JP2005042737A - Toothed belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toothed belt of rubber-like material such as polyurethane, in which two different kinds of glass cores, twisted in different directions, are irregularly twisted, in which the number of twisted cores and the number of twisting are limited to restrict untwisting force of the glass cores, and in which twisting force in one direction is restricted as a belt for reducing twisting defective. <P>SOLUTION: This toothed belt 1 comprises two kinds of glass cores 4, twisted in different directions, which are irregularly twisted. The glass core 4 is composed of two glass strands composed of glass filaments twisted with each other. The number of twisting in the glass strands is set at 2.5-4.0 times/inch. The number of cores in the belt is set in an even number. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００４６】
次に、上記心線を用いて、ベルト幅３．０ｍｍ、ベルト歯形ＳＴ歯形、歯数７２３、歯ピッチ１．０ｍｍ、ベルト長さ７２３ｍｍの歯付ベルトを作製した。製造方法としては、歯形状に対応した溝部を有する内金型に前記心線を所定ピッチでスパイラル状にスピニングし、そして外金型をセットした後、ウレタンプレポリマーアジプレンＬ−１００を１００質量部、アミン系硬化剤（ＭＯＣＡ）１２質量部、可塑剤（ＤＯＰ）４０質量部、触媒（アゼライン酸）０．８質量部を配合したウレタン配合物をキャビティ内に注入し、加熱硬化させて歯付ベルトを作製した。
【００４７】
得られた歯付ベルトの外観検査を行い、ねじれ不良率を算出した。そのときのねじれ不良の目安としては、ベルトに張力を付与したとき、水平から４５度以上傾いた場合、ねじれ不良とした。その結果を表２に示す。
【００４８】
【表２】

【００４９】
表１及び表２から実施例は比較例に比べて、錘が１０回転するのに要する時間が長く、撚り戻り回転数も小さく、ねじれ不良率も小さいことが判る。
【００５０】
次に、実施例２と同仕様のベルトを、ベルト幅を変量してベルト中に含まれる心線本数を変えて、静止状態でベルトのねじれ発生の有無を観察した。実施例４は心線本数が１本、実施例５は心線本数が２本、実施例６は心線本数が３本、実施例７は心線本数が４本、実施例８は心線本数を５本とした。その結果を表３に示す。
【００５１】
【表３】

【００５２】
表３の結果より、ベルト中に心線が偶数本埋設されているベルトは、全くねじれが発生しないことがわかる。
【００５３】
次に、ベルト内の心線本数を理論心線本数で小数点一桁まで求めたベルトを使用した。実施例９としては、ベルト内の理論心線本数が４．４本のもの、実施例１０としてはベルト内の理論心線本数が４．１本のものを使用した。そして、図３に示すような試験機でベルトを回転させ、デジタル変位計を用いて厚み方向の変位を計測した。そして、図４に示すように、計測された最大値、最小値よりベルト内での最大倒れ角度を算出した。このときの走行条件としては、軸荷重９．８Ｎ、回転数５００ｒｐｓであった。その結果を図５に示す。図５は、１２０本のベルトの倒れ角度と度数の関係を示したグラフであり、倒れ角度が大きい程ベルトねじれが大きくなるものである。
【００５４】
図５の結果から実施例１０は実施例９と比べて倒れ角度が小さい範囲での度数が多く、ベルト内の心線本数が偶数に近づけば近づくほどベルトねじれが発生しないことがわかる。
【００５５】
【発明の効果】
上記のように、本発明は、上記２種類のガラス心線が片撚りで、ガラスフィラメントによって構成されたガラスストランドを２本撚り合わせ、前記ガラスストランドの撚り数を２．５〜４．０回／インチとしたものであることから、耐屈曲疲労性に優れ、ガラス心線の撚り戻り力が小さく、ベルトの状態でねじれ不良を少なくすることができるという効果が有る。
【００５６】
又、請求項２に記載の発明でも上記２種類のガラス心線が片撚りで、ガラスフィラメントによって構成されたガラスストランドを３本撚りあわせ、前記ガラスストランドの撚り数が２．５〜３．７回／インチとしたものであることを特徴とする歯付ベルトとしたことから、耐屈曲疲労性に優れ、ガラス心線の撚り戻り力が小さく、ベルトの状態でねじれ不良を少なくすることができるという効果が有る。
【００５７】
請求項３に記載の発明によると、ベルト中の心線本数が偶数本である請求項１又は２に記載の歯付ベルトであることから、ベルトの状態で全くねじれが無くなるという効果が有る。
【図面の簡単な説明】
【図１】歯付ベルトの実施形態の一例を示す一部の断面図である。
【図２】心線の撚り戻り回転数等を測定した方法を示す概略図である。
【図３】ベルトの倒れ角度を測定する為の試験装置を示した概略図である。
【図４】ベルトの倒れ角度を示した概念図である。
【図５】ベルトの倒れ角度と度数との関係を示したグラフである。
【符号の説明】
１ 歯付ベルト
２ 背ゴム部
３ 歯ゴム部
４ 心線
５ 支持棒
７ 錘[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a toothed belt used in, for example, OA equipment.
