Combined V-belt, method for manufacturing the same, and belt transmission mechanism

Abstract

To provide a wrapped coupling V-belt capable of reducing lateral vibration (or twisting) of a coupling V-belt and improving durability with respect to breakage or ring cut of the belt by reducing a difference of extensions of V-belts traveling in parallel.SOLUTION: A coupling V-belt 1 including a plurality of wrapped V-belt parts V disposed in parallel in a belt width direction and a tie band T for connecting the wrapped V-belt part is formed from a V-belt main body 5 and a cover cloth 6 which covers at least a side face of the V-belt main body 5, and the tie band T includes a core wire 3a. The tie band T may also include an adhesive rubber layer 3 including the core wire 3a. The tie band T may also include a first rubber layer 2, which is formed on an outer peripheral side of the adhesive rubber layer 3, and a second rubber layer 4 which is formed between the adhesive rubber layer 3 and the wrapped V-belt part V. The wrapped V-belt part V may also include a third rubber layer 5a, which is formed on an outer peripheral side of the belt, and a fourth rubber layer 5a having a lower rubber hardness.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a coupled V-belt, a method for manufacturing the same, and a belt transmission mechanism for using multiple wrapped V-belts simultaneously wrapped around pulleys or the like in high-load, long-span (long-distance between shafts) layouts such as large-scale agricultural machinery. [Background technology]

[0002] Friction transmission belts such as V-belts, V-ribbed belts, and flat belts are known as power transmission belts. V-belts include raw-edge type (raw-edge V-belts), in which the friction transmission surface is an exposed rubber layer, and wrapped type (wrapped V-belts), in which the friction transmission surface (V-shaped side) is covered with an outer sheath. These V-belts are widely used in general industrial machinery and agricultural machinery.

[0003] V-belts are typically used individually when they can transmit power on their own. However, in high-load environments requiring massive power transmission, such as large-scale agricultural machinery used on large farms in Europe and the United States, where multiple shafts repeatedly rotate in both forward and reverse directions, it becomes necessary to use multiple V-belts simultaneously. In other words, multiple V-belts must be wrapped around the pulleys of the belt drive mechanism in parallel (multiple belts) and rotated.

[0004] However, when multiple V-belts are used, tension differences may occur between the parallel V-belts, potentially impairing stable power transmission. Furthermore, contact between adjacent V-belts may cause the inner and outer circumferences of the belts to reverse, leading to overturning. Additionally, in large-scale agricultural machinery in Europe and the United States, the distance between the axes of the pulleys around which the V-belts are wound is very long, making the V-belts prone to significant vibration during operation. Moreover, if the lengths of the multiple belts are uneven, vibration may occur.

[0005] Therefore, in environments where multiple V-belts are driven in parallel, a combined belt (combined V-belt) is used, which is composed of multiple annular V-belt sections having the same or corresponding configuration as a V-belt, connected in the belt width direction. This combined belt is constructed as a V-belt in which the above-mentioned belt sections are arranged in parallel and connected by tie bands (connecting members such as fabric).

[0006] Regarding coupled V-belts, various tie bands have been disclosed and proposed, for example, in the following literature.

[0007] Japanese Patent Publication No. 47-34432 (Patent Document 1) discloses a tie band that is a woven fabric layer formed from one woven fabric or two or more woven fabric layers.

[0008] Japanese Utility Model Publication No. 55-45082 (Patent Document 2) discloses a tie band in which two layers of rubber-coated suda record are cross-laminated with an intermediate rubber layer in between.

[0009] Japanese Utility Model Publication No. 55-181050 (Patent Document 3) discloses a tie band consisting of one to multiple layers of rubber mixed with short fibers.

[0010] Japanese Patent Publication No. 55-135244 (Patent Document 4) discloses elastic canvas with rubber as a tie band.

[0011] Japanese Patent Publication No. 03-033536 (Patent Document 5) discloses a tie band in which an adhesive rubber layer and a rubber-coated suda record are laminated.

[0012] Japanese Patent Publication No. 04-351350 (Patent Document 6) discloses a tie band portion with a rectangular cross-section made solely of rubber, and the power transmission coupling V-belt including this tie band portion is covered with a single outer canvas covering over its entire outer circumference, including the tie band portion.

[0013] Japanese Patent Application Laid-Open No. 2020-003061 (Patent Document 7) discloses a woven fabric in which a rubber composition is printed into the texture as a tie band.

[0014] Japanese Patent Application Laid-Open No. 2022-085864 (Patent Document 8) discloses a connecting reinforcing layer formed of a rubber composition containing a fiber structure as a tie band.

Prior Art Documents

Patent Documents

[0015]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Patent Document 7

Patent Document 8

Summary of the Invention

Problems to be Solved by the Invention

[0016] In the joined V-belts of Patent Documents 1 to 8, since the V-belts can be connected and run in a state where a plurality of them are arranged in parallel, even if a tension difference occurs between the plurality of V-belt portions arranged in parallel during running, the vibration and overturning of the V-belt portions can be suppressed to some extent. However, depending on the use environment, the suppression may be insufficient. In particular, if a difference in elongation occurs in the V-belt portions running in parallel, lateral vibration (or twisting) of the V-belt occurs, and as a result, if the V-belt portion rides onto the pulley, it may lead to belt breakage or belt disconnection.

[0017] Therefore, the object of the present invention is to provide a coupled V-belt, a method for manufacturing the same, and a belt transmission mechanism that can reduce lateral sway (or twisting) of the coupled V-belt by reducing the difference in elongation of the wrapped V-belt sections running in parallel.

[0018] Another object of the present invention is to provide a coupled V-belt, a method for manufacturing the same, and a belt transmission mechanism that can reduce the difference in elongation of the wrapped V-belt sections running in parallel, thereby reducing lateral runout (or twisting) of the coupled V-belt and improving its durability against breakage and ring breakage.

[0019] Hereafter, the bonded V-belt of the present invention will also be referred to as a wrapped bonded V-belt. [Means for solving the problem]

[0020] As a result of diligent research to achieve the above objectives, the inventors discovered that by arranging the core wires of the wrapped V-belt in a tie band, the difference in elongation of the parallel running V-belt sections can be reduced, thereby reducing lateral runout (or twisting) of the connected V-belt, and thus completed the present invention.

[0021] In other words, the present invention includes the following embodiments.

[0022] Embodiment [1]: A combined V-belt comprising a plurality of wrapped V-belt sections arranged in the belt width direction and tie bands for connecting these wrapped V-belt sections, The wrapped V-belt portion is formed from a V-belt body and a cover cloth that covers at least the sides of the V-belt body, A bonded V-belt in which the tie band includes the core wire.

[0023] Embodiment [2]: The bonded V-belt of Embodiment [1], wherein the tie band includes an adhesive rubber layer containing the core wire.

[0024] Embodiment [3]: A bonded V-belt according to Embodiment [1] or Embodiment [2], wherein the tie band comprises a first rubber layer formed on the outer circumference of the adhesive rubber layer and a second rubber layer formed between the adhesive rubber layer and the wrapped V-belt portion.

[0025] Embodiment [4]: ​​A bonded V-belt according to any of Embodiments [1] to [3], wherein the V-belt body comprises a third rubber layer formed on the outer circumference of the belt and a fourth rubber layer having a lower rubber hardness Hs (Type A) than the third rubber layer.

[0026] Embodiment [5]: The bonded V-belt of Embodiment [4], wherein a reinforcing layer containing a fibrous structure is interposed between the third rubber layer and the fourth rubber layer.

[0027] Embodiment [6]: A coupled V-belt according to any of Embodiments [1] to [5], wherein the cover cloth does not cover the outer circumferential surface of the V-belt body.

[0028] Embodiment [7]: A bonded V-belt according to any of Embodiments [1] to [6], wherein the average thickness of the wrapped V-belt portion is 60 to 90% of the average thickness of the entire bonded V-belt.

[0029] Embodiment [8]: A coupled V-belt according to any of Embodiments [1] to [7], wherein the belt length is 3000 mm or more.

[0030] Embodiment [9]: A method for manufacturing a bonded V-belt according to any embodiment [1] to [8], comprising a wrapped V-belt precursor manufacturing step of covering a V-belt body precursor with a cover cloth, and a bonding step of bonding a plurality of wrapped V-belt precursors obtained in the above step with tie band precursors including a core wire.

[0031] Embodiment

[10] : A belt transmission mechanism comprising a coupled V-belt according to any of the embodiments [1] to [8] and a pulley.

[0032] Embodiment

[11] : The belt transmission mechanism of Embodiment

[10] used in agricultural machinery.

[0033] In this application, the numerical range represented by "A~B" means "A or greater and B or less," and is used to include the values ​​A and B at both ends of that range. [Effects of the Invention]

[0034] In this invention, since the core wires of the wrapped V-belt are arranged in the tie band, the difference in elongation of the parallel running V-belt sections can be reduced, thereby reducing lateral movement (or twisting) of the connected V-belt. Furthermore, the durability against belt breakage and ring breakage can also be improved. [Brief explanation of the drawing]

[0035] [Figure 1] Figure 1 is a schematic partial cross-sectional perspective view showing an example of the wrapped V-belt of the present invention. [Figure 2] Figure 2 is a schematic cross-sectional view showing a conventional coupled V-belt. [Figure 3] Figure 3 is a schematic cross-sectional view comparing the wrapped V-belt (b) and the V-ribbed belt (a) of the present invention. [Figure 4] Figure 4 is a schematic partial cross-sectional perspective view showing another example of the wrapped bonded V-belt of the present invention. [Figure 5] Figure 5 is a schematic diagram illustrating the cutting process in the wrapped V-belt precursor fabrication process. [Figure 6] Figure 6 is a schematic diagram illustrating the skiving and cover winding processes in the wrapped V-belt precursor fabrication process. [Figure 7] Figure 7 is a schematic overall diagram showing the coupling process. [Figure 8] Figure 8 is a schematic cross-sectional view showing the state in which the wrapped V-belt precursor is fitted into the press mold during the coupling process. [Figure 9] Figure 9 is a schematic cross-sectional view showing the state in which the sheet for the second rubber layer and the sheet for the adhesive rubber layer on the inner circumference are wrapped around the wrapped V-belt precursor during the coupling process. [Figure 10]Figure 10 is a schematic cross-sectional view showing the state in which the core wire is wrapped around the adhesive rubber layer sheet on the inner circumference side of Figure 9 during the coupling process. [Figure 11] Figure 11 is a schematic cross-sectional view showing the state in which the outer adhesive rubber layer sheet and the first rubber layer sheet are wrapped around the core wire shown in Figure 10 during the joining process. [Figure 12] Figure 12 is a schematic cross-sectional view illustrating the crosslinking process of a wrapped bond V-belt precursor. [Figure 13] Figure 13 is a schematic cross-sectional view illustrating the process of severing a cross-linked wrapped bond V-belt precursor. [Figure 14] Figure 14 shows the multi-axis layout used in the durability test of the embodiment. [Figure 15] Figure 15 shows the biaxial layout and method for measuring the amount of lateral runout in the lateral runout test of the embodiment. [Figure 16] Figure 16 is a graph showing data on the lateral sway of a conventional wrapped V-belt. [Figure 17] Figure 17 is a graph showing the change in amplitude over one rotation of an example of a wrapped V-belt measured in Figure 16. [Modes for carrying out the invention]

[0036] <Wrapped V-belt> The coupled V-belt (wrapped coupled V-belt) of the present invention will be described in detail below, with reference to the attached drawings as necessary. In the following description, the same reference numeral may be used for elements (or members) that are identical or have common functions.

[0037] Figure 1 is a schematic partial cross-sectional perspective view showing an example of a bonded V-belt of the present invention. As shown in Figure 1, this bonded V-belt 1 comprises three wrapped V-belt sections V arranged at intervals and parallel to each other in the belt width direction (direction B in Figure 1). The outer circumferential surfaces of these three wrapped V-belt sections V are connected by tie bands (connecting members) T that include a core wire 3a extending in the belt length direction (circumferential direction, direction A in Figure 1).

[0038] The tie band T is formed of an adhesive rubber layer 3 including the core wire 3a, a first rubber layer 2 laminated on the outer circumference side of the adhesive rubber layer 3, and a second rubber layer 4 interposed between the adhesive rubber layer 3 and the wrapped V belt portion V.

[0039] The wrapped V-belt portion V has a structure in which the inner and side surfaces of the V-belt body 5, which consists of a third rubber layer 5a formed on the outer circumference of the belt and a fourth rubber layer 5b laminated on the inner surface of the third rubber layer 5a and having a lower rubber hardness Hs (Type A) than the third rubber layer 5a, are covered with a cover cloth 6.

[0040] [Differences from conventional coupled V-belts] As described above, the bonded V-belt of the present invention is characterized by including a core wire in the tie band. In contrast, as shown in the schematic cross-sectional view in Figure 2, the conventional bonded V-belt 50 has three wrapped V-belt sections 52 connected by tie bands 51 made of fabric or the like on each outer surface. Furthermore, in the conventional bonded V-belt 50, each wrapped V-belt section 52 has a structure in which the entire surface of the wrapped V-belt section 52, which is formed by an expandable rubber layer 53 formed on the outer surface of the belt, an adhesive rubber layer 54 laminated on the inner surface of the expandable rubber layer 53, and a compression rubber layer 55 laminated on the inner surface of the adhesive rubber layer 54, is covered with an outer covering fabric 56.

[0041] Thus, in conventional bonded V-belts, the tie band is formed of fabric or the like, and the core wire is embedded in the wrapped V-belt section, whereas in the bonded V-belt of the present invention, the core wire is embedded in the tie band, which is a significant structural difference. In conventional bonded V-belts, if the core layer (adhesive rubber layer) containing the core wire and the core wire are arranged in each V-belt section, variations in the arrangement of the core wire will occur in each V-belt section. This is presumed to be because even if the arrangement is the same in the design (drawing), variations occur in manufacturing during actual spinning (the arrangement does not match the drawing). In particular, with long belts, the arrangement varies from part to part along the length of a single V-belt section, so the effect is significant. Furthermore, in the field of power transmission belts, the elasticity of a belt is expressed as an indicator of its stretchability, using "elongation rate" or "modulus." This "modulus" is governed by the modulus of the arranged core fibers and is determined by adjusting the fiber type and arrangement density (number of fibers per width). Therefore, the arrangement of the core fibers also affects the belt's elongation. Thus, if there is variation in the arrangement of the core fibers in the length direction of one V-belt section, and also variation among the parallel V-belt sections, a large difference in belt elongation will occur between V-belt sections, which can be presumed to cause lateral sway (or twisting) of the connected V-belts.

