JP2002227051A - Core wire for transmission belt and v-ribbed belt using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a core wire for transmission belt improving residual strength and retention of strength of a cord or a belt after belt running and improved in bending fatigue resistance thereof and a V-ribbed belt using the core wire. SOLUTION: This core wire 4 is used for the transmission belt and composed of a polyester fiber filament comprising ethylene-2,6-naphthalate as a main constituent. The core wire 4 is an organized cord obtained by performing first twist on the multifilaments having 750-12,000 denier per one bundle to make a small cord 10, bundling 5-8 number of the small cords 10 and performing final twist thereon in the reverse direction of the direction in the first twist to make a molded cord having a total denier of 6,000.

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 V-ribbed belt using the same. More specifically, the present invention has improved the bending strength of the cord or the belt after running by increasing the residual strength and the strength retention of the cord or the belt. The present invention relates to a transmission belt core wire and a V-ribbed belt using the same.

[0002]

2. Description of the Related Art A power transmission belt includes an extension portion, a cushion rubber layer having a cord embedded in a 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 a vehicle.

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, and in order to solve the problem, a transmission belt in which the residual strength and the strength retention of a cord or a belt after running of a belt are increased to improve the bending fatigue thereof. An object of the present invention is to provide a service cord and a V-ribbed belt using the same.

[0007]

That is, the invention according to claim 1 of the present application is a cord used for a power transmission belt, comprising a polyester fiber filament comprising ethylene-2,6-naphthalate as a main constituent unit. 750 to 1,
A multi-filament cord of 2,000 denier multifilament is twisted into a cord, and 5 to 8 such cords are bundled, and the twisted cord is twisted in the opposite direction to the twisting direction to give a total denier of 6,000 denier. In a certain transmission belt cord, the flexibility of the belt is improved because the above cord is used,
The belt residual strength and the strength retention after running can be increased, the bending fatigue property can be improved, and the service life can be improved.

The invention according to claim 2 of the present application has an extension portion, a cushion rubber layer in which a cord is buried along the longitudinal direction of the belt, and a plurality of ribs extending in the circumferential direction of the belt adjacent to the cushion rubber layer. In a V-ribbed belt comprising a compression section, the above-mentioned core wire is formed by twisting a multifilament group having a density of 500 to 1,500 deniers, the bundle comprising polyester fiber filaments comprising ethylene-2,6-naphthalate as a main constituent unit. As a noose, the noose is 5-8
It is a twisted cord with a total denier of 3,000 to 10,000 denier by twisting in the direction opposite to the direction of bottom twisting, with a belt strength of 1.20 to 1.30 kN / rib and belt remaining strength. Is 0.8 to 0.95 kN / rib and the belt strength retention is 65 to 80% in the V-ribbed belt. The use of the above-mentioned cords improves the flexibility of the belt. The belt residual strength and the strength retention rate can be increased to improve the bending fatigue property, and the life of the belt can be improved. Furthermore, the belt residual strength and the strength retention after running can be increased to improve the bending fatigue property, and the belt can be used for power transmission for driving auxiliary equipment such as an air conditioner and an alternator of an automobile.

[0009]

Next, a V-ribbed belt according to the present invention will be specifically described with reference to the accompanying drawings. Figure 1
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 example of an 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 improve 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.

[0015] The core wire 4 may be ethylene-
One bundle consisting of polyester fiber filaments mainly composed of 2,6-naphthalate is 750 to 1.2.
A multi-filament cord having a denier of 6,000 denier is obtained by bundling 5 to 8 strands of a multifilament group having a denier of 6,000 denier. is there. The twist number of this cord is 7-18
/ 10 cm, and the number of lower twists is 20 to 40/10 c
m. FIG. 2 shows a core wire 4 having a 1 × 6 cord configuration, and a bundle of small ropes 1 twisted rightward in the center at the center.
0 is placed, and five similar cords 10 are arranged around the same, and then twisted in the opposite direction. When the total denier is 6,000 denier, the remaining belt strength, the cord strength, and the belt strength retention are excellent.

