Wrapped banded v-belt and method for manufacturing same

Abstract

The present invention relates to a wrapped banded V-belt including a plurality of wrapped V-belt portions in which a belt body portion is covered with an outer covering fabric, and a tie band for connecting the plurality of wrapped V-belt portions at the outer peripheral surfaces of the wrapped V-belt portions, wherein the outer peripheral surfaces of the wrapped V-belt portions each have a covered region covered with the outer covering fabric and an uncovered region that is not covered, the covering region is formed on at least one side portion of the outer peripheral surface, and the outer covering fabric that covers the covered region covers the side surfaces of the wrapped V-belt portions.

Description

Wrapped coupled V-belt and method of manufacturing same

[0001] The present invention relates to a wrapped connected V-belt in which a plurality of wrapped V-belt portions are connected in the width direction, and a method for manufacturing the same.

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

[0003] In applications such as agricultural machinery, wrapped V-belts are used, in which the entire belt surface, including the friction transmission surface, is covered with an outer sheath (cover fabric). This is because using a raw-edge V-belt, which is a rubber layer with an exposed friction transmission surface, results in a high coefficient of friction on the transmission surface, which increases stress on the belt and can lead to premature breakage. Furthermore, if the belt becomes entangled with straw, stones, wood, or other debris, the sudden impact on the transmission surface can damage the belt and the entire transmission mechanism. Using a wrapped V-belt reduces the coefficient of friction on the transmission surface, allowing for moderate slippage and mitigating stress and impact on the belt. Furthermore, the transmission surface is protected, making it less susceptible to damage.

[0004] Large agricultural machinery used on large farms in Europe and the United States must transmit enormous amounts of power, necessitating the simultaneous use of multiple V-belts. That is, multiple V-belts must be wound around the pulleys of the belt transmission mechanism in parallel (multiple loops) to rotate and run. 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 result in the inner and outer circumferential sides of the belts being reversed, potentially resulting in an inverted structure (overturning).

[0005] Therefore, when multiple V-belts are run in parallel, a combined belt (combined V-belt) is used, which is configured by connecting multiple annular V-belt portions having the same configuration as the V-belts in the belt width direction. In this combined V-belt, multiple V-belt portions are arranged in parallel and connected or joined by tie bands (connecting members such as fabric). A wrapped V-belt (wrapped V-belt portion) covered with an outer sheath (covering fabric) may be used as the V-belt portion. A typical wrapped combined V-belt in which such wrapped V-belt portions are connected by tie bands (connecting members) is shown in FIG. 1 as a schematic, partially sectional perspective view.

[0006] 1, this wrapped connected V-belt 100 includes two wrapped V-belts (wrapped V-belt portions) 101 arranged in parallel with a gap between them, and the two wrapped V-belts 101 are connected on their outer peripheries by a connecting member (tie band) 102 made of fabric. Each wrapped V-belt 101 is formed of an endless belt main body (belt main body portion) formed by a tension rubber layer 104 on the outer periphery of the belt, a compression rubber layer 103 on the inner periphery of the belt, and a core 105 embedded between the tension rubber layer 104 and the compression rubber layer 103 along the belt longitudinal direction (circumferential direction, direction A in the figure), and an outer cover fabric 106 (woven fabric, knitted fabric, nonwoven fabric, etc.) that covers the periphery of this belt main body over the entire length in the belt circumferential direction. In this example, the core 105 is a core wire (twisted cord) arranged at a predetermined interval in the belt width direction (direction B in the figure), and is in contact with the tension rubber layer 104 and the compression rubber layer 103, and is interposed between the two layers.

[0007] More specifically, a wrapped coupled V-belt is disclosed in Japanese Patent Publication No. 47-34432 (Patent Document 1). A schematic partial cross-sectional view (cross-sectional view perpendicular to the belt length direction) of a conventional wrapped coupled V-belt such as that disclosed in Patent Document 1 is shown in FIG.

[0008] 2 shows a conventional wrapped connected V-belt 111 in which a plurality of (two in the figure) wrapped V-belt portions V arranged in parallel at intervals in the belt width direction (direction B in FIG. 1) are connected by tie bands (connecting members) T. Each wrapped V-belt portion V is composed of an endless belt main body portion having an inverted trapezoidal cross section and extending in the belt length direction (circumferential direction, direction A in FIG. 1), with a laminate structure in which a compression rubber layer 112, a core 113, and a tension rubber layer 114 are laminated in this order from the inner periphery to the outer periphery of the belt, and an outer cover fabric 115 covering the periphery of this belt main body portion. This outer cover fabric 115 is formed from a seamless (single continuous piece of) fabric and covers the entire surface of the belt main body (inner periphery, both side surfaces, and outer periphery). The outer cover fabric 115 is overlapped on the inner periphery to form a two-layer structure.

[0009] However, such a conventional wrapped joined V-belt 111 has a problem in that the wrapped V-belt portion V and the tie band T are easily separated from each other. That is, the entire surface of the belt main body of the wrapped V-belt portion V is covered with the outer cover cloth 115, and the wrapped V-belt portion V is joined or connected to the tie band T via the outer cover cloth 115a that covers the outer peripheral surface side. Therefore, particularly when the tie band T is made of fabric, the fabrics are bonded to each other, making it difficult to join or connect the two with a high adhesive strength.

[0010] As a countermeasure, attempts have been made to improve the adhesive strength between the wrapped V-belt portion and the tie band by exposing the rubber layer from the outer peripheral surface (back surface) of the wrapped V-belt portion. For example, Japanese Patent Application Laid-Open No. 2020-37257 (Patent Document 2) describes that an outer peripheral portion of an unvulcanized rubber belt covered with an outer covering fabric is cut away in the circumferential direction to expose the rubber layer, and in a vulcanization process, a reinforcing fabric (tie band) is placed on the outer peripheral side with multiple unvulcanized rubber belts with exposed rubber layers lined up in parallel and vulcanized, so that the rubber layer exposed from the unvulcanized rubber belt and the reinforcing fabric (tie band) are bonded by vulcanization, thereby improving the adhesive strength compared to conventional methods in which the outer covering fabric and the reinforcing fabric (tie band) are bonded together. Furthermore, Japanese Patent Application Laid-Open Publication No. 2022-102656 (Patent Document 3) describes a configuration in which the upper part of a semi-vulcanized annular laminate structure (a precursor of the belt main body) is buffed with a grindstone or sandpaper to remove the reinforcing fabric (outer covering fabric) to expose the semi-vulcanized laminate structure, tie bands are attached to the uneven surfaces of the buffed multiple annular laminate structures, and the multiple semi-vulcanized annular laminate structures with the attached tie bands are completely vulcanized.

[0011] Japanese Patent Publication No. 47-34432 Japanese Patent Publication No. 2020-37257 Japanese Patent Publication No. 2022-102656

[0012] Fig. 3 shows a schematic partial cross-sectional view of the wrapped coupled V-belts disclosed in Patent Documents 2 and 3. The wrapped coupled V-belt 121 shown in Fig. 3 differs from the wrapped coupled V-belt 111 shown in Fig. 2 in that the outer peripheral surface side of the outer cover cloth 125 that covered the entire surface of the wrapped V-belt portion V has been cut away or removed. That is, the wrapped coupled V-belt 121 is composed of a belt main body portion in which a plurality of wrapped V-belt portions V (two in the figure) are arranged in parallel at intervals in the belt width direction, and in which a compression rubber layer 122, a core 123, and a tension rubber layer 124 are layered in this order from the inner peripheral side to the outer peripheral side of the belt, and a two-tiered outer cover cloth 125 that covers the inner peripheral surface and both side surfaces of the belt main body portion. The two layers of outer cover cloth 125 are overlapped on the inner circumferential side, but before being connected to the tie band T, they were formed from a seamless (single continuous piece of fabric) like the outer cover cloth 115 of the wrapped joined V-belt 111 shown in Fig. 2. That is, the outer cover cloth 125 was originally a single continuous piece of fabric that covered the periphery of the belt main body (the entire surface including the outer circumferential side), but was divided into two pieces by cutting away the outer circumferential side of the wrapped V-belt portion V. Cutting away the outer circumferential side exposes the tension rubber layer 124, and the outer circumferential surface 124a of this exposed tension rubber layer 124 is in direct contact with the tie band T, so it can be bonded or connected to the tie band T with high adhesive strength by the vulcanization process.

[0013] However, the manufacturing methods disclosed in Patent Documents 2 and 3 require a step of exposing the rubber layer from the outer peripheral surface (back surface) side after covering the wrapped V-belt portion with an outer covering fabric, and Patent Document 3 also requires a step of semi-vulcanizing the material, which makes the process complicated and causes material waste, resulting in cost disadvantages.In addition, because the outer covering fabric is completely removed from the back surface of the wrapped V-belt portion, there is a structural disadvantage that the outer covering fabric is easily peeled off from the boundary with the tie band (125a in Figure 3) on the side of the wrapped V-belt portion.

[0014] Therefore, an object of the present invention is to provide a wrapped joined V-belt that can improve the adhesive strength between the wrapped V-belt portion and the tie band and can suppress peeling of the outer covering fabric at the boundary between the side of the wrapped V-belt portion and the tie band, and a method for manufacturing the same.

[0015] Another object of the present invention is to provide a wrapped joined V-belt that can improve the adhesive strength between the wrapped V-belt portion and the tie band and also improve productivity, and a method for manufacturing the same.

[0016] It is still another object of the present invention to provide a wrapped joined V-belt that can improve the adhesive strength between the wrapped V-belt portion and the tie band and has excellent abrasion resistance and lateral pressure resistance, and a method for manufacturing the same.

[0017] Another object of the present invention is to provide a wrapped coupled V-belt that can suppress separation between the wrapped V-belt portion and the tie band and has excellent durability (endurance life), and a method for manufacturing the same.

[0018] As a result of intensive research into achieving the above object, the inventors of the present invention have found that if the outer peripheral surface of a wrapped V-belt portion is provided with a covered region covered with an outer covering fabric and an uncovered region that is not covered, and if the outer covering fabric that covers the side surfaces of the wrapped V-belt portion is used to cover the side portions of the outer peripheral surface to form the covered region (if the outer covering fabric is folded from the side surface toward the outer peripheral surface), not only can the adhesive strength with the tie band be effectively improved, but peeling of the outer covering fabric at the boundary with the tie band can also be suppressed, and have completed the present invention. That is, the present invention may include the following aspects, etc.

[0019] Aspect [1]: A wrapped connected V-belt including a plurality of wrapped V-belt portions whose belt main body portions are covered with an outer covering fabric, and tie bands that connect the plurality of wrapped V-belt portions on the outer peripheral surfaces of each wrapped V-belt portion, wherein the outer peripheral surface of the wrapped V-belt portion has a covered region that is covered with the outer covering fabric and an uncovered region that is not covered, and the covered region is formed on at least one side of the outer peripheral surface, and the outer covering fabric that covers this covered region also covers the side surface of the wrapped V-belt portion.

[0020] Aspect [2]: The wrapped, joined V-belt according to aspect [1], wherein the covered and uncovered regions are formed to extend in the belt length direction.

[0021] Aspect [3]: The wrapped connected V-belt according to aspect [1] or [2], wherein the covering region is formed on both sides of the outer circumferential surface.

[0022] Aspect [4]: ​​The wrapped joined V-belt according to any one of aspects [1] to [3], wherein the area ratio of the uncovered region is 25 to 95% (e.g., 25 to 85%) of the area of ​​the outer peripheral surface of the wrapped V-belt portion.

[0023] Aspect [5]: The wrapped coupled V-belt according to any one of aspects [1] to [4], wherein the belt body is covered with one to three layers of outer covering fabric.

[0024] Aspect [6]: The wrapped joined V-belt according to any one of Aspects [1] to [5], wherein the belt body is covered with a plurality of layers of outer covering fabric.

[0025] Aspect [7]: The wrapped coupled V-belt according to any one of Aspects [1] to [6], wherein the belt body is covered with a plurality of outer cover fabric layers, a first outer cover fabric layer located outermost among the plurality of outer cover fabric layers forms the covered region on the outer circumferential surface (covers a part of the outer circumferential surface), and one or more second outer cover fabric layers located inside the first outer cover fabric layer do not cover the outer circumferential surface (do not form the covered region).

[0026] Aspect [8]: The wrapped, joined V-belt according to any one of aspects [1] to [7], wherein the tie band includes at least a fiber.

[0027] Aspect [9]: A method for manufacturing a wrapped coupled V-belt, comprising at least a covering step of covering a belt body precursor with an outer covering fabric precursor to form a wrapped V-belt precursor, and a connecting step of connecting outer peripheral surfaces of a plurality of the wrapped V-belt precursors obtained in the covering step with tie band precursors, wherein in the covering step, the inner peripheral surface and both side surfaces of the belt body precursor are covered, and at least one side of the outer peripheral surface is covered with the outer covering fabric precursor that covers the side surfaces, and a partial region of the outer peripheral surface is not covered. The method for manufacturing a wrapped coupled V-belt according to any of Aspects [1] to [8].

[0028] Aspect

[10] : The manufacturing method according to aspect [9], which does not include a removing step of cutting or removing the outer covering fabric precursor covering the outer peripheral surface side of the wrapped V-belt portion precursor obtained in the covering step.

[0029] Aspect

[11] : The manufacturing method according to aspect [9] or

[10] , wherein in the covering step, the width of the outer cover fabric precursor is shorter than the perimeter of a cross-sectional shape perpendicular to the longitudinal direction of the belt body precursor, and the width direction of the outer cover fabric precursor is oriented in a direction perpendicular to the belt length direction.

[0030] Aspect

[12] : The manufacturing method according to any one of Aspects [9] to

[11] , wherein in the covering step, the inner peripheral surface, both side surfaces, and at least one side of the outer peripheral surface of the belt body precursor are covered with a seamless (single continuous sheet) outer cover fabric precursor.

[0031] In the present invention, the outer peripheral surface of the wrapped V-belt portion is formed with a covered region covered by the outer covering fabric and an uncovered region, and the outer covering fabric covering the side surface of the wrapped V-belt portion covers at least one side of the outer peripheral surface to form a covered region (covering by folding from the side surface toward the outer peripheral surface). This effectively improves the adhesive strength between the wrapped V-belt portion and the tie bands and effectively suppresses peeling of the outer covering fabric at the boundary between the side surface of the wrapped V-belt portion and the tie bands. Furthermore, it is possible to achieve both improved adhesive strength and improved productivity (or reduced reject rate). In addition, it is also possible to achieve improved wear resistance and improved resistance to side pressure. Furthermore, it is possible to provide a wrapped joined V-belt that suppresses peeling between the wrapped V-belt portion and the tie bands and has excellent durability (endurance life).

