JP2000074148A - Core wire untwining preventing method for synchronous belt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a synchronous belt with excellent bending resistance and improved in untwining of core wires at the belt side face. SOLUTION: According to this untwining preventing method applicable to a synchronous belt including teeth 3 arranged in the longitudinal direction and a back part 2 in which core wires 1 are embedded, a belt is formed and cut into a specified width and then a substance containing isocyanate compound or epoxy compound as a processing agent is applied to the core wires exposed at the belt side face and untwined, and thus the core wires 1 are consolidated with untwining precluded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing core wire fraying of a toothed belt, and more particularly, to a method for preventing core wire fraying of a toothed belt in which the core wire is frayed on the side of the belt.

[0002]

2. Description of the Related Art In recent years, toothed belts used in automobile engines have been increasing in temperature and operating environment of the toothed belts, and the load on the belts has been increasing with the increase in engine output and speed. The quality requirements for such a belt include high resistance to cracks at the base of the teeth, high abrasion resistance at the back, and high crack resistance, and excellent flexibility in the longitudinal direction of the belt. Conventional toothed belts use chloroprene rubber, chlorosulfonated polyethylene, hydrogenated nitrile rubber and other materials with better heat resistance due to changes in the usage environment. Various improvements have also been made to fabrics to improve durability.
On the other hand, as a core wire material of the toothed belt used for general industry, a glass core wire twisted with glass fiber and subjected to an adhesive treatment has been mainly used, but aramid fiber, nylon fiber or the like is used depending on the application. , Polyester fibers are used.

[0003] However, the above-mentioned fibers are liable to be frayed from the cut surface, and the core is wound around a pulley or the like from the fray of the core exposed at the side surface of the belt, and the belt is broken or the appearance is poor. Improvements have been desired for such problems. In addition, it is necessary to pack specially in order to prevent the fray from getting worse due to friction between the belts during transportation,
This contributed to the rise in costs.

[0004]

As a method of improving such fraying, for example, RFL is used as a pre-processing of a cord.
There is a method to improve the impregnation of the core bonding agent such as liquid and improve the convergence of the core.However, in order to realize a significant improvement, the amount of the processing agent attached increases and the core becomes rigid. If a belt is easily formed, the bending resistance is likely to decrease. Also,
The cost of the process improvement for improving the impregnation is high, and the cost of the belt is increased. It is also possible to improve the fraying immediately after cutting by changing the blade of the cutter to a sharp one when cutting one belt at a time from the belt sleeve, but the belts after cutting may rub each other. However, it was easily frayed by contact with the pulley flange, and did not substantially improve.

Japanese Patent Application Laid-Open No. 5-60178 describes the use of aramid fibers overcoated with rubber glue in order to improve the fraying of the cords. Certainly, the use of a core wire that has been overcoated with rubber glue as described above can slightly reduce the fraying of the core wire exposed on the side of the belt, but it is cut off because the rubber glue has not penetrated to the inside of the core wire. The fluff is hardly sufficiently improved on the side that has been set, and the diameter of the core wire is too large.
Bending resistance deteriorates because LD (distance from belt tooth bottom to center of core wire) increases, or PLD varies due to variation in the amount of rubber glue adhered to core wire, and belt and pulley mesh. Was affected. The present invention focuses on this point, and an object of the present invention is to provide a method for preventing the core wire from fraying, in which the fraying of the core wire is improved and the appearance and life are improved.

[0006]

Means for Solving the Problems In order to achieve the object,
It is an object of the present invention to improve the convergence of the core wires on the cut surface, suppress the core wires from fraying, and further improve the appearance by applying a treatment agent to the frayed core wires exposed on the side surfaces of the belt. In other words, a plurality of teeth arranged along the length direction,
In a method for preventing the core wire from fraying in a toothed belt having a back portion in which a core wire is embedded, an exposed and frayed core wire on a side surface of the belt is fixed with a processing agent. According to the first aspect of the present invention, the core wire exposed and frayed on the side surface of the belt is fixed with the treatment agent, so that the core wire exposed on the side surface of the belt can be prevented from fraying and fluffing. Further, by fixing the exposed and frayed core wire with the treatment agent, the PLD of the belt is not affected, and the bending fatigue property is not particularly reduced.

