JP2005024075A - Toothed belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toothed belt which enhances responsiveness by making elongation of a core wire small as well overshooting on follower side when being started or stopped and enhances transmission capacity by reducing jumping and improves durability in travelling under high temperature and high tensile force and under high temperature and high humidity. <P>SOLUTION: The device is the toothed belt 1 which includes a plurality of cogs 2 disposed along lengthwise direction at predefined distance and a back portion 4 imbedding the core wire 3, and which covers toothed cloth 5 on surface of the cogs 2. The core wire 3 is a cord which coats adhered layer on the surface and thus is wire adhering the adhered layer on the surface by half-twisting it at 5-10 times/10cm after it adheres to impregnate treated fluid comprising rubber latex and epoxy resins on multi filament yarn made of carbon fiber of which the total number of denier amounts to 1,000-10,000. Furthermore, it is configured so that rate of cross sectional area in fiber occupying on cross sectional area in the cord amounts to 70-90% and tensile elastic modulus of the belt amounts to 50-85N/mm<SP>2</SP>. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a toothed belt, which is used for a robot arm or a driving device of an automobile. The elongation of the core wire is reduced, the overshoot on the driven side at the time of starting or stopping is reduced, and the responsiveness is improved. The present invention relates to a toothed belt that has reduced jumping, increased transmission capacity, and improved durability in running under high temperature and high tension and high temperature and high humidity.

  The toothed belt is composed of a plurality of tooth portions provided along the longitudinal direction on the inner surface side thereof, and a back portion in which a core wire is embedded, and is provided on the surface of the tooth portion and the surface of the tooth bottom portion between adjacent tooth portions. A reinforcing member is attached along the surface. As the reinforcing member, a weft parallel to the longitudinal direction of the toothed belt and a woven fabric woven so as to intersect with the weft are used.

  Here, the problems regarding the durability of the toothed belt are roughly classified into belt cutting due to fatigue of the core wire and tooth chipping due to overload and wear of the reinforcing member. For belt cutting due to fatigue of the core wire, use of an aramid core wire or a thin core wire of high-strength glass, use of a rubber compound with excellent heat resistance, and constant belt tension at both starting and running Improvements have been made, such as through the use of auto-tensioners that maintain.

  In addition, a transmission belt using carbon fiber instead of glass fiber or aramid fiber as the core wire has been proposed. For example, Patent Document 1 uses a carbon fiber cord as a core wire for a urethane elastomer belt material, and Patent Document 2 discloses a belt body before twisting a thermoplastic elastomer belt material with a single twisted carbon fiber cord. The one that has been treated with a thermoplastic elastomer of the same material as the one used to improve adhesion is used. Patent Document 2 discloses that the upper twist coefficient is 2.0 to 4.0, the lower twist coefficient is 1/2 to 3/2 of the upper twist coefficient, the initial strength is large, the elongation is small, and the water resistance is high. A toothed belt with improved durability and bending fatigue resistance is disclosed.

However, in a conventional robot arm drive device in which a toothed belt is suspended on a drive shaft and a driven shaft, high responsiveness is required, and it is required to reduce the overshoot on the driven side at the time of start and stop. Yes. That is, since the toothed belt suspended on the drive shaft and the driven shaft is slightly extended, the response is deteriorated due to the stop by the overshoot on the driven side when the drive side is stopped. For this reason, a belt having a smaller elongation than the conventional toothed belt is required, and development of the material and configuration of the core wire has been desired.
Further, in the case of a conventional toothed belt, in the case of high load transmission, the belt jumping occurs due to the elongation of the core wire, and the remaining belt strength after running may be greatly reduced compared to before running.
Patent No. 2945554 Japanese Patent Laid-Open No. 10-2379 Japanese Patent Publication No. 03-4782

  The problem to be solved is to reduce the extension of the core wire, to reduce the overshoot on the driven side at the time of starting or stopping, to improve the response, to reduce the jumping and to increase the transmission capacity, and to An object of the present invention is to provide a toothed belt having improved durability in running under tension and high temperature and high humidity.