[0032] FIG. 1 is a schematic, partially cross-sectional perspective view showing an example of a conventional wrapped-connected V-belt. FIG. 2 is a schematic, partially cross-sectional view showing another example of a conventional wrapped-connected V-belt. FIG. 3 is a schematic, partially cross-sectional view showing yet another example of a conventional wrapped-connected V-belt. FIG. 4 is a schematic, partially cross-sectional view showing an example of a wrapped-connected V-belt of the present invention. FIG. 5 is a schematic, partially cross-sectional view showing another example of a wrapped-connected V-belt of the present invention. FIG. 6 is a schematic, partially cross-sectional view showing yet another example of a wrapped-connected V-belt of the present invention. FIG. 7 is a schematic, partially cross-sectional view showing another example of a wrapped-connected V-belt of the present invention. FIG. 8 is a graph showing the relationship between the proportion of uncovered area and the peel force of the tie band for the wrapped-connected V-belts obtained in the Examples, Reference Examples, and Comparative Examples. FIG. 9 is a schematic diagram showing the layout of a biaxial running test machine used to evaluate the wear resistance (wear rate) of the wrapped-connected V-belts obtained in the Examples and Reference Examples. FIG. 10 is a schematic diagram showing the layout of a triaxial running test machine used to evaluate the durability life of the wrapped-connected V-belts obtained in the Examples and Reference Examples.

[0033] 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).

[0034] The wrapped coupled V-belt of the present invention includes a plurality of wrapped V-belt sections, each having a belt body covered with an outer covering fabric, and tie bands connecting the wrapped V-belt sections at their outer peripheral surfaces, and the outer peripheral surfaces of the wrapped V-belt sections have covered regions covered with the outer covering fabric and uncovered regions. A schematic partial cross-sectional view of an example of the wrapped coupled V-belt of the present invention is shown in Figure 4.

[0035] The wrapped coupled V-belt 1 shown in FIG. 4 differs from the conventional wrapped coupled V-belts shown in FIGS. 1 to 3 in that the outer peripheral surface of the wrapped V-belt portion V (or belt body portion) has a covered region 5a covered with an outer covering fabric 5 and an uncovered region 4a (a portion where the tension rubber layer 4 is exposed) that is not covered.

[0036] That is, the wrapped coupled V-belt 1 is composed of a belt main body portion in which a plurality of wrapped V-belt portions V (two in the figure) are arranged in parallel at intervals in the belt width direction, and in which a compressed rubber layer 2, a core (core layer or core wire) 3, and a tension rubber layer 4 are laminated in this order from the inner peripheral side of the belt to the outer peripheral side (back side), and an outer cover cloth 5 that covers the periphery of this belt main body portion, and this outer cover cloth 5 covers the inner peripheral surface of the belt, both side surfaces, and a part of the outer peripheral surface, so that the covered region 5a and the uncovered region (exposed portion of the tension rubber layer 4) 4a are formed on the outer peripheral surface side of the wrapped V-belt portion V.

[0037] The covered region 5a and the uncovered region (exposed portion of the tension rubber layer 4) 4a are formed to extend in the belt length direction, and preferably are formed over the entire length or circumference of the belt in the belt length direction or circumferential direction, like the other elements (compression rubber layer 2, core 3, tension rubber layer 4, outer cover fabric 5, and tie band (connecting member) T).

[0038] In this wrapped bonded V-belt 1, the exposed portion (exposed surface) of the tension rubber layer 4 exposed in the uncovered region 4a can come into direct contact with the tie band T, and therefore can be bonded or connected to the tie band T with high adhesive strength due to crosslinking when forming the tension rubber layer 4.

[0039] The uncovered region 4a (exposed portion of the tension rubber layer 4) is formed in the center or interior of the belt outer circumferential surface (an inner region on the outer circumferential surface spaced from both ends in the belt width direction), while the covered region 5a is formed on both sides of the belt outer circumferential surface (regions on the outer circumferential surface near both ends in the belt width direction). In this example, the outer cover fabric 5 is formed of a seamless (continuous) fabric, so the inner circumferential surface, both side surfaces, and partial regions of the outer circumferential surface of the belt (covered regions 5a on both sides of the outer circumferential surface) are covered seamlessly (continuously). Therefore, the ends of the outer cover fabric 5 covering the inner circumferential surface and both side surfaces of the belt are folded (or buried) between the belt main body and the tie band T as the covered region 5a. In this manner, in a configuration in which the end of the outer cover cloth 5 is folded (or buried) (i.e., in a configuration in which the outer cover cloth 5 covering the covering region 5a also covers the side surface of the wrapped V-belt portion V), the end of the outer cover cloth 5 does not come into contact with pulleys or the like. Therefore, unlike the conventional wrapped joined V-belt 121 shown in FIG. 3, peeling of the outer cover cloth 5 at the boundary between the side surface of the wrapped V-belt portion V and the tie band T can be effectively suppressed.

[0040] Furthermore, as in this example, when the outer cover fabric is formed of a continuous (seamless) fabric in the circumferential direction of the belt cross section (cross section perpendicular to the belt length direction), the belt can be continuously covered along the belt length direction with a single continuous outer cover fabric precursor (fabric) in the covering step described later in the manufacturing method section, which effectively improves productivity.

[0041] In this example, the outer cover fabric 5 is a continuous piece of fabric that is seamless in the circumferential direction of the belt cross section (a cross section perpendicular to the belt length direction). However, a fabric formed by joining (connecting) the ends of two or more pieces of fabric or by partially overlapping and joining them may also be used. For example, the outer cover fabric 5 in FIG. 4 may be formed by two pieces of fabric that are overlapped on the inner circumferential surface of the belt or one side surface (e.g., overlapped on the inner circumferential surface of the belt, as in the outer cover fabric 125 of the conventional wrapped-connected V-belt 121 shown in FIG. 3). That is, one piece of fabric may continuously cover the inner circumferential surface of the belt, one side surface, and one covering region, and the other piece of fabric joined to this fabric on the inner circumferential surface of the belt may cover the inner circumferential surface of the belt, the other side surface, and the other covering region. In this embodiment, the inner circumferential surface of the belt can be effectively reinforced without forming a belt main body portion provided with a reinforcing fabric layer or the like on the inner circumferential surface of the compressed rubber layer.

[0042] Figure 5 shows a schematic partial cross-sectional view of another example of a wrapped bonded V-belt of the present invention. The wrapped bonded V-belt 11 shown in Figure 5 differs from the wrapped bonded V-belt 1 shown in Figure 4 in that a covered region 15a is formed on one side of the outer circumferential surface and no covered region is formed on the other side (the remaining portion of the outer circumferential surface other than the covered region 15a formed on only one side is an uncovered region 14a). Therefore, the compressed rubber layer 12 and core 13 are the same as the compressed rubber layer 2 and core 3 of the wrapped bonded V-belt 1, and the tensile rubber layer 14 and outer cover fabric 15 are the same as the tensile rubber layer 4 and outer cover fabric 5, except that their shapes correspond to the uncovered region 14a and covered region 15a. In this embodiment, the area of ​​the uncovered region 14a is large, thereby more effectively improving adhesive strength.

[0043] Furthermore, when a covering region is formed on one side, it is preferable to form at least the covering region on the outermost side in the belt width direction of the wrapped connected V-belt (i.e., on the outer peripheral side in the belt width direction of the outermost (both ends) wrapped V-belt portion in the belt width direction). For example, in the case of a wrapped connected V-belt having two wrapped V-belt portions, it is preferable to form at least the covering region on both ends in the belt width direction in the positional relationship shown in FIG. 5. This configuration can effectively prevent peeling of the outer covering fabric. That is, when used in a layout in which an idler pulley or a tension pulley (tensioner) is provided on the back side (tie band side) of the wrapped connected V-belt, both ends in the belt width direction tend to frequently come into contact with the flange portions of these pulleys [restricting portions or restricting walls formed on both sides in the thickness direction (axial direction) of the pulley to prevent belt deviation]. Therefore, the outer covering fabric tends to peel more easily at the outermost side in the belt width direction, but forming the covering region on the outermost side (both ends) in the belt width direction can effectively prevent peeling of the outer covering fabric.

[0044] Figure 6 shows a schematic partial cross-sectional view of yet another example of a wrapped connected V-belt of the present invention. The wrapped connected V-belt 21 shown in Figure 6 differs from the wrapped connected V-belt 1 shown in Figure 4 in that it has two outer cover layers, but other components (compressed rubber layer 22, core 23, etc.) are similar to the wrapped connected V-belt 1. In the wrapped connected V-belt 21 of Figure 6, the periphery of the belt body is covered with a first outer cover fabric (outer outer cover fabric) 25 located on the outside and a second outer cover fabric (inner outer cover fabric) 26 located inside (on the belt body side) of the first outer cover fabric. The inner second outer cover cloth 26 is formed of a continuous (continuous) fabric, similar to the outer cover cloth 5 in the wrapped-connected V-belt 1 in Fig. 4, and covers the inner circumferential surface, both side surfaces, and a portion of the outer circumferential surface (covered areas on both sides of the outer circumferential surface) 26a of the belt without any interruption (continuous form), and the first outer cover cloth 25 formed of a continuous (continuous) fabric similarly covers the outer side of the belt (outside the second outer cover cloth 26) along this second outer cover cloth 26, forming covered areas 25a on both sides of the belt outer circumferential surface. In this embodiment in which the outer cover cloth is formed in multiple layers, exposure of the rubber of the belt main body can be effectively prevented even if wear of the outer cover cloth progresses on the side surfaces of the V-belt portion.

[0045] 4, in this example, the uncovered region 24a [exposed portion (exposed surface) of the tension rubber layer 24] can come into direct contact with the tie band T, and therefore can be bonded or connected to the tie band T with high adhesive strength due to crosslinking. Furthermore, the outer cover fabrics 25, 26 that cover the covered regions 25a, 26a also cover the belt side surfaces (i.e., the ends of the outer cover fabrics 25, 26 are folded or buried at the boundary with the tie band T), which effectively prevents peeling from the ends of the outer cover fabrics 25, 26 at the boundary. Furthermore, productivity can be effectively improved in the covering process, which will be described later in the manufacturing method section.

[0046] In this example, both outer cover cloths 25, 26 cover the same region of the outer surface of the belt body, but when the outer cover cloth is formed in multiple layers, the multiple outer cover cloths may cover the same or different regions to form covered regions. For example, each covered region 25a of the first outer cover cloth (outer outer cover cloth) 25 may extend further toward the center of the outer surface than each covered region 26a of the second outer cover cloth (inner outer cover cloth) 26 (i.e., the order from one side of the outer surface to the other is covered region 25a (laminated with 26a), covered region 25a (single layer), uncovered region 24a, covered region 25a (single layer), and covered region 25a (laminated with 26a)); On one side, the covered region 25a extends further toward the center of the outer circumferential surface than the covered region 26a, and on the other side, the covered region 26a extends further toward the center of the outer circumferential surface than the covered region 25a (the order from one side of the outer circumferential surface to the other is covered region 25a (laminated with 26a), covered region 25a (single layer), uncovered region 24a, covered region 26a (single layer), and covered region 25a (laminated with 26a)). Also, it is not necessary for all of the outer covering fabric layers to form a covered region.

[0047] For example, Fig. 7 shows a schematic partial cross-sectional view of another example of a wrapped connected V-belt of the present invention. The wrapped connected V-belt 31 shown in Fig. 7 differs from the wrapped connected V-belt 21 shown in Fig. 6 in that the second outer cover fabric (inner outer cover fabric) 36 located on the inside does not cover the outer circumferential surface of the belt (does not form a covered region), but other configurations (compressed rubber layer 32, core body 33, etc.) are similar to those of the wrapped connected V-belt 21 (or 1). That is, in the wrapped V-belt 31 shown in Fig. 7, the second outer cover fabric (inner outer cover fabric) 36 located on the inside does not form a covering region on the outer peripheral surface, and only covers the inner peripheral surface and both side surfaces of the belt with a continuous (continuous) fabric, whereas the first outer cover fabric (outer outer cover fabric) 35 located on the outside covers the inner peripheral surface and both side surfaces of the belt with a continuous (continuous) fabric, and also covers both sides of the outer peripheral surface to form a covering region 35a (both ends of the fabric are folded or buried at the boundary with the tie band T). In this configuration, as with the wrapped V-belt 21 shown in Fig. 6, even if the outer cover fabric wears on the side surfaces of the V-belt portion, the multiple layers of outer cover fabric effectively prevent the rubber of the belt main body from being exposed. Furthermore, since the covering region is formed of a single layer of outer cover fabric, a decrease in the flexibility of the belt is effectively suppressed. Furthermore, the cost of the material for the outer cover fabric can be reduced, which is advantageous from a cost perspective.

[0048] Furthermore, when a belt has good flexibility (can be bent with little force), the stress generated by bending is small, making it less likely to crack and improving durability. In addition, less energy is consumed (heat is generated and dissipated) during bending, which tends to improve transmission efficiency.

[0049] In this example, as with the wrapped bonded V-belt 21 (or 1) of FIG. 6 (or FIG. 4), the uncovered region 34a (exposed portion (exposed surface) of the tension rubber layer 34) can come into direct contact with the tie band T, thereby bonding or connecting the tie band T with high adhesive strength through cross-linking. Furthermore, since the first outer cover fabric (outer outer cover fabric) 35 covering the covered region 35a also covers the belt side surface (i.e., the outer edge of the first outer cover fabric 35 is folded or buried at the boundary with the tie band T), peeling from the edge of the outer cover fabric at the boundary can be effectively suppressed even if the edge of the second outer cover fabric (inner outer cover fabric) 36 is not folded in. Furthermore, productivity can be effectively improved in the covering process, which will be described later in the manufacturing method section.

[0050] 7 is configured with two layers: an outermost first outer layer (outer outer layer) 35 and an inner second outer layer (inner outer layer) 36. However, two layers are not necessarily required, and multiple inner second outer layer layers may be stacked. When the inner second outer layer is configured with multiple layers, at least one of the second outer layer layers may form a covering region that covers the outer circumferential surface of the belt. However, from the viewpoint of improving the flexibility of the belt and reducing material costs, it is preferable that not all of the multiple second outer layer layers (inner outer layer layers) form a covering region, and that only the outermost first outer layer (outer outer layer) form a covering region. Therefore, it is preferable that one or more second outer layer layers (inner outer layer layers) cover at least a selected region of the inner circumferential surface and both side surfaces of the belt (preferably the inner circumferential surface and both side surfaces of the belt) without covering the outer circumferential surface of the belt.

[0051] [Outer Cover Fabric] The outer cover fabric (cover fabric) is formed from a conventional fabric. Examples of fabrics include woven fabrics, knitted fabrics (weft-knitted fabrics and warp-knitted fabrics), and nonwoven fabrics. Among these, woven fabrics woven in a plain weave, twill weave, satin weave, or other form, and woven or knitted fabrics woven at a wide angle between the warp and weft threads exceeding 90° and not exceeding 120° are preferred. Woven fabrics commonly used as cover fabrics for transmission belts in general industrial and agricultural machinery are particularly preferred [plain weave fabrics in which the warp and weft threads cross at a right angle, and plain weave fabrics (wide-angle canvas) in which the warp and weft threads cross at a wide angle between the warp and weft threads exceeding 90° and not exceeding 120°]. Furthermore, wide-angle canvas may be used for applications requiring durability.

[0052] From the viewpoint of flexibility, the outer cover fabric is preferably arranged so that the extending direction of the warp and weft threads intersects with the longitudinal direction of the belt. The directions of the warp and weft threads may be arranged so that they each form an angle of, for example, 45 to 75° (e.g., 50 to 70°), preferably about 55 to 65°, with respect to the longitudinal direction of the belt.

