JP2002227934A - Power transmission belt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power transmission belt which shows an excellent power transmission performance during normal and water injection times, and high resistances to noise generation under low tension. SOLUTION: In a V-ribbed belt 1, a core wire 3 is buried in a bonded rubber layer 2 along the longitudinal direction of a belt. The V-ribbed belt contains a compressed rubber layer 4 in which a plurality of ribs are provided on the bottom of the bonded rubber layer 2 in the longitudinal direction of a belt, and a structure in which, as a stretch layer, foundation clothes 5 are laminated on the top of the bonded rubber layer 2. In the compressed rubber layer 4, a short fiber component of 5-40 pts.mass is incorporated based on 100 pts.mass of the contained rubber components, where the short fiber is a mixed short fiber formed by mixing at least two types of short fibers including a short fiber of 0.1-5 μm and a rigid short fiber at the compounding ration of 1/5-5/1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power transmission belt, and more particularly to a power transmission belt in which short fibers are mixed in at least a compression rubber layer.

[0002]

2. Description of the Related Art In recent years, with the advancement of functions and performance of automobile parts, especially in the rubber industry, there has been a demand for rubber products that can withstand severe use environments. The properties of rubber products are determined by the selection of raw rubber and the combination of compounding agents and the like. In recent years, short fibers have generally been compounded for the purpose of improving reinforcing properties, abrasion resistance, sound resistance, and the like.

[0003] Among rubber products used for automobile parts, there is a power transmission belt, which is widely used, for example, for power transmission of auxiliary machines such as an air compressor and an alternator of an automobile. In this type of belt, cotton on the ribs,
By burying short fiber groups such as nylon, vinylon, rayon, and aramid fibers while maintaining the orientation to the belt width, the lateral force resistance of the friction transmission part of the belt is increased, and a part of the buried short fibers is actively used. There has been proposed a power transmission belt that aims at a frictional performance of a rib portion and an effect of suppressing sound generation due to adhesion by being exposed to both side walls of the friction transmission portion. In addition, as a short fiber projecting on both side walls of the friction transmission portion to further improve the effect of the belt,
In particular, Japanese Patent Application Laid-Open No. 1-164839 discloses a power transmission belt intended to improve the durability of the belt itself by using aramid fiber and thereby abrasion resistance peculiar to aramid fiber.

However, when the above-mentioned belt is used as a power transmission belt for driving an auxiliary machine such as an air compressor of an automobile (hereinafter referred to as A / C), this A
At the moment when the switch / C is turned on, a sound is generated due to a slip. Normally, when the room temperature in an automobile is high, the A / C is switched off, the belt and the A / C are not linked, and only the belt is idle at high speed.
Therefore, at the moment when the A / C switch is turned on due to a rise in the room temperature in the automobile, the belt and the A / C start interlocking. At this time, a sudden load is applied to the belt. I slipped for a moment and found it to sound.

In general, if the belt tension is high, even if the load is suddenly applied in this manner, the belt does not slip and the problem of sound generation is small. However, as described above, the V-ribbed belt for A / C is used. Even when not, only the belt is spinning at high speed. For this reason, the belt tension gradually decreases due to belt wear, elongation of the core wire, and the like.
The slip which occurs at the moment when the switch C is turned on is also likely to occur, and the problem of sound generation due to the slip also becomes remarkable.

Further, regarding the slip of the power transmission belt and the pulley, there is another cause caused by water. More specifically, when water adheres to the power transmission belt, the friction coefficient between the belt and the pulley decreases, which causes an increase in the slip ratio. In recent years, energy saving,
At the present time, the conditions for durability use have become more stringent against the background of social demands for compactness, and the demands recently demanded have been insufficient with conventional belts containing short fibers.

[0007]

SUMMARY OF THE INVENTION In view of the above problems, an object of the present inventors is to make it difficult to produce sound even at low tension.
An object of the present invention is to provide a power transmission belt having excellent transmission performance. More specifically, by mixing and dispersing and blending two types of short fibers having a specific fiber diameter and fiber type in the compressed rubber layer of the power transmission belt, the transmission performance is excellent even during normal and water injection. In addition, the present invention provides a power transmission belt having an excellent belt sounding prevention effect that suppresses sound generation due to slip even when a sudden load is applied in a state where the belt tension is reduced.

