Toothed belt

Abstract

A plurality of tooth part main bodies (112) of the toothed belt (B) are respectively covered by reinforcing cloth (13) to form tooth parts (10A). The kurtosis of the surface roughness of the surface of the reinforcing cloth (13) of the tooth portion (10A) is 2.15 or more.

Description

Technical Field

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

[0002] Toothed belts are used for various applications that synchronously transmit power. For example, Patent Document 1 discloses a toothed belt for machine tools, printing machines, textile machines, injection molding machines, etc. In order to suppress the hitting sound against the pulley, the arithmetic mean roughness of the uneven surface at the bottom of the teeth between the teeth is set to 5 to 25 μm.

[0003] Patent Document 1: International Publication No. 2016 / 047052 Summary of the Invention

[0004] The present invention relates to a toothed belt including a belt body and a reinforcing cloth. The belt body has a flat belt portion and a plurality of tooth body portions. The plurality of tooth body portions are integrally provided on one surface of the flat belt portion at constant intervals. The reinforcing cloth is provided to cover the surface of the belt body on the side where the plurality of tooth body portions are provided. Each of the plurality of tooth body portions is covered by the reinforcing cloth to form a tooth portion, and the kurtosis of the surface roughness of the surface of the reinforcing cloth of the tooth portion is 2.15 or more. Brief Description of the Drawings

[0005] Figure 1A is a perspective view of a section of the toothed belt of the embodiment;

[0006] Figure 1B is a front view observed in the arrow X direction along Figure 1A ;

[0007] Figure 1C is a front view observed in the arrow Y direction along Figure 1A ;

[0008] Figure 1D is a cross-sectional view (two tooth portions) taken along the ID-ID line of Figure 1B ;

[0009] Figure 2A is a weave pattern diagram of a 1 / 3 twill twill fabric;

[0010] Figure 2B is a weave pattern diagram of a 3 / 1 twill twill fabric;

[0011] Figure 3A is a weave pattern diagram of a five-harness two-over-one satin fabric;

[0012] Figure 3B is a weave pattern diagram of a five-harness three-over-one satin fabric;

[0013] Figure 4 is a cross-sectional view of a part of a belt forming die;

[0014] Figure 5A is the first explanatory drawing of the manufacturing method of the toothed belt according to the embodiment;

[0015] Figure 5B is the second explanatory drawing of the manufacturing method of the toothed belt according to the embodiment;

[0016] Figure 5C is the third explanatory drawing of the manufacturing method of the toothed belt according to the embodiment;

[0017] Figure 6A is a top view of the running belt test machine for measuring the running sound of the belt;

[0018] Figure 6B is a front view of the running belt test machine for measuring the running sound of the belt. Detailed Embodiment

[0019] Hereinafter, the embodiment will be described in detail with reference to the drawings.

[0020] Figures 1A to 1D Shows the toothed belt B according to the embodiment. The toothed belt B according to the embodiment is, for example, an annular meshing drive belt assembled on an electric power steering device of an automobile.

[0021] The toothed belt B according to the embodiment has a plurality of tooth portions 10A. The plurality of tooth portions 10A are arranged at regular intervals in the belt length direction, and are each formed to protrude toward the inner peripheral side of the belt. In the present application, the tooth portion 10A is a portion that protrudes 0.1 mm or more in the protruding direction of the tooth portion 10A with respect to the tooth bottom portion 10B between a pair of tooth portions 10A adjacent to each other in the belt length direction.

[0022] The tooth portion 10A is a so-called round tooth having a semicircular cross-sectional shape. The tooth portion 10A is a so-called helical tooth formed of a ridge, and the ridge is formed to extend in a direction inclined with respect to the belt width direction. It should be noted that the tooth portion 10A may also be formed of a ridge extending in the belt width direction, or may be other shapes such as trapezoidal teeth having a trapezoidal cross-sectional shape.

[0023] The belt circumference (the belt length on the belt pitch line L) of the toothed belt B according to the embodiment is, for example, 100 mm or more and 400 mm or less. The belt width is, for example, 4 mm or more and 30 mm or less. The maximum belt thickness is, for example, 1.1 mm or more and 3.0 mm or less.