[0042] In contrast, the present invention arranges the core wires (particularly the core wires embedded within the adhesive rubber layer) inside the tie band rather than in each V-belt section, resulting in a relatively uniform arrangement of the core wires within the bonded V-belt (such as their position in the thickness direction and the spacing between them). With such an arrangement, the core wires can be arranged using only one spinning unit during manufacturing, thus reducing variations between spinning units.

[0043] Furthermore, while conventional wrapped V-belts mainly consist of belts where the entire outer surface of the V-belt portion is covered with a cover cloth, in the present invention, the outer surface of the V-belt portion is not covered with a cover cloth. Therefore, in the bonded V-belt of the present invention, the third rubber layer is exposed on the outer surface of the V-belt portion, which improves adhesion with the second rubber layer of the tie band.

[0044] [Differences from V-ribbed belts] V-ribbed belts are widely used as belts to drive auxiliary equipment mounted on the engines of ordinary automobiles. As shown in Figure 3(a), a V-ribbed belt has a structure having multiple rib portions 61 on its inner circumference, and these rib portions 61 are formed of a compression rubber layer 64, on the outer circumference of this compression rubber layer 64 an adhesive rubber layer 63 containing a core wire 63a is laminated, and further on the outer circumference of this adhesive rubber layer 63 an expandable rubber layer 62 is laminated. Since the rib portions 61 of the V-ribbed belt 60 are formed only of rubber layers, the fact that the core wire is not embedded in the rib portions is common to both the wrapped-bonded V-belt and the V-ribbed belt of the present invention.

[0045] However, V-ribbed belts are used in environments where high flexibility is crucial, as they operate in a layout that follows the structure of an automobile engine, requiring repeated forward and reverse bending in confined spaces. Therefore, the layout of V-ribbed belts is characterized by relatively short belt lengths, thin belt thicknesses, and smaller required transmission capacity.

[0046] In contrast, the wrapped V-belt of the present invention is a belt for use in belt drive mechanisms of large-scale agricultural machinery used on large farms in Europe and the United States. Depending on the scale of the agricultural machinery, the belt length is long, and it is used in a running layout with a very long distance between the axes (span length) of the pulleys around which the belt is wrapped. Furthermore, because a high transmission capacity is required, a large surface area for friction transmission is necessary.

[0047] Due to these differences in application and running layout, the belt length of a V-ribbed belt is a maximum of 3,000 mm, while that of a wrapped V-belt can reach approximately 10,000 mm. Because wrapped V-belts are so long and the distance between the pulleys is very long, the lateral runout (or twisting) caused by the difference in elongation of the parallel running V-belt sections, which is the problem addressed in this invention, occurs significantly. In contrast, V-ribbed belts, which are shorter and have shorter span lengths, do not experience the problems described in this invention.

[0048] In this invention, as a means of solving the problems specific to wrapped V-belts used in such large-scale agricultural machinery, the dimensions of the wrapped V-belt are designed in a way that is unique to wrapped V-belts (which cannot be conceived from V-ribbed belts), and therefore the two belts have significant differences in shape and structure. For example, Figure 3 shows the sizes of a V-ribbed belt and a wrapped V-belt. In Figure 3(b) relating to the wrapped V-belt, the pitch between adjacent wrapped V-belt sections V is shown as the rib pitch, a represents the thickness of the tie band T, and b represents the thickness of the wrapped V-belt section. On the other hand, in Figure 3(a) relating to the V-ribbed belt, b represents the thickness of the rib section corresponding to the thickness of the wrapped V-belt section, and a represents the thickness obtained by subtracting the thickness of the rib section from the total thickness.

[0049] As is clear from the comparison between Figure 3(a) and Figure 3(b), the wrapped V-belt and the V-ribbed belt differ in the ratio of the rib portion to the belt thickness (b / total thickness), their external shape is different, and their sizes also differ significantly.

[0050] Table 1 shows a comparison of these differences in belt shape between typical V-ribbed belt shapes (H, J, K, L) and typical wrapped V-belt shapes [HA, HB, HC, which are the ASABE (American Society of Agricultural and Biological Engineers) standards].

[0051] [Table 1]

[0052] As shown in Table 1, the differences between the two belts are as follows:

[0053] Wrapped V-belts are generally larger than V-ribbed belts (they have a larger overall thickness and a larger rib pitch).

[0054] As mentioned above, and as shown in Figure 3, the ratio of rib height b to total thickness (b / total thickness) is higher for wrapped V-belts than for V-ribbed belts, accounting for approximately 80% in wrapped V-belts. In other words, for wrapped V-belts, a is set to 2-5 mm and b to 8-15 mm in Figure 3, and "b / total thickness" is set to 60-90%, whereas for V-ribbed belts it is less than 60%.

[0055] Since the rib height b is a design parameter that determines the area of ​​the friction transmission surface, the magnitude of the rib height b determines the transmission capacity of a unit rib (unit V-belt section). Wrapped V-belts have a larger dimension of b and a larger proportion of the total thickness compared to V-ribbed belts, allowing them to be used under high load conditions that cannot be achieved with V-ribbed belts, and providing a higher transmission capacity.

[0056] In reality, the load on a transmission belt for auxiliary drive systems in automobile engines is approximately 1.5 kW per rib, so V-ribbed belts are designed to withstand this level of load. On the other hand, the load conditions for belt transmission mechanisms in large-scale agricultural machinery are approximately 25 kW per rib, so wrapped V-belts need to be designed to withstand this level of load. If a V-ribbed belt were used under the load conditions of a standard V-belt, the friction transmission surface area would be too small to withstand the severe load, causing it to slip out and fail to transmit power.

[0057] [Tie band (connecting member)] In the bonded V-belt of the present invention, the tie band (bonding member) may include a core wire, but it may also be a tie band in which the core wire is embedded in a rubber layer formed of a crosslinked rubber composition. From the viewpoint of improving durability, a tie band is preferred in which a first rubber layer, an adhesive rubber layer containing a core wire, and a second rubber layer are sequentially laminated from the outer circumference.

[0058] (Core wire) The core wires are not particularly limited, but are usually twisted cords arranged at predetermined intervals in the belt width direction. The core wires may be arranged extending in the longitudinal direction of the belt, or in parallel at a predetermined pitch parallel to the longitudinal direction of the belt, but from the viewpoint of productivity, they are usually arranged spirally in parallel at a predetermined pitch approximately parallel to the longitudinal direction of the belt. When the core wires are arranged spirally, the angle of the core wires with respect to the longitudinal direction of the belt may be, for example, 5° or less, and from the viewpoint of belt running performance, it is preferable that it be as close to 0° as possible. In addition, the pitch or spacing (especially the spinning pitch of the core wires), which is the distance between the centers of adjacent core bodies, is preferably set in the range of 1 to 3.6 mm, more preferably in the range of 1.2 to 3 mm, and even more preferably in the range of 1.4 to 2.4 mm.

[0059] The core wire only needs to be in contact with the crosslinked rubber composition that constitutes the adhesive rubber layer. For example, a part of it may be embedded in the crosslinked rubber composition. However, from the viewpoint of improving durability, a configuration in which the core wire is not exposed on the surface of the adhesive rubber layer (a configuration in which the entire core wire is completely embedded in the adhesive rubber layer) is preferred.

[0060] The fibers that make up the core wire include, for example, polyolefin fibers (e.g., polyethylene fibers, polypropylene fibers, etc.), polyamide fibers [e.g., aliphatic polyamide fibers such as polyamide 6 fibers, polyamide 66 fibers, polyamide 46 fibers (nylon fibers), aramid fibers, etc.], and polyalkylene arylate fibers [e.g., polyethylene terephthalate (PET) fibers, polytrimethylene terephthalate (PTT) fibers, polybutylene terephthalate (PBT) fibers, polyethylene naphthalate (PEN) fibers, etc.]. 2-4 Alkilen C 8-14Examples include synthetic fibers such as arylate fibers, vinyl alcohol fibers (polyvinyl alcohol fibers, ethylene-vinyl alcohol copolymer fibers, vinylon fibers, etc.), and poly(p-phenylenebenzobisoxazole) (PBO) fibers; cellulose fibers (cellulose fibers such as cotton and linen, and cellulose derivative fibers, etc.); natural or semi-synthetic fibers such as wool; and inorganic fibers such as carbon fibers. These fibers can be used individually or in combination of two or more types.

[0061] Among the aforementioned fibers, ethylene terephthalate, ethylene-2,6-naphthalate, and other C fibers are selected based on their high modulus. 2-4 Alkylene-C 8-14 Synthetic fibers such as polyester fibers (polyalkylene arylate fibers) and polyamide fibers (such as aramid fibers), which have arylate as their main constituent unit, and inorganic fibers such as carbon fibers are commonly used. Polyester fibers (especially polyethylene terephthalate fibers and polyethylene naphthalate fibers) and polyamide fibers (especially aramid fibers) are preferred, and all aromatic polyamide fibers such as aramid fibers are particularly preferred due to their excellent abrasion resistance. Aramid fibers may be commercially available products such as "Conex®", "Nomex®", "Kevlar®", "Technora", and "Twaron®".

[0062] The fibers constituting the core wire may be in the form of multifilament yarn. The fineness of the multifilament yarn may be, for example, 300 to 10000 dtex (particularly 500 to 5000 dtex). The multifilament yarn may contain, for example, about 100 to 5000 filaments, preferably 500 to 4000 filaments, and more preferably 1000 to 3000 filaments.

[0063] Typically, twisted cords using multifilament yarns (e.g., multi-ply, single-ply, Lang-ply, etc.) can be used as the core wire. The average wire diameter of the core wire (fiber diameter of the twisted cord) may be, for example, 0.5 to 3 mm, preferably 0.6 to 2.5 mm, more preferably 0.7 to 2 mm, and more preferably 1.1 to 2 mm.

[0064] When the core wire is embedded in an adhesive rubber layer, it may be surface-treated to improve adhesion with the crosslinked rubber composition forming the adhesive rubber layer. Methods of surface treatment include treatment with a treatment solution containing conventional surface treatment agents. Examples of surface treatment agents include RFL liquid containing resorcinol (R), formaldehyde (F), and rubber or latex (L) [for example, an RFL liquid in which resorcinol (R) and formaldehyde (F) form a condensate (RF condensate), and the rubber or latex (L) is, for example, vinylpyridine-styrene-butadiene copolymer rubber], epoxy compounds, polyisocyanate compounds, silane coupling agents, and crosslinked rubber compositions (for example, a crosslinked rubber composition containing surface silanol groups and primarily composed of hydrated silicic acid, which is advantageous for increasing chemical bonding with rubber, such as wet-process white carbon). These surface treatment agents may be used individually or in combination of two or more, and the same or different surface treatment agents may be used sequentially multiple times. It is preferable to bond the core wire with at least RFL solution.

[0065] (Adhesive rubber layer) The adhesive rubber layer is formed of a crosslinked rubber composition containing the core wire. The crosslinked rubber composition may be a crosslinked rubber composition (core wire crosslinked rubber composition) containing rubber components that are conventionally used as rubber compositions for wrapped V-belts.

[0066] (A) Rubber component The rubber component (core rubber component) included in the crosslinked rubber composition for core wires can be selected from known vulcanizable or crosslinkable rubbers and / or elastomers. Examples of rubber component (A) include diene rubbers [natural rubber, isoprene rubber, butadiene rubber, chloroprene rubber (CR), styrene-butadiene rubber (SBR), vinylpyridine-styrene-butadiene copolymer rubber, acrylonitrile butadiene rubber (nitrile rubber); hydrogenated versions of the diene rubbers such as hydrogenated nitrile rubber (including a mixed polymer of hydrogenated nitrile rubber and an unsaturated carboxylic acid metal salt)], olefin rubbers [e.g., ethylene-α-olefin rubber (ethylene-α-olefin elastomer), polyoctenylene rubber, ethylene-vinyl acetate copolymer rubber, chlorosulfonated polyethylene rubber, alkylated chlorosulfonated polyethylene rubber], epichlorohydrin rubber, acrylic rubber, silicone rubber, urethane rubber, fluororubber, etc. These rubber components can be used individually or in combination of two or more.

[0067] Of these, ethylene-α-olefin elastomers [ethylene-α-olefin rubbers such as ethylene-propylene copolymer (EPM) and ethylene-propylene-diene terpolymer (EPDM)] and chloroprene rubber are commonly used because the crosslinking agent and crosslinking accelerator diffuse easily. In particular, when the rubber component for the core wire is used in a high-load environment, chloroprene rubber and EPDM are preferred because they have an excellent balance of mechanical strength, weather resistance, heat resistance, cold resistance, oil resistance, and adhesiveness. Furthermore, chloroprene rubber is especially preferred because, in addition to the above properties, it also has excellent abrasion resistance. Chloroprene rubber may be sulfur-modified or non-sulfur-modified.

[0068] When the core wire rubber component contains chloroprene rubber, the proportion of chloroprene rubber in the core wire rubber component may be, for example, 50% by mass or more (particularly around 80-100% by mass), and 100% by mass (chloroprene rubber only) is particularly preferred.

[0069] The proportion of the rubber component for the core wire can be selected from a range of about 10 to 90% by mass in the crosslinked rubber composition for the core wire, preferably 30 to 80% by mass, more preferably 40 to 75% by mass, more preferably 50 to 70% by mass, and most preferably 55 to 65% by mass.

[0070] (B) Filler The cross-linked rubber composition for wire cores may further contain fillers (wire core fillers) in addition to the rubber components for wire cores. Examples of fillers include carbon black, silica (reinforcing silica), clay, calcium carbonate, talc, and mica. These fillers can be used individually or in combination of two or more. Of these fillers, carbon black and silica are preferred, and a combination of carbon black and reinforcing silica is particularly preferred.

[0071] The average particle size (number mean primary particle size) of carbon black is, for example, 5 to 200 nm, preferably 10 to 150 nm, and more preferably 15 to 100 nm. Due to its high reinforcing effect, carbon black may also have a small particle size, with an average particle size of, for example, 5 to 38 nm, preferably 10 to 35 nm, and more preferably 15 to 30 nm. Examples of small-particle carbon black include SAF, ISAF-HM, ISAF-LM, HAF-LS, HAF, and HAF-HS. SAF, ISAF, and HAF are classifications of conventional carbon black, all corresponding to small-particle carbon black known as hard carbon. Specifically, the average particle size of SAF is 19 nm, ISAF is 22 nm, and HAF is 28 nm. These carbon blacks can be used individually or in combination of two or more types.