[0008]

The invention according to claim 1 of the present invention is directed to a power transmission belt in which short fibers are dispersed and compounded in at least a compression rubber layer among rubber members constituting the power transmission belt. And a short fiber having a fiber diameter of 0.1.
A power transmission belt using a mixture of at least two types of short fibers of 1 to 5 μm short fibers and 10 to 40 μm rigid short fibers.

According to a second aspect of the present invention, in the power transmission belt according to the first aspect, the compounding ratio of the short fiber of 0.1 to 5 μm and the rigid short fiber of 10 to 40 μm is 1/5 to 5
/ 1.

According to a third aspect of the present invention, there is provided a power transmission belt according to the first or second aspect, wherein the power transmission belt has a thickness of 0.1 to 5 μm.
Is a fibrillated fiber.

According to a fourth aspect of the present invention, in the power transmission belt according to any one of the first to third aspects, the rigid short fibers are aramid short fibers.

According to a fifth aspect of the present invention, in the power transmission belt according to any one of the first to fourth aspects, the short fiber component is blended in an amount of 5 to 40 parts by mass with respect to 100 parts by mass of the rubber component. It is characterized by the following.

According to a sixth aspect of the present invention, in the power transmission belt according to any one of the first to fifth aspects, an adhesive rubber layer having a core buried along the belt length direction; V-ribbed belt comprising a compressed rubber layer having a plurality of rib portions extending to the V-ribbed belt, characterized in that at least the compressed rubber layer uses a rubber composition containing the short fibers.

According to a seventh aspect of the present invention, there is provided a power transmission belt according to any one of the first to sixth aspects, wherein the power transmission belt is an adhesive rubber having a core buried along a belt length direction. And a compressed rubber layer, wherein at least the compressed rubber layer is made of a rubber composition containing the short fibers.

[0015]

FIG. 1 shows a V-ribbed belt 1 as an example of a power transmission belt according to the present invention. The V-ribbed belt 1 has a compression rubber layer 4 in which a core wire 3 is embedded in the adhesive rubber layer 2 along the belt longitudinal direction, and a plurality of ribs provided in the belt longitudinal direction below the adhesive rubber layer 2. I have. Further, on the upper part of the adhesive rubber layer 2, there is a structure in which a base cloth 5 is laminated as an extension layer. Short fibers are dispersed and compounded in the compressed rubber layer 4, and most of the short fibers are in a range of 70 ° to 110 ° when 90 ° is oriented in a direction perpendicular to the longitudinal direction of the belt. It is oriented in.

As the short fiber used in the present invention, a mixed fiber obtained by mixing at least two kinds of short fibers of a short fiber having a fiber diameter of 0.1 to 5 μm and a rigid short fiber having a fiber diameter of 10 to 40 μm is used. By blending short fibers having a fiber diameter of 0.1 to 5 μm, relatively thin short fibers form fine irregularities on the surface of the compressed rubber layer, and add high transmission performance to the belt during normal running. The fiber diameter is 10 to 40 μm
The relatively thick rigid short fibers cover the rubber surface and show high transmission performance in running during water injection. And 0.1 to 5 μm short fiber and 10 to 10 μm
By mixing the rigid fibers of 40 μm, it is possible to provide a power transmission belt excellent in the effect of suppressing the sound generation due to slip even if the belt tension is low. A single blend of each of these cannot provide a belt that is difficult to sound even at low tension.
It is not clear why the combination of these two types has a sound-suppressing effect at low tension, but the present inventors have found the above effects by conducting intensive studies on fiber diameter and fiber type. .

The types of short fibers having a fiber diameter of 0.1 to 5 μm include cotton, polyester, polyethylene, nylon,
Vinylon, rayon, wholly aromatic polyester, polyparaphenylene benzobisoxazole, aramid fiber and the like. The above fibers may or may not be fibrillated, but if fibrillated short fibers are blended, finer irregularities occur on the rubber surface, and the above-mentioned effect is enhanced.