According to a second aspect of the present invention, there is provided a toothed belt in which the treating agent for fixing the exposed and frayed core wire contains 1 to 30 parts by weight of an isocyanate compound. In the method of preventing core wire fraying.
According to the method for preventing core wire fraying of a toothed belt according to claim 2, a belt containing an isocyanate compound is used as a treating agent, and the amount of the isocyanate compound is further limited to thereby increase the rigidity of the belt. The exposed and frayed core wire can be converged on the side surface.

According to a third aspect of the present invention, the treating agent for fixing the exposed and frayed core wire comprises an epoxy compound of 1 to 30.
The present invention relates to a method for preventing a core wire from fraying a toothed belt which contains a weight part. According to the toothed belt of the third aspect, a treatment agent containing an epoxy compound is used, and the treatment agent is exposed and frayed on the side of the belt without increasing the rigidity of the belt by limiting the amount of the epoxy compound. The core can be converged.

[0009]

Embodiments of the present invention will be described below. FIG. 1 shows an example of the structure of a toothed belt. On one surface of a belt back portion 2 in which a core wire 1 is embedded, a large number of tooth portions 3 are provided integrally at predetermined intervals along the longitudinal direction thereof, It is formed by sticking a tooth cloth 5 along the surface of the part 3 and the surface of the tooth bottom 4 between the teeth 3.

As the core wire 1 for reinforcing the toothed belt, an aramid fiber, which has low elongation and is excellent in bending resistance and water resistance, has recently been used as a toothed belt for driving an automobile engine. Among the toothed belts used in OA equipment and machines of various general industries, a nylon fiber or a polyester fiber made of 6-nylon is used for the core wire as a belt requiring flexibility. You.

The aramid fiber used for the cord 1 is an aramid having an aromatic ring in the main chain of the molecular structure, for example, Kevlar, Technora, Twaron, and the like.
100 to 3000 filaments of 5 to 3 deniers are collected and 1 to 5 non-twisted yarns of 100 to 3100 deniers are gathered together, and the ply twist is performed 2 to 50 times / 10 cm.
It is obtained by gathering 1 to 5 twisted yarns which have been hanged and further twisted, and twisting them with a twist number of 4 to 50 times / 10 cm. As the twisting direction, ply twisting in which reverse twisting and upper twisting are opposite to each other or rung twisting in the same direction is used.

When these fibers are used as a core wire, when the belt is cut one by one from the belt sleeve, the cut surface is frayed. Alternatively, even when no fraying occurs at the time of cutting, the side surface of the belt may rub against the flange of the pulley during running of the belt, and fraying may occur on the side surface of the belt during running.

Here, in order to prevent the above-mentioned fraying, the core wire exposed on the side surface of the belt is covered with a processing agent to converge the core wire. As a treating agent, a treating agent containing 1 to 30 parts by weight of an isocyanate compound or an epoxy compound is used,
If necessary, it may be mixed with a rubber compound. When the amount of the isocyanate compound or the epoxy compound is less than 1 part by weight, the convergence state of the fiber is deteriorated, and the fiber is left unraveled. On the other hand, when the amount exceeds 30 parts by weight, the handling of the solution becomes difficult and the workability is deteriorated. .

As the isocyanate compound used herein, for example, 4,4'-diphenylmethane diisocyanate, tolylene 2,4-diisocyanate, polymethylene polyphenyl diisocyanate, hexamethylene diisocyanate, polyaryl polyisocyanate (for example, PAPI as a trade name) ). This isocyanate compound is used by being mixed with an organic solvent such as toluene and methyl ethyl ketone. These isocyanates can be used in a mixture with a rubber compound.
It is desirable that the rubber compound be the same type as the treatment agent for the core wire, the rubber used for the back portion 2 and the rubber used for the tooth portion 3 from the viewpoint that the number of working steps does not increase, but from the viewpoint of the function of the belt, It is not necessary to use the same type. When the elastomer constituting the back portion 2 and the tooth portion 3 is polyurethane, it is not necessary to mix a rubber compound in the treating agent.

When the treating agent is of an isocyanate type, the moisture in the air acts as a crosslinking agent to be crosslinked, and the curing of the treating agent proceeds simply by coating the core wire exposed on the side surface of the belt, and the fibers are converged. This improves fraying.