[0002]
[Prior art]
In recent years, a polyurethane belt, which is said to be excellent in wear resistance and the like, is often used as a toothed belt in a drive transmission mechanism of OA equipment and precision machines. At that time, there are three types of conventional cores that are generally used as belt tensile bodies: metal wires, polyester fibers, and aramid fibers, each having the following advantages and disadvantages. .
[0003]
(1) The wire core body has both high strength and Young's modulus, and is suitable for high-load transmission. However, the disadvantage is that it is one by one from the cylindrical molded body that is an assembly of many belts in the belt manufacturing process. When each belt is obtained by cutting, it cannot be easily cut with a blade, and if a wire is exposed on the side surface of the belt, it may not be used because it rubs against the pulley flange. Furthermore, there are disadvantages such as poor dimensional (length) stability with respect to temperature and rusting.
[0004]
(2) Polyester core is inexpensive and has good dimensional stability against humidity and is suitable for light load transmission, but is not suitable for high load transmission due to its low strength, and dimensional stability to temperature There are disadvantages such as bad.
[0005]
(3) Since the aramid core is excellent in strength as in the case of the wire core, there is no difficulty in cutting as in the case of the wire core and there is no problem when exposed to the side. Widely used for high load transmission. However, the biggest drawback is that the dimensional change with respect to humidity is large, and it is also difficult to be expensive.
[0006]
In other words, the core for the polyurethane belt is required to be inexpensive, excellent in strength, and excellent in dimensional stability against temperature and humidity. In particular, in the field of home appliances and office automation equipment, since cases that are used with fixed shafts are increasing, those with little change in length are strongly demanded.
[0007]
Therefore, in order to meet the above requirements, a cord formed by twisting a polyester fiber yarn and a polyamide fiber yarn (see Utility Model Registration Document 1), a polybutylene terephthalate twisted yarn cord (see Utility Model Registration Document 2), a total fragrance Various proposals have been made, such as a group polyester fiber cord (see Patent Document 1), but these have not been put into practical use because they are all special products and inferior in strength.
[0008]
[Utility model registration document 1]
Japanese Utility Model Publication No. 58-35035
[Utility model registration document 2]
Japanese Utility Model Publication No. 59-10540
[Patent Document 1]
Japanese Patent Laid-Open No. 63-57941
As a core that can satisfy the above requirements, a glass core that is generally used as a tensile body of a rubber belt can be cited as an easily conceivable one.
[0012]
More specifically, the glass core is a twisted yarn made of glass fiber. In general, the twist coefficient is often set to 20 to 10 times / 10 cm for the purpose of imparting excellent bending fatigue resistance to the belt body during the twisting. When used as a belt tensile body, generally, two types of glass core bodies of S twist and Z twist are used, and these glass core bodies are alternately arranged in the belt width direction, resulting in the twist direction. The offset when the belt runs is canceled between the glass cores.