[0072] In this application, the average particle size of carbon black can be determined, for example, by measuring the particle size of 10 randomly selected primary particles using a transmission electron microscope or the like, and calculating the arithmetic mean.

[0073] Silica includes dry silica, wet silica, and surface-treated silica. Furthermore, silica can be classified by its manufacturing method, such as dry-process white carbon, wet-process white carbon, colloidal silica, precipitated silica, and gel-process silica (silica gel). These silicas can be used individually or in combination of two or more types. Of these, wet-process white carbon, which is mainly composed of hydrated silicic acid, is preferred due to its high surface silanol group content and strong chemical bonding with rubber.

[0074] The average particle size of silica is, for example, 1 to 1000 nm, preferably 3 to 300 nm, more preferably 5 to 100 nm, and more preferably 10 to 50 nm. If the silica particle size is too large, the mechanical properties of the rubber may deteriorate, and if it is too small, it may be difficult to disperse it uniformly.

[0075] Furthermore, silica may be either non-porous or porous, but the specific surface area for nitrogen adsorption by the BET method is, for example, 50 to 400 m². 2 / g, preferably 70-350m 2 / g, more preferably 100-300m 2 / g, more comfortably 150-250m 2 The specific surface area is / g. If the specific surface area is too large, uniform dispersion may become difficult, and if the specific surface area is too small, the mechanical properties of the rubber may deteriorate.

[0076] The proportion of core wire filler is, for example, 1 to 100 parts by mass, preferably 10 to 80 parts by mass, more preferably 30 to 70 parts by mass, and more preferably 40 to 60 parts by mass, per 100 parts by mass of core wire rubber component. If the proportion of core wire filler is too low, the durability of the belt may decrease, and if it is too high, the adhesive strength may decrease.

[0077] When carbon black and reinforcing silica are combined, the proportion of reinforcing silica is, for example, 10 to 200 parts by mass, preferably 30 to 100 parts by mass, and more preferably 50 to 80 parts by mass, per 100 parts by mass of carbon black. If the proportion of reinforcing silica is too low, the adhesive strength may decrease, and if it is too high, the durability of the belt may decrease.

[0078] (C) Other additives The crosslinking rubber composition for core wires may optionally contain other additives such as crosslinking agents (or vulcanizing agents), co-crosslinking agents (crosslinking aids), crosslinking accelerators, crosslinking retarders, metal oxides (calcium oxide, barium oxide, iron oxide, copper oxide, titanium oxide, aluminum oxide, etc.), softeners (oils such as paraffin oil and naphthenic oils), processing agents or processing aids (e.g., fatty acids such as stearic acid, fatty acid metal salts such as metal stearate, fatty acid amides such as stearate amide, waxes, paraffin, etc.), adhesion improvers (e.g., resorcinol-formaldehyde cocondensates (RF condensates), amino resins (condensates of nitrogen-containing cyclic compounds and formaldehyde, e.g., hexamethylolmelamine, hexaalkoxymethylmelamine (hexamethoxymethylmelamine, hexasubtoxicmethylmelamine, etc.)), etc.). The material may contain melamine resin, urea resin such as methylol urea, benzoguanamine resin such as methylolbenzoguanamine resin, and their co-condensates (resorcinol-melamine-formaldehyde co-condensates, etc.), antioxidants (oxidants, thermal aging inhibitors, flexural crack inhibitors, ozone degradation inhibitors, etc.), plasticizers [aliphatic carboxylic acid plasticizers (adipate ester plasticizers, sebacate ester plasticizers, etc.), aromatic carboxylic acid ester plasticizers (phthalate ester plasticizers, trimellitic ester plasticizers, etc.), oxycarboxylic acid ester plasticizers, phosphate ester plasticizers, ether plasticizers, ether ester plasticizers, etc.], colorants, tackifiers, lubricants, coupling agents (silane coupling agents, etc.), stabilizers (ultraviolet absorbers, heat stabilizers, etc.), flame retardants, antistatic agents, etc. Metal oxides may also act as crosslinking agents. Furthermore, in the adhesion improver, the resorcinol-formaldehyde cocondensate and amino resin may be an initial condensate (prepolymer) of resorcinol and / or a nitrogen-containing cyclic compound (such as melamine) and formaldehyde.

[0079] As a crosslinking agent (crosslinking agent for core wires), conventional components can be used depending on the type of rubber component. Examples include metal oxides (magnesium oxide, zinc oxide, lead oxide, etc.), organic peroxides (diasyl peroxide, peroxyester, dialkyl peroxide, etc.), and sulfur-based crosslinking agents. Examples of sulfur-based crosslinking agents include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, and sulfur chloride (sulfur monochloride, sulfur dichloride, etc.). These crosslinking agents can be used alone or in combination of two or more. If the rubber component is chloroprene rubber, metal oxides (magnesium oxide, zinc oxide, etc.) may be used as the crosslinking agent for core wires.

[0080] The proportion of the crosslinking agent for the core wire can be selected from a range of approximately 1 to 20 parts by mass per 100 parts by mass of the rubber component for the core wire, based on solid content, depending on the type of crosslinking agent and rubber component. For example, the proportion of metal oxide as a crosslinking agent is, for example, 1 to 20 parts by mass, preferably 3 to 17 parts by mass, more preferably 5 to 15 parts by mass, and more preferably 7 to 13 parts by mass per 100 parts by mass of the rubber component for the core wire.

[0081] Co-crosslinking agents (crosslinking aids or co-vulcanizing agents) include known crosslinking aids, such as polyfunctional (iso)cyanurates [e.g., triallyl isocyanurate (TAIC), triallyl cyanurate (TAC), etc.], polydienes (e.g., 1,2-polybutadiene, etc.), metal salts of unsaturated carboxylic acids [e.g., polyvalent metal salts of (meth)acrylic acids such as zinc (meth)acrylate and magnesium (meth)acrylate], oximes (e.g., quinone dioxime, etc.), guanidines (e.g., diphenylguanidine, etc.), polyfunctional (meth)acrylates [e.g., ethylene glycol di(meth)acrylate, alkanediol di(meth)acrylate such as butanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetrapropyl acrylate, etc.]. Examples include alkane polyol poly(meth)acrylates such as la(meth)acrylate, bismaleimides (aliphatic bismaleimides, e.g., alkylene bismaleimides such as N,N'-1,2-ethylenedimaleimide, N,N'-hexamethylenebismaleimide, 1,6'-bismaleimide-(2,2,4-trimethyl)cyclohexane; arene bismaleimides or aromatic bismaleimides, e.g., N,N'-m-phenylenedimaleimide, 4-methyl-1,3-phenylenedimaleimide, 4,4'-diphenylmethanedimaleimide, 2,2-bis[4-(4-maleimoidphenoxy)phenyl]propane, 4,4'-diphenyletherdimaleimide, 4,4'-diphenylsulfonedimaleimide, 1,3-bis(3-maleimoidphenoxy)benzene, etc.). These crosslinking aids can be used alone or in combination of two or more. Among these crosslinking aids, polyfunctional (iso)cyanurates, polyfunctional (meth)acrylates, and bismaleimides (arene bismaleimides such as N,N'-m-phenylenedimaleimide or aromatic bismaleimides) are preferred, and bismaleimides are often used. The addition of crosslinking aids (e.g., bismaleimides) increases the degree of crosslinking and prevents adhesive abrasion.

[0082] The proportion of co-crosslinking agents such as bismaleimides (co-crosslinking agents for core wires) is, in terms of solid content, for example, 5 parts by mass or less, preferably 1 part by mass or less, per 100 parts by mass of the rubber component for core wires, and it is more preferable that the co-crosslinking agent is not included.

[0083] Examples of crosslinking accelerators (vulcanization accelerators) include thiram-based accelerators [e.g., tetramethylthiram monosulfide (TMTM), tetramethylthiram disulfide (TMTD), tetraethylthiram disulfide (TETD), tetrabutylthiram disulfide (TBTD), dipentamethylenethiram tetrasulfide (DPTT), N,N'-dimethyl-N,N'-diphenylthiram disulfide, etc.], and thiazole-based accelerators [e.g., 2-mercaptobenzothiazole, 2-mercaptobenzothiazole subdivisions]. Examples of crosslinking accelerators include lead salts, 2-mercaptothiazoline, dibenzothiazyl disulfide, 2-(4'-morpholinodithio)benzothiazole, sulfenamide accelerators (e.g., N-cyclohexyl-2-benzothiadylsulfenamide (CBS), N,N'-dicyclohexyl-2-benzothiadylsulfenamide), guanidines (diphenylguanidine, di-o-tolylguanidine, etc.), urea or thiourea accelerators (e.g., ethylenethiourea), dithiocarbamates, xanthogenicates, etc. These crosslinking accelerators can be used alone or in combination of two or more. Among these crosslinking accelerators, TMTD, DPTT, and CBS are commonly used.

[0084] The proportion of the crosslinking accelerator (crosslinking accelerator for core wires) may be 15 parts by mass or less (for example, 0 to 15 parts by mass) per 100 parts by mass of the rubber component for core wires, in terms of solid content, for example, 0.1 to 10 parts by mass, preferably 0.2 to 5 parts by mass, more preferably 0.3 to 3 parts by mass, and more preferably 0.5 to 1.5 parts by mass.

[0085] The proportion of the core wire processing agent or processing aid (such as stearic acid) may be 10 parts by mass or less (for example, 0 to 10 parts by mass) per 100 parts by mass of the core wire rubber component, in terms of solid content, for example, 0.1 to 5 parts by mass, preferably 0.3 to 3 parts by mass, and more preferably 0.5 to 3 parts by mass.

[0086] The proportion of the anti-aging agent for the core wire is, in terms of solid content, for example, 0.5 to 15 parts by mass, preferably 1 to 10 parts by mass, more preferably 2.5 to 7.5 parts by mass, and more preferably 3 to 7 parts by mass, per 100 parts by mass of the rubber component for the core wire.

[0087] The proportion of plasticizer for the core wire may be 30 parts by mass or less (for example, 0 to 30 parts by mass) per 100 parts by mass of the rubber component for the core wire, in terms of solid content, for example, 0.5 to 20 parts by mass, preferably 1 to 10 parts by mass, and more preferably 3 to 7 parts by mass.

[0088] The rubber hardness Hs (Type A) of the adhesive rubber layer can be selected from a range of approximately 60 to 90°, preferably 72 to 80°, more preferably 73 to 78°, even more preferably 74 to 78°, and most preferably 75 to 77°. If the rubber hardness is too low, the durability of the belt may decrease, and if it is too high, the adhesive strength may decrease.

[0089] In this application, the rubber hardness of each rubber layer (crosslinked rubber composition) is the value Hs (Type A) measured using a Type A durometer in accordance with the spring durometer hardness test specified in JIS K6253 (2012) (Vulcanized rubber and thermoplastic rubber - Method for determining hardness -). The rubber hardness of each rubber layer may be simply referred to as "rubber hardness". In detail, the rubber hardness of each rubber layer can be measured by the method described in the examples below.

[0090] The tensile strength of the adhesive rubber layer is, for example, 12 to 20 MPa, preferably 13 to 18 MPa, and more preferably 14 to 17 MPa in the belt width direction. If the tensile strength is too low, the lateral pressure resistance may decrease. Conversely, if the tensile strength is too high, the flexibility may decrease.

[0091] In the present application, the tensile strength of each rubber layer (vulcanized rubber composition) is the value of the tensile strength T of each rubber layer, which can be measured by a method conforming to JIS K6251 (2017). Specifically, the tensile strength of each rubber layer can be measured by the method described in the examples below.

[0092] (First rubber layer) The first rubber layer is formed of a first vulcanized rubber composition containing a first rubber component. The first rubber component contained in the first vulcanized rubber composition can be selected from the rubber components exemplified as the rubber components for the core wire, including preferred embodiments. The first rubber component may be a rubber component different from the rubber component for the core wire, but is usually of the same type as the rubber component for the core wire.

[0093] The first vulcanized rubber composition may further contain a filler (first filler). Examples of the first filler include the fillers exemplified as the fillers for the core wire. Among the above fillers, carbon black is preferred. The carbon black can be selected from the carbon blacks exemplified as the fillers for the core wire, including preferred embodiments.

[0094] The proportion of the first filler (particularly carbon black) is, for example, 5 to 100 parts by mass, preferably 10 to 80 parts by mass, more preferably 15 to 50 parts by mass, and still more preferably 20 to 40 parts by mass with respect to 100 parts by mass of the first rubber component. If the proportion of the first filler is too small, the durability of the belt may decrease, and if it is too large, the mechanical properties may decrease.

[0095] The first vulcanized rubber composition may further contain short fibers (first short fibers). Examples of the fibers constituting the first short fibers include the fibers exemplified as the fibers constituting the core wire. The fibers can be used alone or in combination of two or more. Among the above fibers, synthetic fibers, natural fibers, particularly C such as ethylene terephthalate and ethylene-2,6-naphthalate 2-4 alkylene C 8-14Synthetic fibers such as polyester fibers (polyalkylene arylate fibers) and polyamide fibers (aramid fibers, etc.) with arylate as the main constituent unit, cellulose fibers such as cotton fibers, and inorganic fibers such as carbon fibers are commonly used. Among these, rigid fibers with high strength and modulus, such as polyester fibers (especially polyethylene terephthalate fibers and polyethylene naphthalate fibers), polyamide fibers (especially aramid fibers), and cellulose fibers (especially cotton fibers), are preferred, and it is particularly preferable to include fully aromatic polyamide fibers such as aramid fibers. The proportion of aramid fibers may be 1% by mass or more (e.g., 5 to 100% by mass) of the short fibers.

[0096] The average fiber diameter of the first short fibers is, for example, 2 μm or more, preferably 2 to 100 μm, more preferably 3 to 50 μm (e.g., 5 to 50 μm), more preferably 7 to 40 μm, and most preferably 10 to 30 μm. The average length of the short fibers is, for example, 1 to 20 mm, preferably 1.5 to 10 mm, more preferably 2 to 5 mm, and more preferably 2.5 to 4 mm.

