JP2003184960A - Toothed belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toothed belt capable of holding strong adhesive force of a cable core and a rubber compound even under high temperature. <P>SOLUTION: The toothed belt A has a plurality of teeth 3 which are arranged at predetermined interval along the longitudinal direction, and a back 2 in which a cable core 1 is buried, and a tooth cloth 4 is pasted on the surface of the tooth 3. After the cable core 1 is treated with a resorcin-formalin-rubber latex mixture, it is treated with a treatment agent containing phenol resin and a nitrile group-containing high saturated polymer rubber, and the back part 2 is formed of the rubber compound 9 obtained by crosslinking the compound rubber compounding unsaturated metal carboxylate and phenol resin with a hydrogenated nitrile rubber and either organic peroxide or sulfur compound. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toothed belt covered with a tooth cloth which is used, for example, for driving a cam shaft of an automobile engine or a cam shaft and an injection pump, and for synchronous transmission of general industrial machines. It is a thing. In particular, the present invention relates to a high load belt which is improved to prevent damage to the end surface of the belt while maintaining wear resistance and tooth chipping resistance.

[0002]

2. Description of the Related Art Toothed belts for driving camshafts, injection pumps, oil pumps, water pumps, etc. of automobile engines are accompanied by an increase in engine output and an increase in load on the belts and compact engine rooms. In recent years, the use environment of the toothed belt has become particularly severe due to an increase in ambient temperature. Therefore, the toothed belts used for these are required to have further improved durability. Further, with respect to a toothed belt used for general industries, it is required to extend a replacement cycle for driving a high load such as an injection molding machine.

The failure mode of the toothed belt includes belt cutting due to bending fatigue of the core wire and crack generation due to insufficient heat resistance of rubber, and overload, insufficient heat resistance of tooth cloth and tooth rubber, and tooth wear due to wear of tooth cloth. It is roughly divided into chips. With respect to belt cutting due to bending fatigue of the core wire and insufficient heat resistance of rubber, improvements have been made in the core material, the core wire diameter, etc., and the heat resistance of the core treating agent. Also, with regard to improving the heat resistance of rubber, the number of failures has decreased due to the use of hydrogenated nitrile rubber.

[0004]

Particularly, in a toothed belt for driving an engine or an industrial drive device in which a high load is applied to the belt, the pulley shaft is bent due to the high load, and the belt runs unbalanced. Abnormal wear of the side surface of the belt due to friction with the pulley flange and the like, and cutting and tooth breakage due to damage to the side surface are likely to occur.

Further, due to the high load, the belt is stretched, the automatic tensioner does not operate, the belt is not properly loaded, and the normal operation of the engine is hindered.

With respect to these belt side wear, damage, and belt elongation, the tooth cloth material on the surface of the toothed belt that meshes with the pulley teeth is treated with a fluororesin or a layered graphite having a friction coefficient reducing effect. , The core material has been examined, but no sufficient improvement measures have been found yet.

The toothed belt generally has a core made of glass fiber, aramid fiber or the like embedded in a rubber compound by adhesive bonding, and the tooth portion is a composite covered with a canvas made of nylon fiber, aramid fiber or the like. ing. For this reason, in order to meet the above-mentioned requirements for the toothed belt, it is necessary to improve the high adhesive strength between the core wire and the rubber, especially for the toothed belt used under high load and high temperature. ing.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides a toothed belt capable of retaining a strong adhesive force between a core wire and a rubber compound even at high temperatures. The purpose is to do.

