aggregate masterbatch having a larger size than that of Example 1 was used.

<Evaluation of pronunciation>
The V-ribbed belts of Examples 1 to 6 and Comparative Examples 1 to 7 are attached to an accessory drive belt drive of an automobile engine having a large rotation fluctuation and a large load, and 120 ml / min to the V-ribbed belt in an idling state. An amount of water was dropped, and the sound pressure at that time was measured. Then, 90 dB or more was evaluated as "large", 80 dB or more and 90 dB as "medium", 75 dB or more and less than 80 dB as "small", 70 dB or more and less than 75 dB as "minute", and less than 70 dB as "absent". The measurement was performed in the idling state because the generation of sound is most noticeable at the time of low rotation of the engine.

<Belt endurance running test>
FIG. 5 shows a pulley layout of a belt travel tester 30 for evaluating the durability of the V-ribbed belt B. As shown in FIG.

  The belt traveling test machine 30 is disposed on the upper side of a large diameter rib pulley (a driven pulley on the upper side is a driven pulley, and a lower side is a driving pulley) 31 and 32 disposed on the upper and lower pulleys. It consists of a small diameter rib pulley 33 with a pulley diameter of 45 mm. The small diameter rib pulley 33 is positioned so that the belt winding angle is 90 °.

  About each V ribbed belt B of Examples 1-6 and Comparative Examples 1-7, while winding around three rib pulleys 51-53, the small diameter rib pulley 53 is pulled laterally so that the set weight of 834N is loaded, A belt running test was conducted in which the lower rib pulley 32, which is a driving pulley, was rotated at a rotational speed of 4900 rpm under an ambient temperature of 23 ° C. And time until a crack generate | occur | produces on the rib surface was measured.

<Measurement of aspect ratio, short hole diameter, direction of recess>
The pulley contact surface of each of the V-ribbed belts B of Examples 1 to 6 and Comparative Examples 1 to 7 is observed with a microscope, and the dimension in the longitudinal direction and the dimension in the lateral direction (short pore diameter) of 50 recesses. The aspect ratio was calculated. Moreover, it measured also about the direction of the longitudinal direction. The average value was determined from the measurement results of 50 recesses. When a rectangle is drawn such that four sides contact one or more points on the contour of the recess on the pulley contact surface, the direction of the long side is the longitudinal direction, and the direction orthogonal to this is the lateral direction.

(Test evaluation result)
With respect to each of V-ribbed belts B of Examples 1 to 6 and Comparative Examples 1 to 7, presence or absence of recess formation, aspect ratio of recess shape, angle in longitudinal direction, short pore diameter of recess, sounding when wet, and crack generation traveling time Is shown in Table 1.

  First, in Comparative Example 1 in which the concave portion is not provided, the sound generation after the water is large.

  In terms of the aspect ratio of the recess, in the range from 1.26 of Example 1 to 9.77 of Example 2, there is no or slight sound emission after water immersion. On the other hand, in the case of Comparative Example 2 in which the aspect ratio is 1.06, which is smaller than that of Example 1, the sound generation after the water is in the middle. Therefore, it is thought that the sound generation after the water can be suppressed by forming the concave portion having a long shape in one direction.

  Even in the case of Comparative Example 3 having an aspect ratio of 10.49, no sounding after water exposure was found, but in this example, the crack occurrence traveling time is 437 hours, which is significantly higher than that of Example 2 of 498 hours. Short. From this, it can be seen that the belt strength is deteriorated if the aspect ratio is too large.

  From the above, it is considered desirable that the average of the aspect ratio is about 1.2 or more and about 10 or less.

  In addition, in Example 3 in which the longitudinal angle is + 42.1 ° and Example 5 in which the angle in the longitudinal direction is −43.5 °, the sound generation after water is absent or slight. On the other hand, Comparative Example 4 in which the angle in the longitudinal direction is + 49.4 ° and Comparative Example 5 in which the angle is −47.0 ° is large, and Comparative Example 5 in which + 89.9 ° is large. Therefore, when the average in the longitudinal direction is aligned with the belt sliding direction, the sound generation after water deposition becomes smaller, and when the sliding direction of the belt is 0 °, it is about -45 ° to + 45 °. Is considered desirable.

  Further, in Example 6 in which the short hole diameter is 181 μm, the crack generation traveling time is 491 hours, which is slightly shorter than 512 hours in Example 1 in which the short hole diameter is 121 μm. However, Comparative Example 7 in which the short pore diameter is 211 μm is significantly short, 425 hours, and there is a significant difference in Example 6 as well. From these facts, it is considered that the short pore diameter is desirably about 200 μm or less.

  The friction transmission belt of the present disclosure can suppress abnormal noise during water immersion while maintaining strength and the like, and is also useful for accessory transmission belt transmissions for automobiles and belt transmissions for general industrial use.

DESCRIPTION OF SYMBOLS 10 V-ribbed belt main body 11 compression rubber layer 11 'non-crosslinked rubber sheet 12 adhesive rubber layer 12a inner part 12a' non-crosslinked rubber sheet 12b outer part 12b 'non-crosslinked rubber sheet 13 back rubber layer 13' rubber layer 14 core 14 'yarn 15 V Rib 16 Recess 17 Sliding Direction 20 Accessory Drive Belt Transmission Device 21 Power Steering Pulley 22 AC Generator Pulley 23 Tensioner Pulley 24 Water Pump Pulley 25 Crankshaft Pulley 26 Air Conditioner Pulley 30 Belt Running Tester 31 Rib Pulley 32 Rib Pulley 33 Rib Pulley

Claims (3)

A friction transmission belt including a pulley contact portion formed of a rubber composition on a belt body,
A plurality of recesses are formed in the pulley contact surface of the pulley contact portion,
The opening of the recess in the pulley contact surface has a shape elongated in one, the average aspect ratio of the shape Ri der and 10 or less 1.2 or more,
The opening is either included in the pulley contacting the surface or friction transmission belt according to claim Rukoto that Sessu only at one end in the width direction of the pulley contact surfaces. In the friction drive belt of claim 1,
The longitudinal orientations of the openings in the plurality of recesses have a distribution,
In the pulley contact surface, when the sliding direction of the friction transmission belt is an angle of 0 °, the average of the longitudinal angle of the opening is in the range of −45 ° to + 45 °. Transmission belt. The friction transmission belt according to claim 1 or 2
In the pulley contact surface, the dimension of the direction perpendicular to the longitudinal direction of the opening is not less than 103 μm and not more than 200 μm.

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