[0013]
Advantages of the glass core include low cost and excellent strength. In addition, it has good dimensional stability with respect to temperature and humidity, and is therefore optimal as the core of the polyurethane toothed belt. However, until now, it has not been put into practical use because of insufficient adhesive technology with polyurethane, but this point has already been solved in Patent Document 2.
[0014]
[Patent Document 2]
Special registration No. 2821369 [0015]
However, when glass fiber is used, the rigidity of the core wire is increased, and the twist return force that the applied twist tries to return is also increased. That is, in the urethane belt in which the core wires of the S twist and the Z twist are alternately embedded, the twist return force becomes large, and when the number of the core wires is an odd number, the balance of the twist return force is lost and it is likely to twist in one direction. As a result, the quality of the product deteriorated as a twisting defect.
[0016]
[Problems to be solved by the invention]
The present invention has been made in view of such various points. The purpose of the present invention is to provide two types of glass cores having different twisting directions as a single twist in a rubber toothed belt made of polyurethane or the like. By limiting the number, the twisting return force of the glass core wire is suppressed, and the belt is intended to reduce twisting defects by suppressing the force to twist in one direction.
[0017]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention has a large number of tooth rubber portions disposed at predetermined pitch intervals in the belt length direction on the inner surface side of the back rubber portion having a rectangular cross section extending in the belt length direction. And a belt body extending in the belt length direction and spaced apart from each other by a predetermined pitch in the belt width direction, and twisted in different directions. In a toothed belt provided with two types of glass cores made of glass fiber, the above two types of glass core wires are twisted together and two glass strands composed of glass filaments are twisted together to twist the glass strands. It is in a toothed belt whose number is 2.5-4.0 times / inch.
[0018]
According to the first aspect of the present invention, the two types of glass core wires are single-twisted, and two glass strands composed of glass filaments are twisted together, and the number of twists of the glass strand is 2.5-4. Since it is 0 times / inch, the bending fatigue resistance is excellent, the twisting-back force of the glass core wire is small, and the twist failure can be reduced in the belt state.
[0019]
According to the second aspect of the present invention, a large number of tooth rubber portions are disposed at predetermined pitch intervals in the belt length direction on the belt inner surface side of the back rubber portion having a rectangular cross section extending in the belt length direction. A belt body and glass each extending in the belt length direction and embedded in the belt width direction with a predetermined pitch interval in parallel with each other in parallel with each other and twisted in different directions. In a toothed belt provided with two types of fiber glass cores, the two types of glass core wires are twisted together, and three glass strands composed of glass filaments are twisted together, and the number of twists of the glass strands Is in a toothed belt having a speed of 2.5 to 3.7 times / inch.
[0020]
According to the second aspect of the present invention, the two types of glass core wires are single twisted, and three glass strands composed of glass filaments are twisted together, and the number of twists of the glass strand is 2.5-3. Since it is a toothed belt characterized by being 7 times / inch, it has excellent bending fatigue resistance, low twisting force of the glass core wire, and can reduce twisting failure in the belt state. it can.
[0021]
The invention according to claim 3 is the toothed belt according to claim 1 or 2, wherein the number of core wires in the belt is an even number.
[0022]
According to the third aspect of the present invention, since the number of core wires in the belt is an even number, the toothed belt according to the first or second aspect has no twist in the belt state.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
FIG. 1 shows a toothed belt according to the present embodiment, and this toothed belt has a belt length on the belt inner surface side (lower surface side in the figure) of a back rubber portion 2 having a rectangular cross section extending in the belt length direction. It has a belt body 1 in which a large number of tooth rubber portions 3, 3,. Each tooth rubber portion 3 has an arc shape in cross section, and smoothly meshes with the tooth portion of the toothed pulley around which the toothed belt is wound to reduce the belt running noise. .
[0024]
The back rubber part 2 has two types of glass cores that are wound in two spirals so as to extend in the belt length direction and to be arranged in parallel and alternately with a predetermined pitch interval in the belt width direction. 4s and 4z are embedded. These glass cores 4s and 4z are, for example, twisted in a state in which a plurality of glass fiber bundles made of glass filaments that are heat-treated after being immersed in an RFL treatment liquid are aligned. In the case of one glass core body 4s, the twist is applied in the S direction, and in the case of the other glass core body 4z, it is Z-twisted to form a single twist.
[0025]
And the twist coefficient of the glass cores 4s and 4z of the said S twist and Z twist sets the twist number of a glass strand to 2.5-4.0 times / inch, when two are twisted together. Here, if the number of twists is less than 2.5, the bending fatigue resistance when the belt is used is inferior, and the performance is significantly reduced during belt running. Moreover, the twist number of the glass core bodies 4s and 4z of the said S twist and Z twist sets the twist number of a glass strand to 2.5-3.7 times / inch, when three are twisted together. The number of core wires embedded in the belt is preferably an even number.
[0026]
The glass fiber cord is subjected to the following adhesion treatment.
The melt-spun monofilament is immersed in a treatment agent in which an RFL solution, an aqueous dispersion of blocked isocyanate, and an aqueous dispersion of a water-insoluble epoxy resin are mixed. This treatment is preferably performed in a false twisted state, and after the immersion treatment, it is dried in an oven and twisted to obtain a fiber cord.
[0027]
Examples of the isocyanate in the blocked isocyanate resin include monoisocyanate compounds such as hexamethylene monoisocyanate and phenyl isocyanate, hexamethylene diisocyanate, tolylene diisocyanate, diphenylmethane triisocyanate, triphenylmethane triisocyanate, butane-1,2, Examples include 2-triisocyanate, trimethylolpropane tolylene diisocyanate trimer, triisocyanate compounds such as 2,4,4′-diphenyl ether triisocyanate, and polyisocyanate compounds such as polymethylene polyphenyl isocyanate.
[0028]
As the blocking agent for blocking the isocyanate, lactams and oximes are preferably used. Specific examples of the oximes include acetooxime, methyl ethyl ketone oxime, methyl isobutyl ketone oxime, cyclohexanone oxime, and benzophenone oxime. Examples include propiolactam, petitolactam, and ε-caprolactam. As other blocking agents, lower alcohols, phenols, active methylene compounds, imides and the like can also be used.
[0029]
A blocked isocyanate compound obtained by blocking these single or two or more kinds of isocyanate compounds with these single or two or more types of blocking agents is used in the presence of a known surfactant, using a ball mill, a homogenizer, a media disperser or the like. Used by dispersing or emulsifying in water.
[0030]
The RFL solution is a mixture of resorcin and formalin condensate with the above rubber latex. In this case, the molar ratio of resorcin and formalin is preferably 3/1 to 1/3 in order to increase the adhesive force. is there. Examples of rubber latex include styrene-butadiene-vinylpyridine terpolymer, chlorosulfonated polyethylene, hydrogenated nitrile rubber, epichlorohydrin, natural rubber, SBR, chloroprene rubber, olefin-vinyl ester copolymer, EPDM, and other latexes. Can be mentioned. The initial condensate of resorcin and formalin is mixed so that the resin content is 5 to 100 parts by mass with respect to 100 parts by mass of the rubber content of the rubber latex.
[0031]
The epoxy resin is preferably water-insoluble and has two or more epoxy groups in the molecule. This is because when the water-soluble epoxy is mixed with the RFL solution, it reacts with the RF resin, and the quality of the treatment liquid and the adhesiveness are deteriorated.
[0032]
Here, the polyurethane composition constituting the belt body is obtained by casting and heating a liquid urethane raw material. Generally, as a molding method, a premix solution in which a polyol, a catalyst, a chain extender, a pigment, and the like are mixed is used. And a one-shot method in which a solution containing an isocyanate component is mixed and cast and then subjected to a curing reaction, and a prepolymer and a curing agent obtained by reacting an isocyanate and a polyol in advance and modifying a part of the isocyanate with a polyol. There is a prepolymer method in which a mixture is cast and cross-linked, but in the present invention, the prepolymer method is preferably used.