Examples of the rigid short fibers having a fiber diameter of 10 to 40 μm include wholly aromatic polyesters, aramid fibers, and polyparaphenylenebenzobisoxazole short fibers. Among them, aramid fibers are widely used and preferably used.

The mixing ratio of the short fiber having a fiber diameter of 0.1 to 5 μm and the rigid short fiber having a fiber diameter of 10 to 40 μm is 1/5.
〜5 / 1 is preferred. If it is less than 1/5, the transmission performance during normal running deteriorates, and if it exceeds 5/1, the transmission performance during water injection decreases. As a suitable compounding condition of the mixed short fibers in the compressed rubber layer 4 of the V-ribbed belt 1 which is the power transmission belt according to the present invention, it is preferable to mix 5 to 40 parts by mass with respect to 100 parts by mass of the rubber. When the amount of the mixed short fiber is less than 5 parts by mass, the rubber of the compressed rubber layer 4 has a disadvantage that the rubber easily sticks and wears. On the other hand, when the amount exceeds 40 parts by mass, the short fiber is uniformly dispersed in the rubber. They are not dispersed and cracks are likely to occur. In addition to the above-mentioned mixed short fibers, short fibers made of other materials can be added.

The short fibers used are preferably subjected to an adhesive treatment by the following method. The above fiber is treated in a filament state with an RFL solution in which a resorcinol-formalin precondensate and a rubber latex are mixed. In this case, it is preferable that the molar ratio of resorcinol to formalin be 3/1 to 1/3 in order to enhance the adhesive strength. In addition, the RFL liquid has a solid content ratio of resorcinol-formalin initial condensate and rubber latex of 1/1 to 1/5, and the solid content of the RFL solution is 3 to 10% by mass. It is preferable in increasing the effect of the adhesive force. If it exceeds 1/1,
When the cohesive force of the short fibers increases, the dispersibility deteriorates. Conversely, when the short fibers are less than 1/5, the adhesive force between the rubber and the short fibers decreases, and the tensile strength also decreases. Further, when the solid content of the RFL liquid exceeds 10% by mass, the treatment liquid hardens and the filaments of the short fibers are hardly divided, and conversely, when the amount is less than 3% by mass, the dispersibility and the tensile strength are reduced. No improvement effect can be expected. Examples of the rubber latex include styrene-butadiene-vinylpyridine terpolymer, chlorosulfonated polyethylene, hydrogenated nitrile rubber, epichlorohydrin, natural rubber, SBR, chloroprene rubber, olefin-vinyl ester copolymer, EPDM and the like. Latex is mentioned. In addition, the temperature of the treatment liquid at the time of performing the adhesion treatment is adjusted to 5 to 40 ° C, and the immersion time is 0.5 to 30 ° C
Seconds and 1 in an oven adjusted to 200-250 ° C.
Heat treatment for ~ 3 minutes.

Further, in addition to the above-mentioned processing, it is also possible to perform an overcoat processing. The rubber compound is immersed in a rubber paste dissolved in a solvent which is a good solvent for the rubber compound and is selected from aromatic hydrocarbons such as toluene and xylene, and aliphatic ketones such as methyl ethyl ketone, and overcoated. Immersion time is 0.5-30 seconds, 80-200 °
C is passed through an oven adjusted to 1 to 3 minutes for heat treatment.

The fibers subjected to the adhesive treatment as described above can be cut into a desired length to obtain short fibers. The short fiber used in the present invention has an appropriate fiber length of 1 to 20 mm.
In the present invention, after the untreated filament yarn is treated with a pretreatment liquid containing at least one kind of, for example, a nitrile rubber-modified epoxy resin or an epoxy resin and an isocyanate compound, the short fibers treated with the RFL liquid are added to the rubber composition. You can also.

The base fabric 5 is a canvas selected from a woven fabric, a knitted fabric, and a non-woven fabric. Known fiber materials can be used as constituent fiber materials.For example, natural fibers such as cotton and hemp,
Examples include inorganic chemical fibers such as metal fibers and glass fibers, and organic chemical fibers such as polyamide, polyester, polyethylene, polyurethane, polystyrene, polyfluoroethylene, polyacryl, polyvinyl alcohol, wholly aromatic polyester, and aramid.

