JP2005240862A - Toothed belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toothed belt maintaining normal operation of an engine or a transmission by suppressing wear of a tooth part generated under heavy load and damage of the tooth part caused by crack of the tooth part due to wear. <P>SOLUTION: In the toothed belt A including the tooth part 3 arranged along a longitudinal direction with a predetermined interval and having rubber 9 as base material, and a back part 2 having core wire 1 embedded and having rubber 9 as base material and having tooth cloth 4 covering surface of the tooth part 3, woof 7 of the tooth cloth 4 consists of at least fluorine fiber and polyurethane elastic thread and either of nylon fiber or aramid fiber is included on an outer circumference thereof. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention prevents tooth damage caused by wear of a tooth cloth and cracking of the tooth part due to wear under high load, and these preventive measures maintain the normal operation of the engine or transmission. Concerning the belt.

  Toothed belts that drive camshafts, injection pumps, oil pumps, water pumps, etc., for automobile engines, increase the load on the belt and increase the ambient temperature as the engine room becomes more compact with higher engine output Since the use environment of toothed belts has become particularly severe in recent years, further improvement in durability is required. As for toothed belts used for general industries, those used for high load driving of injection molding machines and the like are required to extend the replacement cycle.

The failure modes of toothed belts include belt cutting from cracking due to bending fatigue of the core and poor heat resistance of the rubber, lack of heat resistance of the tooth cloth and tooth rubber, and tooth chipping due to wear of the tooth cloth. Broadly divided. With respect to belt cutting due to bending fatigue of the core wire and insufficient heat resistance of the rubber, improvement of the core wire material, the diameter of the core wire configuration, etc., and improvement of the heat resistance of the core wire treating agent have been implemented. In addition, with respect to improving the heat resistance of rubber, the use of hydrogenated nitrile rubber has reduced failures (see, for example, Patent Document 1 below).
JP 2002-168301 A

  However, a toothed belt that drives an engine or an industrial drive device in which a high load is applied to the belt causes the pulley shaft to bend due to the high load, or the belt may be offset, and the belt is caused by friction with the pulley flange or the like. Cutting and tooth chipping due to abnormal side wear and side damage are likely to occur.

  In addition, the belt is extended by a high load, the auto tensioner does not operate, an appropriate load is not applied to the belt, and a phenomenon that prevents normal operation of the engine occurs.

  In addition, for the belt side wear, damage, and belt elongation, the toothpaste material that meshes with the pulley teeth can be treated with fluororesin or lamellar graphite that has a friction coefficient reducing effect. Wire materials have been studied, but no sufficient improvement has been found yet.

  In addition, the toothed belt has a core wire made of glass fiber, aramid fiber, etc. bonded and embedded in the rubber compound, and the tooth portion is a composite covered with a canvas made of nylon fiber, aramid fiber, etc. In response to the demand for belts, the demand for high adhesive strength between the core and rubber, particularly for toothed belts used under high loads and high temperatures, is increasing.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to maintain the normal operation of an engine or a transmission device by suppressing tooth damage caused by wear of teeth and cracking of teeth caused by wear. It is to provide an attached belt.

Means and effects for solving the problems

The toothed belt of the present invention has a tooth portion based on rubber arranged at predetermined intervals along the longitudinal direction, and a back portion based on rubber embedded with a core wire, on the surface of the tooth portion. In a toothed belt coated with a tooth cloth, the weft of the tooth cloth is made of at least a fluorine fiber and a polyurethane elastic thread, and further has at least one of a nylon fiber and an aramid fiber on the outer periphery thereof.
With the above configuration, it is possible to suppress wear and damage of the belt tooth portion and belt end face wear and damage caused by movement of the belt to the pulley flange portion, which occur under a high load.