[0053] Commonly used fibers for the fabric include synthetic fibers such as polyolefin fibers (polyethylene fibers, polypropylene fibers, etc.), polyamide fibers (polyamide 6 fibers, polyamide 66 fibers, polyamide 46 fibers, aramid fibers, etc.), polyester fibers (polyalkylene arylate fibers, etc.), vinyl alcohol fibers (polyvinyl alcohol fibers, ethylene-vinyl alcohol copolymer fibers, vinylon fibers, etc.), and polyparaphenylene benzobisoxazole (PBO) fibers; cellulose fibers (cellulose fibers, cotton, cellulose derivative fibers, etc.), natural fibers such as hemp and wool; and inorganic fibers such as carbon fibers. These fibers may be used alone as a single yarn, or may be a blended yarn in which two or more types are combined.

[0054] Among these fibers, blended yarns of polyester fibers and cellulosic fibers are preferred because of their excellent mechanical properties and economical cost.

[0055] 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 Examples include arylate fibers.

[0056] 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.), ginseng bark fibers (hemp, paper mulberry, Mitsumata, etc.), and leaf fibers (Manila hemp, New Zealand hemp, etc.); cellulose fibers derived from animals 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.).

[0057] The mass ratio of polyester fiber to cellulosic fiber is, for example, about 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).

[0058] The average fineness of the fibers constituting the fabric is, for example, about 5 to 30 count, preferably about 10 to 25 count, and more preferably about 15 to 25 count.

[0059] The basis weight of the fabric (raw fabric) is, for example, 100 to 500 g / m ２ , preferably 200 to 400 g / m ２ , more preferably 250 to 300 g / m ２ That's about it.

[0060] When the fabric (raw fabric) is a woven fabric, the thread density (warp thread density, weft thread density) of the fabric is, for example, about 60 to 100 threads / 50 mm, preferably about 65 to 90 threads / 50 mm, and more preferably about 70 to 80 threads / 50 mm.

[0061] The outer covering fabric 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 the belt body. Examples of adhesive components (or surface treatment agents) used in the adhesive treatment include isocyanates (polyisocyanate compounds), epoxy resins (epoxy compounds), silane coupling agents, amino resins, rubber components (e.g., rubber latex or rubber cement), and RFL liquids containing resorcinol (R), formaldehyde (F), and rubber or latex (L) [e.g., RFL liquids containing a condensate (RF condensate) of resorcinol (R) and formaldehyde (F) and a rubber component such as vinylpyridine-styrene-butadiene copolymer rubber]. These may be used alone or in combination, and may be treated multiple times sequentially with the same or different adhesive components.

[0062] Among these adhesive components, a rubber component, an RFL liquid, or a combination thereof is preferred. The rubber component is preferably an adhesive component containing the same type (preferably the same) of rubber component as the rubber component of the belt main body (e.g., tension rubber layer, compression rubber layer).

[0063] The adhesive treatment using a rubber component may be, for example, a treatment of soaking (immersing) the fabric in a rubber paste prepared by dissolving a rubber composition containing the rubber component in a solvent, a treatment of rubbing (rubbing) the solid rubber composition into the fabric, etc. The adhesive treatment may be performed on at least one surface of the fabric, and it is preferable to treat at least the surface (particularly both surfaces) that comes into contact with the belt main body.

[0064] Examples of the rubber component constituting the rubber composition to be adhered to the outer covering fabric (rubber composition for adhesive treatment) include the same rubber components, including preferred embodiments, as those exemplified in the section on the tension rubber layer described below. The rubber component in the rubber composition for adhesive treatment is preferably the same type (particularly the same) of rubber component as the rubber component in the crosslinked rubber composition forming the tension rubber layer and / or compression rubber layer.

[0065] In addition to the rubber component, the rubber composition for adhesion treatment may or may not contain conventional additives as needed, such as the same additives as those exemplified in the section on the tension rubber layer described below, including preferred embodiments thereof.

[0066] The basis weight of the fabric after the adhesive treatment (treated fabric) is, for example, 300 to 800 g / m ２ , preferably 400 to 600 g / m ２ , more preferably 450 to 550 g / m ２ That's about it.

[0067] The average thickness of the outer covering fabric (the average thickness of each layer in the case of a multi-layer structure) is, for example, about 0.4 to 2 mm, preferably about 0.45 to 1.4 mm, and more preferably about 0.5 to 1 mm (for example, 0.55 to 0.8 mm). If the thickness of the outer covering fabric is too thin, the abrasion resistance may decrease, and if it is too thick, the flexibility of the belt may decrease.

[0068] The coefficient of friction of the outer covering fabric, which is the power transmission surface, is, for example, 0.9 to 1, preferably 0.91 to 0.96, and more preferably about 0.92 to 0.95. In this specification and claims, the coefficient of friction can be measured by the method described in JP 2022-85864 A.

[0069] The outer cover fabric may be a single layer formed from a single outer cover fabric, as long as it can form a covered region and an uncovered region on the outer peripheral surface of the belt. From the viewpoint of easier improvement in abrasion resistance, the outer cover fabric may be a multi-layer or multi-layer structure in which multiple outer cover fabrics are laminated (for example, 2 to 5 layers, preferably 2 to 4 layers, more preferably 2 to 3 layers, and particularly 2 layers). From the viewpoints of productivity and lateral pressure resistance, for example, 1 to 3 layers [for example, a single layer (1 ply) or 2 layers (2 plies)] are preferred. From the viewpoints of a good balance between productivity, abrasion resistance, and lateral pressure resistance and excellent durability, 2 to 3 layers are more preferred, and 2 layers are particularly preferred. If the number of layers of the outer covering fabric is too large, productivity may decrease and side pressure resistance may also decrease (and therefore durability may also decrease). On the other hand, if the number of layers is too small, when manufacturing in accordance with the manufacturing method described below, portions of the belt side (transmission surface) may easily be left uncovered by the outer covering fabric during the covering process (rubber may easily be exposed from the side), which may not only decrease productivity and abrasion resistance but also cause rubber to easily seep out or be exposed from the outer covering fabric that wears during belt operation, which may increase the coefficient of friction with the pulley and generate heat (heat generation may reduce the adhesive strength between the wrapped V-belt portion and the tie band), thereby decreasing durability.

[0070] When the outer cover cloth is made up of multiple layers (multiple layers of outer cover cloth stacked together), each of the multiple outer cover cloths may cover the same or different regions of the outer surface of the belt body, forming a covering region. Furthermore, not all of the multiple outer cover cloth layers need to form a covering region; at least one outer cover cloth layer may form a covering region. For example, a first outer cover cloth located on the outermost side (closer to the pulley) may cover at least the outer surface of the belt (forming a covering region), and one or more second outer cover cloths (inner outer cover cloths) located inside (closer to the belt body) of the first outer cover cloth (outer outer cover cloth) may cover the outer surface. However, from the viewpoints of belt flexibility and reducing material costs, it is preferable that they do not cover the outer surface (do not form a covering region).

[0071] The outer cover fabric covering at least the inner circumferential surface and both side surfaces of the belt is usually formed to extend in the belt length direction. On the outer circumferential surface of the belt, at least the covered region covered by the outer cover fabric and the uncovered region not necessarily need to extend in the belt length direction, but from the viewpoint of productivity, they are preferably formed to extend in the belt length direction. The fabric forming the outer cover fabric (or the fabric forming each layer in the case of a multi-layered outer cover fabric) is preferably a continuous fabric without any gaps (a single continuous piece) in the circumferential direction and / or the belt length direction of the belt cross section (a cross section perpendicular to the belt length direction). That is, the fabric forming the outer cover fabric is preferably a single continuous piece of fabric capable of covering at least the inner circumferential surface and both side surfaces of the belt [preferably, at least one side portion (particularly both sides) of the outer circumferential surface] over the entire length of the belt.

[0072] In this application, an unbroken or continuous fabric (outer covering fabric or outer covering fabric precursor) means that, prior to the covering step (or in the state of the outer covering fabric precursor), the fabric may have joints (connections) or the like, as long as it is a single piece of fabric that can be wound up independently. For example, this also includes fabrics in which the ends of two or more pieces of fabric are joined (connected) or partially overlapped and joined.

[0073] The covering region is preferably formed on at least one side of the outer peripheral surface of the belt in a vertical cross section in the longitudinal direction of the belt (preferably on both sides, as this makes it easier to achieve both adhesion to the tie band and productivity), and it is preferable that the outer covering fabric covering this covering region (the side of the outer peripheral surface of the belt) also covers the side surfaces of the belt, i.e., if the ends of the outer covering fabric covering the side surfaces of the belt are folded or buried at the boundary with the tie band, this effectively prevents the ends of the outer covering fabric from peeling off from the boundary.

[0074] The area ratio of the uncovered region relative to the area (total area of ​​the covered and uncovered regions) of the outer peripheral surface of the wrapped V-belt portion (crosslinked wrapped V-belt portion) may be, for example, about 1 to 99% (e.g., 15 to 97%, preferably 25 to 95%), or about 10 to 90% (e.g., 20 to 90%), more preferably about 25 to 85% (e.g., 26 to 83%), and even more preferably about 30 to 80% (e.g., 40 to 70%). However, from the viewpoint of an excellent balance of adhesion to the tie band, abrasion resistance (particularly, ease of suppressing peeling of the outer covering fabric at the boundary with the tie band), and productivity (particularly, workability and high yield in the covering process), it is particularly preferably 50 to 90% (e.g., 55 to 85%, preferably 60 to 80%, more preferably 65 to 75%). The above area ratio may be the area ratio in an embodiment in which the outer covering fabric is a single layer (one layer) or multiple layers (particularly, a single layer). Furthermore, when the outer fabric is made of multiple layers (e.g., 2 to 4 layers, preferably 2 to 3 layers, and particularly 2 layers), the area ratio of the uncovered region to the area of ​​the outer peripheral surface of the wrapped V-belt portion may be, for example, about 20 to 98% (e.g., 25 to 95%), preferably about 30 to 97% (e.g., 40 to 95%), more preferably 45 to 96% (e.g., 50 to 95%, preferably 55 to 85%, especially 60 to 80%), even more preferably about 60 to 95% (e.g., 65 to 93%, preferably 65 to 75%), especially preferably about 68 to 92% (e.g., 70 to 90%). From the viewpoint of an excellent balance between adhesion to the tie band, abrasion resistance (especially ease of preventing peeling of the outer fabric at the boundary with the tie band), and productivity (especially workability and high yield in the covering step), it is particularly preferably about 50 to 90% (e.g., 55 to 85%, preferably 60 to 80%, and even more preferably 65 to 75%). If the proportion of the uncovered area is too small, there is a risk that the adhesive strength (or peeling strength) with the tie band may not be sufficiently secured. On the other hand, if the proportion of the uncovered area is too large, for example, when manufacturing based on the manufacturing method described below, it may become difficult to align the outer cover cloth with the belt main body during the covering process, and there is a risk that areas on the side surface of the belt (transmission surface) that are not covered by the outer cover cloth may easily occur (reducing productivity).In a wrapped V-belt, if the rubber is exposed on the belt side (power transmission surface), the friction coefficient on the belt side may be locally high, resulting in non-uniform characteristics or properties in the circumferential direction, and a significant decrease in wear resistance and noise resistance, which may make the belt unusable for its intended use. However, when the outer covering fabric is made of multiple layers, even if the proportion of uncovered regions is relatively high, it tends to be easier to effectively prevent areas from being uncovered by the outer covering fabric (which would result in reduced productivity).

[0075] In the present application, the area ratio of the uncoated region can be measured according to the method described in the examples below.

[0076] [Belt Main Body] The belt main body is covered on its inner circumferential surface, both side surfaces, and a portion of its outer circumferential surface with an outer covering fabric to form a wrapped V-belt. For example, the wrapped V-belt may be a V-belt (V-belt portion) including an endless belt main body (belt main body) with a V-shaped cross section, including an inner compressed rubber layer, an outer tensile rubber layer, and a core layer (adhesive rubber layer) with embedded cords interposed therebetween, and the outer covering fabric (cover fabric) covering the periphery of the V-shaped cross section of the belt main body along the entire length of the belt (belt circumferential direction), with both left and right side surfaces of the V-shaped cross section covered by the outer covering fabric serving as frictional power transmission surfaces. In the V-shaped cross section, the wider side is the outer circumferential side, and the narrower side is the inner circumferential side. If necessary, a reinforcing fabric layer may be included on the inner circumferential surface of the compressed rubber layer along the belt length.

[0077] On the outer peripheral surface side (surface of the tension rubber layer) of the wrapped V-belt portion (belt main body portion), an uncovered region that is not covered with the outer covering fabric is formed, exposing the tension rubber layer, and this exposed tension rubber layer can be firmly adhered or bonded to the tie band during crosslinking (the connecting step in the manufacturing method described below), ensuring sufficient adhesive strength (peel strength).

[0078] (Tension Rubber Layer) The tension rubber layer may be formed of a vulcanized or crosslinked rubber composition that is commonly used as a rubber composition (rubber composition containing a rubber component) for wrapped V-belts.

[0079] The rubber component in the cross-linked rubber composition forming the tension rubber layer can be selected from known vulcanizable or cross-linkable rubbers and / or elastomers, such as diene rubbers (natural rubber, isoprene rubber, butadiene rubber, chloroprene rubber (CR), styrene-butadiene rubber (SBR), vinylpyridine-styrene-butadiene copolymer rubber, acrylonitrile-butadiene rubber (nitrile rubber), hydrogenated 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, fluororubber, etc. These rubber components can be used alone or in combination.

[0080] Among these, ethylene-α-olefin elastomers (ethylene-α-olefin rubbers) such as ethylene-propylene copolymer (EPM) and ethylene-propylene-diene terpolymer (EPDM) and chloroprene rubber are widely used because of the ease of diffusion of the crosslinking agent (or vulcanizing agent) and crosslinking accelerator (or vulcanization accelerator). In particular, when used in high-load environments such as variable speed belts, chloroprene rubber and EPDM are preferred because of their excellent balance of mechanical strength, weather resistance, heat resistance, cold resistance, oil resistance, and adhesiveness. Chloroprene rubber may be either sulfur-modified or non-sulfur-modified. Furthermore, ethylene-α-olefin elastomers such as EPDM are particularly preferred because they have superior heat resistance and weather resistance compared to chloroprene rubber, and can be highly loaded with reinforcing agents, making it easy to increase mechanical strength. Ethylene-α-olefin elastomers such as EPDM tend to have lower adhesiveness than chloroprene and are prone to peeling from the tie band. However, in the wrapped bonded V-belt of the present invention, even if an ethylene-α-olefin elastomer such as EPDM is used as the rubber component of the tension rubber layer, the belt can be bonded to the tie band with high adhesive strength, and peeling of the tie band can be effectively prevented.

[0081] When the rubber component contains an ethylene-α-olefin elastomer such as EPDM, the proportion of the ethylene-α-olefin elastomer (particularly, EPDM) in the rubber component may be, for example, 50% by mass or more (particularly, about 80 to 100% by mass), and 100% by mass (only ethylene-α-olefin elastomer such as EPDM) is particularly preferred.

[0082] In the ethylene-α-olefin elastomer, the ethylene content (proportion of ethylene units) in the ethylene-α-olefin elastomer may be 30% by mass or more, for example, 35 to 70% by mass, preferably 40 to 60% by mass, and more preferably 45 to 55% by mass. If the ethylene content is too high, there is a risk that processability and crack resistance will decrease.

[0083] In the present application, the ethylene content means the mass proportion of ethylene units in all units constituting the ethylene-α-olefin elastomer, and can be measured by a conventional method, but may also be the proportion based on ethylene as a monomer.

