Toothed belt

Abstract

To provide a toothed belt having favorable positioning performance and responsiveness.SOLUTION: A toothed belt comprises a belt main body having multiple tooth parts which are arranged at a belt internal periphery at constant pitches, and a core wire along a belt length direction, embedded into the belt main body so as to form a spiral shape having a pitch in the belt length direction. The core wire includes carbon fibers having filament diameters of 4 to 6 μm as a constituent, and is formed of twisted yarns of 5,000 to 7,000 pieces of filament including the carbon fibers, the number of times of single twits or the number of times of top twists of the twisted yarns is 4 to 10 times / 10 cm, a diameter of the core wire is 0.5 to 0.6 mm, and the pitch of the core wire is 0.70 to 0.85 mm.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a toothed belt. [Background technology]

[0002] Toothed belts are suitable for applications requiring synchronous rotation, and are used, for example, as belts for synchronously transmitting power between the crankshaft and cam of an automobile engine (for example, Patent Document 1). In addition, they are also used in belt transmission systems that require synchronous transmission in precision machinery such as cameras, computers, and copiers, and general industrial machinery such as robots. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2004-138239 A Summary of the Invention [Problem to be solved by the invention]

[0004] For example, toothed belts used in robots are required to have good positioning properties. In addition, in the field of robotics, there is a demand for lighter and more compact parts to reduce inertia, and therefore there is a demand for toothed belts used in robots to meet the above-mentioned demands for lighter and more compact parts. For example, when using a toothed belt to drive a robot arm, it is proposed to use a toothed belt with a tooth pitch of 5 mm in a two-axis layout with a small diameter pulley of about φ20 mm. In addition, toothed belts used in robots are also required to be capable of transmitting high loads. [Means for solving the problem]

[0005] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a toothed belt which has excellent positioning properties and can be used for high load transmission.

[0006] (1) The toothed belt of the present invention is A belt body having a plurality of teeth provided at a constant pitch on an inner circumference of the belt; a core wire embedded in the belt body so as to form a spiral having a pitch in the belt width direction along the belt length direction; Equipped with The core wire includes, as a constituent material, carbon fiber having a filament diameter of 4 to 6 μm, and is a twisted yarn of 5,000 to 7,000 filaments including the carbon fiber, The twisted yarn has a number of single twists or second twists of 4 to 10 per 10 cm, The diameter of the core wire is 0.50 to 0.60 mm, The pitch of the core wire is 0.70 to 0.85 mm.

[0007] According to the toothed belt of the present invention, the specific core wires described above are embedded in the belt body at a predetermined pitch, so that the toothed belt has excellent positioning properties. Moreover, since the core wire of the toothed belt uses a core wire containing carbon fiber, the toothed belt can be suitably used for high-load transmission applications such as driving the arms of industrial robots. In the present invention, positioning ability refers to the ability to stop a pulley rotated by a toothed belt at a commanded target position when a positioning operation is performed in which the pulley is rotated in one direction from a certain position and then stopped at a specified position, and the smaller the deviation between the target position and the actual stopping position, the better the positioning accuracy.

[0008] (2) The toothed belt preferably has a tooth pitch of 5 mm. A toothed belt having the core wire described in (1) above is particularly suitable for improving the positioning ability of a toothed belt having such a tooth pitch.

[0009] (3) The above toothed belt has a bending stiffness of 7.33 Ncm2 It is preferable that: In this case, the toothed belt can be bent with a small force when wound around the pulley, so there is no need to apply high tension to the belt and the rigidity of the device can be reduced. Furthermore, the lower the rigidity of the belt, the smaller the power transmission energy loss and the better the bending fatigue and responsiveness of the belt.

[0010] (4) The toothed belt preferably has an elastic modulus M1.0 (stress at an elongation rate of 1.0%) of 300 N / mm or more. In this case, the toothed belt has a belt strength that can suppress the belt elongation rate when a load is applied to the belt due to power transmission to about 1.0% at most. Therefore, a toothed belt having an elastic modulus in the above range when the elastic modulus M is 1.0% can suppress the belt elongation in response to a load when a load is applied, and the toothed belt has good positioning accuracy.

[0011] (5) In the toothed belt, the belt body is preferably made of a rubber composition or an elastomer composition having a hardness (JIS-A) of 84-94. In this case, the toothed belt has good responsiveness as well as good positioning ability. Effect of the Invention

[0012] According to the present invention, a toothed belt with excellent positioning properties can be provided. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a perspective view showing a toothed belt according to a first embodiment. [Diagram 2] FIG. 2 is a front view taken along an arrow X in FIG. [Diagram 3] FIG. 2 is an end view taken along line AA in FIG. [Figure 4] FIG. 2 is a partial cross-sectional view of a belt forming die used for manufacturing a toothed belt. [Diagram 5]3A to 3C are diagrams illustrating a manufacturing process of a toothed belt. [Figure 6] 3A to 3C are diagrams illustrating a manufacturing process of a toothed belt. [Figure 7] 3A to 3C are diagrams illustrating a manufacturing process of a toothed belt. [Figure 8] FIG. 2 is a diagram showing the pulley layout of a belt testing machine used in evaluating positioning ability. [Figure 9] 11 is a graph showing the relationship between the rotational torque and the amount of displacement on the pitch line of the toothed belt, obtained in an evaluation of positioning ability. [Figure 10] FIG. 2 is a diagram showing a pulley layout of a belt tester used in evaluating responsiveness. [Figure 11] 4 is a graph showing the evaluation results of the toothed belt of Example 2, and is a graph showing the time changes in the rotation speed of each of a driving pulley and a driven pulley. [Figure 12] 10 is a graph showing the evaluation results of the toothed belt of Example 2, and is a graph showing the change over time in the difference in the rotation speed between a driving pulley and a driven pulley. BEST MODE FOR CARRYING OUT THEINVENTION

[0014] Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments. Fig. 1 is a perspective view showing a part of a toothed belt 10 according to an embodiment of the present invention, Fig. 2 is a front view taken along an arrow X in Fig. 1, Fig. 3 is an end view taken along line AA in Fig. 1.

[0015] The toothed belt 10 is used, for example, to drive a robot arm. Although only a portion of the toothed belt 10 is shown in FIG. 1, the toothed belt 10 is an endless intermeshing power transmission belt. As shown in FIG. 1, the toothed belt 10 includes a belt body 11, a core wire 13, and a reinforcing cloth 14.

