JP2000320616A - Core wire for transmitting belt and transmitting belt using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a core wire for a transmitting belt whose parallelness is improved in strands for improving bending fatigue performance together with residual strength after running a belt and strength keeping ratio, and a transmitting belt using the same. SOLUTION: This transmitting belt is a V-ribbed belt adopting as a core wire 4 a strand code of totally 3,000 to 9,000 deniers prepared by firstly twisting multifilament group made of one bundle of polyester fiber filaments of 500 to 1,500 deniers composed of units of ethyrene-2,6-naphtharate to obtain first strands, secondly twisting the first strands in an opposite direction after bundling two pieces of the first strands to obtain second strands, and thirdly twisting the three bundles of second strands in the same direction or opposite direction of the second strands.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a core wire for a power transmission belt and a power transmission belt using the same. The present invention relates to a transmission belt core wire with improved flex fatigue and a transmission belt using the same.

[0002]

2. Description of the Related Art A power transmission belt is composed of an extension portion, a cushion rubber layer having a cord embedded in the longitudinal direction of the belt, and a compression portion disposed adjacent to the cushion rubber layer. More recently, instead of a V-belt, a core wire is embedded in a cushion rubber layer, a cover canvas is laminated on the upper portion of the cushion rubber layer as necessary, and a plurality of ribs are provided below the cushion rubber layer. A V-ribbed belt provided with a portion is widely used instead of the V-belt as a power transmission for driving an auxiliary device such as an air conditioner or an alternator of an automobile.

At present, a cord of polyethylene terephthalate (PET) fiber is generally used as the cord. This is because PET fibers have a better balance of strength, elastic modulus, fatigue resistance and the like than other fibers.

[0004]

However, when the heat shrinkage stress of the belt is increased in order to reduce the decrease in the tension during the running of the belt, there has been a problem that the dimensional stability over time deteriorates. To improve the dimensional stability over time, a rubber reinforcing material using polyethylene-2,6-naphthalate (PEN) fiber and having good heat resistance and dimensional stability has been disclosed in
No. 16739. However, there is a problem that the bending fatigue property is poor as compared with the PET fiber.

[0005] Further, in order to improve the bending fatigue, PE
A method in which the filament angle of the N-fiber core wire is set to 15 to 25 degrees (Japanese Patent Application Laid-Open No. 5-313237) and a method in which PEN filaments and PET filaments are twisted (Japanese Patent Application Laid-Open No. 7-127690) have also been proposed. I have. However, also in this case, there was a problem that the modulus, which is one of the characteristics of the cord using the PEN fiber, was lowered.

The present invention has been made to solve such a problem. In order to solve the problem, the alignment of the cord is improved, the bending fatigue property is improved, and the remaining strength or strength after running the belt is improved. An object of the present invention is to provide a transmission belt core wire with an improved retention and a transmission belt using the same.

[0007]

That is, the invention according to claim 1 of the present application is a core wire used for a power transmission belt, which is made of a polyester fiber filament having ethylene-2,6-naphthalate as a main constituent unit. ~ 1,500
A bundle of multifilaments of denier is ply-twisted to form a ply-twisted rope, and two such cords are bundled and medium-twisted in the opposite direction to the p-twisting direction to form a ply-twisted rope. This is a core for power transmission belts, which is a twisted cord with a total denier of 3,000 to 9,000 denier by twisting in the same direction or in the opposite direction to the middle twist. Fatigue is improved, and cord residual strength and strength retention after belt running are increased.

According to a second aspect of the present invention, there is provided a power transmission belt comprising an extension portion, a cushion rubber layer in which a cord is embedded along the belt longitudinal direction, and a compression portion disposed adjacent to the cushion rubber layer. The above core wire is ethylene-2,6
-A multifilament group of a bundle of 500 to 1,500 deniers composed of polyester fiber filaments having naphthalate as a main constituent unit is ply-twisted to form a ply-twisted rope, and two such plied ropes are bundled and opposite to the direction of the p-twist. And twisted in the same direction to form a middle-twisted lanyard, bundling the three stranded ropes and twisting them in the same or opposite direction as the middle-twist to reduce the total denier to 3,000.
The transmission belt is a twisted cord having a denier of ~ 9,000. Since the above-mentioned cord is used, the alignment of the cord is improved, and the bending fatigue is improved. Increase residual strength and retention rate.

According to a third aspect of the present invention, there is provided the power transmission belt, wherein the power transmission belt includes an extension portion, a cushion rubber layer having a cord embedded in the belt longitudinal direction, and a plurality of belts extending in the circumferential direction of the belt adjacent to the cushion rubber layer. V-ribbed belt consisting of a compression section having ribs, which can increase the residual strength of the belt after running and the retention rate of the strength and improve its bending fatigue property,
It can be used for power transmission for driving auxiliary equipment such as air conditioners and alternators for automobiles.

