JPH09303488A - Power transmitting v belt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a V belt which is excellent in resistance for side pressure and bending fatigue, heat resistance and abrasion resistance. SOLUTION: A power transmitting V belt 1 is composed of a tension layer 4 in which a core wire 3 is spirally embedded in an adhesion rubber 2 in a longitudinal direction of a belt, an extension rubber layer 5 superposed on an upper surface of the tension layer 4, and a compression rubber layer 6 which has a cog 7 laminated on a lower surface of the tension layer 4. At least the compression rubber layer 6 is composed of rubber component prepared by blending hydrogenated nitryl rubber, metallic salt of unsaturated carbonic acid, short fibers, and organic peroxide followed by bridging. A cracking preventive rubber layer 10 made of hydrogenerated nitryl rubber, metallic salt of unsaturated carbonic acid, and organic peroxide while including no short fibers is superposed on the compression rubber layer 6. The compression rubber layer 6 is preparred by adding organic peroxide of 0.2 to 10 parts by weight and short fibers of 5 to 40 parts by weight in respect to polymer component 100 parts by weight includding hydrogenated nitryl rubber and unsaturated carbonic acid metallic salt with the ratio of 98:2 to 55:45.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a V-belt for power transmission which is hung on a V-pulley and has particularly excellent bending fatigue resistance, lateral pressure resistance, heat resistance and wear resistance. V-belts for power transmission.

[0002]

2. Description of the Related Art In recent years, with the increase in engine output and rotation speed, the operating environment temperature of the power transmission V-belt has risen and the lateral pressure received from the V-pulley on the power transmission belt has also risen. The quality required for such a belt is that the lateral pressure resistance when driving the belt is high, the abrasion resistance is good, and the flex fatigue resistance is excellent.

Conventional V-belts for power transmission are mainly made of chloroprene rubber. However, this material is liable to be hardened in a high temperature atmosphere and cracks due to hardening occur early, and the lateral pressure rigidity is insufficient in a high temperature atmosphere. Due to this, the belt deforms so as to fall into the pulley and buckling deformation called dishing occurs and power cannot be transmitted, or peeling between the core wire and the adhesive rubber causes a failure such as pop-out and the belt. There was a problem of reaching the end of life.

In order to solve this problem, instead of chloroprene rubber, a hydrogenated nitrile rubber or a rubber composition in which an unsaturated carboxylic acid metal salt such as zinc methacrylate is mixed with an organic peroxide is used. This is disclosed in, for example, Japanese Patent Laid-Open No. 1-311158.

[0005]

A rubber composition obtained by mixing hydrogenated nitrile rubber with zinc methacrylate and an organic peroxide is reinforced by a chemical reaction with zinc methacrylate, and therefore carbon black, short fibers, etc. It has been said that the reinforcing material is unnecessary because the rubber strength is rather lowered depending on the amount added. For this reason, a rubber composition containing no reinforcing material such as carbon black or short fibers added to V-belts or V-belts.
Although it has been proposed to use it for a ribbed belt, when it is used for this kind of power transmission V-belt, especially for speed-changing V-belt which receives a large lateral pressure from a V-pulley, it does not satisfy lateral pressure resistance and bending fatigue resistance. Problem has occurred.

The present invention solves these problems, and provides a V-belt for power transmission which is excellent in lateral pressure resistance and bending fatigue resistance as well as heat resistance and abrasion resistance. To aim.

[0007]

In order to achieve such an object, the present invention provides a tensile member layer in which a core wire is embedded spirally in an adhesive rubber along a longitudinal direction of a belt, and the tensile member layer. In a power transmission V-belt composed of a stretched rubber layer laminated on the upper surface of a body layer and a compressed rubber layer having a cog portion laminated on the lower surface of the tensile body layer, at least the compressed rubber layer is made of unsaturated carboxylic rubber of unsaturated carboxylic rubber. A short fiber consisting of a rubber composition obtained by mixing acid metal salt, short fiber, and organic peroxide and cross-linking it, and further comprising hydrogenated nitrile rubber in the compressed rubber layer, unsaturated carboxylic acid metal salt, and organic peroxide. A V-belt for power transmission in which at least one rubber layer for preventing cracks is laminated that does not contain

Further, according to the present invention, a rubber composition in which a rubber layer for crack prevention is composed of hydrogenated nitrile rubber, unsaturated carboxylic acid metal salt and organic peroxide, and does not contain a reinforcing material of short fiber and carbon black. And a case where a rubber layer for crack prevention is laminated along the shape of the cog portion.