[0016] The toothed belt 10 is a relatively small toothed belt, with a belt circumference (belt length at the belt pitch line BL) of, for example, 200 mm to 2000 mm, a belt width of, for example, 4 mm to 30 mm, and a maximum belt thickness of, for example, 3.0 mm to 4.0 mm. Even with these dimensions, the toothed belt 10 has excellent positioning properties. A toothed belt with these dimensions is also suitable for miniaturizing and reducing the weight of, for example, a robot. Of course, the dimensions of the toothed belt according to the embodiment of the present invention are not limited to this range.

[0017] The toothed belt 10 has a plurality of belt teeth 12 arranged at intervals at a predetermined pitch on the inner circumferential side. The tooth profile of the belt teeth 12 is preferably a circular-arc tooth profile, and among circular-arc tooth profiles, an S-tooth profile is more preferable. The S-tooth profile reduces backlash between the belt teeth and the pulley groove, and has a large belt tooth width and height. In addition, the tip of the belt tooth closely meshes with the bottom of the pulley groove, so the force on the pressure surface of the tooth that the toothed belt receives is distributed and uniform, and deformation of the teeth is small, making it suitable for a design with excellent positioning accuracy.

[0018] In the embodiment of the present invention, the tooth profile of the belt teeth 12 is not limited to an S-shape, but may be a circular arc tooth profile other than an S-shape, a trapezoidal tooth profile, or another tooth profile.

[0019] In the toothed belt 10, the belt teeth 12 are straight teeth extending parallel to the belt width direction. In the embodiment of the present invention, the belt teeth 12 may be helical teeth extending in a direction inclined with respect to the belt width direction.

[0020] In the toothed belt 10, the tooth pitch P of the belt teeth 12 (see P in FIG. 3) is, for example, not less than 2 mm and not more than 8 mm. Subdividing the tooth pitch improves the positioning accuracy. The larger the tooth size, the higher the power transmission is possible. Therefore, from the viewpoint of achieving both good positioning accuracy and high power transmission performance, the tooth pitch P of the belt teeth 12 is preferably 3 mm or more and 5 mm or less, and 5 mm is particularly preferable.

[0021] The tooth height of the belt teeth 12 is defined by the dimension from the tooth bottom 15 between a pair of adjacent belt teeth 12 in the belt length direction to the tip of the belt tooth 12 (see H in FIG. 3), and is, for example, 1.7 mm to 2.2 mm. The toothed belt 10 has a number of teeth, for example, from 40 to 400, a tooth width (dimension in the belt length direction) of, for example, from 200 mm to 2000 mm, and a PLD of, for example, from 0.450 mm to 0.600 mm.

[0022] The belt body 11 is made of rubber (including elastomer) and has an endless flat band-shaped back rubber part 11a and multiple tooth rubber parts 11b. The multiple tooth rubber parts 11b are integrally provided at intervals in the belt length direction on the inner circumferential side, which is one side of the back rubber part 11a. The belt body 11 is made of a rubber composition obtained by vulcanizing an unvulcanized rubber composition, for example, a rubber component mixed with various rubber compounding agents, by heating and pressurizing the rubber component during belt molding. The constituent materials of the back rubber portion 11a and the tooth rubber portion 11b may be the same or different.

[0023] Examples of the rubber component of the rubber composition forming the belt body 11 include hydrogenated nitrile rubber (H-NBR), ethylene-α-olefin elastomer (such as EPDM or EPR), chloroprene rubber (CR), chlorosulfonated polyethylene rubber (CSM), etc. The hydrogenated nitrile rubber (H-NBR) may contain an unsaturated carboxylate metal salt in H-NBR. These rubber components may be used alone or in combination of two or more. The toothed belt 10 may be used, for example, as a toothed belt 10 for driving a robot arm in a robot used in a harsh environment unsuitable for human activity. In this case, the belt body 11 of the toothed belt 10 may be required to have heat resistance, oil resistance, and weather resistance. From this viewpoint, the rubber component preferably contains H-NBR.

[0024] When the rubber component of the rubber composition is H-NBR, the amount of bound acrylonitrile is preferably 20% by mass or more and 50% by mass or less. The iodine value is preferably 5 mg / 100 mg or more and 15 mg / 100 mg or less. The Mooney viscosity at 100° C. is preferably 40 ML or less. 1+4 (100℃) or more 90ML 1+4 (100°C) or less is preferable.

[0025] Examples of the rubber compounding agents include vulcanization accelerators, antioxidants, reinforcing materials, plasticizers, co-crosslinking agents, and crosslinking agents.

[0026] Examples of the vulcanization accelerating aid include metal oxides such as zinc oxide (zinc white) and magnesium oxide, metal carbonates, fatty acids and derivatives thereof, etc. It is preferable to use one or more of these vulcanization accelerating aids, and it is more preferable to use zinc oxide. The content of the vulcanization accelerating aid is, for example, 3 parts by mass or more and 15 parts by mass or less based on 100 parts by mass of the rubber component.

[0027] Examples of the antiaging agent include benzimidazole-based agents, aromatic secondary amine-based agents, amine-ketone-based agents, etc. It is preferable to use one or more of these antiaging agents, and it is more preferable to use a combination of benzimidazole-based agents and aromatic secondary amine-based agents. The content of the antioxidant is, for example, 1.5 parts by mass or more and 3.5 parts by mass or less based on 100 parts by mass of the rubber component.

[0028] Examples of the reinforcing material include carbon black and silica. Examples of the carbon black include channel black, furnace black such as SAF, ISAF, N-339, HAF, N-351, MAF, FEF, SRF, GPF, ECF, and N-234, thermal black such as FT and MT, and acetylene black. These may be used alone or in combination of two or more kinds. As the carbon black, it is preferable to use at least FEF or HAF. The reinforcing material may be a combination of carbon black and silica.

[0029] When carbon black is used as the reinforcing material, the content is, for example, 10 parts by mass or more and 80 parts by mass or less per 100 parts by mass of the rubber component. The content of the carbon black is preferably 45 parts by mass or more and 70 parts by mass or less per 100 parts by mass of the rubber component. When silica is used as the reinforcing material, the content thereof is, for example, 10 parts by mass or more and 80 parts by mass or less per 100 parts by mass of the rubber component.

[0030] Examples of the plasticizer include polyether esters, dialkyl sebacates such as dioctyl sebacate (DOS), dialkyl phthalates such as dibutyl phthalate (DBP) and dioctyl phthalate (DOP), dialkyl adipates such as dioctyl adipate (DOA), etc. These may be used alone or in combination of two or more kinds. As the plasticizer, it is preferable to use at least a polyether ester. The amount of the plasticizer is, for example, 5 parts by mass or more and 15 parts by mass or less per 100 parts by mass of the rubber component.