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 portion in which a core wire is embedded, and a toothed surface in which a tooth cloth is coated on the surface of the tooth portion. In the belt,
The core wire is impregnated with a treatment liquid composed of a rubber latex and an epoxy resin on a multifilament yarn of carbon fiber having a total denier of 1,000 to 10,000, and is then twisted 5-10 times / 10 cm. A toothed belt having a cord coated with an adhesive layer on the surface, a ratio of a fiber cross-sectional area to a cord cross-sectional area of 70 to 90%, and a tensile elastic modulus of the belt of 50 to 85 N / mm ² It is in.

The invention according to claim 2 of the present application has a plurality of tooth portions arranged at predetermined intervals along the length direction, and a back portion in which a core wire is embedded, and the tooth portion is coated with a tooth cloth on the surface of the tooth portion. In the belt,
The core wire is impregnated with a treatment liquid composed of rubber latex and epoxy resin on a multifilament yarn of carbon fiber having a total denier of 1,000 to 10,000, and then twisted at 5-10 times / 10 cm. The cord is further twisted 2.5 to 5 times / 10 cm and coated with an adhesive layer on its surface, and the ratio of the fiber cross-sectional area to the cord cross-sectional area is 70 to 90%. The toothed belt has a tensile elastic modulus of 50 to 85 N / mm ² .

  The invention according to claim 3 of the present application resides in a toothed belt in which the adhesive layer is a single layer obtained from a resorcin-formaldehyde-latex solution.

  The invention of claim 4 of the present application resides in a toothed belt in which the adhesive layer is a single layer obtained from rubber paste.

  The invention of claim 5 is a toothed belt in which the adhesive layer is composed of two layers, a lower layer made of resorcinol-formaldehyde-latex liquid and an upper layer made of rubber paste.

In the toothed belt of the present invention, the carbon fiber multifilament yarn is impregnated with a treatment liquid composed of a rubber latex and an epoxy resin, so that the friction between the filaments is reduced and mechanical damage is also reduced. In addition, by forming a twisted cord with a specific twist, the strength is maintained, the elongation is reduced, the modulus is improved, and the bending fatigue property is also improved. In addition, the adhesion strength with the back portion is improved by attaching the adhesive layer, and the ratio of the fiber cross-sectional area to the cord cross-sectional area is set to 70 to 90% and a large amount of carbon fiber is filled. Is set to 50 to 85 N / mm ² , thereby reducing the elongation of the core wire, reducing the overshoot on the driven side when starting or stopping, and improving the responsiveness, Further, the jumping can be reduced to increase the transmission capacity, and the durability in running under high temperature and high tension and high temperature and high humidity can be improved.

  FIG. 1 is a partial front view of a toothed belt according to the present embodiment, in which a toothed belt 1 includes a plurality of tooth portions 2 arranged at predetermined intervals along the longitudinal direction, a back portion 4 continuous with the tooth portions 2, It has a core wire 3 embedded in the back part 4 and a tooth cloth 5 coated on the surface of the tooth part 2. The tooth cloth 5 is composed of a fiber material formed by weaving wefts extending in the longitudinal direction of the belt and warps extending in the width direction of the belt as a base material.

  The core wire 3 is obtained by impregnating a multifilament yarn of carbon fibers having a total denier of 1,000 to 10,000 with a treatment liquid composed of a rubber latex and an epoxy resin, and then twisting it at 5 to 10 times / 10 cm. Alternatively, various twisted cords may be twisted at 5-10 times / 10 cm and further twisted at 2.5-5 times / 10 cm.

The monofilament (single fiber) constituting the multifilament yarn of carbon fiber has a cross-sectional shape that is substantially close to a perfect circle, efficiently gathering many filaments, and reducing the space between closely spaced filaments The strength of the cord is increased. Specifically, the ratio of the fiber cross-sectional area to the cord cross-sectional area is 70 to 90%, the filament group is efficiently and highly filled, and the tensile elastic modulus of the belt is 50 to 85 N / mm ² . If it is oval, the cords are more likely to break than the monofilaments rub against each other. If the shape is other than this, even if the filaments are gathered, the space between the closely spaced filaments increases and the strength of the cord cannot be improved.

