JP2022070718A - Transmission belt - Google Patents

Abstract

To provide a transmission bolt which is high in transmission capability, and excellent in gear change responsiveness.SOLUTION: A transmission belt B is formed of a rubber composition at a power transmission part of a V-side face 11a. In the rubber composition, a storage Young's modulus E'L of compression when the load vibration of compression stress between 0.25 MPa and 0.5 MPa is imparted at a frequency of 10 Hz under a temperature of 100°C in a belt width direction is equal to or lower than 220 MPa, and the E'H of compression when the load vibration of compression stress between 1.0 MPa and 2.0 MPa is imparted at a frequency of 10 Hz under a temperature of 100°C is equal to or higher than 220 MPa.SELECTED DRAWING: Figure 1A

Description

The present invention relates to a transmission belt.

Transmission belts whose V side surface is formed of a rubber composition are known. For example, Patent Document 1 discloses a transmission belt whose V side surface is formed of a rubber composition in which cellulose nanofibers and carbon black are dispersed in a rubber component.

Japanese Patent No. 6271823

An object of the present invention is to provide a transmission belt having high transmission ability and excellent shift response.

The present invention is a transmission belt in which the power transmission portion on the V side surface is formed of a rubber composition, and the rubber composition is 0.25 MPa and 0.5 MPa at a temperature of 100 ° C. in the belt width direction. When the load vibration of the compressive stress between is applied at a frequency of 10 Hz, the stored elastic modulus _E'L of the compression is 220 MPa or less, and at a temperature of 100 ° C., 1.0 MPa and 2.0 MPa. When the load vibration of the compressive stress during is applied at a frequency of 10 Hz, the stored elastic modulus _E'H of the compression is 220 MPa or more.

According to the present invention, the compressed storage elastic modulus _E'L of the rubber composition forming the power transmission portion on the V side surface is 220 MPa or less, and the compressed stored elastic modulus _E'H is 220 MPa or more. Therefore, it is possible to obtain excellent shift responsiveness as well as high transmission ability.

It is a perspective view of a piece of a double cogged V belt which concerns on embodiment. It is sectional drawing along the belt width direction of the double cogged V belt which concerns on embodiment. It is sectional drawing along the belt length direction of the double cogged V belt which concerns on embodiment. It is a perspective view of the test piece for measuring the stored elastic modulus _E'L , _E'H of compression. It is a front view which shows the pulley layout of the belt running tester for measuring the transmission ability. It is a front view which shows the pulley layout of the belt running tester for durability evaluation.

Hereinafter, embodiments will be described in detail.

1A to 1C show a double cogged V-belt B (transmission belt) according to an embodiment. The double cogged V-belt B according to the embodiment is a power transmission member used as a speed change belt in, for example, a speed change device of a two-wheeled vehicle. The double cogged V-belt B according to the embodiment has, for example, a belt length of 700 mm or more and 1400 mm or less, a maximum belt width of 16 mm or more and 40 mm or less, and a maximum belt thickness of 8.0 mm or more and 18.0 mm or less.

The double cogged V-belt B according to the embodiment includes an endless rubber belt body 11. The belt main body 11 is formed in a shape in which a cross-sectional shape along the belt width direction is combined so that an isosceles trapezoid on the inner peripheral side of the belt and a horizontally long rectangular shape on the outer peripheral side of the belt are laminated. The angle formed by the V side surfaces 11a on both sides of the belt body 11 is, for example, 24 ° or more and 36 ° or less. The belt main body 11 is composed of three layers: a compressed rubber layer 111 on the inner peripheral side of the belt, an adhesive rubber layer 112 at an intermediate portion in the belt thickness direction, and an stretch rubber layer 113 on the outer peripheral side of the belt. The V side surfaces 11a on both sides of the belt body 11 are composed of both side surfaces of the compressed rubber layer 111 and the adhesive rubber layer 112, and a part of both side surfaces of the stretch rubber layer 113 on the inner peripheral side of the belt. The side surface of the compressed rubber layer 111 occupies the largest proportion of the V side surface 11a, which constitutes the power transmission unit.