[0097] In this application, the average fiber diameter and average length of the short fibers can be determined, for example, by measuring the fiber diameter and length of 10 randomly selected short fibers using a scanning electron microscope or the like, and then calculating the arithmetic mean.

[0098] From the viewpoint of dispersibility and adhesion of the first short fibers in the first crosslinked rubber composition, the first short fibers may be bonded (or surface treated) by conventional methods. Examples include treatment with a treatment solution containing conventional surface treatment agents. Examples of surface treatment methods include the surface treatment agents exemplified as surface treatment agents for the core wires. The surface treatment agents may be used alone or in combination of two or more, and the short fibers may be treated multiple times with the same or different surface treatment agents.

[0099] The first short fibers may be embedded in the first rubber layer, oriented in the belt width direction, in order to suppress compressive deformation of the belt due to pressure from the pulley.

[0100] The proportion of the first short fibers can be selected from a range of approximately 50 parts by mass or less per 100 parts by mass of the first rubber component, for example, 30 parts by mass or less, preferably 10 to 30 parts by mass. If the proportion of the first short fibers is too high, the rubber hardness may become too high and the flexibility may decrease.

[0101] The first crosslinked rubber composition may also, if necessary, further contain other additives as exemplified in the section on crosslinked rubber compositions for core wires.

[0102] Examples of the crosslinking agent (first crosslinking agent) include the crosslinking agents exemplified as crosslinking agents for core wires. The crosslinking agents can be used alone or in combination of two or more. When the rubber component is chloroprene rubber, the first crosslinking agent is preferably a crosslinking agent containing a metal oxide (such as magnesium oxide or zinc oxide), and a combination of a metal oxide and a sulfur-based crosslinking agent is particularly preferred.

[0103] When combining a metal oxide as a crosslinking agent with a sulfur-based crosslinking agent, the proportion of the sulfur-based crosslinking agent is, for example, 0.1 to 50 parts by mass, preferably 1 to 30 parts by mass, and more preferably 3 to 10 parts by mass, per 100 parts by mass of the metal oxide.

[0104] The cocrosslinking agent (first cocrosslinking agent) can be selected from the cocrosslinking agents exemplified as cocrosslinking agents for core wires, including preferred embodiments. The proportion of the first cocrosslinking agent is, for example, 0.1 to 10 parts by mass, preferably 0.5 to 8 parts by mass, more preferably 1 to 5 parts by mass, and more preferably 2 to 4 parts by mass, per 100 parts by mass of the first rubber component.

[0105] The proportion of the first softening agent (oils such as naphthenic oils) may be 30 parts by mass or less (for example, 0 to 30 parts by mass) per 100 parts by mass of the first rubber component, in terms of solid content, for example, 1 to 30 parts by mass, preferably 3 to 20 parts by mass, and more preferably 3 to 10 parts by mass.

[0106] The proportion of the first processing agent or processing aid (such as stearic acid) may be 10 parts by mass or less (for example, 0 to 10 parts by mass) per 100 parts by mass of the first rubber component, in terms of solid content, for example, 0.1 to 5 parts by mass, preferably 0.3 to 3 parts by mass, and more preferably 0.5 to 3 parts by mass.

[0107] The proportion of the first anti-aging agent is, on a solid content basis, for example, 0.5 to 15 parts by mass, preferably 1 to 10 parts by mass, more preferably 2.5 to 7.5 parts by mass, and more preferably 3 to 7 parts by mass, per 100 parts by mass of the first rubber component.

[0108] The rubber hardness Hs (Type A) of the first rubber layer can be selected from a range of approximately 80 to 100°, preferably 83 to 95°, more preferably 85 to 93°, even more preferably 88 to 92°, and most preferably 89 to 91°. If the rubber hardness is too low, the lateral pressure resistance may decrease, and if it is too high, the fit with the pulley groove and flexibility may decrease.

[0109] The tensile strength of the first rubber layer is, for example, 15 to 50 MPa, preferably 20 to 40 MPa, more preferably 23 to 35 MPa, more preferably 25 to 30 MPa, and most preferably 26 to 28 MPa in the belt width direction. If the tensile strength is too low, the lateral pressure resistance may decrease. Conversely, if the tensile strength is too high, the flexibility may decrease.

[0110] (Second rubber layer) The second rubber layer is formed of a second crosslinked rubber composition containing a second rubber component. The second rubber component included in the second crosslinked rubber composition can be selected from the rubber components exemplified as core wire rubber components, including preferred embodiments. The second rubber component may be a different rubber component from the core wire rubber component, but is usually of the same type as the core wire rubber component.

[0111] The second crosslinked rubber composition may further contain a filler (second filler). Examples of the second filler include those exemplified as core wire fillers. Among the fillers, carbon black is preferred. The carbon black can be selected from the carbon blacks exemplified as core wire fillers, including preferred embodiments.

[0112] The proportion of the second filler (especially carbon black) is, for example, 5 to 100 parts by mass, preferably 10 to 80 parts by mass, more preferably 30 to 70 parts by mass, and more preferably 40 to 60 parts by mass, per 100 parts by mass of the second rubber component. If the proportion of the second filler is too low, the durability of the belt may decrease, and if it is too high, the mechanical properties may decrease.

[0113] The second crosslinked rubber composition may further contain short fibers (second short fibers). The fibers constituting the second short fibers can be selected from the fibers exemplified as the first short fibers, including in preferred embodiments. The average fiber diameter and average length of the second short fibers can also be selected from the numerical range of the average fiber diameter and average length of the first short fibers, including in preferred embodiments.

[0114] From the viewpoint of dispersibility and adhesion of the second short fibers in the second crosslinked rubber composition, the second short fibers may be bonded (or surface treated) by conventional methods. Examples of surface treatment methods include treatment with a treatment solution containing a conventional surface treatment agent. Examples of surface treatment agents include the surface treatment agents exemplified as surface treatment agents for the core wire. The surface treatment agents may be used alone or in combination of two or more, and the short fibers may be treated multiple times with the same or different surface treatment agents.

[0115] The second short fibers may be embedded in the second rubber layer, oriented in the belt width direction, in order to suppress compressive deformation of the belt due to pressure from the pulley.

[0116] The proportion of the second short fibers can be selected from a range of approximately 50 parts by mass or less per 100 parts by mass of the second rubber component, for example, 30 parts by mass or less, preferably 10 to 30 parts by mass. If the proportion of the second short fibers is too high, the rubber hardness may become too high and the flexibility may decrease.

[0117] The second crosslinked rubber composition may also, if necessary, further contain other additives as exemplified in the section on crosslinked rubber compositions for core wires.

[0118] Examples of crosslinking agents (second crosslinking agents) include those exemplified as crosslinking agents for core wires. The crosslinking agents can be used alone or in combination of two or more. When the rubber component is chloroprene rubber, the second crosslinking agent is preferably a crosslinking agent containing a metal oxide (such as magnesium oxide or zinc oxide), and a combination of a metal oxide and a sulfur-based crosslinking agent is particularly preferred.

[0119] When combining a metal oxide as a crosslinking agent with a sulfur-based crosslinking agent, the proportion of the sulfur-based crosslinking agent is, for example, 0.1 to 50 parts by mass, preferably 1 to 30 parts by mass, and more preferably 3 to 10 parts by mass, per 100 parts by mass of the metal oxide.

[0120] The cocrosslinking agent (second cocrosslinking agent) can be selected from the cocrosslinking agents exemplified as cocrosslinking agents for core wires, including preferred embodiments. The proportion of the second cocrosslinking agent is, for example, 0.1 to 10 parts by mass, preferably 0.5 to 8 parts by mass, more preferably 1 to 5 parts by mass, and more preferably 2 to 4 parts by mass, per 100 parts by mass of the second rubber component.

[0121] The proportion of the second softening agent (oils such as naphthenic oils) may be 30 parts by mass or less (for example, 0 to 30 parts by mass) per 100 parts by mass of the second rubber component, in terms of solid content, for example, 1 to 30 parts by mass, preferably 3 to 20 parts by mass, and more preferably 3 to 10 parts by mass.

[0122] The proportion of the second processing agent or processing aid (such as stearic acid) may be 10 parts by mass or less (for example, 0 to 10 parts by mass) per 100 parts by mass of the second rubber component, in terms of solid content, for example, 0.1 to 5 parts by mass, preferably 0.3 to 3 parts by mass, and more preferably 0.5 to 3 parts by mass.

[0123] The proportion of the second anti-aging agent is, on a solid content basis, for example, 0.5 to 15 parts by mass, preferably 1 to 10 parts by mass, more preferably 2.5 to 7.5 parts by mass, and more preferably 3 to 7 parts by mass, per 100 parts by mass of the second rubber component.

[0124] The rubber hardness Hs (Type A) of the second rubber layer can be selected from a range of approximately 80 to 100°, preferably 85 to 95°, more preferably 87 to 94°, even more preferably 90 to 93°, and most preferably 92 to 93°. If the rubber hardness is too low, the lateral pressure resistance may decrease, and if it is too high, the fit with the pulley groove and flexibility may decrease.

[0125] The tensile strength of the second rubber layer is, for example, 15 to 50 MPa, preferably 20 to 45 MPa, more preferably 23 to 40 MPa, more preferably 25 to 35 MPa, and most preferably 28 to 32 MPa in the belt width direction. If the tensile strength is too low, the lateral pressure resistance may decrease. Conversely, if the tensile strength is too high, the flexibility may decrease.

[0126] (Characteristics of tie bands) The average thickness of the tie band (thickness a in Figure 3) can be selected from a range of approximately 1.8 to 8 mm, for example, 1.8 to 6 mm, preferably 2 to 5 mm, more preferably 2 to 4 mm (for example, 2 to 3 mm), more preferably 2.5 to 4 mm, and most preferably 2.5 to 3.5 mm. In particular, for the ASABE HA type, the average thickness may be 2 to 5 mm, and for the ASABE HB and HC types, the average thickness may be 2.5 to 4 mm (especially 2.5 to 3.5 mm). If the thickness of the tie band is too small, it may become prone to ring breakage, which may reduce durability, and if it is too large, it may reduce flexibility, which may reduce durability (flexural fatigue resistance).

[0127] The average thickness of the first rubber layer is, for example, 0.1 to 2 times, preferably 0.5 to 1.5 times, and more preferably 0.8 to 1.2 times, the average thickness of the adhesive rubber layer. If the thickness ratio of the first rubber layer to the adhesive rubber layer is too small, the durability of the belt may decrease, and if it is too large, the flexibility of the belt may decrease.

[0128] The average thickness of the second rubber layer is, for example, 0.1 to 2 times, preferably 0.5 to 1.5 times, and more preferably 0.8 to 1.2 times, the average thickness of the adhesive rubber layer. If the thickness ratio of the second rubber layer to the adhesive rubber layer is too small, the durability of the belt may decrease, and if it is too large, the flexibility of the belt may decrease.

[0129] [Wrapped V-belt section] In the coupled V-belt of the present invention, the wrapped V-belt portion connected to the tie band may be any wrapped V-belt portion that does not include a core wire, and is not limited to the wrapped V-belt portion shown in Figure 1 (a wrapped V-belt portion having a structure in which the inner and side surfaces of a V-belt body consisting of a third rubber layer formed on the outer circumference of the belt and a fourth rubber layer laminated on the inner surface of the third rubber layer and having a lower rubber hardness Hs than the third rubber layer are covered with a cover cloth). It may be any wrapped V-belt portion having a V-belt body in which at least the side surfaces are covered with a cover cloth and having an endless shape and a V-shaped cross section. In the coupled V-belt of the present invention, both the left and right side surfaces (V-shaped side surfaces) of the V-shaped cross section are friction transmission surfaces. In the V-shaped cross section, the side with the wider belt width is the outer circumference side, and the side with the narrower belt width is the inner circumference side. The V-angle (α1) of the V-shaped side surface is, for example, 35 to 45°, preferably 36 to 44°, more preferably 37 to 43°, more preferably 38 to 42°, and most preferably 39 to 41° (particularly 40°) with respect to the belt thickness direction.

[0130] (Cover cloth) In the bonded V-belt of the present invention, a V-belt body in which the outer circumferential surface (the surface in contact with the tie band) is not covered with a cover cloth is preferred. In such a V-belt body, the crosslinked rubber composition is exposed on the outer circumferential surface of the V-belt body, which can improve the adhesion strength with the second rubber layer of the tie band. Furthermore, a V-belt body in which only the inner circumferential surface and the sides are covered with a cover cloth, as shown in Figure 1, is particularly preferred because it can improve the adhesion strength with the second rubber layer of the tie band and is also excellent in terms of productivity.

[0131] The cover fabric (outer covering) is made of conventional fabrics. Examples of fabrics include woven fabrics, knitted fabrics (weft knitted fabrics, warp knitted fabrics), and nonwoven fabrics. Of these, woven fabrics such as plain weave, twill weave, and satin weave, and woven or knitted fabrics with intersection angles exceeding 90° but not exceeding 120° are preferred. Woven fabrics commonly used as cover fabrics for transmission belts in general industrial and agricultural machinery [plain weave fabrics with right-angle intersections, and plain weave fabrics with intersection angles exceeding 90° but not exceeding 120° (wide-angle canvas)] are particularly preferred. Furthermore, in applications where durability is required, the fabric may be wide-angle canvas.

[0132] Examples of fibers that make up the fabric include the fibers exemplified as the fibers that make up the core wire. The fibers may be single yarns using only one type of fiber, or composite yarns (such as blended yarns) made by combining two or more types of fibers.

[0133] Of the aforementioned fibers, a blended yarn of polyester fibers and cellulosic fibers is preferred due to its superior mechanical properties and cost-effectiveness.

[0134] Polyester fibers may also be polyalkylene arylate fibers. Examples of polyalkylene arylate fibers include polyethylene terephthalate (PET) fibers, polyethylene naphthalate (PEN) fibers, and other polycrystalline C 2-4 Alkylene-C 8-14 Examples include arylate-based fibers. These polyester fibers can be used individually or in combination of two or more types.

