Coupling v-belt, method of 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 combined V-belt in which multiple wrapped V-belts are wound around pulleys or the like simultaneously in high-load, long-span (long center-to-center distance) layouts such as large-scale agricultural machinery, a manufacturing method thereof, and a belt transmission mechanism. [Background technology]

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

[0003] A single V-belt is used in applications where power can be transmitted by a single belt. For example, in high-load environments that require enormous power transmission while repeatedly rotating forward and backward on multiple shafts, such as large-scale agricultural machinery used on large farms in Europe and the United States, multiple V-belts must be used simultaneously. In other words, multiple V-belts must be wrapped around the pulleys of the belt transmission mechanism in parallel (multiple loops) to rotate and run the machine.

[0004] However, when multiple V-belts are used, tension differences can occur between the parallel V-belts, potentially impairing stable power transmission. Furthermore, contact between adjacent V-belts can cause the inner and outer peripheries of the belt to reverse direction, potentially resulting in overturning. Furthermore, the running layout of the belt transmission mechanism in large-scale agricultural machinery in Europe and the United States has a very long center-to-center distance between the pulleys around which the V-belt is wound, which can cause the V-belt to vibrate significantly during running. Furthermore, if the lengths of the multiple belts are not uniform, vibrations can occur.

[0005] Therefore, in an environment where multiple V-belts run in parallel, a combined belt (combined V-belt) is used, which is configured by connecting multiple annular V-belt sections having the same or corresponding configuration as the V-belts in the belt width direction. This combined belt is configured as a V-belt in which multiple belt sections are arranged in parallel and connected with tie bands (connecting members such as fabric).

[0006] The joined V-belts are disclosed, for example, in the following documents, in which various tie bands are proposed:

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

[0008] Japanese Utility Model Application Laid-Open Publication No. 55-45082 (Patent Document 2) discloses a tie band in which two layers of rubber-backed saddle cords are cross-laminated with an intermediate rubber layer interposed therebetween.

[0009] Japanese Utility Model Laid-Open Publication No. 55-181050 (Patent Document 3) discloses a tie band having one or more short fiber mixed rubber layers.

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

[0011] Japanese Patent Laid-Open Publication No. 03-033536 (Patent Document 5) discloses a fastening band as a tie band, in which an adhesive rubber layer and a rubber-attached saddle record are laminated together.

[0012] Japanese Patent Laid-Open Publication No. 04-351350 (Patent Document 6) discloses a tie band portion having a rectangular cross section made only of rubber as a tie band, and a combined V-belt for power transmission including this tie band portion has the entire outer periphery, including the tie band portion, covered with a single outer canvas covering.

[0013] Japanese Patent Application Laid-Open Publication No. 2020-003061 (Patent Document 7) discloses a woven fabric having a rubber composition imprinted into the weave as a tie band.

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

[0015] [Patent Document 1] Special Publication No. 47-34432 [Patent Document 2] Japanese Utility Model Application Publication No. 55-45082 [Patent Document 3] Japanese Utility Model Application Publication No. 55-181050 [Patent Document 4] Japanese Patent Application Publication No. 55-135244 [Patent Document 5] Japanese Patent Application Publication No. 03-033536 [Patent Document 6] Japanese Patent Application Publication No. 04-351350 [Patent Document 7] Japanese Patent Publication No. 2020-003061 [Patent Document 8] Japanese Patent Publication No. 2022-085864 Summary of the Invention [Problem to be solved by the invention]

[0016] In the combined V-belts of Patent Documents 1 to 8, multiple V-belts are connected in a parallel arrangement and can run, so even if a difference in tension occurs between the parallel V-belt portions during running, vibration and overturning of the V-belt portions can be suppressed to some extent. However, depending on the usage environment, this suppression may be insufficient, and if a difference in elongation occurs in the V-belt portions running in parallel, lateral vibration (or twisting) of the V-belt occurs, which may cause the V-belt portions to ride up onto the pulleys, leading to belt breakage or ring breakage.

[0017] Therefore, the object of the present invention is to provide a combined V-belt, a manufacturing method thereof, and a belt transmission mechanism that can reduce the lateral vibration (or twisting) of the combined V-belt by reducing the difference in elongation of the wrapped V-belt portions that run in parallel.

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

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

[0020] As a result of extensive research to achieve the above object, the inventors discovered that by arranging the core wire of a wrapped combined V-belt in a tie band, the difference in elongation of the V-belt portions running in parallel can be reduced, thereby reducing the lateral vibration (or twisting) of the combined V-belt, and thus completed the present invention.

[0021] That is, the present invention includes the following aspects.

[0022] Aspect [1]: A combined V-belt including a plurality of wrapped V-belt portions arranged in the belt width direction and a tie band for connecting these wrapped V-belt portions, The wrapped V-belt portion is formed of a V-belt body and a cover fabric that covers at least the side surface of the V-belt body, and A bonded V-belt, wherein the tie band includes a core wire.

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

[0024] Aspect [3]: A combined V-belt according to aspect [1] or [2], wherein the tie band includes a first rubber layer formed on the outer circumferential side of the adhesive rubber layer, and a second rubber layer formed between the adhesive rubber layer and the wrapped V-belt portion.

[0025] Aspect [4]: ​​A combined V-belt according to any one of aspects [1] to [3], wherein the V-belt body includes a third rubber layer formed on the outer periphery of the belt and a fourth rubber layer having a rubber hardness Hs (Type A) lower than that of the third rubber layer.

[0026] Aspect [5]: The joined V-belt of aspect [4], wherein a reinforcing layer including a fiber structure is interposed between the third rubber layer and the fourth rubber layer.

[0027] Aspect [6]: A combined V-belt according to any one of aspects [1] to [5], in which the cover cloth does not cover the outer peripheral surface of the V-belt body.

[0028] Aspect [7]: The combined V-belt according to any one of aspects [1] to [6], wherein the average thickness of the wrapped V-belt portion is 60 to 90% of the average thickness of the entire combined V-belt.

[0029] Aspect [8]: A combined V-belt according to any one of aspects [1] to [7], wherein the belt length is 3000 mm or more.

[0030] Aspect [9]: A method for manufacturing a joined V-belt according to any one of aspects [1] to [8], including a wrapped V-belt portion precursor fabrication step of covering a V-belt main body precursor with a cover cloth, and a connecting step of connecting multiple wrapped V-belt portion precursors obtained in the above step with tie band precursors including core wires.

[0031] Aspect

[10] : A belt transmission mechanism comprising the combined V-belt according to any one of aspects [1] to [8] above, and a pulley.

[0032] Aspect

[11] : The belt transmission mechanism of aspect

[10] used in agricultural machinery.

[0033] In the present application, a numerical range expressed as "A to B" means "A or more and B or less," and is used in the sense that both the numerical values ​​A and B at the both ends are included. [Effects of the Invention]

[0034] In the present invention, the core wire of the wrapped combined V-belt is arranged in the tie band, which reduces the difference in elongation between the V-belt portions running in parallel, thereby reducing the lateral vibration (or twisting) of the combined V-belt.Furthermore, the durability of the belt against breakage and rotational breakage can be improved. [Brief explanation of the drawings]

[0035] [Figure 1] FIG. 1 is a schematic, partially sectional perspective view showing an example of a wrapped, coupled V-belt according to the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional view showing a conventional bonded V-belt. [Figure 3] FIG. 3 is a schematic cross-sectional view comparing a wrapped bonded V-belt (b) of the present invention with a V-ribbed belt (a). [Figure 4] FIG. 4 is a schematic partial cross-sectional perspective view showing another example of the wrapped coupled V-belt of the present invention. [Figure 5] FIG. 5 is a schematic diagram for explaining the cutting process in the wrapped V-belt portion precursor manufacturing process. [Figure 6] FIG. 6 is a schematic diagram for explaining the skiving process and the cover winding process in the wrapped V-belt portion precursor manufacturing process. [Figure 7] FIG. 7 is a schematic overall view showing the joining process. [Figure 8] FIG. 8 is a schematic cross-sectional view showing a state in which the wrapped V-belt portion precursor is fitted into the press mold in the connecting step. [Figure 9] FIG. 9 is a schematic cross-sectional view showing a state in which a sheet for a second rubber layer and a sheet for an inner adhesive rubber layer are wound around the wrapped V-belt portion precursor in the connecting step. [Figure 10]FIG. 10 is a schematic cross-sectional view showing a state in which a core wire is wound around the sheet for the adhesive rubber layer on the inner periphery side of FIG. 9 in the connecting step. [Figure 11] FIG. 11 is a schematic cross-sectional view showing a state in which an outer circumferential adhesive rubber layer sheet and a first rubber layer sheet are wound around the core wire of FIG. 10 in a connecting step. [Figure 12] FIG. 12 is a schematic cross-sectional view for explaining the cross-linking treatment of the wrapped bonded V-belt precursor. [Figure 13] FIG. 13 is a schematic cross-sectional view illustrating a process for cutting a cross-linked wrapped bonded V-belt precursor. [Figure 14] FIG. 14 is a diagram showing a multi-axis layout, which is the arrangement for the durability running test of the embodiment. [Figure 15] FIG. 15 is a diagram showing the biaxial layout of the lateral shake (sideways vibration) test of the embodiment and the method for measuring the amount of lateral shake. [Figure 16] FIG. 16 is a graph showing data obtained by measuring the amount of lateral deflection of a conventional wrapped coupled V-belt. [Figure 17] FIG. 17 is a graph showing the change in amplitude over one revolution of the wrapped coupled V-belt measured in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0036] Wrapped V-belt The combined V-belt (wrapped combined V-belt) of the present invention will be described in detail below, with reference to the accompanying drawings as necessary. In the following description, the same reference numerals may be used to designate identical or functionally common elements (or members).

[0037] Fig. 1 is a schematic, partially sectional perspective view showing an example of a coupled V-belt of the present invention. As shown in Fig. 1, this coupled V-belt 1 has three wrapped V-belt portions V arranged parallel to each other at intervals in the belt width direction (direction B in Fig. 1). The outer peripheral surfaces of the three wrapped V-belt portions V are connected by a tie band (connecting member) T including a core wire 3a extending in the belt length direction (circumferential direction, direction A in Fig. 1).