[0009]

A toothed belt according to a first aspect of the present invention for solving the above-mentioned problems includes a plurality of tooth portions arranged at predetermined intervals along a length direction and a core wire. Is a toothed belt having a back part embedded with a tooth cloth attached to the surface of the tooth part, wherein the core wire is treated with a resorcin-formalin-rubber latex mixed solution, and a phenol resin and a nitrile It has been treated with a treating agent containing a group-containing highly saturated polymer rubber, and the back has a compounded rubber in which a hydrogenated nitrile rubber is mixed with an unsaturated carboxylic acid metal salt and a phenolic resin, and an organic peroxide or a sulfur compound. It is characterized in that it is composed of a rubber compound obtained by crosslinking any one of them. With such a structure, the adhesive force between the core wire and the rubber compound forming the back part becomes strong. Further, since the phenolic resin is blended in both the core wire and the rubber compound, it is possible to prevent the adhesive force between the core fiber and the rubber compound from being lowered even at high temperatures. Here, the resorcin-formalin-rubber latex mixed solution (hereinafter referred to as “RFL solution”) used preferably has a mixing ratio of resorcin and formalin of 1: 1.5 to 3 and pH of 7 to 8, but is not limited thereto. Not something. The latex is preferably synthetic rubber.

The toothed belt according to a second aspect of the present invention is the toothed belt according to the first aspect, wherein the back portion has a mass ratio of hydrogenated nitrile rubber and unsaturated carboxylic acid metal salt of 40:60 to 50: 5.
Polymer component 10 blended with the polymer composite blended with 0 and hydrogenated nitrile rubber at 70:30 to 20:80
1 to 10 parts by mass of a phenolic resin is blended with 0 part by mass, and the rubber compound is crosslinked with an organic peroxide or a sulfur compound. According to such a configuration, the adhesive force between the rubber compound and the core wire can be made more reliable by defining the compounding amount of each rubber compound. Further, it is possible to prevent damage to the belt due to cracks and damage on the back surface of the belt that occur under high load.

The toothed belt according to a third aspect of the present invention is the toothed belt according to the second aspect, wherein 5 to 50 parts by mass of a silicic acid-based filler is mixed with 100 parts by mass of the polymer content to form an organic peroxide or It is composed of a rubber compound crosslinked with a sulfur compound. With such a configuration, the processing becomes easy and the physical properties of the rubber usable as the toothed belt for automobiles can be sufficiently exhibited. As the silicic acid-based filler used here, anhydrous silicic acid, hydrous silicic acid, calcium silicate, aluminum silicate or the like can be used.

The toothed belt according to a fourth aspect of the present invention is the toothed belt according to the second or third aspect, wherein 1 to 20 parts by mass of the short fiber is mixed with 100 parts by mass of the polymer, and an organic peroxide or sulfur is added. It consists of a rubber compound crosslinked with a compound. With this configuration, it is possible to more reliably suppress damage to the belt due to cracks or damage on the back surface of the belt that occurs under high load. Here, when the blending amount of the short fibers is less than 1 part by mass with respect to 100 parts by mass of the polymer content, the effect of blending the short fibers becomes small. Further, if compounded in an amount of more than 20 parts by mass, the Mooney viscosity of the rubber will be excessively increased, resulting in poor dispersion in the kneading process, inability to be rolled in the sheet rolling process, poor surface texture and lack of thickness, etc. Is not preferable. In addition, it becomes difficult to form the teeth with high accuracy.

A toothed belt according to a fifth aspect of the present invention is the toothed belt according to any one of the second to fourth aspects, wherein the polymer content is 10%.
1 to 10 parts by mass of a silane coupling agent is blended with 0 parts by mass, and the rubber compound is crosslinked with an organic peroxide or a sulfur compound. According to such a configuration, the adhesive force between the core wire and the rubber compound can be maintained without deteriorating the physical properties of the rubber.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION An example of an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an overall perspective schematic view of the toothed belt according to the present embodiment. In FIG.
The toothed belt A includes a plurality of tooth portions 3 arranged at predetermined intervals along the longitudinal direction, a back portion 2 continuous with the tooth portion 3, a core wire 1 embedded in the back portion 2, and a surface of the tooth portion 3. Coated tooth cloth 4
And a structure having. The back portion 2 and the tooth portions 3 form a belt body formed of the rubber compound 9. Also, the tooth cloth 4 is
The base material is a fibrous material formed by weaving a weft yarn 7 extending in the longitudinal direction of the belt and a warp yarn 8 extending in the width direction of the belt.

The rubber compound 9 constituting the belt main body is obtained by cross-linking a compounded rubber prepared by mixing a hydrogenated nitrile rubber with an unsaturated carboxylic acid metal salt and a phenolic resin, and either an organic peroxide or a sulfur compound. Has been formed.

