JP2006029493A - V-ribbed belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly durable V-ribbed belt having bending fatigue resistance, heat resistance, cold resistance, wear resistance, and adhesive wear resistance while suppressing core pop-out from the side face of the belt even when using a non-polar polymer having poor adhesive force such as an ethylene-α-olefin elastomer. <P>SOLUTION: The V-ribbed belt 1 comprises an extensive rubber layer 4 provided on the back of the belt, a compressive rubber layer 5 on which a plurality of rib portions are provided extending in the longitudinal direction of the belt, and core wires 2 embedded along the longitudinal direction of the belt. No cover canvas is laminated on the back of the belt, the ethylene-α-olefin elastomer is used for each of the extensive rubber layer 4 and the compressive rubber layer 5, and at least the compressive rubber layer 5 contains short fibers. An adhesive rubber layer 3 is arranged around the core wires 2, but no adhesive rubber layer exists on at least one of the side of the extensive rubber layer 4 and the side of the compressive rubber layer 5. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a V-ribbed belt. More specifically, a cover canvas is not used on the back of the belt, a specific ethylene-α-olefin elastomer is used for both the stretch rubber layer and the compression rubber layer, and the stretch rubber layer side and the compression are used. The present invention relates to a highly durable V-ribbed belt having excellent bending fatigue resistance and heat resistance, and having cold resistance, abrasion resistance, and adhesive wear resistance by not having an adhesive rubber layer on at least one side of the rubber layer.

  In recent years, the ambient temperature around the engine room of automobiles has risen compared to the conventional environment due to social demands for energy saving and compactness. Along with this, the operating environment temperature of the V-ribbed belt has also increased. Conventionally, natural rubber, styrene-butadiene rubber, and chloroprene rubber have been mainly used for the V-ribbed belt. However, there has been a problem that cracks occur early in the cured compressed rubber layer under a high temperature atmosphere.

  With regard to such an early failure phenomenon of the belt, improvement of heat resistance of chloroprene rubber has been studied conventionally, and although some improvement has been made, there is a limit as long as chloroprene rubber is used, and it is sufficient at present. It has not yet been effective.

For this reason, recently, it has been proposed to use an ethylene-α-olefin elastomer reinforced with a metal salt of an α-β-unsaturated organic acid in place of chloroprene rubber for a transmission belt, which is disclosed in Patent Document 1. Yes.
Japanese National Patent Publication No. 9-500930

  However, ethylene-α-olefin elastomers such as ethylene-propylene-diene rubbers are superior in long-term heat resistance and cold resistance compared to chloroprene rubber, but are electrostatically charged with the core because they are nonpolar polymers. Since the interaction is weak and the adhesiveness with the core wire is poor, the core wire protrudes from the side surface of the belt when it is wound around a small-diameter pulley, resulting in a problem that the service life is shortened. Hereinafter, this defect is referred to as a core pop-out.

  The present invention addresses this situation in view of the above-described circumstances, and suppresses cord pop-out from the side surface of the belt even when a nonpolar polymer such as an ethylene-α-olefin elastomer is used. In addition, a highly durable V-ribbed belt having bending fatigue, heat resistance, cold resistance, wear resistance, and adhesive wear resistance is provided.

  That is, the invention according to claim 1 does not have a cover canvas laminated on the back of the belt, uses an ethylene-α-olefin elastomer for both the stretch rubber layer and the compression rubber layer, and at least the compression rubber layer. Among the adhesive rubber layers that contain short fibers and are arranged around the core wire, the adhesive rubber layer does not exist on at least one of the stretched rubber layer side and the compressed rubber layer side. It is possible to prevent pop-outs. The reason for this is that if there is a large elastic modulus on the back of the belt, that is, a cover canvas layer, a strong restraining force in the belt width direction is generated on the back of the belt when the belt is bent. Since it has become clear that stress is generated in the belt width direction in the vicinity of the line, this is the result of eliminating the cover canvas, which is a member having a different elastic modulus. Furthermore, since the removal of the cover canvas facilitates bending in the belt longitudinal direction, the bending fatigue resistance can also be improved.