The base cloth 5 is immersed in a resorcinol-formalin-latex liquid (RFL liquid) according to a known technique.
The unvulcanized rubber is rubbed against the base cloth 5, or immersed in an RFL solution and then immersed in a soaking solution in which the rubber is dissolved in a solvent. The RFL solution may be appropriately mixed with a carbon black solution to blacken the treated material, or a known surfactant may be added in an amount of 0.1 to 5.0% by mass.

The main rubber of the compressed rubber layer 4 includes natural rubber, polyisoprene rubber, polybutadiene rubber, styrene-butadiene copolymer rubber, chloroprene rubber, ethylene-α-olefin copolymer such as ethylene-propylene rubber. Polymer rubber, nitrile rubber (NBR), hydrogenated nitrile rubber (H-NBR) to which unsaturated carboxylic acid metal salt is added, alkylated chlorosulfonated polyethylene (ACSM), chlorosulfonated polyethylene rubber (CSM), etc. As a main component, and a reinforcing agent such as carbon black, a filler, a softening agent, an antioxidant, a vulcanization aid, a vulcanizing agent such as sulfur or an organic peroxide, and the like are added and mixed.

On the other hand, the same rubber as the compressed rubber layer 4 can be used for the adhesive rubber layer 2. It is preferable not to mix short fibers as a blend, but if necessary, carbon black, an enhancer such as silica, a filler such as calcium carbonate and talc, a plasticizer, a stabilizer, a processing aid, and a coloring agent. Those used for ordinary rubber compounding are used.

As a method for producing the rubber composition containing short fibers, first, as a masterbatch kneading in the first step, 5 to 40 parts by mass of rubber is mixed with 100 parts by mass of rubber in a closed kneader such as a Banbury mixer. Mixed short fiber and 1-10
After mixing and kneading the mass part of the softening agent, the kneaded master batch is once released and cooled to 20 to 50 ° C. This is to prevent rubber scorch. Next, a predetermined amount of a reinforcing agent, a filler, an antioxidant, a vulcanization accelerator, a vulcanizing agent, and the like are kneaded with the obtained master batch using a Banbury mixer and an open roll. Depending on the type of rubber, the kneaded master batch is once released and does not need to be cooled, and it is also possible to perform finish kneading continuously. The kneading method is not limited to the above method, and the kneading means is not limited to, for example, a Banbury mixer, a roll, a kneader, and an extruder. it can. The vulcanization method is also not limited, and vulcanization is performed by a known method using a vulcanizing apparatus such as a mold heating, a hot air heating, a rotary drum vulcanizer, and an injection molding machine.

As the core wire 3, polyester fiber, aramid fiber and glass fiber are used.
Adhesive-treated cords having a total denier of 4,000 to 8,000 in which polyester fiber filaments having 2,6-naphthalate as a main constituent unit are twisted can reduce the belt slip rate and extend the belt life. Preferred. The twist number of this cord is 10-23 / 10
cm, and the number of twists is 17 to 38/10 cm. If the total denier is less than 4,000, the modulus and strength of the cord become too low, and if it exceeds 8,000, the belt becomes thick and the bending fatigue becomes poor.

Ethylene-2,6-naphthalate is usually synthesized by subjecting naphthalene-2,6-dicarboxylic acid or an ester-forming derivative thereof to condensation polymerization with ethylene glycol under appropriate conditions in the presence of a catalyst. . 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.

The core 3 is subjected to an adhesive treatment for the purpose of improving the adhesiveness with rubber. As such an adhesive treatment, the fiber is made of resorcin-formalin-latex (RF
L) Generally, after immersion in the liquid, the adhesive layer is uniformly formed on the surface by heating and drying. However, without being limited to this, there is a method of performing a pretreatment with an epoxy or isocyanate compound and then treating with an RFL solution.

The cord subjected to the adhesive treatment can be finished into a belt having a high modulus by setting the spinning pitch, that is, the winding pitch of the core wire to 1.0 to 1.3 mm. If it is less than 1.0 mm, the cord runs over the adjacent cord and cannot be wound, while if it exceeds 1.3 mm, the modulus of the belt gradually decreases.