In the toothed belt of the present invention, at least the fluorine fiber and the polyurethane elastic yarn form a core fiber, and at least one of the nylon fiber and the aramid fiber forms a covering fiber that completely covers the core fiber. It is preferable that
By the said structure, since the fluorine fiber inferior to adhesive strength does not contact the adhesive surface between tooth parts, the adhesive strength of a tooth cloth and a tooth part can be improved. Further, even when the covering fiber composed of at least one of nylon fiber and aramid fiber is worn by use, the core fiber fluorine fiber appears, and the friction coefficient of the tooth cloth can be kept low.

The toothed belt of the present invention is preferably such that the tooth cloth is treated with a treatment liquid containing an antifriction material containing at least one of fluororesin powder and graphite powder.
With the above configuration, the friction coefficient of the tooth cloth can be reduced.

In the toothed belt of the present invention, the rubber is preferably a hydrogenated nitrile rubber blended with an unsaturated carboxylic acid metal salt.
With the above configuration, it is possible to suppress damage to the belt due to cracks or damage on the back surface of the belt that occurs under a high load.

  Hereinafter, an example of an embodiment of the present invention will be described. The toothed belt according to the present invention is not limited to the following embodiments.

  FIG. 1 is an overall perspective schematic view of a toothed belt A according to the present embodiment. FIG. 1 is an overall perspective schematic view of a toothed belt A according to the present embodiment. In FIG. 1, the toothed belt A is embedded in a plurality of tooth portions 3 based on rubber 9 arranged at predetermined intervals along the longitudinal direction, a back portion 2 continuous with the tooth portions 3, and the back portion 2. This is a structure having a core wire 1 and a tooth cloth 4 coated on the surface of the tooth portion 3. The tooth cloth 4 is composed of a fiber material formed by weaving weft yarns 7 extending in the longitudinal direction of the belt and warp yarns 8 extending in the width direction of the belt.

  There is no restriction | limiting in particular in the material of the rubber | gum 9 used as the base material of the tooth | gear part 3 and the back part 2, A suitable thing is suitably selected according to use conditions. In the case of toothed belts for automobile engines and various engines, H-NBR, CR, CSM, etc. having heat resistance and oil resistance are used. In addition to H-NBR, CR, and CSM, toothed belts used in general industrial machines include NBR, EPDM, ethylene propylene copolymer (EPR), SBR, isopropylene rubber (IR), and natural rubber (NR). Any of fluorine rubber, silicon rubber, etc. can be used. In the present embodiment example, rubber 9 is exemplified by a rubber compounded with H-NBR blended with an unsaturated carboxylic acid metal salt and a rubber formed by crosslinking either an organic peroxide or a sulfur compound.

  H-NBR is required to have a hydrogenation rate of at least 90% or more from the viewpoint of heat resistance, and is preferably 92 to 98%. The rubber 9 according to this embodiment is designed to increase the modulus (tensile modulus) and hardness by blending an unsaturated carboxylic acid metal salt with the H-NBR. (Elastic modulus), elongation at break, and even higher tear strength and hardness, 15-40 parts by mass of unsaturated carboxylic acid metal salt is added to H-NBR with respect to the total polymer as described above. preferable. Or 5-15 mass parts of unsaturated carboxylic acid metal salts can be mixed, and 1-20 mass parts can also be mix | blended with respect to the polymer component 100 for a short fiber.

  Here, the short fiber is preferably a high melting point that is difficult to melt at low temperatures during friction, or cotton, vinylon, aramid, inorganic fiber or the like that does not have a melting point. The length is preferably 5 mm or less. When the fiber length exceeds 5 mm, the rubber tends to be oriented when it is made into a rolled sheet with a calendar or an extruder, and when it becomes a belt, cracks are likely to occur early due to bending. The orientation direction of the short fibers is preferably the belt width direction, but may be the orientation in the belt length direction. When the blending amount of the short fibers is less than 1 part by mass, the effect of blending the short fibers does not appear. On the other hand, when the amount of short fibers exceeds 20 parts by mass, the Mooney viscosity of the rubber increases and cannot be processed (dispersion failure in the kneading process, cannot be rolled in the sheet rolling process, the surface is poor and the thickness is not increased, etc.), and the teeth Is difficult to form with high accuracy.