Further, when the total denier of the code is 6,
When the composition is the same as 000 denier and the composition is 1 × N, when N is less than 5, the cord strength is at a high level, but the residual strength and the strength retention rate of the cord after belt running tend to decrease. When N exceeds 8, the cord strength tends to decrease, and the residual strength of the cord after running the belt tends to decrease.

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.

The bonding process of the core wire 4 is as follows: (1) After impregnating the untreated cord into a tank containing a treatment liquid selected from an epoxy compound and an isocyanate compound, and pre-dip, (3) drying by passing through a drying oven set at a temperature of 200 ° C. for 30 to 600 seconds;
Subsequently, it is immersed in a tank containing an adhesive liquid composed of an RFL solution, and (4) stretched for 1-2% by passing it through a stretching heat setting processor set at a temperature of 210 to 260 ° C. for 30 to 600 seconds. 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 herein includes chloroprene, styrene / butadiene / vinylpyridine terpolymer, hydrogenated nitrile, NBR, etc. It is.

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 will not be able to be wound around the adjacent cord,
On the other hand, 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.

The V-ribbed belt using the cord 4 has a belt strength of 1.20 to 1.30 kN / rib, a belt remaining strength of 0.8 to 0.95 kN / rib, and a belt strength retention of 65. When it is ８０80%, the belt residual strength after running and the strength retention rate can be increased, and the bending fatigue property can be improved.

When the aramid fiber is used, the modulus of the belt can be increased. However, since there is no heat shrinkage, a separate auto tensioner is required, and there is a disadvantage that the transmission mechanism is 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, one or a plurality of cover canvases and an adhesive rubber layer are wrapped around the peripheral surface of a cylindrical forming drum, and a cord made of a rope is spun spirally thereon, and further a compressed rubber layer is sequentially wrapped. After obtaining 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.

[0027]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to specific examples. Examples 1 to 3, Comparative Examples 1 to 4 As bundles, each bundle is 600 denier, 750 denier, 1,000 denier, 1,200 denier, 1,5.
A cord having the configuration and the number of twists shown in Table 1 was prepared using 00 denier ethylene-2,6-naphthalate fiber (PEN fiber) and 1 bundle of 1,100 denier polyethylene terephthalate fiber (PET fiber). After pre-dipping each untreated cord into 90 g of toluene with an adhesive composed of 10 g of PAPI (a polyisocyanate compound manufactured by Kasei Upjohn Co., Ltd.), the cord was passed through a drying oven set at a temperature of about 170 to 190 ° C. for 10 to 300 seconds. Drying and subsequently impregnating with an adhesive consisting of RFL liquid (100 parts by weight of chloroprene 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) Under the processing conditions shown in Table 1, a hot stretch fixing treatment was performed to obtain a treatment code.

[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 canvas with rubber obtained by friction of chloroprene rubber was wound around a plain woven fabric composed of cotton yarns of warp and weft in 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 compositions shown in Table 2, kneaded with a Banbury mixer, and then rolled with a calender. The compression section contains short fibers and is oriented in the belt width direction. The short fibers were previously bonded with the RFL solution.

[0033]

[Table 2]

Next, the static and dynamic performance of the V-ribbed belt was evaluated. The results are also shown in Table 1.
FIG. 3 is a diagram showing the relationship between the cord configuration of PEN fibers (total denier number is 6,000) and cord strength, belt remaining strength, and belt strength retention. In addition, the test method of a cord and a belt is as follows.

(1) Intermediate elongation of the belt The belt is pulled at a speed of 50 mm / min.
The elongation percentage when a stress of 245 N was applied per rib was measured.

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

(3) Belt (cord) strength Pull the belt (cord) at a speed of 50 mm / min.
The maximum load when the belt (cord) was cut was obtained by dividing the maximum load by the number of ribs.