[0084] Furthermore, in the present application, when there are multiple types of ethylene-α-olefin elastomers, the ethylene content means an average value based on the mass ratio (average ethylene content), i.e., the average ethylene content is the sum of the products of the ethylene contents and the mass fractions of the respective ethylene-α-olefin elastomers.

[0085] In the ethylene-α-olefin elastomer, the ratio (mass ratio) of ethylene to α-olefin (former / latter) may be about 40 / 60 to 90 / 10, preferably 45 / 55 to 80 / 20, further preferably 50 / 50 to 70 / 30, and even more preferably 50 / 50 to 60 / 40.

[0086] The diene content (particularly, the ethylidene norbornene content) of the ethylene-α-olefin elastomer (particularly, an ethylene-α-olefin-diene terpolymer such as EPDM) may be, for example, about 0.1 to 15 mass%, preferably 1 to 10 mass%, further preferably 2 to 8 mass%, even more preferably 3 to 7 mass%, and most preferably 4 to 6 mass%. If the diene content is too high, there is a risk that high heat resistance cannot be ensured. If the diene content is too low, there is a risk that processability and crack resistance will decrease.

[0087] In the present application, the diene content means the mass proportion of diene monomer units in all units constituting the ethylene-α-olefin elastomer, and can be measured by a conventional method, but may also be a proportion based on the monomer.

[0088] The Mooney viscosity [ML(1+4)125°C] of the uncrosslinked ethylene-α-olefin elastomer may be, for example, about 10 to 85 (e.g., 12 to 50), preferably about 15 to 30, and more preferably about 18 to 25. If the Mooney viscosity is too high, there is a risk that the processability and crack resistance may decrease.

[0089] In this application, the Mooney viscosity [ML(1+4)125°C] can be measured by a method in accordance with JIS K 6300-1 (2013), and the test conditions are as follows: an L-shaped rotor is used, the test temperature is 125°C, preheating is 1 minute, and the rotor operating time is 4 minutes. The Mooney viscosity is used as an index of the fluidity (ease of processing) of rubber, measured by filling an uncrosslinked ethylene-α-olefin elastomer in a cavity so that it is in contact with a rotor having grooves on its surface, and measuring the torque required to rotate the rotor.

[0090] Furthermore, in the present application, when there are multiple types of ethylene-α-olefin elastomers, the Mooney viscosity refers to an average value (average Mooney viscosity) based on the mass ratio, i.e., the average Mooney viscosity is the sum of the products of the Mooney viscosities of the respective ethylene-α-olefin elastomers and the mass fractions thereof.

[0091] Additives The crosslinked (vulcanized) rubber composition may or may not contain conventional additives in addition to the rubber component, as necessary. Examples of additives include fillers, short fibers, crosslinking agents (or vulcanizing agents), co-crosslinking agents or crosslinking aids (or vulcanization aids), crosslinking accelerators (or vulcanization accelerators), crosslinking retarders (or vulcanization retarders), metal oxides (calcium oxide, barium oxide, iron oxide, copper oxide, titanium oxide, aluminum oxide, zinc oxide, etc.), softeners (oils such as paraffinic oils and naphthenic oils), processing agents or processing aids (for example, fatty acids such as stearic acid, fatty acid metal salts such as metal stearates, fatty acid amides such as stearamide, wax, paraffin, etc.), plasticizers [aliphatic carboxylic acid ester plasticizers (adipate ester plasticizers, sebacic acid ester plasticizers, etc.), aromatic carboxylic acid ester plasticizers (phthalate ester plasticizers, trimellitate ester plasticizers, etc.), oxycarboxylic acid ester plasticizers, phosphate ester plasticizers, etc.]. ester-based plasticizers, ether-based plasticizers, ether ester-based plasticizers, etc.], adhesion improvers [for example, resorcinol-formaldehyde co-condensates (RF condensates), amino resins (condensates of nitrogen-containing cyclic compounds and formaldehyde, for example, melamine resins such as hexamethylol melamine, hexaalkoxymethyl melamine (hexamethoxymethyl melamine, hexabutoxymethyl melamine, etc.), urea resins such as methylol urea, benzoguanamine resins such as methylol benzoguanamine resins, etc.), co-condensates thereof (resorcinol-melamine-formaldehyde co-condensates, etc.)], tackifiers, coupling agents (silane coupling agents, etc.), antiaging agents (antioxidants, heat antiaging agents, flex crack inhibitors, antiozonants, etc.), stabilizers (ultraviolet absorbers, heat stabilizers, etc.), flame retardants, colorants, lubricants, antistatic agents, etc. The metal oxide may act as a crosslinking agent depending on the type of rubber component, etc. In the adhesion improver, the resorcinol-formaldehyde co-condensate and the amino resin may be an initial condensate (prepolymer) of formaldehyde with a nitrogen-containing cyclic compound such as resorcinol and / or melamine.

[0092] Examples of the filler include carbon black, silica, clay, calcium carbonate, talc, and mica. The filler often contains a reinforcing filler, which may be carbon black, silica (reinforcing silica), or the like. The reinforcing ability of silica is generally less than that of carbon black. These fillers can be used alone or in combination. Among these fillers, reinforcing fillers such as carbon black and silica, and clay are preferred, and it is more preferred to contain at least a reinforcing filler. It is particularly preferred to contain a combination of carbon black and silica.

[0093] Carbon black is classified by ASTM as "N0**" to "N9**" (based on iodine adsorption), and has traditionally been classified into SAF, HAF, GPF, etc. based on the performance of rubber products. N110 (SAF), N220 (ISAF), N330 (HAF), etc., which have small primary particle sizes, are called hard carbon, while N550 (FEF), N660 (GPF), N762 (SRF), etc., which have large primary particle sizes, are sometimes called soft carbon. These carbon blacks can be used alone or in combination of two or more. Of these, SRF, ISAF, and HAF are preferred, and soft carbon such as SRF is more preferred.

[0094] The average primary particle size of the soft carbon may be, for example, 42 to 100 nm, preferably 45 to 80 nm, more preferably 50 to 75 nm, and more preferably 60 to 70 nm, while the average primary particle size of the hard carbon may be, for example, 10 to 38 nm, preferably 15 to 35 nm, more preferably 20 to 33 nm, and more preferably 25 to 30 nm.

[0095] The DBP absorption of carbon black can be selected, for example, from the range of about 50 to 500 mL / 100 g, and may preferably be about 60 to 120 mL / 100 g (for example, 60 to 80 mL / 100 g).

[0096] In this application, the DBP absorption amount of carbon black means a value (OAN) that can be measured on an uncompressed sample in accordance with JIS K 6217-4 (2017).

[0097] The iodine adsorption capacity of the carbon black may be, for example, about 5 to 200 g / kg, preferably about 10 to 140 g / kg (eg, 15 to 130 g / kg), and more preferably about 20 to 30 g / kg.

[0098] In the present application, the iodine adsorption amount of carbon black can be measured in accordance with the standard test method of ASTM D1510-17.

[0099] The BET specific surface area of ​​carbon black is, for example, 10 to 400 m ２ / g, preferably 15 to 150 m ２ / g (e.g., 20 to 120 m ２ / g), and more preferably 25 to 40 m ２ / g or so.

[0100] In the present application, the BET specific surface area means a specific surface area measured by the BET method using nitrogen gas.

[0101] Silica includes dry silica, wet silica, surface-treated silica, etc. Silica can also be classified by production method, such as dry-process white carbon, wet-process white carbon, colloidal silica, and precipitated silica. These silicas can be used alone or in combination. Among these silicas, silicas having surface silanol groups (silicic anhydride, silicic acid hydrate) are preferred, as silicic acid hydrates with many surface silanol groups have a strong chemical bond with rubber components.

[0102] The nitrogen adsorption specific surface area of ​​silica measured by the BET method is, for example, 50 to 400 m ２ / g, preferably 70 to 300 m ２ / g, more preferably 100 to 250 m ２ / g, more preferably 150 to 200m ２ / g.

[0103] The proportion of the filler (particularly the reinforcing filler) may be, for example, 10 to 100 parts by mass, preferably 20 to 80 parts by mass (e.g., 50 to 70 parts by mass) relative to 100 parts by mass of the rubber component. The proportion of the reinforcing filler may be, for example, 50% by mass or more, preferably 75% by mass or more (e.g., 80% by mass or more), more preferably 90% by mass or more, and may even be 100% by mass, relative to the total filler. The proportion of carbon black (particularly soft carbon) may be, for example, 0 to 100 parts by mass (e.g., 5 to 80 parts by mass), preferably about 5 to 15 parts by mass, relative to 100 parts by mass of the rubber component. The proportion of silica may be, for example, 0 to 100 parts by mass (e.g., 10 to 90 parts by mass), preferably about 25 to 75 parts by mass (e.g., 40 to 60 parts by mass), relative to 100 parts by mass of the rubber component. When both carbon black (particularly soft carbon) and silica are contained, the ratio of the two may be, for example, the former / latter (mass ratio) = 5 / 95 to 25 / 75, preferably about 10 / 90 to 20 / 80. If there is too much carbon black or too little silica, the adhesiveness may decrease, and the tie band or outer covering fabric may become easily peeled off.

[0104] Examples of the staple fibers include the fibers exemplified as fibers constituting the fabric in the section on the outer covering fabric. These staple fibers can be used alone or in combination of two or more. Among these staple fibers, polyester fibers (e.g., polyalkylene arylate fibers such as PET fibers), cellulosic fibers (e.g., cotton), or combinations thereof are preferred. When combining polyester fibers (e.g., polyalkylene arylate fibers such as PET fibers) with cellulosic fibers (e.g., cotton), the ratio of the two fibers (mass ratio) may be, for example, about 50 / 50 to 80 / 20 (former / latter), preferably about 60 / 40 to 70 / 30.

[0105] The average fiber diameter of the short fibers may be, for example, 2 μm or more, preferably about 2 to 100 μm, and the average length of the short fibers is, for example, about 1 to 20 mm, preferably about 1.5 to 10 mm, and more preferably about 2 to 8 mm (e.g., about 2.5 to 6.5 mm).

[0106] From the viewpoint of dispersibility and adhesiveness of the short fibers in the rubber composition, the short fibers may be subjected to a conventional adhesive treatment (or surface treatment) [e.g., treatment with a treatment liquid containing an adhesive component]. Examples of the adhesive component (or surface treatment agent) used in the adhesive treatment include the same components as those exemplified in the section on the outer covering fabric. These may be used alone or in combination of two or more, and the short fibers may be treated multiple times sequentially with the same or different adhesive components.

[0107] The short fibers may be oriented in the width direction of the belt and embedded in the rubber composition (rubber layer) in order to suppress compressive deformation of the belt due to pressure from the pulley (from the viewpoint of improving lateral pressure resistance).

[0108] The proportion of the short fibers may be, for example, 0 to 50 parts by mass (e.g., 20 to 40 parts by mass), preferably 0 to 30 parts by mass (particularly, 0 part by mass) per 100 parts by mass of the rubber component. If the proportion of the short fibers is too high, there is a risk that the adhesion to the tie band or flexibility may decrease.

[0109] Conventional crosslinking agents (or vulcanizing agents) can be used depending on the type of rubber component. Examples include organic peroxides (diacyl peroxides, peroxy esters, dialkyl peroxides, preferably dialkyl peroxides such as 1,3-bis(t-butylperoxyisopropyl)benzene), sulfur-based vulcanizing agents (e.g., powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, sulfur chlorides (sulfur monochloride, sulfur dichloride, etc.), preferably powdered sulfur), and the like. These crosslinking agents (or vulcanizing agents) can be used alone or in combination of two or more. Among these crosslinking agents (or vulcanizing agents), it is preferable to include at least an organic peroxide, as this facilitates improving the adhesive strength (or peel strength) to the tie band. A combination of an organic peroxide and a sulfur-based vulcanizing agent is even more preferable.

[0110] The proportion of the crosslinking agent (or vulcanizing agent) may be selected from a range of, for example, about 1 to 20 parts by mass (e.g., 1.5 to 10 parts by mass), preferably about 2 to 8 parts by mass (e.g., 4 to 7 parts by mass), based on the solid content per 100 parts by mass of the rubber component, depending on the type of crosslinking agent (or vulcanizing agent) and the rubber component. The proportion of the organic peroxide may be, for example, about 0 to 10 parts by mass (e.g., 1 to 8 parts by mass), preferably about 3 to 7 parts by mass, based on the solid content per 100 parts by mass of the rubber component. The proportion of the sulfur-based vulcanizing agent may be, for example, about 0 to 5 parts by mass (e.g., 1 to 3 parts by mass), preferably about 0.3 to 0.7 parts by mass, based on the solid content per 100 parts by mass of the rubber component. When both the organic peroxide and the sulfur-based vulcanizing agent are used in combination, the ratio of the former to the latter (mass ratio) may be, for example, about 80 / 20 to 99 / 1, preferably about 85 / 15 to 95 / 5. If the proportion of the organic peroxide is too low, it may be difficult to improve the heat resistance.

[0111] 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. alkane polyol poly(meth)acrylates such as methyl methacrylate, bismaleimides (aliphatic bismaleimides, for example, alkylene bismaleimides such as N,N'-1,2-ethylene dimaleimide, N,N'-hexamethylene bismaleimide, and 1,6'-bismaleimide-(2,2,4-trimethyl)cyclohexane; arene bismaleimides or aromatic bismaleimides, for example, N,N'-m-phenylene dimaleimide, 4-methyl-1,3-phenylenedimaleimide, 4,4'-diphenylmethane dimaleimide, 2,2-bis[4-(4-maleimidophenoxy)phenyl]propane, 4,4'-diphenylether dimaleimide, 4,4'-diphenylsulfone dimaleimide, and 1,3-bis(3-maleimidophenoxy)benzene). These co-crosslinking agents can be used alone or in combination of two or more. Among these co-crosslinking agents, polyfunctional (iso)cyanurates, polyfunctional (meth)acrylates, and bismaleimides (arene bismaleimides such as N,N'-m-phenylenedimaleimide or aromatic bismaleimides) are preferred, and bismaleimides are often used.

[0112] The proportion of the co-crosslinking agent (crosslinking aid) such as bismaleimides may be, for example, about 0.1 to 15 parts by mass (e.g., 0.5 to 1.5 parts by mass), preferably about 5 to 15 parts by mass (e.g., 7 to 13 parts by mass), calculated as solid content per 100 parts by mass of the rubber component. If the amount of the co-crosslinking agent (crosslinking aid) (particularly bismaleimides) is too small, it may be difficult to improve the mechanical properties.

[0113] Examples of the crosslinking accelerator (or vulcanization accelerator) 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, zinc salt of 2-mercaptobenzothiazole, etc.], , 2-mercaptothiazoline, dibenzothiazyl disulfide (MBTS), 2-(4'-morpholinodithio)benzothiazole, etc.], 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, etc.), dithiocarbamates, xanthogenates, etc. These crosslinking accelerators (or vulcanization accelerators) can be used alone or in combination of two or more. Of these crosslinking accelerators (or vulcanization accelerators), TMTD, CBS, MBTS, etc. are preferred.

[0114] The ratio of the crosslinking accelerator (or vulcanization accelerator) may be, in terms of solid content, for example, 0 to 15 parts by mass (e.g., 0.1 to 10 parts by mass), preferably 0 to 5 parts by mass (e.g., 1 to 4 parts by mass), and more preferably about 0 part by mass, per 100 parts by mass of the rubber component.