From the viewpoint of heat resistance, the hydrogenated nitrile rubber needs to have a hydrogenation rate of at least 90% or more, preferably 92 to 98%.

The hydrogenated nitrile rubber (HNB
By mixing an unsaturated carboxylic acid metal salt with R), the tensile elastic modulus and hardness are increased. In order to secure a tensile elastic modulus, a breaking elongation, and a higher tear strength and hardness, a polymer composite in which a hydrogenated nitrile rubber and an unsaturated carboxylic acid metal salt are mixed in a mass ratio of 40:60 to 50:50. And hydrogenated nitrile rubber from 70:30
It is preferable to mix at 20:80 to obtain another polymer. As a result, it is considered that the unsaturated carboxylic acid metal salt makes the polymer component have a higher-order structure, and the unsaturated carboxylic acid metal salt forms a filler finely dispersed in the polymer component. It has a higher tensile strength than that of compounding an acid metal salt. Further, the back surface hardness of the back portion 2 can be set to 80 degrees (JIS A type hardness meter) or more. Back hardness of 80 degrees (JIS A hardness meter)
As described above, since it is preferably 85 degrees or more, deformation of the rubber can be suppressed even when stress is applied.

The unsaturated carboxylic acid metal salt is an ionic bond between an unsaturated carboxylic acid having a carboxyl group and a metal, and examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid and other monocarboxylic acids, maleic acid and fumaric acid. acid,
Dicarboxylic acids such as itaconic acid are preferable, and as the metal, beryllium, magnesium, calcium, strontium, barium, titanium, chromium, molybdenum, manganese, iron, cobalt, nickel, copper, silver, zinc, cadmium, aluminum, tin, lead, Antimony or the like can be used.

In the rubber compound 9, a phenolic resin is added to the blended polymer component. The addition amount is not particularly limited, but the addition amount of the phenol resin is preferably 1 to 10 parts by mass with respect to 100 parts by mass of the polymer content. Furthermore, 3-6 mass parts is more preferable. If the amount of the phenol resin added is less than 1 part by mass, the reliable adhesive force between the core wire 1 and the rubber compound 9 constituting the back part 2 cannot be obtained. On the other hand, if the amount is more than 10 parts by mass, vulcanization is delayed, and there is a problem that predetermined physical properties do not appear. Here, the phenol resin used includes phenol formaldehyde resin, terpene phenol resin, and alkali-phenol formaldehyde resin.
resin) and the like.

The rubber compound 9 is constituted by being compounded as described above and then crosslinked with either an organic peroxide or a sulfur compound.

The organic peroxide is not particularly limited, but may be any conventionally used one. For example, t-butyl hydroperoxide (t-buty
l hydroperoxide), 1,1,3,3 tetrabutylhydroperoxide (1,1,3,3-tetramethylbutylhydroperoxide),
p-menthane hydroperoxide
roxide), cumene hydrope
roxide), di-isopiropylbenzene hydroperoxide, di-tetra-buthyl peroxide, dicumyl peroxide, tetra-butyl cumylperoxid, 1,3
Bis (tert-butylperoxyisopropyl) benzene (1,3-bis (tert-butylperoxy isopropyl) benzen), trialkyl isocyanurate
Etc. can be mentioned.

As sulfur compounds, general sulfur and sulfur compounds are used, and as vulcanizing agents, thiurams, salt of dithiocarbates, sulfonamides, thiazols.
les) system etc. can be mentioned. Further, an organic compound, a sulfur compound and a vulcanizing agent may be used in combination.

Further, the rubber compound 9 in the present embodiment example
In addition, 5 to 50 parts by mass of a silicic acid-based filler may be added to 100 parts by mass of the polymer content described above. Preferably, 5 to 20 parts by mass is added. 5 silica filler
If it is less than the mass part, a reliable adhesive force between the core wire and the back rubber cannot be obtained. On the other hand, if it is more than 50 parts by mass, vulcanization will be delayed,
The specified physical properties do not appear. In addition, during processing, the Mooney viscosity increases, making processing difficult in the processing steps (Banbury, calendar, etc.). Here, as the silicic acid filler to be added, anhydrous silicic acid, hydrous silicic acid, calcium silicate, aluminum silicate or the like can be used.