The double cogged V-belt B according to the embodiment includes a covering cloth 12 provided so as to cover the surface of the compressed rubber layer 111 on the inner peripheral side of the belt. On the inner circumference of the compressed rubber layer 111, lower cog forming portions 111a having a sine-curved cross-sectional shape along the belt length direction are arranged at a constant pitch. Then, the lower cog forming portion 111a is covered with the covering cloth 12 to form the lower cog 13. The double cogged V-belt B according to the embodiment includes a core wire 14 embedded in an intermediate portion of the adhesive rubber layer 112 in the belt thickness direction. The core line 14 is provided so as to form a spiral having a pitch in the belt width direction along the circumferential direction. On the outer periphery of the stretch rubber layer 113, upper cogs 15 having a rectangular cross-sectional shape along the belt length direction are arranged at a constant pitch.

The compressed rubber layer 111 is formed of the rubber composition A. The rubber composition A forming the compressed rubber layer 111 is an uncrosslinked rubber composition obtained by blending various rubber compounding agents with a rubber component and kneading the rubber component by heating and pressurizing. The rubber composition A is provided so that the columnar direction corresponds to the belt width direction and the anti-columnar direction corresponds to the belt length direction, respectively.

Examples of the rubber component of the rubber composition A include chloroprene rubber (CR); ethylene-propylene copolymer (EPR), ethylene-propylene-dienter polymer (EPDM), ethylene-octene copolymer, ethylene-butene copolymer and the like-. Examples thereof include α-olefin elastomer; chlorosulfonated polyethylene rubber (CSM); hydrogenated acrylonitrile rubber (H-NBR). The rubber component is preferably one of these rubbers or a blended rubber of two or more, and more preferably contains chloroprene rubber (CR) from the viewpoint of obtaining high transmission ability and excellent shift response. , Sulfur-modified chloroprene rubber (sulfur-modified CR) is more preferably contained.

The rubber composition A preferably contains cellulosic fine fibers dispersed in a rubber component as a rubber compounding agent from the viewpoint of obtaining high transmission ability and excellent shift response. Cellulose-based fine fibers are fiber materials derived from cellulosic fine fibers composed of skeletal components of plant cell walls obtained by finely loosening plant fibers. Examples of raw material plants for cellulosic fine fibers include trees, bamboo, rice (rice straw), potatoes, sugar cane (bagasse), aquatic plants, seaweeds and the like. Of these, wood is preferred.

Examples of the cellulosic fine fiber include the cellulose fine fiber itself and the hydrophobic cellulose fine fiber obtained by hydrophobizing the cellulose fine fiber itself. Cellulose-based fine fibers preferably contain one or both of these.

Examples of the cellulosic fine fiber include those having a high aspect ratio produced by mechanical defibration means and those having needle-like crystals produced by chemical defibration means. The cellulosic fine fibers preferably contain one or both of them, and may contain cellulosic fine fibers produced by mechanical defibration means from the viewpoint of obtaining high transmission ability and excellent shift response. More preferred.

The average fiber diameter of the cellulosic fine fibers is, for example, 10 nm or more and 1000 nm or less. The average fiber length of the cellulosic fine fibers is, for example, 0.1 μm or more and 1000 μm or less. The content of the cellulosic fine fibers in the rubber composition A is preferably 1 part by mass or more and 10 parts by mass or less, more preferably 1 part by mass or less, with respect to 100 parts by mass of the rubber component, from the viewpoint of obtaining high transmission ability and excellent shift response. Is 1.5 parts by mass or more and 5 parts by mass or less, more preferably 2 parts by mass or more and 3 parts by mass or less.