[0115] The proportion of the metal oxide (eg, zinc oxide) may be, for example, 1 to 20 parts by mass (eg, 2 to 10 parts by mass), and preferably about 3 to 7 parts by mass, calculated as solid content, per 100 parts by mass of the rubber component.

[0116] The proportion of the softener (oils such as paraffin-based oil) may be, for example, 1 to 30 parts by mass (e.g., 2 to 5 parts by mass), preferably about 5 to 15 parts by mass, calculated as solid content per 100 parts by mass of the rubber component. If the amount of softener (especially oils such as paraffin-based oil) is too small, the adhesion may decrease, and the tie band or outer covering fabric may easily peel off.

[0117] The proportion of the processing agent or processing aid (such as stearic acid) may be, for example, 10 parts by mass or less (e.g., 0 to 10 parts by mass), preferably about 0.1 to 5 parts by mass (e.g., 0.5 to 1.5 parts by mass), calculated as solid content per 100 parts by mass of the rubber component.

[0118] The proportion of the adhesion improver (such as a resorcinol-formaldehyde co-condensate or hexamethoxymethylmelamine) may be, in terms of solid content, for example, 0 to 20 parts by mass (e.g., 0 to 10 parts by mass), preferably 0 to 5 parts by mass, and more preferably about 0 part by mass, per 100 parts by mass of the rubber component.

[0119] Examples of antioxidants include benzimidazole-based antioxidants (2-mercaptobenzimidazole (MBI), 2-mercaptomethylbenzimidazole, or metal salts thereof such as zinc salts), and aromatic secondary amine-based antioxidants (for example, 4,4'-dioctyldiphenylamine (ODPA), 4,4'-bis(α,α-dimethylbenzyl)diphenylamine (DCD)). These antioxidants can be used alone or in combination. Of these, MBI and ODPA are preferred.

[0120] The proportion of the antioxidant may be, for example, 0 to 15 parts by mass (eg, 0.1 to 1 part by mass), and preferably about 2 to 4 parts by mass, calculated as solid content, per 100 parts by mass of the rubber component.

[0121] The average thickness of the tension rubber layer may be, for example, about 0.5 to 10 mm (e.g., 0.5 to 1.5 mm), preferably about 0.6 to 5 mm, and more preferably about 0.7 to 3 mm (particularly 1 to 2 mm), and may be adjusted appropriately depending on the number of layers of the outer covering fabric, etc.

[0122] (Compressed Rubber Layer) The compressed rubber layer may be formed of a vulcanized or crosslinked rubber composition (a crosslinked rubber composition containing a rubber component) that is commonly used as a rubber composition for wrapped V-belts.

[0123] Examples of the rubber component in the crosslinked rubber composition that forms the compressed rubber layer include the same rubber components as those exemplified in the section on the tensioned rubber layer, including preferred embodiments thereof. The rubber component in the crosslinked rubber composition that forms the compressed rubber layer is preferably the same type (particularly the same) of rubber component as the rubber component in the crosslinked rubber composition that forms the tensioned rubber layer.

[0124] Furthermore, the crosslinked rubber composition forming the compression rubber layer may or may not contain conventional additives in addition to the rubber component, as necessary. Examples of the additives include the same additives as those exemplified in the section on the tension rubber layer, including preferred embodiments thereof.

[0125] The crosslinked rubber compositions forming the compressed rubber layer and the tensioned rubber layer may be the same or different. When the crosslinked rubber composition forming the compressed rubber layer contains short fibers, the short fibers may be oriented in the belt width direction and embedded in the rubber composition (rubber layer) to suppress compressive deformation of the belt due to pressure from the pulleys (from the viewpoint of improving lateral pressure resistance).

[0126] The compressed rubber layer may be a single layer, or may be formed of multiple layers (for example, two or more layers, preferably about two to three layers) as needed. When the compressed rubber layer is formed of multiple layers, from the viewpoint of productivity, it may be preferably formed of two layers, with a first compressed rubber layer on the outer circumferential side of the belt [on the core layer (adhesive rubber layer) side] and a second compressed rubber layer on the inner circumferential side. When formed of multiple layers, the crosslinked rubber compositions forming the respective compressed rubber layers may be the same or different from each other, and preferably the rubber components in the crosslinked rubber compositions may be the same (particularly the same). From the viewpoint of improving lateral pressure resistance, the first compressed rubber layer on the outer peripheral side of the belt [on the core layer (adhesive rubber layer) side] may be formed of a crosslinked rubber composition having a higher hardness than the second compressed rubber layer on the inner peripheral side. Specifically, the hardness of each compressed rubber layer may be adjusted by adjusting the type and amount of additives in the crosslinked rubber composition [for example, filler, short fiber, crosslinking agent (or vulcanizing agent), co-crosslinking agent or crosslinking aid (or vulcanization aid), crosslinking accelerator (or vulcanization accelerator), metal oxide, softener, processing agent or processing aid, plasticizer, etc.].

[0127] The average thickness of the entire compressed rubber layer may be, for example, about 1 to 12 mm, preferably about 2 to 10 mm, and more preferably about 3 to 8 mm (particularly about 4.5 to 6 mm), and may be adjusted appropriately depending on the number of outer cover fabric layers, etc. When the compressed rubber layer has a two-layer structure, the average thickness of the first compressed rubber layer on the outer periphery of the belt may be, for example, about 10 to 90% (e.g., 10 to 60%), and preferably about 15 to 50% (e.g., 20 to 40%) of the average thickness of the entire compressed rubber layer.

[0128] (Core Layer, Adhesive Rubber Layer) The core layer may include a core, and may be formed solely of a core, as described above. In the present application, when the core layer is formed solely of a core, the cores arranged at intervals in the belt body are referred to as the core layer, and this core layer includes not only a form in which the core is arranged at the interface between the tension rubber layer and the compression rubber layer, but also a form in which a part or all of the core arranged at the interface between the tension rubber layer and the compression rubber layer is embedded in the tension rubber layer or the compression rubber layer during the manufacturing process.

[0129] Furthermore, the core layer may be a core layer (adhesive rubber layer) formed of a crosslinked (vulcanized) rubber composition containing a core, from the viewpoint of suppressing interlayer delamination and improving belt durability. A core layer formed of a crosslinked rubber composition containing a core is usually called an adhesive rubber layer, and the core is embedded in a layer formed of a crosslinked rubber composition containing a rubber component. The adhesive rubber layer is interposed between the tension rubber layer and the compression rubber layer, and bonds the tension rubber layer, the compression rubber layer, and the core. In this application, the core layer (adhesive rubber layer) includes not only a form in which the entire core is embedded in the adhesive rubber layer, but also a form in which the core is disposed at the interface between the adhesive rubber layer and the tension rubber layer or the compression rubber layer during the manufacturing process.

[0130] Core The core contained in the core layer is preferably a cord (twisted cord) arranged at a predetermined interval in the belt width direction. The cord is arranged extending in the length direction of the belt, and is usually arranged in parallel with the length direction of the belt at a predetermined pitch. When the core (cord) is embedded in the adhesive rubber layer, it is sufficient that a part of it is embedded in the adhesive rubber layer. From the viewpoint of improving durability, the cord may be embedded in the adhesive rubber layer (the entire cord is completely embedded in the adhesive rubber layer).

[0131] Examples of fibers constituting the core wire include the fibers exemplified as fibers constituting the fabric in the section on the outer covering fabric. These fibers can be used alone or in combination of two or more.

[0132] Among these fibers, C fibers such as ethylene terephthalate and ethylene-2,6-naphthalate are preferred in terms of high modulus. ２－４ Alkylene-C ６－１４ Synthetic fibers such as polyester fibers (polyalkylene arylate fibers) and polyamide fibers (aramid fibers, etc.) having arylate as the main structural unit, 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 polyamide fibers such as aramid fibers being more preferred.

[0133] These fibers may be used in the form of a multifilament yarn containing multiple filaments. The fineness of the multifilament yarn may be, for example, about 1,000 to 3,000 dtex (e.g., 1,200 to 2,000 dtex). The multifilament yarn may contain, for example, about 100 to 3,000 filaments (e.g., 500 to 2,000 filaments), preferably about 700 to 1,300 filaments.

[0134] The core wire can typically be a twisted cord (e.g., ply twist, single twist, Lang twist, etc., preferably ply twist) using multifilament yarn. The average wire diameter of the core wire (diameter of the twisted cord) may be, for example, 0.5 to 3 mm, preferably 0.6 to 2.5 mm, and more preferably about 0.7 to 2 mm. The total fineness of the twisted cord may be, for example, about 10,000 to 50,000 dtex (e.g., 22,000 to 28,000 dtex). The twisted cord may contain, for example, about 1,000 to 30,000 filaments (e.g., 5,000 to 25,000 filaments), preferably about 10,000 to 20,000 filaments (e.g., 12,000 to 18,000 filaments). The twist multiplier of the first twisted yarn of the twisted cord may be, for example, about 2 to 4 (for example, 2.5 to 3.5), and the twist multiplier of the second twisted yarn may be, for example, about 2 to 4 (for example, 2.5 to 3.5).

[0135] When the cord is embedded in the adhesive rubber layer, it 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 the crosslinked rubber composition that forms the adhesive rubber layer. Examples of the adhesive component (or surface treatment agent) used in the adhesive treatment include the same components as those exemplified in the section on the outer covering fabric. These may be used alone or in combination of two or more, and the cord may be treated multiple times sequentially with the same or different adhesive components.

[0136] The adhesive rubber layer may be formed from a vulcanized or crosslinked rubber composition (a crosslinked rubber composition containing a rubber component) that is commonly used as a rubber composition for wrapped V-belts.

[0137] Examples of the rubber component in the crosslinked rubber composition that forms the adhesive rubber layer include the same rubber components as those exemplified in the section on the tension rubber layer, including preferred embodiments thereof. The rubber component in the crosslinked rubber composition that forms the adhesive rubber layer is preferably the same type (particularly the same) of rubber component as the rubber component in the crosslinked rubber composition that forms the tension rubber layer and / or compression rubber layer.

[0138] Furthermore, the crosslinked rubber composition forming the adhesive rubber layer may or may not contain conventional additives in addition to the rubber component, as necessary. Examples of the additives include the same additives as those exemplified in the section on the tension rubber layer, including preferred embodiments thereof.

[0139] The average thickness of the adhesive rubber layer may be, for example, about 0.2 to 5 mm (e.g., 0.3 to 3 mm), preferably about 0.3 to 2 mm (e.g., 0.5 to 1.5 mm), and may be adjusted appropriately depending on the number of layers of the outer covering fabric, etc.

[0140] (Reinforcing Fabric Layer) The belt main body may include a reinforcing fabric layer laminated on the inner circumferential surface (inner peripheral surface) side of the compressed rubber layer, as needed. That is, each wrapped V-belt portion may or may not further include a reinforcing fabric layer between the inner circumferential surface (inner peripheral surface) of the compressed rubber layer and the outer cover fabric, as needed.

[0141] The reinforcing fabric layer may be formed, for example, from a conventional fabric, and the fabric may be the same as the fabrics exemplified in the section on the outer covering fabric, including preferred embodiments thereof.

[0142] The fabric forming the reinforcing fabric layer may be subjected to a conventional adhesive treatment (or surface treatment) [e.g., treatment with a treatment solution containing an adhesive component] to improve adhesion to the compressed rubber layer and the outer covering fabric. Examples of adhesive components (or surface treatment agents) used in the adhesive treatment include the same components as those exemplified in the section on the outer covering fabric. These may be used alone or in combination, and treatments may be performed multiple times with the same or different adhesive components. A preferred fabric is one having a rubber component attached thereto. For example, this may be a fabric that has been subjected to an adhesive treatment such as soaking (immersing) the fabric in a rubber paste prepared by dissolving a rubber composition containing a rubber component in a solvent, or rubbing (rubbing) the solid rubber composition into the fabric. The rubber composition may be the same as the rubber composition described in the section on the outer covering fabric, including preferred embodiments. The adhesive treatment may be applied to at least one surface of the fabric, preferably the surface that comes into contact with the compressed rubber layer, and particularly preferably both surfaces.

[0143] The average thickness of the reinforcing fabric layer is, for example, about 0.4 to 2 mm, preferably about 0.5 to 1.4 mm, and more preferably about 0.6 to 1.2 mm. If the reinforcing fabric layer is too thin, the effect of improving abrasion resistance may be reduced, and if it is too thick, the flexibility of the belt may be reduced.

[0144] [Tie Band (Connecting Member)] The tie band can be a tie band of a conventional connected V-belt, and examples thereof include a rubber composition (a cross-linked rubber composition containing a rubber component), a woven fabric such as canvas, a fiber structure (or fabric) such as a blind (woven blind fabric), or a net (a net-like structure or mesh), or a combination thereof. It is preferable that the tie band contain at least a fiber, since this can effectively prevent the wrapped connected V-belt from breaking.

[0145] When a tie band contains fibers, the adhesive strength (peeling strength) with the wrapped V-belt portion is usually prone to decrease. However, in the wrapped connected V-belt of the present invention, high adhesive strength can be ensured with the uncovered area on the outer surface of the wrapped V-belt portion, so that both adhesiveness and wheel breakage resistance can be achieved, and the durability of the wrapped connected V-belt can be effectively improved.

[0146] The fiber-containing tie band may be, for example, a rubber composition containing short fibers (e.g., a rubber composition containing the rubber component and short fibers exemplified in the section on the tension rubber layer), but preferably contains at least a fiber structure (particularly, canvas, sudare, etc.). Therefore, the tie band may have at least a connecting reinforcing layer containing the fiber structure, and may also have a protective layer laminated on the outer periphery of the connecting reinforcing layer, as necessary.

[0147] (Connecting Reinforcement Layer) The connecting reinforcement layer may contain at least the above-mentioned fiber structure (or fabric), and the fiber structure may be used alone or in combination of two or more. Among the fiber structures, a woven sudare fabric is preferred because it can simultaneously suppress breakage and provide flexibility in the belt length direction, and also has an excellent balance with productivity.

[0148] Among the various types of sudare fabrics, sudare fabrics containing a plurality of filaments extending in the belt width direction are preferred, as they can further improve resistance to tensile forces acting in the belt width direction, and it is particularly preferred to use sudare fabrics 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 plurality of first filaments and extending in a direction intersecting the belt width direction.

[0149] In the present application, the filaments extending in the belt width direction refer to filaments extending substantially parallel to the belt width direction. Furthermore, "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 about 3° or less (e.g., 0 to 1°, particularly about 0°).

[0150] The yarn density of the first filament (number of yarns per 5 cm in the belt length direction) is, for example, 10 to 300 yarns / 50 mm, preferably 50 to 200 yarns / 50 mm, further preferably 80 to 180 yarns / 50 mm, further preferably 100 to 150 yarns / 50 mm, and most preferably 110 to 130 yarns / 50 mm.

[0151] The thread density of the second filamentous body is, for example, 1 to 30 threads / 50 mm, preferably 2 to 10 threads / 50 mm, further preferably 2 to 8 threads / 50 mm, further preferably 3 to 7 threads / 50 mm, and most preferably 4 to 6 threads / 50 mm.