  If the amount of the unsaturated carboxylic acid metal salt is less than 5 parts by mass, the rubber hardness does not reach a predetermined hardness. On the other hand, if it exceeds 40 parts by mass, the rubber hardness becomes too high, the belt rigidity becomes high, the bending fatigue property is inferior, and the belt life is shortened. Thus, by using the rubber | gum which mix | blended unsaturated carboxylic acid metal salt with H-NBR, the back surface hardness of the back part 2 can be 80 degree | times (JISA type hardness meter) or more. Since the back hardness can be 80 degrees (JISA type hardness meter) or more, preferably 85 degrees or more, deformation of rubber can be suppressed even when stress is applied.

  The unsaturated carboxylic acid metal salt is an ionic bond of an unsaturated carboxylic acid having a carboxyl group and a metal. Examples of the unsaturated carboxylic acid include monocarboxylic acids such as acrylic acid and methacrylic acid, maleic acid, fumaric acid, and itacone. Dicarboxylic acids such as acids are preferred, and the metals are beryllium, magnesium, calcium, strontium, barium, titanium, chromium, molybdenum, manganese, iron, cobalt, nickel, copper, silver, zinc, cadmium, aluminum, tin, lead, antimony Etc. can be used.

  The rubber 9 is constituted by being blended with either an organic peroxide or a sulfur compound after being blended as described above.

  The organic peroxide is not particularly limited, but may be any conventionally used one. For example, t-butyl hydroperoxide, 1,1,3,3 tetrabutyl hydroperoxide, p-menthane hydroperoxide, cumene Hydroperoxide, di-isopiropylbenzene hydroperoxide, di-tetra-buthyl peroxide, dicumyl peroxide, tetrabutycumyl peroxide (tetra-) butyl cumyl peroxid), 1,3-bis (tert-butylperoxyisopropyl) benzene, and trialkyl isocyanurate.

  Sulfur compounds include general sulfur and sulfur compounds, and vulcanizing agents include thiurams, salt of dithiocarbates, sulfenamides, thiazoles, etc. I can do it. An organic compound, a sulfur compound, and a vulcanizing agent may be used in combination.

  As described above, glass fiber and aramid fiber are generally used for the core wire 1 embedded in the back portion 2 composed of the rubber 9 as a base material. Further, any of twisted cords composed of polybenzoxazole, polyparaphenylene naphthalate, polyester, acrylic, carbon, and steel can be used. The composition of the glass fiber may be any of E glass, S, U, and K glass (high-strength glass), and is not limited to the thickness of the filament, the number of bundles of filaments, and the number of strands.

  As the core wire 1, one processed by an RFL solution in which an initial condensate of resorcin and formalin and rubber latex are mixed is used. The molar ratio of resorcin to formalin is preferably 1: 1.5 to 3 in order to increase the adhesive force with the rubber 9. The initial condensate of resorcin and formalin is mixed with the latex so that the resin content is 2 to 30 parts by mass with respect to 100 parts by mass of the rubber content of the latex, and the total solid concentration is 5 to 40%. Adjusted to concentration. As this latex, styrene / butadiene / vinylpyridine terpolymer, chlorosulfonated polyethylene, H-NBR, epichlorohydrin, natural rubber, SBR, chloroprene rubber, olefin-vinyl ester copolymer and the like can be used.

  Moreover, as a material of the fiber material forming the warp 8 constituting the tooth cloth 4, any of nylon, aramid, polyester, polybenzoxazole, cotton, or a combination thereof can be adopted. 66 is preferred.

  Moreover, as a material of the fiber material which forms the weft 7 which comprises the tooth cloth 4, what includes at least one of a nylon elastic fiber and an aramid fiber in the outer periphery can be employ | adopted including at least a polyurethane elastic yarn and a fluorine fiber. In particular, it is preferable that the weft 7 is one in which a fluorine fiber and a polyurethane elastic yarn form a core fiber, and at least one of a nylon fiber and an aramid fiber forms a covering fiber that completely covers the core fiber.