[0024] The pitch P of the tooth portions 10A is, for example, 0.50 mm or more and 5.0 mm or less. The height of the tooth portions 10A is, for example, 0.50 mm or more and 2.0 mm or less. The height of the tooth portions 10A is defined by the dimension from the tooth bottom portion 10B to the top end of the tooth portions 10A. The width of the tooth portions 10A is, for example, 0.8 mm or more and 3.3 mm or less. The width of the tooth portions 10A is defined by the dimension in the belt length direction between the end portions of a pair of tooth bottom portions 10B that are adjacent to each other with the tooth portions 10A interposed therebetween. The inclination angle θ of the tooth portions 10A with respect to the belt width direction is, for example, greater than 0° and 15° or less.

[0025] The toothed belt B according to the embodiment includes a belt main body 11, a core wire 12, and a reinforcing cloth 13.

[0026] The belt main body 11 has a flat belt portion 111 and a plurality of tooth main bodies 112. The plurality of tooth main bodies 112 are integrally provided at intervals with a constant pitch on the inner peripheral side (one side) surface of the flat belt portion 111. The thickness of the flat belt portion 111 is, for example, 0.30 mm or more and 1.8 mm or less. The height of the tooth main bodies 112 is, for example, 0.50 mm or more and 2.0 mm or less. The height of the tooth main bodies 112 is defined by the dimension from the innermost peripheral portion of the core wire 12 buried in the flat belt portion 111 described later to the top end of the tooth main bodies 112.

[0027] The belt main body 11 is formed of a rubber composition obtained by the following method: various rubber additives including a crosslinking agent are added to a rubber component to obtain an uncrosslinked rubber composition, and the uncrosslinked rubber composition is heated and pressurized to crosslink the rubber component through the crosslinking agent, thereby obtaining the above rubber composition.

[0028] Examples of the rubber component of the rubber composition forming the belt main body 11 can include: hydrogenated nitrile rubber (H-NBR), chloroprene rubber (CR), chlorosulfonated polyethylene rubber (CSM), ethylene-α-olefin elastomer (ethylene propylene diene terpolymer (EPDM), etc.). Examples of the crosslinking agent can include organic peroxides and sulfur. Examples of the rubber additives other than the crosslinking agent can include: vulcanization acceleration aids, anti-aging agents, reinforcing materials, plasticizers, co-crosslinking agents, etc.

[0029] The core wire 12 is buried in a portion on the inner peripheral side of the flat belt portion 111 of the belt main body 11. The core wire 12 is arranged to form a helix having a pitch in the belt width direction. The outer diameter of the core wire 12 is, for example, 0.15 mm or more and 0.80 mm or less.

[0030] The core wire 12 is composed of a twisted wire made of glass fiber, aramid fiber, carbon fiber, metal fiber, etc. The core wire 12 is arranged such that an S-twisted wire and a Z-twisted wire form a double helix. It should be noted that the core wire 12 may also be composed of only a single S-twisted wire or Z-twisted wire. In order to bond with the belt main body 11, it is preferable to perform at least one bonding treatment of a so-called RFL treatment and a rubber paste treatment on the core wire 12. The RFL treatment is a treatment in which heating is performed after impregnation in an RFL aqueous solution, and the rubber paste treatment is a treatment in which drying is performed after impregnation in a rubber paste. Before the bonding treatment, a base treatment may also be performed on the core wire 12. The base treatment is a treatment in which heating is performed after impregnation in an epoxy solution or an isocyanate solution.

[0031] The reinforcing cloth 13 is arranged to cover the surface of the belt main body 11 on the side where the plurality of tooth part main bodies 112 are provided. The thickness of the reinforcing cloth 13 is, for example, 0.050 mm or more and 0.55 mm or less.

[0032] In the toothed belt B according to the embodiment, the tooth part 10A is constituted by each of the plurality of tooth part main bodies 112 of the belt main body 11 being covered by the reinforcing cloth 13. At the tooth bottom part 10B, the core wire 12 buried in the inner peripheral side part of the flat belt-shaped part 111 of the belt main body 11 is arranged immediately inside the reinforcing cloth 13.

[0033] In the toothed belt B according to the embodiment, the kurtosis (Sku) of the surface roughness of the surface of the reinforcing cloth 13 of the tooth part 10A is 2.15 or more. The kurtosis Sku of the surface roughness is an index of the sharpness of the convex part in the unevenness of the surface, and as defined in ISO25178, it is an index standardized by dividing the fourth power average value of the height from the average plane of the uneven surface by the fourth power of the root mean square value. The kurtosis Sku of the surface roughness can be measured using a contact / non-contact shape measuring instrument.