  Also, by removing one adhesive rubber layer, the difference in elastic modulus between members existing in the belt cross section other than the core wire can be further reduced, and the adhesive force between the rubber and the core wire can be maintained to some extent. Is effective. Furthermore, the configuration in which the adhesive rubber layer is not used at all is concerned about a decrease in the adhesive strength between the core wire and the rubber. However, as a result of the investigation, the effect of the decrease in the adhesive strength in the V-ribbed belt using the ethylene-α-olefin elastomer It has been clarified that the presence of a member having a different elastic modulus is prioritized and greatly affects the pop-out of the cord from the side of the belt.

  That is, by adopting the configuration as in claim 1, a life reduction due to pop-out of the core wire is prevented, bending fatigue is greatly improved, and a V-ribbed belt having excellent heat resistance, cold resistance, and wear resistance is achieved. Can be finished.

  The invention according to claim 2 of the present invention uses an ethylene-α-olefin elastomer having an ethylene content of 40 to 60% and a Mooney viscosity of 40 to 60 for the stretch rubber layer, and a polymer having such characteristics is used. Even if there is no adhesive rubber layer, it is possible to maintain a certain amount of adhesive force by ensuring sufficient rubber flow around the core wire, which is a concern when the cover canvas is removed. A V-ribbed belt having sufficient abrasion resistance and adhesive wear resistance on the back surface and having bending fatigue, heat resistance and cold resistance can be obtained. In these ranges, if the ethylene content is less than 40%, the adhesive wear on the back surface of the belt becomes remarkable, and if it is 70% or more, a problem occurs in workability and the bending fatigue resistance is inferior. If the Mooney viscosity is 40 or less, the required physical property value is not satisfied. If the Mooney viscosity is 60 or more, the flow into the vicinity of the core wire is insufficient and the decrease in the adhesive strength becomes remarkable.

  The invention according to claim 3 of the present invention uses an ethylene-α-olefin elastomer having an ethylene content of 50 to 70% and a Mooney viscosity of 60 to 70 for the compressed rubber layer, so that even if no adhesive rubber layer is present, A sufficient amount of rubber can flow around the wire, and it is possible to maintain a certain level of adhesive force due to the anchor effect. This makes it possible to maintain cord bending fatigue, heat resistance, cold resistance, wear resistance, and adhesive wear resistance. The V-ribbed belt can be provided.

  In the invention according to claim 4, the compression rubber layer has a total amount of reinforcing short fibers of 10 to 40 parts by weight with respect to 100 parts by weight of rubber. Effects such as reduction of sound generation can be obtained. If the amount of reinforcing short fibers is less than 10 parts by weight, the effect of suppressing wear resistance and abnormal noise is low, and if it exceeds 40 parts by weight, the composition is inferior in bending crack resistance and inferior in moldability.

  In the invention according to claim 5 of the present invention, the stretch rubber layer has a total amount of reinforcing short fibers of 0 to 30 parts by weight with respect to 100 parts by weight of rubber. It is possible to suppress the occurrence of wear and noise. It is desirable that the blend of short fibers in the stretch rubber layer is made as small as possible from the background of removing the cover canvas having a higher elastic modulus than the rubber layer, and it does not decrease the bending fatigue resistance. It is necessary to avoid blending.

In the present invention, a cover canvas is not laminated on the back of the belt, an ethylene-α-olefin elastomer is used for both the stretch rubber layer and the compression rubber layer, at least the compression rubber layer contains short fibers, and Out of the adhesive rubber layers arranged around the core wire, the core wire pops out from the side of the belt by satisfying the four requirements of having no adhesive rubber layer on at least one of the stretch rubber layer side and the compression rubber layer side. In addition, the conventional belt components can be eliminated, and an inexpensive belt can be provided.
In particular, in a V-ribbed belt using an ethylene-α-olefin elastomer, even when a nonpolar polymer such as an ethylene-α-olefin elastomer having a weak adhesive force is used by not laminating a cover canvas on the back surface, It is possible to obtain a highly durable V-ribbed belt that suppresses the core wire pop-out and has bending fatigue, heat resistance, cold resistance, wear resistance, and adhesive wear resistance.

  A V-ribbed belt 1 shown in FIG. 1 has a stretch rubber layer 4 disposed on the back of the belt, and a cord 2 made of a high strength and low elongation cord made of polyester fiber, aramid fiber, glass fiber or the like is used as a stretch rubber layer. It is embedded in the adhesive rubber layer 3 and the compressed rubber layer 5 arranged on the 4 side. The compressed rubber layer 5 is provided with a plurality of rib portions 9 having a substantially triangular cross section extending in the longitudinal direction of the belt. Note that the cover canvas is not laminated on the back of the belt.

  A V-ribbed belt 6 shown in FIG. 2 has a stretch rubber layer 4 disposed on the back surface of the belt, and a cord 2 made of a high-strength, low-stretch cord made of polyester fiber, aramid fiber, glass fiber or the like is used as the stretch rubber 4. Embedded in the adhesive rubber layer 3 disposed on the compressed rubber layer 5 side, and has a compressed rubber layer 5 as an elastic layer on the lower side. The compressed rubber layer 5 is provided with a plurality of rib portions 9 having a substantially triangular cross section extending in the longitudinal direction of the belt. Note that the cover canvas is not laminated on the back of the belt.

  A V-ribbed belt 7 shown in FIG. 3 has an elastic rubber layer 4 disposed on the back surface of the belt, and a cord 2 made of a high strength and low elongation cord made of polyester fiber, aramid fiber, glass fiber or the like is used as the elastic rubber 4. And the compression rubber layer 5. The compressed rubber layer 5 is provided with a plurality of rib portions 9 having a substantially triangular cross section extending in the longitudinal direction of the belt. Note that the cover canvas is not laminated on the back of the belt.

  The ethylene-α-olefin elastomer used for the stretched rubber layer 4 and the compressed rubber layer 5 is a rubber made of ethylene-propylene rubber (EPR) or ethylene-propylene-diene monomer (EPDM). Examples of diene monomers include dicyclopentadiene, methylene norbornene, ethylidene norbornene, 1,4-hexadiene, cyclooctadiene, and the like.

  In the stretch rubber layer 4, an ethylene-α-olefin elastomer having an ethylene content of 40 to 60% and a Mooney viscosity of 40 to 60 is used. By using a polymer having such characteristics, there is no adhesive rubber layer. However, it is possible to maintain a certain level of adhesive force by ensuring sufficient rubber flow around the core wire, and the performance required for the stretched rubber layer, that is, wear resistance, adhesive wear resistance, It is possible to satisfy the bending fatigue resistance.

  The compressed rubber layer 5 uses an ethylene-α-olefin elastomer having an ethylene content of 50 to 70% and a Mooney viscosity of 60 to 70, so that the rubber flows around the core wire even if no adhesive rubber layer is present. Can be secured sufficiently, and it is possible to maintain a certain degree of adhesive force due to the anchor effect, and to satisfy the performance required for the compressed rubber layer, that is, the wear resistance and the adhesive wear resistance.

  The characteristics of the polymers used for the stretched rubber layer 4 and the compressed rubber layer 5 are different because the characteristics required for each layer are different. For example, in the case of wear resistance, the compressed rubber layer 5 that transmits power is required to have a higher level of wear resistance. However, a low Mooney viscosity polymer is suitable for ensuring the inflow of rubber around the core wire in each layer, but the wear resistance, adhesive wear resistance, etc. tend to decrease. Considering such a plurality of factors, the optimum polymer characteristics used for each layer are set.

  To the stretched rubber layer 4 and the compressed rubber layer 5, peroxide is added as a vulcanizing agent for ethylene-α-olefin elastomer, and N, N′-m-phenylene dimaleimide is added as a co-crosslinking agent. The addition amount of N, N′-m-phenylene dimaleimide is 0.2 to 10 parts by weight with respect to 100 parts by weight of the ethylene-α-olefin elastomer. The effect of improving wear resistance and adhesive wear resistance is small, and when the amount exceeds 10 parts by weight, the elongation of the vulcanized rubber is remarkably lowered, resulting in a problem in bending resistance.

  Examples of the organic peroxide include diacyl peroxide, peroxyester, diallyl peroxide, di-t-butyl peroxide, t-butylcumyl peroxide, and dicumyl peroxide that are usually used for crosslinking of rubber and resin. Oxide, 2,5-dimethyl-2,5-di (t-butylperoxy) -hexane-3,1,3-bis (t-butylperoxy-isopropyl) benzene, 1,1-di-butylperoxy -3,3,5-trimethylcyclohexane and the like, and those having a half-life of 1 minute by thermal decomposition of 150 to 250 ° C are preferred. The addition amount is about 1 to 8 parts by weight, preferably 1.5 to 4 parts by weight, based on 100 parts by weight of the ethylene-α-olefin elastomer.

  The stretched rubber layer 4 is a total addition amount of reinforcing short fibers made of nylon 6, nylon 66, polyester, cotton, p-aramid, m-aramid, cotton, PBO (polybenzoxazole), etc. with respect to 100 parts by weight of rubber. Is 0 to 30 parts by weight, and it is possible to suppress the occurrence of adhesive wear and abnormal noise, which is a concern when there is no cover canvas. In addition, it is desirable that the blend of short fibers in the stretch rubber layer is made as small as possible from the background of removing the cover canvas having a higher elastic modulus than the rubber layer, and it does not decrease the bending fatigue resistance. It is necessary to avoid the blending of.

  Further, the compressed rubber layer 5 is mixed with reinforcing short fibers made of nylon 6, nylon 66, polyester, cotton, p-aramid, m-aramid, cotton, PBO (polybenzoxazole), etc. The side pressure resistance is improved, and the surface of the compressed rubber layer 5 which is a surface in contact with the pulley is polished by a grinder to project the short fibers. The friction coefficient of the surface of the compressed rubber layer 5 is reduced, and noise during belt running is reduced.

  The rubber compositions of the stretched rubber layer 4 and the compressed rubber layer 5 include various fillers such as carbon black, calcium carbonate, silica and clay, plasticizers, anti-aging agents, processing aids, etc. It can mix | blend without specifically limiting. The method for mixing the components is not particularly limited, and can be kneaded appropriately by known means and methods using, for example, a Banbury mixer, a kneader or the like.

  When the adhesive rubber layer 3 is provided, the rubber composition forming the adhesive rubber layer 3 is subjected to sulfur-based crosslinking, and the use of sulfur crosslinking can suppress a decrease in adhesive strength as much as possible. . An ethylene-α-olefin elastomer composition is also used for the adhesive rubber layer 3, but in order to adhere well to the core wire 2, sulfur vulcanization not containing peroxide is used.

  An example of the manufacturing method of the V-ribbed belt 1 is as follows. First, after applying a release agent to the peripheral surface of a cylindrical molding drum, after winding one or more stretched rubber layers, the adhesive rubber layer is wound, and a cord made of rope is spirally wound on this Then, a compressed rubber layer is sequentially wound to obtain a laminated body, which is then 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.
Embodiments of the present invention will be described below with reference to the accompanying drawings.

Examples 1-3, Comparative Examples 1-2
In the V-ribbed belt manufactured in this example, a cord made of polyester fiber rope was used, a cover canvas layer was not provided, a stretch rubber layer was provided on the back of the belt, and a compression rubber layer was provided on the opposite side. Ribs are arranged in the longitudinal direction of the belt. Based on the shape, three types were prepared: those without an adhesive rubber layer on the stretched rubber layer side, those without an adhesive rubber layer on the compression rubber layer side, and those without any adhesive rubber layer.

  Here, a compressed rubber layer, an extended rubber layer, and an adhesive rubber layer were prepared from the rubber composition shown in Table 1, kneaded with a Banbury mixer, and then rolled with a calendar roll. Both the compressed rubber layer and the stretched rubber layer contain short fibers and are oriented in the belt width direction.

  An example of the manufacturing method of the V-ribbed belt 1 is as follows. First, one or more cover canvases and an adhesive 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 further a compressed rubber layer is wound in order. After obtaining a laminate, this was 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 3 to 100 groove-shaped portions were ground at a time on the rubber layer surface.

  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. Finished into a V-ribbed belt.

  Table 2 shows the results of the heat-resistant and high-tensile test (core wire pop-out test) and the results of the heat-resistant bendability test of the V-ribbed belt thus obtained.

  The running test machine used for the evaluation of the high-tension durability test has a driving pulley, a driven pulley (diameter 120 mm), and a tension pulley (diameter 55 mm) arranged in this order. The pulley layout is shown in FIG. A belt is hung on each pulley of the testing machine, and after applying a load to the drive pulley so that the ambient temperature is 85 ° C., the rotation speed of the drive pulley is 4900 rpm, and the belt tension is 834 N / 3 rib, the belt is run. The pop-out occurrence time of was investigated.

  The running test machine used for the evaluation of the heat-resistant flexibility test has a driving pulley, a driven pulley (diameter 120 mm), an idler pulley (diameter 85 mm), and a tension pulley (diameter 45 mm) arranged in this order. The pulley layout is shown in FIG. A belt is hung on each pulley of the test machine, and after applying a load to the drive pulley so that the ambient temperature is 120 ° C., the rotation speed of the drive pulley is 4,900 rpm, and the belt tension is 559 N / 3 rib, run the belt. We examined the pop-out occurrence time of the core wire.

  When Examples 1 and 2 were compared with Comparative Example 2, it was found that no pop-out was observed regardless of the position of the adhesive rubber layer when there was no cover canvas. Further, in the comparison between the case where both the cover canvas and the adhesive rubber layer are present as in Example 3 and Comparative Example 1, the occurrence of pop-out is less likely to occur when neither is present as in Example 3. I understood. This is presumably because the stress due to deformation was distributed relatively evenly and local stress concentration was suppressed by reducing the number of materials having different elastic moduli in the belt cross section as much as possible.

  The V-ribbed belt of the present invention can be widely applied as a transmission belt for automobiles and general industries.

It is a section perspective view of the V ribbed belt concerning the present invention. It is a cross-sectional perspective view of another V-ribbed belt according to the present invention. FIG. 10 is a cross-sectional perspective view of still another V-ribbed belt according to the present invention. The pulley layout of the running test machine used for the evaluation of the high tension durability test is shown. The pulley layout of the running test machine used for the evaluation of the heat resistance flexibility test is shown.

Explanation of symbols

1 V-ribbed belt 2 Core wire 3 Adhesive rubber layer 4 Stretch rubber layer 5 Compression rubber layer 9 Rib part

Claims (5)

A V-ribbed belt having a stretched rubber layer provided on the belt back surface portion, a compressed rubber layer provided with a plurality of rib portions extending in the belt longitudinal direction, and a core wire embedded along the belt longitudinal direction, A V-ribbed belt characterized by comprising the requirements of A, B, C and D.
A. The cover canvas is not laminated on the back of the belt.
B. An ethylene-α-olefin elastomer is used for both the stretch rubber layer and the compression rubber layer.
C. At least the compressed rubber layer should contain short fibers.
D. The adhesive rubber layer arranged around the core wire should not exist on at least one of the stretch rubber layer side and the compressed rubber layer side.   The V-ribbed belt according to claim 1, wherein an ethylene-α-olefin elastomer having an ethylene content of 40 to 60% and a Mooney viscosity of 40 to 60 is used for the stretch rubber layer.   The V-ribbed belt according to claim 1, wherein an ethylene-α-olefin elastomer having an ethylene content of 50 to 70% and a Mooney viscosity of 60 to 70 is used for the compression rubber layer.   The V-ribbed belt according to claim 1, wherein the compressed rubber layer contains 10 to 40 parts by weight of reinforcing short fibers in a total addition amount with respect to 100 parts by weight of rubber. The V-ribbed belt according to claim 1, wherein the stretched rubber layer contains 0 to 30 parts by weight of a total amount of reinforcing short fibers with respect to 100 parts by weight of rubber.

Images