Next, an example of a method for manufacturing the V-ribbed belt 1 will be described below. First, after wrapping the base cloth and the adhesive rubber around the peripheral surface of the cylindrical forming drum, a core wire made of a rope is spirally spun on this, and a compressed rubber is sequentially wrapped to obtain a laminated body. This is vulcanized to obtain a vulcanized sleeve. Next, the vulcanization sleeve is hung on a drive roll and a driven roll, and is run under a predetermined tension, and further, the rotated grinding wheel is moved so as to abut the running vulcanization sleeve to thereby form the vulcanization sleeve. A plurality of 3 to 100 groove portions are ground on the surface of the compressed rubber layer at a time. The vulcanized sleeve obtained in this manner is removed from the drive roll and the driven roll, and the vulcanized sleeve is hung on another drive roll and the driven roll to travel, cut to a predetermined width by a cutter, and cut into individual pieces. Finish with a V-ribbed belt.

The V-ribbed belt 1 is an embodiment of the present invention and is not limited to this. For example, as another example of the power transmission belt according to the present invention, V
The belt 6 is shown in FIG. The V-belt 6 has a cord 11 embedded in the adhesive rubber layer 9 along the longitudinal direction of the belt, and has an extended rubber layer 7 and a compressed rubber layer 10 adjacent to the upper and lower portions of the adhesive rubber layer 9. The layer 7 has a structure in which a base fabric 8 is laminated on the surface. In addition, if necessary, the compressed rubber layer 10
May be provided with cogs at predetermined intervals in the belt longitudinal direction.
For the compressed rubber layer 10, a rubber composition containing 5 to 40 parts by mass of the mixed short fiber according to the present invention is used. still,
For each rubber layer, the same rubber as the above-described V-ribbed belt 1 can be used.

[0034]

The present invention will be described in more detail with reference to the following examples. Examples 1 to 3 and Comparative Examples 1 to 4 The compounding ingredients were kneaded with a Banbury mixer in the composition shown in Table 1 and rolled with a roll to obtain a rubber sheet having a thickness of 1 mm. For the short fibers, each of the fibers shown in Table 3 was immersed in the RFL solution, and then heat-treated at 200 ° C. for 1 minute to use the cut short fibers. The composition of the RFL solution is shown in Table 2.

[0035]

[Table 1]

[0036]

[Table 2]

[0037]

[Table 3]

As a manufacturing process of the V-ribbed belt, first,
After wrapping a single ply of a canvas with rubber obtained by friction of chloroprene rubber on a plain woven fabric in which a warp and a weft are made of cotton yarn, a cylindrical mold is wound with an adhesive rubber sheet made of a chloroprene rubber composition shown in Table 1, and further thereon. A cord made of polyester fiber was spun, and a compressed rubber layer made of a chloroprene rubber composition also shown in Table 1 was wound to complete molding. The chloroprene rubber composition used for the adhesive rubber layer is a composition excluding short fibers.
This was vulcanized at 160 ° C. for 30 minutes by a known method to obtain a cylindrical vulcanized rubber sleeve.

The above vulcanized rubber sleeve was mounted on a driving roll and a driven roll of a polishing machine, and was rotated after applying tension. A polishing wheel having a 150-mesh diamond mounted on its surface was rotated at 1600 rpm, and this was brought into contact with a vulcanization sleeve to polish a rib portion. After the sleeve taken out of the polishing machine was set on the cutting machine, it was cut while rotating.

The produced V-ribbed belt has a core wire embedded in a cushion rubber layer, and a cotton canvas with rubber on one side thereof.
On the other hand, a compression portion was provided below the cushion rubber layer, and three ribs were provided in the belt longitudinal direction. This V-ribbed belt is 1,100m long according to RMA standard.
m K-type 3-ribbed belt with a rib pitch of 3.56m
m, rib height 2.9 mm, rib angle 40 °, and various belt thicknesses. The short fibers blended in the compressed rubber layer are oriented in the belt width direction.