[0135] Cellulosic fibers include cellulose fibers (cellulose fibers derived from plants, animals, or bacteria, etc.) and cellulose derivative fibers. Examples of cellulose fibers include natural plant-derived cellulose fibers (pulp fibers) such as wood pulp (coniferous and hardwood pulp, etc.), bamboo fibers, sugarcane fibers, seed hair fibers (cotton fibers (cotton linters), kapok, etc.), ginseng fibers (hemp, paper mulberry, mitsumata, etc.), and leaf fibers (Manila hemp, New Zealand hemp, etc.); animal-derived cellulose fibers such as ascidian cellulose; bacterial cellulose fibers; and algal cellulose. Examples of cellulose derivative fibers include cellulose ester fibers and regenerated cellulose fibers (rayon, cupro, lyocell, etc.). These cellulose fibers can be used individually or in combination of two or more types. Of these, cotton fibers are preferred.

[0136] The mass ratio of polyester fibers to cellulose fibers is, for example, former / latter = 90 / 10 to 10 / 90, preferably 80 / 20 to 20 / 80, and more preferably 70 / 30 to 30 / 70 (particularly 60 / 40 to 40 / 60).

[0137] The average fineness of the yarns that make up the fabric is, for example, 5 to 30 count, preferably 10 to 25 count, and more preferably 15 to 23 count.

[0138] The basis weight of the fabric (raw material) is, for example, 100-500 g / m². 2 Preferably 200-400 g / m² 2 More preferably 250-350 g / m² 2 That is the case.

[0139] The average thickness of the fabric (raw material) is, for example, 0.1 to 1.5 mm, preferably 0.2 to 1 mm, and more preferably 0.3 to 0.7 mm.

[0140] If the fabric (raw material) is woven, the yarn density of the fabric (density of warp and weft threads) is, for example, 60 to 100 threads / 50 mm, preferably 70 to 90 threads / 50 mm, and more preferably 72 to 80 threads / 50 mm.

[0141] The cover fabric may be single-layered or multi-layered (for example, two to five layers, preferably two to four layers), but from the standpoint of productivity, a single layer (1 ply) or two layers (2 ply) is preferred.

[0142] The cover fabric may be a cloth to which a rubber component is attached in order to improve adhesion to the V-belt body. The cover fabric to which the rubber component is attached may be a cloth that has undergone an adhesive treatment, such as soaking (immersion) in a rubber glue made by dissolving a rubber composition in a solvent, or friction (rubbing) in a solid rubber composition. The adhesive treatment only needs to be performed on at least one surface of the cloth, and it is preferable to treat at least the surface that comes into contact with the V-belt body.

[0143] The rubber components that make up the rubber composition to be attached to the cover cloth (rubber composition for cover cloth) can be selected from the rubber components exemplified as core wire rubber components, including preferred embodiments.

[0144] The rubber composition for the cover fabric may further contain a filler (cover fabric filler). Examples of the cover fabric filler include those exemplified as core wire fillers. Among the fillers, carbon black is preferred. The carbon black can be selected from the carbon blacks exemplified as core wire fillers, including preferred embodiments.

[0145] The proportion of the cover cloth filler (especially carbon black) is, for example, 5 to 80 parts by mass, preferably 10 to 75 parts by mass, more preferably 30 to 70 parts by mass, and more preferably 40 to 60 parts by mass, per 100 parts by mass of the rubber component for the cover cloth.

[0146] The rubber composition for the cover fabric may further contain other additives as exemplified in the section on cross-linked rubber compositions for core wires, if necessary.

[0147] Examples of crosslinking agents (crosslinking agents for cover fabric) include those exemplified as crosslinking agents for core wires. The crosslinking agents can be used alone or in combination of two or more. When the rubber component is chloroprene rubber, a crosslinking agent containing a metal oxide (such as magnesium oxide or zinc oxide) is preferred as the crosslinking agent for cover fabric.

[0148] The proportion of the crosslinking agent for the cover fabric is, depending on the type of crosslinking agent and rubber component, for example, 1 to 20 parts by mass, preferably 3 to 17 parts by mass, more preferably 5 to 15 parts by mass, and more preferably 7 to 13 parts by mass, per 100 parts by mass of the rubber component for the cover fabric, in terms of solid content.

[0149] The proportion of co-crosslinking agents such as bismaleimides (co-crosslinking agents for cover fabric) is, in terms of solid content, for example, 5 parts by mass or less, preferably 1 part by mass or less, per 100 parts by mass of the rubber component for cover fabric, and it is more preferable that the co-crosslinking agent is not included.

[0150] The proportion of the crosslinking accelerator (crosslinking accelerator for cover cloth) may be 15 parts by mass or less (for example, 0 to 15 parts by mass) per 100 parts by mass of the rubber component for cover cloth, in terms of solid content, for example, 0.1 to 10 parts by mass, preferably 0.2 to 5 parts by mass, more preferably 0.3 to 3 parts by mass, and more preferably 0.5 to 1.5 parts by mass.

[0151] The proportion of the processing agent or processing aid (such as stearic acid) for the cover fabric may be 10 parts by mass or less (for example, 0 to 10 parts by mass) per 100 parts by mass of the rubber component for the cover fabric, in terms of solid content, for example, 0.1 to 5 parts by mass, preferably 0.3 to 3 parts by mass, and more preferably 0.5 to 3 parts by mass.

[0152] The proportion of the anti-aging agent for the cover fabric is, in terms of solid content, for example, 0.5 to 15 parts by mass, preferably 1 to 10 parts by mass, more preferably 2.5 to 7.5 parts by mass, and more preferably 3 to 7 parts by mass, per 100 parts by mass of the rubber component for the cover fabric.

[0153] The proportion of plasticizer for the cover fabric is, in terms of solid content, for example, 3 to 50 parts by mass, preferably 5 to 40 parts by mass, more preferably 10 to 30 parts by mass, and more preferably 15 to 25 parts by mass, per 100 parts by mass of the rubber component for the cover fabric.

[0154] The rubber hardness Hs of the crosslinked rubber composition for the cover fabric is, for example, 40 to 70°, preferably 45 to 65°, and more preferably 50 to 60°. The tensile strength of the crosslinked rubber composition to be attached to the outer fabric is, for example, 5 to 20 MPa, preferably 10 to 15 MPa, and more preferably 12 to 13 MPa in the belt width direction.

[0155] The average thickness of the cover fabric (or the average thickness of each layer in the case of a multi-layered structure) is, for example, 0.4 to 2 mm, preferably 0.5 to 1.4 mm. If the cover fabric is too thin, the abrasion resistance may decrease. Conversely, if the cover fabric is too thick, the flexibility of the belt may decrease.

[0156] (V-belt body) The V-belt body may be made of rubber layers formed from a crosslinked rubber composition and is not limited to the two-layer structure shown in Figure 1. It may also be a single-layer structure or a laminated structure with three or more layers. Of these, a laminated structure with two or more layers is preferred in that it can achieve both lateral pressure resistance and flexibility. A V-belt body including a third rubber layer with high hardness (high rigidity) formed on the outer circumference of the belt that contacts the tie band and a fourth rubber layer having a lower rubber hardness Hs than the third rubber layer, a single-layer structure V-belt body, and a two-layer structure V-belt body consisting of the third rubber layer and the fourth rubber layer is particularly preferred. A two-layer structure V-belt body consisting of a third rubber layer and a fourth rubber layer can achieve higher lateral pressure resistance compared to a single-layer structure V-belt body by arranging a third rubber layer with higher hardness than the fourth rubber layer on the outer circumference of the fourth rubber layer, which has a hardness similar to that of a single-layer structure V-belt body.

[0157] The third rubber layer is formed of a third crosslinked rubber composition containing a third rubber component. In the third crosslinked rubber composition, the components and their proportions, such as the third filler and third short fibers, as well as the range of rubber hardness and tensile strength, can be selected from the range of components and their proportions in the second crosslinked rubber composition, including preferred embodiments. The third crosslinked rubber composition is preferably the same type or identical rubber composition as the second crosslinked rubber composition, from the viewpoint of interlayer adhesion with the tie band and productivity.

[0158] The rubber hardness Hs (Type A) of the third rubber layer is greater than that of the fourth rubber layer and can be selected from a range of approximately 80 to 100°, preferably 90 to 95°, more preferably 90 to 94°, even more preferably 90 to 93°, and most preferably 92 to 93°. If the rubber hardness is too low, the lateral pressure resistance may decrease, and if it is too high, the fit with the pulley groove and flexibility may decrease.

[0159] The tensile strength of the third rubber layer is greater than that of the fourth rubber layer, and in the belt width direction, it is, for example, 15 to 50 MPa, preferably 20 to 45 MPa, more preferably 23 to 40 MPa, more preferably 25 to 35 MPa, and most preferably 28 to 32 MPa. If the tensile strength is too low, the lateral pressure resistance may decrease. Conversely, if the tensile strength is too high, the flexibility may decrease.

[0160] The fourth rubber layer is formed of a fourth crosslinked rubber composition containing a fourth rubber component. The fourth rubber component included in the fourth crosslinked rubber composition can be selected from the rubber components exemplified as core wire rubber components, including preferred embodiments. The fourth rubber component may be a different rubber component from the core wire rubber component, but is usually of the same type as the core wire rubber component.

[0161] The fourth crosslinked rubber composition may further contain a filler (fourth filler). Examples of the fourth filler include those exemplified as core wire fillers. Among the fillers, carbon black is preferred. The carbon black can be selected from the carbon blacks exemplified as core wire fillers, including preferred embodiments.

[0162] The proportion of the fourth filler (especially carbon black) is, for example, 5 to 100 parts by mass, preferably 10 to 80 parts by mass, more preferably 15 to 50 parts by mass, and more preferably 20 to 40 parts by mass, per 100 parts by mass of the fourth rubber component. If the proportion of the fourth filler is too low, the durability of the belt may decrease, and if it is too high, the mechanical properties may decrease.

[0163] The fourth crosslinked rubber composition may also, if necessary, further contain other additives as exemplified in the section on crosslinked rubber compositions for core wires.

[0164] Examples of crosslinking agents (fourth crosslinking agent) include those exemplified as crosslinking agents for core wires. The crosslinking agents can be used alone or in combination of two or more. When the rubber component is chloroprene rubber, a crosslinking agent containing a metal oxide (such as magnesium oxide or zinc oxide) is preferred as the crosslinking agent for the cover cloth.

[0165] The proportion of the fourth crosslinking agent is, depending on the type of crosslinking agent and rubber component, for example, 1 to 20 parts by mass, preferably 3 to 17 parts by mass, more preferably 5 to 15 parts by mass, and more preferably 7 to 13 parts by mass, per 100 parts by mass of the fourth rubber component, in terms of solid content.

[0166] The proportion of co-crosslinking agents such as bismaleimides (fourth co-crosslinking agent) is, in terms of solid content, for example, 5 parts by mass or less, preferably 1 part by mass or less, per 100 parts by mass of the fourth rubber component, and it is more preferable that the product does not contain any co-crosslinking agent.

[0167] The proportion of the crosslinking accelerator (fourth crosslinking accelerator) may be 15 parts by mass or less (for example, 0 to 15 parts by mass) per 100 parts by mass of the fourth rubber component, based on solid content, for example, 0.1 to 10 parts by mass, preferably 0.2 to 5 parts by mass, more preferably 0.3 to 3 parts by mass, and more preferably 0.5 to 1.5 parts by mass.

[0168] The proportion of the fourth processing agent or processing aid (such as stearic acid) may be 10 parts by mass or less (for example, 0 to 10 parts by mass) per 100 parts by mass of the fourth rubber component, in terms of solid content, for example, 0.1 to 5 parts by mass, preferably 0.3 to 3 parts by mass, and more preferably 0.5 to 3 parts by mass.

[0169] The proportion of the fourth anti-aging agent is, on a solid content basis, for example, 0.5 to 15 parts by mass, preferably 1 to 10 parts by mass, more preferably 2.5 to 7.5 parts by mass, and more preferably 3 to 7 parts by mass, per 100 parts by mass of the fourth rubber component.

[0170] The proportion of the fourth plasticizer is, on a solid content basis, for example, 3 to 50 parts by mass, preferably 5 to 40 parts by mass, more preferably 10 to 30 parts by mass, and more preferably 15 to 25 parts by mass, per 100 parts by mass of the fourth rubber component.

[0171] The rubber hardness Hs (Type A) of the fourth rubber layer is smaller than that of the third rubber layer, and the difference in rubber hardness Hs between the third and fourth rubber layers [(rubber hardness of the third rubber layer) - (rubber hardness of the fourth rubber layer)] should be, for example, 1° or more (especially 5° or more), preferably 5 to 30° (e.g., 7 to 27°), more preferably 10 to 25° (e.g., 12 to 20°), even more preferably 14 to 20° (e.g., 15 to 19°), and most preferably 14 to 18° (especially 15 to 17°). If the difference in rubber hardness Hs is too small, there is a risk that the flexibility will decrease.

[0172] The rubber hardness Hs (Type A) of the fourth rubber layer can be selected from a range of approximately 60 to 90°, preferably 72 to 80°, more preferably 73 to 78°, even more preferably 74 to 78°, and most preferably 75 to 77°. If the rubber hardness is too low, the lateral pressure resistance may decrease, and if it is too high, the fit with the pulley groove and flexibility may decrease.

[0173] The tensile strength of the fourth rubber layer is lower than that of the third rubber layer, and in the belt width direction, it is, for example, 12 to 20 MPa, preferably 13 to 18 MPa, and more preferably 14 to 17 MPa. If the tensile strength is too low, the lateral pressure resistance may decrease. Conversely, if the tensile strength is too high, the flexibility may decrease.

[0174] The average thickness ratio of the third rubber layer to the fourth rubber layer is third rubber layer / fourth rubber layer = 10 / 90 to 70 / 30, preferably 20 / 80 to 60 / 40, more preferably 25 / 75 to 55 / 45, even more preferably 30 / 70 to 50 / 50, and more preferably 40 / 60 to 45 / 55. If the ratio of the third rubber layer is too small, the lateral pressure resistance may decrease, and if it is too large, the flexibility may decrease.

[0175] If the V-belt body includes other rubber layers in addition to the third and fourth rubber layers, the other rubber layers may be a single layer or multiple layers. Furthermore, the other rubber layers may be laminated on either the outer or inner surface of the fourth rubber layer. The average thickness of the other rubber layers (or the total thickness if multiple other rubber layers exist) may be, for example, 30% or less, preferably 10% or less, and more preferably 5% or less, relative to the average thickness of the V-belt body. That is, it is preferable that the V-belt body includes the third and fourth rubber layers as its main layers. The combined average thickness of the third and fourth rubber layers may be, for example, 70% or more, preferably 90% or more, and more preferably 95% or more, relative to the average thickness of the V-belt body. It is particularly preferable that the V-belt body consists only of the third and fourth rubber layers.