The rubber composition A preferably contains carbon black dispersed in a rubber component as a rubber compounding agent from the viewpoint of obtaining high transmission ability and excellent shift response. Examples of carbon black include channel black; furnace black such as SAF, ISAF, N-339, HAF, N-351, MAF, FEF, SRF, GPF, ECF, and N-234; thermal black such as FT and MT; Examples include acetylene black. The carbon black preferably contains one or more of these, and more preferably contains carbon black having an arithmetic mean particle size of 50 μm or less from the viewpoint of obtaining high transmission ability and excellent shift response. , FEF is more preferably included.

The content of carbon black in the rubber composition A is preferably 30 parts by mass or more and 70 parts by mass or less, more preferably 36 parts by mass with respect to 100 parts by mass of the rubber component, from the viewpoint of obtaining high transmission ability and excellent shift response. It is 5 parts by mass or more and 59 parts by mass or less, more preferably 41 parts by mass or more and 49 parts by mass or less.

When the rubber composition A contains cellulosic fine fibers and carbon black, the content of carbon black in the rubber composition A is the content of the cellulosic fine fibers from the viewpoint of obtaining high transmission ability and excellent shift response. Preferably more than. The ratio of the carbon black content to the cellulosic fine fiber content in the rubber composition A (carbon black content / cellulosic fine fiber content) is preferably 10 or more and 30 or less from the same viewpoint. It is preferably 15 or more and 23 or less, and more preferably 17 or more and 19 or less.

The rubber composition A contains, as a rubber compounding agent, short fibers dispersed in the rubber component so as to be oriented in the columnar direction and therefore, in the belt width direction, from the viewpoint of obtaining high transmission ability and excellent shift response. Is preferable. It is preferable that the short fibers are subjected to an adhesive treatment such as an RFL treatment for imparting adhesiveness to the compressed rubber layer 111 of the belt body 11.

Examples of the staples include para-aramid staples (polyparaphenylene terephthalamide staples, copolyparaphenylene-3,4'-oxydiphenylene terephthalamide staples), meta-aramid staples, nylon 66 staples, and the like. Examples include polyester staples, polyvinyl alcohol staples, heterocyclic-containing aromatic staples, ultrahigh molecular weight polyolefin staples, polyparaphenylene benzobisoxazole staples, polyallylate staples, cotton, glass staples, carbon staples, etc. Will be. The short fibers preferably contain one or more of these, and preferably contain para-aramid short fibers from the viewpoint of obtaining high transmission ability and excellent shift response, and are preferably copolyparaphenylene-3. , 4'-oxydiphenylene terephthalamide staples are more preferred.

The fiber length of the staple fibers is preferably 1 mm or more and 5 mm or less, more preferably 2 mm or more and 4 mm or less, from the viewpoint of obtaining high transmission ability and excellent shift response. From the same viewpoint, the fiber diameter of the staple fibers is preferably 5 μm or more and 30 μm or less, and more preferably 10 μm or more and 15 μm or less.

The content of the staple fibers in the rubber composition A is preferably 20 parts by mass or more and 40 parts by mass or less, more preferably 23 parts by mass with respect to 100 parts by mass of the rubber component, from the viewpoint of obtaining high transmission ability and excellent shift response. It is 5 parts by mass or more and 37 parts by mass or less, more preferably 25 parts by mass or more and 34 parts by mass or less.

When the rubber composition A contains cellulosic fine fibers and short fibers, the content of the short fibers in the rubber composition A is the content of the cellulosic fine fibers from the viewpoint of obtaining high transmission ability and excellent shift response. Preferably more than. From the same viewpoint, the ratio of the content of the short fibers in the rubber composition A to the content of the cellulosic fine fibers (content of the short fibers / content of the cellulosic fine fibers) is preferably 7 or more and 17 or less. It is preferably 9 or more and 15 or less, and more preferably 11 or more and 13 or less.