[0038] The tie band T is formed of an adhesive rubber layer 3 including the core wires 3a, a first rubber layer 2 laminated on the outer circumferential 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 surface and side surfaces of a V-belt main body 5, which consists of a third rubber layer 5a formed on the outer periphery of the belt and a fourth rubber layer 5b laminated on the inner periphery of the third rubber layer 5a and having a rubber hardness Hs (Type A) lower than that of the third rubber layer 5a, are covered with a cover cloth 6.

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

[0041] Thus, in conventional combined V-belts, the tie bands are made of fabric or the like, and the cords are embedded in the wrapped V-belt portion. In contrast, in the combined V-belt of the present invention, the cords are embedded in the tie bands, resulting in a significant structural difference. When the core layer (adhesive rubber layer) containing the cords and the cords are arranged in each V-belt portion, as in conventional combined V-belts, the arrangement of the cords varies from V-belt portion to V-belt portion. This is presumably because, even if the arrangement is the same in the design (drawing), manufacturing variations occur in the actual spinning (the arrangement does not match the drawing). This has a particularly significant impact on long belts, as the arrangement varies from portion to portion along the length of a single V-belt portion. Furthermore, in the field of power transmission belts, the ease with which a belt stretches is expressed as an index of "elongation rate" or "elastic modulus," and this "elastic modulus" is governed by the elastic modulus of the arranged cords (fibers), and is determined by adjusting the type of fiber and arrangement density (number of cords per width) of the cords, so the arrangement of the cords also affects the belt's stretch. In this way, if there is variation in the arrangement of the cords along the length of a single V-belt section, and if there is also variation between each of the parallel V-belt sections, there will be a large difference in the belt stretch between the V-belt sections, and it can be assumed that lateral vibration (or twisting) will occur in the combined V-belt.

[0042] In contrast, in the present invention, the cords (particularly the cords embedded in the adhesive rubber layer) are arranged inside the tie bands rather than in each V-belt portion, which makes the arrangement of the cords within the combined V-belt (position in the thickness direction, spacing between cords, etc.) relatively uniform. With this arrangement, the cords can be arranged with only one spinning series during manufacturing, which reduces variation between spinnings.

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

[0044] [Differences from V-ribbed belts] V-ribbed belts are widely used as belts for driving accessories mounted on engines of standard automobiles. As shown in Fig. 3(a), a V-ribbed belt has a structure with multiple ribs 61 on its inner peripheral surface, and these ribs 61 are formed from a compressed rubber layer 64. An adhesive rubber layer 63 containing core wires 63a is laminated on the outer peripheral surface of this compressed rubber layer 64, and a tension rubber layer 62 is further laminated on the outer peripheral surface of this adhesive rubber layer 63. The V-ribbed belt 60 has ribs 61 formed only from a rubber layer, and therefore the core wires are not embedded in the ribs, which is common to both the wrapped bonded V-belt of the present invention and the V-ribbed belt.

[0045] However, V-ribbed belts are used in environments where a high degree of flexibility (flexibility) is important, as they are repeatedly bent forward and backward in a narrow space, in order to run in a layout that follows the structure of an automobile engine. Therefore, the layout of a V-ribbed belt is characterized by a relatively short belt length, a tendency for the belt to be thin, and the required transmission capacity is small.

[0046] In contrast, the wrapped coupled V-belt of the present invention is a belt for use in the belt transmission mechanism of large-scale agricultural machinery used on large farms in Europe and the United States, etc. The belt length is long according to the scale of the agricultural machinery, and it is used in a running layout with an extremely long center distance (span length) between the pulleys around which the belt is wound. In addition, since a high transmission capacity is required, a large friction transmission surface is required.

[0047] Due to these differences in running layouts for each application, the belt length is a maximum of 3,000 mm for a V-ribbed belt, while it can be as long as 10,000 mm for a wrapped connected V-belt. Because a wrapped connected V-belt is so long and has a very long center-to-center distance between the pulleys, the lateral vibration (or twisting) caused by the difference in elongation of the V-belt portions running in parallel, which is a problem of the present invention, occurs significantly, whereas a V-ribbed belt, which is short in length and has a short span length, does not have the problem of the present invention.

[0048] In the present invention, a dimensional design specific to wrapped connected V-belts (not conceivable with V-ribbed belts) is used as a means for solving problems specific to wrapped connected V-belts used in such large-scale agricultural machinery, and therefore the two belts have significant differences in shape and structure. For example, Fig. 3 shows the sizes of a V-ribbed belt and a wrapped connected V-belt, and in Fig. 3(b) for the wrapped connected V-belt, the pitch between adjacent wrapped V-belt portions V is shown as the rib pitch, a indicates the thickness of the tie band T, and b indicates the thickness of the wrapped V-belt portion. On the other hand, in Fig. 3(a) for the V-ribbed belt, the thickness of the rib portion corresponding to the thickness of the wrapped V-belt portion is shown as b, and the thickness obtained by subtracting the thickness of the rib portion from the total thickness is shown as a.

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

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

[0051] [Table 1]

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

[0053] Wrapped bonded V-belts are larger overall (larger overall thickness and larger rib pitch) than V-ribbed belts.

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

[0055] Rib height b is a design parameter that determines the area of ​​the friction transmission surface, so the size of rib height b determines the power transmission capacity of a unit rib (unit V-belt section). Compared to V-ribbed belts, wrapped combined V-belts have a larger dimension of b and account for a larger proportion of the total thickness, so they can be used under high load conditions that V-ribbed belts cannot achieve, and achieve a high power transmission capacity.

[0056] In fact, the load on a transmission belt when driving ancillary equipment in an automobile engine is about 1.5 kW per rib, so V-ribbed belts are designed to handle load conditions of this level. On the other hand, the load conditions for the belt transmission mechanism of large-scale agricultural machinery are about 25 kW per rib, so wrapped connected V-belts must be designed to handle load conditions of this level. If a V-ribbed belt were used under the load conditions of a connected V-belt, the area of ​​the friction transmission surface 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 joined V-belt of the present invention, the tie band (joining member) may contain a core wire, but it may also be a tie band in which the core wire is embedded in a rubber layer formed from a cross-linked rubber composition. From the viewpoint of improving durability, a tie band in which a first rubber layer, an adhesive rubber layer containing the core wire, and a second rubber layer are laminated in this order from the outer periphery is preferred.

[0058] (core wire) The core wires are not particularly limited, but are usually twisted cords arranged at a predetermined interval in the width direction of the belt. The core wires are arranged to extend in the longitudinal direction of the belt and may be arranged in parallel with the longitudinal direction of the belt at a predetermined pitch. However, from the viewpoint of productivity, they are usually arranged in a spiral shape, extending in parallel with the longitudinal direction of the belt at a predetermined pitch. When the core wires are arranged in a spiral shape, the angle of the core wire with respect to the longitudinal direction of the belt may be, for example, 5° or less, and from the viewpoint of belt running performance, an angle closer to 0° is preferable. Furthermore, the pitch or interval, which is the distance between the centers of adjacent cores (particularly the spinning pitch of the core wires), 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 may be in contact with the cross-linked rubber composition that constitutes the adhesive rubber layer, and for example, a portion of the core wire may be embedded in the cross-linked rubber composition. However, from the viewpoint of improving durability, a form in which the core wire is not exposed on the surface of the adhesive rubber layer (a form in which the entire core wire is completely embedded in the adhesive rubber layer) is preferred.

[0060] Examples of fibers constituting the core wire include polyolefin fibers (e.g., polyethylene fibers, polypropylene fibers, etc.), polyamide fibers [e.g., aliphatic polyamide fibers (nylon fibers) such as polyamide 6 fibers, polyamide 66 fibers, and polyamide 46 fibers, and aramid fibers, etc.], polyalkylene arylate fibers [e.g., polyethylene terephthalate (PET) fibers, polytrimethylene terephthalate (PTT) fibers, polybutylene terephthalate (PBT) fibers, polyethylene naphthalate (PEN) fibers, etc.]. 2-4 Alkylene C 8-14Examples of such fibers include synthetic fibers such as arylate fibers, vinyl alcohol fibers (polyvinyl alcohol fibers, ethylene-vinyl alcohol copolymer fibers, vinylon fibers, etc.), and polyparaphenylenebenzobisoxazole (PBO) fibers; cellulose fibers (cellulose fibers such as cotton and hemp, and fibers of cellulose derivatives), natural or semi-synthetic fibers such as wool; and inorganic fibers such as carbon fibers. These fibers can be used alone or in combination of two or more.

[0061] Among the above fibers, C ethylene terephthalate, ethylene-2,6-naphthalate, etc. are preferred in terms of high modulus. 2-4 Alkylene-C 8-14 Synthetic fibers such as polyester fibers (polyalkylene arylate fibers) and polyamide fibers (e.g., aramid fibers) whose main structural unit is arylate, and inorganic fibers such as carbon fibers are commonly used, with polyester fibers (particularly polyethylene terephthalate fibers and polyethylene naphthalate fibers) and polyamide fibers (particularly aramid fibers) being preferred, and wholly aromatic polyamide fibers such as aramid fibers being particularly preferred because of their excellent abrasion resistance. The aramid fibers may be commercially available products such as those under the trade names "Conex (registered trademark)," "Nomex (registered trademark)," "Kevlar (registered trademark)," "Technora," and "Twaron (registered trademark)."

[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 10,000 dtex (particularly, 500 to 5,000 dtex). The multifilament yarn may contain, for example, about 100 to 5,000 filaments, preferably 500 to 4,000 filaments, and more preferably 1,000 to 3,000 filaments.

[0063] The core wire can usually be a twisted cord (e.g., double twist, single twist, Lang twist, etc.) using multifilament yarn. 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 even more preferably 1.1 to 2 mm.

