JP2006266280A - Transmission belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a friction-type transmission belt which diminishes noise caused by stick-slip or misalignment and is excellent in abrasion resistance. <P>SOLUTION: In the V-ribbed belt 1 in which core wires 3 are embedded in the longitudinal direction of the belt and a compression rubber layer 4 is arranged, the compression rubber layer 4 is formed of rubber composition composed of 5-30 parts by weight of thermosetting resin powder and 10-40 parts by weight of short fiber with respect to 100 parts by weight of rubber. Therefore, a low coefficient of friction can be maintained even after the effect of the short fiber has been reduced by running and the noise caused by the stick-slip or misalignment can be prevented over a long period of time. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a transmission belt, and more particularly to a friction-type transmission belt that reduces sound generation due to stick-slip or misalignment and has excellent wear resistance.

  Important characteristics of the friction transmission belt include not only that power is transmitted but also that no abnormal noise is generated during use, and excellent durability and wear resistance. In order to meet these characteristics, organic short fibers such as nylon and meta- or para-aramid are blended, and the side of the belt is covered with them to improve sound resistance, wear resistance, and adhesive wear resistance. .

  Particularly in recent automobile engines, lean combustion is performed in order to reduce the size, improve fuel consumption, and reduce exhaust gas. For this reason, engine rotational fluctuation and vibration are larger than those of conventional engines. In addition, the use of serpentine in the auxiliary machine belt has made the engine layout smaller and the bending angle smaller, and the load on the auxiliary machine belt has further increased, and problems of abnormal noise due to misalignment and stick slip have become obvious.

  Conventionally, as described above, organic monofilaments are blended into the compressed rubber layer and the fibers protrude from the belt side surface to cover the belt side surface to reduce the friction coefficient and prevent abnormal noise. It was common.

In addition, it has been proposed to apply a powder such as talc to the rib part surface, or to attach silicon oil to reduce the friction coefficient of the rib part surface (see, for example, Patent Document 1). Furthermore, in order to make the friction coefficient of the belt surface substantially constant over a long period of time, a transmission belt is disclosed in which a porous particle such as activated carbon is adsorbed with silicon oil (for example, Patent Document 2). reference).
No. 7-31006 JP-A-5-132586

  However, in the method of covering the belt side surface with organic short fibers, if the amount of organic short fibers increases, even if the surface is subjected to adhesion treatment, there will be a problem in physical properties and processability, so the amount of mixing is limited. At the same time, there has been a problem that the effect of reducing the friction coefficient is reduced when the short fibers become stumps due to dropping off or abrasion of the organic short fibers protruding on the surface by belt running.

  In addition, the method of applying powder such as talc to the rib surface of the above-mentioned patent document and attaching silicon oil is aimed at reducing the slip noise in the initial running stage of the belt. Although the effect can be expected, in the belt after running for a long time, the lubricant easily scatters from the surface, so the effect of reducing the friction coefficient on the belt surface could not be maintained for a long time. On the other hand, in a transmission belt containing porous particles adsorbed with silicon oil, it is difficult to uniformly disperse a predetermined amount of the porous particles in the rubber in order to exert a bleeding effect on the belt surface. there were. In addition, only the porous particles close to the belt surface layer easily exert a bleeding effect, and it was difficult to expect the effect of the porous particles embedded inside.

  The present invention is intended to improve such problems, and an object thereof is to provide a friction-type transmission belt that reduces sound generation due to stick-slip and misalignment and is excellent in wear resistance.

  That is, in the invention described in claim 1 of the present application, a power transmission belt in which a core wire is embedded along the longitudinal direction of the belt and a compressed rubber layer is disposed, and the compression rubber layer is thermosetting with respect to 100 parts by weight of rubber. By using a rubber composition containing 5 to 30 parts by weight of resin powder and 10 to 40 parts by weight of short fibers, a low friction coefficient can be maintained even after the effect of short fibers has been reduced by running, Suppresses pronunciation due to misalignment and stick-slip for a long time.

  The thermosetting resin usually has a lower coefficient of friction than the rubber composition, and the effect persists because the short fibers are present on the surface even after being worn or dropped. For these purposes, it may be possible to use a thermoplastic resin. However, when the transmission belt is used under severe conditions, the temperature of the compression rubber layer may become high. Polyolefin thermoplastic resins that are generally used for the purpose of reducing the risk of melting and adhering to a pulley or the like during running, or a deterioration in physical properties of rubber. It is also conceivable to blend a high melting point resin, but there are many problems in terms of high cost and affinity at the interface with rubber. From the above, when the thermosetting resin is blended, the restriction on the use condition of the transmission belt is reduced, which is effective.

  In the invention according to claim 2, when the average primary particle size of the thermosetting resin is 10 to 200 μm, when the thermosetting resin is a phenol resin, a part of the rubber component constituting the rubber composition or When all are ethylene-α-olefin elastomers, the transmission belt is a V-ribbed belt comprising an adhesive rubber having a core wire embedded along the longitudinal direction of the belt and a compressed rubber layer having a plurality of rib portions extending in the circumferential direction of the belt. Includes some cases.