[0033]
Although it does not limit as isocyanate, aromatic polyisocyanate, aliphatic polyisocyanate, alicyclic polyisocyanate, and those modified bodies can be used. Specific examples include toluene diisocyanate (TDI), methylene didiisocyanate (MDI), xylylene diisocyanate (XDI), naphthalene diisocyanate (NDI), hexamethylene diisocyanate (HDI), and isophorone diisocyanate (IPDI). TDI and MDI are preferably used.
[0034]
Examples of the polyol include ester polyols, ether polyols, acrylic polyols, polybutadiene polyols, and mixed polyols thereof. Examples of ether polyols include polyethylene ether glycol (PEG), polypropylene ether glycol (PPG), and polytetramethylene ether glycol (PTMG). Examples of ester polyols include polyethylene adipate (PEA) and polybutylene adipate (PBA). , Polyhexamethylene adipate (PHA), poly-ε-caprolactone (PCL) and the like.
[0035]
As the curing agent, an amine compound that is a primary amine, secondary amine, or tertiary amine is used. Specifically, 1,4-phenylenediamine, 2,6-diaminotoluene, 1,5-naphthalenediamine, 4 , 4'-diaminodiphenylmethane, 3,3'-dichloro-4,4'-diaminodiphenylmethane (hereinafter referred to as MOCA) 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 1-methyl-3,5- Bis (methylthio) -2,6-diaminobenzene, 1-methyl 3,5'-diethyl-2,6-diaminobenzene, 4-4'-methylene-bis- (3-chloro-2,6-diethylaniline) 4,4'-methylene-bis- (2,3-dichloroaniline), trimethylene glycol di-para-aminobenzoate, 4,4'-methylene-bis- (ortho Chloroaniline), 4,4'-methylene-bis- (3-chloro-2,6-diethylaniline), 4,4'-methylene-bis- (2,6-diisopropylaniline), 4,4'-methylene -Bis- (2-methyl-6-isopropylaniline), 4,4'-diaminodiphenylsulfone and the like can be used.
[0036]
In addition to the above components, additives such as a plasticizer, a pigment, an antifoaming agent, a filler, a catalyst, and a stabilizer can be blended. As the plasticizer, dioctyl phthalate (DOP), dibutyl phthalate (DBP), dioctyl adipate (DOA), tricresyl phosphate (TCP), chlorinated paraffin, dialkyl phthalate and the like can be generally used.
[0037]
As the catalyst, an organic carboxylic acid compound that is an acid catalyst is used. Specifically, aliphatic carboxylic acids such as azelaic acid, oleic acid, sebacic acid, and adipic acid, and aromatic carboxylic acids such as benzoic acid and toluic acid. Is used. In addition, triethylamine, N, N′-dimethylcyclohexylamine, amine compounds typified by triethylenediamine, stannous octoate, dibutyltin dilaurate, and organometallic compounds typified by dioctyltin marker peptide are appropriately used.
[0038]
Next, the preparation process of the urethane raw material will be described.
A liquid A in which an antifoaming agent, a plasticizer and the like are blended with the urethane prepolymer previously reacted with the isocyanate and the polyol as necessary is prepared and stored at 50 to 85 ° C. Moreover, the B liquid which melt | dissolved the hardening | curing agent completely under the atmospheric temperature of 120 degreeC or more is prepared. In addition, when mix | blending a catalyst with a urethane raw material, it is preferable to stir and mix with B liquid previously.
[0039]
The belt forming method is the same as the known manufacturing method, in a state where the core wire is spirally wound around the mold, the liquid A and the liquid B are stirred and mixed, injected into the mold, and heated under certain conditions. A belt sleeve can be produced by crosslinking and then cut into a predetermined width to produce a belt.
[0040]
In the present invention, the belt body is particularly effective when the material of the belt body is polyurethane. However, other rubber materials may be used. For example, H-NBR, CR, CSM, NBR, ethylene propylene diene monomer (EPDM), ethylene propylene copolymer (EPR), SBR, isopropylene rubber (IR), natural rubber (NR), fluoro rubber, silicon rubber, etc. Either case can be used.
[0041]
【Example】
Next, the present invention will be specifically described with reference to examples.
