JPH10132034A - V belt for transmitting power - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a V belt for transmitting power which is improved in travelling life of the belt by reducing the belt slip rte and preventing cracks which could be produced in the compressed rubber layer in a reverse bending travelling. SOLUTION: In a V belt for transmitting power in which are disposed an adhesive rubber layer 2 in which is buried a core 3 composed of a cord, an expandable rubber layer 5 at the upper part of the adhesive rubber layer 2 and a compressive rubber layer 7 at the lower part of the adhesive rubber layer 2, and the circumference of the belt is covered with a cover canvas 4, as the core 3, a twisting which is formed by twisting polyester fiber groups the main component units of which are ehylene-2 and 6-naphthalate, and has an oveall denier of 8,000 to 40,000 is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power transmission V-belt, and more particularly, to a power belt having a reduced belt slip ratio, and a crack in a compressed rubber layer even when the belt is reversely bent to improve the running life of the belt. The present invention relates to a transmission V-belt.

[0002]

2. Description of the Related Art As a power transmission V-belt, there is a wrapped belt whose periphery is covered with a cover canvas. In this belt, a cord made of a cord with low elongation and high strength is embedded in an adhesive rubber layer, and a compression rubber layer is provided below the core wire and an extension rubber layer is provided above the belt. In particular, the above-mentioned belt used for the drive device of the farm equipment has heat resistance performance under higher temperature,
What has been desired is to improve the transmission performance without lowering the crack resistance.

[0003] For this reason, belts generally used for agricultural equipment and the like have also tended to impart heat resistance to the cover canvas, the core wire, and the rubber composition, which are the constituent members. For example, a V-belt having improved abrasion resistance at high temperatures using a canvas woven from a blended yarn of an organic fiber mainly composed of polymetaphenylene isophthalamide fiber (aramid fiber) and a cotton fiber as a cover canvas, has been developed. It is disclosed in Japanese Patent Publication No. Hei 5-37065. Further, as a rubber composition, a chloroprene rubber composition, a hydrogenated nitrile rubber composition, or the like is used for a compressed rubber layer.

[0004]

However, even in a belt in which a canvas woven with a blended yarn of aramid fiber and cotton fiber is used as a cover canvas for covering the periphery of the belt, the belt slip rate is high and the transmission performance is reduced. There was a problem to do. Further, even when a heat-resistant rubber composition was used for the compressed rubber layer, cracks were easily formed in the compressed rubber layer at an early stage when the belt was reversely run. Therefore, when the belt dry heat shrinkage stress is increased in order to increase the belt tension to reduce the slip ratio, the belt dry heat shrinkage ratio increases, and the problem that the belt length contracts with time increases.

As a countermeasure, a belt in which two layers of canvas are laminated below a compressed rubber layer has been proposed. However, if the belt is run in a normal direction, that is, a forward direction, the rigidity is increased.
When the belt is bent with a small pulley, heat is generated and the hardness of the rubber increases quickly, which causes the rubber to easily crack at an early stage and lowers the transmission efficiency. Furthermore, when laminating this canvas at the time of manufacture, care must be taken so that the canvas is not wrinkled, and the process is time-consuming, resulting in an increase in product cost.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has a low belt slip ratio, and is less likely to cause cracks in a compressed rubber layer even in reverse bending running, thereby improving the running life of a power transmission. It is intended to provide a V-belt.

[0007]

That is, according to the first aspect of the present invention, an adhesive rubber layer in which a cord made of a cord is embedded, an extension rubber layer above the adhesive rubber layer, and a compression rubber layer below the adhesive rubber layer. In a power transmission V-belt in which a rubber layer is provided and the periphery of the belt is further covered with a canvas, the total denier is obtained by twisting polyester fiber filaments whose main constituent unit is ethylene-2,6-naphthalate. In a power transmission V-belt using twisted yarns of several 8,000 to 40,000, a cord using a polyester fiber having ethylene-2,6-naphthalate as a main constituent unit does not require a high belt tension. Also, the belt slip ratio can be reduced.