[0031] Examples of the co-crosslinking agent include trimethylolpropane trimethacrylate, m-phenylenedimaleimide, zinc dimethacrylate, triallyl isocyanurate, etc. These may be used alone or in combination of two or more kinds. As the co-crosslinking agent, it is preferable to use trimethylolpropane trimethacrylate and m-phenylenedimaleimide in combination. The content of the co-crosslinking agent is, for example, 3 parts by mass or more and 8 parts by mass or less based on 100 parts by mass of the rubber component.

[0032] Examples of the crosslinking agent include sulfur, organic peroxides, etc. Either one of the two may be used alone, or they may be used in combination. When only an organic peroxide is used as the crosslinking agent, the mixing amount of the organic peroxide is, for example, 2 parts by mass or more and 10 parts by mass or less per 100 parts by mass of the rubber component. In addition, when sulfur and an organic peroxide are used in combination as the crosslinking agent, the total compounding amount of the crosslinking agents is, for example, 0.1 part by mass or more and 0.7 parts by mass or less of sulfur and 1 part by mass or more and 5 parts by mass or less of the organic peroxide per 100 parts by mass of the rubber component.

[0033] In addition, the belt body 11 may be composed of a composition containing a thermosetting urethane elastomer in which an uncured thermosetting urethane composition in which a urethane prepolymer and a curing agent are mixed with various compounding agents is heated and pressurized during belt molding to crosslink the urethane prepolymer. Furthermore, the belt body 11 may be made of a thermoplastic elastomer composition obtained by blending various compounding ingredients with a thermoplastic elastomer and molding the thermoplastic elastomer composition in a mold.

[0034] The core wire 13 is embedded in the surface layer on the inner circumferential side of the back rubber portion 11a of the belt body 11 so as to extend in a spiral shape having a pitch in the belt width direction.

[0035] The core wire 13 has a diameter of 0.50 mm or more and 0.60 mm or less. The pitch of the core wires 13 (the arrangement pitch in the belt width direction) is 0.70 mm or more and 0.85 mm or less. When the core wire 13 satisfies these conditions, the toothed belt 10 has good positioning properties while reducing the belt bending rigidity. Also, the responsiveness of the toothed belt 10 is easily ensured.

[0036] In particular, in an embodiment of the present invention, a core wire containing carbon fiber that can ensure sufficient tension even though it is thin is used as the core wire, thereby achieving a thin core wire diameter of 0.50 mm or more and 0.60 mm or less while narrowing the core wire arrangement pitch to 0.70 mm or more and 0.85 mm or less. Therefore, the toothed belt according to the embodiment of the present invention has excellent positioning properties even though it is a relatively small toothed belt.

[0037] The core wire 13 includes carbon fiber as a constituent material. The core wire 13 may be composed of only carbon fiber, or may be composed of a combination of carbon fiber and other types of fiber. The carbon fiber may be PAN-based, may be pitch-based, or may contain both. A sizing agent such as epoxy resin may be attached to the carbon fiber. Examples of the other types of fibers include inorganic fibers such as glass fibers and metal fibers, and organic fibers such as aramid fibers, polyester fibers, PBO fibers, nylon fibers, and polyketone fibers.

[0038] When the core wire 13 contains carbon fiber and other types of fiber as its constituent materials, the proportion of carbon fiber to all fibers is 50 mass % or more. The proportion of the carbon fibers is preferably as high as possible (for example, 90% by mass or more), and may be 100%.

[0039] The carbon fiber has a filament diameter of 4 μm or more and 6 μm or less. By using a core wire containing carbon fibers having the above filament diameter, the toothed belt 10 has good positioning properties.

[0040] The core wire 13 is a twisted yarn of 5000 to 7000 filaments including the carbon fiber. By using such a twisted yarn as the core wire, the toothed belt 10 has good positioning properties.

[0041] The stranding of the core wire 13 may be single-twisted, double-twisted, or rung-twisted. Among these stranding methods, single-twisted is preferred from the viewpoints of strength, elastic modulus, and adhesive treatment of the filaments constituting the core wire.

[0042] When the core wire 13 is a single-twisted yarn, the number of single twists is 4 to 10 times per 10 cm. If the number of single twists is less than 4 times per 10 cm, the bending fatigue is poor and the core wire is not suitable for a toothed belt. On the other hand, if the number of single twists exceeds 10 times per 10 cm, the strength and elastic modulus decrease, and the positioning of the toothed belt using this core wire becomes poor.

[0043] When the core wire 13 is a ply yarn or a lange twist yarn, the number of final twists is 4 to 8 times per 10 cm. If the number of final twists is less than 4 times per 10 cm, the bending fatigue resistance is poor and the core wire is not suitable for a toothed belt. On the other hand, if the number of final twists exceeds 10 times per 10 cm, the strength and elastic modulus decrease, and the positioning of the toothed belt using this core wire becomes poor. When the core wire 13 is a ply or rung twist, the number of times of first twist is not particularly limited, but is, for example, 6 to 12 times / 10 cm.

[0044] The core wires 13 may be subjected to an adhesive treatment before the toothed belt 10 is produced in order to increase the adhesive strength between the core wires 13 and the belt body 11 . As the above-mentioned adhesive treatment, for example, one or both of an RFL treatment in which the substrate is immersed in an RFL aqueous solution followed by heating and a rubber paste treatment in which the substrate is immersed in rubber paste followed by drying, a treatment in which the substrate is immersed in an aqueous treatment agent containing rubber latex and a crosslinking agent followed by drying, etc. can be used. The aqueous treatment agent is mainly composed of rubber latex. The rubber latex may contain at least one rubber component selected from the group consisting of nitrile rubber, hydrogenated nitrile rubber, carboxyl-modified nitrile rubber, and carboxyl-modified hydrogenated nitrile rubber. The aqueous treatment agent may or may not contain an RFL condensate. Prior to the above-mentioned adhesion treatment, the core wires 13 may be subjected to a surface preparation treatment in which the core wires 13 are immersed in an epoxy solution or an isocyanate solution and then heated.

[0045] When the core wire 13 is a single-twist yarn, the core wire can be obtained, for example, by twisting a fiber bundle of carbon fiber alone, or a fiber bundle of carbon fiber and another type of fiber, in one direction (S direction or Z direction) with the above-mentioned number of single twists.

[0046] When the core wire 13 is a ply yarn, the core wire can be obtained, for example, by collecting multiple ply yarns each of which is made by plying a plurality of fiber bundles, including fiber bundles of carbon fibers, in one direction (S direction or Z direction), and then plying the ply yarns in the direction opposite to the ply twist direction with the above-mentioned number of ply twists.

[0047] When the core wire 13 is a Lang twisted yarn, the core wire can be obtained, for example, by collecting a plurality of first twisted yarns, each of which is made by first twisting a plurality of fiber bundles, including fiber bundles of carbon fibers, in one direction (S direction or Z direction), and then twisting the first twist in the same direction as the first twist direction with the above number of final twists.

[0048] In the toothed belt 10, the core wires 13 may be of two types, S-twisted yarn (in the case of ply-twisted yarn or Lang-twisted yarn, the upper twist direction is S direction) and Z-twisted yarn (in the case of ply-twisted yarn or Lang-twisted yarn, the upper twist direction is Z direction), and may be arranged in a double helix shape so that they are alternately arranged in the belt width direction. In this case, it is suitable for suppressing deviation of the toothed belt 10 while it is running. The core wire 13 may be constructed from a single S-stranded or Z-stranded yarn.

[0049] The reinforcing cloth 14 is applied so as to cover the inner peripheral surface on which the multiple toothed rubber portions 11b of the belt body 11 are provided. Therefore, the toothed rubber portions 11b of each belt tooth 12 are covered with the reinforcing cloth 14. At the tooth bottom portion 15, the reinforcing cloth 14 is disposed immediately inside the core wire 13 embedded in the inner peripheral portion of the back rubber portion 11a of the belt body 11. The thickness of the reinforcing cloth 14 is, for example, 0.1 mm or more and 0.6 mm or less.

[0050] The reinforcing fabric 14 is made of, for example, a woven fabric, knitted fabric, or nonwoven fabric formed from yarns such as nylon fibers (polyamide fibers), polyester fibers, aramid fibers, polyparaphenylenebenzobisoxazole (PBO) fibers, cotton, etc. Among these, a woven fabric made of nylon fibers is preferable. The reinforcing fabric 14 is preferably elastic, for example, a woven fabric in which the weft yarn is subjected to a wooly finish or the like.

[0051] The reinforcing cloth 14 may be subjected to one or more of the following adhesion treatments to increase the adhesive strength with the belt body: an RFL treatment in which the reinforcing cloth 14 is immersed in an RFL aqueous solution and then heated; a soaking treatment in which the reinforcing cloth 14 is immersed in low-viscosity rubber paste and then dried; and a coating treatment in which high-viscosity rubber paste is applied to the surface of the belt body side and then dried. Prior to the above-mentioned adhesion treatment, the reinforcing fabric 14 may be subjected to a preliminary treatment in which the fabric is immersed in an epoxy solution or an isocyanate solution and then heated.

[0052] The toothed belt 10 has a bending stiffness of 7.33 Ncm 2 It is preferable that: In this case, since the toothed belt 10 can be bent with a small force when it is wound around the pulley, there is no need to apply high tension to the belt, and the rigidity of the device can be reduced. Also, the lower the rigidity of the belt, the smaller the power transmission energy loss and the better the bending fatigue resistance and responsiveness of the belt. On the other hand, a toothed belt with a high bending rigidity has poor bending fatigue resistance and may not be suitable for use in combination with a small pulley. The lower limit of the bending stiffness is not particularly limited, but is, for example, 6.50 Ncm 2 It is.

[0053] The bending stiffness is measured by the following method. The bending stiffness E of the toothed belt 10 is obtained by a bending test using an Olsen bending tester in accordance with JIS K7106 (1995), and the bending stiffness E is multiplied by the second moment of area I of the toothed belt 10 to calculate the belt bending stiffness E·I. Here, the second moment of area I of the toothed belt 10 is expressed as I=bh, where the belt width is the width b of the test piece, the belt thickness at the tooth bottom portion 15 is the thickness h of the test piece, and the cross section of the toothed belt 10 is rectangular. 3 / 12 In other words, in the present invention, the secondary moment is calculated while ignoring the tooth rubber portion of the toothed belt 10.

[0054] The toothed belt 10 preferably has an elastic modulus M1.0 of 300 N / mm or more. In this case, it is more suitable to ensure good positioning. A preferred upper limit of the elastic modulus M1.0 is 1000 N / mm. If the elastic modulus M1.0 is too large, plastic deformation may occur, and the strength of the belt may decrease.

[0055] In an embodiment of the present invention, the elastic modulus M1.0 of a toothed belt refers to the stress per unit width of the belt when the toothed belt is stretched by 1.0% in the belt length direction in a tensile test conducted using the toothed belt as a measurement sample.

[0056] The elastic modulus M1.0 is measured by the following method using a tensile tester. First, the toothed belt 10 is cut into a strip having a belt length of about 300 mm, and two benchmark lines spaced apart by about 100 mm are marked on the back surface of the toothed belt 10 to prepare a measurement sample. Next, both ends of the measurement sample in the belt length direction are gripped by the chucks of a tension tester, and the measurement sample is set in the tensile tester. Thereafter, the measurement sample is pulled in the belt length direction at a pulling speed of 50 mm / min, and the stress when the measurement sample is elongated by 1.0% based on the gauge length is detected by a load cell. Finally, the detected stress is divided by the width of the measurement sample to calculate the stress per unit width. The measurement is carried out three times, and the average value is regarded as the elastic modulus M1.0.

[0057] In the toothed belt 10, the hardness (JIS-A) of the rubber composition or elastomer composition constituting the belt body 11 is preferably 84 to 94. If the belt body 11 satisfies this requirement, it is suitable for improving bending fatigue resistance and responsiveness while ensuring excellent positioning properties. On the other hand, if the hardness (JIS-A) is less than 84, the positioning ability of the toothed belt 10 may be poor. If the hardness (JIS-A) is more than 94, the toothed belt 10 may be poor in bending fatigue resistance and responsiveness.

[0058] The hardness (JIS-A) of the rubber composition or elastomer composition is determined by molding the rubber composition or elastomer composition constituting the belt body 11 into a predetermined shape, using this as a measurement sample, and measuring the hardness using a type A durometer in accordance with JIS K6253-3 (2012) or JIS K7312 (1996) depending on the object to be measured.

[0059] The gap ratio of the toothed belt 10 is preferably less than 30%, which improves the positioning ability of the toothed belt 10. The gap ratio is more preferably 28% or less. The above gap ratio may be small from the viewpoint of positioning, but if it is too small, the occurrence rate of defective products in which the rubber composition is not filled in the tooth rubber portion during the manufacture of the toothed belt may increase. Therefore, from the viewpoint of yield, the lower limit of the above gap ratio is preferably 20%, and more preferably 22%. The above-mentioned gap ratio refers to the ratio (%) of the total gap dimensions between the core wires in the width direction of the belt to the width dimension of the toothed belt. The smaller the gap ratio, the greater the proportion of the cord in the width direction of the belt.

[0060] The toothed belt 10 according to the embodiment of the present invention is wound around, for example, a pair of pulleys and transmits power from a drive source to a driven side. Here, the outer diameter of the pulley is, for example, 21.32 mm or more and 94.53 mm or less. The belt running speed is, for example, 0.1 m / sec or more and 33.0 m / sec or less, and the transmission capacity is, for example, 0.05 kW or more and 20.10 kW or less.

[0061] According to the toothed belt 10 of this embodiment having the above-mentioned configuration, the core wire 13 has a specific configuration containing carbon fiber, and this core wire 13 is embedded in the belt body 11 at a predetermined arrangement pitch, so that it has excellent positioning ability and good responsiveness.

[0062] Next, a method for producing the toothed belt 10 according to the present embodiment will be described with reference to Figs. 4 to 7, taking as an example a case in which the belt body is made of the above-mentioned rubber composition. The method for manufacturing the toothed belt 10 includes a material preparation step, a molding step, a vulcanization step, and a finishing step.

[0063] <Material preparation process> A predetermined rubber component is masticated, and various rubber compounding agents are added thereto and kneaded to obtain an unvulcanized rubber composition. The unvulcanized rubber composition thus obtained is then calendered or otherwise molded to produce an unvulcanized rubber composition sheet 11'.

[0064] An adhesive treatment is applied to each of the core wires 13 and the reinforcing cloth 14. The reinforcing cloth 14 is then formed into a cylindrical shape.

[0065] <Forming process> FIG. 4 is a partial cross-sectional view showing a part of the belt forming die 30. As shown in FIG. The belt forming die 30 is cylindrical and has an outer circumferential surface on which a plurality of teeth forming grooves 31 are formed and spaced apart in the circumferential direction so as to extend in the axial direction.

[0066] As shown in FIG. 5, a cylindrical reinforcing cloth 14 is placed on the outer circumferential surface of a belt forming mold 30, and a core wire 13 is wound around the reinforcing cloth 14 in a spiral shape. Then, an unvulcanized rubber composition sheet 11' is wrapped around it, and an unvulcanized slab S' is molded on the belt molding die 30. The unvulcanized rubber composition sheet 11' is preferably used so that the grain direction corresponds to the belt length direction.

[0067] <Vulcanization process> As shown in Fig. 6, the unvulcanized slab S' on the belt mold 30 is covered with a rubber sleeve 32, which is then placed in a vulcanizer can and sealed, and the vulcanizer can is filled with high-temperature, high-pressure steam and held for a specified molding time. In this way, the unvulcanized slab S' is pressed against the belt mold 30 and heated, whereby the unvulcanized rubber composition sheet 11' is passed between the cords 13 and flows into each of the multiple tooth-forming grooves 31 of the belt mold 30 while pressing the reinforcing cloth 14, and vulcanized. At the same time, the cords 13 and the reinforcing cloth 14 are integrated and compounded, and finally, a cylindrical belt slab S is molded as shown in Fig. 7.

[0068] <Finishing process> The pressure inside the vulcanizer is reduced to release the seal, and the belt slab S molded between the belt mold 30 and the rubber sleeve 32 is taken out and demolded, and then cut into rings of a specified width to obtain the toothed belt 10. Through these steps, the toothed belt 10 having the belt body made of the rubber composition can be manufactured.

[0069] The toothed belt 10 having the belt body 11 made of a thermosetting urethane elastomer composition or a thermosetting elastomer composition can be manufactured, for example, by the following method. That is, (1) The core wire 13 is wound spirally around the outer circumferential surface of a cylindrical belt forming die 30 that has been used in the manufacture of a toothed belt having a belt body made of a rubber composition. (2) Next, the cylindrical belt forming die 31 is placed in a cylindrical outer die having an inner diameter larger than the outer diameter of the belt forming die 31. At this time, a cavity for forming the belt main body is formed between the belt forming die 31 and the outer die.

[0070] (3-1) Next, an uncured thermosetting urethane composition containing a urethane prepolymer and a curing agent is injected into the cavity, filling it and heating it. At this time, the uncured thermosetting urethane composition hardens while also entering the teeth forming grooves 31, and a cylindrical slab in which the thermosetting urethane elastomer and the core wires 13 are integrated is formed. (3-2) Alternatively, the thermoplastic elastomer composition that has been made fluid by heating is injected into the cavity, which is then cooled. At this time, the thermoplastic elastomer solidifies while also entering the tooth-forming grooves 31, and a cylindrical slab in which the thermoplastic elastomer and the core wires 13 are integrated is formed.

[0071] (4) Then, the cylindrical slab is removed from the belt molding die 31 and the outer die, and a reinforcing cloth is attached to its inner surface (the toothed rubber portion side). The slab with the reinforcing cloth is then cut into rings to obtain the toothed belt 10. By carrying out these steps, it is possible to manufacture the toothed belt 10 whose belt body is made of a thermosetting urethane elastomer composition or a thermosetting elastomer composition. EXAMPLES

[0072] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0073] Examples 1 to 3 and Comparative Examples 1 to 4 Here, a toothed belt with a tooth type of S5M (JIS B1857) was produced and its performance was evaluated. Each toothed belt was produced by the method described above. The unvulcanized rubber composition, core wire, and reinforcing fabric for forming the belt body (back rubber portion and tooth rubber portion) were prepared as follows.