  The content of the treatment liquid (solid content) in the cord is 10 to 40 parts by mass, preferably 15 to 35 parts by mass with respect to 100 parts by mass of the carbon fiber multifilament yarn. If the amount is less than 10 parts by mass, the fatigue resistance of the cord may be reduced due to friction between monofilaments, while if it exceeds 40 parts by mass, the heat resistance, water resistance, and solvent resistance of the cord may be reduced. .

  Content of the rubber latex (solid content) contained in the said processing liquid (solid content) is 20-80 mass parts with respect to 100 mass parts of processing liquid (solid content), Preferably it is 30-70 mass parts. If the amount is less than 20 parts by mass, the flexibility of the cord may be reduced and the bending fatigue resistance of the belt may be reduced. On the other hand, if the amount exceeds 80 parts by mass, the cord becomes too sticky and the handling property becomes poor. .

  Specific examples of the rubber latex include acrylonitrile-butadiene rubber latex, chloroprene rubber latex, styrene-butadiene rubber latex, hydrogenated nitrile rubber latex (H-NBR latex), styrene-butadiene-vinylpyridine terpolymer (VP). Latex), and one or more blends of EPDM rubber latex are used.

  Content of the epoxy resin in the processing liquid contained in the said processing liquid (solid content) is 20-80 mass parts with respect to 100 mass parts of processing liquid (solid content), Preferably it is 30-70 mass parts. If the amount is less than 20 parts by mass, the adhesion between the cord and the rubber interface may be lowered. If the amount exceeds 80 parts by mass, the flexibility of the cord may be lowered and the bending fatigue resistance of the belt may be lowered.

  Specific examples of the epoxy resin include one or more of ethylene glycol diglycidyl ether, glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, sorbitol polyglycidyl ether, hexanediol diglycidyl ether, and the like.

  An adhesive layer is attached to the surface of the above cord. Here, the adhesive layer may be a single layer obtained from resorcin-formaldehyde-latex liquid (RFL liquid), or obtained from rubber paste. One layer may be sufficient, and also two layers of the lower layer which consists of RFL liquid, and the upper layer which consists of rubber paste may be sufficient.

  The RFL liquid is a mixture of resorcin and formaldehyde initial condensate and rubber latex. In this case, the molar ratio of resorcin and formaldehyde is preferably 3/1 to 1/3 in order to increase the adhesive force. is there. The initial condensate of resorcin and formaldehyde is mixed with rubber latex so that the resin content is 5 to 50 parts by mass with respect to 100 parts by mass of rubber latex, and further resorcin and formaldehyde containing phenol resin The mass ratio of the solid content of the initial condensate and rubber latex is adjusted to 5/95 to 40/60. If it is less than 5/95, the adhesiveness is remarkably lowered, and if it exceeds 40/60, the rubber latex content is reduced, the heat resistance is deteriorated, and the bending fatigue property is lowered.

  Examples of rubber latex used in the RFL treatment liquid include hydrogenated nitrile rubber latex (H-NBR latex), styrene-butadiene-vinylpyridine terpolymer (VP latex), chloroprene rubber latex, and EPDM rubber latex. A blend of seeds or more is used. Hydrogenated nitrile rubber latex and vinylpyridine rubber latex are mixed at a mass ratio of solid content of 60/40 to 95/5. When the mass ratio of the hydrogenated nitrile rubber is less than 60, the heat resistance is deteriorated and the bending fatigue property is lowered. When the mass ratio is more than 95, the water resistance is significantly lowered.

  The carbon fiber cord used is processed by the following method. First, the untreated untwisted multifilament yarn is impregnated with a treatment liquid composed of rubber latex and epoxy resin, and then heat-treated through an oven adjusted to 130 to 250 ° C. Subsequently, various twisted cords obtained by twisting the treated multifilament yarn at 5-10 times / 10 cm, or by twisting at 5-10 times / 10 cm and further twisting at 2.5-5 times / 10 cm. After that, this cord is impregnated with an RFL solution to form an adhesive layer.