[0034] According to the toothed belt B according to the embodiment, by making the kurtosis Sku of the surface roughness of the surface of the reinforcing cloth 13 of the tooth portion 10A be 2.15 or more, the running noise can be suppressed to a small level. It is presumed that this is because when the sharpness of the convex portions among the unevenness on the surface of the reinforcing cloth 13 is high, columnar sound is not easily generated. Generally speaking, when the toothed belt meshes with the pulley and strikes, based on the same principle as the applause, air is discharged from between them at a specific vibration frequency, thereby generating the running noise. In contrast, in the toothed belt B according to the embodiment, it can be considered that: since the sharpness of the convex portions among the unevenness on the surface of the reinforcing cloth 13 in contact with the pulley is high, it becomes a form of hitting the pulley with the tip of a brush, and the air is discharged in a manner where the vibration frequency is dispersed, so the running noise is suppressed to a small level. From the viewpoint of suppressing the running noise to a small level, the kurtosis Sku of the surface roughness of the surface of the reinforcing cloth 13 of the tooth portion 10A is preferably 2.20 or more, and more preferably 2.25 or more.

[0035] The reinforcing cloth 13 is composed of woven fabric, knitted fabric, non-woven fabric, etc. From the viewpoint of increasing the kurtosis Sku of the surface roughness of the surface of the reinforcing cloth 13 and thus suppressing the running noise to a small level, the reinforcing cloth 13 is preferably composed of woven fabric. The woven fabric constituting the reinforcing cloth 13 is woven from warp yarns and weft yarns. From the same viewpoint, the woven fabric constituting the reinforcing cloth 13 is preferably arranged such that the crossing angle of the warp yarns and the weft yarns is 90°, and the extending direction of the warp yarns is the belt width direction and the extending direction of the weft yarns is the belt length direction. It should be noted that the crossing angle of the warp yarns and the weft yarns may not be 90°. The extending direction of the warp yarns may be inclined with respect to the belt width direction. The extending direction of the weft yarns may be inclined with respect to the belt length direction.

[0036] Hereinafter, a case where the reinforcing cloth 13 is composed of woven fabric and the warp yarns and weft yarns with a crossing angle of 90° extend along the belt width direction and the belt length direction respectively will be described.

[0037] In this case, as the fabric structure of the woven fabric constituting the reinforcing cloth 13, for example, plain weave, twill weave, satin weave, their modified weaves, and special weaves can be cited. From the viewpoint of increasing the kurtosis Sku of the surface roughness of the surface of the reinforcing cloth 13 and thus suppressing the running noise to a small level, the fabric structure of the woven fabric constituting the reinforcing cloth 13 is preferably twill weave and satin weave. As the twill weave, for example, the 1 / 3 twill shown in Figure 2A can be cited, Figure 2B the 3 / 1 twill shown in Figure 3A etc. As the satin weave, the five-harness two-over-one satin shown in Figure 3B can be cited, Figure 2A and 2B and Figure 3A and 3BIn the organization chart, the warp threads are black and the weft threads are white.

[0038] Examples of the fiber material forming the warp threads include nylon fiber (aliphatic polyamide fiber), polyester fiber, aramid fiber (aromatic polyamide fiber), cotton, etc. From the viewpoint of increasing the kurtosis Sku of the surface roughness of the reinforcing cloth 13 to suppress the running-away sound to a small level, the fiber material forming the warp threads is preferably nylon fiber, and more preferably nylon 6,6 fiber.

[0039] From the viewpoint of increasing the kurtosis Sku of the surface roughness of the reinforcing cloth 13 to suppress the running-away sound to a small level, the fineness of the warp threads is preferably 30 dtex or more and 300 dtex or less, and more preferably 90 dtex or more and 170 dtex or less. From the same viewpoint, the number of warp threads per 5 cm width is preferably 200 or more and 500 or less, more preferably 220 or more and 275 or less, and further preferably 240 or more and 260 or less. From the same viewpoint, the total fineness of the warp threads per 5 cm width is preferably 15000 dtex or more and 60000 dtex or less, more preferably 20000 dtex or more and 30000 dtex or less, and further preferably 25000 dtex or more and 29000 dtex or less.