Further, the compression rubber layer has a content of 0.2 to 100 parts by weight of a polymer composition in which hydrogenated nitrile rubber and unsaturated carboxylic acid metal salt are blended at 98: 2 to 55:45.
This also includes the case where a rubber composition obtained by adding 10 parts by weight of organic peroxide and 5 to 40 parts by weight of short fibers and blending the short fibers in the width direction of the belt to crosslink them is used.

[0010]

According to the present invention, at least the compression rubber layer uses a rubber composition in which a hydrogenated nitrile rubber is blended with unsaturated carboxylic acid metal salt, short fiber, and organic peroxide to crosslink, and thus lateral pressure resistance is improved. Excellent in heat resistance and wear resistance,
Furthermore, by laminating at least one rubber layer which is composed of hydrogenated nitrile rubber, unsaturated carboxylic acid metal salt, and organic peroxide and does not contain short fibers on the compression rubber layer, the belt bottom surface is bent at the time of reverse bending of the belt. Propagation of a crack that has occurred can be prevented, and bending fatigue resistance can be improved.

[0011]

1 is a cross-sectional perspective view of a main portion of a low edge cog belt which is an example of a V belt for power transmission according to the present invention. The power transmission V-belt 1 of the present invention includes an adhesive rubber 2
A tensile body layer 4 in which a core wire 3 is embedded in a spiral shape along the longitudinal direction of the belt, an expanded rubber layer 5 attached to the upper side of the tensile body layer 4, and an upper side of the tensile body layer 4. And a compressed rubber layer 6 attached to the.

As the core wire 3, a rope having a low elongation and a high strength is used, and an organic fiber such as aramid fiber, polyamide fiber or polyester fiber, or a twisted rope made of inorganic fiber such as glass fiber or metal fiber is used. Can be mentioned. The core wire 3 is strongly bonded to the adhesive rubber 2 by generally treating with resorcin-formalin-latex. Further, those having rubber glue or the like further attached to the surface treated with resorcin-formalin-latex are also used.

Next, the rubber composition for forming the compressed rubber layer 6 is a mixture of unsaturated carboxylic acid metal salt, short fibers, and organic peroxide, which are crosslinked. By blending an unsaturated carboxylic acid metal salt with hydrogenated nitrile rubber having good heat resistance, a rubber composition having excellent heat resistance, high strength and abrasion resistance can be obtained.

The hydrogenated nitrile rubber used in the present invention is not particularly limited, but the Mooney viscosity (M
It is preferable that L1 + 4 (100 ° C.)) is 70 to 85 in order to improve mechanical strength and lateral pressure rigidity, and also to improve flexibility and workability.

The unsaturated carboxylic acid metal salt is an ionic bond between an unsaturated carboxylic acid having a carboxyl group and a metal. Examples of the unsaturated carboxylic acid include monocarboxylic acids such as acrylic acid and methacrylic acid, maleic acid and fumaric acid. acid,
Dicarboxylic acids such as itaconic acid are preferable, and the metal includes beryllium, magnesium, calcium, strontium, barium, titanium, chromium, molybdenum, manganese, iron, cobalt, nickel, copper, silver, zinc, cadmium, aluminum, tin, lead. , Antimony, etc. can be used.

The composition ratio of the hydrogenated nitrile rubber and the unsaturated carboxylic acid metal salt is 98: 2 to 55:45. If the hydrogenated nitrile rubber exceeds 98, the abrasion resistance will be insufficient, and if it is less than 55, the abrasion resistance will be good, but the flexibility of the belt will deteriorate, which is not preferable.