When a treating agent containing an epoxy compound is used as the treating agent, a polyhydric alcohol such as ethylene glycol, glycerin or pentaerythritol, or a polyalkylene glycol such as polyethylene glycol and a halogen-containing epoxy such as epichlorohydrin may be used. Reaction products with compounds, resorcinol, bis (4
-Hydroxyphenyl) dimethylethane, phenol,
Formaldehyde resin, resorcinol. It is a reaction product with a polyhydric phenol such as formarti human resin or a halogen-containing epoxy compound. The epoxy compound is used by being mixed with an organic solvent such as toluene and methyl ethyl ketone.

Furthermore, when an epoxy compound is used, it is necessary to use an amine-based curing agent in combination, and primary and tertiary amines, which are room-temperature curing agents, are added in an amount of 5 to 30 parts by weight based on 100 parts by weight of the epoxy compound. . At this time, if the amount of the amine is less than 5 parts by weight, the crosslinking reaction does not proceed and the epoxy resin is not cured. On the other hand, when the amount of the amine exceeds 30 parts by weight, the crosslinking agent becomes rich, and the epoxy resin is cured, but physical properties for converging the fiber do not appear, and the loosening of the core wire is not improved. Examples of the primary amine include ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, m-hexamethylene-triamine, and epomate as aliphatic amines, and m-phenylenediamine, diamino-diphenyl- as aromatic amines. Methane, diamino-diphenyl-sulfone and the like are used. As the tertiary amine, triethylamine, benzyldimethylamine, aminoethyl-piperazine, or the like is used. By blending the amine in 5 to 30 parts by weight of an epoxy resin, it can be cured at room temperature and can be cured at room temperature. By applying the epoxy resin composition to the exposed core, the curing of the treating agent proceeds, and the fibers are converged to improve the fraying.

Here, as a method of applying the treatment agent, after a toothed belt is formed and cut to a predetermined width,
Using a brush on the side of the belt, a treating agent comprising the above-mentioned isocyanate compound or epoxy resin compound is attached to the brush, and the entire surface of the belt is coated with the brush. When a treatment agent containing isocyanate is applied to the side surface of the belt with a brush after being applied to the side surface of the belt, the treatment agent is allowed to stand naturally for 24 hours after application to cure the treatment agent and converge the core wire.

When an epoxy resin composition is used as a treating agent, a curing agent is mixed with the epoxy resin composition, and then the epoxy resin composition is applied to the side surface of the belt with a brush. It is also possible to accelerate the reaction by applying heat to the surface on which the treatment agent is applied, but curing at room temperature is desirable because the dimensions of the belt change.

Further, as a method of applying the treatment agent by using a machine, a method of applying the treatment agent to the side surface of the belt by using an application means is used. There is a method of spraying and applying a treating agent to the side surface, or gradually applying the treatment agent to the side surface of the belt without damaging the belt by using cotton such as sponge or gauze at the tip of the nozzle. As an application method, as long as it can be applied evenly to the side surface of the belt, either an application method while rotating the belt or an application method while moving the application means may be used. As a simple method, the belt 10 is applied as shown in FIG. After tensioning the belt by moving the pulley 9 between the pair of pulleys 9 by pulling means, the drive pulley 9 connected to the motor 19 rotates to rotate the belt 10. Then, the discharge amount and discharge time of the processing agent discharged from a sprayer (not shown) are adjusted in advance by the control means 25, and the processing agent sprayed directly to the side surface of the belt through the nozzle 15 or the oozing processing agent is passed through the sponge 17 or gauze. Apply it to the side of the belt. Here, the size of the sponge 17 is set to such a size that the entire core wire exposed by fuzzing the side surface of the belt can be applied.

The discharge amount and discharge time of the treatment agent are adjusted in advance, and when spraying directly onto the side surface of the belt, the discharge amount is set to a discharge amount sufficient to cover the exposed core wire on the side surface. When the treatment agent that has oozed from the sponge or the like is applied to the side surface of the belt, the discharge amount is reduced. At this time, the control means is adjusted so that the discharge time is extended and the processing agent can be sufficiently applied to the side surface of the belt.

The elastomer constituting the belt back portion 2 and the tooth portion 3 is a rubber composition formed by crosslinking a rubber composition or a polyurethane elastic material. The rubber composition has a hydrogenation rate of 90 to 95% by weight. Nitrile rubber 100
It is prepared by mixing 10 to 80 parts by weight of carbon black, 2 to 15 parts by weight of a plasticizer, and a crosslinking agent and other additives as necessary. Further, as the polyurethane elastic body, toluene diisocyanate and methylene diisocyanate are used as isocyanates, and as the polyol, polytetramethylene glycol, adipate and the like are used.

