JP2003314622A - Toothed belt and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toothed belt and its manufacturing method capable of enhancing the anti-abrasiveness and the resistance against cracking even in the high load operation by heightening the hardness of the tooth part, suppressing the vibration when teeth are in engagement, and hindering noise emission from the teeth in engagement. <P>SOLUTION: The toothed belt 1 is equipped with a plurality of tooth parts 2 arranged at a certain spacing in the longitudinal direction and a back rubber layer 4 in which a core wire 3 are embedded and is structured so that a tooth cloth 5 is attached to the surface of the tooth parts 2, wherein the hardness of the rubber layer 4 is greater than the tooth parts 2, and the hardness of the rubber lessens continuously from the surface of the back rubber layer 4 to the surface of the tooth parts 2. <P>COPYRIGHT: (C)2004,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 and a method for manufacturing the same, and more particularly, to a toothed belt having a high hardness to provide wear resistance, crack resistance, and meshing resistance even during running under high load. The present invention relates to a toothed belt which suppresses vibration and prevents generation of abnormal noise during meshing, and a manufacturing method thereof.

[0002]

2. Description of the Related Art Toothed belts are composed of a back rubber layer using a single polymer or two kinds of polymers such as hydrogenated nitrile rubber and chloroprene, a canvas covering teeth, and a core wire embedded in the back rubber layer. There is. The required quality of such a toothed belt is that it is excellent in crack resistance at the tooth base, abrasion resistance and crack resistance in the back rubber portion, and excellent flexibility in the longitudinal direction of the belt.

In the conventional structure, since the load applied to the toothed belt has increased in recent years, its life has become a problem. In particular, the rubber layer is used for the tooth and back rubber layers, but the required performance for the tooth and back rubber layers is different. That is, it is better that the back rubber layer has a certain degree of hardness in order to improve wear resistance, but if the hardness of the teeth is increased, abnormal noise or vibration may occur during meshing, so if a single rubber is used, It is difficult to satisfy both.

[0004] For example, in Japanese Patent Laid-Open No. 2-113045, short fibers are put in the rubber layer of the tooth to increase the strength of the tooth, and in Japanese Patent No. 3,200,088, the rubber layer of the back is formed. And the characteristics of the rubber composition used for the tooth side rubber layer in contact with this are changed so that the chlorine content in the back rubber layer is 15 to 3
Chlorosulfonated polyethylene rubber composition having 0 to 40% by weight of chlorosulfonated polyethylene rubber composition to impart heat resistance, cold resistance and mechanical strength, and a tooth rubber layer having a chlorine content of 32 to 45% by weight. Alternatively, a hydrogenated nitrile rubber composition is used to maintain oil resistance, whereby a balanced toothed belt having excellent heat resistance and cold resistance without deteriorating oil resistance is disclosed.

It has also been proposed to change the rubber hardness by changing the degree of cross-linking between the tooth portion and the back rubber layer.

[0006]

However, if the co-crosslinking property at the interface between the tooth part and the back rubber layer is poor, there is a risk of problems such as peeling at that part. When two types of rubber layers are laminated or a rubber layer having an extremely different hardness is laminated, the hardness distribution in the thickness direction is not continuous,
There is also a problem that the stress at the interface becomes non-uniform, that is, the stress concentrates at the interface, promotes the occurrence of peeling and toothing, and affects the life.

The present invention solves such a problem by increasing the hardness of the teeth to suppress wear resistance, crack resistance, and vibration during meshing even during running under high load. An object of the present invention is to provide a toothed belt which prevents generation of abnormal noise during meshing and a method for manufacturing the toothed belt.

[0008]

That is, the invention according to claim 1 of the present application has a plurality of tooth portions arranged at predetermined intervals along the length direction, and a back rubber layer in which a core wire is embedded. The toothed belt has a tooth cloth adhered to the surface of the tooth portion, wherein the hardness of the back rubber layer is greater than that of the tooth portion, and the hardness of the rubber is continuous from the surface of the back rubber layer to the tooth surface. It is on the toothed belt that has dropped. The back rubber layer has high hardness, which improves wear resistance and crack resistance, and the tooth part has relatively low hardness, which has the effect of suppressing vibration during meshing and reducing the occurrence of abnormal noise. Furthermore, since the rubber hardness changes continuously, the stress distribution also becomes continuous, and it is possible to avoid interfacial peeling due to the shearing force between the tooth and back rubber layers, even when used in a high load environment. Belt life is also extended.