[0010]

Next, a V-ribbed belt according to the present invention will be specifically described with reference to the accompanying drawings. FIG.
The V-ribbed belt 1 shown in FIG. 1 comprises an extension portion 2 made of a cover canvas 3, a cushion rubber layer 5 in which a cord 4 made of a cord is embedded, and a compression portion 6 which is an elastic layer below the cushion rubber layer 5. The compression section 6 has a plurality of trapezoidal ribs 7 extending in the belt longitudinal direction and having a substantially triangular cross section.

The rib 7 is made of hydrogenated nitrile rubber, hydrogenated nitrile rubber to which an unsaturated metal salt of carboxylic acid is added, chloroprene rubber, natural rubber, CSM, ACS
M, SBR, ethylene-alpha-olefin elastomers are used. Hydrogenated nitrile rubber has a hydrogenation rate of 8
In order to exhibit heat resistance and ozone resistance characteristics at 0% or more, 90% or more is preferable. 80% hydrogenation rate
Heat resistance and ozone resistance of hydrogenated nitrile rubbers less than extremely lower. In consideration of oil resistance and cold resistance, the amount of bound acrylonitrile is preferably in the range of 20 to 45%.

A typical ethylene-alpha-olefin elastomer is EPDM,
This refers to a rubber composed of an ethylene-propylene-diene monomer. Examples of diene monomers include dicyclopentadiene, methylene norbornene, ethylidene norbornene, 1,4-hexadiene, cyclooctadiene, and the like. Of course, ethylene-propylene rubber (EPR) can also be used.

The ribs 7 are mixed with short fibers made of nylon 6, nylon 66, polyester, cotton, and aramid to improve the lateral pressure resistance of the ribs 7 and to form the ribs 7 which are to be in contact with the pulleys. The short fibers protrude from the surface to reduce the friction coefficient of the ribs 7 and reduce noise during belt running. Among these short fibers, it is desirable to use aramid fibers which are rigid and strong and have abrasion resistance in combination with other fibers.

In order for the above-mentioned aramid short fibers to sufficiently exhibit the above-mentioned effects, the fiber length of the aramid fibers should be 1-20.
mm, the amount of addition is 1 to 3 with respect to 100 parts by weight of rubber.
0 parts by weight. This aramid fiber has an aromatic ring in the molecular structure, for example, trade names Conex, Nomex,
Kevlar, Technora, Twaron and the like. When the amount of the aramid short fiber is less than 1 part by weight, the rubber of the rib 7 has a disadvantage that the rubber easily sticks and wears. On the other hand, when the amount exceeds 30 parts by weight, the short fiber is uniformly dispersed in the rubber. Will not be dispersed.

Further, in order to improve the adhesion of the ribs 7 to the rubber, the aramid short fibers are bonded with a processing liquid selected from an epoxy compound or an isocyanate compound, an RFL liquid, or both processing liquids. It is processed.

The above-mentioned core wire 4 is made of ethylene-
A multifilament group of a bundle of 500 to 1,500 deniers composed of polyester fiber filaments having 2,6-naphthalate as a main constituent unit is ply-twisted to form a plied twisted rope, and two such cords are bundled and plied. Twisted in the opposite direction to the middle twisted rope, bundling the three cords and twisting them in the same or opposite direction as the middle twist to reduce the total denier to 3,
It is a twisted cord having a denier of 000 to 9,000. The number of twists of this cord is 5 to 18/10 cm, the number of twists is 15 to 50/10 cm, and the number of twists is 3 to 20.
/ 10 cm. If the total denier is less than 3,000, the modulus and strength of the core wire become too low, and if it exceeds 9,000, the thickness of the belt increases, and the flex fatigue becomes 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 bonding process of the core wire 4 includes (1)
The untreated cord is impregnated in a tank containing a treatment liquid selected from an epoxy compound and an isocyanate compound, and is pre-dipped. (2) Drying by passing through a drying furnace set at 160 to 200 ° C. for 30 to 600 seconds. (3) Then, immersed in a tank containing an adhesive liquid composed of an RFL liquid,
(4) It is passed through a stretching heat setting processor set at a temperature of 210 to 260 ° C. for 30 to 600 seconds to stretch it by −1 to 2% to obtain a stretching treatment code.

Examples of the epoxy compound include polyhydric alcohols such as ethylene glycol, glycerin, and pentaerythritol; reaction products of polyalkylene glycols such as polyethylene glycol with halogen-containing epoxy compounds such as epichlorohydrin; (4-hydroxyphenyl) dimethylmethane,
It is a reaction product with polyhydric phenols such as phenol-formaldehyde resin and 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 here is chloroprene, styrene-butadiene-vinylpyridine terpolymer, hydrogenated nitrile, NBR, CSM, etc.