[0064] When the core wire is embedded in the adhesive rubber layer, it may be surface-treated to improve adhesion to the cross-linked rubber composition that forms the adhesive rubber layer. Examples of surface treatment methods include treatment with a treatment liquid containing a conventional surface treatment agent. Examples of surface treatment agents include an RFL liquid containing resorcinol (R), formaldehyde (F), and rubber or latex (L) (e.g., an RFL liquid in which resorcinol (R) and formaldehyde (F) form a condensate (RF condensate), and the rubber or latex (L) contains, for example, vinylpyridine-styrene-butadiene copolymer rubber), epoxy compounds, polyisocyanate compounds, silane coupling agents, and cross-linked rubber compositions (e.g., cross-linked rubber compositions containing wet-process white carbon, primarily composed of hydrated silica, which contains surface silanol groups and is advantageous for increasing the chemical bonding strength with rubber). These surface treatment agents may be used alone or in combination, and the core wire may be treated multiple times sequentially with the same or different surface treatment agents. The core wire is preferably treated with at least an RFL liquid for adhesion.

[0065] (Adhesive rubber layer) The adhesive rubber layer is formed of a crosslinked rubber composition containing the cords. The crosslinked rubber composition may be a crosslinked rubber composition containing a rubber component commonly used as a rubber composition for wrapped V-belts (crosslinked rubber composition for cords).

[0066] (A) Rubber component The rubber component (cord rubber component) contained in the cross-linked rubber composition for a cord can be selected from known vulcanizable or cross-linkable 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), and hydrogenated products of the diene rubbers, such as hydrogenated nitrile rubber (including mixed polymers of hydrogenated nitrile rubber and unsaturated carboxylic acid metal salts)), 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, and fluororubber. These rubber components can be used alone or in combination.

[0067] Among these, ethylene-α-olefin elastomers [ethylene-α-olefin-based rubbers such as ethylene-propylene copolymer (EPM) and ethylene-propylene-diene terpolymer (EPDM)] and chloroprene rubber are commonly used because of the ease with which crosslinking agents and crosslinking accelerators diffuse. In particular, when the rubber component for the cord is used in a high-load environment, chloroprene rubber and EPDM are preferred because of their excellent balance of mechanical strength, weather resistance, heat resistance, cold resistance, oil resistance, adhesiveness, and the like. Furthermore, chloroprene rubber is particularly preferred because, in addition to the above properties, it also has excellent abrasion resistance. The chloroprene rubber may be either sulfur-modified or non-sulfur-modified.

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

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

[0070] (B) Filler The crosslinked rubber composition for the cord may further contain a filler (core filler) in addition to the rubber component for the cord. Examples of fillers include carbon black, silica (reinforcing silica), clay, calcium carbonate, talc, and mica. These fillers can be used alone 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-average 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. To enhance the reinforcing effect, carbon black may have a small particle size, and the average particle size of carbon black is, for example, 5 to 38 nm, preferably 10 to 35 nm, and more preferably 15 to 30 nm. Examples of small particle size carbon black include SAF, ISAF-HM, ISAF-LM, HAF-LS, HAF, and HAF-HS. SAF, ISAF, and HAF are conventional carbon black classifications, and all correspond to small particle size carbon blacks known as hard carbon. Specifically, the average particle size of SAF is 19 nm, that of ISAF is 22 nm, and that of HAF is 28 nm. These carbon blacks can be used alone or in combination.

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

[0073] Silica includes dry silica, wet silica, surface-treated silica, etc. Silica can also be classified by production method, for example, into dry-process white carbon, wet-process white carbon, colloidal silica, precipitated silica, and gel-process silica (silica gel). These silicas can be used alone or in combination of two or more. Among these, wet-process white carbon, which is primarily composed of hydrated silica, is preferred because it has many surface silanol groups and has a strong chemical bond with rubber.

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

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

[0076] The proportion of the filler for the cord is, for example, 1 to 100 parts by mass, preferably 10 to 80 parts by mass, further preferably 30 to 70 parts by mass, and even more preferably 40 to 60 parts by mass, relative to 100 parts by mass of the rubber component for the cord. If the proportion of the filler for the cord 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 the reinforcing silica relative to 100 parts by mass of carbon black 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. 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 cross-linked rubber composition for the core wire may contain, as necessary, other additives such as a cross-linking agent (or vulcanizing agent), a co-cross-linking agent (cross-linking aid), a cross-linking accelerator, a cross-linking retarder, a metal oxide (calcium oxide, barium oxide, iron oxide, copper oxide, titanium oxide, aluminum oxide, etc.), a softener (oils such as paraffin oil and naphthenic oil), a processing agent or processing aid (for example, a fatty acid such as stearic acid, a fatty acid metal salt such as metal stearate, a fatty acid amide such as stearamide, wax, paraffin, etc.), an adhesion improver [for example, a resorcinol-formaldehyde co-condensate (RF condensate), an amino resin (a condensate of a nitrogen-containing cyclic compound and formaldehyde, for example, hexamethylol melamine, hexaalkoxymethyl melamine (hexamethoxymethyl melamine, hexabutoxymethyl melamine, etc.)], etc. The resin composition may contain, for example, a melamine resin (such as methylol urea), a urea resin (such as methylol benzoguanamine resin), a co-condensation product thereof (such as a resorcinol-melamine-formaldehyde co-condensation product), an antioxidant (such as an antioxidant, a heat-resistant agent, a flex crack inhibitor, or an antiozonant), a plasticizer (such as an aliphatic carboxylic acid ester plasticizer (such as an adipate ester plasticizer or a sebacate ester plasticizer), an aromatic carboxylic acid ester plasticizer (such as a phthalate ester plasticizer or a trimellitate ester plasticizer), an oxycarboxylic acid ester plasticizer, a phosphate ester plasticizer, an ether plasticizer, or an ether ester plasticizer), a colorant, a tackifier, a lubricant, a coupling agent (such as a silane coupling agent), a stabilizer (such as an ultraviolet absorber or a heat stabilizer), a flame retardant, or an antistatic agent. The metal oxide may also function as a crosslinking agent. In the adhesion improver, the resorcinol-formaldehyde co-condensate and the amino resin may be an initial condensate (prepolymer) of resorcinol and / or a nitrogen-containing cyclic compound (such as melamine) with formaldehyde.

[0079] As the crosslinking agent (core crosslinking agent), conventional components can be used depending on the type of rubber component, and examples thereof include metal oxides (magnesium oxide, zinc oxide, lead oxide, etc.), organic peroxides (diacyl peroxide, peroxy ester, 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 chlorides (sulfur monochloride, sulfur dichloride, etc.). These crosslinking agents can be used alone or in combination of two or more. When the rubber component is chloroprene rubber, metal oxides (magnesium oxide, zinc oxide, etc.) may be used as the core crosslinking agent.

[0080] The proportion of the crosslinking agent for the cord can be selected from the range of, for example, about 1 to 20 parts by mass, calculated as solid content, per 100 parts by mass of the rubber component for the cord, depending on the types of crosslinking agent and rubber component. For example, the proportion of the metal oxide as the 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 even more preferably 7 to 13 parts by mass, per 100 parts by mass of the rubber component for the cord.

[0081] Examples of the co-crosslinking agent (crosslinking aid or co-agent) include known crosslinking aids, such as polyfunctional (iso)cyanurates [e.g., triallyl isocyanurate (TAIC), triallyl cyanurate (TAC)], polydiene (e.g., 1,2-polybutadiene), metal salts of unsaturated carboxylic acids [e.g., (meth)acrylic acid polyvalent metal salts such as zinc (meth)acrylate and magnesium (meth)acrylate], oximes (e.g., quinone dioxime), guanidines (e.g., diphenyl guanidine), polyfunctional (meth)acrylates [e.g., alkanediol di(meth)acrylates such as ethylene glycol di(meth)acrylate and butanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetrahydrofuran, etc.], and the like. Examples of crosslinking aids include alkane polyol poly(meth)acrylates such as methyl methacrylate, bismaleimides (aliphatic bismaleimides, such as alkylene bismaleimides such as N,N'-1,2-ethylenedimaleimide, N,N'-hexamethylenebismaleimide, and 1,6'-bismaleimide-(2,2,4-trimethyl)cyclohexane; arene bismaleimides or aromatic bismaleimides, such as N,N'-m-phenylenedimaleimide, 4-methyl-1,3-phenylenedimaleimide, 4,4'-diphenylmethanedimaleimide, 2,2-bis[4-(4-maleimidophenoxy)phenyl]propane, 4,4'-diphenyletherdimaleimide, 4,4'-diphenylsulfonedimaleimide, and 1,3-bis(3-maleimidophenoxy)benzene). These crosslinking aids can be used alone or in combination. Among these crosslinking aids, polyfunctional (iso)cyanurates, polyfunctional (meth)acrylates, and bismaleimides (arene bismaleimides or aromatic bismaleimides such as N,N'-m-phenylenedimaleimide) are preferred, and bismaleimides are often used. The addition of a crosslinking aid (for example, bismaleimides) increases the degree of crosslinking and can prevent adhesive wear and other problems.

[0082] The proportion of the co-crosslinking agent (core co-crosslinking agent) such as bismaleimides, converted into solid content, is, for example, 5 parts by mass or less, preferably 1 part by mass or less, per 100 parts by mass of the core rubber component, and it is more preferable that no co-crosslinking agent is contained.

[0083] Examples of crosslinking accelerators (vulcanization accelerators) include thiuram accelerators [e.g., tetramethylthiuram monosulfide (TMTM), tetramethylthiuram disulfide (TMTD), tetraethylthiuram disulfide (TETD), tetrabutylthiuram disulfide (TBTD), dipentamethylenethiuram tetrasulfide (DPTT), N,N'-dimethyl-N,N'-diphenylthiuram disulfide, etc.], thiazole accelerators [e.g., 2-mercaptobenzothiazole, 2-mercaptobenzothiazole subunits, etc.], Examples of crosslinking accelerators include lead salts, 2-mercaptothiazoline, dibenzothiazyl disulfide, 2-(4'-morpholinodithio)benzothiazole, sulfenamide accelerators (e.g., N-cyclohexyl-2-benzothiazylsulfenamide (CBS), N,N'-dicyclohexyl-2-benzothiazylsulfenamide, etc.), guanidines (diphenylguanidine, di-o-tolylguanidine, etc.), urea or thiourea accelerators (e.g., ethylenethiourea), dithiocarbamates, and xanthates. These crosslinking accelerators can be used alone or in combination. Among these crosslinking accelerators, TMTD, DPTT, and CBS are commonly used.