(Example 1)
As a core, about 200 melt-spun alkali-free glass filaments are used as strands, and the two strands are aligned, and a blocked isocyanate aqueous dispersion (block dissociation temperature 180 ° C.), RFL solution, water-insoluble epoxy The resin water dispersion was immersed in a treatment liquid (solid content 27%) mixed so that the solid content ratio was 85.7: 9.5: 4.8, and the amount of adhesion was adjusted with a die. Further, this was dried in an oven and subjected to heat treatment, and then the strand was subjected to a false twist of 2.0 times / inch, and then a twist of 1.7 times / inch was further applied to form a twisted cord. The core wire diameter at this time was 0.24 mm. As shown in FIG. 2, a core wire having a weight of 500 g attached to a support rod was installed as shown in FIG. 2, and the time required for the weight to rotate 10 times and the untwisting rotation speed were measured. The results are entered in Table 1.
[0042]
(Example 2)
Similarly, as Example 2, about 200 glass filaments same as those in Example 1 were used as strands, and the three strands were aligned to form a blocked isocyanate aqueous dispersion (block dissociation temperature 180 ° C.), RFL solution, non- The water-soluble epoxy resin aqueous dispersion was immersed in a treatment liquid (solid content 27%) mixed so that the solid content ratio was 85.7: 9.5: 4.8, and the amount of adhesion was adjusted with a die. This was dried in an oven and subjected to heat treatment, and then the strand was subjected to a false twist of 2.0 times / inch, and then a twist of 1.7 times / inch was further applied to form a twisted cord. The core wire diameter at this time was 0.30 mm. As shown in FIG. 2, a core wire having a weight of 500 g attached to a support rod was installed as shown in FIG. 2, and the time required for the weight to rotate 10 times and the untwisting rotation speed were measured. The results are entered in Table 1.
[0043]
(Example 3)
Similarly, as Example 3, about 200 glass filaments as in Example 1 were used as strands, and the same treatment as in Example 1 was performed. The strand was subjected to a twist of 2.0 times / inch to form a twisted cord. The core wire diameter at this time was 0.30 mm. Furthermore, the time required for the weight to rotate 10 times and the untwisting rotation speed were measured in the same manner as in Examples 1 and 2. The results are entered in Table 1.
[0044]
(Comparative example)
As a comparative example, about 200 glass filaments as in the example were used as strands, and the same treatment as in the example was performed. Then, a 5.7 times / inch twist was applied to the strand to form a twisted cord. The core wire diameter at this time was 0.30 mm. Furthermore, the time required for the weight to rotate 10 times and the untwisting rotation speed were measured in the same manner as in the example. The results are entered in Table 1.
[0045]
[Table 1]

[0046]
Next, a toothed belt having a belt width of 3.0 mm, a belt tooth shape ST tooth shape, a number of teeth of 723, a tooth pitch of 1.0 mm, and a belt length of 723 mm was manufactured using the core wire. As a manufacturing method, the core wire is spun into a spiral shape at a predetermined pitch in an inner mold having a groove corresponding to the tooth shape, and after setting the outer mold, 100 mass of urethane prepolymer adiprene L-100 is added. Part, 12 parts by mass of amine-based curing agent (MOCA), 40 parts by mass of plasticizer (DOP), and 0.8 parts by mass of catalyst (azelaic acid) are injected into the cavity, heat cured, and teeth An attached belt was produced.
[0047]
The appearance of the obtained toothed belt was inspected, and the torsional defect rate was calculated. As a measure of twisting failure at that time, twisting failure was determined when the belt was inclined by 45 degrees or more from the horizontal when tension was applied. The results are shown in Table 2.
[0048]
[Table 2]

[0049]
From Tables 1 and 2, it can be seen that the example requires a longer time for the weight to rotate 10 times, the twisting rotation speed is smaller, and the twisting failure rate is smaller than that of the comparative example.
[0050]
Next, for the belt having the same specifications as in Example 2, the belt width was varied to change the number of core wires contained in the belt, and the presence or absence of belt twist was observed in a stationary state. Example 4 has one core wire, Example 5 has two core wires, Example 6 has three core wires, Example 7 has four core wires, and Example 8 has core wires. The number was five. The results are shown in Table 3.
