JP2001140988A - Power transmission belt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power transmission belt having a prolonged service life by improving bending performance of a belt by laminating an extensible canvas on the back surface of the belt. SOLUTION: In a V-ribbed belt 1, a compression rubber layer 4 is arranged adjacent to an adhesive rubber layer 3 in which core wires 2 are embedded along the belt longitudinal direction, and a canvas 5 is laminated on the back surface of the belt. The canvas 5 to be laminated on the back surface of the belt is a knitted fabric, and a cylindrical weft-knitted fabric is arranged with the cylindrical shape so that the course direction of the knitted fabric may be the belt circumferential direction.

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 V-ribbed belt, a low-edge V-belt, and the like.
In a power transmission belt such as a flat belt, an elastic canvas is laminated on the back of the belt to improve the flexibility of the belt and improve the life of the belt.

[0002]

2. Description of the Related Art There is a V-ribbed belt as a transmission belt having a canvas. Japanese Patent Application Laid-Open No. Hei 4-151048 discloses a compressed rubber layer having a plurality of ribs extending in parallel with the longitudinal direction of the belt and having a plurality of ribs in a parallel state, a cushion layer having a core wire made of a rope buried thereon, and a back surface thereon Discloses a V-ribbed belt having a structure in which a sewing cloth joined with a sewing machine is adhered to the V-ribbed belt. This canvas is originally provided to maintain the vertical crack resistance of the belt, and is obtained by subjecting a plain woven fabric in which warp and weft yarns are woven to rubberization treatment.

Conventionally, a woven fabric widely used as a back canvas for a V-ribbed belt is a plain woven fabric having a crossing angle of 90 degrees between a warp and a weft, which is mechanically treated, that is, subjected to a tenter treatment so that both yarns are arranged in the longitudinal direction of the belt. Wide angle processing crossed at 120 degrees. The basic construction of this canvas is a canvas in which the number of belt drivings is 10 or more / 10 mm for both warp and weft, and the single yarn tensile force is 9 N or more / 10 cotton fiber yarns.
The plain fabric is forcibly subjected to a wide angle treatment, that is, a tenter treatment, with a spun yarn of 0%, so that the number of belts to be driven is 14 or more / 10 mm for both the warp and the weft.

[0004] In addition, a belt-like woven fabric having a plurality of cords arranged on the back of the belt in the width direction has improved the flexibility of the belt.

[0005]

However, the canvas subjected to the wide-angle treatment is a plain woven fabric in which the warp and the weft intersect at 90 degrees.
A method of increasing the crossing angle between the warp and the weft by cutting the spliced fabric in the degree direction and joining it together, or performing a tenter treatment on a plain woven fabric in which the warp and the weft cross at 90 degrees, and continuing the woven cloth in the 45 degree direction In each case, it took a lot of time to make a wide angle canvas.

Further, when the cord of the woven fabric is arranged in the width direction of the belt, the rubber oozes out from the gap between the cords, and in a usage mode in which the pulley comes into contact with the back of the belt, a rubber adhesive adheres to the back of the belt. This was a major problem that caused pronunciation.

The present invention addresses such a problem. In a power transmission belt such as a ribbed belt, a low-edge V-belt, and a flat belt, an elastic canvas is laminated on the back of the belt to improve the flexibility of the belt. It is another object of the present invention to provide a power transmission belt whose life is improved.

[0008]

That is, according to the first aspect of the present invention, a compression rubber layer is disposed adjacent to an adhesive rubber layer in which a core wire is embedded along the longitudinal direction of the belt, and a canvas is laminated on the back of the belt. In the power transmission belt described above, the canvas laminated on the back of the belt is a knitted fabric, and the power is disposed such that the course direction of the knitted fabric is the belt circumferential direction while the cylindrical weft knitted fabric remains cylindrical. In the transmission belt, the stretchability of the belt is improved, the flexibility is improved, the life of the belt is improved, and the tubular canvas used for the belt can be finished in a short time.

According to a second aspect of the present invention, there is provided a power transmission belt in which a knitted fabric is treated only by resorcin-formalin-latex treatment.

According to the invention of claim 3 of the present application, there is provided a power transmission belt in which the yarn used in the knitted fabric contains at least cotton fiber.

In the invention according to claim 4 of the present application, the power transmission belt includes an adhesive rubber having a core buried along the belt longitudinal direction and a compressed rubber layer having at least one rib portion along the belt longitudinal direction. It is in the power transmission belt specified as the V-ribbed belt.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A V-ribbed belt 1 shown in FIG.
A core wire 2 made of a high-strength, low-elongation cord made of polyester fiber, aramid fiber, or glass fiber is embedded in an adhesive rubber layer 3, and a compression rubber layer 4 as an elastic layer is provided below the core wire. are doing. The compressed rubber layer 4 is provided with a plurality of rib portions 7 having a substantially triangular cross section extending in the longitudinal direction of the belt, and a knitted fabric treated with resorcinol-formalin-latex (RFL) as the canvas 5 is provided on the belt surface. .

The knitted fabric is a weft knitted flat knitted tubular body, and is used so that the course direction is the belt circumferential direction.
Also, there is no distinction between front and back, and rubber knitting or pearl knitting may be used. As the yarn to be used, a single yarn of 5 to 40 count or a yarn obtained by twisting a plurality of yarns is used, but it is also possible to use a cotton fiber alone or a blended or mixed twist with another synthetic fiber such as polyamide, polyester, rayon, or acrylic.

The above-mentioned knitted fabric is bonded by RFL treatment to harden the canvas, and prevents wrinkling of the tubular knitted fabric in the spinning process. The RFL treatment is performed by dipping in the RFL solution for 0.1 to 20 seconds, and then drying at 100 to 200 ° C. for 30 to 600 seconds. Of course, rubber glue can be attached to the RFL-treated canvas.

The RFL solution used here is a mixture of an initial condensate of resorcinol and formalin and a rubber latex. In this case, the molar ratio of resorcinol to formalin should be 1: 0.5 to 3 to obtain an adhesive force. It is suitable for increasing the value. The initial condensate of resorcinol and formalin is
This is mixed with the latex so that the resin content is 10 to 100 parts by weight with respect to 100 parts by weight of the rubber content of the latex, and the total solid content is adjusted to a concentration of 5 to 40%. In some cases, a carbon black liquid is appropriately mixed with the RFL liquid to blacken the treated material. Also, RF
It is advisable to add 0.1 to 1.0% by weight of a known surfactant to the L liquid.

The latex is styrene-butadiene-
Vinylpyridine terpolymer, chlorosulfonated polyethylene, hydrogenated nitrile rubber, epichlorohydrin,
Latex such as natural rubber, SBR, chloroprene rubber, olefin-vinyl ester copolymer, and EPDM.

As the polymer used for the compressed rubber layer 4, hydrogenated nitrile rubber, chloroprene rubber, natural rubber, CSM, ACSM, SBR, ethylene-alpha-olefin elastomer is used, and hydrogenated nitrile rubber is hydrogenated. It is preferably at least 90% in order to exhibit heat resistance and ozone resistance characteristics. Hydrogenated nitrile rubber with a hydrogenation rate of less than 80%
Heat resistance and ozone resistance are extremely reduced. Considering oil resistance and cold resistance, the amount of bound acrylonitrile is 20 to 4
A range of 5% is preferred. Among them, an ethylene-alpha-olefin elastomer having oil resistance and cold resistance is preferable.

A typical example of the above-mentioned ethylene-alpha-olefin elastomer is EPDM, which is an ethylene-propylene-diene monomer. Examples of diene monomers include dicyclopentadiene, methylene norbornene, ethylidene norbornene, 1,4-hexadiene, cyclooctadiene, and the like. In addition, ethylene-propylene rubber (EP
R) can also be used.

For crosslinking the rubber, sulfur or an organic peroxide is used. Examples of the organic peroxide include dicumyl peroxide, di-t-butyl peroxide, t-butylcumyl peroxide, and benzoyl peroxide. ,
1,3-bis (t-butylperoxyisopropyl) benzene, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3,2,5-dimethyl-2,5-
(Benzoylperoxy) hexane, 2,5-dimethyl-2,5-mono (t-butylperoxy) hexane, and the like. This organic peroxide is used alone or as a mixture in the range of 0.005 to 0.02 mol g per 100 g of the ethylene-alpha-olefin elastomer.

Further, by blending a crosslinking aid (co-agent), the degree of crosslinking can be increased to prevent problems such as adhesive wear. Examples of the crosslinking aid include TIAC, TAC, 1,2 polybutadiene, metal salts of unsaturated carboxylic acids, oximes, guanidine, trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate, NN′-m- It is usually used for peroxide crosslinking such as phenylene bismaleimide and sulfur.

If necessary, other ordinary rubbers such as carbon black, reinforcing agents such as silica, fillers such as calcium carbonate and talc, plasticizers, stabilizers, processing aids, and coloring agents. What is used in the formulation is used.

The compressed rubber layer 4 is mixed with short fibers of nylon 6, nylon 66, polyester, cotton, and aramid to improve the lateral pressure resistance of the compressed rubber layer 4 and to be in contact with the pulley. The short fibers protrude from the surface of the compressed rubber layer 4 to reduce the friction coefficient of the compressed rubber layer 4 and reduce noise during belt running. Of these staple fibers, aramid staple fibers having rigidity, strength and abrasion resistance are most effective.

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.
In mm, the amount is 1 to 30 parts by weight per 100 parts by weight of the ethylene-alpha-olefin elastomer. The aramid fiber is an aramid having an aromatic ring in its molecular structure, such as, for example, Conex, Nomex, Kevlar, Technora, Twaron and the like.

When the amount of the aramid short fibers is less than 1 part by weight, the rubber of the compressed rubber layer 4 tends to stick and wears out. It is not evenly dispersed in rubber. However, the addition of this aramid short fiber is not essential, and may be the one to which short fibers made of other materials are added.

As the cord 4, polyester fiber,
Aramid fiber and glass fiber are used, and among them, a cord obtained by twisting a polyester fiber filament group having ethylene-2,6-naphthalate as a main constituent unit and having a total denier of 4,000 to 8,000 is a belt. It is preferable because the slip ratio can be reduced and the life of the belt is extended. The twist number of this cord is 10-23 / 1
0 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 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. . 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 wire 4 is subjected to an adhesive treatment for the purpose of improving the adhesiveness with rubber. As such an adhesive treatment, it is common to immerse the fiber in a resorcinol-formalin-latex (RFL) solution and then heat and dry to form an adhesive layer uniformly on the surface. However, after pretreatment with an epoxy or isocyanate compound without being limited to this,
There is also a method of 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.

On the other hand, the same kind of rubber as the compressed rubber layer 4 is used for the adhesive rubber layer 3 because it has heat resistance. However, short fibers are not mixed in, but if necessary, carbon black, a reinforcing agent such as silica, a filler such as calcium carbonate and talc, a plasticizer, a stabilizer, a processing aid, a normal coloring agent such as a coloring agent. What is used for rubber compounding is used.

A typical method for producing a V-ribbed belt is as follows. First, after wrapping a canvas and an adhesive rubber layer around the peripheral surface of a cylindrical forming drum, a cord made of a rope is spirally spun on this, and then an adhesive rubber layer and a compressed rubber layer are sequentially wound. After obtaining the laminate, it is crosslinked to obtain a sleeve.

Next, the bridging sleeve is hung on a driving roll and a driven roll, and is run under a predetermined tension. Further, the rotated grinding wheel is moved so as to abut the running bridging sleeve, and the bridging sleeve is moved. 3 to 100 on the compressed rubber layer surface
The plurality of groove portions are polished at a time.

The bridging sleeve obtained in this manner is removed from the driving roll and the driven roll, and the bridging sleeve is hung on another driving roll and the driven roll to run, cut to a predetermined width by a cutter, and individually cut. Finish the V-ribbed belt.

Further, in the present invention, in addition to the above-mentioned V-ribbed belt, as shown in FIG. 2, a low-edge V-belt 8 having canvas attached only to the upper and lower surfaces of the belt is also included. The belt 8 has a core wire 2 embedded in an adhesive rubber layer 3 and a compression rubber layer 4 as an elastic body layer below the core wire 2. Cogs may be provided on the compressed rubber layer 4 at predetermined intervals along the longitudinal direction.

[0034]

The present invention will be described in more detail with reference to the following examples. Examples 1 and 2 In the V-ribbed belt manufactured in this example, a tubular knitted fabric having a canvas structure shown in Table 2 was treated with an RFL solution (vinylpyridine latex (40%): 244 parts by weight, resorcinol 1).
1 part by weight: 37% formalin 16.2 parts by weight: sodium hydroxide 0.3 part by weight: water 299.5 parts by weight: carbon dispersion (28%): 41 parts by weight) is impregnated with an adhesive and dried. To give a treated knitted fabric.

Total densities of 1,000 denier ethylene-2,6-naphthalate fiber (PEN fiber) twisted in a 2 × 3 twist configuration with an upper twist coefficient of 3.0 and a lower twist coefficient of 3.0 as a core wire. A denier 6,000 cord subjected to an adhesive treatment was used.