[0084] The proportion of the crosslinking accelerator (crosslinking accelerator for cord) may be 15 parts by mass or less (e.g., 0 to 15 parts by mass) relative to 100 parts by mass of the rubber component for cord, calculated as solid content, and is, for example, 0.1 to 10 parts by mass, preferably 0.2 to 5 parts by mass, further preferably 0.3 to 3 parts by mass, and further preferably 0.5 to 1.5 parts by mass.

[0085] The proportion of the cord processing agent or processing aid (such as stearic acid) may be 10 parts by mass or less (e.g., 0 to 10 parts by mass) per 100 parts by mass of the cord rubber component, calculated as solid content, and is, 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 antioxidant for the cord, calculated as solid content, relative to 100 parts by mass of the rubber component for the cord is, 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 even more preferably 3 to 7 parts by mass.

[0087] The proportion of the plasticizer for the cord, converted into solid content, may be 30 parts by mass or less (e.g., 0 to 30 parts by mass) per 100 parts by mass of the rubber component for the cord, 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, for example, from the range of about 60 to 90°, and is preferably 72 to 80°, further 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 a 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 - Determination of 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 in the belt width direction 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.

[0091] In the present application, the tensile strength of each rubber layer (crosslinked rubber composition) is the value of the tensile strength T of each rubber layer, which can be measured by a method in accordance with JIS K6251 (2017). In detail, 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 crosslinked rubber composition containing a first rubber component. The first rubber component contained in the first crosslinked rubber composition can be selected from the rubber components exemplified as the rubber component for the cord, including preferred embodiments. The first rubber component may be a rubber component different from the rubber component for the cord, but is usually the same type as the rubber component for the cord.

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

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

[0095] The first crosslinked 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 fibers, synthetic fibers and natural fibers, particularly C fibers such as ethylene terephthalate and ethylene-2,6-naphthalate, are preferred. 2-4 Alkylene C 8-14Commonly used fibers include synthetic fibers such as polyester fibers (polyalkylene arylate fibers) whose main structural unit is arylate, polyamide fibers (e.g., aramid fibers), cellulose fibers such as cotton fibers, and inorganic fibers such as carbon fibers. Among these, stiff fibers with high strength and modulus are preferred, such as polyester fibers (especially polyethylene terephthalate fibers and polyethylene naphthalate fibers), polyamide fibers (especially aramid fibers), and cellulose fibers (especially cotton fibers), and wholly aromatic polyamide fibers such as aramid fibers are particularly preferred. The proportion of aramid fibers in the staple fibers may be 1% by mass or more (e.g., 5 to 100% by mass).

[0096] The first short fibers have an average fiber diameter of, 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 the present application, the average fiber diameter and average length of the short fibers can be determined by, for example, measuring the fiber diameter and length of 10 randomly selected short fibers using a scanning electron microscope or the like and calculating the arithmetic mean value.

[0098] From the viewpoint of dispersibility and adhesiveness of the first short fibers in the first crosslinked rubber composition, the first short fibers may be subjected to an adhesion treatment (or surface treatment) by a conventional method. Examples of such methods include a treatment method using a treatment liquid containing a conventional surface treatment agent. Examples of surface treatment methods include the surface treatment agents exemplified for the core wire. The surface treatment agents may be used alone or in combination, and the short fibers may be treated multiple times with the same or different surface treatment agents.

[0099] The first short fibers may be oriented in the width direction of the belt and embedded in the first rubber layer 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 the range of about 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, resulting in a decrease in flexibility.

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

[0102] Examples of the crosslinking agent (first crosslinking agent) include the crosslinking agents exemplified as the crosslinking agent for the cord. 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 (magnesium oxide, zinc oxide, etc.) among the above crosslinking agents, and a combination of a metal oxide and a sulfur-based crosslinking agent is particularly preferred.

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

[0104] The co-crosslinking agent (first co-crosslinking agent), including preferred embodiments thereof, can be selected from the co-crosslinking agents exemplified as the co-crosslinking agent for the cord. The proportion of the first co-crosslinking agent is, for example, 0.1 to 10 parts by mass, preferably 0.5 to 8 parts by mass, further preferably 1 to 5 parts by mass, and further preferably 2 to 4 parts by mass, relative to 100 parts by mass of the first rubber component.

[0105] The proportion of the first softener (oils such as naphthenic oil) may be 30 parts by mass or less (e.g., 0 to 30 parts by mass) relative to 100 parts by mass of the first rubber component, converted into solid content, and is, 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 (e.g., 0 to 10 parts by mass) per 100 parts by mass of the first rubber component, calculated as solid content, and is, 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 antioxidant, calculated as solid content, relative to 100 parts by mass of the first rubber component is, for example, 0.5 to 15 parts by mass, preferably 1 to 10 parts by mass, further preferably 2.5 to 7.5 parts by mass, and even more preferably 3 to 7 parts by mass.

[0108] The rubber hardness Hs (Type A) of the first rubber layer can be selected, for example, from a range of about 80 to 100°, and is 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, there is a risk that the resistance to lateral pressure will decrease, and if it is too high, there is a risk that the fit with the pulley groove and flexibility will decrease.

[0109] The tensile strength of the first rubber layer in the belt width direction is, for example, 15 to 50 MPa, preferably 20 to 40 MPa, further preferably 23 to 35 MPa, even more preferably 25 to 30 MPa, and most preferably 26 to 28 MPa. If the tensile strength is too low, there is a risk that the lateral pressure resistance will decrease. Conversely, if the tensile strength is too high, there is a risk that the flexibility will 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 contained in the second crosslinked rubber composition can be selected from the rubber components exemplified as the rubber component for the cord, including preferred embodiments. The second rubber component may be a rubber component different from the rubber component for the cord, but is usually the same type as the rubber component for the cord.

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

[0112] The proportion of the second filler (particularly carbon black) relative to 100 parts by mass of the second rubber component is, for example, 5 to 100 parts by mass, preferably 10 to 80 parts by mass, further preferably 30 to 70 parts by mass, and even more preferably 40 to 60 parts by mass. 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, including preferred embodiments, can be selected from the fibers exemplified as the first short fibers. The average fiber diameter and average length of the second short fibers, including preferred embodiments, can also be selected from the numerical ranges of the average fiber diameter and average length of the first short fibers.

[0114] From the viewpoint of dispersibility and adhesiveness of the second short fibers in the second crosslinked rubber composition, the second short fibers may be subjected to an adhesion treatment (or surface treatment) by a conventional method. Examples of the surface treatment method include a method of treating with a treatment liquid containing a conventional surface treatment agent. Examples of the surface treatment agent include those exemplified as the surface treatment agent for the core wire. The surface treatment agents may be used alone or in combination, and the short fibers may be treated multiple times with the same or different surface treatment agents.

[0115] The second short fibers may be oriented in the width direction of the belt and embedded in the second rubber layer 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 the range of about 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, resulting in a decrease in flexibility.

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

[0118] Examples of the crosslinking agent (second crosslinking agent) include the crosslinking agents exemplified as the crosslinking agent for the cord. 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 (magnesium oxide, zinc oxide, etc.) among the crosslinking agents, and a combination of a metal oxide and a sulfur-based crosslinking agent is particularly preferred.

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

[0120] The co-crosslinking agent (second co-crosslinking agent), including preferred embodiments, can be selected from the co-crosslinking agents exemplified as the co-crosslinking agent for the cord. The proportion of the second co-crosslinking 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 even more preferably 2 to 4 parts by mass, relative to 100 parts by mass of the second rubber component.

[0121] The proportion of the second softener (oils such as naphthenic oil) may be 30 parts by mass or less (e.g., 0 to 30 parts by mass) per 100 parts by mass of the second rubber component, converted into solid content, and is, 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 (e.g., 0 to 10 parts by mass) per 100 parts by mass of the second rubber component, calculated as solid content, and is, 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 antioxidant, converted into solid content, relative to 100 parts by mass of the second rubber component is, for example, 0.5 to 15 parts by mass, preferably 1 to 10 parts by mass, further preferably 2.5 to 7.5 parts by mass, and even more preferably 3 to 7 parts by mass.

[0124] The rubber hardness Hs (Type A) of the second rubber layer can be selected, for example, from a range of about 80 to 100°, and is 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, there is a risk that the resistance to lateral pressure will decrease, and if it is too high, there is a risk that the fit with the pulley groove and flexibility will decrease.

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

[0126] (Tie band characteristics) The average thickness of the tie band (thickness a in FIG. 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, even more preferably 2 to 4 mm (e.g., 2 to 3 mm), even more preferably 2.5 to 4 mm, and most preferably 2.5 to 3.5 mm. In particular, for ASABE HA type, the average thickness may be 2 to 5 mm, and for ASABE HB type and HC type, the average thickness may be 2.5 to 4 mm (particularly 2.5 to 3.5 mm). If the tie band is too thin, it may be prone to breakage, resulting in reduced durability. If it is too thick, it may be less flexible, resulting in reduced 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 that 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, whereas 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 that 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, whereas if it is too large, the flexibility of the belt may decrease.

[0129] [Wrapped V-belt section] In the combined 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 FIG. 1 (a wrapped V-belt portion having a structure in which the inner peripheral surface and side surfaces of a V-belt main body consisting of a third rubber layer formed on the outer periphery of the belt and a fourth rubber layer laminated on the inner periphery of the third rubber layer and having a rubber hardness Hs lower than that of the third rubber layer are covered with a cover cloth). It may be any wrapped V-belt portion that has a V-belt main body at least the side surfaces of which are covered with a cover cloth, has an endless V-shaped cross section, and is formed by a V-shaped cross section. In the combined V-belt of the present invention, both the left and right side surfaces of the V-shaped cross section (V-shaped side surfaces) are frictional power transmission surfaces. In the V-shaped cross section, the wider side of the belt is the outer periphery, and the narrower side is the inner periphery. The V angle (α1) of the V-shaped side surface relative to the belt thickness direction is, for example, 35 to 45°, preferably 36 to 44°, further preferably 37 to 43°, even more preferably 38 to 42°, and most preferably 39 to 41° (particularly 40°).