The organic peroxide is used as a cross-linking agent and includes di-t-butyl peroxide, dicumyl peroxide, t-butyl cumyl peroxide,
1.1-t-butylperoxy-3.3.5 trimethylcyclohexane, 2.5-di-methyl-2.5-di (t-
Butyl peroxy) hexane, 2.5-di-methyl-2.
5-di (t-butylperoxy) hexane-3, bis (t
-Butylperoxydi-isopropyl)) benzene, 2.
5-di-methyl-2.5-di (benzoylperoxy) hexane, t-butylperoxybenzoate, t-butylperoxy-2-ethyl-hexyl carbonate and the like are used. And as the compounding amount thereof, the rubber composition 10
0.2 to 10 parts by weight with respect to 0 parts by weight. This is because if it is less than 0.2 parts by weight, sufficient crosslinking cannot be carried out, and if it exceeds 10 parts by weight, sufficient elasticity cannot be obtained.

In the present invention, the hydrogenated nitrile rubber is blended in advance with a masterbatch in which the unsaturated carboxylic acid metal salt is dispersed, and the hydrogenated nitrile rubber is blended, and short fibers and an organic peroxide are added and crosslinked. It is also possible to use. In that case, the unsaturated carboxylic acid metal salt is contained in an amount of 10 to 100 relative to 100 parts by weight of the hydrogenated nitrile rubber.
A mixture of the dispersion in the range of parts by weight and the hydrogenated nitrile rubber alone in a ratio of 20:80 to 90:10 is used.

When the amount of unsaturated carboxylic acid metal salt is less than 10 parts by weight, the reinforcing effect by the chemical reaction is small and the abrasion resistance is insufficient, and when it exceeds 100 parts by weight, the abrasion resistance is improved. It is not preferable because the bending fatigue property deteriorates. Further, when the unsaturated carboxylic acid metal salt finely dispersed in the hydrogenated nitrile rubber and the hydrogenated nitrile rubber alone are blended in the above ratio, the unsaturated carboxylic acid metal salt is dispersed in the hydrogenated nitrile rubber. If the content is less than 20 parts by weight, the expected wear resistance and lateral pressure rigidity cannot be obtained. Further, if it exceeds 90 parts by weight, the flexibility is deteriorated.

By orienting the short fibers 7 used in the width direction of the belt, the lateral pressure resistance can be enhanced and the friction coefficient can be reduced. As the short fibers, cotton, polyester short fibers, polyamide short fibers, aramid short fibers and the like are used, and the mixing amount thereof is 5 to 40 parts by weight with respect to 100 parts by weight of the rubber composition. If it is less than 5 parts by weight, the effects of lateral pressure resistance and reduction of the friction coefficient are insufficient, and 4
If the amount exceeds 0 parts by weight, the problems that the kneading of the rubber becomes difficult and the bending fatigue resistance and heat resistant running life of the belt are shortened are not preferable.

Further, the short fibers can be firmly adhered to the rubber by subjecting them to an adhesive treatment in advance, so that a belt having a longer life can be obtained. In order to bond the hydrogenated nitrile rubber containing the unsaturated carboxylic acid metal salt used in the compressed rubber layer 6 of the belt in the present invention, the following adhesion treatment is preferably performed.

As the adhesion treatment, first, short fibers are dipped in an epoxy type treatment liquid and heated and dried, and then a mixed liquid of resorcin, formalin and rubber latex (RFL treatment liquid).
And heat-treat. The epoxy-based treatment liquid is a water-soluble epoxy resin-based treatment liquid, and specific examples thereof include NBR010A manufactured by DuPont.

The RFL treatment liquid used has a molar ratio of resorcin and formalin in the range of 1: 2 to 2: 1, and the ratio of solid rubber latex, solid resorcin and formalin is 1: 1 to 1: 1. A range of 10 is used. As the rubber latex, acrylonitrile-butadiene copolymer rubber latex, carboxylated acrylonitrile-butadiene copolymer rubber latex, styrene-butadiene copolymer rubber latex, vinylpyridine rubber latex, chlorosulfonated polyethylene rubber latex, etc. are used. However, it is particularly preferable to use an acrylonitrile-butadiene copolymer rubber latex.