[0152] Examples of fibers constituting the first and second filaments include the fibers exemplified in the section on the outer cover fabric. Of these fibers, polyester fibers and polyamide fibers are preferred for the first filaments, with aliphatic polyamide fibers such as polyamide 66 being particularly preferred. Cellulose fibers are preferred for the second filaments, with cotton fibers being particularly preferred.

[0153] When the first filament is a polyester fiber or a polyamide fiber, the fineness of the first filament (total fineness in the case of a multifilament yarn, etc.) is, for example, 100 to 1000 dtex, preferably 200 to 800 dtex, and more preferably 400 to 600 dtex.

[0154] When the second filaments are cellulose fibers such as cotton fibers, the thickness (count) of the second filaments is, for example, about 5 to 100 count, preferably about 10 to 80 count, and more preferably about 30 to 50 count.

[0155] 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) or the like. Examples of the adhesive component (or surface treatment agent) used in the adhesive treatment include the same components as those exemplified in the section on the outer covering fabric. These may be used alone or in combination of two or more, and the same or different adhesive components may be used multiple times in succession.

[0156] The average thickness of the fiber structure is, for example, about 0.1 to 0.5 mm, and preferably about 0.2 to 0.4 mm. If the thickness of the fiber structure is too thin, there is a risk of delamination or breakage, whereas if it is too thick, there is a risk of the flexibility of the belt decreasing.

[0157] The connecting reinforcement layer may be formed of a fiber structure (for example, a fabric that has been subjected to an adhesive treatment with a rubber component or the like), but from the viewpoints of not only suppressing peeling of the fiber structure but also suppressing interlayer (interlayer peeling with the wrapped V-belt portion and / or the protective layer) peeling and preventing breakage (including suppressing the propagation of defects), it is preferable that the fiber structure be sandwiched between a rubber composition containing a rubber component (rubber sandwiched between the connecting reinforcement layer) (an embodiment in which the fiber structure is embedded in a crosslinked rubber composition).

[0158] Examples of the rubber component constituting the crosslinked rubber composition of the link reinforcement layer include the same rubber components as those exemplified in the section on the tension rubber layer, including preferred embodiments thereof. The rubber component in the crosslinked rubber composition forming the link reinforcement layer is preferably the same type (e.g., the same) of rubber component as the rubber component in the crosslinked rubber composition forming the tension rubber layer and / or compression rubber layer, and preferably contains, for example, an ethylene-α-olefin elastomer such as EPDM.

[0159] The ethylene content (proportion of ethylene units) in the ethylene-α-olefin elastomer may be 25% by mass or more (e.g., 30 to 70% by mass), preferably about 35 to 55% by mass (e.g., 40 to 50% by mass). If the ethylene content is too high, there is a risk that processability and crack resistance may decrease.

[0160] The ratio (mass ratio) of ethylene to α-olefin is, for example, the former / the latter = 30 / 70 to 70 / 30, preferably 40 / 60 to 60 / 40, and more preferably 45 / 55 to 55 / 45.

[0161] The diene content (particularly, the ethylidene norbornene content) of the ethylene-α-olefin elastomer (particularly, an ethylene-α-olefin-diene terpolymer such as EPDM) is, for example, 0.1 to 15 mass%, preferably 1 to 12 mass% (e.g., 5 to 10 mass%), and more preferably 6 to 9 mass% (e.g., 7 to 8 mass%). If the diene content is too high, there is a risk that high heat resistance cannot be ensured. If the diene content is too low, there is a risk that processability and crack resistance will decrease.

[0162] The Mooney viscosity [ML(1+4)100°C] of the uncrosslinked ethylene-α-olefin elastomer may be, for example, about 10 to 85 (e.g., 30 to 60), preferably about 35 to 55 (e.g., 40 to 50). If the Mooney viscosity is too high, there is a risk that processability and crack resistance may decrease.

[0163] In this application, the Mooney viscosity [ML(1+4)100°C] can be measured by a method in accordance with JIS K 6300-1 (2013), and the test conditions are as follows: an L-shaped rotor is used, the test temperature is 100°C, preheating is 1 minute, and the rotor operation time is 4 minutes. The Mooney viscosity is used as an index of the fluidity (ease of processing) of rubber, measured by filling an uncrosslinked ethylene-α-olefin elastomer in a cavity so that it is in contact with a rotor having grooves on its surface, and measuring the torque required to rotate the rotor.

[0164] The crosslinked rubber composition of the link reinforcement layer may or may not contain conventional additives in addition to the rubber component, as necessary. Examples of additives include the same additives as those exemplified in the section on the tension rubber layer, and preferably include fillers, crosslinking agents (or vulcanizing agents), crosslinking accelerators (or vulcanization accelerators), metal oxides, processing agents or processing aids, adhesion improvers, antioxidants, etc. These may be used alone or in combination of two or more.

[0165] The filler in the cross-linked rubber composition of the link reinforcement layer is preferably a reinforcing filler such as carbon black (hard carbon such as HAF) or silica. The proportion of the filler (particularly the reinforcing filler) may be, for example, 30 to 80 parts by mass, preferably 40 to 70 parts by mass (e.g., 50 to 60 parts by mass) per 100 parts by mass of the rubber component. The proportion of the reinforcing filler may be, for example, 50% by mass or more, preferably 75% by mass or more (e.g., 80% by mass or more), more preferably 90% by mass or more, or even 100% by mass, based on the total filler. The proportion of carbon black (particularly hard carbon) may be, for example, 20 to 50 parts by mass (e.g., 25 to 45 parts by mass), preferably 30 to 40 parts by mass, per 100 parts by mass of the rubber component. The proportion of silica may be, for example, 5 to 40 parts by mass (e.g., 8 to 35 parts by mass), preferably 10 to 30 parts by mass (e.g., 15 to 25 parts by mass) per 100 parts by mass of the rubber component. When both carbon black (particularly hard carbon) and silica are contained, the ratio of the two may be, for example, the former / latter (mass ratio) = 45 / 55 to 80 / 20, preferably 55 / 45 to 70 / 30.

[0166] The cross-linking agent (or vulcanizing agent) in the cross-linked rubber composition of the link reinforcement layer is preferably a sulfur-based vulcanizing agent. The proportion of the cross-linking agent (or vulcanizing agent) (particularly the sulfur-based vulcanizing agent) may be, for example, about 0.1 to 3 parts by mass (e.g., 0.3 to 2 parts by mass), preferably about 0.5 to 1.5 parts by mass, calculated as solid content, per 100 parts by mass of the rubber component, depending on the type of cross-linking agent (or vulcanizing agent) and the rubber component.

[0167] The cross-linking accelerator (or vulcanization accelerator) in the cross-linked rubber composition of the link reinforcing layer is preferably MBTS, etc. The proportion of the cross-linking accelerator (or vulcanization accelerator) may be, for example, about 0.1 to 3 parts by mass (e.g., 0.3 to 2 parts by mass), preferably about 0.5 to 1.5 parts by mass, calculated as solid content, per 100 parts by mass of the rubber component.

[0168] The proportion of the metal oxide (such as zinc oxide) in the cross-linked rubber composition of the link reinforcement layer may be, for example, 1 to 20 parts by mass (e.g., 2 to 10 parts by mass), preferably about 3 to 7 parts by mass, calculated as solid content per 100 parts by mass of the rubber component.

[0169] The proportion of the processing agent or processing aid (such as stearic acid) in the cross-linked rubber composition of the linking reinforcement layer may be, for example, 10 parts by mass or less (e.g., 0 to 10 parts by mass), preferably about 0.1 to 5 parts by mass (e.g., 0.5 to 1.5 parts by mass), calculated as solid content per 100 parts by mass of the rubber component.

[0170] The proportion of the adhesion improver (such as a resorcinol-formaldehyde co-condensate or hexamethoxymethylmelamine) in the crosslinked rubber composition of the linking reinforcing layer may be, for example, about 0.1 to 20 parts by mass (e.g., 1 to 10 parts by mass), preferably about 2 to 8 parts by mass (e.g., 3 to 5 parts by mass), calculated as solid content per 100 parts by mass of the rubber component.

[0171] The antioxidant in the crosslinked rubber composition of the link reinforcement layer is preferably DCD. The proportion of the antioxidant may be, for example, 0.1 to 15 parts by mass (e.g., 1 to 3 parts by mass), preferably about 1.5 to 2.5 parts by mass, calculated as solid content, per 100 parts by mass of the rubber component.

[0172] The connecting reinforcing layer may be used alone (single layer) or in combination of two or more kinds, but is preferably used alone (single layer).

[0173] The average thickness of the connecting reinforcing layer is, for example, 0.4 to 1.4 mm, and preferably about 0.5 to 1 mm. If the fabric layer is too thin, there is a risk of delamination or breakage, whereas if it is too thick, there is a risk of the flexibility of the belt being reduced.

[0174] (Protective layer) The tie band (connecting member) may be formed of only the connecting reinforcement layer, but may also be provided with a protective layer laminated on top of the connecting reinforcement layer (on the outer peripheral surface side of the belt or as the outermost layer) in order to effectively prevent damage to the fiber structure in the connecting reinforcement layer (for example, damage caused by foreign matter from the back surface of the belt).

[0175] The protective layer may be formed of a rubber sheet of a conventional crosslinked rubber composition (e.g., a rubber sheet of a rubber composition containing short fibers) or a conventional fabric (e.g., the fabrics exemplified in the section on the outer covering fabric). These protective layers may be used alone or in combination of two or more. Of these protective layers, a protective layer formed of a crosslinked rubber composition is preferred.

[0176] Examples of the rubber component in the crosslinked rubber composition of the protective layer include the same rubber components as those exemplified in the section on the tension rubber layer, including preferred embodiments thereof. The rubber component in the crosslinked rubber composition forming the protective layer is preferably the same type (particularly the same) of rubber component as the rubber component in the crosslinked rubber composition forming the tension rubber layer.

[0177] Furthermore, the crosslinked rubber composition forming the protective layer may or may not contain conventional additives in addition to the rubber component, as necessary. Examples of the additives include the same additives as those exemplified in the section on the tension rubber layer, including preferred embodiments thereof.

[0178] The crosslinked rubber compositions forming the protective layer and the tension rubber layer may be the same or different. When the crosslinked rubber composition forming the protective layer contains short fibers, the short fibers may be oriented in the belt width direction and embedded in the rubber composition (rubber layer) from the viewpoint of improving wheel breakage resistance and improving abrasion resistance when the back surface of the belt comes into contact with a flange portion of an idler pulley, a tensioner, or the like.

[0179] The average thickness of the protective layer is, for example, about 0.4 to 2 mm, preferably about 0.8 to 1.8 mm, and more preferably about 1 to 1.5 mm. If the protective layer is too thin, the effect of suppressing damage to the fiber structure may be reduced, and if it is too thick, the flexibility of the belt may be reduced.

[0180] The tie band (connecting member) may have a plurality of protective layers (for example, two or three layers) as needed, but preferably has one layer.

[0181] [Method for manufacturing wrapped connected V-belt] The wrapped connected V-belt is obtained by manufacturing uncrosslinked (unvulcanized) wrapped V-belt portions (wrapped V-belt portion precursors) and then carrying out a connecting step in which the resulting multiple unvulcanized wrapped V-belt portions (wrapped V-belt portion precursors) are connected with tie bands (tie band precursors).

[0182] The uncrosslinked (unvulcanized) wrapped V-belt portion (wrapped V-belt portion precursor) can be produced by, for example, the methods described in Japanese Patent Application Laid-Open No. 6-137381 and WO2015 / 104778. Specifically, the unvulcanized compression rubber layer sheet obtained by rolling is cut and set on a mantle, an unvulcanized first adhesive rubber layer sheet is wrapped around the compression rubber layer sheet, a core is wrapped around the wrapped first adhesive rubber layer sheet, and then an unvulcanized second adhesive rubber layer sheet and an unvulcanized tension rubber layer sheet are wrapped around the wrapped core in that order in a winding process; a cutting process in which the resulting annular laminate is cut (sliced ​​into rings) on the mantle; a skiving process in which the cut annular laminate is placed around a pair of pulleys and cut into a V shape while rotating (skiving process); and an outer cover fabric covering process (covering process or cover wrapping process) in which the periphery of the resulting unvulcanized belt main body (belt main body precursor) is covered with an outer cover fabric precursor [for example, an outer cover fabric (fabric) having an uncrosslinked rubber composition attached] to obtain an unvulcanized wrapped V-belt portion (wrapped V-belt portion precursor).

[0183] In the winding process, if the compressed rubber layer is made of multiple layers, a laminated sheet made by stacking multiple compressed rubber layer sheets may be cut and set on the mantle, and only one of the first and second adhesive rubber layer sheets may be wound, or neither may be wound (it is also possible not to form an adhesive rubber layer).

[0184] The method for producing a wrapped V-belt of the present invention includes at least a covering step of covering a belt body precursor with an outer cover fabric precursor to form a wrapped V-belt precursor, and a connecting step of connecting the outer surfaces of the multiple wrapped V-belt precursors obtained in the covering step with tie-band precursors [e.g., tie-bands containing fibers (particularly a fiber structure) and an uncrosslinked rubber composition], in which the covering step covers at least the inner and both side surfaces of the belt body precursor, and leaves at least a partial region of the outer surface (the uncovered region) uncovered, and does not necessarily include a removal step (described in Patent Documents 2 and 3) of cutting or removing the outer cover fabric precursor covering the outer surface of the wrapped V-belt precursor obtained in the covering step. This allows for the omission of a step, making it possible to produce a wrapped V-belt with excellent wear resistance and reduced tie-band peeling at high productivity and low cost.

[0185] In addition, the manufacturing method of the present invention can easily and efficiently manufacture a wrapped coupled V-belt in which the entire outer peripheral surface of the wrapped V-belt portion is an uncoated region (an embodiment that does not include a covered region). However, it is preferable to manufacture a wrapped coupled V-belt having both a covered region and an uncoated region, as this allows for even higher productivity.

[0186] In the covering step, the inner circumferential surface, both side surfaces, and at least one side of the outer circumferential surface (the region corresponding to the covered region, preferably both sides) of the belt body precursor may be covered with a continuous (continuous) outer cover fabric precursor. The width of the outer cover fabric precursor may be shorter than the perimeter of the cross-section perpendicular to the longitudinal direction of the belt body precursor (i.e., the total length of the inner circumferential surface, both side surfaces, and the outer circumferential surface in the cross-section), or may be longer than the total length of the inner circumferential surface and both side surfaces in the cross-section, depending on the area ratio of the uncovered region, etc. The belt body precursor may be covered with the width direction of this outer cover fabric precursor oriented perpendicular to the belt longitudinal direction (the length direction of the outer cover fabric precursor oriented in the belt longitudinal direction).

[0187] Conventionally, when a belt body precursor is covered with an outer covering fabric precursor, for example, as shown in FIG. 2 , the belt body precursor is wound around two pulleys and rotated (running), and a roll of the outer covering fabric precursor is brought into contact with (abut against) the outer surface of the rotating belt body precursor while being fed out. A roller is then pressed against the outer covering fabric precursor that is in contact with the outer surface to conform to the shape of the belt body precursor (while feeding out the outer covering fabric precursor, a roller is applied from the outside to roll it into a cylindrical shape like a pipe conveyor, so as to wrap around the belt body precursor), and the outer covering fabric precursor is then overlapped on the inner side to form a wrapped V-belt precursor.