Table 1 shows the compression rubber and the adhesive rubber layer, respectively.
, Kneaded with a Banbury mixer and then rolled with calender rolls. The compressed rubber layer contains short fibers and is oriented in the belt width direction.

[0037]

[Table 1]

The method of manufacturing the V-ribbed belt is a normal method. First, one ply of the tubular canvas is inserted as a canvas into a drum, and then an adhesive rubber layer is wound thereon, and the cord is spun and further compressed. After disposing the rubber layer, a crosslinking jacket is inserted over the compressed rubber layer. Next, the mold was placed in a vulcanizing can and crosslinked, and then the tubular crosslinked sleeve was removed from the mold. The compression rubber layer of the removed sleeve was formed into a rib by a grinder, and cut into individual belts from the formed body. The obtained V-ribbed belt is a K-type 3-ribbed belt having a length of 1,000 mm according to the RMA standard, a rib pitch of 3.56 mm and a rib height of 2.
0 mm, belt thickness 4.3 mm, rib angle 40 °.

The running life of the V-ribbed belt obtained as described above was evaluated for the running life of the belt, the time from the RFL treatment of the used canvas to finishing to the tubular knitted fabric, the strength of the canvas, the elongation at the time of cutting, and the like. . Table 2 shows the results. The strength of the canvas and the elongation at the time of cutting were measured for the tensile strength and the elongation in the longitudinal direction of the belt in accordance with JIS L1096 for the RFL-treated canvas.

The running test machine used for the evaluation of the endurance running test includes a driving pulley (120 mm in diameter), a driven pulley (120 mm in diameter), and an idler pulley (85 m in diameter).
m) and a tension pulley (diameter: 45 mm). A belt is hung on each pulley of the testing machine, the ambient temperature is 120 ° C., the number of rotations of the driving pulley is 49.
The driven pulley was driven at 12 horsepower at 00 rpm, and the tension pulley was run with an initial tension of 559 N / 3 rib.

The idler pulley is engaged at the back of the V-ribbed belt 1, and its wrapping angle is about 120 degrees. According to this running test method, the time until cracks occurred in the rib portions of the belt was measured.

Comparative Example 1 Both warp and weft (cotton 20 ^S / 2), warp density 75
After processing with a plain weave RFL solution having a density of 5/5 cm and a weft density of 75/5 cm and a crossing angle between the warp and the weft of 90 degrees, this plain fabric is cut into a predetermined length in a direction perpendicular to the warp and the sewing machine. Jointed into cylindrical canvas. Otherwise, a V-ribbed belt was manufactured in the same manner as in Example 1. The running life of the belt, the preparation time of the canvas, the strength of the canvas, the elongation at the time of cutting, and the like were evaluated by the durability running test of the V-ribbed belt thus obtained. The results are shown in Table 2.

[0043]

[Table 2]

As is evident from the results in Table 2, in the example, the canvas preparation time can be shortened, and the running time of the belt is not inferior.

[0045]

As described above, according to the present invention, the canvas to be laminated on the back of the belt is a knitted fabric, and the course of the knitted fabric is the belt circumferential direction while the cylindrical weft knitted fabric remains cylindrical. The belt for power transmission is arranged in such a way that the elasticity of the belt is improved and the flexibility is improved, the life of the belt is improved, and the tubular canvas used for the belt can be finished in a short time. There is an effect that can be done.

[Brief description of the drawings]

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

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

FIG. 3 shows a schematic view of a knitted fabric used in an example of the present invention.

FIG. 4 is a schematic view of a plain weave used in a comparative example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 V-ribbed belt 2 core wire 3 adhesive rubber layer 4 compressed rubber layer 5 canvas 7 rib

Claims (4)

[Claims] 1. A power transmission belt in which a compression rubber layer is disposed adjacent to an adhesive rubber layer in which a cord is embedded along a longitudinal direction of a belt, and a canvas is laminated on the back of the belt. Is a knitted cloth, and the power transmission belt is arranged such that the course direction of the knitted cloth is the belt circumferential direction while the cylindrical weft knitted cloth is kept cylindrical. 2. The power transmission belt according to claim 1, wherein the knitted fabric is treated only by resorcin-formalin-latex treatment. 3. The power transmission belt according to claim 1, wherein the yarn used in the knitted fabric contains at least a cotton fiber. 4. The power transmission belt is a V-ribbed belt comprising an adhesive rubber having a core buried along the belt longitudinal direction and a compressed rubber layer having at least one rib portion along the belt longitudinal direction. The power transmission belt according to 1, 2, or 3.