[0074] (Preparation of Unvulcanized Rubber Composition) The following rubber compositions A to D were prepared, each having the composition shown in Table 1. In Table 1, the blending amounts are shown in parts by mass. Rubber composition A: A base rubber was prepared by mixing 45 parts by mass of hydrogenated nitrile rubber (H-NBR) (manufactured by Zeon Corporation, product name: Zettopole 2020) and 55 parts by mass of hydrogenated nitrile rubber containing an unsaturated carboxylate metal salt (manufactured by Zeon Corporation, product name: ZSC2195) which is a mixture of an unsaturated carboxylate metal salt and 5 parts by mass of zinc oxide (manufactured by Sakai Chemical Industry Co., Ltd., product name: Zinc Oxide Type 3), stearic acid (Nippon Zeon Co., Ltd.), and 100 parts by mass of the base rubber. An unvulcanized rubber composition was prepared by blending and kneading 1 part by mass of stearic acid (manufactured by Honrika Co., Ltd., trade name: stearic acid), 10 parts by mass of dioctyl sebacate (DOS) (manufactured by Dainippon Ink and Chemicals Incorporated Co., Ltd., trade name: Monosizer W280), 60 parts by mass of carbon black FEF (manufactured by Tokai Carbon Co., Ltd., trade name: Seest SO), 3 parts by mass of an antioxidant (manufactured by Ouchi Shinko Chemical Co., Ltd., trade name: Nocrac MB), 3 parts by mass of trimethylolpropane triacrylate (TMPT) (manufactured by Sanshin Chemical Industry Co., Ltd., trade name: Sunester TMP), and 7 parts by mass of Peroximon F40 (manufactured by NOF Corporation), to obtain a rubber composition A.

[0075] Regarding the rubber composition A, the hardness (JIS-A) of the vulcanizate vulcanized under the same vulcanization conditions as those used in producing the toothed belt was measured and found to be 89. The hardness of the vulcanizate was measured using a type A durometer in accordance with JIS K6253-3 (2012). The hardness of the vulcanizates of the following rubber compositions B to D was measured in the same manner.

[0076] Rubber composition B: Prepared in the same manner as rubber composition A, except that the proportion of carbon black FEF was changed. Regarding the rubber composition B, the hardness (JIS-A) of the vulcanizate vulcanized under the same vulcanization conditions as those used in producing the toothed belt was measured and found to be 86.

[0077] Rubber composition C: Prepared in the same manner as rubber composition A, except that the proportion of carbon black FEF was changed. Regarding the rubber composition C, the hardness (JIS-A) of the vulcanizate vulcanized under the same vulcanization conditions as those used in producing the toothed belt was measured and found to be 95.

[0078] Rubber composition D: prepared in the same manner as rubber composition A, except that the proportion of carbon black FEF was changed. Regarding the rubber composition D, the hardness (JIS-A) of the vulcanizate vulcanized under the same vulcanization conditions as those used in producing the toothed belt was measured and found to be 80.

[0079] [Table 1]

[0080] (Preparing the core wire) Core Wire A: Carbon fiber (manufactured by Toray Industries, product name: Torayca T800HB-6000, filament diameter 5.0 μm, number of filaments 6000) was used, and this was twisted 6 times per 10 cm to form a single twist yarn, which was used as core wire A. The core wire diameter of core wire A was 0.55 mm. Two types of core wire A were prepared: S twist yarn and Z twist yarn.

[0081] Core Wire B: Carbon fiber (manufactured by Toray Industries, product name: Torayca T800HB-6000, filament diameter 5.0 μm, number of filaments 6000) was used, and this was twisted 8 times per 10 cm to form a single twist yarn, which was used as core wire B. The core wire diameter of core wire B was 0.58 mm. Two types of core wire B were prepared: S twist yarn and Z twist yarn.

[0082] Core Wire C: Carbon fiber (manufactured by Toray Industries, product name: Torayca T300B-6000, filament diameter 7.0 μm, number of filaments 6000) was used, and this was twisted 7.5 times per 10 cm to form a single twist yarn, which was used as core wire C. The core wire diameter of core wire C was 0.70 mm. Two types of core wire C were prepared: S twist yarn and Z twist yarn.

[0083] Core Wire D: Carbon fiber (manufactured by Toray Industries, product name: Torayca T300B-3000, filament diameter 7.0 μm, number of filaments 3000) was used, and this was twisted 6 times per 10 cm to form a single twist yarn, which was used as core wire D. The core wire diameter of core wire D was 0.48 mm. Two types of core wire D were prepared: S twist yarn and Z twist yarn.

[0084] Wire E: Carbon fiber (manufactured by Toray Industries, product name: Torayca T300B-3000, filament diameter 7.0 μm, number of filaments 3000) was used, and this was twisted 12 times per 10 cm to form a single-twisted yarn, which was used as wire E. The wire diameter of wire E was 0.53 mm. Two types of wire E were prepared: S-twisted yarn and Z-twisted yarn.

[0085] Core Wire F: High-hardness glass fiber (high-strength glass cord manufactured by Nippon Sheet Glass, filament diameter 7.0 μm) was used, and three strands of 200 filaments were collected together and twisted in one direction with a first twist of 8 times / 10 cm to create eight first twisted yarns, which were then twisted in the opposite direction to the first twist with a final twist of 8 times / 10 cm to create core wire F. The core wire diameter of core wire F is 0.72 mm. Two types of core wire F were prepared: S twisted yarn and Z twisted yarn. The total number of filaments in core wire F is 4,800.

[0086] (Preparation of reinforcing fabric) The following nylon canvas was prepared as the reinforcing fabric. Resorcinol (Sumitomo Chemical Co., Ltd., product name: Resorcinol) and formalin (Mitsui Chemicals, Inc., product name: Formalin) were added to a sodium hydroxide solution in a molar ratio of R / F = 1 / 2 and mixed with stirring to obtain an initial condensation product solution. Hydrogenated acrylonitrile butadiene methacrylic acid terpolymer (X-NBR) latex (Zeon Corporation, product name: ZLX-B) and water were added to the resulting solution and mixed with stirring to prepare an RFL liquid with a mass ratio of resorcinol-formalin to latex RF / L = 1 / 8.

[0087] Next, 80 parts by mass of polytetrafluoroethylene (manufactured by Asahi Glass Co., Ltd., product name: Fluon AD911, average particle size: 0.25 μm) and 30 parts by mass of blocked isocyanate (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., product name: Elastron BN-27, bond dissociation temperature 180°C) were added to this RFL liquid per 100 parts by mass of the latex solids content of the RFL liquid and mixed by stirring, and further carbon black (manufactured by Fuji Pigment Industry Co., Ltd., product name: Fuji SP Black 203) was added and dispersed to make up 5% by mass of the total, preparing a treatment liquid with a solids concentration of 15% by mass.

[0088] A 2 / 2 twill fabric made of woolly processed 6,6-nylon fiber with a warp thread of 235 dtex and a weft thread of 155 dtex (breaking elongation of 150% or more) was immersed in this treatment solution, then pulled out and passed between a pair of pressure rolls and squeezed to apply the treatment solution to the twill fabric. The temperature of the treatment solution was 20°C, the immersion time was 2 seconds, and the treatment was repeated twice. The clearance of the pressure rolls was adjusted so that the basis weight of the RFL coating was about 30% by mass.