[0188] In contrast, in the present invention, the belt body precursor is rotated (traveled) between two pulleys with the inner and outer sides reversed (with the wide side facing the inner side and the narrow side facing the outer side), and can be covered with an outer cover fabric precursor of a predetermined width (a continuous outer cover fabric precursor having a width shorter than the perimeter of the cross-sectional shape perpendicular to the longitudinal direction of the belt body precursor, as described above). That is, the outer cover fabric precursor of a predetermined width is brought into contact with the narrow outer surface of the rotating belt body precursor (the surface that will become the inner surface of the wrapped V-belt), and pressed with a roller to conform to the shape of the belt body precursor in the same manner as in the past, thereby covering both side surfaces and the wide inner surface (the surface that will become the outer surface of the wrapped V-belt). However, because the width of the outer cover fabric precursor is shorter than the perimeter, at least one side of the wide inner surface (the surface that will become the outer surface of the wrapped V-belt) is covered, and an uncovered area (corresponding to the uncovered area) is formed.

[0189] As described above, when a wrapped V-belt precursor is manufactured using a seamless outer covering fabric precursor, with the entire outer periphery of the belt uncovered, it is considered difficult to align the outer covering fabric precursor (aligning both widthwise ends of the outer covering fabric precursor with both ends of the outer peripheral surface of the belt body precursor) for the following reasons. First, the outer covering fabric precursor becomes sticky due to the adhesive treatment, so once it is brought into contact with the belt body precursor, its position cannot be corrected. In addition, the belt body precursor is soft because it is an uncrosslinked rubber composition, and is prone to becoming distorted during a skiving process or the like. Therefore, when the belt body precursor and the outer covering fabric precursor are brought into contact with each other, it is difficult to make the belt body precursor run straight (it tends to meander), and misalignment with the outer covering fabric precursor is likely to occur. Furthermore, during the crosslinking molding process (crosslinking molding step) described below, the rubber composition may flow within a mold due to pressure or the like, causing misalignment. Therefore, when attempting to manufacture a wrapped V-belt in which the entire outer periphery of the belt is an uncovered area (the proportion of uncovered area is 100%), misalignment can easily result in portions of the belt length where the side is not covered by the outer sheath fabric, which tends to increase the reject rate.

[0190] However, by adjusting the width of the outer cover fabric precursor to the predetermined length and covering the inner circumferential surface and both side surfaces of the belt while folding the end of the outer cover fabric precursor into the side of the outer circumferential surface on at least one side (preferably both sides), as in the above-mentioned covering step, not only can the occurrence of portions of the belt side surfaces that are not covered by the outer cover fabric be effectively prevented, but the removal step can be eliminated and no material waste occurs, making it possible to simply and efficiently manufacture a wrapped V-belt precursor with high productivity. Moreover, in the obtained wrapped V-belt precursor, not only can the uncovered regions improve adhesion to the tie bands, but also, because a covered region is formed on at least one side (preferably both sides) of the outer circumferential surface in a form that is folded in from the side, peeling of the outer cover fabric from the boundary with the tie band can be effectively prevented.

[0191] When the outer covering fabric precursor is used for endless covering, one end and the other end in the longitudinal direction of the outer covering fabric precursor may be adjacent to each other without overlapping, or may be partially overlapped, and preferably, both longitudinal ends may be partially overlapped to form an endless covering.

[0192] The wrapped V-belt portion precursor obtained in the covering step may be connected to a tie band precursor (e.g., a tie band containing an uncrosslinked rubber composition) by a conventional method (connecting step). For example, a plurality of unvulcanized wrapped V-belt portions (wrapped V-belt portion precursors) are fitted into a groove having an inverted trapezoidal cross section formed in a cylindrical or annular lower vulcanization mold, and then the tie band precursor is set on the radially outer portion. In setting the tie band precursor, the tie band precursor is wrapped around a plurality of unvulcanized wrapped V-belt portions arranged in the width direction in the circumferential direction. The tie band precursor and the plurality of unvulcanized wrapped V-belt portions (wrapped V-belt portion precursors) set as described above are subjected to a crosslinking molding process (vulcanization process) [crosslinking molding process (vulcanization process)] in which they are crosslinked or vulcanized while being sandwiched between an upper vulcanization mold and a lower vulcanization mold and pressurized. This crosslinking molding process (vulcanization process) forms a crosslinked sleeve (vulcanized sleeve) in which a plurality of wrapped V-belt portions are connected and bonded with the tie bands. The crosslinked sleeve (vulcanized sleeve) thus formed is cut to a predetermined width to form a wrapped joined V-belt having a predetermined number of wrapped V-belt portions.

[0193] In the crosslinking molding treatment (vulcanization treatment), the crosslinking (vulcanization) temperature can be selected depending on the type of rubber component and is, for example, about 120 to 200°C, preferably about 150 to 180°C. The pressure in the crosslinking molding treatment (vulcanization treatment) may be, for example, about 1 to 2 MPa, preferably about 1 to 1.5 MPa. Note that the short fibers in each rubber layer sheet can be aligned (oriented) in the rolling direction by, for example, rolling the sheet with a calender roll.

[0194] The tie band precursor and each uncrosslinked (unvulcanized) wrapped V-belt portion (wrapped V-belt portion precursor) are bonded to each other, for example, by an adhesive component attached to the tie band precursor or the outer covering fabric precursor of the covered region by an adhesive treatment, or by the exposed stretch rubber layer of the uncovered region. For example, when a fabric subjected to friction (rubbing) treatment with a solid rubber composition is used as the tie band, the tie band precursor, the outer covering fabric precursor of the covered region, and the exposed stretch rubber layer of the uncovered region are bonded to each other by a crosslinking (vulcanization) reaction of the friction rubber composition. That is, the process of setting the tie band precursor to the unvulcanized wrapped V-belt portion includes an uncrosslinked (unvulcanized) belt bonding step of bonding multiple unvulcanized wrapped V-belt portions to each other via tie bands as connecting portions. The unvulcanized belt bonding step is not limited to this method, and the tie band may be formed by wrapping multiple layers of tie-band rubber sheets (e.g., sheets for connecting reinforcing layers, sheets for protective layers, laminates thereof, etc.).

[0195] The number of wrapped V-belt portions in the wrapped coupled V-belt may be two or more, for example, 2 to 10, preferably 2 to 8, and more preferably 2 to 6. Adjacent wrapped V-belt portions may be aligned parallel to one another in the belt length direction, and are not limited to the arrangement in which they are spaced apart as shown in FIG. 4 , and may be aligned without any spacing. From the standpoint of productivity, it is preferable to space adjacent wrapped V-belt portions. The spacing between adjacent wrapped V-belt portions is, for example, 1.7 to 4.3 mm, preferably 2 to 4.1 mm, and more preferably 2.3 to 3.9 mm. The spacing between wrapped V-belt portions refers to the spacing on the outer circumferential surface of the belt. The tie bands may be used as long as they can connect the wrapped V-belt portions, and are not limited to the arrangement in which they are connected by contacting the entire outer circumferential surface of each wrapped V-belt portion and integrating it with the entire surface as shown in FIG. 4 , and the outer circumferential surface of the wrapped V-belt portion may have a region that does not contact the tie band. From the viewpoint of belt durability, it is preferable that the entire outer peripheral surface of each wrapped V-belt portion be in contact with and integrated with the tie band.

[0196] The wrapped V-belt may be used in a high-load, long-span (long center-to-center distance) layout such as a large-scale agricultural machine, etc. The width of the outer circumferential belt surface of each wrapped V-belt portion may be, for example, about 15 to 60 mm, and the thickness of each wrapped V-belt portion may be, for example, 10 to 20 mm (e.g., 10 to 15 mm).

[0197] The overall belt length of the wrapped coupled V-belt may be, for example, 50 inches or more, 200 inches (508 cm) or more, or about 220 to 500 inches.

[0198] Since the wrapped coupled V-belt is suitable for a long span layout, the maximum span length (the distance between the axes of the pulleys) may be 1000 mm or more, for example, about 2000 to 5000 mm.

[0199] The wrapped coupled V-belt of the present invention is suitable for high-load applications and is therefore suitable for high-horsepower machines, and the load (reference transmission capacity) applied to one wrapped V-belt portion may be 10 PS or more, preferably 20 PS or more, and more preferably 22 PS or more (for example, approximately 22 to 30 PS).

[0200] The wrapped V-belt of the present invention has excellent adhesion (tightness) between the wrapped V-belt portion and the tie band. The peel force (or adhesive strength) between the wrapped V-belt portion and the tie band may be, for example, about 50 to 150 N / cm (e.g., 60 to 130 N / cm), preferably about 70 to 125 N / cm (e.g., 80 to 122 N / cm), and more preferably about 90 to 120 N / cm (e.g., 95 to 120 N / cm).

[0201] In the present application, the peel strength (or adhesive strength) between the wrapped V-belt portion and the tie band can be measured by the method described in the examples.

[0202] The wrapped V-belt of the present invention has excellent wear resistance. The wear rate of the wrapped V-belt before and after running under specified conditions may be, for example, about 0.5 to 2% (e.g., 0.7 to 1.7%), preferably about 0.8 to 1.5% (e.g., 0.9 to 1.4%), and more preferably about 0.95 to 1.3% (e.g., 1 to 1.2%).

[0203] In the present application, the wear rate of the wrapped coupled V-belt can be measured by the method described in the examples.

[0204] The wrapped V-belt of the present invention has excellent resistance to side pressure. The ride-out change of the wrapped V-belt may be, for example, 0.3 to 0.85 mm (e.g., 0.4 to 0.75 mm), preferably 0.43 to 0.7 mm (e.g., 0.45 to 0.65 mm), more preferably 0.48 to 0.6 mm (e.g., 0.49 to 0.55 mm), and particularly preferably 0.5 to 0.52 mm.

[0205] In the present application, the ride-out change amount of the wrapped coupled V-belt can be measured by the method described in the examples.

[0206] The wrapped V-belt of the present invention has excellent durability. The endurance life of the wrapped V-belt may be, for example, 200 hours or more (e.g., 230 to 330 hours), preferably 240 hours or more (e.g., 250 to 325 hours), more preferably 260 hours or more (e.g., 270 to 320 hours), and particularly preferably 280 hours or more (e.g., 290 to 315 hours).

[0207] In the present application, the durability of the wrapped coupled V-belt can be measured by the method described in the examples.

[0208] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. The raw materials and preparation methods of the rubber composition, cord, outer cover fabric precursor, and link reinforcing layer precursor used, the belt preparation method, and measurement and evaluation methods will be described below.

[0209] [Rubber composition] (Materials used) EPDM1: "Nordel IP4520" manufactured by The Dow Chemical Company, Mooney viscosity [ML (1+4) 125°C] about 20, ethylene content 50% by mass, diene content (ethylidene norbornene content) 4.9% by mass EPDM2: "EPT4045M" manufactured by Mitsui Chemicals, Inc., Mooney viscosity [ML (1+4) 100°C] about 45, ethylene content 45% by mass, diene content (ethylidene norbornene content) 7.6% by mass Cotton staple fiber: "Cotton cut yarn" manufactured by Hashimoto Co., Ltd., average fiber length 6 mm Polyester staple fiber: "PET cut yarn" manufactured by Kou Staple Fibers, average fiber length 3 mm Carbon black SRF: "Seast S" manufactured by Tokai Carbon Co., Ltd., DBP absorption 68 mL / 100 g, BET specific surface area 27 m ２ / g, iodine adsorption capacity 26 g / kg Carbon black ISAF: "SEAST 6" manufactured by Tokai Carbon Co., Ltd., DBP absorption capacity 114 mL / 100 g, BET specific surface area 119 m ２ / g, iodine adsorption capacity 121 g / kg Carbon black HAF: "SEAST 3" manufactured by Tokai Carbon Co., Ltd., DBP absorption capacity 101 mL / 100 g, BET specific surface area 79 m ２ / g, iodine adsorption capacity 80 g / kg Clay: "Catalpo" manufactured by Sanyo Clay Industries Co., Ltd. Silica: "Ultrasil VN3" manufactured by Evonik Industries AG, BET specific surface area 180 m ２ / g Paraffinic oil: "Diana Process Oil PW90" manufactured by Idemitsu Kosan Co., Ltd. Antioxidant MBI (2-mercaptobenzimidazole): "Nocrac MB-O" manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Antioxidant ODPA (octylated diphenylamine): "Nocrac AD-F" manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Antioxidant DCD (4,4'-bis(α,α-dimethylbenzyl)diphenylamine): "Nocrac CD" manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Zinc oxide: "Zinc oxide type 2" manufactured by Sakai Chemical Industry Co., Ltd. Stearic acid: "Camellia stearate" manufactured by NOF Corporation Crosslinking accelerator TMTD (tetramethylthiuram disulfide): "Noccela TT" manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Crosslinking accelerator CBS (N-cyclohexyl-2-benzothiazolylsulfenamide): "Noccela CZ" manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Crosslinking accelerator MBTS (2,2'-dibenzothiazolyl disulfide): "Noccela DM" manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Co-crosslinking agent MPBM (N,N'-m-phenylenedimaleimide): "Balnoc PM" manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Adhesion improver A (resorcinol-formaldehyde co-condensate): "Penacolite Resin (B-18-S)" manufactured by INDSPEC Chemical Corporation Adhesion improver B (hexamethoxymethylmelamine): "POWERPLAST PP-1890S" manufactured by SINGH PLASTICISER & RESINS Organic peroxide: 1,3-bis(t-butylperoxyisopropyl)benzene Sulfur (powdered sulfur): Bigen Chemical

[0210] (Preparation of uncrosslinked rolled rubber sheets and bulk uncrosslinked rubber compositions for friction) Rubber compositions R1 to R2 having the formulations shown in Table 1 were kneaded in a Banbury mixer, and the kneaded rubber was passed through a calendar roll to prepare uncrosslinked (unvulcanized) rolled rubber sheets of predetermined thicknesses, which were used as sheets for compression rubber layers, adhesive rubber layers, tension rubber layers and / or protective layer rubber sheets.

[0211] Further, rubber composition R1 shown in Table 1 was kneaded in a Banbury mixer to prepare a bulk uncrosslinked (unvulcanized) rubber composition for friction to form an outer covering fabric precursor.

[0212] Furthermore, rubber composition R3 having the formulation shown in Table 1 was kneaded in a Banbury mixer, and this kneaded rubber was passed through a calendar roll to prepare an uncrosslinked (unvulcanized) rolled rubber sheet of a predetermined thickness, which was used as a rubber sheet for a connecting reinforcing layer to form a tie-band precursor.

[0213]

[0214] [Core Wire (Treated Cord)] Three aramid fiber bundles of 1670 dtex (1000 filaments) were aligned and twisted in the S direction with a twist coefficient of 3.0 to prepare a first twisted yarn, and five of the first twisted yarns were aligned and twisted in the Z direction with a twist coefficient of 3.0 to prepare a twisted cord (plied yarn) with a total fineness of 25050 dtex (15000 filaments) and a diameter of 1.9 mm, which was then subjected to an adhesive treatment. The twist coefficient TF is a value calculated by the following formula.