As a crosslinking agent, in a sulfur vulcanization system for crosslinking a rubber composition, 0.5 to 2 parts by weight of sulfur relative to 100 parts by weight of hydrogenated nitrile rubber, mercaptobenzothiazole, dibenzothiazyl disulfide, N- It is preferable to use a vulcanization accelerator such as cyclohexyl-2-benzothiazylsulfenamide, tetramethylthiuram disulfide, or tetraethylthiuram disulfide in combination. In the organic peroxide vulcanization system, 0.2 to 10 parts by weight of the organic peroxide is suitable for 100 parts by weight of the hydrogenated nitrile rubber, and 1,1-di-t-butylperoxy-
3,3,5-trimethylcyclohexane, di-t-butyl peroxide, dibutylcumyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5 -Dimethyl-2,5-di (t-butylperoxy) hexyne, 1,
Organic peroxides such as 3-bis (t-butylperoxyisopropyl) benzene and t-butylperoxyisopropyl carbonate can be used. Further, sulfur compounds, oxime nitroso compounds, monomers and polymers can be used as co-crosslinking agents. An appropriate amount of a commonly used one may be added. On the other hand, an amine-based crosslinking agent such as 3,3'-dichloro-4,4'-diaminodiphenylmethane is used as a crosslinking agent for crosslinking the polyurethane elastic body.

The tooth cloth 5 covering the teeth 3 is as follows.
A woven fabric made of aliphatic polyamide fiber (nylon fiber) such as nylon 6, nylon 6,6 or the like is generally used, which has been subjected to an adhesive treatment. A woven fabric made of an aromatic polyamide fiber (aramid fiber) having excellent wear properties is also used. As the aramid fiber, poly-paraphenylene terephthalamide, poly-metaphenylene isophthalamide, poly-paraphenylene-3,4-diphenyl ether-terephthalamide, or the like can be used. In a toothed belt using a polyurethane elastic body, it is not always necessary to cover the teeth with a tooth cloth.

The plasticizer is not particularly limited, but a trimellitic acid type, a polyether type, a polyester type, or a phthalic acid type can be used.

[0026]

The present invention will be described in more detail with reference to the following examples. Example 1 1500 in which a plurality of filament groups were converged as a core wire
Two denier yarns were set on a cool stand, and this was twisted once with a ring twisting machine at a twist number of 6/10 cm. The twisted yarn thus obtained was further 9.7.
Twisting was performed twice (twice) at a twist of 10 cm to obtain a cord.

After dipping this code in RFL shown in Table 1,
Heat treatment was performed at 00 ° C. for 2 minutes to obtain an aramid fiber cord. On the other hand, the tooth cloth was woven from the tooth cloth shown in Table 2, immersed in RFL solution, dried, and heat-treated, immersed in a rubber paste obtained by dissolving the rubber of the compounding component shown in Table 3 in a solvent, and dried to perform a surface treatment. This tooth cloth is finished by winding it into an endless cylindrical shape, and it is set on the outer periphery of a cylindrical mold formed by providing a large number of teeth forming grooves on the outer periphery. The strands were wound so as to be alternately arranged as a pair. Next, the rubber composition for a rubber-like elastic body shown in Table 3 was rolled to a thickness of 2.5 mm with a roll, wound around the core wire, and vulcanized. After vulcanization in this way, the sleeve-shaped vulcanizate is cut into a predetermined width and cut into 105S8M19 (tooth shape: S8M type, number of teeth: 10).
5. A toothed belt having a width of 19.1 mm and a tooth pitch of 8.00 mm) was obtained. At this time, fluffing of the cord was observed on the side of the belt.