The V-ribbed belt thus obtained was subjected to a running test in the layout shown in FIG. 3, and the load was increased while the axial load was constant, and the load when the slip was 2% was measured.
This value is an index indicating the transmissibility, and the higher the load, the less the slippage, and the higher the transmission performance. The results are shown in Table 3. Also, 0.92 kgf in the layout of FIG.
A running test was performed by applying a constant load of m and 1.53 kgf · m. The shaft load was gradually reduced, and the belt tension when sound was generated was measured. This value is an index indicating the pronunciation, and the lower the value, the more difficult it is to pronounce. The results are shown in Table 3.

From Table 3, it can be seen that in Examples 1 to 3 in which vinylon short fibers having a fiber diameter of 1 μm and aramid short fibers having a fiber diameter of 14 μm were blended, the transmission performance during normal operation and during water injection was excellent, and the sound generation limit tension was increased. It is also difficult to pronounce even at low tension. In Comparative Example 3 in which only vinylon short fibers having a fiber diameter of 1 μm were blended, the transmissivity during normal operation was high, but the transmissivity during water injection was inferior. On the other hand, in Comparative Example 4 in which only aramid short fibers having a fiber diameter of 14 μm were blended, the transmissibility during water injection was excellent, but the transmissivity during normal use was low. Further, Comparative Example 1 in which vinylon short fibers having a fiber diameter of 25 μm and aramid short fibers having a fiber diameter of 14 μm and Comparative Example 2 in which vinylon short fibers having a fiber diameter of 25 μm and vinylon short fibers having a fiber diameter of 1 μm were blended, Both the transmission performance at the time of water injection and the sound generation at the time of low tension were inferior to the examples.

[0043]

As described above, in the power transmission belt according to the invention of the present application, among the rubber members constituting the power transmission belt, the short fibers are dispersed in at least the compressed rubber layer and blended. The fiber diameter is 0.1-5μ
m and 10 to 40 μm rigid short fibers are mixed with at least two types of short fibers to provide a power transmission belt having excellent transmission capacity and a high sound-suppression effect at low belt tension. We were able to.

[Brief description of the drawings]

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

FIG. 2 is a sectional perspective view of a V-belt which is a power transmission belt according to the present invention.

FIG. 3 is a diagram showing a layout of a running test related to a transmission performance test and a sound generation performance test of an example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 V-ribbed belt 2 Adhesive rubber layer 3 Core wire 4 Compressed rubber layer 5 Base cloth 6 V belt 7 Extension rubber layer 8 Base cloth 9 Adhesive rubber layer 10 Compressed rubber layer 11 Core wire

Claims (7)

[Claims] 1. A power transmission belt in which short fibers are dispersed and blended in at least a compressed rubber layer among rubber members constituting the power transmission belt, wherein the short fibers having a fiber diameter of 0.1 to 5 μm are used as the short fibers. A power transmission belt, comprising a mixture of at least two kinds of rigid short fibers of 10 to 40 μm. 2. Short fibers of 0.1 to 5 μm and 10 to 40 μm
The power transmission belt according to claim 1, wherein the compounding ratio of the rigid short fibers of m is 1/5 to 5/1. 3. The power transmission belt according to claim 1, wherein the 0.1 to 5 μm short fibers are fibrillated fibers. 4. The power transmission belt according to claim 1, wherein the rigid short fibers are aramid short fibers. 5. The power transmission belt according to claim 1, wherein the short fiber component is blended in an amount of 5 to 40 parts by mass with respect to 100 parts by mass of the rubber component. 6. The power transmission belt is a V belt composed of an adhesive rubber layer having a core embedded in the belt length direction and a compression rubber layer having a plurality of ribs extending in the belt length direction.
The power transmission belt according to any one of claims 1 to 5, wherein the belt is a ribbed belt, and uses a rubber composition containing the short fibers in at least the compressed rubber layer. 7. The power transmission belt comprises an adhesive rubber layer having a core buried along the belt length direction and a compressed rubber layer, and at least the compressed rubber layer contains a rubber containing the short fiber. The power transmission belt according to any one of claims 1 to 6, wherein the power transmission belt comprises a composition.