[0176] When the V-belt body has a single-layer structure, the V-belt body is formed of a fifth crosslinked rubber composition containing a fifth rubber component. In the fifth crosslinked rubber composition, the components and proportions of the fifth filler and fifth short fibers, as well as the range of rubber hardness and tensile strength, can be selected from the components and proportions of the fourth filler and fourth short fibers, as well as the range of rubber hardness and tensile strength of the fourth crosslinked rubber composition, including preferred embodiments.

[0177] (Reinforcement layer) The V-belt body may have a laminated structure of two or more rubber layers, and may further have a reinforcing layer interposed between adjacent rubber layers, in order to improve the productivity of wrapped V-belts. If the V-belt body has a laminated structure of three or more rubber layers, a reinforcing layer may be interposed between all rubber layers, but from the standpoint of productivity, it is preferable that one reinforcing layer be interposed for each V-belt body. The position where the reinforcing layer is provided is preferably near the midpoint in the thickness direction of the belt body, or between the midpoint and the outer surface of the belt body.

[0178] Figure 4 shows a schematic partial cross-sectional perspective view of a bonded V-belt, which is another example of the bonded V-belt of the present invention, in which a reinforcing layer is interposed between the third rubber layer and the fourth rubber layer. In this example, it is identical to the bonded V-belt shown in Figure 1, except that a reinforcing layer 5c formed of a fibrous structure is interposed between the third rubber layer 5a and the fourth rubber layer 5b.

[0179] Conventional fabrics can be used as the fibrous structure constituting the reinforcing layer, such as bamboo blind weave, woven fabric, knitted fabric, and net (net-like structure or mesh). Of these, woven fabrics or cloths with a weave structure such as bamboo blind weave or plain weave are preferred because they can achieve both resistance to ring breakage and flexibility in the longitudinal direction of the belt, and also have an excellent balance with productivity, with bamboo blind weave being particularly preferred.

[0180] Among woven bamboo blinds, those containing multiple thread-like bodies extending in the belt width direction are preferred because they can further improve resistance to tensile force acting in the belt width direction. It is particularly preferred to use a woven bamboo blind that contains multiple first thread-like bodies (yarn-like bodies) extending in the belt width direction, and multiple second thread-like bodies that have a lower thread density (arrangement density) than the multiple first thread-like bodies and extend in a direction intersecting the belt width direction.

[0181] In this application, the filamentous material extending in the belt width direction means a filamentous material extending substantially parallel to the belt width direction. "Substantially parallel" means that the angle between the direction in which the filamentous material extends and the belt width direction is, for example, 10° or less (e.g., 0 to 5°), preferably 3° or less (e.g., 0 to 1°, especially approximately 0°).

[0182] The thread density of the first filamentous material (number of threads per 5 cm in the belt length direction) is, for example, 10 to 300 threads / 5 cm, preferably 50 to 200 threads / 5 cm, more preferably 80 to 180 threads / 5 cm, more preferably 100 to 150 threads / 5 cm, and most preferably 110 to 130 threads / 5 cm.

[0183] The thread density of the second filamentous material (number of threads per 5 cm in the belt length direction) is, for example, 1 to 30 threads / 5 cm, preferably 2 to 10 threads / 5 cm, more preferably 2 to 8 threads / 5 cm, more preferably 3 to 7 threads / 5 cm, and most preferably 4 to 6 threads / 5 cm.

[0184] Examples of fibers constituting the first and second filamentous bodies include the fibers exemplified as constituting the first short fibers of the first rubber layer. Of the short fibers, the first filamentous body is preferably a polyester fiber or a polyamide fiber, and particularly preferably an aliphatic polyamide fiber such as polyamide 66 fiber. The second filamentous body is preferably a cellulose fiber, and particularly preferably a cellulose fiber such as cotton fiber.

[0185] When the first filamentous material is a polyester fiber or a polyamide fiber, the fineness of the first filamentous material (total fineness in the case of a multifilament yarn, etc.) is, for example, 100 to 1000 dtex, preferably 200 to 800 dtex, more preferably 300 to 600 dtex, and more preferably 400 to 500 dtex.

[0186] When the second filamentous material is a cellulose fiber such as cotton fiber, the thickness (count) of the second filamentous material is, for example, 5 to 100 count, preferably 10 to 70 count, more preferably 20 to 60 count, and more preferably 30 to 50 count.

[0187] The fibrous structure may be subjected to conventional bonding treatments or surface treatments (for example, treatment with a treatment solution containing an adhesive component) to improve its adhesion to rubber components (crosslinked rubber composition), etc. The bonding treatment method can be selected from the methods described for the first short fibers of the first rubber layer.

[0188] The average thickness of the fiber structure is, for example, 0.1 to 0.7 mm, preferably 0.2 to 0.5 mm, and more preferably 0.3 to 0.4 mm. If the fiber structure is too thin, the effect of improving the productivity of the wrapped bonded V-belt may be reduced. If the fiber structure is too thick, the flexibility of the belt may decrease.

[0189] From the standpoint of improving the adhesion between the fibrous structure and the rubber layer, it is preferable that the reinforcing layer be configured such that the fibrous structure is embedded (sandwiched) within the rubber component (reinforcing layer sandwiching rubber). This configuration involves the fibrous structure being embedded within a crosslinked rubber composition.

[0190] The crosslinked rubber composition constituting the reinforcing layer is not particularly limited, but it is preferable to select from the crosslinked rubber compositions exemplified as crosslinked rubber compositions for core wires that form the adhesive rubber layer, and the preferred embodiment can also be selected from the preferred embodiments of the said crosslinked rubber compositions for core wires.

[0191] The reinforcing layer can be used alone (single layer) or in combination of two or more types (in a laminated structure). Considering productivity and other factors, it is preferable to use the reinforcing layer alone (single layer).

[0192] The average thickness of the reinforcing layer is, for example, 0.4 to 1.4 mm, preferably 0.5 to 1 mm. If the reinforcing layer is too thin, the effect of improving the productivity of the wrapped V-belt may be reduced. Conversely, if the reinforcing layer is too thick, the flexibility of the belt may decrease.

[0193] (Characteristics of the wrapped V-belt section) The average thickness of the wrapped V-belt section may be 6 mm or more, for example, 6 to 20 mm, preferably 7 to 18 mm, and more preferably 8 to 15 mm. If the thickness of the wrapped V-belt section is too small, the area of ​​the friction transmission surface will be small, which may reduce the transmission efficiency.

[0194] The average thickness of the wrapped V-belt section is, for example, 60-90%, preferably 65-90%, more preferably 70-90%, and even more preferably 75-90% of the average thickness of the entire bonded V-belt. If the thickness ratio of the wrapped V-belt section (b / total thickness in Figure 3) is too small, the area of ​​the friction transmission surface will be small, which may reduce the transmission efficiency. If it is too large, it may reduce durability.

[0195] In this application, the average thickness of the wrapped V-belt portion and the entire bonded V-belt is measured by the following method.

[0196] First, the thickness of the "entire connected V-belt" and the "wrapped V-belt section" are measured in an image of the cross-section of the connected V-belt taken with a microscope. Next, one measurement point is selected for each wrapped V-belt section arranged in the width direction of the connected V-belt, and the thickness of the "entire connected V-belt" and the "wrapped V-belt section" are measured at each measurement point. Then, the average thickness is calculated from the thicknesses at each measurement point. That is, for example, in the case of a connected V-belt made up of three wrapped V-belt sections, the average value of the three points is measured.

[0197] When the V-belt body includes a third rubber layer and a fourth rubber layer, the average thickness of the third rubber layer can be selected from a range of, for example, 10 to 70% of the average thickness of the V-belt body, preferably 20 to 60%, more preferably 25 to 55%, even more preferably 30 to 50%, and more preferably 40 to 45%. If the ratio of the third rubber layer is too small, the lateral pressure resistance may decrease, and if it is too large, the flexibility may decrease.

[0198] [Characteristics of wrapped V-belts] The average thickness (height in the belt thickness direction or total thickness in Figure 3) of the wrapped V-belt of the present invention may be 8 mm or more, for example, 8 to 25 mm, preferably 9 to 20 mm, and more preferably 10 to 18 mm. If the thickness of the wrapped V-belt is too small, the area of ​​the friction transmission surface will be small, which may reduce the transmission capacity.

[0199] The belt length of the wrapped V-belt of the present invention may be 3000 mm or more, for example, 3000 to 20000 mm, preferably 5000 to 18000 mm, more preferably 8000 to 15000 mm, and more preferably 10000 to 13000 mm. If the belt length is too small, the effects of the present invention may not be realized.

[0200] In the wrapped V-belt of the present invention, the pitch of the wrapped V-belt portion (the average distance between the central portions of adjacent wrapped V-belt portions) is, for example, 10 to 50 mm, preferably 13 to 40 mm, and more preferably 15 to 30 mm.

[0201] <Method for manufacturing a wrapped V-belt> The wrapped V-belt of the present invention includes a wrapped V-belt precursor manufacturing step of covering a V-belt body precursor with a cover cloth, and a connecting step of connecting a plurality of wrapped V-belt precursors obtained in the above step with tie band precursors including a core wire.

[0202] [Process for manufacturing the precursor of the wrapped V-belt section] In the process of manufacturing the wrapped V-belt precursor, the V-belt body precursor obtained by rolling is cut and subjected to a winding process in which it is wrapped around the mantle, and then subjected to a cutting process in which it is cut to a predetermined belt width.

[0203] Figure 5 is a schematic diagram illustrating the cutting process of the V-belt body precursor consisting of the third and fourth rubber layers. In detail, Figure 5(a) shows a schematic perspective view, and Figure 5(b) shows a schematic enlarged section of Figure 5(a). As shown in Figure 5, the laminate of the uncrosslinked third rubber layer sheet 7a and the fourth rubber layer sheet 7b obtained by rolling is cut and wound onto the mantle. The resulting annular laminate 7 is subjected to a cutting process and cut (sliced) to a predetermined core width (belt width) on the mantle to produce a core (cut annular laminate) 8 consisting of the third rubber layer sheet 8a and the fourth rubber layer sheet 8b. If a reinforcing layer is interposed between the third and fourth rubber layers, the reinforcing layer precursor is made by winding it between the third rubber layer sheet and the fourth rubber layer sheet.

[0204] The annular laminate, cut to a predetermined belt width, is subjected to skiving and cover wrapping processes. Figure 6 is a schematic diagram illustrating the skiving and cover wrapping processes of the core 8 obtained in Figure 5. The cut annular laminate 8 is placed over a pair of pulleys (not shown) and cut into a V shape (skiving process) while rotating. The uncrosslinked V-belt body (V-belt body precursor) 9 obtained by the skiving process is covered with a cover cloth precursor 11 on its sides and bottom (inner circumferential surface) to obtain a wrapped V-belt portion precursor 10.

[0205] [Connection process] In the coupling process, the multiple wrapped V-belt precursors obtained in the previous process are coupled together with tie band precursors that include a core wire. This process will be explained using Figures 7 to 13.

[0206] As shown in Figure 7, in a connecting device 20 for connecting wrapped V-belt precursors, an uncrosslinked wrapped V-belt precursor (a set of multiple wrapped V-belt precursors) 10, held wrapped around a pair of pulleys 23a and 23b, is sandwiched between the pair of pulleys 23a and 23b by two pairs of press molds (a first pair of press molds combining an inner circumferential mold 21a and an outer circumferential mold 21b, and a second pair of press molds combining an inner circumferential mold 22a and an outer circumferential mold 22b). Furthermore, a heating plate 24 for crosslinking the wrapped V-belt precursor 10 is provided between the inner circumferential molds 21a and 22a.

[0207] Figure 8 is a schematic cross-sectional view (cross-sectional view in the belt width direction) showing the state in which the wrapped V-belt precursors are fitted into the press mold during the coupling process. Multiple wrapped V-belt precursors 10 obtained in the wrapped V-belt precursor manufacturing process are fitted into grooves (grooves with an inverted trapezoidal cross-section corresponding to the wrapped V-belts arranged in the belt width direction) formed in the cylindrical or annular inner circumferential mold (bridge-cross-linking mold) 21a.

[0208] Figures 9-11 are schematic cross-sectional views illustrating the process of wrapping a tie band precursor around a wrapped V-belt precursor during the coupling process.

[0209] As shown in Figure 9, in the linking process, first, an uncrosslinked second rubber layer sheet 12 is wrapped around the outer circumferential surfaces of a plurality of wrapped V-belt precursors 10 that are fitted into the groove of the inner circumferential mold 21a (or inner circumferential mold 22a, not shown) and arranged at predetermined intervals in the belt width direction, bridging the gaps between them. Then, an uncrosslinked inner adhesive rubber layer sheet 13 is wrapped over it.

[0210] Next, as shown in Figure 10, the core wire 14 is wrapped around the inner circumferential adhesive rubber layer sheet 13, and then, as shown in Figure 11, the uncrosslinked outer adhesive rubber layer sheet 15 and the uncrosslinked first rubber layer sheet 16 are sequentially wrapped around the core wire 14 to obtain a tie band precursor, which is a laminate of the second rubber layer sheet 12, the inner circumferential adhesive rubber layer sheet 13, the core wire 14, the outer circumferential adhesive rubber layer sheet 15, and the first rubber layer sheet 16.

[0211] Figure 12 is a schematic cross-sectional view illustrating the crosslinking process of the wrapped bond V-belt precursor. The wrapped bond V-belt precursor, consisting of the obtained wrapped V-belt precursor and tie band precursor, is subjected to a crosslinking process (vulcanization process) in which an outer peripheral mold 21b is placed on the first rubber layer sheet 16, and the material is sandwiched between the inner peripheral mold 21a and the outer peripheral mold 21b, and then pressurized and heated.

[0212] Figure 13 is a schematic cross-sectional view illustrating the process of cutting a cross-linked wrapped bonded V-belt precursor. As shown in Figure 13, a cross-linked sleeve (wrapped bonded V-belt precursor) 17, in which multiple wrapped V-belt sections obtained by the cross-linking process are connected by tie bands, is cut to a predetermined width to obtain a bonded V-belt having a predetermined number of wrapped V-belt sections. [Examples]

[0213] The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples. Details of the materials used in the examples and comparative examples, and the evaluation methods for the examples and comparative examples are shown below.