  As described above, the present invention has excellent bending fatigue resistance and heat resistance by suppressing the generation of abnormal noise during traveling of the transmission belt, in particular, the generation of abnormal noise during water injection, and is also resistant to cold, abrasion, and adhesion. A highly durable friction transmission belt having wear characteristics can be obtained.

  A V-ribbed belt 1 shown in FIG. 1 has a cord 3 made of a high-strength, low-stretch cord made of polyester fiber, aramid fiber, or glass fiber embedded in an adhesive rubber layer 2 and an elastic body below it. It has the compression rubber layer 4 which is a layer. The compressed rubber layer 4 is provided with a plurality of rib portions 7 having a substantially triangular cross section extending in the longitudinal direction of the belt, and a rubberized canvas 5 attached to the belt surface.

  In the present invention, the thermosetting resin contained in the compressed rubber layer 4 includes a phenol resin, an epoxy resin, a polyester resin, a urea resin, a melamine resin, and the like, and the phenol resin is particularly preferable from the viewpoint of durability. The thermosetting phenol resin is a resin obtained from phenols and aldehydes, and is usually a novolak type phenol resin. As the type of phenol resin, those modified with cresol, alkylphenol, resorcin, etc., or those modified with cashew oil, tall oil, linseed oil, etc. can be used in addition to the unmodified resin.

It is necessary to advance the three-dimensional crosslinking reaction to a predetermined hardness by applying a curing agent and heat to these thermosetting resins. As the curing agent, hexamethylenetetramine, polymethylol melamine or the like is used. By mixing and heating the thermosetting resin and the curing agent as described above, a three-dimensionally cross-linked cured product is obtained, and this cured product is processed into a powder form to a predetermined particle size and used.
However, this three-dimensional cross-linking may be in a complete state, but is preferably in an incomplete state. Here, the complete state means a state in which crosslinking proceeds and the hardness does not increase any more.

  These thermosetting resins may be used alone or may be added with a sliding agent such as graphite, carbon fiber, aramid or the like.

  The amount of the thermosetting resin is 5 to 30 parts by weight, preferably 10 to 15 parts by weight, based on 100 parts by weight of the rubber component. The rubber component is not particularly limited, but it is desirable to use an ethylene-α-olefin elastomer having excellent heat resistance and cold resistance in consideration of the use environment of the transmission belt. In addition, the rubber composition used in the present invention uses powdery reinforcing agents such as carbon black and silica usually used in rubber compositions, reinforcing short fibers such as organic short fibers, and chemicals such as oil and vulcanizing agents. It is possible.

  Further, as the short fibers contained in the compressed rubber layer 4, polyamide short fibers such as 6 nylon, 66 nylon, and 610 nylon can be used. The polyamide short fibers are preferably in the range of about 1 to 8 mm, and the thickness is preferably 5 to 10 denier. In addition to the polyamide short fibers, cotton, rayon, and aramid fibers can be used for the compressed rubber layer 4, but stick slip noise can be more effectively reduced by using the polyamide short fibers alone.

  And the compounding quantity of all the short fibers with respect to the raw material rubber of the compression rubber layer 4 is set to 10-40 weight part with respect to 100 mass parts of rubber | gum. By setting the blending amount of all short fibers to 10 parts by weight or more, the difference in transmission force between DRY and WET of the transmission belt can be reduced, and the generation of abnormal noise by reducing the occurrence of stick-slip noise. It can be reduced. If the blending amount of all short fibers exceeds 40 parts by weight, the dispersion of the short fibers in the raw rubber is deteriorated and the rubber physical properties are deteriorated. Therefore, the total short fibers should be set to a blending amount of 40 parts by weight or less. preferable.

  The rubber composition used in the present invention can be produced using equipment such as commonly used Banbury mixers, open rolls, and twin-screw kneaders.

  As the core wire 3, a polyester fiber, an aramid fiber, and a glass fiber are used, and the total number of deniers obtained by twisting together polyester fiber filament groups mainly composed of ethylene-2,6-naphthalate 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 suitable third components are added before the completion of the polymerization of ethylene-2,6-naphthalate, 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, 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 the length is less than 1.0 mm, the cord cannot ride on the adjacent cord and cannot be wound. On the other hand, if the length 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, but if necessary, normal agents such as enhancers such as carbon black and silica, fillers such as calcium carbonate and talc, plasticizers, stabilizers, processing aids, and coloring agents. What is used for rubber compounding 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.

  An example of the manufacturing method of the V-ribbed belt 1 is as follows. First, one or more cover canvases and a cushion rubber layer are wound around the circumferential surface of a cylindrical molding drum, and then a cord made of a rope is spun into a spiral shape, and then a compression rubber layer is wound in order. After obtaining a laminate, this is vulcanized to obtain a vulcanized sleeve.

  Next, the vulcanization sleeve is hung on a driving roll and a driven roll and travels under a predetermined tension. Further, the rotated grinding wheel is moved so as to abut on the traveling vulcanization sleeve to compress the vulcanization sleeve. A plurality of groove portions of 3 to 100 are ground at a time on the surface of the rubber layer.