[0089] The twill fabric with the treatment solution was passed through a heating and drying oven and dried to prepare nylon canvas. The oven temperature (heating and drying temperature) was 150° C. and the heat treatment time was 2 minutes. This nylon canvas was used as the reinforcing fabric in the examples and comparative examples.

[0090] <Example 1> Using rubber composition A as the unvulcanized rubber composition forming the belt body, core wire A as the core wire, and the above-mentioned nylon canvas as the reinforcing cloth, a toothed belt with a tooth type of S5M was manufactured by the above-mentioned manufacturing method (see Figs. 4 to 7). The belt width was 10 mm, and the belt length was 800 mm. At this time, the core wire A used was one that had been immersed in aqueous treatment agent A containing a crosslinking agent and a rubber latex that was mainly composed of hydrogenated nitrile rubber and did not contain RFL condensate, and then dried for adhesion treatment. The core wire A was arranged in a double helix with S twisted yarn and Z twisted yarn alternately arranged in the belt width direction and the pitch between adjacent core wires was 0.75 mm. The gap ratio of the manufactured toothed belt is 26.7%.

[0091] <Example 2> A toothed belt was produced in the same manner as in Example 1, except that rubber composition B was used instead of rubber composition A as the unvulcanized rubber composition.

[0092] <Example 3> A toothed belt was produced in the same manner as in Example 1, except that rubber composition C was used instead of rubber composition A as the unvulcanized rubber composition.

[0093] <Example 4> A toothed belt was produced in the same manner as in Example 2, except that the core wire B was used instead of the core wire A. At this time, the core wire B used was immersed in the above-mentioned aqueous treatment agent A and then dried for adhesion treatment. The core wire B was arranged in a double helix such that the S twisted yarn and the Z twisted yarn were alternately arranged in the belt width direction and the pitch between adjacent core wires was 0.75 mm. The gap ratio of the manufactured toothed belt was 22.7%.

[0094] <Comparative Example 1> Using rubber composition D as the unvulcanized rubber composition forming the belt body, core wire C as the core wire, and the above-mentioned nylon canvas as the reinforcing cloth, a toothed belt with a tooth type of S5M was manufactured by the above-mentioned manufacturing method (see Figs. 4 to 7). The belt width was 10 mm, and the belt length was 800 mm. At this time, the core wire C used was one that had been subjected to an adhesive treatment by immersing it in the above-mentioned aqueous treatment agent A and then drying it. The core wire C was arranged in a double helix such that the S twisted yarn and the Z twisted yarn were alternately arranged in the belt width direction and the pitch between adjacent core wires was 1.0 mm. The gap ratio of the toothed belt is 30.0%.

[0095] <Comparative Example 2> A toothed belt was produced in the same manner as in Example 1, except that core wire D was used instead of core wire A as the core wire, and the following core wire pitch was adopted. At this time, the core wire D used was immersed in the above-mentioned aqueous treatment agent A and then dried for adhesion treatment. The core wire D was arranged in a double helix such that the S twisted yarn and the Z twisted yarn were alternately arranged in the belt width direction and the pitch between adjacent core wires was 0.80 mm. The gap ratio of the manufactured toothed belt is 40.0%.

[0096] <Comparative Example 3> A toothed belt was produced in the same manner as in Example 1, except that core wire E was used instead of core wire A as the core wire, and the following core wire pitch was adopted. At this time, the core wire E used was one that had been subjected to an adhesive treatment by immersing it in the above-mentioned aqueous treatment agent A and then drying it. The core wire E was arranged in a double helix such that the S twisted yarn and the Z twisted yarn were alternately arranged in the belt width direction and the pitch between adjacent core wires was 0.80 mm. The gap ratio of the manufactured toothed belt is 33.8%.

[0097] <Comparative Example 4> A toothed belt was produced in the same manner as in Example 3, except that core wire F was used instead of core wire A as the core wire, and the following core wire pitch was adopted. At this time, the core wire F used was one that had been subjected to an adhesive treatment by immersing it in the above-mentioned aqueous treatment agent A and then drying it. The core wire F was arranged in a double helix such that the S twisted yarn and the Z twisted yarn were alternately arranged in the belt width direction and the pitch between adjacent core wires was 1.2 mm. The gap ratio of the manufactured toothed belt is 40.0%.

[0098] (Evaluation method) The toothed belts manufactured in the examples and comparative examples were measured for bending rigidity and elastic modulus M1.0. Furthermore, the toothed belts manufactured in the examples and comparative examples were evaluated for positioning ability and responsiveness. These results are shown in Table 3.

[0099] <Bending rigidity> The bending stiffness was measured by the above-mentioned method using a toothed belt cut to a length of 70 mm as a sample. That is, for a measurement sample of a toothed belt, the bending stiffness E is obtained by a bending test using an Olsen bending tester in accordance with JIS K7106 (1995), and this is multiplied by the moment of inertia I of the toothed belt to obtain the belt bending stiffness E·I (Ncm 2 ) was calculated.

[0100] The measurement sample of the toothed belt had a tooth shape of S5M, a width of 10 mm, a thickness of 3.61 mm, and a length of 70 mm. The moment of inertia I of the measurement sample of a toothed belt is assumed to be rectangular, ignoring the teeth of the toothed belt cross section. The width b of the test piece is the belt width of 10 mm, the thickness h of the test piece is the belt thickness at the tooth bottom of 1.70 mm, and the moment of inertia I is calculated as I=bh 3 This was calculated by multiplying the square root of the square root by 12.

[0101] In addition, the parameters of equation (6) for calculating the bending stiffness E described in 8.3 of JIS K7106 (1995) for the measurement sample of the toothed belt were: distance between supports S: 1.27 cm, width of test piece b: 10 mm, thickness of test piece: 3.61 mm, pendulum moment M0 at 100% load scale: 0.0846 N m, bending angle φ: 0.1745 rad. The tests were carried out at room temperature of 25±5°C and humidity of 50±5%.

[0102] <Elastic modulus M1.0> The elastic modulus M1.0 was measured using a tensile tester by the method described above. The tensile speed was 50 mm / min. The measurement was carried out three times, and the average value was taken as the elastic modulus M1.0.