In addition, the rubber of the compressed rubber layer 6 may include a reinforcing agent such as carbon black and silica, calcium carbonate,
Filler, cross-linking aid to improve wear resistance of talc, etc.
Various commonly used additives such as vulcanization accelerators, plasticizers, stabilizers, processing aids, antioxidants, and colorants may be blended according to the intended purpose. Further, a method of mixing rubber and various additives is usually used, and for example, a method of kneading using a Banbury mixer or a kneader can be mentioned.

As the adhesive rubber 2, hydrogenated nitrile rubber having unsaturated carboxylic acid metal salt dispersed therein, hydrogenated nitrile rubber, chlorosulfonated polyethylene, natural rubber, chloroprene rubber, styrene-butadiene rubber, butadiene rubber are used. And the like, or a single material thereof or a blend thereof. Further, as an example of the rubber used for the stretched rubber layer 5 laminated and adhered to the upper surface of the tensile body layer 4, the same kind of rubber as the adhesive rubber 2 can be cited.

Although only examples of the rubber used for the adhesive rubber 2 and the stretched rubber layer 5 are given, it goes without saying that the vulcanized or crosslinked rubber constitutes the finished product of the belt, such as carbon black and silica which are usually used. Reinforcements and calcium carbonate,
Fillers such as talc, crosslinking aids, vulcanization accelerators, plasticizers,
It contains various additives such as stabilizers, processing aids, anti-aging agents and colorants.

In the present invention, a belt having a high strength and a long life is obtained by using, in the compression rubber layer 6, hydrogenated nitrile rubber in which an unsaturated carboxylic acid metal salt is mixed and crosslinked with an organic peroxide. However, the strength of the entire belt can be improved by using the hydrogenated nitrile rubber containing the same unsaturated carboxylic acid metal salt not only for the compressed rubber layer 6 but also for the adhesive rubber 2. However, in the case of the adhesive rubber 2, if the adhesive force with the core wire 3 is not sufficient, the rubber and the core wire are easily separated, and a problem such as pop-out occurs. The rubber in which the unsaturated carboxylic acid metal salt is finely dispersed in the hydrogenated nitrile rubber has a poor adhesion to the core wire, so that the pop-out phenomenon easily occurs as it is.

Therefore, by adding silica, it is possible to obtain a belt having a sufficient adhesive force between the rubber and the core wire.
In order to impart appropriate adhesive strength, a rubber composition 100 comprising hydrogenated nitrile rubber and unsaturated carboxylic acid metal salt
Silica is blended in the range of 5 to 50 parts by weight with respect to parts by weight. If it is less than 5 parts by weight, sufficient adhesive force cannot be obtained,
If the amount exceeds 50 parts by weight, the viscosity is high in the uncrosslinked state, the processability is deteriorated, and the hardness after crosslinking becomes unnecessarily high, so that cracks are likely to occur, which is not preferable.

The organic peroxide used for rubber cross-linking is easily influenced by pH and easily causes ionic decomposition in an acidic atmosphere. Therefore, magnesium oxide, triethanolamine, diphenylguanidine, hexamethylenetetramine, etc. are used for pH adjustment. You may add the basic substance of. The addition amount varies depending on the type, but is about 0.5 to 10 parts by weight with respect to 100 parts by weight of the rubber composition comprising the hydrogenated nitrile rubber and the unsaturated carboxylic acid metal salt. If it is less than 0.5 parts by weight, the effect of pH adjustment is thin, and if it exceeds 10 parts by weight, the viscosity is high in the uncrosslinked state and the workability is deteriorated as in the case of silica, and the hardness after crosslinking is too high. Therefore, cracks are likely to occur, which is not preferable. The above metal oxides such as magnesium oxide and zinc oxide can be blended for the purpose of increasing the hardness of the rubber, and are added in an amount of 0.5 to 10 parts by weight with respect to 100 parts by weight of the rubber composition.