(4) Belt Residual Strength A belt is hung on a traveling tester having 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 rate The belt strength was determined by dividing the belt strength by the belt strength.

As described above, a bundle of polyester fiber filaments mainly composed of one bundle of ethylene-2,6-naphthalate is ply-twisted to make a cord, and 5 to 8 such cords are bundled and opposite to the direction of the ply twist. It can be seen that by twisting the core in the direction to form a core wire, the cord residual strength and the strength retention after belt running can be increased, and the bending fatigue property can be greatly improved. When the number of twists is less than 5, the effect of improving the bending fatigue property is small. On the other hand, when the number of twists exceeds 8, the alignment of each cord is poor, and the initial strength is low.

[0041]

As described above, according to the first aspect of the present invention, a multifilament consisting of polyester fiber filaments having ethylene-2,6-naphthalate as a main constituent unit and having a bundle of 750 to 12,000 denier is provided. The group is ply-twisted to make a cord, and 5 to 8 cords are bundled and plied in the opposite direction to the ply-twisting direction to give a total denier of 6,0.
In the core for power transmission belt which is a 00 denier twisted cord, the use of the above-mentioned core improves the flexibility of the belt, increases the residual strength of the belt after running, and increases the retention ratio of the belt. Fatigue properties can be improved, and the life thereof can be improved.

The invention according to claim 2 of the present application is characterized in that the extension portion, a cushion rubber layer in which a cord is buried along the belt longitudinal direction, and a plurality of ribs extending in the circumferential direction of the belt adjacent to the cushion rubber layer. In the V-ribbed belt comprising a compression section having the following constitution, the above-mentioned core wire is formed by twisting a multifilament group having a denier of 500 to 1,500 deniers, which is made of polyester fiber filaments mainly composed of ethylene-2,6-naphthalate. 5 to 8 cords are bundled and twisted in the opposite direction to the bottom twisting direction to give a total denier of 3,000 to 10,000 denier. 1.20 to 1.30k
N / Rib, V-ribbed belt with belt residual strength of 0.8 to 0.95 kN / rib and belt strength retention of 65 to 80%. Is improved, the belt residual strength after running and the strength retention rate are increased, and the bending fatigue property can be improved,
Its life is also improved. Further, the belt residual strength and the strength retention rate after traveling can be increased to improve the bending fatigue property, and there is an effect that it can be used as a power transmission for driving an auxiliary device such as an air conditioner or 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 view of a transmission belt core wire according to the present invention.

FIG. 3 is a diagram showing the relationship between the cord configuration of PEN fiber and cord strength, belt remaining strength, and belt strength retention.

[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 10 Child rope

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F16G 5/20 F16G 5/20 A

Claims (2)

[Claims] 1. A cord used for a power transmission belt, wherein one bundle of polyester fiber filaments comprising ethylene-2,6-naphthalate as a main constituent unit is 750 to 750.
A 12,000 denier multifilament group is ply-twisted into a strand, and 5 to 8 strands are bundled and twisted in a direction opposite to the direction of ply-twisting to give a total denier of 6,000 denier. A cord for a power transmission belt, which is a cord. 2. A V-ribbed belt comprising: an extension portion; a cushion rubber layer in which a cord is buried along a longitudinal direction of the belt; and a compression portion having a plurality of ribs adjacent to the cushion rubber layer and extending in a circumferential direction of the belt. In the above, the core wire is composed of polyester fiber filaments having ethylene-2,6-naphthalate as a main constituent unit, and one bundle comprises 750 to 750.
A 12,000 denier multifilament group is ply-twisted into a strand, and 5 to 8 strands are bundled and twisted in a direction opposite to the direction of ply-twisting to give a total denier of 6,000 denier. It is a cord and the belt strength is 1.20
1.30 kN / rib, belt residual strength 0.8-0.9
5kN / rib, belt retention rate is 65-80%
A V-ribbed belt, characterized in that: