JP2005009658A - Toothed belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toothed belt made out of rubber such as polyurethane, and capable of reducing the failure in twisting by reducing the untwisting force of glass core wires by applying single-twist to two kinds of glass core bodies different in their twisting directions, and limiting the number of pieces of twists and the twisting number to inhibit the force to be twisted in one direction as a belt. <P>SOLUTION: In this toothed belt 1, two kinds of glass core wires 4 respectively twisted in the directions different from each other, are single-twisted, two glass strands wherein the glass core wire 4 is composed of a glass filament, are twisted together, the twisting number of the glass strand is determined to be 2.5-4.0 times/inch, and the number of pieces of core wires in the belt is determined within a range of 2n ± 0.2 pieces (n is natural number). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a toothed belt used in, for example, OA equipment.

  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. .

  The wire core has both high strength and Young's modulus and is suitable for high-load transmission. However, the disadvantage is that in the belt manufacturing process, the width is cut one by one from the cylindrical molded body, which is an assembly of many belts. When each belt is obtained, it cannot be easily cut with a blade, and if the 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.

  Polyester cores are inexpensive and have good dimensional stability against humidity and are suitable for light load transmission, but are not suitable for high load transmission due to poor strength, and have poor dimensional stability against temperature. There are disadvantages.

  The aramid core is excellent in strength as in the case of the wire core, and has the high load because 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 transmission. However, the biggest drawback is that the dimensional change with respect to humidity is large, and it is also difficult to be expensive.

  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.

Therefore, in order to meet the above requirements, a cord in which a polyester fiber yarn and a polyamide fiber yarn are twisted together (see Patent Document 1), a polybutylene terephthalate twisted cord (see Patent Document 2), a wholly aromatic polyester fiber cord Various proposals such as (see Patent Document 3) have been made, but these have not been put into practical use because they are all special products and are inferior in strength.
Japanese Utility Model Publication No. 58-35035 Japanese Utility Model Publication No.59-10540 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.

  More specifically, the glass core is a twisted yarn made of glass fiber. For the purpose of imparting excellent flexural fatigue resistance to the belt body during the twisting, the twist coefficient generally uses two types of glass cores of S twist and Z twist. By alternately arranging the belts in the belt width direction, the shifts in the belt traveling due to the twisting direction cancel each other between the glass cores.

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 4.
Special registration No. 2821369

  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.

  The problem to be solved is that in the urethane belt in which S strands and Z strands are alternately embedded, the twisting force increases, and when the number of cords is an odd number, the twisting force increases. In the case where the number of wires is an odd number, the balance of the twisting return force is lost, and a force to twist in one direction works, resulting in poor quality due to twisting failure.

  The present invention includes a belt main body in which a plurality of tooth rubber portions are disposed on a belt inner surface side of a back rubber portion having a rectangular cross section extending in the belt length direction at a predetermined pitch interval in the belt length direction, Two types of glass fiber that are embedded in the back rubber portion in the belt length direction and are arranged in parallel and alternately with a predetermined pitch interval in the belt width direction and twisted in different directions. In a toothed belt provided with a glass core, the above two types of glass core wires are single twisted, and the number of twists of the glass strand constituted by the glass filament is 2.5 to 4.0 times / inch. The most important feature is to be.

  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 single-twisted, and three glass strands composed of glass filaments are twisted together, and the number of twists of the glass strands Is a toothed belt having a speed of 2.5 to 3.7 times / inch.

  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 falls within a range of 2n ± 0.2 (n is a natural number).

  The toothed belt of the present invention is a toothed belt in which two types of glass cores are single twisted, and the number of twists of a glass strand constituted by glass filaments is 2.5 to 4.0 times / inch. Further, it has excellent bending fatigue resistance, has a small twisting return force of the glass core wire, and has an effect of reducing the twisting failure in the belt state.

  Further, in the invention according to claim 2, two types of glass core wires are single-twisted, and three glass strands composed of glass filaments are twisted, and the number of twists of the glass strand is 2.5 to 3.7 times. Since it is a toothed belt having an inch / inch, it is excellent in bending fatigue resistance, has a small twisting-back force of the glass core wire, and can reduce twisting failure in the belt state.

  According to the invention described in claim 3, the number of core wires in the belt is in the range of 2n ± 0.2 (n is a natural number). In this state, there is an effect that the twist is completely eliminated.