In the invention according to claim 2 of the present application, since the belt for power transmission has a stress at 3% elongation of 3.0 g / denier or more, the slip ratio is reduced and the running life of the belt is extended. I do.

In the invention according to claim 3 of the present application, the upper rubber layer and the lower rubber layer are used for the compressed rubber layer, and the lower rubber layer is thinner than the upper rubber layer and more excellent in heat resistance than the upper rubber layer. Since the belt is made of a material, the belt easily bends in the reverse direction, so that it is difficult for the compression rubber layer to crack, and the running life of the belt can be improved.

In the invention of claim 4 of the present application, an upper rubber layer made of a chloroprene rubber composition and a lower rubber layer made of a hydrogenated nitrile rubber composition or a rubber composition of chlorosulfonated polyethylene are used for the compressed rubber layer. By the combination, the belt is more easily bent backwards, so that the compressed rubber layer is less likely to crack, and the running life of the belt can be improved.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings. FIG. 1 is a perspective view of a power transmission V-belt of the present invention. In this belt 1, a cord 3 made of a cord is embedded in an adhesive rubber layer.
An extension rubber layer 5 made of the same material as the adhesive rubber layer 2 is provided, and a compression rubber layer 7 is provided below the adhesive rubber layer 2. The entire belt is surrounded by a cover canvas 4.

The compressed rubber layer 7 is formed of two layers, an upper rubber layer 9 and a lower rubber layer 10. The lower rubber layer 10 is thinner than the upper rubber layer 9, and the lower rubber layer 9 has a belt forming layer. Among them, the rubber composition having the highest heat resistance is used. When the belt is running in reverse bending, the lower rubber layer 9
Is the area that is subjected to repeated deformation of stretching and shrinking in the longitudinal direction of the belt, but if this layer is used and a rubber composition with excellent heat resistance is used, the rubber hardness will not increase and rubber elasticity will be maintained for a long time Can be easily cracked. The lower rubber layer 10 has a thickness of 0.8 to 2.5.
If the thickness is less than 0.8 mm, the improvement in crack resistance of the compressed rubber layer 7 is small, and if it exceeds 2.5 mm, the crack resistance is improved, but the cost is increased.

For the upper rubber layer 9, a rubber composition composed of natural rubber, styrene-butadiene rubber, nitrile rubber, chloroprene rubber alone or a mixture thereof is used, while for the lower rubber layer 10, alkylated chlorosulfanated polyethylene is used. And a rubber composition such as a hydrogenated nitrile rubber, and a mixed polymer of a hydrogenated nitrile rubber and a metal salt of an unsaturated carboxylic acid.

The chlorosulfonated polyethylene has a chlorine content of 15 to 35% by weight, preferably 25 to 32% by weight.
And a chlorosulfonated low-density polyethylene having a sulfur content in the range of 0.5 to 2.5% by weight.

Hydrogenated nitrile rubber is a rubber obtained by hydrogenating an acrylonitrile-butadiene copolymer.
The hydrogenation rate is 80% or more, and preferably 90% or more in order to exhibit heat resistance and ozone resistance characteristics. A hydrogenated nitrile rubber having a hydrogenation rate of less than 80% has extremely low heat resistance and ozone resistance. In consideration of oil resistance and cold resistance, the amount of bound acrylonitrile is preferably in the range of 20 to 45%. The iodine value is 10 to 40 g / 100.
g.

The upper rubber layer 9 and the lower rubber layer 10 include
For example, aramid, nylon, polyester, vinylon,
Short fibers such as cotton may be added so as to be oriented in the belt width direction. Further, it is not necessary to separate the compressed rubber layer 7 into two layers, the upper rubber layer 9 and the lower rubber layer 10, and it may be one layer.

The core wire 3 has a total denier of 8,000 to 4,000 twisted polyester fiber filaments having ethylene-2,6-naphthalate as a main constituent unit.
40,000 glued cords are used. The number of twists of this cord is 3 to 20/10 cm, and the number of twists is 6 to 35/10 cm. Total denier is 8,
If it is less than 000, the modulus and strength of the cord will be too low, and if it exceeds 40,000, the belt will be too thick and the bending fatigue will be poor.