Further, the treatment cord is dipped in rubber paste to adhere a rubber layer, and then heat-treated through an oven adjusted to around 130 to 180 ° C.
In addition to hydrogenated nitrile rubber (H-NBR), chloroprene rubber (CR), and chlorosulfonated polyethylene rubber (CSM), NBR, ethylene propylene diene monomer (EPDM), ethylene propylene copolymer (EPR) ), SBR, rubber blends of isoprene rubber (IR), natural rubber (NR), and those obtained by dissolving in solvents such as aromatic hydrocarbons such as toluene and xylene.

  Further, the treatment cord may be impregnated in the RFL solution in the same manner as described above to form a lower layer and then overcoated with rubber glue to form two upper layers.

  In addition to hydrogenated nitrile rubber (H-NBR), chloroprene rubber (CR), and chlorosulfonated polyethylene rubber (CSM), NBR, ethylene propylene diene can be used as the raw rubber for the rubber compound forming the tooth 2 and the back 4 Monomer (EPDM), ethylene propylene copolymer (EPR), SBR, isoprene rubber (IR), natural rubber (NR), fluorine rubber, etc. can be used, but preferably hydrogenated nitrile rubber (H- NBR), chloroprene rubber (CR), and chlorosulfonated polyethylene rubber (CSM). The raw rubber is blended with a filler, a reinforcing agent such as carbon black, a vulcanizing aid, a vulcanizing agent, and the like.

  The rubber hardness of the tooth portion 2 is at least 67 degrees or more, preferably 73 degrees or more (JISA) for high load transmission. As the rubber compound, a hydrogenated nitrile rubber having a hydrogenation rate of at least 90%, preferably 92 to 98% is used from the viewpoint of heat resistance, or an unsaturated carboxylic acid metal salt is added to the hydrogenated nitrile rubber as a total polymer. What added 20-60 mass parts with respect to is preferable. Thereby, a modulus (tensile modulus), a cutting elongation, and a higher tear strength and hardness can be ensured.

  Furthermore, in order to improve heat resistance, it is desirable to use hydrogenated nitrile rubber or hydrogenated nitrile rubber added with an unsaturated carboxylic acid metal salt as a main component and a peroxide vulcanization system.

  Examples of the organic peroxide include dicumyl peroxide, di-t-butyl peroxide, t-butylcumyl peroxide, benzoyl peroxide, 1,3-bis (t-butylperoxyisopropyl) benzene, 2, 5-dimethyl-2,5-di (t-butylperoxy) hexyne-3, 2,5-dimethyl-2,5- (benzoylperoxy) hexane, 2,5-dimethyl-2,5-mono (t -Butylperoxy) hexane etc. can be mentioned. This organic peroxide is usually used alone or as a mixture in the range of 0.005 to 0.02 mol g per 100 g of the raw rubber.

  As materials of the weft and the warp constituting the tooth cloth 4, any one or combination of polyamide, aramid, polyester, and polybenzoxazole fibers can be adopted. The form of the fiber may be either a filament yarn or a spun yarn, and may be any one of a single composition twisted yarn, a mixed twisted yarn, or a blended yarn. A yarn in which spun yarns or filaments are gathered to such an extent that the RFL solution can be impregnated into the inside of the fiber is preferable. Further, since the aramid fiber or the polybenzoxazole fiber itself is a fiber having a low coefficient of friction, the chipping resistance is improved by including at least the weft in the longitudinal direction of the belt. Further, the weaving configuration may be a twill weave, satin weave, plain weave, or the like.