[0130] (Cover cloth) In the combined V-belt of the present invention, the V-belt body is preferably one whose outer peripheral surface (the surface that comes into contact with the tie band) is not covered with a cover fabric, and in such a V-belt body, the crosslinked rubber composition is exposed on the outer peripheral surface of the V-belt body, thereby improving the adhesive strength with the second rubber layer of the tie band. Furthermore, a V-belt body in which only the inner peripheral surface and side surfaces are covered with a cover fabric, as shown in Figure 1, is particularly preferred, as it can improve the adhesive strength with the second rubber layer of the tie band and is also excellent in productivity.

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

[0132] Examples of the fibers constituting the fabric include the fibers exemplified as the fibers constituting the core wire. The fibers may be a single yarn made of a single type of fiber, or a composite yarn (such as a blended yarn) made of a combination of two or more types of fibers.

[0133] Among the above fibers, blended yarns of polyester fibers and cellulosic fibers are preferred from the viewpoint of excellent mechanical properties and economic efficiency.

[0134] The polyester fiber may be a polyalkylene arylate fiber. Examples of the polyalkylene arylate fiber include poly(C) fibers such as polyethylene terephthalate (PET) fibers and polyethylene naphthalate (PEN) fibers. 2-4 Alkylene-C 8-14 arylate fibers, etc. These polyester fibers may be used alone or in combination of two or more.

[0135] Cellulose-based fibers include cellulose fibers (cellulose fibers derived from plants, animals, bacteria, etc.) and cellulose derivative fibers. Examples of cellulose fibers include cellulose fibers (pulp fibers) derived from natural plants such as wood pulp (coniferous and hardwood pulp, etc.), bamboo fiber, sugarcane fiber, seed hair fibers (cotton fiber (cotton linter), kapok, etc.), algae fiber (Manila hemp, New Zealand hemp, etc.), animal-derived cellulose fibers such as sea squirt cellulose, bacterial cellulose fiber, and algae cellulose. Examples of cellulose derivative fibers include cellulose ester fibers and regenerated cellulose fibers (rayon, cupra, lyocell, etc.). These cellulose-based fibers can be used alone or in combination. Among these, cotton fiber is preferred.

[0136] The mass ratio of polyester fiber to cellulosic fiber (former / latter) is, for example, 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 constituting 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 fabric) is, for example, 100 to 500 g / m 2 , preferably 200 to 400 g / m 2 , and more preferably 250 to 350 g / m 2 is.

[0139] The average thickness of the fabric (raw fabric) 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] When the fabric (raw fabric) is a woven fabric, the thread density (density of warp and weft threads) of the fabric 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 a single layer or multiple layers (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 fabric having a rubber component attached thereto in order to improve adhesion to the V-belt body. The cover fabric having a rubber component attached thereto may be a fabric that has been subjected to an adhesion treatment, such as a treatment of soaking (immersing) the fabric in a rubber cement prepared by dissolving a rubber composition in a solvent, or a treatment of rubbing (rubbing) a solid rubber composition into the fabric. The adhesion treatment may be performed on at least one surface of the fabric, and it is preferable to treat at least the surface that comes into contact with the V-belt body.

[0143] The rubber component (rubber component for cover fabric) constituting the rubber composition (rubber composition for cover fabric) to be attached to the cover fabric can be selected from the rubber components exemplified as the rubber component for the cord, 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 the fillers exemplified as the filler for the cord. Among the above fillers, carbon black is preferred. The carbon black, including preferred embodiments thereof, can be selected from the carbon blacks exemplified as the filler for the cord.

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

[0146] The rubber composition for the cover fabric may further contain other additives exemplified in the section on the crosslinked rubber composition for the cord, if necessary.

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

[0148] The proportion of the crosslinking agent for the cover fabric, in terms of solid content, 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 even more preferably 7 to 13 parts by mass, per 100 parts by mass of the rubber component for the cover fabric, depending on the type of crosslinking agent and rubber component.

[0149] The proportion of the co-crosslinking agent (co-crosslinking agent for the cover fabric) such as bismaleimides, calculated as solid content, is, 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 the cover fabric, and it is more preferable that no co-crosslinking agent is contained.

[0150] The proportion of the crosslinking accelerator (crosslinking accelerator for the cover fabric) may be 15 parts by mass or less (e.g., 0 to 15 parts by mass) relative to 100 parts by mass of the rubber component for the cover fabric, calculated as solid content, and is, for example, 0.1 to 10 parts by mass, preferably 0.2 to 5 parts by mass, further preferably 0.3 to 3 parts by mass, and further preferably 0.5 to 1.5 parts by mass.

[0151] The proportion of the cover fabric processing agent or processing aid (such as stearic acid) may be 10 parts by mass or less (e.g., 0 to 10 parts by mass) per 100 parts by mass of the cover fabric rubber component, calculated as solid content, and is, 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 antioxidant for the cover fabric, calculated as solid content, relative to 100 parts by mass of the rubber component for the cover fabric is, 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 even more preferably 3 to 7 parts by mass.

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

[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 applied to the outer cover 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 (in the case of a multi-layer structure, the average thickness of each layer) 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 formed with a rubber layer made of a cross-linked rubber composition. It is not limited to the two-layer V-belt body shown in FIG. 1 , but may also be a single-layer V-belt body or a V-belt body having a laminated structure of three or more layers. Among these, a V-belt body having a laminated structure of two or more layers is preferred because it can achieve both lateral pressure resistance and flexibility. A V-belt body including a high-hardness (high-rigidity) third rubber layer formed on the outer periphery of the belt in contact with the tie band and a fourth rubber layer having a lower rubber hardness Hs than the third rubber layer, or a single-layer V-belt body, is more preferred. A two-layer V-belt body consisting of the third rubber layer and the fourth rubber layer is particularly preferred. A two-layer V-belt body consisting of the third rubber layer and the fourth rubber layer can achieve higher lateral pressure resistance than a single-layer V-belt body by disposing the third rubber layer, which has a higher hardness than the fourth rubber layer, on the outer periphery of the fourth rubber layer, which has a hardness similar to that of the single-layer V-belt body.

[0157] The third rubber layer is formed of a third crosslinked rubber composition containing a third rubber component. The ranges of components and proportions of the third filler, third short fibers, etc., and the rubber hardness and tensile strength of the third crosslinked rubber composition, including preferred embodiments, can be selected from the ranges of components and proportions of the second filler, second short fibers, etc., of the second crosslinked rubber composition. From the standpoints of interlayer adhesion with the tie band and productivity, the third crosslinked rubber composition is preferably the same or identical to the second crosslinked rubber composition.

[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, for example, from a range of about 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, there is a risk that the resistance to lateral pressure will decrease, and if it is too high, there is a risk that the fit with the pulley groove and flexibility will decrease.

[0159] The tensile strength of the third rubber layer is higher than that of the fourth rubber layer, and is, for example, 15 to 50 MPa, preferably 20 to 45 MPa, further preferably 23 to 40 MPa, even 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, there is a risk of reduced lateral pressure resistance. Conversely, if the tensile strength is too high, there is a risk of reduced flexibility.

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

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

[0162] The proportion of the fourth filler (particularly carbon black) relative to 100 parts by mass of the fourth rubber component is, for example, 5 to 100 parts by mass, preferably 10 to 80 parts by mass, further preferably 15 to 50 parts by mass, and even more preferably 20 to 40 parts by mass. 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 cross-linked rubber composition may also further contain other additives exemplified in the section on the cross-linked rubber composition for cords, if necessary.

[0164] Examples of the crosslinking agent (fourth crosslinking agent) include the crosslinking agents exemplified for the core wire. The crosslinking agents can be used alone or in combination of two or more. When the rubber component is chloroprene rubber, the crosslinking agent for the cover fabric is preferably a crosslinking agent containing a metal oxide (magnesium oxide, zinc oxide, etc.) among the crosslinking agents.

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

[0166] The proportion of the co-crosslinking agent (fourth co-crosslinking agent) such as bismaleimides is, 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, converted into solid content, and it is more preferable that no co-crosslinking agent is contained.

[0167] The proportion of the crosslinking accelerator (fourth crosslinking accelerator), converted into solid content, may be 15 parts by mass or less (e.g., 0 to 15 parts by mass) relative to 100 parts by mass of the fourth rubber component, and is, for example, 0.1 to 10 parts by mass, preferably 0.2 to 5 parts by mass, further preferably 0.3 to 3 parts by mass, and further 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 (e.g., 0 to 10 parts by mass) per 100 parts by mass of the fourth rubber component, calculated as solid content, and is, 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 antioxidant, calculated as solid content, relative to 100 parts by mass of the fourth rubber component is, for example, 0.5 to 15 parts by mass, preferably 1 to 10 parts by mass, further preferably 2.5 to 7.5 parts by mass, and even more preferably 3 to 7 parts by mass.

[0170] The proportion of the fourth plasticizer, calculated as solid content, relative to 100 parts by mass of the fourth rubber component is, for example, 3 to 50 parts by mass, preferably 5 to 40 parts by mass, further preferably 10 to 30 parts by mass, and further preferably 15 to 25 parts by mass.

[0171] The fourth rubber layer has a rubber hardness Hs (Type A) 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)] may be, for example, 1° or more (particularly 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° (particularly 15 to 17°). If the difference in rubber hardness Hs is too small, flexibility may be reduced.

[0172] The rubber hardness Hs (Type A) of the fourth rubber layer can be selected, for example, from a range of about 60 to 90°, and is 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, there is a risk that the resistance to lateral pressure will decrease, and if it is too high, there is a risk that the fit with the pulley groove and flexibility will decrease.

[0173] The tensile strength of the fourth rubber layer is lower than that of the third rubber layer, and 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, there is a risk of reduced lateral pressure resistance. Conversely, if the tensile strength is too high, there is a risk of reduced flexibility.

[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, still 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, lateral pressure resistance may decrease, and if it is too large, flexibility may decrease.