  The vulcanization sleeve thus obtained is removed from the drive roll and driven roll, the vulcanization sleeve is run on other drive rolls and driven rolls, and is cut into a predetermined width by a cutter. Finish in a V-ribbed belt. However, it is not limited to this manufacturing method, and it is not a method of forming a rib shape by polishing, and no problem occurs even if a molding method using a mold having a rib shape is employed.

  In the present invention, in addition to the above-mentioned V-ribbed belt, a low-edge V-belt 21 having rubber canvas 22 attached only to the upper and lower surfaces of the belt as shown in FIG. 2 also belongs to the technical scope of the present invention. . 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.

Hereinafter, the present invention will be described in more detail with reference to examples.
Examples 1-3, Comparative Examples 1-3
In the V-ribbed belt manufactured in this example, a cord made of a polyester fiber rope was embedded in the adhesive rubber layer, and two plies of a cotton canvas with rubber were laminated on the upper side and provided on the other side of the adhesive rubber layer. A compressed rubber layer is provided with three ribs in the longitudinal direction of the belt.

  Here, a compressed rubber layer was prepared from the rubber composition shown in Table 1, kneaded with a Banbury mixer, and then rolled with a calender roll. The compressed rubber layer contains short fibers and is oriented in the belt width direction. The phenol resin used was heated at 160 ° C. for 2 minutes, and the crosslinked product was added as a powder pulverized by a pulverizer.

  Table 1 shows the results of the heat resistance running test, the sound generation limit tension test, and the evaluation of workability of the V-ribbed belt thus obtained.

  The running test machine used for the evaluation of the heat resistant running test is one in which a drive pulley, a driven pulley (diameter 120 mm), an idler pulley (diameter 85 mm), and a tension pulley (diameter 45 mm) are arranged in this order. The pulley layout is shown in FIG. A belt is hung on each pulley of the testing machine, and the drive pulley is loaded so that the ambient temperature is 130 ° C., the rotation speed of the drive pulley is 4900 rpm, and the belt tension is 559 N / 3 ribs, and then run for 500 hours. The number of cracks in the later compressed rubber layer was examined. The belt and pulley surfaces after running were observed.

  In the sound generation limit tension test, the obtained V-ribbed belt was 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 having a clutch mechanism. Then, the squeal generated when the second driven pulley was rotated and rotated while the drive pulley was rotated at 5,000 rpm, and the tone generation limit tension, which was the minimum tension of the belt at this time, were measured. The smaller this tension, the harder it is to generate abnormal noise. In Table 1, the part where no numerical value is shown indicates that the pronunciation did not stop even when the tension was increased.

  In the evaluation of the workability at the time of belt production, ○ indicates that the rubber sheeting can be performed smoothly, and there is no problem of opening a hole in the sheet, and × indicates that the seated rubber sheet is perforated. This is the case.

  Examples 1 to 3 show that the sound production limit tension is lower than that of Comparative Example 1, and it is difficult to produce sound. In Comparative Example 2, the sound production limit tension at the time of a new article is equal to that in the example, but the sound production limit tension after running-in is high. This is due to the fact that the short fiber was worn and dropped during the running-in, although the short fiber was effective when it was new. Further, in Comparative Example 2, since a large amount of short fibers are blended, it is clear that cracks are likely to occur due to heat-resistant running and that workability is poor.

  Comparative Example 3 is an example in which the thermoplastic resin polyethylene is blended, but there is no problem in the sound production limit tension and workability before and after running, but there is a problem that the resin melts and adheres to the pulley during the heat resistant running test. It has been seen.

A perspective view of a V-ribbed belt is shown as an example of a transmission belt according to the present invention. It is sectional drawing of the low edge V belt which is another example of the power transmission belt which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 V ribbed belt 2,24 Adhesive rubber layer 3,23 Core wire 4,26 Compression rubber layer 5,22 Canvas with rubber 7 Rib part 21 Low edge V belt

Claims (5)

  A transmission belt in which a core wire is embedded along the longitudinal direction of the belt and a compressed rubber layer is disposed, and the compressed rubber layer has 5 to 30 parts by weight of a thermosetting resin powder with respect to 100 parts by weight of rubber, and a short A power transmission belt comprising a rubber composition containing 10 to 40 parts by weight of fibers.   The transmission belt according to claim 1, wherein the thermosetting resin has an average primary particle size of 10 to 200 μm.   The power transmission belt according to claim 1 or 2, wherein the thermosetting resin is a phenol resin.   The power transmission belt according to any one of claims 1 to 3, wherein a part or all of a rubber component constituting the rubber composition is an ethylene-α-olefin elastomer. 5. The transmission belt according to claim 1, wherein the transmission belt is a V-ribbed belt comprising an adhesive rubber having a core wire embedded in the longitudinal direction of the belt and a compressed rubber layer having a plurality of rib portions extending in the circumferential direction of the belt.

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