[0214] [Materials used] (Rubber composition) The materials incorporated into the rubber composition are as follows:

[0215] Chloroprene rubber: "PM-40" manufactured by Denka Co., Ltd. Magnesium oxide: "Kyowa Mag 30" manufactured by Kyowa Chemical Industry Co., Ltd. Stearic acid: "Stearic acid Tsubaki" manufactured by NOF Corporation. Anti-aging agent (octyl diphenylamine): "Nonflex OD-3" manufactured by Seiko Chemical Co., Ltd. Carbon Black ISAF: "Seast 3" manufactured by Tokai Carbon Co., Ltd. Silica: "ULTRASIL(registered trademark) VN3" manufactured by Evonik Japan Co., Ltd., BET specific surface area 175 m² 2 / g Plasticizer: ADEKA Corporation "RS-700" Crosslinking accelerator: "Noxellar TT" manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Zinc Oxide: "Zinc Oxide 3 Types" manufactured by Seido Chemical Industry Co., Ltd. Naphthenic oil: "NS-900" manufactured by Idemitsu Kosan Co., Ltd. Co-crosslinking agent (N,N'-m-phenylenedimaleimide): "Balnock PM" manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Aramid short fibers: "Conex short fibers" manufactured by Teijin Limited, with an average fiber length of 3 mm and an average fiber diameter of 14 μm. These short fibers were bonded with RFL solution (2.6 parts resorcinol, 1.4 parts 37% formalin, 17.2 parts vinylpyridine-styrene-butadiene copolymer latex (manufactured by Zeon Corporation), and 78.8 parts water) and have a solid content adhesion rate of 6% by mass. Sulfur (powdered sulfur): Manufactured by Migen Chemical Co., Ltd.

[0216] (Core wire 1) Two bundles of 1670 dtex aramid fibers were joined together and twisted in the S direction with a twist coefficient of 3.0 to produce a pre-twisted yarn. Three of these pre-twisted yarns were then joined together and twisted in the Z direction with a twist coefficient of 3.0 to produce a twisted cord (multi-twisted yarn) with a total fineness of 10020 dtex and a diameter of 1.19 mm. This treated cord, which was then bonded, was used as the core wire.

[0217] (Core wire 2) Three bundles of 1670 dtex (1000 filaments) aramid fibers were joined together and twisted in the S direction with a twist coefficient of 3.0 to produce a pre-twisted yarn. Five of these pre-twisted yarns were then joined together and twisted in the Z direction with a twist coefficient of 3.0 to produce a twisted cord (multi-twisted yarn) with a total fineness of 25050 dtex (15000 filaments) and a diameter of 1.9 mm. This treated cord, which was then bonded, was used as the core wire.

[0218] [Adhesive rubber layer, rubber composition for friction rubber] Rubber composition A, as shown in Table 2, was mixed in a Banbury mixer, and this mixed rubber was passed through a calender roll to produce an uncrosslinked rolled rubber sheet of a predetermined thickness, which was used to prepare a sheet for the adhesive rubber layer. Rubber composition B, also shown in Table 2, was mixed in a Banbury mixer to prepare a lump-shaped uncrosslinked rubber composition for friction. Furthermore, the hardness and tensile strength of the crosslinked material of each rubber composition were measured and the results are shown in Table 2. The uncrosslinked rolled rubber sheet formed from rubber composition A was used not only as a sheet for the adhesive rubber layer, but also as a precursor for the reinforcing layer and a precursor for the tie band connecting reinforcing layer.

[0219] [Table 2]

[0220] [Rubber composition for the 1st to 4th rubber layers] Rubber compositions C to E, as shown in Table 3, were mixed in a Banbury mixer. This mixed rubber was then passed through a calender roll to produce uncrosslinked rolled rubber sheets of a predetermined thickness, which were used to prepare the sheets for the first to fourth rubber layers. Furthermore, the hardness and tensile strength of the crosslinked material of each rubber composition were measured and the results are also shown in Table 3.

[0221] [Table 3]

[0222] [Rubber hardness Hs of cross-linked rubber] Each rubber layer sheet (uncrosslinked rubber sheet) was press-heated at a temperature of 160°C, a pressure of 2.5 MPa, and a time of 30 minutes to produce a crosslinked rubber sheet (100 mm × 100 mm × 2 mm thickness). A laminate of three of the obtained crosslinked rubber sheets was used as a sample, and the rubber hardness Hs (Type A) of the crosslinked rubber sheet was measured using a Type A durometer in accordance with the spring-type durometer hardness test specified in JIS K 6253 (2012) (Vulcanized rubber and thermoplastic rubber - Method for determining hardness -). For friction, a lump of uncrosslinked rubber composition B was prepared by sampling a test specimen from the lump of rubber and passing it through a calender roll to prepare an uncrosslinked rolled rubber sheet of the specified thickness.

[0223] [Tensile strength of cross-linked rubber] Cross-linked rubber sheets prepared for measuring the rubber hardness Hs of cross-linked rubber were used as samples, and dumbbell-shaped (Type 5) test specimens were prepared in accordance with JIS K 6251 (2017). For samples containing short fibers, dumbbell-shaped test specimens were taken so that the direction of arrangement of the short fibers (arrangement direction) was the tensile direction. Then, both ends of the test specimen were grasped with a chuck (gripping device), and the test specimen was pulled at a speed of 500 mm / min until it broke. The tensile strength was defined as the value obtained by dividing the maximum tensile force recorded by the initial cross-sectional area of ​​the test specimen (tensile strength T).

[0224] [Reinforcement layer precursor (treated bamboo blind)] A reinforcing layer precursor was prepared by applying adhesive treatment and rubber sheet lamination treatment to a bamboo blind. Specifically, a single-twist cord made of 470 dtex nylon 66 (wire diameter 0.22 mm) was used as the warp thread and a 40 count cotton yarn (wire diameter 0.1 mm) was used as the weft thread. A bamboo blind-like fabric was woven with a warp density of 120 threads / 50 mm and a weft density of 5 threads / 50 mm. This fabric was then immersed in RFL solution (a mixture of 2.6 parts by mass of resorcinol, 1.4 parts by mass of 37% formalin, 17.2 parts by mass of vinylpyridine-styrene-butadiene copolymer latex (manufactured by Nippon Zeon Co., Ltd.), and 78.8 parts by mass of water), dried, and then uncrosslinked rubber sheets of rubber composition A were laminated to both the front and back surfaces to prepare a treated bamboo blind (thickness approximately 0.7 mm).

[0225] [Cover fabric (woven fabric for outer covering) precursor (woven fabric with rubber)] The woven fabric was subjected to adhesive and friction treatments to create a precursor for the cover fabric. Specifically, a 20s / 3 (20 count, 3-ply) blended yarn, consisting of polyester fibers and cotton blended in a mass ratio of 50 / 50, was used for the warp and weft threads. The fabric was plain woven with a warp density of 75 threads / 50mm and a weft density of 75 threads / 50mm, resulting in a weight of 280g / m². 2 The canvas was immersed in RFL solution (a mixture of 2.6 parts by mass of resorcinol, 1.4 parts by mass of 37% formalin, 17.2 parts by mass of vinylpyridine-styrene-butadiene copolymer latex (manufactured by Zeon Corporation), and 78.8 parts by mass of water), dried, and then subjected to a wide-angle treatment so that the angle between the warp and weft threads was 120 degrees. The resulting wide-angle canvas was then subjected to a friction treatment by rubbing rubber composition B shown in Table 2 onto both sides to create a rubber-coated woven fabric (basis weight approximately 500 g / m²). 2 A sample with a thickness of approximately 0.6 mm was prepared.

[0226] [Precursor fabric for tie bands (woven fabric with elastic)] The woven fabric was subjected to adhesive and friction treatments to create a preliminary fabric for tie bands. Specifically, a 10s / 3 (10 count, 3-ply) blended yarn, consisting of polyester fibers and cotton blended in a mass ratio of 50 / 50, was used for the warp and weft threads. The fabric was plain woven with a warp density of 44 threads / 50mm and a weft density of 44 threads / 50mm, resulting in a weight of 280g / m². 2The canvas was immersed in RFL solution (a mixture of 2.6 parts by mass of resorcinol, 1.4 parts by mass of 37% formalin, 17.2 parts by mass of vinylpyridine-styrene-butadiene copolymer latex (manufactured by Zeon Corporation), and 78.8 parts by mass of water), dried, and then subjected to a wide-angle treatment so that the angle between the warp and weft threads was 120 degrees. The resulting wide-angle canvas was then subjected to a rubber-coated woven fabric (basis weight approximately 1050 g / m²) by rubbing rubber composition B shown in Table 2 onto both sides (friction treatment). 2 A sample with a thickness of approximately 1.0 mm was prepared.

[0227] [Precursor for connecting and reinforcing layer for tie bands (treated bamboo blind)] A bamboo blind was subjected to adhesive treatment and rubber sheet lamination treatment to prepare a precursor for a tie band connecting reinforcement layer. Specifically, a bamboo blind-like fabric was woven using a 470dtex nylon 66 single-twist cord (wire diameter 0.22 mm) as the warp thread and a 40-count cotton yarn (wire diameter 0.1 mm) as the weft thread, with a warp density of 120 threads / 50 mm and a weft density of 5 threads / 50 mm. This fabric was then immersed in RFL solution (a mixture of 2.6 parts by mass of resorcinol, 1.4 parts by mass of 37% formalin, 17.2 parts by mass of vinylpyridine-styrene-butadiene copolymer latex (manufactured by Nippon Zeon Co., Ltd.), and 78.8 parts by mass of water), dried, and then laminated with uncrosslinked rubber sheets of rubber composition A on both the front and back surfaces to prepare a treated bamboo blind (thickness approximately 1.5 mm).

[0228] [Endurance driving test] (Test machine) The test used a multi-axle running test machine with the multi-axle layout shown in Figure 14.

[0229] This testing machine has a pulley layout consisting of a drive pulley (Dr1), driven pulleys (Dn2 and Dn3), and tension pulley (Ten4) as shown in Table 4, arranged in the order of drive pulley (Dr1) 31, driven pulley (Dn2) 32, driven pulley (Dn3) 33, and tension pulley (Ten4) 34. This testing machine is configured to verify durability performance (presence or absence of belt damage) under various conditions (load, etc.).

[0230] [Table 4]

[0231] (Test method) The coupled V-belt of each test specimen was run under the conditions shown in Table 5 and the loads shown in Table 6. The belt was visually inspected to check for damage and evaluated according to the following criteria. As shown in Table 6, various loads were applied to the driven pulleys Dn2 and Dn3 during the run.

[0232] [Table 5]

[0233] [Table 6]

[0234] (Endurance run evaluation criteria) a: Completed 240 hours without any abnormalities such as cracks or delamination. b: Completed 240 hours of use, with some minor cracks and delamination observed (but not to the extent that it would affect performance). c: Abnormalities such as cracks or peeling were observed during the race, and the race was not completed.

[0235] [Lateral vibration test] (Test machine) The test used a two-axle running test machine with the two-axle layout shown in Figure 15(a).

[0236] This testing machine has pulleys arranged on two axes, with a layout consisting of a drive pulley (Dr) 41 and a driven pulley (Dn) 42 as shown in Table 7. This testing machine is configured to verify durability performance (presence or absence of belt damage) under various conditions (load, etc.).

[0237] [Table 7]

[0238] (Test Method) The connecting V-belts of each test specimen were run in a circular path under the conditions shown in Table 8, and the amount of lateral runout while the belt was running in a circle was measured from the belt thickness direction with a laser displacement meter ((Fiber Sensor) manufactured by Keyence Corporation) 44 and from the belt width direction with a laser displacement meter 45 with respect to the connecting belt 43 as shown in Fig. 15(b). The amount of lateral runout was measured by rotating the belt two full turns and taking the average value of the amount of lateral runout in the third turn.

[0239] As comparative data, Fig. 16 shows the data of the amount of lateral runout measured for 33 samples of a conventional lap-connected V-belt (the connecting V-belt obtained in Comparative Example 2) in which the ASABE HB-shaped lap V-belt portion with the core wire arranged was connected with a tie band without the core wire. In this data, Fig. 17 shows the change in the amplitude for one turn of the belt of the sample of Belt No. 2, and the amount of lateral runout of the sample of Belt No. 2 was 5.8 mm. The lateral runout test was judged according to the following criteria. Judgments a and b were set as the passing levels.

[0240]

Table 8

[0241] (Lateral Runout Judgment Criteria) a: 3 mm or less b: More than 3 mm and 5 mm or less c: More than 5 mm

[0242] [Overall Judgment] The criteria for the overall judgment (ranking) as a connecting V-belt that can solve this problem were judged according to the criteria shown in Table 9 from the results of the judgments in the above two evaluation items (endurance running test, lateral runout test), and a C-rank or higher was considered to be passing.

[0243]

Table 9

[0244] (Comparative Example 1) (Preparation of Unvulcanized Rubber Belt) Uncrosslinked sheets for the fourth rubber layer, the third rubber layer, and the adhesive rubber layer were wound in order around the outer surface of the mantle (cylindrical drum). A core wire (core wire 1) was then wound spirally around the outer surface, and then sheets for the adhesive rubber layer and the third rubber layer were wound in order around the outer surface to form a cylindrical uncrosslinked sleeve in which the uncrosslinked rubber layers and the core wire were laminated. The resulting uncrosslinked sleeve was cut circumferentially while positioned on the outer surface of the mantle to form an annular core (uncrosslinked rubber belt). The short fibers in the third rubber layer sheet were arranged to be approximately parallel to the belt width direction.

[0245] (Skibing process and cover cloth coating process (coating process)) The core (uncrosslinked rubber belt) was removed from the mantle, and both sides of the uncrosslinked rubber belt were cut at a predetermined angle (skiving process) to form a V-shaped cross-section. The uncrosslinked V-belt body (V-belt body precursor) obtained by the skiving process was covered with a cover cloth precursor (cover wrapping process) on its sides and bottom (inner circumferential surface) to form a wrapped V-belt section precursor (uncrosslinked wrapped V-belt section).