According to the second aspect of the present invention, the back belt rubber layer has a hardness of 75 to 80 and the tooth portions have a hardness of 65 to 70.

In the invention according to claim 3 of the present application, a core wire is embedded between a tooth portion provided at a predetermined interval along the length direction and a back portion provided on the opposite side, and the surface of the tooth portion is embedded. In the method for manufacturing a toothed belt coated with a canvas, a cylindrical canvas is pushed into a mold groove, a cord made of a cord is spun on the cylindrical groove, and 100 parts by mass of rubber is further coated with 1 to 2 organic peroxides. An unvulcanized rubber sheet made of a rubber composition containing 1 part by mass and 2.5 parts of an organic peroxide by 100 parts by mass of the rubber.
To 3.5 parts by mass of the rubber composition are laminated, and the unvulcanized rubber sheet is laminated, and the unvulcanized rubber is vulcanized and molded so as to be poured into the mold groove to produce a belt sleeve. A method of manufacturing a toothed belt comprising steps.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a front view of a toothed belt according to the present invention. The toothed belt 1 has a plurality of tooth portions 2 and groove portions 7 alternately arranged along a belt longitudinal direction (arrow in the figure). It has a back rubber layer 4 in which a core wire 3 made of a glass fiber cord or an aramid fiber cord is embedded, and a tooth cloth 5 is attached to the surface of the tooth portion 2 and the surface 9 of the groove portion 7.

In the present invention, however, the cross-linking density of the back rubber layer 4 is increased by adding more organic peroxide of the rubber composition used for the back rubber layer 4 than the rubber composition used for the teeth 2. The rubber hardness can be increased, and the rubber hardness can be continuously increased from the tooth surface to the surface of the back rubber layer. The toothed belt is formed by winding a tooth cloth around a mold, spinning a core wire, and then laminating an unvulcanized rubber composition for molding the tooth portion 2 and an unvulcanized rubber composition for molding the back rubber layer 4. It can be obtained by a winding method in which the above rubber sheet is wound, heated and pressed, and the rubber composition is poured into the tooth portion 2 and vulcanized. At this time, the rubber hardness is continuously measured from the surface of the tooth portion to the surface of the back rubber layer. To rise.

The amount of the organic peroxide added to the rubber composition used for the back rubber layer 4 is 2.5 with respect to 100 parts by mass of the rubber.
To 3.5 parts by mass, and the addition amount of the organic peroxide in the rubber composition used for the tooth part 2 is 1 to 2 parts by mass with respect to 100 parts by mass of the rubber, and the addition amount of the organic peroxide. Always has a large amount of back rubber layer 4.

As described above, since the back rubber layer 4 has high hardness, abrasion resistance and crack resistance are improved, and the tooth portion 2 has
Since the hardness is relatively low, it has the effect of suppressing vibration during meshing and reducing the occurrence of abnormal noise.Furthermore, since the rubber hardness changes continuously, the stress distribution also becomes continuous,
Interfacial peeling due to shearing force between the tooth portion 2 and the back rubber layer 4 can be avoided, and the belt life is extended even when used in a high load environment.

The rubber composition used for the tooth portion 2 and the back rubber layer 4 is obtained by adding a metal salt of unsaturated carboxylic acid to hydrogenated nitrile rubber, chlorosulfonated polyethylene (CSM), alkylated chloro. Rubbers having improved heat aging resistance such as sulfonated polyethylene (ACSM) and chloroprene rubber are preferable. Hydrogenated nitrile rubber has a hydrogenation rate of 80% or more, and 90% or more is preferable in order to exhibit heat resistance and ozone resistance. A hydrogenated nitrile rubber having a hydrogenation rate of less than 80% has extremely low heat resistance and ozone resistance.

When hydrogenated nitrile rubber is used,
A polymer composite obtained by blending hydrogenated nitrile rubber and unsaturated carboxylic acid metal salt in a mass ratio of 40:60 to 50:50 and hydrogenated nitrile rubber in a blend of 70:30 to 20:80 is used. It

A polymer composite obtained by mixing an appropriate amount of hydrogenated nitrile rubber and a metal salt of unsaturated carboxylic acid and polymerizing it can be a rubber composition having excellent heat resistance, strength and abrasion resistance, The hydrogenated nitrile rubber is not particularly limited, but the Mooney viscosity (ML
It is preferable that _{1 + 4} (100 ° C.)) is from 50 to 90 in order to improve the mechanical strength and lateral pressure rigidity, and also to improve the flexibility and workability.