[0028]

[Table 1]

[0029]

[Table 2]

[0030]

[Table 3]

Next, as shown in FIG. 2, an LM guide 21 is connected to a not-shown motor by suspending a ring-shaped toothed belt cut to a width of 19.1 mm between a pair of pulleys having 21 teeth.
To move the support plate 23 of the pulley 9 to 70 k
gf tension was applied. And pulley is 60rpm
m. Next, the time for discharging from the nozzle 15 of the sprayer was set to 30 seconds by the control device 25. The discharge amount was also set so that an appropriate amount of the processing agent was discharged from the nozzle. Then, the sprayer was turned on to discharge the treating agent, and while the belt was rotated by the apparatus as shown in FIG. 2, all portions where the core wire was exposed on the side surface of the belt were covered with the treating agent. FIG.
FIG. 3 is a schematic view of FIG. 2 viewed from the direction A. The preparation of the treatment agent was performed immediately before the application so as not to be cured before the application, and the treatment agent was filled in a sprayer. When the rotation of the motor was stopped after the treatment agent was applied to the side surface of the belt, and the belt was allowed to stand naturally for 24 hours, the treatment agent was cured, the core wire was converged, and the fluff was eliminated.

Examples 2 to 6 and Comparative Example On a belt cut from the same sleeve as in Example 1, a treatment agent having the composition shown in Table 4 was applied with a brush to the exposed core wire on the side of the belt, and allowed to stand naturally for 24 hours. Leaving was performed, and it was set as Examples 2-6 and the comparative example, respectively. Here, in the comparative example, the treatment agent was not applied to the core wire, and the appearance was fuzzy on the side surface of the belt. In the appearance, the core wire was not exposed except for the comparative example, and the treatment agent covered the core wire on the side surface of the belt sufficiently in all of the examples. However, in Example 1, the applied amount was uneven because the treatment agent was applied mechanically. In order to apply an appropriate amount of the treatment agent to the core wire on the side surface of the belt, it is preferable to apply the treatment agent mechanically as in the first embodiment. Then, the alignment (parallelism) was adjusted using a traveling tester having the layout shown in FIG. 4 so that the side surface of the belt was in contact with the pulley flange, and the belt was run for 5 hours. The load at this time was no load. Table 5 shows the results. The results in Table 5 were evaluated on a 10-point scale, and the larger the value, the better. Here, 7 or more was determined to be acceptable.

[0033]

[Table 4]

[0034]

[Table 5]

From these results, Examples 1-3 and Examples 5-6
Although there was no particular problem with respect to fraying and appearance, in the comparative example, the aramid fiber was fluffy and the progress of fraying was fast. In Example 4, there was no problem of fraying and fluffing, but the stability of the treating agent was lacking, and the pot life was short and not practical.

[0036]

As described above, according to the present invention, the core exposed on the side of the belt is exposed on the side of the belt by applying a treatment agent to the exposed core to fix the core. Since the core wires are solidified and converged, the fluff is suppressed, and furthermore, there is no fraying caused by contact with the pulley flange, thereby improving the appearance and extending the life of the belt.

[Brief description of the drawings]

FIG. 1 is a perspective view of a toothed belt in which a core wire is treated with a treatment agent by using the method for preventing a core wire from being frayed according to the present invention.

FIG. 2 is a schematic view in which a sponge is mechanically applied to the tip of a sprayer nozzle as a method for preventing core wire fraying of a toothed belt of the present invention.

FIG. 3 is a schematic view of the apparatus of FIG. 2 as viewed from a direction A.

FIG. 4 is a layout diagram showing a running test.

FIG. 5 is a perspective view of a toothed belt of a comparative example when a processing agent is not applied to a side surface of the belt after cutting.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 core wire 2 back part 3 tooth part 4 tooth bottom part 5 tooth cloth 6 treatment agent 8 driven pulley 9 drive pulley 10 toothed belt 11 tension pulley 12 driven pulley 13 flange 15 nozzle 16 application means 17 sponge 19 motor 21 LM guide 23 support plate 25 control means

Claims (3)

[Claims] 1. A method for preventing a core belt from fraying a toothed belt having a plurality of tooth portions arranged along a length direction and a back portion having a core wire embedded therein, after forming the belt and cutting the belt to a predetermined width. A method for preventing core wire fraying of a toothed belt, comprising applying a treatment agent to the core wire exposed and frayed on the side surface of the belt and fixing the processing agent. 2. The method according to claim 1, wherein the treating agent for fixing the exposed and frayed core wire contains 1 to 30 parts by weight of an isocyanate compound. 3. The method according to claim 1, wherein the treatment agent for fixing the exposed and frayed core wire contains 1 to 30 parts by weight of an epoxy compound.