The cord subjected to the stretching heat setting treatment has a spinning pitch, that is, a core winding pitch of 0.8 to 0.8 mm.
By setting the thickness to 1.3 mm, a belt having a high modulus can be finished. If it is less than 0.8 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.

The cover canvas 3 is a fabric woven in a plain weave, a twill weave, a satin weave, or the like using a yarn made of cotton, polyamide, polyethylene terephthalate, and aramid fiber.

When the aramid fiber is used, the modulus of the belt can be increased, but since there is no heat shrinkage, a separate auto tensioner is required, and there is a disadvantage that the transmission mechanism becomes complicated. However, ethylene-2,6
-A core wire using a polyester fiber whose main constituent unit is naphthalate causes heat shrinkage, so that an auto tensioner may not be used.

An example of a method for manufacturing a V-ribbed belt is as follows. First, after winding one or a plurality of cover canvases and an adhesive rubber layer around the peripheral surface of a cylindrical forming drum, a core wire made of a processing cord is spirally spinned on this,
Further, after a compressed rubber layer is sequentially wound to obtain a laminate, the laminate is vulcanized to obtain a vulcanized sleeve. Next, the vulcanization sleeve is hung between the drive roll and the driven roll, and is run under a predetermined tension, and the rotated grinding wheel is moved so as to abut the running vulcanization sleeve to compress the vulcanization sleeve. A plurality of 3 to 100 groove portions are polished at once on the surface of the rubber layer. 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 present invention also includes, in addition to the above-mentioned V-ribbed belt, a V-belt 8 having a cover canvas 3 attached only to the upper and lower surfaces of the belt as shown in FIG. This V
The belt 8 embeds the cord 4 in the cushion rubber layer 5,
On the lower side, there is a compressed portion 6 which is an elastic layer in which short fibers are oriented in the width direction. Cogs may be provided in the compression section 6 at predetermined intervals along the longitudinal direction.

[0027]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to specific examples. Example 1, Comparative Examples 1 to 3 As a cord, one bundle of 1,000 denier ethylene-
Using 2,6-naphthalate fiber (PEN fiber) and polyethylene terephthalate fiber (PET fiber) having a bundle of 1,100 denier, cords having the configuration and the number of twists shown in Table 1 were prepared. Was pre-dipped into 90 g of toluene with an adhesive consisting of 10 g of PAPI (a polyisocyanate compound manufactured by Kasei Upjohn Co., Ltd.), and then placed in a drying oven set at a temperature of about 170 to 190 ° C. for 10 to 30.
After drying for 0 second, the RFL solution (chloroprene latex 100 parts by weight, resorcinol 14.6 parts by weight, formalin 9.2 parts by weight, caustic soda 1.5 parts by weight, water 2)
62.5 parts by weight), and subjected to a heat stretching and fixing treatment under the treatment conditions shown in Table 1 to obtain a treated cord.

[0028]

[Table 1]

Next, a V-ribbed belt (3PK1100) was manufactured using the above cord. The method for manufacturing this belt is as follows. First, after a single ply of a woven cloth with rubber obtained by friction of chloroprene rubber was wound around a plain woven fabric made of cotton yarn in which a warp and a weft are wound around a cylindrical mold, an adhesive rubber sheet made of a chloroprene rubber composition shown in Table 2 was wound thereon. The above cord was spun thereon, and a rubber layer composed of the chloroprene rubber composition shown in Table 2 was wound thereon to complete the molding. 160 ° by a known method
C, vulcanized for 30 minutes to obtain a cylindrical vulcanized rubber sleeve.

The above-described 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.

In the produced V-ribbed belt, the cords made of the above-mentioned stretch-fixed cords are embedded in the cushion rubber layer, and a cotton sail cloth with rubber is laminated one ply on the upper side, and on the other side under the cushion rubber layer. There was a compression section and three ribs were in the longitudinal direction of the belt. This V-ribbed belt is a K-type 3-ribbed belt having a length of 1,100 mm according to the RMA standard, a rib pitch of 3.56 mm, and a rib height of 2.0.
mm, a rib angle of 40 °, and a belt thickness of 4.3 mm.

Here, the compression part and the cushion rubber layer are
Each was prepared from the rubber composition shown in Table 2, kneaded with a Banbury mixer, and then rolled with a calendar. The compression section contains short fibers and is oriented in the belt width direction. The short fibers were previously subjected to an adhesive treatment with the RFL solution.

[0033]

[Table 2]

Next, the static and dynamic performance of the V-ribbed belt was evaluated. The results are shown in Table 1.

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

Cord unalignment difference Untreated cord having a length of 300 mm is untwisted to the state of the lower twisted rope, and the difference between the longest and shortest lengths of the lower twisted rope is divided by the original length (300 mm). I asked.