When the rubber composition A contains carbon black and staple fibers, the content of the staple fibers in the rubber composition A should be less than the content of carbon black from the viewpoint of obtaining high transmission ability and excellent shift response. Is preferable. From the same viewpoint, the ratio of the staple fiber content to the carbon black content (staple content / carbon black content) in the rubber composition A is preferably 0.35 or more and 1.0 or less. It is preferably 0.45 or more and 0.79 or less, and more preferably 0.55 or more and 0.75 or less. From the same viewpoint, the sum of the contents of carbon black and staple fibers in the rubber composition A is preferably 50 parts by mass or more and 90 parts by mass or less, and more preferably 60 parts by mass or more and 79 parts by mass with respect to 100 parts by mass of the rubber component. It is 5 parts by mass or less, more preferably 65 parts by mass or more and 74 parts by mass or less.

The rubber composition A may contain a cross-linking agent, an anti-aging agent, a plasticizer, a processing aid, a co-crosslinking agent, a vulcanization accelerator, a vulcanization accelerator, and the like as other rubber compounding agents.

The tensile strength of the rubber composition A in the column direction at a temperature of 25 ° C. is preferably 40 MPa or more, more preferably 46 MPa or more, still more preferably 48 MPa, from the viewpoint of obtaining high transmission ability and excellent shift response. That is all. From the same viewpoint, the elongation at the time of cutting of the rubber composition A at a temperature of 25 ° C. is preferably 50% or more, more preferably 64% or more, still more preferably 66% or more. These tensile strengths and elongation at break are measured based on JISK6251: 2010.

The rubber composition A is subjected to a load vibration of a compressive stress between 0.25 MPa and 0.5 MPa at a frequency of 10 Hz in the columnar direction, that is, in the belt width direction at a temperature of 100 ° C. The stored elastic modulus _E'L of the compression is 220 MPa or less, and is preferably 165 MPa or more and 213 MPa or less, more preferably 192 MPa or more and 210 MPa or less, still more preferably 196 MPa, from the viewpoint of obtaining high transmission capacity and excellent shift response. It is 207 MPa or less.

The rubber composition A is subjected to a load vibration of a compressive stress between 1.0 MPa and 2.0 MPa at a frequency of 10 Hz in the columnar direction, that is, in the belt width direction at a temperature of 100 ° C. The stored elastic modulus _E'H of the compression is 220 MPa or more, and from the viewpoint of obtaining high transmission capacity and excellent shift response, it is preferably 230 MPa or more and 260 MPa or less, more preferably 232 MPa or more and 260 MPa or less, and further preferably 244 MPa. It is 256 MPa or less.

The ratio of the compression modulus _E'H to the compression modulus _E'L ( _E'H / _E'L ) is preferably from the viewpoint of obtaining high transmission capability and excellent shift response. It is 1.1 or more and 1.28 or less, more preferably 1.13 or more and 1.27 or less, and further preferably 1.22 or more and 1.25 or less.

Here, in the measurement of the stored elastic modulus _E'L , _E'H of these compressions, the thickness in the belt width direction is 10 mm from the double cogged V-belt B according to the embodiment, as shown in FIG. The belt piece cut out as described above is used as a test piece 20, the test piece 20 is set in a viscoelasticity measuring device, and the portion corresponding to the compressed rubber layer 111 is compressed in the belt width direction.

Similar to the compressed rubber layer 111, the adhesive rubber layer 112 and the stretched rubber layer 113 also have a rubber composition in which an uncrosslinked rubber composition obtained by blending various rubber compounding agents with a rubber component and kneaded is heated and pressed to crosslink. It is made of things. The rubber composition forming the adhesive rubber layer 112 and / or the stretchable rubber layer 113 may be the same as the rubber composition A forming the compressed rubber layer 111.

The covering cloth 12 is made of, for example, a woven cloth, a knitted fabric, a non-woven fabric, or the like made of threads such as cotton, polyamide fiber, polyester fiber, and aramid fiber. It is preferable that the covering cloth 12 is subjected to an adhesive treatment such as an RFL treatment for imparting adhesiveness to the compressed rubber layer 111.