Further, the rubber compound 9 in the present embodiment example
In addition, 1 to 20 parts by mass of short fibers can be added to 100 parts by mass of the polymer content. Here, as the short fibers, cotton, vinylon, aramid, inorganic fibers, or the like having a high melting point that does not easily melt at a low temperature during friction or having no melting point are preferable. The length is preferably 5 mm or less. When the fiber length exceeds 5 mm, the rubber is easily oriented when it is rolled into a sheet by a calender 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 belt length direction. If 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 the short fibers is more than 20 parts by mass, the Mooney viscosity of the rubber is increased and processing (poor dispersion in the kneading process, rolling in the sheet rolling process, poor surface texture and thickness, etc.) cannot be performed, and teeth are not formed. It becomes difficult to form with high accuracy.

Further, the rubber compound 9 in the present embodiment example
In addition, 1 to 10 parts by mass of a silane coupling agent can be added to 100 parts by mass of the above-mentioned polymer. Preferably, 2 to 5 parts by mass is added. If the amount of the silane coupling agent is less than 1 part by mass, the adhesive strength will decrease when calcium silicate is added. On the other hand, if the amount is more than 10 parts by mass, scorch may be generated, blooming may occur, or vulcanization may be too fast to exhibit predetermined physical properties.
Here, examples of the silane coupling agent include silane type, titanate type, and aluminum type. Preferably silane-based γ-glycidioxypropyl trimethyloxysilane (γ-glycidioxypropyltrimethoxysilane), N-β
-(Aminoethyl) -γ-aminopropyltrimethyloxysilane (N-β- (aminoethyl) -γ-aminopropyltrimet
hoxysi1ane), γ-methacryloxypropylmethyldimethylsilane
ethoxysilane) is preferred, but you don't have to stick to it. Moreover, you may use the filler which coat | covered this silane coupling agent with the silicic acid type filler.

As the core wire 1 embedded in the back portion 2 constructed as described above, glass fiber and aramid fiber are generally used. Further, any of twist cords having a composition of polybenzoxazole, polyparaphenylene naphthalate, polyester, acrylic, carbon and steel can be used. The composition of the glass fiber may be either E glass or S glass (high-strength glass), and is not limited by the thickness of the filament, the number of filaments bundled and the number of strands.

The RFL liquid for treating the core wire 1 is a mixture of resorcin / formalin initial condensate and rubber latex. The molar ratio of resorcin and formalin is preferably 1: 1.5 to 3 in order to enhance the adhesive force. The initial condensate of resorcin and formalin is mixed with the latex such 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. This latex includes styrene, butadiene,
Vinylpyridine terpolymer, chlorosulfonated polyethylene, hydrogenated NBR, epichlorohydrin, natural rubber, SBR, chloroprene rubber, olefin-vinyl ester copolymer and the like can be used.

The core wire 1 is treated with this RFL solution and then with a treating agent containing a phenol resin and a nitrile group-containing highly saturated polymer rubber. Here, as the nitrile group-containing highly saturated polymer rubber, for example, acrylonitrile-butadiene rubber (NBR) or the like can be used. The highly saturated polymer means a polymer having a high water addition rate, and in the present embodiment, a water addition rate of 80% or more, preferably 90% or more is used. Further, the amount of the phenol resin compounded in the treating agent is preferably 1 to 30 parts by mass, and more preferably 3 to 20 parts by mass, relative to 100 parts by mass of the nitrile group-containing highly saturated polymer rubber. Thus, the core wire 1
Is treated with a treatment agent containing a phenol resin nitrile group-containing highly saturated polymer rubber, the phenol resin contained in the back portion 2 is compatibilized during vulcanization, and the core wire 1 and the back portion 2 The adhesive strength is improved.