[0051]
[Table 3]

[0052]
From the results of Table 3, it can be seen that the belt in which an even number of cords are embedded in the belt does not twist at all.
[0053]
Next, a belt was used in which the number of cores in the belt was calculated to the first decimal place with the number of theoretical cores. As Example 9, the number of theoretical cords in the belt was 4.4, and as Example 10, the number of theoretical cords in the belt was 4.1. And the belt was rotated with the test machine as shown in FIG. 3, and the displacement of the thickness direction was measured using the digital displacement meter. Then, as shown in FIG. 4, the maximum tilt angle in the belt was calculated from the measured maximum value and minimum value. The running conditions at this time were an axial load of 9.8 N and a rotation speed of 500 rps. The result is shown in FIG. FIG. 5 is a graph showing the relationship between the tilt angle and the frequency of 120 belts. The greater the tilt angle, the greater the belt twist.
[0054]
From the results of FIG. 5, it can be seen that Example 10 has a higher frequency in the range where the tilt angle is smaller than that of Example 9, and the belt twist does not occur as the number of core wires in the belt approaches an even number.
[0055]
【The invention's effect】
As described above, in the present invention, the two types of glass core wires are single-twisted, two glass strands composed of glass filaments are twisted together, and the number of twists of the glass strand is 2.5 to 4.0 times. Since it is made into / inch, it has the effect of being excellent in bending fatigue resistance, having a small twisting-back force of the glass core wire, and reducing twisting failure in the belt state.
[0056]
Further, in the invention according to claim 2, the two types of glass core wires are single-twisted, and three glass strands constituted by glass filaments are twisted together, and the number of twists of the glass strand is 2.5 to 3.7. Since it is a toothed belt characterized in that it is one turn / inch, it has excellent bending fatigue resistance, the twisting back force of the glass core wire is small, and the twisting failure in the belt state can be reduced. There is an effect.
[0057]
According to the third aspect of the present invention, since the number of core wires in the belt is an even number, the toothed belt according to the first or second aspect has an effect that there is no twist in the belt state.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional view showing an example of an embodiment of a toothed belt.
FIG. 2 is a schematic view showing a method of measuring the twisting-back rotational speed and the like of the core wire.
FIG. 3 is a schematic view showing a test apparatus for measuring a tilt angle of a belt.
FIG. 4 is a conceptual diagram showing a belt tilt angle.
FIG. 5 is a graph showing the relationship between the belt tilt angle and the power.
[Explanation of symbols]
1 Toothed belt 2 Back rubber part 3 Tooth rubber part 4 Core wire 5 Support rod 7 Weight

Claims (3)

A belt body in which a plurality of tooth rubber portions are arranged at predetermined pitch intervals in the belt length direction on the belt inner surface side of the back rubber portion having a rectangular cross section extending in the belt length direction, and each of the back rubbers Two types of glass cores made of glass fiber, which are embedded in the belt length direction and embedded in parallel and alternately with a predetermined pitch interval in the belt width direction, and are twisted in different directions; In the toothed belt provided with the above, the two types of glass core wires are twisted together, and two glass strands composed of glass filaments are twisted together, and the number of twists of the glass strand is 2.5 to 4.0 times / Toothed belt characterized by being in inches. A belt body in which a plurality of tooth rubber portions are arranged at predetermined pitch intervals in the belt length direction on the belt inner surface side of the back rubber portion having a rectangular cross section extending in the belt length direction, and each of the back rubbers Two types of glass cores made of glass fiber, which are embedded in the belt length direction and embedded in parallel and alternately at predetermined pitch intervals in the belt width direction and twisted in different directions The two types of glass core wires are single-twisted and three glass strands composed of glass filaments are twisted together, and the number of twists of the glass strand is 2.5 to 3.7 times. Toothed belt, characterized in that it is one inch. The toothed belt according to claim 1 or 2, wherein the number of core wires in the belt is an even number.

Images