[0175] When the V-belt main 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. The other rubber layers may be laminated on either the outer or inner circumferential surface of the fourth rubber layer. The average thickness of the other rubber layers (the total thickness when multiple other rubber layers are present) may be, for example, 30% or less of the average thickness of the V-belt main body, preferably 10% or less, and more preferably 5% or less. In other words, the V-belt main body preferably includes the third and fourth rubber layers as main layers. The combined average thickness of the third and fourth rubber layers may be, for example, 70% or more of the average thickness of the V-belt main body, preferably 90% or more, and more preferably 95% or more. It is particularly preferable that the V-belt main body consists of only the third and fourth rubber layers.

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

[0177] (reinforcement layer) To improve productivity of the wrapped-bonded V-belt, 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. When the V-belt body has a laminated structure of three or more rubber layers, a reinforcing layer may be interposed between all the rubber layers, but from the viewpoint of productivity, it is preferable to have one reinforcing layer interposed per V-belt body. The reinforcing layer is preferably disposed near the midpoint of the belt body in the thickness direction or between the midpoint and the outer peripheral surface of the belt body.

[0178] Fig. 4 shows a schematic partial cross-sectional perspective view of another example of a combined V-belt of the present invention, in which a reinforcing layer is interposed between the third and fourth rubber layers. This example is the same as the combined V-belt shown in Fig. 1, except that a reinforcing layer 5c made of a fiber structure is interposed between the third and fourth rubber layers 5a and 5b.

[0179] As the fiber structure constituting the reinforcing layer, conventional fabrics can be used, such as woven blinds, woven fabrics, knitted fabrics, nets (network structures or meshes), etc. Among these, woven fabrics or fabrics having a weave such as woven blinds or plain weaves are preferred, and woven blinds are particularly preferred, as they can simultaneously suppress breakage and provide flexibility (flexibility) in the belt longitudinal direction, and also have an excellent balance with productivity.

[0180] Among the various types of woven tire fabrics, those containing a plurality of filaments extending in the belt width direction are preferred because they can further improve resistance to tensile forces acting in the belt width direction. It is particularly preferred to use a woven tire fabric containing a plurality of first filaments (filament bodies) extending in the belt width direction and a plurality of second filaments having a lower thread density (arrangement density) than the first filaments and extending in a direction intersecting the belt width direction.

[0181] In the present application, the filaments extending in the belt width direction refer to filaments extending substantially parallel to the belt width direction. The term "substantially parallel" means that the angle between the extension direction of the filaments and the belt width direction is, for example, about 10° or less (e.g., 0 to 5°), preferably 3° or less (e.g., 0 to 1°, particularly approximately 0°).

[0182] The thread density of the first filament (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, even more preferably 80 to 180 threads / 5 cm, even more preferably 100 to 150 threads / 5 cm, and most preferably 110 to 130 threads / 5 cm.

[0183] The thread density of the second filament (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, even more preferably 2 to 8 threads / 5 cm, even 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 filaments include the fibers exemplified as the fibers constituting the first staple fibers of the first rubber layer. Of the staple fibers, polyester fibers and polyamide fibers are preferred for the first filaments, with aliphatic polyamide fibers such as polyamide 66 fibers being particularly preferred. Cellulose fibers are preferred for the second filaments, with cotton fibers being particularly preferred.

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

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

[0187] The fiber structure may be subjected to a conventional adhesive treatment or surface treatment (e.g., treatment with a treatment liquid containing an adhesive component) to improve adhesion to a rubber component (crosslinked rubber composition), etc. The adhesive 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 thickness of the fiber structure is too thin, the effect of improving the productivity of the wrapped coupled V-belt may be reduced. If the thickness of the fiber structure is too thick, the flexibility of the belt may be reduced.

[0189] In order to improve the adhesion between the fiber structure and the rubber layer, the reinforcing layer is preferably configured such that the fiber structure is embedded (sandwiched) between the rubber components (reinforcing layer sandwiched rubber), in which case the fiber structure is embedded in the crosslinked rubber composition.

[0190] The cross-linked rubber composition constituting the reinforcing layer is not particularly limited, but is preferably selected from the cross-linked rubber compositions exemplified as the cross-linked rubber composition for the core wire that forms the adhesive rubber layer, and preferred embodiments can also be selected from the preferred embodiments of the cross-linked rubber composition for the core wire.

[0191] The reinforcing layer can be used alone (single layer) or in combination of two or more types (laminated structure). Considering productivity, 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 bonded V-belt may be reduced. Conversely, if the reinforcing layer is too thick, the flexibility of the belt may be reduced.

[0193] (Characteristics of the wrapped V-belt) The average thickness of the wrapped V-belt portion 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 portion is too small, the area of ​​the frictional power transmission surface becomes small, and there is a risk of a decrease in power transmission efficiency.

[0194] The average thickness of the wrapped V-belt portion is, for example, 60 to 90%, preferably 65 to 90%, further preferably 70 to 90%, and even more preferably 75 to 90% of the average thickness of the entire combined V-belt. If the thickness ratio of the wrapped V-belt portion (b / total thickness in Figure 3) is too small, the area of ​​the frictional power transmission surface will be small, which may result in a decrease in power transmission efficiency, and if it is too large, there is a risk of a decrease in durability.

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

[0196] First, the thickness of the "whole joined V-belt" and the "wrapped V-belt portion" are measured in an image of the cross section of the joined V-belt taken with a microscope. Next, one measurement point is selected for each wrapped V-belt portion aligned in the width direction of the joined V-belt, and the thickness of the "whole joined V-belt" and the "wrapped V-belt portion" are measured at each measurement point. The average thickness is then calculated from the thicknesses at each measurement point. In other words, for a joined V-belt made up of three connected wrapped V-belt portions, for example, the average value of the three points is measured.

[0197] When the V-belt main body includes a third rubber layer and a fourth rubber layer, the average thickness of the third rubber layer can be selected, for example, from the range of about 10 to 70% of the average thickness of the V-belt main body, and is 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, there is a risk that the lateral pressure resistance will decrease, and if it is too large, there is a risk that the flexibility will decrease.

[0198] [Characteristics of Wrapped Connected V-Belts] The average thickness (height in the belt thickness direction or total thickness in Figure 3) of the wrapped coupled 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 coupled V-belt is too small, the area of ​​the frictional power transmission surface will be small, which may result in a decrease in power transmission capacity.

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

[0200] In the wrapped joined V-belt of the present invention, the pitch of the wrapped V-belt portion (average distance between the centers 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] <Manufacturing method of wrapped bonded V-belt> The wrapped bonded V-belt of the present invention includes a wrapped V-belt portion precursor preparation step of covering a V-belt main body precursor with a cover cloth, and a connecting step of connecting multiple wrapped V-belt portion precursors obtained in the above step with a tie band precursor including a core wire.

[0202] [Wrapped V-belt precursor manufacturing process] In the wrapped V-belt portion precursor manufacturing process, the V-belt main body precursor obtained by rolling is cut and wound around a mantle in a winding process, and then cut to a predetermined belt width in a cutting process.

[0203] FIG. 5 is a schematic diagram illustrating the cutting process of a V-belt main body precursor consisting of the third and fourth rubber layers. Specifically, FIG. 5(a) shows a schematic perspective view, and FIG. 5(b) shows a schematic enlarged partial cross-sectional view of FIG. 5(a). As shown in FIG. 5, a laminate of uncrosslinked third rubber layer sheets 7a and fourth rubber layer sheets 7b obtained by rolling is cut and wrapped around a mantle. The resulting annular laminate 7 is then subjected to a cutting process, where it is cut (sliced) to a predetermined core width (belt width) on the mantle to produce a core (cut annular laminate) 8 consisting of third rubber layer sheets 8a and fourth rubber layer sheets 8b. If a reinforcing layer is to be interposed between the third and fourth rubber layers, a reinforcing layer precursor is wrapped between the third and fourth rubber layer sheets.

[0204] The annular laminate cut to a predetermined belt width is subjected to skiving and cover winding. Fig. 6 is a schematic diagram illustrating the skiving and cover winding processes of the core 8 obtained in Fig. 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 on the side and bottom surfaces (inner peripheral surfaces) of the V-belt body precursor 9 with a cover cloth precursor 11 (cover winding process), thereby obtaining a wrapped V-belt portion precursor 10.

[0205] [Connection process] In the connecting step, the multiple wrapped V-belt portion precursors obtained in the previous step are connected with a tie band precursor including a cord, and this step will be described with reference to FIGS.

[0206] 7, in a connecting device 20 for connecting wrapped V-belt portion precursors, an uncrosslinked wrapped V-belt portion precursor (a set of multiple wrapped V-belt portion precursors) 10 held in a state of being wound around a pair of pulleys 23a, 23b is sandwiched between the pair of pulleys 23a, 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 platen 24 for crosslinking the wrapped V-belt portion precursor 10 is disposed between the inner circumferential mold 21a and the inner circumferential mold 22a.

[0207] FIG. 8 is a schematic cross-sectional view (cross-sectional view in the belt width direction) showing the state in which the wrapped V-belt portion precursors are fitted into the press mold in the connecting step. The multiple wrapped V-belt portion precursors 10 obtained in the wrapped V-belt portion precursor manufacturing step are fitted into grooves (grooves with an inverted trapezoidal cross section corresponding to the wrapped V-belt portions lined up in the belt width direction) formed in a cylindrical or annular inner mold (cross-linking mold) 21a.

[0208] 9 to 11 are schematic cross-sectional views illustrating the process of winding a tie band precursor onto a wrapped V-belt portion precursor in the connecting step.

[0209] As shown in FIG. 9, in the connecting process, first, the wrapped V-belt portion precursors 10 are fitted into the grooves of the inner circumferential side mold 21a (or inner circumferential side mold 22a, not shown) and arranged at predetermined intervals in the belt width direction. An uncrosslinked second rubber layer sheet 12 is then wound around the wrapped V-belt portion precursors 10 so as to bridge the outer surfaces of the wrapped V-belt portion precursors 10, and an uncrosslinked inner adhesive rubber layer sheet 13 is then wound on top of the second rubber layer sheet 12.