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 monocarboxylic acids such as acrylic acid and methacrylic acid, maleic acid and fumaric acid. Acids, preferably dicarboxylic acids such as itaconic acid, as the metal 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 mass ratio of hydrogenated nitrile rubber to unsaturated carboxylic acid metal salt is 40:60 to 50:50. Although the reason is not clear, it is considered that the unsaturated carboxylic acid metal salt makes the polymer composite have a higher-order structure, and the unsaturated carboxylic acid metal salt forms a finely dispersed filler in the polymer composite, and it is thought that the hydrogen hydride is present from the beginning. It has a higher tensile strength than that of compounding an unsaturated carboxylic acid metal salt with a modified nitrile rubber.

In the above rubber composition, 10 to 30 parts by mass of silica is added to 100 parts by mass of the blended polymer. If the amount of silica is less than 10 parts by mass, the adhesive strength with the core wire will decrease. If it exceeds 30 parts by mass, the viscosity of the compound will be excessively increased, resulting in poor workability, or when the toothed belt is molded and vulcanized, the rubber will not be sufficiently pressed into the teeth.

In addition to the above rubber composition, carbon black, nylon, cotton, reinforcing agents such as short fibers such as meta-aramid fibers, para-aramid fibers and inorganic fibers, organic peroxides, vulcanization accelerators, etc. Is compounded.

The organic peroxide is usually rubber,
Di-t-butylperoxide, dicumylperoxide, t-butylcumylperoxide, 1.1-t-butylperoxy-3.3.5 used for resin crosslinking.
-Trimethylcyclohexane, 2.5-di-methyl-
2.5-di (t-butylperoxy) hexane, 2.5-
Di-methyl-2.5-di (t-butylperoxy) hexane-3, bis (t-butylperoxydi-isopropyl)) benzene, 2.5-di-methyl-2.5-di (benzoylperoxy) hexane, t -Butyl peroxybenzoate, t-butyl peroxy-2-ethyl-hexyl carbonate and the like are used.

When the toothed belt 1 is used under the condition that the tension and the tension are large together with the load, the tooth cloth of the conventional toothed belt abnormally wears and cracks occur at the root portion relatively early, resulting in a life loss due to tooth loss. Therefore, it is necessary to reinforce the tooth portion 2.

The tooth cloth 5 used here is treated with an RFL solution, an isocyanate solution or an epoxy solution. The RFL solution is a mixture of latex with an initial condensate of resorcin and formalin, and the latex used here is styrene. butadiene. It is selected from vinyl pyridine terpolymer, hydrogenated nitrile rubber, chlorosulfonated polyethylene, epichlorohydrin and the like.

The RFL-treated tooth cloth 5 is a canvas with rubber that is vulcanized by impregnating and adhering the rubber composition used for the tooth portion. Specifically, after preparing a rubber paste by dissolving a rubber composition containing carbon black, a reinforcing agent such as silica, an organic peroxide, a vulcanization accelerator, etc. in a polymer content used in the tooth portion with a solvent, Is impregnated, adhered, dried and then vulcanized into a rubberized canvas. If necessary, nickel dibutyl-dithiocarbamate (NiDB
C) can also be added.

Of course, the polymer component used in the tooth portion 2 includes carbon black, a reinforcing agent such as silica, an organic peroxide,
It is also possible to use a rubber paste in which a rubber composition in which a vulcanization accelerator and the like are mixed and blended at the same time is dissolved by a solvent.

The obtained rubber composition is dissolved in a solvent selected from methyl ethyl ketone, dimethylsulfoxide, dimethylformamide, chloroform and the like to give a rubber paste, which is then impregnated and adhered to a tooth cloth by spraying or the like. It is vulcanized.

The canvas used as the tooth cloth 5 is made of a plain weave, a twill weave, a satin weave, or the like. As the weft yarns of these woven fabrics arranged in the longitudinal direction of the belt, for example, multifilament yarns obtained by converging filament raw yarns of para-aramid fiber having a denier of at least 0.3 to 1.2 denier are 20 Those containing 80% by weight are preferable.

That is, the weft yarn is a yarn containing at least a multi-filament yarn of para-aramid fiber, and the multi-filament yarn of para-aramid fiber may include a yarn made of meta-aramid fiber. The specific construction of the weft yarn is a multi-filament yarn of para-aramid fiber, a spun yarn of meta-aramid fiber, and a urethane elastic yarn, which are three kinds of yarns. In addition, other specific weft composition is a multi-filament thread of para-aramid fiber, an aliphatic fiber thread (6 nylon, 66 nylon, polyester, polyvinyl alcohol, etc.) and a urethane elastic thread. It may be twisted.