The core wire 14 is composed of twisted yarns such as polyester fiber, polyethylene naphthalate fiber, aramid fiber, and vinylon fiber. It is preferable that the core wire 14 is subjected to an adhesive treatment such as an RFL treatment for imparting adhesiveness to the adhesive rubber layer 112.

According to the double-cogged V-belt B according to the embodiment of the above configuration, the compression storage elastic modulus _E'L of the rubber composition A forming the compressed rubber layer 111 constituting the power transmission portion of the V side surface 11a is 220 MPa. When the elastic modulus _E'H stored in compression is 220 MPa or more, high transmission ability and excellent shift response can be obtained. This is because the elastic modulus of the power transmission unit is increased in the high stress region and the transmission capacity is enhanced, but the elastic modulus is relatively low in the low stress region, and the damage of the shift response is impaired. Is presumed to be suppressed. Such an action effect is particularly effective in applications where a high torque and a high load are applied to the belt B, for example, in the case of a transmission of a large two-wheeled vehicle in which the minimum winding diameter of the belt B around the pulley is 70 mm or more. be.

The double cogged V-belt B according to the embodiment can be manufactured by a known method that has been generally used conventionally.

In the above embodiment, the double cogged V-belt B is used, but the present invention is not particularly limited to this, and a single cogged V-belt having a lower cog provided only on the inner peripheral side of the belt may be used. It may be a low-edge V-belt that is not provided. Further, the power transmission portion on the V side surface may be a V-ribbed belt formed of a rubber composition.

In the above embodiment, the configuration is provided with the covering cloth 12 that covers the surface on the inner peripheral side of the belt, but the present invention is not particularly limited to this, and in addition to the covering cloth 12 that covers the surface on the inner peripheral side of the belt. Alternatively, instead of the covering cloth 12 that covers the surface on the inner peripheral side of the belt, a covering cloth that covers the surface on the outer peripheral side of the belt may be provided, or the inner peripheral side of the belt and the outer peripheral side of the belt may be provided. It may be configured without a covering cloth for covering the surface.

(Double cogged V-belt)
The following double cogged V-belts of Examples 1 to 6 and Comparative Examples 1 to 4 were produced. The composition of the rubber composition forming each compressed rubber layer is also shown in Table 1.

<Example 1>
A composite material (manufactured by Toso Co., Ltd.) containing 2.5 parts by mass of cellulose-based fine fibers (average fiber diameter: 1000 nm or less) with respect to 100 parts by mass of sulfur-modified CR is used as an internal mixer in the sulfur-modified CR of the rubber component. Add and knead, and there, with respect to 100 parts by mass of sulfur-modified CR, 40 parts by mass of carbon black (Siest SO (FEF) Tokai Carbon Co., Ltd. arithmetic average particle size: 43 μm), 5 parts by mass of magnesium oxide, 2 .3 parts by mass of anti-aging agent (Nocrack AD-F: 2 parts by mass, Nocrack 8C-N: 0.3 parts by mass manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.) 5 parts by mass of plasticizer (DOS Taoka Kagaku Kogyo Co., Ltd.) ), 1 part by mass of processing aid (stearic acid), 5 parts by mass of co-crossing agent (Barnock PM (m-phenylenedi maleimide) manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.), and 10 parts by mass of zinc powder (UF powder). After adding (manufactured by Hakusui Tech) and kneading, they were divided and weighed. Next, the kneaded product was put into an internal mixer and kneaded, and then 5 parts by mass of zinc oxide and 30 parts by mass of RFL treatment were applied to 100 parts by mass of sulfur-modified CR to para-aramid staple fibers ( A non-crosslinked rubber composition was prepared by adding technola (copolyparaphenylene-3,4'-oxydiphenylene terephthalamide staple fiber) manufactured by Teijin Limited, fiber length: 3 mm, fiber diameter: 12 μm) and kneading.