[0103] <Positioning ability> FIG. 8 shows the pulley layout of the belt testing machine 100. The belt testing machine 100 comprises a drive pulley 120 fixed to a rotating shaft and a driven pulley 130 fixed to a fixed shaft so as not to rotate, which are arranged at a laterally spaced interval. A torque meter is connected to the rotating shaft of the drive pulley 120, and the drive pulley 120 can be rotated by applying a torque to this rotating shaft. At a position M above the drive pulley 120, the amount of movement (rotation angle deg) on ​​the pitch line of the toothed belt 110 can be measured.

[0104] This evaluation was performed according to the following procedure by wrapping the toothed belts 110 manufactured in the examples and comparative examples around the driving pulley 120 and driven pulley 130 of a belt testing machine 100. In this evaluation, the rotational torque that rotates the driving pulley 120 to the right is defined as +torque, and the rotational torque that rotates the driving pulley 120 to the left is defined as -torque. The settings for the evaluation are as shown in Table 2.

[0105] [Table 2]

[0106] (1) The state before the drive pulley 120 is rotated is defined as the initial state. (2) A torque of −15 Nm is applied to rotate the drive pulley 120 counterclockwise, and the amount of movement of the toothed belt 110 on the pitch line at that time is measured. (3) The torque applied to the drive pulley 120 is released, and the amount of movement of the toothed belt 110 on the pitch line at that time is measured. (4) A torque of +15 Nm is applied to rotate the drive pulley 120 clockwise, and the amount of movement of the toothed belt 110 on the pitch line at that time is measured. (5) The torque applied to the drive pulley 120 is released, and the amount of movement (displacement angle deg) of the toothed belt 110 on the pitch line at that time is measured. (6) Such measurements (1) to (5) constitute one set. This set is repeated three times.

[0107] When one set of such measurements is performed, the relationship between the rotational torque and the amount of movement on the pitch line of the toothed belt 110 (amount of displacement from the initial state) can be shown as in the graph of FIG. FIG. 9 is a graph of the first set of data obtained in the evaluation of positioning ability in Example 1. In the graph of FIG. 9, the states at the end of steps (1) to (5), respectively, correspond to A to E. In this evaluation, the difference between C and E in Fig. 9 was used as the standard, and it was determined that the smaller this difference was, the better the positioning performance was. This is because the smaller the difference between C and E is, the closer the position returns to the initial state each time the torque is released. The rotation angle of the drive pulley, which corresponds to the difference between CE, is listed as the evaluation value in Table 3. The evaluation value is also the average value of three sets. In this case, the smaller the rotation angle, the shorter the distance between CE, and the better the positioning performance.

[0108] <Responsiveness> FIG. 10 shows the pulley layout of the belt testing machine 200. The belt testing machine 200 has a driving pulley 220 and a driven pulley 230 arranged at a distance in the horizontal direction, and is configured so that the driven pulley can be moved in the horizontal direction to fix the set weight SW. The belt testing machine 200 also includes an encoder (not shown) for acquiring the number of rotations of the driving pulley 220 and the driven pulley 230. Both the driving pulley 220 and the driven pulley 230 have 24 teeth and are of the S5M type.

[0109] In this evaluation, the toothed belt 210 manufactured in the examples and comparative examples was wound around the driving pulley 220 and the driven pulley 230 of the belt testing machine 200, and the set weight of the driven pulley 230 was fixed so that a belt tension of 45 N was applied to the toothed belt 210. In addition, the flywheel effect (GD 2 ) is 0.040 kgf m 2 It is. Next, at room temperature, the driving pulley 220 was accelerated from 0 to 100 rpm in an acceleration time of 0.02 seconds, and then driven at a constant speed of 100 rpm, and the rotation speeds of the driving pulley 220 and the driven pulley 230 were measured.

[0110] The test conditions for this evaluation are summarized as follows: ·Acceleration time: 0.02sec Rotation speed: 0 to 100 rpm Flywheel effect (GD 2 ): 0.040kgf·m 2

[0111] After the measurement, the difference between the rotation speed of the driving pulley 220 and the rotation speed of the driven pulley 230 was obtained along the time axis, and the maximum absolute value of this difference was used as the evaluation value in this evaluation. In this evaluation, the smaller the evaluation value, the better the responsiveness of the toothed belt.

[0112] 11 and 12 are graphs showing examples of data obtained in this evaluation. FIG. 11 is a graph showing the evaluation results of the toothed belt of Example 2, illustrating the change over time in the rotation speed of each of the driving pulley 220 and the driven pulley 230. FIG. 12 is a graph showing the evaluation results of the toothed belt of Example 2, and shows the change over time of the difference in the number of rotations between the driving pulley 220 and the driven pulley 230. As can be seen from these graphs, the rotation speed of the driven pulley rises later than that of the driving pulley, and after it greatly exceeds the rotation speed of the driving pulley, it gradually synchronizes with the rotation speed of the driving pulley. Therefore, if the difference in rotation speed between the two is small when the rotation speed of the driven pulley greatly exceeds the rotation speed of the driving pulley at first, the toothed belt has good responsiveness.

[0113] [Table 3] [Explanation of symbols]

[0114] 10, 110, 120 Toothed belt 11 Belt body 11a Back rubber 11b Rubber teeth part 12 belt teeth 13 Core Wire 14 Reinforcement fabric 15 Tooth root 30 Belt forming mold 31 Tooth formation groove 32 Rubber sleeve 100, 200 Belt Testing Machine 120, 220 Drive pulley 130, 230 Driven pulley

Claims

1. A belt body having a plurality of teeth provided at a constant pitch on an inner circumference of the belt; a core wire embedded in the belt body so as to form a spiral having a pitch in the belt width direction along the belt length direction; Equipped with The core wire includes carbon fiber having a filament diameter of 4 to 6 μm as a constituent material, and is a twisted yarn of 5,000 to 7,000 filaments including the carbon fiber, The number of single twists or second twists of the twisted yarn is 4 to 10 per 10 cm; The diameter of the core wire is 0.50 to 0.60 mm, The pitch of the core wire is 0.70 to 0.85 mm. Toothed belt.

2. 2. The toothed belt according to claim 1, wherein the tooth pitch is 5 mm.

3. Bending stiffness: 7.33 Ncm ２ 3. A toothed belt according to claim 1, wherein:

4. 4. The toothed belt according to claim 1, wherein the elastic modulus M1.0 is 300 N / mm or more.

5. 5. The toothed belt according to claim 1, wherein the belt body is made of a rubber composition or an elastomer composition having a hardness (JIS-A) of 84 to 94.

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