Hereinafter, the best mode for carrying out the present invention will be described.
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 of the tooth rubber parts 3 has an arc shape in cross section, and smoothly meshes with the tooth part of the toothed pulley around which the toothed belt is wound, so that the belt running noise is reduced.

  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 4s, the twist is applied in the S direction, and in the case of the other glass core 4z, it is Z-twisted to form a single twist.

  And the twist coefficient 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 2.5-4.0 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 degradation during belt running becomes remarkable. Further, when the three strands of the S-strand and Z-strand glass cores 4s and 4z are twisted, the number of twists of the glass strand is set to 2.5 to 3.7 times / inch. The number of core wires embedded in the belt is preferably in the range of 2n ± 0.2 (n is a natural number).

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.

  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 tridiisocyanate, butane-1,2,2-tri Illustrative examples include isocyanate, trimethylolpropane tolylene diisocyanate trimer, triisocyanate compounds such as 2,4,4'-diphenyl ether triisocyanate, and polyisocyanate compounds such as polymethylene polyphenyl isocyanate.

  As the blocking agent for blocking the isocyanate, lactams and oximes are preferably used. Specific examples of oximes include acetooxime, methyl ethyl ketone oxime, cyclohexanone oxime, benzophenone oxime, and the like. , Ε-caprolactam and the like. As other blocking agents, lower alcohols, phenols, active methylene compounds, imides and the like can also be used.

  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.

  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.

  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.

  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.

  Although it does not limit as isocyanate, Aromatic polyisocyanate, aliphatic polyisocyanate, alicyclic polyisocyanate, and those modified substances can be used. Specific examples include toluene diisocyanate (TDI), methylene diisocyanate (MDI), xylene diisocyanate (XDI), naphthalene diisocyanate (NDI), hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPDI). MDI is preferably used.

  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, poly-ε-caprolactone (PCL) and the like.

  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- (2N-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'diaminodiphenyl sulfone, etc. can be used.

  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), dioctyl adipate (DOA), tricresyl phosphate (TCP), chlorinated paraffin, dialkyl phthalate and the like can be used.

  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. An 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.

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 80 ° C. Moreover, the B liquid which melt | dissolved the hardening | curing agent completely at 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.

  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.

  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.

  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 heat-treated, and then the strand was twisted 3.7 times / inch 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.

  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.

  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 strands were twisted 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.

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.

  Next, a toothed belt having a belt width of 3.0 mm, a belt tooth profile 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, after spinning the core wire into a spiral shape at a predetermined pitch in an inner mold having a groove corresponding to the tooth shape and setting the outer mold, 100 parts by mass of urethane prepolymer adiprene L-100 A urethane compound containing 12 parts by mass of an amine curing agent (MOCA), 40 parts by mass of a plasticizer (DOP), and 0.8 parts by mass of a catalyst (azelaic acid) is injected into the cavity, and cured by heating and toothed. A belt was produced.

  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.

  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.

  Next, a belt having the same specifications as the belt of Example 2 was observed by changing the belt width and changing the number of core wires included in the belt, and observing the occurrence of twisting of the belt 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.

  From the results in Table 3, it can be seen that the belt in which 2n cords (n is a natural number) are buried in the belt does not twist at all.

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 cores in the belt was 4.4, and as Example 10, the number of theoretical cores 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 of the 120 belts and the power. The greater the tilt angle, the greater the belt twist.

From the results shown in FIG. 5, the tenth embodiment has a higher frequency in the range where the tilt angle is smaller than that in the ninth embodiment, and the belt is within the range of 2n ± 0.2 cores (n is a natural number). It can be seen that no twisting occurs.

It is a partial sectional view showing an example of an embodiment of a toothed belt. It is the schematic which shows the method of measuring the twisting-back rotation speed etc. of a core wire. It is the schematic which showed the test device for measuring the inclination angle of a belt. It is the schematic which showed the fall angle of the belt. It is the graph which showed the relationship between the fall angle of a belt, and frequency.

Explanation of symbols

DESCRIPTION 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 above-mentioned two types of glass core wires are single twisted, and the number of twists of the glass strand constituted by the glass filament is 2.5 to 4.0 times / inch. Toothed belt.   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 falls within a range of 2n ± 0.2 (n is a natural number).

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