Then, the uncrosslinked rubber composition was arranged and crosslinked so that the columnar direction corresponds to the belt width direction and the anti-columnar direction corresponds to the belt length direction, respectively, to form a compressed rubber layer. A double-cogged V-belt having the same configuration as that of the embodiment was produced and used as Example 1.

The adhesive rubber layer and the stretched rubber layer were formed of a rubber composition having a sulfur-modified CR as a rubber component. The covering cloth was composed of a polyester fiber woven cloth that had been subjected to RFL treatment and rubber glue treatment. The core wire was composed of twisted yarns of para-aramid fibers subjected to RFL treatment and rubber glue treatment. The belt size was 1200 mm for the belt length, 33 mm for the maximum belt width, and 16.0 mm for the maximum belt thickness.

<Example 2>
Same as Example 1 except that the contents of carbon black and para-aramid staple fibers in the rubber composition forming the compressed rubber layer were 45 parts by mass and 25 parts by mass with respect to 100 parts by mass of the sulfur-modified CR, respectively. A double-cogged V-belt having a configuration was produced, and this was designated as Example 2.

<Example 3>
Same as Example 1 except that the contents of carbon black and para-aramid staple fibers in the rubber composition forming the compressed rubber layer were 35 parts by mass and 35 parts by mass with respect to 100 parts by mass of the sulfur-modified CR, respectively. A double-cogged V-belt having a configuration was produced, and this was designated as Example 3.

<Example 4>
Same as Example 1 except that the contents of carbon black and para-aramid staple fibers in the rubber composition forming the compressed rubber layer were 50 parts by mass and 25 parts by mass with respect to 100 parts by mass of the sulfur-modified CR, respectively. A double-cogged V-belt having a configuration was produced, and this was designated as Example 4.

<Example 5>
Same as Example 1 except that the contents of carbon black and para-aramid staple fibers in the rubber composition forming the compressed rubber layer were 60 parts by mass and 25 parts by mass with respect to 100 parts by mass of the sulfur-modified CR, respectively. A double-cogged V-belt having a configuration was produced, and this was designated as Example 5.

<Example 6>
Same as Example 1 except that the contents of carbon black and para-aramid staple fibers in the rubber composition forming the compressed rubber layer were 50 parts by mass and 30 parts by mass with respect to 100 parts by mass of the sulfur-modified CR, respectively. A double-cogged V-belt having a configuration was produced, and this was designated as Example 6.

<Comparative Example 1>
A double-cogged V-belt having the same configuration as that of Example 4 was produced except that the rubber composition forming the compressed rubber layer did not contain cellulosic fine fibers, and this was designated as Comparative Example 1.

<Comparative Example 2>
The rubber composition forming the compressed rubber layer does not contain cellulosic fine fibers, and the contents of carbon black and para-aramid staple fibers are 35 parts by mass and 25 parts by mass with respect to 100 parts by mass of sulfur-modified CR, respectively. A double-cogged V-belt having the same configuration as that of Example 1 was produced except for the above, and it was designated as Comparative Example 2.

<Comparative Example 3>
The rubber composition forming the compressed rubber layer does not contain cellulosic fine fibers, and the contents of carbon black and para-aramid staple fibers are 45 parts by mass and 35 parts by mass with respect to 100 parts by mass of sulfur-modified CR, respectively. A double-cogged V-belt having the same configuration as that of Example 1 was produced except for the above, and it was designated as Comparative Example 3.

<Comparative Example 4>
Same as Example 1 except that the contents of carbon black and para-aramid staple fibers in the rubber composition forming the compressed rubber layer were 45 parts by mass and 30 parts by mass with respect to 100 parts by mass of the sulfur-modified CR, respectively. A double-cogged V-belt having a configuration was produced, and this was used as Comparative Example 4.