  Fluorine fibers include polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkoxyethylene copolymer (PFA), and tetrafluoroethylene-ethylene copolymer. (ETFE). Fluorine fibers are used to reduce the friction coefficient of the tooth cloth 4, and specifically, the friction coefficient of the tooth cloth 4 is preferably 0.2 or less. The polyurethane elastic yarn is used to make the tooth portion 3 conform to a predetermined tooth shape when the toothed belt is formed.

The core fiber is used in a state where the polyurethane elastic yarn and the fluorine fiber are stretched in parallel while being stretched, but at least the fluorine fiber of the core fiber is preferably twisted.
The covering fiber is coated around the core fiber using a covering machine. The number of turns of the covering fiber with respect to the core fiber is not particularly limited, but the number of turns so that the core fiber is completely covered is selected in consideration of the core fiber to be used and the weaving degree of the covering fiber. In addition, when both a nylon fiber and an aramid fiber are used as a covering fiber, both are mixed and twisted. Moreover, when an aramid fiber is used as the covering fiber, heat resistance is imparted to the tooth cloth.

  As described above, by completely covering the core fiber including the fluorine fiber with the covering fiber, the fluorine fiber having poor adhesion is not exposed on the bonding surface between the tooth cloth 4 and the tooth portion 3. The adhesive strength of the tooth cloth 4 can be improved. In this case, the friction coefficient reducing effect by the fluororesin is exhibited when the covering fiber is worn and the core fiber is exposed as the belt is used.

  In addition, the form of the fibers of the weft yarn 7 and the diameter yarn 8 may be either a filament yarn or a spun yarn, and may be any one of a single composition twisted yarn, a mixed twisted yarn, or a blended yarn. Further, the weaving configuration may be any of twill weave, hand-woven, plain weave, and the like.

  This tooth cloth 4 is treated with an RFL solution, an isocyanate solution or an epoxy solution, and then subjected to a rubber paste treatment for impregnating and vulcanizing a rubber of the same quality as the rubber 9 used for the tooth portion 3. Specifically, a rubber lake is prepared by dissolving the polymer used in the rubber 9 with a solvent, impregnated and adhered, dried, and vulcanized to obtain a rubber canvas. Moreover, anti-aging agent can also be added as needed.

  As a solvent for dissolving the rubber 9, a solvent selected from methyl ethyl ketone (MEK), dimethyl sulfoxide, dimethylformamide, chloroform and the like can be used. The rubber paste obtained by dissolving the rubber 9 is preferably impregnated and adhered to the tooth cloth 4 by spraying or the like and vulcanized.

  Further, for the purpose of reducing the friction coefficient of the tooth cloth, it is preferable that at least one of a fluororesin powder and a graphite powder is added to the RFL treatment liquid or the rubber paste treatment liquid. As the fluororesin powder, one or more powders selected from PTFE, FEP, PFA, and ETFE are used. The fluororesin powder and the graphite powder may be added in an amount of 30 to 200 parts by mass, more preferably 80 to 120 parts by mass with respect to 100 parts by mass of the rubber component in the RFL treatment liquid or rubber paste treatment liquid. preferable.

According to this embodiment example having the above-described configuration, it is possible to suppress wear and damage of the belt tooth portion and belt end face wear and damage caused by movement of the belt to the pulley flange portion under high load.
Moreover, since the fluorine fiber inferior in adhesive strength does not come into contact with the adhesive surface between the tooth parts, the adhesive strength between the tooth cloth and the tooth parts can be improved. Further, even when the covering fiber composed of at least one of nylon fiber and aramid fiber is worn by use, the core fiber fluorine fiber appears, and the friction coefficient of the tooth cloth can be kept low.
Furthermore, the friction coefficient of the tooth cloth can be reduced, and further, damage to the belt due to cracks and damage on the back surface of the belt that occurs under a high load can be suppressed.