The ethylene-2,6-naphthalate used in the present invention is usually prepared by condensation polymerization of naphthalene-2,6-dicarboxylic acid or an ester-forming derivative thereof with ethylene glycol in the presence of a catalyst under appropriate conditions. To be synthesized. At this time, if one or more appropriate third components are added before the completion of the polymerization of ethylene-2,6-naphthalate, a copolymer polyester is synthesized.

First, the uncoated cord is impregnated into a tank containing a treatment liquid selected from an epoxy compound and an isocyanate compound and pre-dipped, and then (2) 160 to 200 °. C. Drying is performed by passing through a drying furnace set at a temperature of C for 30 to 600 seconds. (3) Subsequently, the substrate is immersed in a tank containing an adhesive liquid composed of an RFL liquid, and (4) 210
~ 30 ° C in the stretching heat setting processor set at 260 ° C
After passing for 600 seconds, it is stretched by -1 to 3% to obtain a stretched cord.

Examples of the epoxy compound include polyhydric alcohols such as ethylene glycol, glycerin and pentaerythritol, reaction products of polyalkylene glycols such as polyethylene glycol and halogen-containing epoxy compounds such as epichlorohydrin, resorcinol,
It is a reaction product with polyhydric phenols such as bis (4-hydroxyphenyl) dimethylmethane, phenol / formaldehyde resin, resorcin / formaldehyde resin, and halogen-containing epoxy compounds. This epoxy compound is used by being mixed with an organic solvent such as toluene and methyl ethyl ketone.

Examples of the isocyanate compound include 4,4'-diphenylmethane diisocyanate, toluene 2,4-diisocyanate, P-phenyl diisocyanate, and polyaryl polyisocyanate. This isocyanate compound is also used by being mixed with an organic solvent such as toluene and methyl ethyl ketone.

The RFL solution is obtained by mixing a latex with an initial condensate of resorcinol and formalin, and the latex used herein includes chloroprene, styrene / butadiene / vinylpyridine terpolymer, hydrogenated nitrile, NBR, etc. It is.

The power transmission V-belt using the above-mentioned core wire 3 has a stress (3% modulus) required for elongation of 3% or more of 3.0 g / denier, and if this is satisfied, the belt slip ratio is reduced. A small and long belt life can be obtained. If the 3% modulus is less than 3.0 g / denier, the belt tends to stretch easily, the belt tension is greatly reduced, and the slip ratio tends to increase.

The cover canvas 4 is a cloth woven in a plain weave, a twill weave, a satin weave, or the like using a yarn made of cotton, nylon, polyester, vinylon, and polyarylate fibers. After the cover canvas 4 is subjected to the RFL treatment, the rubber composition is subjected to fiction coating to obtain a canvas with rubber. The RFL solution is obtained by mixing a latex with an initial condensate of resorcinol and formalin. Latexes used herein include chloroprene, styrene-butadiene-vinylpyridine terpolymer, hydrogenated nitrile, NBR, and the like.

[0025]

EXAMPLES Hereinafter, the effects of the present invention will be confirmed by more specific experimental examples. Examples 1-3, Comparative Examples 1-2 As denier, 1,000 denier ethylene-2,6-
A polyester filament (PEN) having naphthalate as a main constituent unit and a 1,000-denier polyethylene terephthalate fiber (PET) are ply-twisted 9.0 times /
10 cm, the number of lower twists is 21.0 times / 10 cm, and the yarn is twisted in the upside down direction to form a 3 × 8 twisted structure.
4,000 or 26,400 raw codes were prepared. Table 1 shows the physical properties of these unprocessed codes.

[0026]

[Table 1]

Next, the untreated cord was pre-diped with 5% by weight of a polyisocyanate compound (PAPI-135: manufactured by MDK Kasei Co., Ltd.) using an isocyanate-based adhesive composed of 95% by weight of toluene, and then, about 170 to 18%.
After drying at 0 ° C. and dipping in RFL solution (100 parts by weight of CR latex, 14.6 parts by weight of resorcinol, 9.2 parts by weight of formalin, 1.5 parts by weight of caustic soda, 262.5 parts by weight of water), 200 A stretch heat setting treatment was performed at a temperature of up to 240 ° C. to obtain a treated code. Table 2 shows the physical properties of these processing codes.

[0028]

[Table 2]

As the cover canvas, a canvas was woven using cotton spun yarn, and a chloroprene rubber composition was frictionally applied to the canvas to obtain a canvas with rubber.

The wrapped V-belt (upper width: 16.5 mm, thickness: 8.0) was obtained by using the rubber composition of the compressed rubber layer shown in Table 3.
mm, length 1016 mm). This wrapped V
The method for manufacturing the belt is as follows. That is, thickness 4mm
After winding a rubber sheet corresponding to a compressed rubber layer obtained by laminating an upper rubber layer and a lower rubber layer having a thickness of 1.5 mm around a mantle, the core wire is spun, and a stretched rubber layer same as the upper rubber layer is formed thereon. Wind the corresponding rubber sheet. After cutting the belt of this molded body to a predetermined width, it is skived and then wrapped with a cover canvas. After the obtained belt was fitted into a ring mold, it was vulcanized to complete a wrapped V-belt. Table 4 shows the performance of the obtained wrapped V-belt.

[0031]

[Table 3]

The test method of the cord and the belt is as follows.

(1) Cord strength The cord strength was determined based on JIS L-1071 (1983).

(2) Cord dry heat shrinkage ratio 150 according to JIS L-1071 (1983)
The temperature was determined by standing at an ambient temperature of 30 ° C. for 30 minutes.

(3) Shrinkage stress of cord under dry heat An initial load of 0.25 g / d was applied, and the cord was allowed to stand in an atmosphere of 150 ° C. for 8 minutes.

(4) Stress at 3% Elongation of the Belt The belt was pulled at a speed of 50 mm / min, and
% Elongation was measured, and the stress was calculated by dividing the stress by the total denier of the cord.

(5) Belt slip ratio A driving pulley (diameter 195 mm) and a driven pulley (diameter 19)
5 mm), a belt was hung on a biaxial pulley, and a driven pulley (195 mm in diameter) was pulled at 210 kgf to apply tension to the belt. The running conditions were as follows: the ambient temperature was room temperature, the rotation speed of the driving pulley was 1800 rpm, and the load on the driven pulley (diameter 195 mm) was 23 ps. Using this running tester, the belt slip rate after running for 400 hours was calculated by the following equation: slip rate (%) = 100 × (I _O −I ₄₀₀ ) / I _O I _O = N _DN.0 / N _DR.0 I ₄₀₀ = N _DN.400 / N _DR.400 N _DR.0 : Drive pulley rotation speed (r at the start of test (no load)
pm) N _DN.0 : _Driven pulley rotation speed (r
pm) N _DR.400 : Drive pulley rotation speed after running for 400 hours (rpm)
m) N _DN.400 : _Driven pulley rotation speed after running for 400 hours (rpm
m)

(6) Belt Life Index A running test was conducted with the same layout as above, and the time until cracks occurred in the ribs of the belt was measured.
Is indicated by an index with 100 as the index.

[0039]

[Table 4]

As a result, it can be seen that the belt of the example has a stress at 3% elongation of 3 g / d or more, a small slip ratio, and an improved belt life as compared with the comparative example.

Example 4, Comparative Example 3 Using the rubber compound (upper rubber layer and lower rubber layer) of the compressed rubber layer shown in Table 5, the same cords and cover canvas as in Examples 1 to 3 were used. Wrapped V belt (upper width 16.5 mm, thickness 8.0 mm, length 1016 m)
m) was prepared. The slip ratio of the wrapped V-belt thus obtained and the running life of the belt in a reverse bending running test were measured. Table 6 shows the results.

In the belt reverse running test, the wrapped V-belt was hung on a driving pulley (diameter 90 mm) and a driven pulley (diameter 120 mm), and a tension pulley (diameter 60 mm) was brought into contact with the back of the belt. Then, the vehicle was driven under the conditions of a driving pulley rotation speed of 1,800 rpm and a load of 3.7 kW.

[0043]

[Table 5]

[0044]

[Table 6]

From Table 6, it can be seen that the belt of this example has a lower slip ratio than the comparative example, and has a longer time until cracks occur in the compressed rubber layer during reverse bending running, and is excellent in durability and cracking properties. It turns out that there is.

[0046]

As described above, according to the first aspect of the present invention, the adhesive rubber layer having the cords embedded therein is
In a power transmission V-belt in which an extension rubber layer is disposed above the adhesive rubber layer and a compression rubber layer is disposed below the adhesive rubber layer, and the periphery of the belt is covered with a cover canvas, the above-mentioned core wire is ethylene-
A power transmission V-belt using a twisted yarn having a total denier of 8,000 to 40,000, in which a polyester fiber filament group having 2,6-naphthalate as a main constituent unit is twisted, and ethylene-2,6-naphthalate is used. A cord using a polyester fiber as a main constituent unit has the effect of reducing the belt slip ratio without increasing the belt tension and improving the running life of the belt.

In the invention according to claim 2 of the present application, since the belt for power transmission has a stress at 3% elongation of 3.0 g / denier or more, the slip ratio is the same as in the invention according to claim 1. It becomes smaller and extends the running life of the belt.

In the invention according to claim 3 of the present application, the upper rubber layer and the lower rubber layer are used for the compressed rubber layer, and the lower rubber layer is thinner than the upper rubber layer and more excellent in heat resistance than the upper rubber layer. Since the belt is made of a material, in addition to the effect of the invention described in claim 1, there is an effect that the belt easily bends in the reverse direction, cracks are less likely to occur in the compressed rubber layer, and the running life of the belt can be improved.

In the invention of claim 4 of the present application, an upper rubber layer made of a chloroprene rubber composition and a lower rubber layer made of a hydrogenated nitrile rubber composition or a rubber composition of chlorosulfonated polyethylene are used for the compressed rubber layer. The combination has the effect that the belt is more likely to reversely bend and the compression rubber layer is less likely to crack, thereby improving the running life of the belt.

[Brief description of the drawings]

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

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 power transmission V-belt 2 adhesive rubber layer 3 core wire 4 cover canvas 5 extension rubber layer 7 compression rubber layer 9 upper rubber layer 10 lower rubber layer

──────────────────────────────────────────────────続 き Continued on front page (51) Int.Cl. ⁶ Identification code FI F16G 5/00 F16G 5/00 E

Claims (4)

[Claims] 1. An adhesive rubber layer in which a cord made of a cord is embedded, an extension rubber layer above the adhesive rubber layer, and a compression rubber layer below the adhesive rubber layer, and the belt periphery is covered with a cover canvas. In the power transmission V-belt, a twisted yarn having a total denier number of 8,000 to 40,000 in which the above-mentioned core wire is twisted with a group of polyester fiber filaments mainly composed of ethylene-2,6-naphthalate is used. V belt for power transmission. 2. The power transmission V-belt according to claim 1, wherein the stress at 3% elongation of the belt is 3.0 g / denier or more. 3. A compression rubber layer comprising an upper rubber layer and a lower rubber layer, wherein the lower rubber layer is made of a rubber composition thinner than the upper rubber layer and more excellent in heat resistance than the upper rubber layer. The power transmission V-belt as described in the above. 4. The power transmission according to claim 3, wherein an upper rubber layer made of a chloroprene rubber composition and a lower rubber layer made of a hydrogenated nitrile rubber composition or a chlorosulfonated polyethylene rubber composition are used for the compressed rubber layer. V belt.