(Test method)
<Rubber member tensile properties>
The uncrosslinked rubber sheet of the uncrosslinked rubber composition used for forming the compressed rubber layer of each of the double cogged V-belts of Examples 1 to 6 and Comparative Examples 1 to 4 was press-molded to prepare a crosslinked rubber sheet. Then, a No. 3 dumbbell test piece was punched out from there, and the tensile strength in the columnar direction and the elongation at the time of cutting in the anti-columnar direction under a temperature of 25 ° C. were measured based on JISK6251: 2010.

<Rubber member compression characteristics>
For each of the double cogged V-belts of Examples 1 to 6 and Comparative Examples 1 to 4, a row in which para-aramid staple fibers are oriented from the uncrosslinked rubber sheet of the uncrosslinked rubber composition used to form the compressed rubber layer. A strip-shaped rubber is cut out so that the rational direction is the width direction, and the rolled-up rubber is press-molded to compress the para-aramid staple fibers into a disk shape with a diameter of 29 mm and a thickness of 12.5 mm. A test piece for test was prepared. Then, the test piece for compression test is set in a viscoelasticity measuring device so that the thickness direction is the compression direction, and a load of compressive stress between 0.25 MPa and 0.5 MPa is applied at a temperature of 100 ° C. Vibration was applied at a frequency of 10 Hz, and the stored elastic modulus _E'L of the compression at that time was measured. Further, the stored elastic modulus _E'H of the compression was measured when the load vibration of the compressive stress between 1.0 MPa and 2.0 MPa was applied at a frequency of 10 Hz at a temperature of 100 ° C.

<Belt compression characteristics>
As shown in FIG. 2, for each of the double-cogged V-belts of Examples 1 to 6 and Comparative Examples 1 to 4, a belt piece having a length of 50 mm was cut out so that the thickness in the belt width direction was 10 mm. Then, the belt piece is set as a test piece 20 in a viscoelasticity measuring device so that the belt width direction is the compression direction, and the portion corresponding to the compression rubber layer is set to 0.25 MPa and 0 at a temperature of 100 ° C. A load vibration of compressive stress between .5 MPa was applied at a frequency of 10 Hz, and the stored elastic modulus _E'L of the compression at that time was measured. Further, the stored elastic modulus _E'H of the compression was measured when the load vibration of the compressive stress between 1.0 MPa and 2.0 MPa was applied at a frequency of 10 Hz at a temperature of 100 ° C.

<Transmission ability>
FIG. 3 shows a belt running tester 30 for measuring transmission ability. The belt traveling tester 30 for measuring the transmission capacity includes a drive pulley 31 having a pulley diameter of 111 mm and a driven pulley 32 having a pulley diameter of 111 mm provided on the side thereof.

A state in which the double cogged V-belts B of Examples 1 to 6 and Comparative Examples 1 to 4 are wound between the drive pulley 31 and the driven pulley 32 and an axial load DW (dead weight) is applied so as to generate belt tension. Then, the drive pulley 31 was rotated at 1800 rpm to run the belt, and the rotational load of the driven pulley 32 was increased to calculate the transmission torque when the apparent slip ratio was 2.5%. Then, this belt running test was carried out by gradually increasing the axial load DW on the driven pulley 32 from 1470N to a maximum of 2744N, and the maximum value of the transmission torque obtained therein was obtained. The transmission ability was set as a relative value when the maximum value of each transmission torque was set to 100 as the maximum value of the transmission torque of Comparative Example 1.

<Shift response>
The double cogged V-belts of Examples 1 to 6 and Comparative Examples 1 to 4 are wound around the drive pulley and the driven pulley of the transmission of the two-wheeled vehicle for testing and mounted on the actual machine, and the drive pulley and the driven pulley are operated by operating the engine. The belt was run between the pulleys. While the engine is rotating at full throttle, the internal centrifugal roller increases the belt winding diameter on the drive pulley by applying a pressing force so as to narrow the gap between the grooves of the drive pulley as the rotation speed increases. At the same time, the speed was increased by reducing the belt winding diameter on the driven pulley and shifting the speed by the action of a force that opposes the pressing force of the spring that widens the gap between the grooves of the driven pulley. Regarding the shift response, the case where the rotation speed of the driven pulley exceeds 2000 rpm when the rotation speed of the drive pulley is 4000 rpm is evaluated as A (excellent), and the case where the rotation speed is 2000 rpm or less is evaluated as B (poor).