Next, the present invention will be specifically described with reference to examples.
A rubber having the composition shown in Table 1 was kneaded by a normal method, and a rubber sheet A-1 having a predetermined thickness was prepared with a calendar roll. Moreover, a tooth cloth was produced using the fibers shown in Table 2, and the tooth cloth was immersed in the fluororesin-containing RFL treatment liquid C-1 shown in Table 3, dried at 120 ° C. and heat-treated at 180 ° C. for 2 minutes. . Subsequently, rubber paste F-1 and rubber paste treatment liquid C-2 containing polyaryl polyisocyanate (trade name PAPI) as an isocyanate compound shown in Table 4, rubber containing F-2 and graphite It processed with the paste processing liquid C-3.

  Next, the above-mentioned tooth cloth was wound around a mold having 120 teeth of ZBS tooth profile for belt production, and the SZ twisted pair of RFL and hydrogenated nitrile rubber were bonded with a rubber paste dissolved in a solvent such as toluene. The core wire shown in Table 5 was wound around the spiral with a predetermined tension at the pitch shown in Table 6. The rubber sheet of Table 1 was affixed on this core wire. Furthermore, after putting into a vulcanizing can and forming a tooth profile by a normal press-fitting method, pressure vulcanization is performed at 165 ° C. for 30 minutes, and the belt back surface is polished to a certain thickness and cut to a certain width (30 mm). A toothed belt was obtained. Table 7 shows the adhesion between the tooth cloth and the rubber of the toothed belt.

  The produced belt has a belt width of 30 mm, a belt tooth profile ZBS, a tooth number of 120 teeth, and a tooth pitch of 9.525 mm, and is normally displayed as 120 ZBS30. Next, a running test of the belt was performed using the tooth cloths B-1 to B-5 in Table 2. As the running test apparatus, a test apparatus having a layout including a 22-tooth crank pulley 12, a 44-tooth cam pulley 13, a 19-tooth water pump pulley 15, an eccentric pulley 19, and an idler 21 shown in FIG. 2 is used. A running test was performed with an effective tension applied to the belt of 3700 N at a crank pulley rotational speed of 4000 rpm and an initial tension of 350 N. The remaining thickness of the root tooth cloth after running for 200 hours was evaluated. Table 8 summarizes the results of the running test for each belt.

  From Tables 7 and 8, the toothed belts (Examples 1 and 2) using the tooth fabrics B-4 and B-5 made of wefts having covering fibers that completely cover the core fibers are covered Compared to toothed belts (Comparative Examples 1 to 3) using B-1 to B-3 made of wefts without ring fibers, the residual thickness of the tooth cloth has an adhesive force with the tooth bottom. It was also recognized that it had high wear resistance.

  The present invention can be changed in design without departing from the scope of the claims, and is not limited to the above-described embodiments and examples.

1 is a schematic perspective view of a toothed belt according to the present invention. It is the schematic of the running test apparatus of a toothed belt.

Explanation of symbols

A toothed belt 1 core 2 back 3 tooth 4 tooth cloth 7 weft 8 warp 9 rubber 10 adhesive layer

Claims (5)

  A toothed belt having a tooth portion based on rubber arranged at predetermined intervals along the longitudinal direction and a back portion based on rubber embedded with a core wire, and having a tooth cloth coated on the surface of the tooth portion A toothed belt in which the wefts of the tooth cloth are made of at least fluorine fibers and polyurethane elastic yarns, and further have at least one of nylon fibers and aramid fibers on the outer periphery thereof.   The toothed belt according to claim 1, wherein at least the fluorine fiber and the polyurethane elastic yarn form a core fiber, and at least one of the nylon fiber and the aramid fiber forms a covering fiber that completely covers the core fiber.   The toothed belt according to claim 1 or 2, wherein the tooth cloth is treated with a resorcin-formalin-latex liquid containing fluororesin powder.   The toothed belt according to claim 3, wherein the tooth cloth is further treated with a rubber paste treatment liquid containing graphite powder. The toothed belt according to any one of claims 1 to 4, wherein the rubber is a hydrogenated nitrile rubber compounded with an unsaturated carboxylic acid metal salt.

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