Further, the rubber in which the unsaturated carboxylic acid metal salt is dispersed, which is used for the compressed rubber layer 6 in the above description, can be used for the stretched rubber layer 5 of the belt, if necessary, so that it is more abrasion resistant. It is possible to obtain a belt having excellent properties and lateral pressure rigidity.

In the present invention, however, as shown in FIG. 1, in the compressed rubber layer 6, the crack preventing rubber layer 10 is laminated inside the reinforcing cloth 8 along the shape of the cog portion 7. The rubber layer 10 for crack prevention comprises hydrogenated nitrile rubber, unsaturated carboxylic acid metal salt, and organic peroxide,
It is composed of short fibers or a crosslinked rubber composition containing no reinforcing material such as short fibers or carbon black. Of course, the same rubber composition as the adhesive rubber 2 may be used. The thickness of the rubber layer 10 is preferably 0.5 to 3 mm, 0.5 m
When it is less than m, it becomes difficult to prevent the propagation of cracks, while when it exceeds 3 mm, the lateral pressure resistance is deteriorated.

It is preferable that the crack preventing rubber layer 10 is laminated at a position where cracks are likely to occur when the belt is reversely bent, that is, at a position near the groove bottom portion 11 of the cog portion 7. For example, as shown in FIG. The core wire 3 located near the groove bottom 11
May be stacked in parallel with each other, or may be stacked in a wave shape at a position close to the groove bottom 11 as shown in FIG. The rubber layer 10 for crack prevention has high strength and is highly flexible, and since no foreign matter is mixed, the groove bottom portion 1 of the cog portion 7 is
It has the function of preventing the propagation of cracks generated from No. 1.

A suitable application for using the belt as described above is a low edge cog belt used as a speed change belt for driving in a high temperature atmosphere such as a snowmobile or a scooter. As the type of this low edge cog belt, one having a cog only on the compression rubber layer on the lower surface of the belt as shown in FIG. 1 and a double cog belt having a cog on the extension rubber layer on the upper surface of the belt to further improve the flexibility of the belt. It may be.

[0034]

EXAMPLES The effects of the present invention will be confirmed below with reference to more specific examples. Example 1, Comparative Examples 1-2 A low edge cog belt as shown in FIG. 1 was produced using the rubber composition of the compression rubber layer, the extension rubber layer, the adhesive rubber, and the crack preventing rubber layer shown in Table 1. In this example, the same rubber composition was used for the crack preventing rubber layer and the adhesive rubber.

The low-edge cog belt is produced by twisting 1,100 denier polyethylene terephthalate fiber as the core wire in the upside-down direction with the upper twist number of 11.4 times / 10 cm and the lower twist number of 21.0 times / 10 cm. 2x
An untreated cord having a total denier of 6,600 and a twisted structure of 3 was prepared.

Then, this untreated cord was pre-dipped with an isocyanate adhesive and then heated to about 170 to 180 ° C.
At 200-240 ° C after being dipped in RFL solution
Was stretched and heat-set to obtain a treated cord.

As a reinforcing cloth, a plain woven canvas using a spun cotton yarn was used. After immersing these canvases in the RFL solution, they were heat-treated at 150 ° C. for 2 minutes to obtain treated canvases. Then, apply the rubber composition to these treated canvas
Coaching to make a canvas with rubber.

The cog pad is formed by sequentially laminating a crack preventing rubber layer (thickness of about 1.5 mm), an unvulcanized rubber sheet of a compressed rubber layer and an unvulcanized rubber sheet of an adhesive rubber on one reinforcing cloth, Installed in a flat mold with parts and grooves alternately arranged, 80 °
By pressurizing with C, a cog pad having a cog portion formed thereon was formed.

After preparing these materials, a cog pad was wound around a mold with a concave portion, and further, a core wire, a flat stretched rubber layer, and a reinforcing cloth were sequentially wound around to form a molded body. Subsequently, the jacket was covered, the mold was placed in a vulcanizing can, and vulcanized to obtain a belt sleeve. The sleeve was cut into a V-shape by a cutter and finished into individual low edge cog belts.