[0040] Examples of the fiber material forming the weft threads include nylon fiber (aliphatic polyamide fiber), polyester fiber, aramid fiber (aromatic polyamide fiber), cotton, etc. From the viewpoint of increasing the kurtosis Sku of the surface roughness of the reinforcing cloth 13 to suppress the running-away sound to a small level, the fiber material forming the weft threads is preferably nylon fiber, and more preferably nylon 6,6 fiber. From the same viewpoint, the fiber material forming the weft threads is preferably the same as the fiber material forming the warp threads. Both the fiber material forming the weft threads and the fiber material forming the warp threads are preferably nylon fiber, and more preferably nylon 6,6 fiber.

[0041] The weft threads are arranged to extend along the tape length direction and form the tooth portions 10A, so the weft threads preferably have elasticity. The weft threads are preferably core-spun yarns wound around a core material of false-twist processed yarn or polyurethane elastic yarn.

[0042] From the viewpoint of increasing the kurtosis Sku of the surface roughness of the reinforcing cloth 13 to suppress the running-away sound to a small level, the fineness of the weft threads is preferably 40 dtex or more and 300 dtex or less, and more preferably 150 dtex or more and 160 dtex or less. From the same viewpoint, the ratio of the fineness of the weft threads to the fineness of the warp threads is preferably 0.5 or more and 2 or less, and more preferably 1 or more and 1.5 or less. From the same viewpoint, it is preferable that the fineness of the weft threads is greater than the fineness of the warp threads.

[0043] From the viewpoint of increasing the kurtosis Sku of the surface roughness of the reinforcing fabric 13 to suppress the running noise to a small level, the number of weft yarns per 5 cm width is preferably 120 or more and 350 or less, more preferably 170 or more and 190 or less. From the same viewpoint, the ratio of the number of weft yarns per 5 cm width to the number of warp yarns per 5 cm width is preferably 0.5 or more and 0.9 or less, more preferably 0.6 or more and 0.85 or less, and further preferably 0.65 or more and 0.8 or less. From the same viewpoint, it is preferable that the number of weft yarns per 5 cm width is less than the number of warp yarns per 5 cm width.

[0044] From the viewpoint of increasing the kurtosis Sku of the surface roughness of the reinforcing fabric 13 to suppress the running noise to a small level, the total fineness of the weft yarns per 5 cm width is preferably 15000 dtex or more and 50000 dtex or less, more preferably 20000 dtex or more and 29000 dtex or less, and further preferably 27000 dtex or more and 28000 dtex or less. From the same viewpoint, the ratio of the total fineness of the weft yarns per 5 cm width to the total fineness of the warp yarns per 5 cm width is preferably 0.5 or more and 1.5 or less, more preferably 0.7 or more and 1.2 or less, and further preferably 0.95 or more and 1.1 or less.

[0045] It is preferable to perform an adhesion treatment on the reinforcing fabric 13 for adhesion to the belt main body 11. As the adhesion treatment, RFL treatment, impregnation treatment, and coating treatment can be cited.

[0046] The RFL treatment is a treatment in which the reinforcing fabric 13 is impregnated in an RFL aqueous solution and then heated. The RFL solution is a solution obtained by mixing an initial condensate (RF) of resorcinol (R) and formalin (F) with a rubber latex (L). As the rubber latex (L), for example, vinylpyridine·styrene-butadiene copolymer rubber (VP-SBR) latex, chloroprene rubber (CR) latex, chlorosulfonated polyethylene rubber (CSM) latex, 2,3-dichlorobutadiene polymer rubber (2,3-DCB) latex, nitrile rubber (NBR) latex, etc. can be cited.

[0047] The impregnation treatment is a treatment in which the RFL-treated reinforcing fabric 13 is impregnated in a low-viscosity rubber paste and then dried. The coating treatment is a treatment in which a high-viscosity rubber paste is applied to the surface of the RFL-treated or impregnated reinforcing fabric 13 on the side of the belt body 11 and dried. The rubber paste used in the impregnation treatment or coating treatment is obtained by dissolving an uncrosslinked rubber composition in an organic solvent such as toluene or methyl ethyl ketone. The uncrosslinked rubber composition is, for example, the same rubber composition as the rubber component of the rubber composition forming the belt body 11, or a rubber composition having a chlorinated rubber (such as chloroprene rubber (CR) or chlorosulfonated polyethylene rubber (CSM)) as the rubber component.

[0048] From the viewpoint of increasing the kurtosis Sku of the surface roughness of the reinforcing fabric 13 to suppress the running sound to a small level, it is preferable not to perform the impregnation treatment among the above treatments on the reinforcing fabric 13. It is preferable to perform the RFL treatment and the coating treatment other than the impregnation treatment on the reinforcing fabric 13. Therefore, it is preferable that the RFL coating adhered to the fiber surface by the RFL treatment is exposed on the surface of the reinforcing fabric 13.

[0049] It should be noted that the base treatment may be performed on the reinforcing fabric 13 before the RFL treatment. The base treatment is a treatment in which the untreated reinforcing fabric 13 before the RFL treatment is impregnated in an epoxy solution or an isocyanate solution and then heated.

[0050] Hereinafter, according to Figure 4 and Figures 5A to 5C the manufacturing method of the toothed belt B according to the embodiment will be described. The manufacturing method of the toothed belt B according to the embodiment has a material preparation process, a forming process, a crosslinking process, and a finishing process.

[0051] <Material preparation process>

[0052] The specified rubber component is kneaded, and various rubber additives are added thereto and kneaded, whereby an uncrosslinked rubber composition having a relatively high rubber hardness is obtained. By performing calendering or the like on the obtained uncrosslinked rubber composition, an uncrosslinked rubber composition sheet 11' is produced.

[0053] The contact treatment is performed on the core wire 12. The contact treatment is performed on the reinforcing fabric 13. As described above, at this time, it is preferable not to perform the impregnation treatment but to perform the RFL treatment and the coating treatment. It is preferable to perform the base treatment as needed. After the bonding treatment, the reinforcing fabric 13 is formed into a tubular shape. At this time, the warp yarn is in the axial direction corresponding to the belt width direction, and the weft yarn is in the circumferential direction corresponding to the belt length direction.

[0054] <Forming process>

[0055] Figure 4The belt forming die 20 is shown. The belt forming die 20 is cylindrical and has an outer peripheral surface on which a plurality of tooth portion forming grooves 21 are arranged at intervals in the circumferential direction, and the plurality of tooth portion forming grooves 21 are each formed to extend in a direction inclined with respect to the axial direction.

[0056] As Figure 5A shown, the cylindrical reinforcing cloth 13 is put on the outer peripheral surface of the belt forming die 20, and the core wire 12 is wound around the reinforcing cloth 13 in a spiral shape.

[0057] Then, the uncrosslinked rubber composition sheet 11' is wound thereon, and the uncrosslinked belt blank S' is formed on the belt forming die 20. It should be noted that when using the uncrosslinked rubber composition sheet 11', it is preferable that its texture direction corresponds to the belt length direction.

[0058] <Crosslinking process>

[0059] As Figure 5B shown, the rubber sleeve 22 is put on the uncrosslinked belt blank S' on the belt forming die 20, and then they are arranged in a vulcanizing tank and sealed, and high-temperature and high-pressure steam is filled into the vulcanizing tank and this state is maintained for a specified molding time. By pressing the uncrosslinked belt blank S' against the belt forming die 20 side and heating it in this way, while the uncrosslinked rubber composition sheet 11' flows into each of the plurality of tooth portion forming grooves 21 of the belt forming die 20 while pressing the reinforcing cloth 13 between the core wires 12, crosslinking occurs. At the same time, the core wire 12 and the reinforcing cloth 13 are combined into one body, and finally as Figure 5C shown, it is molded into a cylindrical belt blank S.

[0060] <Finishing process>

[0061] The inside of the vulcanizing tank is depressurized and unsealed, the belt blank S molded between the belt forming die 20 and the rubber sleeve 22 is taken out and demolded, and the toothed belt B according to the embodiment is obtained by cutting the belt blank S into rings with a specified width.

[0062]

Example

[0063] (Toothed belt)

[0064] Toothed belts of the following Examples 1 to 3 and Comparative Examples were produced. The composition of each reinforcing cloth is shown in Table 1.

[0065] <Example 1>

[0066] In the toothed belt of Example 1, a reinforcing cloth is formed of a 3 / 1 twill weave fabric, and the reinforcing cloth is arranged such that the extending direction of the warp yarn is the belt width direction and the extending direction of the weft yarn is the belt length direction. In the 3 / 1 twill weave fabric constituting the reinforcing cloth, the warp yarn is composed of nylon 6,6 fibers with a fineness of 110 dtex. The weft yarn is composed of a false-twisted yarn of nylon 6,6 fibers with a fineness of 156 dtex (78 dtex × 2). The number of warp yarns and weft yarns per 5 cm width are 253 and 178 respectively.

[0067] As the bonding treatment, the reinforcing cloth is subjected to an RFL treatment and a coating treatment in sequence. In the RFL treatment, an RFL aqueous solution containing CSM latex is used. In the coating treatment, a rubber paste obtained by dissolving an uncrosslinked rubber composition having H-NBR as a rubber component in methyl ethyl ketone is used. It should be noted that the reinforcing cloth is not subjected to an impregnation treatment.

[0068] The belt circumference of the toothed belt of Example 1 is 364 mm, the belt width is 22 mm, and the maximum belt thickness is 2.1 mm. The belt body is formed of a rubber composition having EPDM as a rubber component. A glass fiber twisted yarn is used as the core wire.

[0069] <Example 2>

[0070] In the toothed belt of Example 2, a reinforcing cloth is formed of a five-harness twill weave fabric. In the five-harness twill weave fabric constituting the reinforcing cloth, the warp yarn is composed of nylon 6,6 fibers with a fineness of 110 dtex. The weft yarn is composed of a false-twisted yarn of nylon 6,6 fibers with a fineness of 78 dtex. The number of warp yarns and weft yarns per 5 cm width are 270 and 240 respectively. Other configurations are the same as those of Example 1.

[0071] <Example 3>

[0072] In the toothed belt of Example 3, a reinforcing cloth is formed of a 1 / 3 twill weave fabric. In the 1 / 3 twill weave fabric constituting the reinforcing cloth, the warp yarn is composed of nylon 6,6 fibers with a fineness of 110 dtex. The weft yarn is composed of a false-twisted yarn of nylon 6,6 fibers with a fineness of 156 dtex (78 dtex × 2). The number of warp yarns and weft yarns per 5 cm width are 276 and 178 respectively. Other configurations are the same as those of Example 1.

[0073] <Comparative Example>

[0074] In the toothed belt of the comparative example, a reinforcing fabric is formed of a 3 / 1 twill weave fabric. In the 3 / 1 twill weave fabric forming the reinforcing fabric, the warp yarns are made of nylon 6,6 fibers with a fineness of 44 dtex. The weft yarns are made of false-twisted yarns of nylon 6,6 fibers with a fineness of 156 dtex (78 dtex × 2). The number of warp yarns and weft yarns per 5 cm width are 393 and 168, respectively. Other configurations are the same as those in Example 1.

[0075]

Table 1

[0076]

[0077]

[0078] (Test method)

[0079] <Kurtosis Sku of the surface roughness of the surface of the reinforcing fabric of the tooth part>

[0080] For each of the toothed belts of Example 1 to Example 3 and the comparative example, the kurtosis Sku of the surface roughness of the surface of the reinforcing fabric of the tooth part was measured using a contact / non-contact shape measuring device (digital microscope VHX-6000, manufactured by KEYENCE Corporation).

[0081] <Running-away sound>

[0082] Figure 6A and Figure 6B The pulley layout of the running-away test machine 30 for measuring the running-away sound is shown. The running-away test machine 30 includes: a driving pulley 31 having 41 teeth; a driven pulley 32 having 117 teeth, provided on the side of the driving pulley 31 and movable left and right; and a pickup microphone 33. The driven pulley 32 is configured to be able to carry a fixed load (SW) in a direction away from the driving pulley 31 and to be able to carry a rotational torque. The pickup microphone 33 is provided at a position where its center is 30 mm away from the axis center of the driving pulley 31 toward the driven pulley 32 side and 20 mm away from the top surface of the driving pulley 31.

[0083] Each of the toothed belts B of Example 1 to Example 3 and the comparative example was wound between the driving pulley 31 and the driven pulley 32 of the running-away test machine 30. A fixed load (SW) was applied to the driven pulley to generate a belt tension of 100 N in the toothed belt B, and a rotational torque of 7 N·m was applied. The rotational speed of the driving pulley 31 was increased from 200 rpm to 3000 rpm in 10 seconds, and the running-away sound at this time was picked up by the pickup microphone 33 and subjected to order analysis based on FFT (Fast Fourier Transform) to obtain the average sound pressure level.

[0084] (Test results)

[0085] The test results are shown in Table 1. It can be seen therefrom that, compared with the comparative example in which the kurtosis Sku of the surface roughness of the reinforcing cloth of the tooth part is 2.14, the average sound pressure level of Examples 1 to 3 in which the kurtosis Sku of the surface roughness of the reinforcing cloth of the tooth part is 2.15 or more is lower. Therefore, the running noise is smaller.

[0086] -Industrial Applicability-

[0087] The present invention is very useful in the technical field of toothed belts.

[0088] -Symbol Explanation-

[0089] B Toothed belt

[0090] S' Uncrosslinked belt blank

[0091] S Belt blank

[0092] 10A Tooth part

[0093] 10B Tooth bottom part

[0094] 11 Belt body

[0095] 11' Uncrosslinked rubber composition sheet

[0096] 111 Flat belt part

[0097] 112 Tooth part body

[0098] 12 Core wire

[0099] 13 Reinforcing cloth

[0100] 20 Belt forming die

[0101] 21 Tooth part forming groove

[0102] 22 Rubber sleeve

[0103] 30 Running noise test machine

[0104] 31 Driving pulley

[0105] 32 Driven pulley

[0106] 33 Pickup microphone.

Claims

1. A toothed belt, comprising a belt body and a reinforcing cloth, wherein the belt body has a flat belt portion and a plurality of tooth body portions, and the plurality of tooth body portions are integrally provided at intervals with a constant pitch on one surface of the flat belt portion, the reinforcing cloth is provided to cover the surface of the belt body on the side where the plurality of tooth body portions are provided, the plurality of tooth body portions are respectively covered by the reinforcing cloth to form tooth portions, characterized in that: the kurtosis of the surface roughness of the surface of the reinforcing cloth of the tooth portion is 2.15 or more.

2. The toothed belt according to claim 1, characterized in that: the reinforcing cloth is composed of a woven fabric.

3. The toothed belt according to claim 2, characterized in that: the fabric structure of the woven fabric constituting the reinforcing cloth is twill weave or satin weave.

4. The toothed belt according to claim 2 or 3, characterized in that: the woven fabric constituting the reinforcing cloth is arranged such that the crossing angle of the warp yarns and the weft yarns is 90°, and the extending direction of the warp yarns is the belt width direction and the extending direction of the weft yarns is the belt length direction.

5. The toothed belt according to claim 4, characterized in that: the fiber material forming the warp yarns and the weft yarns is nylon 6,6 fiber.

6. The toothed belt according to claim 4 or 5, characterized in that: the fineness of the warp yarns is 30 dtex or more and 300 dtex or less, and the fineness of the weft yarns is 40 dtex or more and 300 dtex or less.

7. The toothed belt according to any one of claims 4 to 6, characterized in that: the ratio of the fineness of the weft yarns to the fineness of the warp yarns is 0.5 or more and 2 or less.

8. The toothed belt according to any one of claims 4 to 7, characterized in that: the fineness of the weft yarns is greater than the fineness of the warp yarns.

9. The toothed belt according to any one of claims 4 to 8, characterized in that: the number of warp yarns per 5 cm width is 200 or more and 500 or less, and the number of weft yarns per 5 cm width is 120 or more and 350 or less.

10. The toothed belt according to any one of claims 4 to 9, characterized in that: the ratio of the number of weft yarns per 5 cm width to the number of warp yarns per 5 cm width is 0.5 or more and 0.9 or less.

11. The toothed belt according to any one of claims 4 to 10, characterized in that: the number of weft yarns per 5 cm width is less than the number of warp yarns per 5 cm width.

12. The toothed belt according to any one of claims 4 to 11, characterized in that: the total fineness of the warp yarns per 5 cm width is 15000 dtex or more and 60000 dtex or less, and the total fineness of the weft yarns per 5 cm width is 15000 dtex or more and 50000 dtex or less.

13. The toothed belt according to any one of claims 4 to 12, characterized in that: The ratio of the total fineness of the weft yarns per 5 cm width to the total fineness of the warp yarns per 5 cm width is 0.5 or more and 1.5 or less.

14. The toothed belt according to any one of claims 1 to 13, characterized in that: The reinforcing cloth has not been subjected to an impregnation treatment, and the impregnation treatment is a treatment of drying after impregnation into a rubber paste.

15. The toothed belt according to any one of claims 1 to 14, characterized in that: The RFL coating film attached to the fiber surface by RFL treatment is exposed on the surface of the reinforcing cloth.

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