Further, 20 to 80% by weight of the total amount of wefts arranged in the longitudinal direction of the belt is a multifilament yarn of para-aramid fiber. The reason for this is that if the content is less than 20% by weight, the tensile strength of the tooth cloth in the longitudinal direction of the belt is lowered, and tooth breakage tends to occur when the belt is running under high load. This is because the rigidity of the fibers in the driving direction of the multifilament yarn becomes excessively large for the same reason as described above, and it becomes impossible to obtain a canvas having a uniform thickness.

As the warp threads of the tooth cloth 5, filament threads of para-aramid fiber, aramid fiber composed of meta-aramid fiber, polyamide threads such as 6 nylon, 6.6 nylon and 12 nylon, polyvinyl alcohol, polyester etc. Consists of. It is preferable to use a multifilament yarn in which the filament yarn of aramid fiber is a weft yarn 5 in which the filament raw yarn of para-aramid fiber is bundled so that the rigidity is balanced and the tooth cloth has a uniform thickness. However, the materials of the warp and the weft are not limited to these.

[0032]

EXAMPLES The present invention will be described in detail below with reference to examples. Examples 1 to 4 and Comparative Examples 1 to 3 As the rubber composition used for the tooth portion, the compounds shown in Table 1 were used and kneaded, and then rolled into a rubber sheet having a thickness of 3.0 mm by a calender roll.

[0033]

[Table 1]

A 140 d / 2 nylon filament yarn was used as the warp yarn, and a 140 d / 2 nylon filament yarn and a ply-twisted yarn composed of 110 D / 1 spandex were used as the weft yarns, and the weaving texture (warp 140 yarn / 3 cm, weft 100 2/3 twill canvas made of 3/3 cm) was woven. After weaving, the canvas is oscillated in water to halve the width when weaving
After shrinking to the width, the rubber composition using the polymer shown in Table 1 was immersed in a rubber paste obtained by dissolving it in methyl ethyl ketone at a predetermined ratio, dried, and then vulcanized at 153 ° C. for 30 minutes to give a value of 0. A 9 mm treated canvas was used as a tooth cloth. In this case, the canvas used the weft direction as the longitudinal direction of the belt.

Further, about 150 glass fiber filaments having a diameter of about 9 μm which are melt-spun as a core wire and surface-treated with a silane coupling agent are bundled into a strand,
The three strands are aligned and immersed in each RFL solution in Table 2, dried at 130 ° C for 2 minutes, baked at 250 to 300 ° C for 2 minutes, and then twisted in the S direction at about 12 times / 10 cm in the S direction. Prepared twisted yarn and a twisted yarn twisted in the Z direction the same number of times.

[0036]

[Table 2]

Next, 13 ply-twisted yarns in the S direction are aligned to obtain a glass fiber cord in which the ply-twisted yarns are twisted in the Z-direction at a rate of about 8 times / 10 cm. This alignment was performed to obtain a glass fiber cord having a twist number of 8 times / 10 cm in the S direction, and for each RFL liquid, a pair of RFL-treated glass fiber cords having the upper twist directions of S and Z were used. Then, in order to adhere the RFL-treated glass fiber cord to the back part, the tooth part and the tooth cloth, the rubber composition is further dissolved in a solvent, immersed in an isocyanate-added overcoat liquid, and dried to form a core fiber. I made a code.

Next, in the production of the toothed belt, the above-mentioned tooth cloth is wound around a mold having 160 teeth of S8M tooth mold, and a core wire (glass fiber, ECG150) subjected to an adhesion treatment with RFL and isocyanate of SZ twist pair. -3/13) spirally with constant pitch (2.6 mm) and constant tension (100 N /
Wrapped around). On this core wire, the rubber composition of the tooth part and the back part shown in Table 3 were laminated in order. Further, the belt size was obtained by placing it in a vulcanizer, pressurizing and vulcanizing it by a normal press-fitting method, polishing the back surface of the belt to a certain thickness and cutting it to a certain width (25 mm), and obtaining a running toothed belt. Is 105S8M1
5 (belt tooth type: STPD type, number of teeth: 105, belt width: 15 mm, tooth pitch: 8 mm).