[0246] (Preparation of bonded V-belts (connection process)) Next, multiple uncrosslinked wrapped V-belt sections containing the core wire obtained in the above step were connected with tie band precursors that did not contain the core wire. Specifically, the uncrosslinked wrapped V-belt sections were fitted into the grooves of the inner circumferential mold, and tie band connecting reinforcement layer precursors (treated bamboo blinds) and tie band fabric precursors (rubber-coated woven fabrics) were wrapped in this order to bridge the outer surfaces of the six uncrosslinked wrapped V-belt sections arranged at predetermined intervals in the belt width direction, thereby creating tie band precursors, which are laminates of tie band connecting reinforcement layer precursors and tie band fabric precursors. The treated bamboo blinds were arranged so that the longitudinal direction of the warp threads was approximately parallel to the belt width direction, and the longitudinal direction of the weft threads was approximately parallel to the belt circumference direction.

[0247] The tie band precursor and the six uncrosslinked wrapped V-belt sections, set in this manner, were sandwiched between the inner and outer molds and pressurized to 1.2 MPa. A crosslinking molding treatment (vulcanization treatment) was then performed at a heating temperature of 160°C to produce a crosslinked belt in which the six wrapped V-belt sections were connected and joined by tie bands.

[0248] The resulting cross-linked belt was cut to create a wrapped bonded V-belt with three wrapped V-belt sections. The resulting wrapped bonded V-belt was an ASABE HA type bonded V-belt (belt length 10196 mm, V-belt section thickness 8.04 mm, tie band thickness 2.0 mm). A wrapped bonded V-belt with seven wrapped V-belt sections was also created using the same method.

[0249] (Example 1) (Preparation of uncrosslinked rubber belts) An uncrosslinked sheet for the fourth rubber layer, a reinforcing layer precursor (treated bamboo blind), and a sheet for the third rubber layer were sequentially wound around the outer surface of a mantle (cylindrical drum) to form a cylindrical uncrosslinked sleeve in which the uncrosslinked rubber layer and the reinforcing layer precursor were laminated. The resulting uncrosslinked sleeve was cut circumferentially while positioned on the outer surface of the mantle to form an annular core (uncrosslinked rubber belt). The short fibers in the third rubber layer sheet were arranged to be approximately parallel to the belt width direction, and the warp threads of the treated bamboo blind were also arranged to be approximately parallel to the belt width direction.

[0250] (Skibing process and cover cloth coating process (coating process)) The core (uncrosslinked rubber belt) was removed from the mantle, and both sides of the uncrosslinked rubber belt were cut at a predetermined angle (skiving process) to form a V-shaped cross-section. The uncrosslinked V-belt body (V-belt body precursor) obtained by the skiving process was covered with a cover cloth precursor (cover wrapping process) on its sides and bottom (inner circumferential surface) to form a wrapped V-belt section precursor (uncrosslinked wrapped V-belt section).

[0251] (Preparation of bonded V-belts (connection process)) Next, the multiple uncrosslinked wrapped V-belt sections obtained in the above step were fitted into the grooves of the inner circumferential mold. The second rubber layer sheet and the adhesive rubber layer sheet were then wound around the outer circumferential surfaces of the six uncrosslinked wrapped V-belt sections, which were arranged at predetermined intervals in the belt width direction, bridging them. A core wire (core wire 1) was then wound spirally around its outer circumferential surface, and the adhesive rubber layer sheet and the first rubber layer sheet were then wound around its outer circumferential surface in order to form a tie band precursor. The short fibers in the first rubber layer sheet and the second rubber layer sheet were arranged to be approximately parallel to the belt width direction, and the warp threads of the processed blind were arranged so that their longitudinal direction was approximately parallel to the belt width direction, and their longitudinal direction was approximately parallel to the belt circumference direction.

[0252] The tie band precursor and the six uncrosslinked wrapped V-belt sections, set in this manner, were sandwiched between the inner and outer molds and pressurized to 1.2 MPa. A crosslinking molding treatment (vulcanization treatment) was then performed at a heating temperature of 160°C to produce a crosslinked belt in which the six wrapped V-belt sections were connected and joined by tie bands.

[0253] The obtained cross-linked belt was cut to produce a wrapped bonded V-belt having three wrapped V-belt sections. The resulting wrapped bonded V-belt was an ASABE HA type bonded V-belt (belt length 10196 mm, V-belt section thickness 8.04 mm, tie band thickness 2.0 mm). The thickness of the first rubber layer was 0.4 mm, the adhesive rubber layer thickness was 1.2 mm, the second rubber layer thickness was 0.4 mm, the third rubber layer thickness was 2.0 mm, and the fourth rubber layer thickness was 4.84 mm. A wrapped bonded V-belt having seven wrapped V-belt sections was also produced using the same method.

[0254] (Example 2) An ASABE HA-type bonded V-belt was fabricated in the same manner as in Example 1, except that the thickness of the tie band was 3.0 mm. The thickness of the first rubber layer was 0.9 mm, the thickness of the adhesive rubber layer was 1.2 mm, the thickness of the second rubber layer was 0.9 mm, the thickness of the third rubber layer was 2.0 mm, and the thickness of the fourth rubber layer was 4.84 mm.

[0255] (Example 3) An ASABE HA-shaped joined V-belt was produced in the same manner as in Example 1, except that the thickness of the tie band was 5.0 mm. The thickness of the first rubber layer was 1.9 mm, the thickness of the adhesive rubber layer was 1.2 mm, the thickness of the second rubber layer was 1.9 mm, the thickness of the third rubber layer was 2.0 mm, and the thickness of the fourth rubber layer was 4.84 mm.

[0256] Table 10 shows the evaluation results of the endurance running test and the lateral runout test for the joined V-belts obtained in Comparative Example 1 and Examples 1 to 3.

[0257]

Table 10

[0258] As is clear from the results in Table 10, for the joined V-belt of Comparative Example 1 in which the core wire was arranged in the wrapped V-belt portion, although the endurance running was judged as b, the amount of lateral runout was large and judged as c (failed), so the overall judgment was D rank. In contrast, for the joined V-belts of Examples 1 to 3 in which the core wire was arranged in the tie band, although the endurance running was judged as b, the amount of lateral runout was reduced to the level of a or b judgment (passed), and the overall judgment was B rank.

[0259] (Comparative Example 2) An ASABE HB-shaped joined V-belt (belt length 10196 mm, V-belt portion thickness 10.74 mm, tie band thickness 2.0 mm) was produced in the same manner as in Comparative Example 1, except that the wrapped V-belt portion was HB-shaped and core wire 2 was used as the core wire.

[0260] (Example 4) An ASABE HB-shaped joined V-belt (belt length 10196 mm, V-belt portion thickness 10.74 mm, tie band thickness 2.0 mm) was produced in the same manner as in Example 1, except that the wrapped V-belt portion was HB-shaped. The thickness of the first rubber layer was 0.4 mm, the thickness of the adhesive rubber layer was 1.2 mm, the thickness of the second rubber layer was 0.4 mm, the thickness of the third rubber layer was 3.7 mm, and the thickness of the fourth rubber layer was 5.84 mm.

[0261] (Example 5) An ASABE HB type bonded V-belt was fabricated in the same manner as in Example 4, except that the thickness of the tie band was set to 3.0 mm and core wire 2 was used as the core wire. The thickness of the first rubber layer was 0.5 mm, the thickness of the adhesive rubber layer was 2.0 mm, the thickness of the second rubber layer was 0.5 mm, the thickness of the third rubber layer was 3.7 mm, and the thickness of the fourth rubber layer was 5.84 mm.

[0262] (Example 6) An ASABE HB type bonded V-belt was fabricated in the same manner as in Example 5, except that the thickness of the tie band was 5.0 mm. The thickness of the first rubber layer was 1.5 mm, the thickness of the adhesive rubber layer was 2.0 mm, the thickness of the second rubber layer was 1.5 mm, the thickness of the third rubber layer was 3.7 mm, and the thickness of the fourth rubber layer was 5.84 mm.

[0263] (Example 7) An ASABE HB type bonded V-belt was fabricated in the same manner as in Example 5, except that the thickness of the tie band was 8.8 mm. The thickness of the first rubber layer was 3.4 mm, the thickness of the adhesive rubber layer was 2.0 mm, the thickness of the second rubber layer was 3.4 mm, the thickness of the third rubber layer was 3.7 mm, and the thickness of the fourth rubber layer was 5.84 mm.

[0264] Table 11 shows the evaluation results of the durability running test and lateral sway test for the coupled V-belts obtained in Comparative Example 2 and Examples 4-7.

[0265] [Table 11]

[0266] As is clear from the results in Table 11, the bonded V-belt of Comparative Example 2, in which the core wire was positioned in the wrapped V-belt section, received a B rating for endurance running, but a large amount of lateral sway resulted in a C rating (failure), resulting in an overall rating of D. In contrast, the bonded V-belts of Examples 4-6, in which the core wire was positioned within the tie band, received an A or B rating for endurance running, but the amount of lateral sway improved to an A rating (pass), resulting in an overall rating of A or B. In the bonded V-belt of Example 7, when the tie band increased to 8.8 mm, the flexibility decreased, resulting in a shorter lifespan during endurance running. Therefore, the amount of lateral sway was a B rating, the endurance running rating was a C rating, and the overall rating was C.

[0267] (Comparative Example 3) An ASABE HC-type bonded V-belt (belt length 10196 mm, V-belt thickness 14.84 mm, tie band thickness 2.0 mm) was fabricated using the same method as in Comparative Example 1, except that the wrapped V-belt section was of the HC type and core wire 2 was used as the core wire.

[0268] (Example 8) An ASABE HC-type bonded V-belt (belt length 10196 mm, V-belt thickness 14.84 mm, tie band thickness 2.0 mm) was manufactured in the same manner as in Example 1, except that the wrapped V-belt section was of the HC type. The thickness of the first rubber layer was 0.4 mm, the thickness of the adhesive rubber layer was 1.2 mm, the thickness of the second rubber layer was 0.4 mm, the thickness of the third rubber layer was 5.8 mm, and the thickness of the fourth rubber layer was 7.84 mm.

[0269] (Example 9) An ASABE HC type bonded V-belt was fabricated in the same manner as in Example 8, except that the thickness of the tie band was set to 3.0 mm and core wire 2 was used as the core wire. The thickness of the first rubber layer was 0.5 mm, the thickness of the adhesive rubber layer was 2.0 mm, the thickness of the second rubber layer was 0.5 mm, the thickness of the third rubber layer was 5.8 mm, and the thickness of the fourth rubber layer was 7.84 mm.

[0270] (Example 10) An ASABE HC type bonded V-belt was fabricated in the same manner as in Example 9, except that the thickness of the tie band was 5.0 mm. The thickness of the first rubber layer was 1.5 mm, the thickness of the adhesive rubber layer was 2.0 mm, the thickness of the second rubber layer was 1.5 mm, the thickness of the third rubber layer was 5.8 mm, and the thickness of the fourth rubber layer was 7.84 mm.

[0271] Table 12 shows the evaluation results of the durability running test and lateral sway test for the bonded V-belts obtained in Comparative Example 3 and Examples 8-10.

[0272] [Table 12]

[0273] As is clear from the results in Table 12, the coupled V-belt of Comparative Example 3, in which the core wire was positioned in the wrapped V-belt section, received a B rating for durability testing, but the amount of lateral sway was large, resulting in a C rating (failure), and thus an overall rating of D. In contrast, the coupled V-belts of Examples 8-10, in which the core wire was positioned within the tie band, received an A or B rating for durability testing, but the amount of lateral sway was reduced to the level of an A or B rating (pass), resulting in an overall rating of A or B.

[0274] From the above results, it was found that, with the configuration of the present invention, regardless of the scale of the connected V-belt, the lateral runout (or twisting) of the connected V-belt is reduced, and the durability against belt breakage and ring breakage can be improved. [Industrial applicability]

[0275] The wrapped V-belt of the present invention can be used in general industrial machinery such as compressors, generators, and pumps, as well as agricultural machinery such as combine harvesters, rice transplanters, and lawnmowers. However, because it has excellent resistance to lateral pressure, it is particularly suitable for high-load machinery used in long-span layouts under heavy loads. Examples of such high-load machinery include large agricultural machinery used in Europe and the United States, such as tillers, vegetable transplanters, transplanters, binders, combine harvesters, vegetable harvesters, threshing machines, bean cutters, corn harvesters, potato harvesters, and beet harvesters. [Explanation of Symbols]

[0276] 1…Coupled V-belt 2…First rubber layer 3…Adhesive rubber layer 3a…core wire 4…Second rubber layer 5…V-belt body 5a...Third rubber layer 5b...Fourth rubber layer 5c…Reinforcement layer 6…Cover cloth T... Thai band V... Wrapped V-belt section

Claims

1. A combined V-belt comprising a plurality of wrapped V-belt sections arranged in the belt width direction and tie bands for connecting these wrapped V-belt sections, The wrapped V-belt portion is formed from a V-belt body and a cover cloth that covers at least the sides of the V-belt body. The average thickness of the wrapped V-belt section is 60-90% of the average thickness of the entire combined V-belt. The tie band includes a core wire arranged to extend in the longitudinal direction of the belt, A coupled V-belt in which the wrapped V-belt portion does not include a core wire.

2. The bonded V-belt according to claim 1, wherein the tie band includes an adhesive rubber layer containing the core wire.

3. The bonded V-belt according to claim 2, wherein the tie band comprises a first rubber layer formed on the outer circumference of the adhesive rubber layer and a second rubber layer formed between the adhesive rubber layer and the wrapped V-belt portion.

4. The bonded V-belt according to claim 1 or 2, wherein the V-belt body comprises a third rubber layer formed on the outer circumference of the belt and a fourth rubber layer having a lower rubber hardness Hs (Type A) than the third rubber layer.

5. The bonded V-belt according to claim 4, wherein a reinforcing layer containing a fibrous structure is interposed between the third rubber layer and the fourth rubber layer.

6. The coupling V-belt according to claim 1 or 2, wherein the cover cloth does not cover the outer circumferential surface of the V-belt body.

7. A coupling V-belt according to claim 1 or 2, wherein the belt length is 3000 mm or more.

8. A method for manufacturing a bonded V-belt according to claim 1 or 2, comprising a wrapped V-belt precursor manufacturing step of covering a V-belt body precursor with a cover cloth, and a bonding step of bonding a plurality of wrapped V-belt precursors obtained in the above step with tie band precursors including a core wire.

9. A belt transmission mechanism comprising a coupled V-belt according to claim 1 or 2 and a pulley.

10. A belt transmission mechanism according to claim 9, used in agricultural machinery.

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