Next, the present invention will be specifically described with reference to examples.
Examples 1-3
A carbon fiber untwisted multifilament yarn (T700GC / 6K / 31E (model number, manufactured by Toray Industries, Inc.) fineness 4,300 denier) is treated with a treatment liquid (vinylpyridine-styrene-butadiene rubber latex having a fixed concentration of 40% by mass). : An oven whose temperature was adjusted to 140 ° C. after impregnation by passing it through a treatment bath containing 200 parts by mass of JSR and 200 parts by mass of ethylene glycol diglycidyl ether in 500 parts by mass of water) Heat-treat through. Subsequently, the treated multifilament yarn was twisted at 5 times / 10 cm to form a cord, and then the cord was immersed in the RFL solution shown in Table 1 and heat treated in the range of 130 to 180 ° C. to form an adhesive layer. Formed.

  The result of having measured the relationship between the number of single twists of the said process cord and the strength with an autograph is shown in FIG. According to this, it can be seen that a high strength can be maintained if the number of twists is 5 to 10 times / 10 cm in a single twisted cord.

  As a rubber sheet for the tooth portion and the back portion, a rubber composed of H-NBR shown in Table 2 was kneaded by a usual method and adjusted to a predetermined thickness by a calendar roll.

  As the tooth cloth, 6,6 nylon was used as the warp, and a twill weave was used using a mixed yarn of 6,6 nylon and urethane elastic yarn as the weft.

  Next, the tooth cloth is wound around a die having 120 teeth of STPD tooth profile for belt production, and a pair of SZ twisted carbon fiber cords (number of single twists, 5 times / 10 cm) as a core wire is pitched (1.0 mm / This was wound around the spiral with a predetermined tension. A rubber sheet shown in Table 3 was wound on the core wire, and a jacket was put on and put into a vulcanizing can, and pressure vulcanized by a normal press-fitting method to form a tooth profile. Thereafter, the back surface of the belt was ground to a certain thickness and cut to a certain width (10.0 mm) to obtain a running toothed belt.

  There are three types of belts, belt width 10.0 mm, belt tooth profile STPD, number of teeth 120, tooth pitch 5.00 mm, type 1, belt width 19.0 mm, belt tooth profile STPD, number of teeth 105 teeth, tooth pitch 8. The type 2 was 00mm, and the belt width was 30.0mm, the belt tooth profile STPD, the number of teeth was 100 teeth, and the tooth pitch was 14.00mm.

Comparative Example 1
As a core wire, three untwisted glass fibers (E-glass) were aligned and immersed in an RFL treatment solution shown in Table 2, and then heat treated at 200 to 280 ° C. A single twisted cord was prepared in the S and Z directions at a twist number of 8 times / cm. 11 of these were aligned and twisted at 12 times / cm. Furthermore, this was immersed in rubber paste and heat-treated in the range of 130 to 180 ° C. Thereafter, three types of toothed belts were produced using the same tooth portion and back rubber sheet and tooth cloth as in Example 1 and under the same production conditions.

  There are three types of belts, belt width 10.0 mm, belt tooth profile STPD, number of teeth 120, tooth pitch 5.00 mm, type 1, belt width 19.0 mm, belt tooth profile STPD, number of teeth 105 teeth, tooth pitch 8. The type 2 was 00mm, and the belt width was 30.0mm, the belt tooth profile STPD, the number of teeth was 100 teeth, and the tooth pitch was 14.00mm.

  Table 3 shows the results of calculating the cord diameter, the cord cross-sectional area, the fiber cross-sectional area occupation ratio, and the belt elastic modulus (per width) of the toothed belts according to the above-described Examples and Comparative Examples. The belt elastic modulus was measured by an autograph at room temperature for the relationship between the belt axial distance change rate and the axial load.

  According to this, it can be seen that the embodiment has a smaller elongation due to higher strength and higher elastic modulus than the comparative example, and the dimensional change at the time of high belt tension is smaller. Moreover, about the fiber cross-sectional area occupation rate in a code | cord | chord cross-sectional area, it turns out that the filling amount of the fiber of the carbon fiber cord of an Example is large compared with the glass fiber cord of a comparative example.