[0039]

[Table 3]

The hardness distribution of each of the obtained toothed belts was measured. The side surface of the belt is measured by ASKER MICRO
The surface hardness was determined from the vicinity of the tooth surface to the back surface by DUROMETER (MD-1). The result is shown in FIG. As a result, it can be seen that in each of Examples 1 to 4, the surface hardness gradually and continuously increases from the vicinity of the tooth surface to the back surface. However, Comparative Example 1 had no surface hardness from the vicinity of the tooth surface to the back surface, and Comparative Example 2 had a large hardness difference between the tooth and the back.

Further, the tooth shearing force was measured as an evaluation of the tooth chipping property, and the belt strength was evaluated by a tensile test.
The toothed belt was evaluated using the toothed belt (2)
4 teeth), driven pulley (48 teeth), driven pulley (48
Tooth), driven side pulley (diameter 50 mm), and auto tensioner (diameter 50 mm).
A running test was performed at 0 ° C. and a rotation speed of 6,000 rpm to evaluate the tooth life. The pronunciation test was conducted by collecting sound with a microphone when the toothed belt was running, and the result was evaluated on a five-level scale. The higher the value, the quieter the sound is 4.0. The above is the target value.
The results are shown in Table 4.

[0042]

[Table 4]

As a result, Comparative Example 1 is a belt using the same rubber composition for the tooth portion and the back rubber layer. In Comparative Example 2, the amount of the cross-linking agent was increased in the rubber composition of the back, the tooth shearing force was small, and the running test resulted in a short running time. In Comparative Example 3, a rubber composition having a low hardness was used for the back part, and the result was the same as that of Comparative Example 1. Further, in all of Examples 1 to 4, the running test results show that the running time is significantly increased. Moreover, Example 1
It can be seen that in all four, the pronunciation level is 4 or higher, and it is difficult to pronounce.

[0044]

As described above, in the invention described in the claims of the present application, the hardness of the back rubber layer is higher than that of the teeth, and the hardness of the rubber continuously decreases from the surface of the back rubber layer to the surface of the teeth. In the toothed belt and its manufacturing method, the back rubber layer has high hardness, which improves wear resistance and crack resistance, and the tooth portion has relatively low hardness, which prevents vibration during meshing. It has the effect of reducing the generation of abnormal noise, and because the rubber hardness is continuously changing, the stress distribution is also continuous and avoids interfacial peeling due to shearing force between the tooth and back rubber layers. Therefore, it has the effect of prolonging the belt life even when used in a high load environment.

[Brief description of drawings]

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

FIG. 2 is a graph showing a hardness distribution from the tooth surface of the toothed belt side surface to the back rubber layer surface.

[Explanation of symbols]

1 toothed belt 2 teeth 3 cores 4 back rubber layer 5 tooth cloth

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4F204 AA45 AB03 AB07 AB18 AD05                       AD16 AG03 AG17 AH12 AH81                       FA01 FB01 FB11 FB22 FF01                       FF05 FF23 FF50 FG01 FG05                       FG09 FH18 FH21 FJ29 FN17                 4F213 AA45 AD04 AD16 AG17 WA03                       WA04 WA32 WA38 WA39 WA43                       WA52 WA57 WB01 WB11 WB18                       WB21 WC03 WE02 WE06 WE07                       WE16 WF01 WF05 WF37 WK01                       WK03 WW01 WW06 WW15 WW21                       WW33

Claims (3)

[Claims] 1. A toothed belt having a plurality of tooth portions arranged at predetermined intervals along the length direction and a back rubber layer in which a core wire is embedded, and a tooth cloth attached to the surface of the tooth portion. The toothed belt is characterized in that the hardness of the back rubber layer is higher than that of the teeth, and the hardness of the rubber continuously decreases from the surface of the back rubber layer to the surface of the teeth. 2. The toothed belt according to claim 1, wherein the back rubber layer has a hardness of 75 to 80 and the teeth have a hardness of 65 to 70. 3. A toothed belt in which a core wire is embedded between a tooth portion provided at a predetermined interval along the length direction and a back portion provided on the opposite side of the tooth portion, and the surface of the tooth portion is covered with canvas. In the manufacturing method, a cylindrical canvas is pushed into a mold groove, a cord made of a cord is spun on the cylindrical canvas, and rubber 1
An unvulcanized rubber sheet made of a rubber composition obtained by adding 1 to 2 parts by mass of organic peroxide to 00 parts by mass and 2.5 to 3.5 parts by mass of organic peroxide to 100 parts by mass of rubber. A tooth comprising a step of producing a belt sleeve by laminating sheets obtained by laminating unvulcanized rubber sheets made of a rubber composition, and vulcanizing and molding the unvulcanized rubber so as to flow into the mold groove portion. Belt manufacturing method.