A weft yarn 7 and a warp yarn 8 which form the tooth cloth 4
As the material of the fiber material forming the, any one of nylon, aramid, polyester, polybenzoxazole, cotton, etc., or a combination thereof can be adopted. The form of the fiber may be either a filament yarn or a spun yarn, and may be a single-composition twisted yarn, a mixed-twisted yarn, or a mixed-spun yarn. Further, the woven structure may be any of twill weave, handmade weave, plain weave, and the like.

The tooth cloth 4 is preferably treated with an RFL solution, an isocyanate solution or an epoxy solution. Thus, the treated tooth cloth 4 becomes a rubber-attached canvas cloth obtained by impregnating and adhering the rubber compound 9 used for the tooth portion 3 and vulcanizing it. Specifically, after preparing a rubber lake in which the polymer component used in the rubber compound 9 is dissolved with a solvent, the rubber lake is impregnated and adhered, and dried, and then vulcanized to obtain a rubber-coated canvas. Also, an antioxidant can be added if necessary.

In addition, a reinforcing agent such as carbon black and silica, an organic peroxide, a vulcanization accelerator and the like are simultaneously mixed and blended with the polymer component used in the rubber compound 9, and a rubber paste prepared by dissolving this with a solvent is used. You can also do it. This allows the surface of the tooth cloth 4 to have lubricity.

As the solvent for dissolving the rubber compound 9, a solvent selected from methyl ethyl ketone (MEK), dimethylsulfoxide, dimethylformamide, chloroform and the like can be used. Then, the rubber paste obtained by dissolving the rubber compound 9 is applied to the tooth cloth 4,
It is preferable to impregnate and vulcanize by spraying or the like.

[0033]

EXAMPLES Next, the present invention will be specifically described with reference to examples. (Example) A rubber having the composition shown in Table 1 was kneaded by a usual method, and a rubber sheet having a predetermined thickness was prepared with a calender roll. In addition, the tooth cloth uses the fibers shown in Table 2,
The process shown in Table 2 was performed to obtain B-1. RF in Table 2
The L treatment was performed by immersing the tooth cloth in the RFL treatment liquid having the composition of C-1 shown in Table 3, drying it at 120 ° C., and then heat-treating it at 180 ° C. for 2 minutes. In addition, the rubber paste treatment in Table 2 is the same as that in the rubber compounds 1 and 2 shown in Table 4 shown in Table 3.
-2 and C-3, a toothpaste is added to a treatment liquid in which polyaryl polyisocyanate (commodity PAPI) is added as an isocyanate compound after being dissolved in MEK and toluene, and carbon black is added and mixed as an antifriction material. Was dipped and dried. In addition, each numerical value in the table is
Each part by mass is shown.

[0034]

[Table 1]

[0035]

[Table 2]

[0036]

[Table 3]

[0037]

[Table 4]

Next, the above-mentioned tooth cloth is wound around a mold having 120 teeth of ZBS tooth mold for making a belt. Then, after the core wire made of a pair of SZ twisted aramid fibers was dipped in the RFL solution shown in Table 5, it was treated with a treatment agent containing the phenol resin having the formulation 1 shown in Table 6 and the nitrile group-containing highly saturated polymer rubber. To do. The core wire was spirally wound with a predetermined tension at a pitch of 1.3 mm / piece. Next, the rubber sheets of Examples 1 to 3 and Comparative Examples 1 to 3 shown in Table 1 were attached onto the core wires, respectively. Further, after being placed in a vulcanizing can to form a tooth profile by a normal press-fitting method, it is pressure-vulcanized at 165 ° C. for 30 minutes, the back surface of the belt is ground to a certain thickness and cut into a certain width (30 mm) To obtain a running toothed belt.

[0039]

[Table 5]

[0040]

[Table 6]

The size of each of the belts produced was as follows: belt width 1
It is 5 mm, the belt tooth profile ZBS, the number of teeth is 120, and the tooth pitch is 9.525 mm, which is usually displayed as 120 ZBS30. For each belt, the adhesive strength between the core wire and the rubber is determined by JI
The measurement was performed according to SK6854. The results are summarized in Table 7.