Subsequently, as an evaluation of the toothed belt manufactured in the example and the comparative example, a responsiveness evaluation was performed as an evaluation of positioning accuracy such as driving of the robot arm. As this running test apparatus, the toothed belt is suspended at a tension of 10 kgf on a 35-tooth driven pulley connected with a driving motor, a 35-tooth driven pulley to which a flywheel (GD ² = 0.402 kgm ² ) is attached. Applying a torque of 80.4 g · m, rotating the drive pulley and the driven pulley as a test pattern, rotating forward and reverse at a rotation speed of 90 degrees / second, acceleration / deceleration speed of 450 degrees / second ² and a pulley rotation angle of 360 degrees 20 times each. Differences were detected by the rotary encoder during start / stop. The result is shown in FIG.

  In addition, a jumping test was performed to compare the transmission capacity of the toothed belt. In this jumping test, the load on the driven shaft was increased while the belt was running, and the load value when jumping (tooth skipping) occurred was measured. As test conditions, a toothed belt was suspended on a 22-tooth driven pulley and a 20-tooth driven pulley, and measurement was performed at a rotational speed of 3,600 rpm and an axial load of 10.6 kgf. The results are also shown in Table 4.

  According to this, the toothed belt of the example has a high responsiveness with a small rotational difference between the driving pulley and the driven pulley at the time of start / stop in the responsiveness evaluation, and further, the jumping test hardly causes the transmission capacity. It turns out to be expensive.

The toothed belt of the present invention is used for a drive device for moving a driven robot arm by rotation on the drive side or a drive device for an overhead camshaft of an automobile. When the area ratio is 70 to 90% and a large amount of carbon fiber is filled, the tensile elastic modulus of the belt is set to 50 to 85 N / mm ² , thereby reducing the elongation of the core wire, and starting or stopping The overshoot on the driven side can be reduced, the responsiveness can be improved, and the transmission capacity is also increased.

It is a partial front view of the toothed belt which concerns on this embodiment. It is a graph which shows the number of single twists of the said process cord, and a strong relationship. The result of having detected the overshoot at the time of starting / stopping with the rotary encoder about the rotation difference of the driving pulley and the driven pulley in Example 1 is shown. The result of having detected the overshoot at the time of starting / stopping with the rotary encoder about the rotation difference of the driving pulley and the driven pulley in comparative example 1 is shown.

Explanation of symbols

1 Toothed belt 2 Tooth part 3 Core wire 4 Back part 5 Tooth cloth

Claims (5)

In a toothed belt having a plurality of tooth portions arranged at predetermined intervals along the length direction and a back portion in which a core wire is embedded, and having a tooth cloth coated on the surface of the tooth portion,
The core wire is impregnated with a treatment liquid composed of a rubber latex and an epoxy resin on a multifilament yarn of carbon fiber having a total denier of 1,000 to 10,000, and is then twisted 5-10 times / 10 cm. The cord has a surface coated with an adhesive layer, the ratio of the fiber cross-sectional area to the cord cross-sectional area is 70 to 90%, and the tensile elastic modulus of the belt is 50 to 85 N / mm ^2. Toothed belt. In a toothed belt having a plurality of tooth portions arranged at predetermined intervals along the length direction and a back portion in which a core wire is embedded, and having a tooth cloth coated on the surface of the tooth portion,
The core wire is impregnated with a treatment liquid composed of rubber latex and epoxy resin on a multifilament yarn of carbon fiber having a total denier of 1,000 to 10,000, and then twisted at 5-10 times / 10 cm. The cord is further twisted 2.5 to 5 times / 10 cm and coated with an adhesive layer on its surface, and the ratio of the fiber cross-sectional area to the cord cross-sectional area is 70 to 90%. A toothed belt having a tensile elastic modulus of 50 to 85 N / mm ² . The toothed belt according to claim 1 or 2, wherein the adhesive layer is a single layer obtained from a resorcin-formaldehyde-latex solution. The toothed belt according to claim 1 or 2, wherein the adhesive layer is a single layer obtained from rubber paste. The toothed belt according to claim 1 or 2, wherein the adhesive layer comprises two layers, a lower layer made of resorcin-formaldehyde-latex liquid and an upper layer made of rubber paste.

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