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

[0211] 12 is a schematic cross-sectional view illustrating the crosslinking treatment of the wrapped-bonded V-belt precursor. The wrapped-bonded V-belt precursor, which is made up of the obtained wrapped V-belt portion precursor and tie-band precursor, is subjected to a crosslinking treatment (vulcanization treatment) in which the outer mold 21b is disposed on the first rubber layer sheet 16, and the wrapped-bonded V-belt precursor is sandwiched between the inner mold 21a and the outer mold 21b and pressurized and heated.

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

[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 compounded in the rubber composition are as follows:

[0215] Chloroprene rubber: Denka Co., Ltd. "PM-40" Magnesium oxide: Kyowa Mag 30 manufactured by Kyowa Chemical Industry Co., Ltd. Stearic acid: "Camellia Stearate" manufactured by NOF Corporation Anti-aging agent (octyldiphenylamine): "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 m 2 / g Plasticizer: ADEKA Corporation "RS-700" Crosslinking accelerator: "Noccela TT" manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Zinc oxide: "Zinc oxide type 3" manufactured by Seido Chemical Industry Co., Ltd. Naphthenic oil: Idemitsu Kosan Co., Ltd. "NS-900" Co-crosslinking agent (N,N'-m-phenylenedimaleimide): "Valnoc PM" manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Aramid staple fiber: Teijin Co., Ltd.'s "Conex staple fiber," average fiber length 3 mm, average fiber diameter 14 μm, staple fiber with a solid adhesion rate of 6 mass% that was adhesively treated with RFL liquid (resorcinol 2.6 parts, 37% formalin 1.4 parts, vinylpyridine-styrene-butadiene copolymer latex (Zeon Corporation) 17.2 parts, water 78.8 parts). Sulfur (powdered sulfur): manufactured by Bigen Chemical Co., Ltd.

[0216] (Core 1) Two 1670 dtex aramid fiber bundles were pulled together and twisted in the S direction with a twist factor of 3.0 to produce a first twisted yarn, and three of these first twisted yarns were pulled together and twisted in the Z direction with a twist factor of 3.0 to produce a twisted cord (plied yarn) with a total fineness of 10020 dtex and a diameter of 1.19 mm, which was then adhesively treated and used as the core wire.

[0217] (core 2) Three aramid fiber bundles of 1670 dtex (1000 filaments) were pulled together and twisted in the S direction with a twist factor of 3.0 to produce a first twisted yarn. Five of these first twisted yarns were pulled together and twisted in the Z direction with a twist factor of 3.0 to produce a twisted cord (plied yarn) with a total fineness of 25050 dtex (15000 filaments) and a diameter of 1.9 mm, which was then adhesively treated and used as the core wire.

[0218] [Rubber composition for adhesive rubber layer and friction rubber] Rubber composition A having the formulation shown in Table 2 was kneaded in a Banbury mixer, and this kneaded rubber was passed through a calendar roll to form an uncrosslinked rolled rubber sheet of a predetermined thickness, which was used to prepare a sheet for an adhesive rubber layer. Rubber composition B shown in Table 2 was also kneaded in a Banbury mixer to prepare a bulk uncrosslinked rubber composition for friction. Furthermore, the hardness and tensile strength of the crosslinked products of each rubber composition were measured, and the results are also shown in Table 2. The uncrosslinked rolled rubber sheet formed from rubber composition A was used not only as a sheet for an adhesive rubber layer, but also as a reinforcing layer precursor and a connecting reinforcing layer precursor for tie bands.

[0219] [Table 2]

[0220] [Rubber Compositions for First to Fourth Rubber Layers] Rubber compositions C to E having the formulations shown in Table 3 were kneaded in a Banbury mixer, and the kneaded rubber was passed through a calendar roll to form uncrosslinked rolled rubber sheets of a predetermined thickness, to prepare sheets for the first to fourth rubber layers, respectively. Furthermore, the hardness and tensile strength of the crosslinked products 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 160°C, 2.5 MPa, and 30 minutes to produce a crosslinked rubber sheet (100 mm x 100 mm x 2 mm thick). Three of the resulting crosslinked rubber sheets were stacked together to form a laminate, which was used as a sample. The rubber hardness Hs (Type A) of the crosslinked rubber sheet was measured using a Type A durometer in accordance with the spring durometer hardness test specified in JIS K 6253 (2012) (Vulcanized rubber and thermoplastic rubber - Determination of hardness). For the friction block uncrosslinked rubber composition B, a test specimen was sampled from the block rubber and passed 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 (size 5) test specimens were prepared according to JIS K 6251 (2017). For samples containing short fibers, dumbbell-shaped test specimens were prepared so that the orientation direction of the short fibers (grain direction) was the tensile direction. Both ends of the test specimen were gripped with chucks (gripping tools), and the test specimen was pulled at a speed of 500 mm / min until it broke. The maximum tensile force recorded when the specimen was pulled by the initial cross-sectional area of ​​the test specimen was used as the tensile strength (T).

[0224] [Reinforcing layer precursor (treated blind)] A blind was subjected to adhesive treatment and rubber sheet lamination treatment to prepare a reinforcing layer precursor. Specifically, a blind-like fabric was woven using 470 dtex single-twisted nylon 66 cord (wire diameter 0.22 mm) as the warp and 40 count cotton yarn (wire diameter 0.1 mm) as the weft at a warp density of 120 / 50 mm and a weft density of 5 / 50 mm. The fabric was immersed in RFL liquid (a mixture of 2.6 parts by mass of resorcinol, 1.4 parts by mass of 37% by mass 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 laminated with uncrosslinked rubber sheets of rubber composition A on both sides to prepare a treated 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 produce a cover fabric precursor. Specifically, a 20s / 3 (20 count, 3-ply) blend of polyester fiber and cotton in a mass ratio of 50 / 50 was used as the warp and weft yarns, and the fabric was plain woven with a warp density of 75 / 50mm and a weft density of 75 / 50mm to produce a fabric with a basis weight of 280g / m. 2 The canvas was immersed in RFL liquid (a mixture of 2.6 parts by mass of resorcinol, 1.4 parts by mass of 37% by mass 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 wide-angle treatment so that the angle between the warp and weft yarns was 120 degrees. The front and back surfaces of the obtained wide-angle canvas were treated with a friction treatment in which the rubber composition B in Table 2 was rubbed into them to produce a rubberized woven fabric (basis weight approximately 500 g / m2). 2 A thickness of approximately 0.6 mm was prepared.

[0226] [Fabric precursor for tie bands (woven fabric with elastic)] The woven fabric was subjected to adhesive and friction treatments to produce a fabric precursor for tie bands. Specifically, a 10s / 3 (10 count, 3-ply) blend of polyester fiber and cotton in a mass ratio of 50 / 50 was used as the warp and weft yarns, and the fabric was plain woven with a warp density of 44 / 50 mm and a weft density of 44 / 50 mm to produce a fabric weight of 280 g / m. 2The canvas was immersed in RFL liquid (a mixture of 2.6 parts by mass of resorcinol, 1.4 parts by mass of 37% by mass 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 subjected to wide-angle treatment so that the angle between the warp and weft yarns was 120 degrees. The front and back of the obtained wide-angle canvas were treated (friction) by rubbing the rubber composition B in Table 2 into them, and then rubberized woven fabric (basis weight approximately 1050 g / m2) was produced. 2 A thickness of approximately 1.0 mm was prepared.

[0227] [Precursor of connecting reinforcement layer for tie bands (treated blinds)] A blind was subjected to adhesive treatment and rubber sheet lamination treatment to prepare a tie band connecting reinforcing layer precursor. Specifically, a blind-like fabric was woven using 470 dtex single-twisted nylon 66 warp cords (wire diameter 0.22 mm) and 40-count cotton weft yarns (wire diameter 0.1 mm) at a warp density of 120 / 50 mm and a weft density of 5 / 50 mm. The fabric was immersed in RFL liquid (a mixture of 2.6 parts by mass of resorcinol, 1.4 parts by mass of 37% by mass 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 laminated with uncrosslinked rubber sheets of rubber composition A on both sides to prepare a treated blind (thickness approximately 1.5 mm).

[0228] [Durability test] (Testing machine) For the test, a multi-axle running test machine with a multi-axle layout shown in Figure 14 was used.

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

[0230] [Table 4]

[0231] (Test Method) Each test specimen of the combined V-belt was run under the conditions shown in Table 5 with the loads shown in Table 6 applied, and the belt was visually inspected over time to check for damage and evaluated according to the following criteria. Note that the load during running was measured under various loads applied to the driven pulley Dn2 and driven pulley Dn3 as shown in Table 6.

[0232] [Table 5]

[0233] [Table 6]

[0234] (Durability driving criteria) a: 240 hours completed, no cracks, peeling or other abnormalities were found b: After 240 hours of running, some cracks and peeling were observed (but this did not affect performance). c: An abnormality such as cracking or peeling was found during the run and the car did not complete the race.

[0235] [Side shake test] (Testing machine) For the test, a biaxial running test machine with a biaxial layout shown in Figure 15(a) was used.

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

[0237] [Table 7]

[0238] (Test Method) Each test piece of the combined V-belt was run around under the conditions shown in Table 8, and the amount of lateral deflection while the belt was running was measured using a laser displacement meter ("Fiber Sensor" manufactured by Keyence Corporation) 44 that measures in the belt thickness direction and a laser displacement meter 45 that measures in the belt width direction, as shown in Figure 15(b), for the combined belt 43. The belt was rotated two times, and the average value of the lateral deflection on the third rotation was measured.

[0239] For comparison, Figure 16 shows data on the lateral runout of 33 samples of a conventional wrapped coupled V-belt (the coupled V-belt obtained in Comparative Example 2) in which the ASABE HB-type wrapped V-belt portion containing a core wire is connected with a tie band that does not contain a core wire. Figure 17 shows the change in amplitude over one belt revolution for sample Belt No. 2, which had a lateral runout of 5.8 mm. The lateral runout test was evaluated according to the following criteria. Evaluations a and b were considered pass levels.