The obtained low-edge cog belt has an upper width of 3
The length was 5.2 mm, the thickness was 14.5 mm, the length was 1120 mm, and the depth of the cog portion was 6.8 mm. The durability test of these belts was performed to evaluate the bending fatigue resistance. The results are also shown in Table 1.

This test is called an up / down endurance test. A drive shaft and a driven shaft are respectively equipped with speed change pulleys, and a low edge cog belt is hung between these speed change pulleys with a predetermined tension. Rotation speed of 0-6
Change to 000 rpm, and 0-40 at the same time for the driven shaft.
The load was set to fluctuate ps. The drive shaft side was turned ON and the maximum speed was changed to 6000 rpm in a few seconds, and then turned OFF and changed to 0 rpm in a few seconds, and this was repeated to evaluate the durability of the belt.

[0042]

[Table 1]

As is clear from Table 1, the power transmission V-belt of the present invention shows no crack generation and is excellent in bending fatigue resistance as compared with a belt not using the rubber layer for crack prevention. I understand.

[0044]

According to the present invention, at least the compression rubber layer is prepared by using a rubber composition in which hydrogenated nitrile rubber is blended with unsaturated carboxylic acid metal salt, short fiber, and organic peroxide to crosslink the rubber composition. It has excellent lateral pressure resistance, heat resistance, and abrasion resistance. Furthermore, at least one rubber layer made of hydrogenated nitrile rubber, unsaturated carboxylic acid metal salt, and organic peroxide, which does not contain short fibers, is laminated on the compression rubber layer. By doing so, even if a crack is generated from the bottom surface of the belt when the belt is reversely bent, its propagation can be prevented, and there is an excellent effect that the bending fatigue resistance is improved and the life is extended.

[Brief description of drawings]

FIG. 1 is a perspective sectional view of an essential part of a power transmission V-belt according to the present invention.

FIG. 2 is a cross-sectional view of another V-belt for power transmission of the present invention.

FIG. 3 is a cross-sectional view of yet another V-belt for power transmission of the present invention.

[Explanation of symbols]

 1 V-belt for power transmission 2 Adhesive rubber 3 Core wire 4 Tensile body layer 5 Extension rubber layer 6 Compressed rubber layer 7 Cog part 8 Reinforcement cloth 10 Crack prevention rubber layer 11 Groove bottom part

Front page continuation (72) Inventor Kouri Kanai 4-1-2-1, Hamazoe-dori, Nagata-ku, Kobe Mitsuboshi Belt Co., Ltd.

Claims (4)

[Claims] 1. A tensile body layer in which a core wire is embedded in a spiral shape in an adhesive rubber along a longitudinal direction of a belt, an expanded rubber layer laminated on an upper surface of the tensile body layer, and the tensile body layer. In a power transmission V-belt comprising a compressed rubber layer having a cog portion laminated on the lower surface, at least the compressed rubber layer is crosslinked by blending hydrogenated nitrile rubber with unsaturated carboxylic acid metal salt, short fiber, and organic peroxide. At least one or more crack-preventing rubber layers composed of a rubber composition, composed of a compressed rubber layer, hydrogenated nitrile rubber, unsaturated carboxylic acid metal salt, and organic peroxide, and containing no short fibers, are laminated. Characteristic power transmission V-belt. 2. The rubber layer for crack prevention comprises a hydrogenated nitrile rubber, an unsaturated carboxylic acid metal salt, and an organic peroxide, and a rubber composition containing no reinforcing material of short fibers and carbon black. 1. V-belt for power transmission according to 1. 3. The V belt for power transmission according to claim 1, wherein a crack preventing rubber layer is laminated along the shape of the cog portion. 4. The compression rubber layer is 0.2 to 10 relative to 100 parts by weight of a polymer composition in which hydrogenated nitrile rubber and unsaturated carboxylic acid metal salt are blended at 98: 2 to 55:45.
The V-belt for power transmission according to claim 1, which comprises a rubber composition obtained by adding 5 parts by weight of an organic peroxide and 5-40 parts by weight of a short fiber, and mixing the short fiber in the width direction of the belt to crosslink the rubber composition.