(2) Belt Intermediate Elongation The belt was pulled at a speed of 50 mm / min, and
The elongation percentage when a stress of 245 N was applied per rib was measured.

(3) Belt Cutting Elongation The belt was pulled at a speed of 50 mm / min, and the elongation when the belt was cut was measured.

(3) Belt Strength The belt was pulled at a speed of 50 mm / min, and the maximum load when the belt (cord) was cut was divided by the number of ribs.

(4) Belt Residual Strength A belt is hung on a traveling tester equipped with a driving pulley having a diameter of 120 mm, a driven pulley having a diameter of 120 mm, and a driven pulley having a diameter of 45 mm, and a load of 102 kgf is applied to the driven pulley having a diameter of 120 mm. After applying tension to the belt by hanging the belt, the driving pulley was rotated at 4800 rpm in an atmosphere at room temperature to run the belt for 1,000 hours, and then the belt strength was measured by the above method (3).

(5) Belt strength retention The belt strength was determined by dividing the belt residual strength by the belt strength.

(6) Occurrence rate of whiskers on the side of the belt 100 belts were inspected, and the ratio of the number of belts in which the lower strand of the core wire protruded from the side surface of the belt in a whisker-like shape with a length of 3 mm or more was calculated.

As described above, in the embodiment, the first twist, the middle twist,
It can be seen that since the twisting is provided, the difference in cord alignment is particularly small, the belt strength and the belt remaining strength are improved, and the whiskers on the side surface of the belt are small.

[0044]

As described above, according to the invention of claim 1 of the present application, a polyester fiber filament composed mainly of ethylene-2,6-naphthalate is used.
A bundle of multifilaments having a denier of 0 to 1,500 denier is ply-twisted to form a lower-twisted rope, and two such bundles are bundled and twisted in a direction opposite to the direction of the lower-twist to form a medium-twisted rope. Three ropes
A core cord for a power transmission belt, which is a twisted cord having a total denier of 3,000 to 9,000 denier by being twisted in the same direction or in the opposite direction as the middle twist of the main bundle, and the uniformity of the cord is improved. As a result, the bending fatigue property is improved, the cord residual strength and the strength retention rate after the belt running can be improved, and there is an effect that the generation rate of whiskers on the side of the belt can be reduced.

According to the second aspect of the present invention, there is provided a power transmission belt using the core wire according to the first aspect. This has the effect of improving the resilience, improving the cord residual strength and the strength retention rate after running the belt, and reducing the occurrence of whiskers on the side of the belt.

According to a third aspect of the present invention, there is provided a V-ribbed belt using the cord according to the first aspect, wherein the belt residual strength after running and the strength retention rate are increased to greatly improve the bending fatigue property. It can be used for power transmission of auxiliary equipment such as an air conditioner and an alternator of an automobile.

[Brief description of the drawings]

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

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 V-ribbed belt 2 Extension part 3 Cover canvas 4 Core wire 5 Cushion rubber layer 6 Compression part 7 Rib

Continuation of the front page F term (reference) 3B153 AA08 AA47 AA50 BB01 BB20 CC21 CC27 CC29 FF12 FF15 GG01 GG05 GG40

Claims (3)

[Claims] 1. A core used for a power transmission belt, comprising a polyester fiber filament having ethylene-2,6-naphthalate as a main constituent unit, comprising 500 to 1.5.
A bundle of multifilaments of 00 denier is ply-twisted to form a ply-twisted rope, and two such cords are bundled and medium-twisted in a direction opposite to the p-twisting direction to form a ply-twisted rope. A core cord for a power transmission belt, wherein the core cord is a twisted cord having a total denier of 3,000 to 9,000 denier by being twisted in the same direction or in the opposite direction as the bundled middle twist. 2. A power transmission belt comprising: an extension portion; a cushion rubber layer in which a cord is buried along a belt longitudinal direction; and a compression portion disposed adjacent to the cushion rubber layer.
The above-mentioned core wire is composed of a polyester fiber filament having ethylene-2,6-naphthalate as a main constituent unit;
A bundle of multifilaments of 500 to 1,500 denier is ply-twisted to form a lower-twisted rope, and two such bundles are bundled and twisted in a direction opposite to the direction of the lower-twist to form a middle-twisted rope. Bundling three ropes and twisting them in the same direction or the opposite direction as the middle twist
A transmission belt comprising a twisted cord having a talden number of 3,000 to 9,000 denier. 3. A power transmission belt comprising: an extension portion; a cushion rubber layer having a core embedded in a longitudinal direction of the belt; and a compression portion having a plurality of ribs extending in a circumferential direction of the belt adjacent to the cushion rubber layer. The power transmission belt according to claim 2, wherein the power transmission belt is a V-ribbed belt made of: