toothed belt

Abstract

A toothed belt in which a core wire is embedded, the core wire being a carbon core wire, a core wire diameter of the core wire being 1.30 mm or more and 1.45 mm or less, the carbon core wire being a twisted wire twisted from a carbon filament, the core wire being single twisted, a twist number of the core wire being 30 tpm or more and 50 tpm or less, an occupancy rate of the core wire per unit width of the belt being 80% or more and 95% or less, a belt PLD being 1.25 mm or more and 1.60 mm or less, and a nominal pitch of the belt teeth being 11 mm.

Description

Technical Field

[0001] This invention relates to a toothed belt.

[0002] This application claims priority based on Japanese Patent Application No. 2024-056700, filed on March 29, 2024, and incorporates all the contents described in the said Japanese patent application. Background Technology

[0003] Toothed belts are suitable for applications requiring synchronized rotation and are used in a variety of fields. For example, toothed belts are used as power transmission mechanisms in motorcycles (e.g., Patent Document 1).

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2021-188747 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] Toothed belts used in the rear-wheel drive of electric two-wheeled vehicles are designed for high-load transmission applications. When toothed belts are used in high-load transmission applications, tooth loss or belt breakage is common. Therefore, toothed belts used in high-load transmission applications require a high level of durability.

[0009] Technical means to solve the problem

[0010] This disclosure is made in view of this actual situation, and its purpose is to provide a toothed belt with excellent durability that can also be used in high-load transmission applications.

[0011] One embodiment of the toothed strip of the present invention is a toothed strip with an embedded core wire.

[0012] In the toothed band

[0013] The core wire is a carbon core wire.

[0014] The core wire diameter is 1.30 mm or more and 1.45 mm or less.

[0015] The carbon core wire is a twisted wire made by twisting carbon filaments together.

[0016] The core wires are twisted in a single twist.

[0017] The core wire has a twist count of 30 tpm or more and 50 tpm or less.

[0018] The core wire occupies more than 80% and less than 95% of each unit width of the strip.

[0019] The pitch line differential (PLD) is greater than 1.25 mm and less than 1.60 mm.

[0020] The nominal pitch of the toothed part is 11 mm.

[0021] The effects of the invention

[0022] This invention provides a toothed belt with excellent durability. Attached Figure Description

[0023] [ Figure 1 ] Figure 1 This is a three-dimensional diagram showing an example of a toothed band.

[0024] [ Figure 2 ] Figure 2 yes Figure 1 AA-line cross-section view.

[0025] [ Figure 3 ] Figure 3 yes Figure 1 BB line end face view.

[0026] [ Figure 4 ] Figure 4 This diagram illustrates the manufacturing method of toothed belts.

[0027] [ Figure 5 ] Figure 5 This diagram illustrates the manufacturing method of toothed belts.

[0028] [ Figure 6 ] Figure 6 This diagram illustrates the manufacturing method of toothed belts.

[0029] [ Figure 7 ] Figure 7 This is a diagram showing the pulley layout used in the belt driving test A.

[0030] [ Figure 8 ] Figure 8 This is a diagram showing the pulley layout used in belt driving test B. Detailed Implementation

[0031] A summary of embodiments of the present invention will be provided for description.

[0032] [1] A toothed strip, in which a core wire is embedded, wherein the toothed strip...

[0033] The core wire is a carbon core wire.

[0034] The core wire diameter is 1.30 mm or more and 1.45 mm or less.

[0035] The carbon core wire is a twisted wire made by twisting carbon filaments together.

[0036] The core wires are twisted in a single twist.

[0037] The core wire has a twist count of 30 tpm or more and 50 tpm or less.

[0038] The core wire occupies more than 80% and less than 95% of each unit width of the strip.

[0039] PLD with a diameter of 1.25 mm or more and 1.60 mm or less.

[0040] The nominal pitch of the toothed part is 11 mm.

[0041] [2] In the toothed belt of [1], the number of carbon filaments is preferably 24,000.

[0042] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0043] (toothed band)

[0044] Figure 1 This is a perspective view showing a portion of the toothed band 1 according to an embodiment of the present invention.

[0045] Figure 2 yes Figure 1 AA-line cross-section view.

[0046] Figure 3 yes Figure 1 BB line end face view.

[0047] Figure 1 This represents a portion of toothed belt 1. Toothed belt 1 is an annular meshing transmission belt. Toothed belt 1 is a single-sided toothed belt.

[0048] exist Figure 1 In the diagram, the double arrow X indicates the width direction of the toothed strip 1. The double arrow Y indicates the length direction of the toothed strip 1. The length direction is also the circumferential direction of the toothed strip 1. The double arrow Z indicates the thickness direction of the toothed strip 1. The upper side of each paper surface represents the outer circumference of the toothed strip 1, and the lower side represents the inner circumference.

[0049] The length of the toothed belt 1 (the length of the belt at the belt spacing line) is, for example, more than 225 mm and less than 6000 mm.

[0050] The width Wb of the toothed belt 1 is, for example, 5 mm or more and 120 mm or less.

[0051] The thickness Tb of the toothed belt 1 is, for example, 3.5 mm or more and 9.0 mm or less. The thickness Tb of the toothed belt 1 is the thickness of the thickest part of the toothed belt 1.

[0052] The size of the toothed belt in the embodiments of the present invention is not limited to the range described above.

[0053] The toothed belt 1 has a back 11 and multiple teeth 12.

[0054] The back 11 extends circumferentially along the belt. The back 11 is an annular belt. In a cross-section of the toothed belt 1 perpendicular to the circumferential direction, the cross-sectional shape of the back 11 is rectangular.

[0055] Multiple teeth 12 are disposed on the inner circumferential side of the back 11. The multiple teeth 12 are arranged at equal intervals along the circumference of the belt. Each tooth 12 extends along the width of the belt. The portion of adjacent teeth 12 that clamps each other is the tooth root 24.

[0056] The nominal pitch of the teeth 12 of the toothed belt 1 is 11 mm.

[0057] Here, the term "nominal pitch" refers to the same meaning as used in Japanese Industrial Standard (JIS) B 1857-1, etc. In the embodiment of the present invention, the tooth pitch Pb of the toothed belt 1 ranges from 11 mm ± 0.03 mm.

[0058] For example, the tooth profile of tooth 12 is a circular arc tooth profile.

[0059] By setting the nominal pitch of the teeth 12 to 11 mm, the toothed belt 1 can be suitably used as a power transmission component for motorcycles, including electric motorcycles.

[0060] The reason is that a toothed belt with a nominal pitch of 11 mm is easier to design to be high-strength and less prone to breakage than a toothed belt with a nominal pitch of 8 mm. Compared with a toothed belt with a nominal pitch of 14 mm, the pulley diameter can be reduced, which can easily help to make motorcycles smaller or lighter.

[0061] The toothed belt 1 includes a belt body 2, a core wire 3, and a reinforcing cloth 4.

[0062] The main body 2 is strip-shaped.

[0063] The belt body 2 includes a base 21 and multiple teeth 22.

[0064] The base 21 extends circumferentially along the belt. A core wire 3 is embedded in the base 21. Multiple teeth 22 are disposed on the inner circumferential side of the base 21. The multiple teeth 22 are integral with the base 21. The multiple teeth 22 are arranged at equal intervals circumferentially along the belt. The surface of the teeth 22 is covered with reinforcing fabric 4.

[0065] The main body 2 includes, for example, a rubber composition formed by crosslinking an uncrosslinked rubber composition containing rubber components and rubber compounding agents through heating and pressure (hereinafter also referred to as a crosslinked rubber composition).

[0066] The base 21 and teeth 22 of the main body 2 respectively contain a cross-linked rubber composition.

[0067] exist Figure 1 In the toothed band 1 shown, the base 21 and the teeth 22 contain the same crosslinked rubber composition. The crosslinked rubber composition constituting the base 21 and the crosslinked rubber composition constituting the teeth 22 may also be different.

[0068] Details of the crosslinked rubber composition will be described later.

[0069] The belt body 2 containing the crosslinked rubber composition, for example, the teeth 22, has a JIS A hardness of 84 A or higher and 98 A or lower. In this case, the belt body 2 is less prone to deformation and less likely to experience breakage of the teeth 22 due to cracking.

[0070] The JIS A hardness of the tooth 22 is measured by pressing a rubber durometer perpendicularly against the side of the tooth 22 (the end face of the tooth 22 in the belt width direction) of the belt body 2. A type A durometer as specified in JIS-K6253-3 (2012) is used as the rubber durometer. The ambient temperature during measurement is set to 23°C.

[0071] Core wire 3 is buried in base 21.

[0072] The core wire 3 is configured to have spacing in the width direction and form a spiral.

[0073] The core wire 3 has a diameter of 1.30 mm or more and 1.45 mm or less. In this case, it is suitable to provide a toothed belt with good durability. When the core wire diameter is less than 1.30 mm, the core wire itself has a low modulus of elasticity or breaking strength, which sometimes makes it impossible to ensure the durability of the toothed belt. On the other hand, if the core wire diameter exceeds 1.45 mm, the resistance to bending fatigue decreases, or it becomes difficult to wind onto pulleys with a small diameter.

[0074] In this invention, the core wire diameter is the core wire diameter ΦWT in the thickness direction of the core wire.

[0075] The core wire diameter of core wire 3 is preferably 1.35 mm or more and 1.40 mm or less.

[0076] The core wire diameter ΦWA in the width direction of core wire 3 is preferably 1.30 mm or more and 1.45 mm or less. The core wire diameter ΦWT in the thickness direction can be the same as or different from the core wire diameter ΦWA in the width direction, but the smaller the difference between the two, the better.

[0077] The toothed belt 1 with embedded core wire 3 has a belt PLD of 1.25 mm or more and 1.60 mm or less. In this case, good durability of the toothed belt can be ensured.

[0078] On the other hand, if the PLD deviates from the specified range, missing teeth in the toothed belt are likely to occur at an early stage.

[0079] From the viewpoint that it is less likely to produce missing teeth in the toothed belt, the belt PLD is preferably 1.38 mm or more and 1.60 mm or less.

[0080] The PLD refers to the distance between the pitch line and the bottom surface of the tooth in the toothed band 1.

[0081] The PLD can be adjusted, for example, by changing the core diameter of the core wire 3 or the thickness of the reinforcing cloth 4.

[0082] The carbon core wire is a twisted wire formed by twisting carbon filaments together. The carbon filaments are filaments containing carbon fibers. The twisting of the core wire is a single twist.

[0083] Regarding core wire 3, the twisting of the carbon filaments into a single twist can improve the elastic modulus of the core wire and ensure the good durability of the toothed belt.

[0084] On the other hand, when the carbon core wire is twisted into a stranded twist or a unidirectional twist, the toothed belt using these core wires has poor durability.

[0085] In the toothed belt 1, the core wire 3 can be an S-twisted wire, a Z-twisted wire, or both.

[0086] The core wire 3 is preferably arranged such that, in the width direction, S-twisted core wire 3 and Z-twisted core wire 3 alternate with a gap.

[0087] The core wire has a twist count of 30 turns per meter (tpm) or more and 50 tpm or less. Under these conditions, good durability of the toothed belt can be ensured.

[0088] On the other hand, when the twist count of the core wire is less than 30 tpm, its performance as a core wire cannot be guaranteed. In addition, if the twist count of the core wire exceeds 50 tpm, missing teeth in the toothed belt are likely to occur, reducing the durability of the toothed belt.

[0089] The preferred twist number of the core wire is 35 tpm or more and 45 tpm or less.

[0090] The number of carbon filaments (also known as the filament count) is preferably 24,000 (24K). In this case, it is suitable to provide a toothed belt with good durability.

[0091] Here, the term "24K" refers to the number of carbon filaments, but strictly speaking, it doesn't mean there are actually 24,000 carbon filaments; approximately 24,000 is sufficient. In the carbon fiber industry, carbon fiber containing approximately 24,000 filaments is traded as "24K".

[0092] The carbon filament can be a polyacrylonitrile (PAN) based carbon filament or a pitch-based carbon filament. From the viewpoint of easily improving the durability of toothed belts used in high-load transmission applications, the carbon filament is preferably a PAN based carbon filament.

[0093] The diameter of the carbon filament is, for example, 5 μm or more and 7 μm or less.

[0094] The core wires 3 are configured to extend in parallel with open intervals in the width direction. In appearance, multiple core wires 3 are arranged in the width direction.

[0095] At this point, the core wire 3 occupies more than 80% and less than 95% of the area per unit width of the tape. Under these conditions, a toothed tape with good durability is suitable.

[0096] If the occupancy rate deviates from the specified range, the longitudinal elastic modulus of the belt decreases, making it prone to premature tooth loss.

[0097] The percentage of core wire 3 per unit width of the belt (%) refers to a cross-section cut perpendicularly along the length of the belt, passing through the center of the belt teeth 12. Figure 2 The percentage of "the sum of the core diameters of core wire 3" relative to "band width" in the text.

[0098] The core wire 3 can also be subjected to bonding treatment to improve the adhesion to the tape body 2.

[0099] Examples of such bonding treatments include, for instance, the RFL treatment, which involves immersing the rubber in an aqueous solution of resorcinol formaldehyde latex (RFL) followed by heating, and the rubber mortar treatment, which involves immersing the rubber in mortar followed by drying. Only one of these bonding treatments may be performed, or both may be performed.

[0100] For core wire 3, a substrate treatment may also be performed before the bonding process. Examples of such substrate treatments include, for instance, impregnation in an epoxy solution or isocyanate solution followed by heating.

[0101] In the toothed belt manufacturing method described later, these bonding or substrate treatments are performed before the core wire is wound onto the mold.

[0102] The reinforcing fabric 4 covers the surface of the toothed section 22. The reinforcing fabric 4 forms the inner circumferential surface of the toothed belt 1. The inner circumferential surface of the toothed belt 1 includes the reinforcing fabric 4.

[0103] Reinforcing fabric 4 is a woven fabric.

[0104] Fibers constituting the reinforcing fabric 4 may include, for example, polyamide fibers (nylon fibers), polyester fibers, aromatic polyamide fibers, polyp-phenylenebenzobisoxazole (PBO) fibers, cotton, etc.

[0105] As the reinforcing fabric 4, a fabric made of polyamide fibers is preferred, for example.

[0106] The thickness of the reinforcing fabric 4 is, for example, 0.50 mm or more and 1.00 mm or less.

[0107] The reinforcing fabric 4 is preferably a fabric that has elasticity, such as a fabric obtained by performing a wool-like processing on the weft yarn.

[0108] The reinforcing fabric 4 can also be subjected to bonding treatment to improve the adhesion to the main body 2.

[0109] Examples of the bonding treatments include RFL treatment, which involves immersing the material in an RFL aqueous solution followed by heating; immersion treatment, which involves immersing the material in a low-viscosity rubber paste followed by drying; and coating treatment, which involves applying a high-viscosity rubber paste to the surface of the belt body and then drying it. One or more of these bonding treatments may be performed.

[0110] Alternatively, the reinforcing fabric 4 can be subjected to a substrate treatment involving impregnation in an epoxy solution or isocyanate solution followed by heating, prior to further processing.

[0111] In the toothed belt manufacturing method described later, these bonding or substrate treatments are performed before the reinforcing fabric 4 is wound onto the mold.

[0112] Next, the crosslinked rubber composition constituting the main body 2 will be described.

[0113] As described above, the main body 2 may, for example, comprise a cross-linked rubber composition formed by cross-linking an uncross-linked rubber composition containing rubber components and rubber compounding agents.

[0114] Examples of rubber components include, for instance, hydrogenated nitrile butadiene rubber (HNBR), alloys in which at least one of metal salts of acrylate, metal salts of methacrylate, metal salts of polyacrylate, and metal salts of polymethacrylate are microdispersed in hydrogenated nitrile butadiene rubber (HNBR), ethylene-α-olefin elastomers such as chloroprene rubber (CR) and ethylene propylene diene monomer (EPDM), chlorosulfonated polyethylene rubber, styrene-butadiene rubber, and epichlorohydrin rubber. These can be used alone or in combination of two or more.

[0115] The preferred rubber component is HNBR, an alloy in which at least one of zinc acrylate, zinc methacrylate, zinc polyacrylate and zinc polymethacrylate is microdispersed in HNBR, or EPDM.

[0116] The main body 2 is particularly preferably a crosslinked material comprising an uncrosslinked rubber composition containing hydrogenated nitrile butadiene rubber (HNBR).

[0117] Examples of rubber compounding agents include short fibers, vulcanization accelerators, anti-aging agents, reinforcing materials, plasticizers, co-crosslinking agents, crosslinking agents, processing aids, etc.

[0118] Examples of such short fibers include aramid short fibers, nylon short fibers, and polyester short fibers.

[0119] The preferred aromatic polyamide short fiber is the para-aromatic polyamide short fiber.

[0120] These short fibers can be used in single or multiple ways.

[0121] The length of the short fibers is, for example, more than 0.5 mm and less than 3.5 mm.

[0122] The short fibers have a diameter of, for example, 5 μm or more and 50 μm or less.

[0123] The preferred content of the short fibers is 1 part by mass and 7 parts by mass relative to 100 parts by mass of the rubber component.

[0124] Examples of vulcanization accelerators include metal oxides, metal carbonates, fatty acids and their derivatives. Examples of metal oxides include zinc oxide (zinc white) and magnesium oxide.

[0125] These vulcanization accelerators can be used in single or multiple applications.

[0126] The content of the vulcanization accelerator is, for example, more than 3 parts by mass and less than 20 parts by mass relative to 100 parts by mass of the rubber component.

[0127] Examples of anti-aging agents include benzimidazole-based anti-aging agents, aromatic secondary amine-based anti-aging agents, and amine-ketone-based anti-aging agents. Only one of these anti-aging agents may be used, or two or more may be used in combination.

[0128] The content of the anti-aging agent is, for example, more than 1.5 parts by mass and less than 5.0 parts by mass relative to 100 parts by mass of the rubber component.

[0129] Examples of reinforcing materials include carbon black and silicon dioxide. Carbon black and silicon dioxide may be used together as reinforcing materials.

[0130] Examples of carbon black include channel black, furnace black, thermal black, and acetylene black.

[0131] Examples of furnace blacks include, for example, super abrasion furnace black (SAF), intermediate super abrasion furnace black (ISAF), N-339, high abrasion furnace black (HAF), N-351, medium abrasion furnace black (MAF), fast extruding furnace black (FEF), semi-reinforcing furnace black (SRF), general purpose furnace black (GPF), extra conductive furnace black (ECF), and N-234.

[0132] Examples of thermal black include fine thermal black (FT) and medium thermal black (MT).

[0133] Carbon black can be used in single or multiple forms.

[0134] When using carbon black, its content is, for example, 5 parts by mass and 50 parts by mass relative to 100 parts by mass of the rubber component.

[0135] When silica is used, its content is, for example, 10 parts by mass or more and 30 parts by mass or less relative to 100 parts by mass of the rubber component.

[0136] Examples of plasticizers include dialkyl sebacate, dialkyl phthalate, and dialkyl adipate.

[0137] Examples of dialkyl sebacate include polyether esters and dioctyl sebacate (DOS).

[0138] Examples of dialkyl phthalates include dibutyl phthalate (DBP) and dioctyl phthalate (DOP).

[0139] Examples of dialkyl adipate esters include dioctyl adipate (DOA).

[0140] These plasticizers can be used in single or combined with two or more.

[0141] The content of the plasticizer is, for example, 5 parts by mass and 20 parts by mass relative to 100 parts by mass of the rubber component.

[0142] Examples of co-crosslinking agents include trimethylolpropane trimethacrylate, m-phenylene dimaleimide, zinc dimethacrylate, and triallyl isocyanurate. Only one of these co-crosslinking agents may be used, or two or more may be used in combination.

[0143] The content of the co-crosslinking agent is, for example, 3 parts by mass and 10 parts by mass relative to 100 parts by mass of the rubber component.

[0144] Examples of crosslinking agents include sulfur and organic peroxides. Sulfur and organic peroxides can also be used together. Of course, either one can also be used alone.

[0145] As the crosslinking agent, when sulfur and organic peroxide are used together, the total amount of the crosslinking agent is preferably, for example, 0.1 parts by mass or more and 3 parts by mass or less of sulfur and 1 part by mass or more and 12 parts by mass or less of organic peroxide relative to 100 parts by mass of rubber component.

[0146] Examples of processing aids include stearic acid, polyethylene wax, and metal salts of fatty acids. One or more of these processing aids may be used. The content of the processing aid is, for example, 0.5 parts by mass and 2 parts by mass or less per 100 parts by mass of the rubber component.

[0147] (Manufacturing method of toothed belt)

[0148] Figures 4-6 This is a diagram used to illustrate the manufacturing method of the toothed belt 1. Figures 4-6 The image only shows the mold 5 for forming the belt and a portion of the belt (including the belt material).

[0149] In the manufacture of toothed belt 1, a mold 5 for belt forming is used.

[0150] The mold 5 is cylindrical. An axially extending recess 51 and an axially extending protrusion 52 are provided on the outer periphery of the mold 5. The recess 51 has a cross-sectional shape corresponding to the toothed section 12 and extends axially (towards...). Figure 5 The groove extends in the direction perpendicular to the paper surface. The recesses 51 are spaced apart circumferentially. The protrusions 52 are provided between adjacent recesses 51.

[0151] (1) Prepare materials.

[0152] The rubber components are plasticized, and then mixed with a rubber compounding agent to obtain an uncrosslinked rubber composition. The obtained uncrosslinked rubber composition is shaped to produce an uncrosslinked rubber sheet 23. At this time, the shaping method of the uncrosslinked rubber sheet 23 can be, for example, calendering.

[0153] Prepare core wire 3 and reinforcing cloth 4, and perform bonding treatment or substrate treatment as needed.

[0154] Then, the reinforcing fabric 4 is shaped into a tubular shape.

[0155] (2) such as Figure 4 As shown, firstly, a reinforcing fabric 4, shaped into a cylindrical form, is coated onto the outer peripheral surface of the mold 5.

[0156] Next, the core wire 3 is wound in a spiral shape from the reinforcing fabric 4. At this time, the core wire 3 is preferably wound in a spiral shape with S-twisted core wires and Z-twisted core wires in pairs.

[0157] After winding the core wire 3, the uncrosslinked rubber sheet 23 is then wound. Multiple sheets (in...) Figure 4 Two uncrosslinked rubber sheets 23 are formed in the middle. Thus, an uncrosslinked molded body 13C, in which the reinforcing fabric 4, the core wire 3 and the uncrosslinked rubber sheet 23 are stacked, is formed on the outer periphery of the mold 5.

[0158] When multiple uncrosslinked rubber sheets 23 are wound together, each uncrosslinked rubber sheet may have the same composition or different compositions.

[0159] (3) such as Figure 5As shown, a rubber sleeve 6 is applied to the uncrosslinked molded body 13C on the mold 5. The uncrosslinked molded body 13C covered with the rubber sleeve 6 is placed inside a vulcanizing tank (not shown) along with the mold 5, and the vulcanizing tank is then sealed. High-temperature and high-pressure steam is filled into the vulcanizing tank. This state is maintained for a specified time. Thus, the uncrosslinked molded body 13C is heated while being pressed against the mold 5.

[0160] Uncrosslinked rubber sheet 23 flows within the cavity formed between mold 5 and rubber sleeve 6. Uncrosslinked rubber sheet 23 passes between core wires 3. Uncrosslinked rubber sheet 23 flows into each of the plurality of recesses 51 provided in mold 5 while pressing the reinforcing fabric 4. As it flows within the cavity, uncrosslinked rubber sheet 23 becomes integrated with and crosslinks with the core wires 3 and reinforcing fabric 4. As a result, as... Figure 6 As shown, a cylindrical strip blank 14B is formed.

[0161] (4) The inside of the vulcanizing tank is depressurized to release the seal. The strip blank 14B formed between the mold 5 and the rubber sleeve 6 is demolded. The demolded strip blank 14B is cut into round pieces. By going through this process, toothed strip 1 can also be obtained.

[0162] Example

[0163] The embodiments of the present invention will be described in more detail below through examples, but the embodiments of the present invention are not limited to the following examples.

[0164] Here, multiple toothed belts are manufactured and their performance is evaluated.

[0165] (with raw materials)

[0166] (1) Uncrosslinked rubber composition

[0167] Prepare an uncrosslinked rubber composition with the formulation (parts by weight) shown in Table 1.

[0168] Uncrosslinked rubber compositions are prepared by plasticizing rubber components and then mixing them with rubber compounding agents.

[0169] [Table 1]

[0170]

[0171] In Table 1, HNBR(1) is ZP2010 (manufactured by ZEON Corporation, Japan), and HNBR(2) is ZSC2195CX (manufactured by ZEON Corporation, Japan). Additionally, in Table 1, the aromatic polyamide staple fiber is a para-aromatic polyamide staple fiber with a fiber length of 1 mm, and the organic peroxide is PEROXYMON F40 (manufactured by Nippon Oil Company).

[0172] (2) Core wire

[0173] Carbon core wires (1) to (8) with the structures shown in Table 2 were prepared.

[0174] As carbon filaments used to make carbon core wires (1) to (8), a Toray-manufactured T700SC-12K was prepared and twisted with a specified number of filaments, twisting method and twist number to produce carbon core wires. As carbon core wires, S-twisted core wires and Z-twisted core wires were made.

[0175] [Table 2]

[0176]

[0177] (3) Reinforcing fabric

[0178] The following bonding treatment is applied to fabrics in which the warp and weft threads contain polyamide fibers.

[0179] As a follow-up treatment, a wetting process is performed by immersing the fabric in a low-viscosity rubber paste and then drying it, and a coating process is performed by applying a high-viscosity rubber paste to the side of the fabric that serves as the main body and then drying it.

[0180] Regarding the thickness of the reinforcing fabric, the thickness of the reinforcing fabric during preparation was adjusted so that the thickness of the reinforcing fabric in the finished toothed belt is as shown in Tables 3 and 4.

[0181] [Examples 1-6, Comparative Examples 1-13]

[0182] The toothed belt was manufactured by performing the manufacturing methods described in steps (1) to (4). The obtained toothed belt has S-twisted core wires 3 and Z-twisted core wires 3 alternately arranged at intervals in the belt width direction.

[0183] The structure of the toothed belt is shown in Tables 3 and 4.

[0184] In step (3) of the toothed belt manufacturing method, the vulcanization conditions are set at 170°C for 30 minutes.

[0185] The obtained toothed belt was evaluated through belt driving test A and belt driving test B.

[0186] (Dimensions of the toothed belt)

[0187] Toothed belts of various types, known as H11M, H8M, and H14M, were manufactured. Furthermore, the width of the manufactured toothed belts was 10 mm.

[0188] The toothed belts of H8M and H14M are toothed belts according to JIS B1857-1 (2015). The toothed belt of H11M is a toothed belt with a tooth pitch of 11 mm ± 0.03 mm.

[0189] (evaluate)

[0190] The toothed belts manufactured in the examples and comparative examples were subjected to belt driving tests A and B. The results are shown in Table 3.

[0191] (1) Driving test A (missing tooth test)

[0192] The test is an evaluation of the durability of the toothed belt with missing teeth.

[0193] Figure 7 This indicates the pulley layout of the belt driving test machine 90 used in belt driving test A.

[0194] The driving test machine 90 includes a drive pulley 91 and a driven pulley 92 disposed on its left side. The driven pulley 92 is configured to move left and right so as to be able to carry axle loads (SW).

[0195] The belt driving test A is conducted by winding the toothed belt, which is the evaluation object, around each pulley.

[0196] In belt driving test A, when the toothed belt being evaluated was a toothed belt with a tooth pitch of 11 mm (a toothed belt other than Comparative Example 6 and Comparative Example 7), a toothed pulley with 28 teeth and a tooth groove shape of H11M was used as the driving pulley 91, and a toothed pulley with 62 teeth and a tooth groove shape of H11M was used as the driven pulley 92.

[0197] In addition, when the toothed belt being evaluated is a toothed belt with a tooth pitch of 8 mm (Comparative Example 6), a toothed pulley with 38 teeth and a tooth groove shape of H8M is used as the drive pulley 91, and a toothed pulley with 84 teeth and a tooth groove shape of H8M is used as the driven pulley 92.

[0198] Furthermore, when the toothed belt being evaluated is a toothed belt with a tooth pitch of 14 mm (Comparative Example 7), a toothed pulley with 22 teeth and a tooth groove shape of H14M is used as the driving pulley 91, and a toothed pulley with 48 teeth and a tooth groove shape of H14M is used as the driven pulley 92.

[0199] The driving test A was conducted under the following conditions: a driving side speed of 5000 rpm, a driven side speed of 2258 rpm, a driven side load of 150 N·m, an axle load (SW) of 618 N, and an ambient temperature of 60 °C.

[0200] In addition, the shaft load (SW) is set based on the shaft load of the force sensor. During setting, after setting the target tension, the pulley is manually rotated and the belt is wound 3 times, then the setting is repeated according to the target tension.

[0201] In the driving test, the shortest time required for tooth loss, separation (peeling between the belt body and the core wire), and cut was measured. The results are shown in Tables 3 and 4.

[0202] (2) Driving test B (bending fatigue test)

[0203] The test described is an evaluation of the bending fatigue resistance of the toothed belt.

[0204] Figure 8 This indicates the pulley layout of the belt driving test machine 100 used in belt driving test B.

[0205] The belt-driven testing machine 100 includes a drive pulley 101 and three driven pulleys 102. Driven pulley 102a is positioned diagonally above and to the right of the drive pulley 101. Driven pulley 102b is positioned diagonally above and to the left of driven pulley 102a, and above the drive pulley 101. Driven pulley 102c is positioned diagonally below and to the left of driven pulley 102b, and to the left of driven pulley 102a.

[0206] Driven pulley 102b is configured to move up and down to apply axle load (DW). In the belt travel test machine 100, drive pulley 101 and three driven pulleys 102 are arranged such that the contact angle between the toothed belt and drive pulley 101 is 120 degrees.

[0207] The belt driving test B is conducted by winding the toothed belt, which is the evaluation object, around each pulley.

[0208] In belt driving test B, when the toothed belt being evaluated was a toothed belt with a tooth pitch of 11 mm (toothed belts other than those in Comparative Examples 6 and 7), the drive pulley 101 and the driven pulley 102 were both toothed belts with 19 teeth, a tooth groove shape of H11M, and a pitch diameter of 66.5 mm.

[0209] In addition, when the toothed belt being evaluated is a toothed belt with a tooth pitch of 8 mm (Comparative Example 6), a toothed pulley with 26 teeth, a tooth groove shape of H8M, and a pitch diameter of 66.2 mm is used as the drive pulley 101 and the driven pulley 102.

[0210] Furthermore, when the toothed belt being evaluated is a toothed belt with a tooth pitch of 14 mm (Comparative Example 7), a toothed pulley with 15 teeth, a tooth groove shape of H14M, and a pitch diameter of 66.8 mm is used as the drive pulley 101 and the driven pulley 102.

[0211] In belt travel test B, the toothed belt to be evaluated is wound around the drive pulley 101 and three driven pulleys 102 of the belt travel test machine 100. A shaft load (DW) of 392 N is applied upward to the driven pulleys 102b to apply belt tension. The drive pulley 101 is rotated at a speed of 5500 times per minute at room temperature to perform belt travel. Furthermore, the belt travel is stopped periodically to check whether the core wire has been cut, and the number of times the toothed belt rotates around the four pulleys before the core wire is cut (belt cycles) is measured.

[0212] In driving test B, the test results were graded according to the following criteria. The results are shown in Tables 3 and 4.

[0213] A: Even if the number of cycles exceeds 5×10 7 The secondary core wire was not cut off either.

[0214] B: with 1×10 7 More than 5 × 10 7 Cut the core wire with fewer than one cycle.

[0215] C: less than 1×10 7 The core wire with the cycle number is cut.

[0216] [Table 3]

[0217]

[0218] [Table 4]

[0219]

[0220] As shown in Tables 3 and 4, the toothed belt of the embodiments of the present invention has good durability.

[0221] The embodiments disclosed herein should be considered illustrative in all respects and not restrictive. The scope of the invention is defined by the claims and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0222] Explanation of icon numbers

[0223] 1: Toothed belt

[0224] 2: With main body

[0225] 3: Core wire

[0226] 4: Reinforcing fabric

[0227] 5: Mold

[0228] 6: Rubber sleeve

[0229] 11: Back

[0230] 12: Toothed

[0231] 13C: Uncrosslinked molded body

[0232] 14B: Strip billet

[0233] 21: Base

[0234] 22: Teeth

[0235] 23: Uncrosslinked rubber sheet

[0236] 51: Concave

[0237] 52: convex part

[0238] 90, 100: Equipped with a driving test machine

[0239] 91, 101: Drive pulley

[0240] 92, 102: Driven pulley

Claims

1. A toothed strip, in which a core wire is embedded, wherein the toothed strip, The core wire is a carbon core wire. The core wire diameter is 1.30 mm or more and 1.45 mm or less. The carbon core wire is a twisted wire made by twisting carbon filaments together. The core wires are twisted in a single twist. The core wire has a twist count of 30 tpm or more and 50 tpm or less. The core wire occupies more than 80% and less than 95% of each unit width of the strip. The pitch difference is greater than 1.25 mm and less than 1.60 mm. The nominal pitch of the toothed part is 11 mm.

2. The toothed belt according to claim 1, wherein, The number of carbon filaments is 24,000.

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