<Durability>
FIG. 4 shows a belt running tester 40 for durability evaluation. The belt running tester 40 for durability evaluation includes a drive pulley 41 having a pulley diameter of 200 mm and a driven pulley 42 having a pulley diameter of 140 mm provided on the side thereof.

The double cogged V-belts B of Examples 1 to 6 and Comparative Examples 1 to 4 are wound between the drive pulley 41 and the driven pulley 42, and the shaft load DW (dead) of 1800 N is generated on the driven pulley 42 so as to generate belt tension. The weight) was loaded, and the drive pulley 41 was rotated at 4800 rpm to run the belt under a rotational load of 30 Nm. Then, the traveling time until the double cogged V-belt B was damaged was measured. The durability was taken as a relative value when the traveling time of Comparative Example 1 was set to 100.

(Test results)
The test results are shown in Table 2. According to Table 2, in Examples 1 to 6 in which _E'L is 220 MPa or less and _E'H is 220 MPa or more, the shift response is excellent and the transmission ability is higher than that of the standard Comparative Example 1. You can see that. On the other hand, in Comparative Example 2 in which _E'L is 220 MPa or less but _E'H is 220 MPa or less, it can be seen that although the shift response is excellent, the transmission ability is only at the same level as in Comparative Example 1. On the contrary, in Comparative Examples 3 and 4 in which _E'H is 220 MPa or more but _E'L is 220 MPa or more, it can be seen that the transmission ability is high but the shift response is inferior.

The present invention is useful in the art of transmission belts.

B Double Cogged V Dobelt (Transmission Belt)
11 Belt body 11a V Side surface 111 Compressed rubber layer 111a Lower cog forming part 112 Adhesive rubber layer 113 Stretched rubber layer 12 Covering cloth 13 Lower cog 14 Core wire 15 Upper cog 20 Test piece 30, 40 Belt running tester 31, 41 Drive pulley 32,42 Driven pulley

Claims (8)

The power transmission part on the V side surface is a transmission belt made of a rubber composition.
The rubber composition has a compression storage elastic modulus when a load vibration of a compressive stress between 0.25 MPa and 0.5 MPa is applied at a frequency of 10 Hz at a temperature of 100 ° C. in the belt width direction. When the coefficient _E'L is 220 MPa or less and the load vibration of the compressive stress between 1.0 MPa and 2.0 MPa is applied at a frequency of 10 Hz at a temperature of 100 ° C., the stored elasticity of the compression is applied. A transmission belt having a coefficient _E'H of 220 MPa or more. In the transmission belt according to claim 1,
A transmission belt in which the ratio of the freshly stored elastic modulus _E'H of the compression to the freshly stored elastic modulus _E'L of the compression is 1.1 or more and 1.28 or less. In the transmission belt according to claim 1 or 2.
A transmission belt in which the rubber composition contains a rubber component. In the transmission belt according to claim 3,
A transmission belt in which the rubber component contains chloroprene rubber. In the transmission belt according to claim 3 or 4.
A transmission belt in which the rubber composition contains cellulosic fine fibers. In the transmission belt according to claim 5,
A transmission belt in which the content of the cellulosic fine fibers in the rubber composition is 1 part by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the rubber component. In the transmission belt according to any one of claims 3 to 6, the transmission belt
A transmission belt in which the rubber composition contains short fibers. In the transmission belt according to claim 7,
A transmission belt in which the content of the staple fibers in the rubber composition is 20 parts by mass or more with respect to 100 parts by mass of the rubber component.

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