[0042]

[Table 7]

A running test was conducted on each belt. As a running test device, a 22-tooth crank pulley 11, a 44-tooth cam pulley 13 and a 19-tooth water pump pulley 15, an eccentric pulley 19, and an idler 21 shown in FIG.
Use a test device with a layout consisting of. A running test was conducted at an effective tension of 3700 N applied to the belt at a crank pulley rotation speed of 4000 rpm and an initial tension of 350 N. Table 8 shows the results of the running test of each belt.

[0044]

[Table 8]

As can be seen from Tables 7 and 8, the inclusion of the phenolic resin in the rubber compound and the treatment liquid for the core wire makes these phenolic resins compatible with each other during vulcanization.
It can be seen that the adhesive strength is improved. Further, in Comparative Examples 1 to 3 in which the adhesive strength between the rubber compound and the core wire is less than 150 N, the belt is damaged early, whereas the rubber compounds in Examples 1 to 3 are improved. It can be seen that the belt breakage time can be greatly improved in the case of the above.

Next, using the rubber composition having the composition shown in Example 1 of Table 1, and using the treatment liquids of the compositions 1 to 4 shown in Table 6, adhesion between each core wire and the rubber composition. The force measurement results are summarized in Table 9.

[0047]

[Table 9]

[0048]

As described above, according to the present invention, the core wire is RFLed.
After the treatment, by treating with a treating agent containing a phenol resin and a nitrile group-containing highly saturated polymer rubber, the adhesive force between the rubber used for the back and the teeth and the core wire can be greatly improved. Then, by using a toothed belt in which the adhesive force between the rubber used for the back part and the tooth part and the core wire is greater than 150 N / 25 mm, the adhesive force between the belt tooth surface and the core wire generated under high load can be improved. This has an effect of preventing a defective phenomenon of tooth jump resulting from the phenomenon.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a toothed belt according to the present invention.

FIG. 2 is a schematic view of a running test device for a toothed belt.

[Explanation of symbols]

A toothed belt 1 core wire 2 back 3 teeth 4 tooth cloth 7 Weft 8 warp 9 rubber compound

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tsuyoshi Takehara             4-1-2, Hamazoe-dori, Nagata-ku, Kobe-shi, Hyogo               Mitsuboshi Belting Co., Ltd.

Claims (5)

[Claims] 1. A toothed belt having a plurality of tooth portions arranged at predetermined intervals along a length direction and a back portion in which a core wire is embedded, and a tooth cloth having a tooth cloth attached to the surface of the tooth portion. The core wire is treated with a resorcin-formalin-rubber latex mixed solution, and then treated with a treatment agent containing a phenol resin and a nitrile group-containing highly saturated polymer rubber, and the back portion is hydrogenated nitrile rubber. A toothed belt comprising a compounded rubber in which an unsaturated carboxylic acid metal salt and a phenolic resin are compounded, and a rubber compound in which either an organic peroxide or a sulfur compound is crosslinked. 2. The back has a mass ratio of hydrogenated nitrile rubber and unsaturated carboxylic acid metal salt of 40:60 to 50:50.
The polymer content of 70:30 to 20:80 of the polymer composite compounded with the above and the hydrogenated nitrile rubber is 100.
The toothed belt according to claim 1, comprising 1 to 10 parts by mass of a phenol resin and 1 to 10 parts by mass of a phenolic resin and a rubber compound crosslinked with an organic peroxide or a sulfur compound. 3. With respect to 100 parts by mass of the polymer content,
A rubber compound comprising 5 to 50 parts by mass of a silicic acid-based filler and crosslinked with an organic peroxide or a sulfur compound.
The toothed belt described in. 4. Based on 100 parts by mass of the polymer,
The toothed belt according to claim 2 or 3, wherein 1 to 20 parts by mass of short fibers are mixed and made of a rubber compound crosslinked with an organic peroxide or a sulfur compound. 5. Based on 100 parts by mass of the polymer content,
The toothed belt according to any one of claims 2 to 4, which comprises a rubber compound in which 1 to 10 parts by mass of a silane coupling agent is mixed and crosslinked with an organic peroxide or a sulfur compound.