[0240] [Table 8]

[0241] (Horizontal shake judgment criteria) a:3mm or less b: Over 3mm and 5mm or less c: More than 5mm

[0242] [Overall Judgment] The criteria for the overall evaluation (ranking) of a combined V-belt that can solve this problem were determined based on the results of the two evaluation items (running durability test and lateral vibration test) and were shown in Table 9, with a rank of C or higher being considered a pass.

[0243] [Table 9]

[0244] (Comparative Example 1) (Preparation of Uncrosslinked Rubber Belt) An uncrosslinked fourth rubber layer sheet, a third rubber layer sheet, and an adhesive rubber layer sheet were wound in this order around the outer periphery of a mantle (cylindrical drum), a core wire (core wire 1) was spirally wound around the outer periphery of the uncrosslinked fourth rubber layer sheet, and an adhesive rubber layer sheet and a third rubber layer sheet were wound in this order around the outer periphery of the uncrosslinked fourth rubber layer sheet to form a cylindrical uncrosslinked sleeve in which the uncrosslinked rubber layers and the core wires were laminated. The obtained uncrosslinked sleeve was cut circumferentially while placed on the outer periphery of the mantle to form an annular core (uncrosslinked rubber belt). The short fibers in the third rubber layer sheet were arranged so as to be approximately parallel to the belt width direction.

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

[0246] (Preparation of combined V-belt (connecting process)) Next, the multiple uncrosslinked wrapped V-belt sections containing cords obtained in the above process were connected with a tie band precursor that did not contain cords. Specifically, the uncrosslinked wrapped V-belt sections were fitted into the grooves of the inner mold, and a tie band connection reinforcement layer precursor (treated tire) and a tie band fabric precursor (rubber-coated woven fabric) were wound in this order so as to bridge the outer surfaces of six uncrosslinked wrapped V-belt sections arranged at predetermined intervals in the belt width direction, thereby producing a tie band precursor that was a laminate of the tie band connection reinforcement layer precursor and the tie band fabric precursor. The treated tire was arranged so that the longitudinal direction of the warp yarns was approximately parallel to the belt width direction and the longitudinal direction of the weft yarns was approximately parallel to the belt circumferential direction.

[0247] The tie band precursor and six uncrosslinked wrapped V-belt portions thus set were sandwiched between the inner and outer molds, pressurized to 1.2 MPa, and subjected to a crosslinking molding process (vulcanization process) at a heating temperature of 160°C to produce a crosslinked belt in which the six wrapped V-belt portions were connected and bonded with tie bands.

[0248] The resulting crosslinked belt was cut to produce a wrapped bonded V-belt with three wrapped V-belt segments. The resulting wrapped bonded V-belt was an ASABE HA-type bonded V-belt (belt length 10196 mm, V-belt thickness 8.04 mm, tie band thickness 2.0 mm). A wrapped bonded V-belt with seven wrapped V-belt segments was also produced using the same method.

[0249] Example 1 (Preparation of Uncrosslinked Rubber Belt) An uncrosslinked fourth rubber layer sheet, a reinforcing layer precursor (treated tire), and a third rubber layer sheet were wound around the outer circumferential surface of a mantle (cylindrical drum) in that order to form a cylindrical uncrosslinked sleeve in which the uncrosslinked rubber layer and the reinforcing layer precursor were laminated. The obtained uncrosslinked sleeve was cut circumferentially while positioned on the outer periphery of the mantle to form a circular core (uncrosslinked rubber belt). The short fibers in the third rubber layer sheet were arranged approximately parallel to the belt width direction, and the warp threads of the treated tire were arranged approximately parallel to the belt width direction.

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

[0251] (Preparation of combined V-belt (connecting process)) Next, the multiple uncrosslinked wrapped V-belt portions obtained in the above step were fitted into the grooves of the inner peripheral mold, and the second rubber layer sheet and the adhesive rubber layer sheet were wound in this order so as to bridge the outer peripheries of the six uncrosslinked wrapped V-belt portions arranged at predetermined intervals in the belt width direction, and a core wire (core wire 1) was spirally wound around the outer periphery of the second rubber layer sheet, and then the adhesive rubber layer sheet and the first rubber layer sheet were wound in this order around the outer periphery of the second rubber layer sheet to form a tie band precursor. The short fibers in the first rubber layer sheet and the second rubber layer sheet were arranged so as to be approximately parallel to the belt width direction, and the treated blinds were arranged so that the longitudinal direction of the warp yarns was approximately parallel to the belt width direction and the longitudinal direction of the weft yarns was approximately parallel to the belt circumferential direction.

[0252] The tie band precursor and six uncrosslinked wrapped V-belt portions thus set were sandwiched between the inner and outer molds, pressurized to 1.2 MPa, and subjected to a crosslinking molding process (vulcanization process) at a heating temperature of 160°C to produce a crosslinked belt in which the six wrapped V-belt portions were connected and bonded with tie bands.

[0253] The resulting crosslinked belt was cut to produce 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 thickness 8.04 mm, tie band thickness 2.0 mm). The first rubber layer thickness 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 with seven wrapped V-belt sections was also produced using the same method.

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

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

[0256] Table 10 shows the evaluation results of the durability running test and the lateral vibration test for the combined 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, the combined V-belt of Comparative Example 1, in which the core wires were arranged in the wrapped V-belt portion, was rated b for endurance running, but the amount of lateral deflection was large, earning it a c (fail), resulting in an overall rating of D. In contrast, the combined V-belts of Examples 1 to 3, in which the core wires were arranged within the tie bands, were rated b for endurance running, but the amount of lateral deflection was reduced to the level of a or b (pass), resulting in an overall rating of B.

[0259] (Comparative Example 2) An ASABE HB-type combined V-belt (belt length 10196 mm, V-belt 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-type and core wire 2 was used as the core wire.

[0260] Example 4 Except for the fact that the wrapped V-belt portion was an HB type, an ASABE HB type bonded 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. The first rubber layer thickness 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 3.7 mm, and the fourth rubber layer thickness was 5.84 mm.

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

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

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

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

[0265] [Table 11]

[0266] As is clear from the results in Table 11, the combined V-belt of Comparative Example 2, in which the core wires were arranged in the wrapped V-belt portion, was rated b for endurance running, but the amount of lateral runout was large, earning it a rating of c (fail), resulting in an overall rating of D. In contrast, the combined V-belts of Examples 4 to 6, in which the core wires were arranged within the tie bands, were rated a or b for endurance running, but the amount of lateral runout improved to the level of a (pass), resulting in an overall rating of A or B. For the combined V-belt of Example 7, when the tie band was increased to 8.8 mm, the flexibility decreased, resulting in a shorter endurance running life. Therefore, the amount of lateral runout was rated b, the endurance running was rated c, and the overall rating was C.

[0267] (Comparative Example 3) An ASABE HC-type combined V-belt (belt length 10196 mm, V-belt thickness 14.84 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 HC-type and core wire 2 was used as the core wire.

[0268] Example 8 Except for the fact that the wrapped V-belt portion was an HC type, an ASABE HC type combined V-belt (belt length 10196 mm, V-belt portion thickness 14.84 mm, tie band thickness 2.0 mm) was produced in the same manner as in Example 1. The first rubber layer thickness 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 5.8 mm, and the fourth rubber layer thickness was 7.84 mm.

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

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

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

[0272] [Table 12]

[0273] As is clear from the results in Table 12, the combined V-belt of Comparative Example 3, in which the core wires were arranged in the wrapped V-belt portion, was rated b for endurance running, but the amount of lateral deflection was large, earning it a c (fail), resulting in an overall rating of D. In contrast, the combined V-belts of Examples 8 to 10, in which the core wires were arranged within the tie bands, were rated a or b for endurance running, but the amount of lateral deflection was reduced to the level of a or b (pass), resulting in an overall rating of A or B.

[0274] From the above results, it was found that the configuration of the present invention reduces the lateral vibration (or twist) of the combined V-belt regardless of the scale of the combined V-belt, and improves the durability against belt breakage and rotational breakage. [Industrial Applicability]

[0275] The wrapped coupled 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 planters, and mowers, but because it has excellent lateral pressure resistance, it can be suitably used in high-load machinery used in high-load, long-span layouts. Examples of such high-load machinery include large agricultural machinery used in Europe and the United States, such as cultivators, vegetable transplanters, transplanters, binders, combine harvesters, vegetable harvesters, threshers, bean cutters, corn harvesters, potato harvesters, and beet harvesters. [Explanation of symbols]

[0276] 1...Combined 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...Tie band V...Wrapped V-belt section

Claims

1. A combined V-belt including a plurality of wrapped V-belt portions arranged in a belt width direction and a tie band for connecting these wrapped V-belt portions, The wrapped V-belt portion is formed of a V-belt body and a cover fabric that covers at least the side surface of the V-belt body, and A bonded V-belt, wherein the tie band includes a core wire.

2. 2. The bonded V-belt of claim 1, wherein said tie band includes an adhesive rubber layer containing said cords.

3. 3. The joined V-belt according to claim 1, wherein the tie band includes a first rubber layer formed on the outer circumferential side of the adhesive rubber layer, and a second rubber layer formed between the adhesive rubber layer and the wrapped V-belt portion.

4. 4. The combined V-belt according to claim 1, wherein the V-belt body includes a third rubber layer formed on the outer circumferential side of the belt, and a fourth rubber layer having a rubber hardness Hs (Type A) lower than that of the third rubber layer.

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

6. 6. The combined V-belt according to claim 1, wherein the cover fabric does not cover the outer peripheral surface of the V-belt body.

7. 7. The combined V-belt according to claim 1, wherein the average thickness of the wrapped V-belt portion is 60 to 90% of the average thickness of the entire combined V-belt.

8. The combined V-belt according to any one of claims 1 to 7, wherein the belt length is 3000 mm or more.

9. 9. The method for manufacturing a joined V-belt according to claim 1, further comprising: a wrapped V-belt portion precursor manufacturing step of covering a V-belt main body precursor with a cover cloth; and a connecting step of connecting a plurality of wrapped V-belt portion precursors obtained in the above step with a tie band precursor including a core wire.

10. A belt transmission mechanism comprising the combined V-belt according to any one of claims 1 to 8 and a pulley.

11. 11. The belt transmission mechanism according to claim 10, which is used in an agricultural machine.

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