[0215] TF=TN×D0.5 / 960

[0216] [In the formula, TF is the twist factor, TN is the number of twists per meter, and D is the yarn fineness (tex)]

[0217] [Outer covering fabric precursor (treated canvas)] The outer covering fabric precursor was canvas (treated canvas) that had been subjected to adhesive treatment and friction treatment. 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 canvas was plain woven with a warp density of 75 / 50 mm and a weft density of 75 / 50 mm, for a basis weight of 280 g / m. ２ The canvas was immersed in an RFL liquid (a mixture of 2.6 parts by mass of resorcinol, 1.4 parts by mass of 37% formalin, 17.2 parts by mass of vinylpyridine-styrene-butadiene copolymer latex (manufactured by Nippon Zeon Co., Ltd.), and 78.8 parts by mass of water), dried, and then subjected to a wide-angle treatment so that the angle between the warp and weft yarns was 120 degrees. A treated canvas (basis weight approximately 500 g / m) was obtained by rubbing (friction) rubber composition R1 on both the front and back sides of the obtained wide-angle canvas. ２ , thickness about 0.6 mm) was used.

[0218] [Connected Reinforcement Layer Precursor (Treated Blind)] The blind was subjected to adhesive treatment and rubber sheet lamination treatment to obtain a connected reinforcement layer precursor. In detail, a blind-like fabric woven with a warp density of 120 / 50 mm and a weft density of 5 / 50 mm using a 470 dtex nylon 66 single-twisted cord (wire diameter 0.22 mm) as the warp and a 40 count cotton yarn (wire diameter 0.1 mm) as the weft was immersed in RFL liquid (a mixture of 2.6 parts by mass of resorcinol, 1.4 parts by mass of 37% formalin, 17.2 parts by mass of vinylpyridine-styrene-butadiene copolymer latex (manufactured by Nippon Zeon Co., Ltd.), and 78.8 parts by mass of water), and then dried. A treated blind (thickness about 0.7 mm) was used, in which a rubber sheet for a tie band of rubber composition R3 was laminated on both the front and back sides.

[0219] [Comparative Example 1 and Examples 1 to 6] (Preparation of Uncrosslinked Rubber Belt 1 (Tension Rubber Layer is R1)) A core wire was spirally wound around the outer periphery of a sheet (thickness 5.4 mm) for the compression rubber layer of R1 which had been wound around the outer periphery of a cylindrical drum, and a sheet (thickness 1.6 mm) for the tension rubber layer of R1 was further laminated on the outer periphery of this to form a cylindrical uncrosslinked sleeve in which the uncrosslinked rubber layer and the core wire were laminated. In other words, the rubber composition R1 was exposed on the outermost periphery of the uncrosslinked sleeve. The obtained uncrosslinked sleeve was cut in the circumferential direction while placed on the outer periphery of the cylindrical drum to form a ring-shaped uncrosslinked rubber belt 1.

[0220] (Skiving Process and Outer Fabric Covering Process (Coating Process)) The uncrosslinked rubber belt 1 was removed from the drum, and both side surfaces of the uncrosslinked rubber belt were skived at a predetermined angle to form a V-shaped cross section of the uncrosslinked rubber belt (skiving process). The uncrosslinked rubber belt with a V-shaped cross section (belt main body precursor: uncrosslinked V-belt including a tension rubber layer, a core (core wire), and a compression rubber layer) was subjected to a cover wrapping process in which the periphery was covered with an outer fabric precursor to form an uncrosslinked wrapped V-belt portion 1 (coating process).

[0221] In the covering step, outer covering fabric precursors of different widths were used, and the width direction of the outer covering fabric precursor was wound around the inner circumferential surface of the uncrosslinked rubber belt in the circumferential direction in a cross section perpendicular to the belt length direction (i.e., the length direction of the outer covering fabric precursor was directed toward the belt length direction), thereby changing the proportion of the uncovered region on the outer circumferential surface (back surface) of the wrapped V-belt portion after the connecting step (after crosslinking) to the proportion shown in Table 2 below. That is, in Examples 1 to 6, the shape shown in Fig. 4 was formed, and in Comparative Example 1, in Fig. 2, the outer covering fabric covering the inner circumferential surface was a single layer, and both ends of the outer covering fabric were formed facing each other on the outer circumferential surface side.

[0222] The outer covering fabric precursor was oriented so that the directions of the warp and weft yarns were inclined at 60° with respect to the belt length direction.

[0223] (Preparation of Joined V-Belt (Connecting Step)) The six obtained uncrosslinked wrapped V-belt portions 1 were fitted into annular grooves formed in a lower crosslinking mold, and then the treated damper (connecting reinforcement layer precursor) and the R1 protective layer rubber sheet (thickness 1.3 mm) were set as tie band precursors on the radially outer portions. That is, in setting the tie band precursor, the treated damper and the protective layer rubber sheet were wrapped in this order around the six uncrosslinked wrapped V-belt portions aligned in the width direction along the circumferential direction (belt length direction), and the tie band precursor was set on the six uncrosslinked wrapped V-belt portions. The treated damper 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.

[0224] The tie-band precursor and six uncrosslinked wrapped V-belt portions 1 thus set were sandwiched between an upper crosslinking mold and a lower crosslinking mold, pressurized to 1.2 MPa, and crosslinked at a crosslinking temperature of 160°C, thereby obtaining a crosslinked belt 1 in which six wrapped V-belt portions 1 (ASAB standard HB type, belt length 1600 mm) were connected and bonded with tie-bands.

[0225] The resulting crosslinked belt 1 was cut to produce a wrapped bonded V-belt 1 (cross-sectional dimensions: width 54.6 mm x thickness 12.7 mm) having three wrapped V-belt portions 1.

[0226] [Comparative Example 2, Examples 7 to 9, and Reference Example 1] (Preparation of Uncrosslinked Rubber Belt 2 (Tension Rubber Layer is R2)) A sheet for the second compressed rubber layer R1 (thickness 3.4 mm), a sheet for the first compressed rubber layer R2 (thickness 1.5 mm), and a sheet for the adhesive rubber layer R1 (thickness 0.5 mm) were laminated in this order on the outer circumferential surface of a cylindrical drum, and then a core wire was spirally wound thereon. Further, a sheet for the adhesive rubber layer R1 (thickness 0.5 mm) and a sheet for the tension rubber layer R2 (thickness 1.1 mm) were laminated in this order on the outer circumferential surface of the laminate to form a cylindrical uncrosslinked sleeve in which the uncrosslinked rubber layer and the core wire were laminated. In other words, the rubber composition R2 was exposed on the outermost circumferential surface of the uncrosslinked sleeve. The obtained uncrosslinked sleeve was cut circumferentially while placed on the outer periphery of the cylindrical drum to form a ring-shaped uncrosslinked rubber belt 2. Note that in the rubber layer R2 containing short fibers, the longitudinal direction of the short fibers was arranged approximately parallel to the belt width direction.

[0227] (Skiving Step and Outer Cover Fabric Covering Step (Coating Step)) An uncrosslinked wrapped V-belt portion 2 was formed in the same manner as the skiving step and covering step of [Comparative Example 1 and Examples 1 to 6], except that an uncrosslinked rubber belt 2 was used instead of the uncrosslinked rubber belt 1, and that in the covering step, the proportion of the uncovered region on the outer peripheral surface (back surface) of the wrapped V-belt portion was changed to the proportion shown in Table 3 described below. That is, Examples 7 to 9 were formed into the shape shown in Fig. 4, Reference Example 1 was formed into the shape shown in Fig. 3 in which the outer cover fabric covering the inner peripheral surface was a single layer, and Comparative Example 2 was formed into the shape shown in Fig. 2 in which the outer cover fabric covering the inner peripheral surface was a single layer and both ends of the outer cover fabric faced each other on the outer peripheral surface side.

[0228] (Preparation of joined V-belt (connecting step)) A crosslinked belt 2 was obtained in which six wrapped V-belt portions 2 (ASAB standard HB type, belt length 1600 mm) were connected and bonded with tie bands in the same manner as in [Comparative Example 1 and Examples 1 to 6], except that the R2 protective layer rubber sheet (thickness 1.3 mm) was used instead of the R1 protective layer rubber sheet (thickness 1.3 mm) and that the longitudinal direction of the short fibers in the R2 protective layer rubber sheet was arranged so as to be approximately parallel to the belt width direction.

[0229] The resulting crosslinked belt 2 was cut to produce a wrapped bonded V-belt 2 (cross-sectional dimensions: width 54.6 mm x thickness 12.7 mm) having three wrapped V-belt portions 2.

[0230] Examples 10 to 12 Wrapped bonded V-belts having the cross-sectional shape shown in FIG. 6 were manufactured by changing the number of outer cover fabric layers in Examples 4 to 6 (tension rubber layer: R1, proportion of uncovered region: 50%, 70%, or 90%, number of outer cover fabric layers: 1) to two. That is, wrapped bonded V-belts having three wrapped V-belt portions 1 were manufactured in the same manner as Examples 4 to 6, except that in the covering step, the uncrosslinked rubber belt 1 was wrapped with the outer cover fabric precursor twice, and the thicknesses of the compression rubber layer sheets and tension rubber layer sheets were adjusted to be thinner as the number of outer cover fabric layers increased to match the cross-sectional dimensions of Examples 4 to 6. In the covering step, to achieve the cross-sectional shape shown in FIG. 6, the outer cover fabric (first outer cover fabric) was wrapped along the inner cover fabric (second outer cover fabric) (so that both the first and second outer cover fabrics covered the same region of the outer peripheral surface of the belt main body).

[0231] Examples 13 and 14 Wrapped bonded V-belts were manufactured by changing the number of outer fabric layers from Example 11 (tension rubber layer: R1, proportion of uncovered region: 70%, number of outer fabric layers: 2) to three (Example 13) or four (Example 14). That is, wrapped bonded V-belts having three wrapped V-belt portions 1 were manufactured in the same manner as Example 11, except that in the covering step, the uncrosslinked rubber belt 1 was wrapped with the outer fabric precursor three or four times, and the thicknesses of the compression rubber layer sheets and the tension rubber layer sheets were adjusted to be thinner as the number of outer fabric layers increased to make the cross-sectional dimensions uniform. In the covering step, the covering step was performed so that each outer fabric was aligned with the adjacent outer fabric (so that all outer fabrics covered the same region of the outer surface of the belt main body) to achieve a cross-sectional shape conforming to FIG. 6.

[0232] Examples 15 and 16 Wrapped bonded V-belts having the cross-sectional shape shown in Fig. 7 were produced in the same manner as in Examples 11 and 12 (tension rubber layer: R1, uncoated region ratio: 70% or 90%, number of outer layer layers: 2), except that the uncoated region ratio of the inner outer layer (second outer layer) was changed to 100%. That is, in the covering step, the outer peripheral surface of the uncrosslinked rubber belt 1 was not covered in the first cover wrapping treatment, and only the inner peripheral surface and both side surfaces were covered with the outer layer precursor, and in the second cover wrapping treatment, both sides of the outer peripheral surface were covered so that the uncoated region ratio of the outer outer layer (first outer layer) was 70% (Example 15) or 90% (Example 16).

[0233] Reference Example 2 A wrapped joined V-belt having three wrapped V-belt portions 1 was manufactured in the same manner as in Examples 15 and 16, except that the proportion of the uncovered area of ​​not only the inner outer covering fabric (second outer covering fabric) but also the outer outer covering fabric (first outer covering fabric) was changed to 100% (even in the second cover wrapping process, the outer peripheral surface of the uncrosslinked rubber belt 1 was not covered, and only the inner peripheral surface and both side surfaces were covered with the outer covering fabric precursor).

[0234] [Rubber exposure on the side of the wrapped V-belt] After the joining process (after crosslinking), the wrapped V-belt was checked for the presence or absence of an area where the rubber was exposed without being covered with the outer fabric on the side of the wrapped V-belt. The results are shown in the table below.

[0235] [Peel Test] The resulting wrapped bonded V-belt was separated along the three wrapped V-belt portions (divided into three pieces), and the peel force of the tie band was measured. Specifically, a 15 cm section was cut from the separated endless belt in the belt length direction to prepare a peel test sample. A notch was made with a blade on the cut surface between the tie band and the wrapped V-belt portion, and the tie band and the wrapped V-belt portion were pulled apart (at a peel angle of 180°, i.e., so that the tie band was folded back 180° relative to the wrapped V-belt portion) using an autograph (Shimadzu Corporation, "AGS-J10kN") to measure the peel force when peeled along the belt length. The peel force was determined by dividing the measured tensile force by the width of the peel surface [the width of the outer peripheral surface of the wrapped V-belt portion (the combined width of the covered and uncovered regions)] to obtain a value per 1 cm of width.

[0236] The peel test samples were cut out from any three positions of the cut endless belt, and the arithmetic average of the values ​​(peel force) obtained from the three samples was used. When exposed rubber was found on the side of the wrapped V-belt portion, the peel test samples were cut out from any three positions in the part (or section) where the rubber was not exposed on the side.

[0237] Although it depends on the conditions of use, it is believed that peeling is likely to occur when the peeling force of the tie band is less than about 50 N / cm. The results are shown in the table below and in Figure 8.

[0238] [Proportion of Uncoated Region] A 3 cm sample was cut from the center of the wrapped V-belt portion after the peel test (the wrapped V-belt portion obtained by peeling the tie band from the peel test sample) in the belt length direction as an observation sample, and the peeled surface (outer peripheral surface) was observed. Specifically, the peeled surface was photographed with a microscope ("VHX-5000" manufactured by Keyence Corporation), and analyzed with measurement software ("Stream" manufactured by Olympus Corporation) so that the uncoated region and the coated region were recognized as different regions in the photographed image, and the proportion of the uncoated region was calculated from the area ratio of each region.

[0239] The percentage of the uncoated area was calculated for each of the observation samples obtained from the three peel test samples, and the arithmetic mean value of the values ​​(percentage of the uncoated area) obtained from the three samples was used. The results are shown in the table below.

[0240] [Ride-out Change] A wrapped bonded V-belt was placed around a pair of pulleys with a diameter of 113 mm in an atmosphere of 80°C, and an axial load of 500 N was applied. The position of the back surface of the belt at this time was measured with a laser displacement meter and set as the origin (0 mm). Next, the axial load was increased to 2000 N, and the change in the position of the back surface of the belt (ride-out change) was measured. It can be determined that the smaller the ride-out change, the better the side pressure resistance. The results are shown in the table below.

[0241] [Wear Rate] As shown in Figure 9, wear resistance was evaluated using a biaxial running tester consisting of a drive (Dr.) pulley with a diameter of 180 mm and a driven (Dn.) pulley with a diameter of 180 mm. Specifically, a wrapped bonded V-belt was hung on each pulley, and the belt was run for 96 hours at an ambient temperature of 23°C under an axial load of 1600 N, a drive pulley rotation speed of 1800 rpm, and a load of 53 N m on the driven pulley. The mass of the belt was measured before and after running, and the mass change rate (wear rate) was evaluated using the following formula. The smaller the wear rate, the better the wear resistance. The results are shown in the table below.

[0242] Wear rate (%) = [(W ０ -W １ ) / W ０ ]×100

[0243] [In the formula, W ０ indicates the mass of the belt before running (g), and W １ indicates the mass (g) of the belt after running.]

[0244] [Durability Life] As shown in Figure 10, the durability life of the wrapped V-belt was evaluated using a triaxial running tester equipped with a 100 mm diameter drive (Dr.) pulley, a 100 mm diameter driven (Dn.) pulley, and an 85 mm diameter back tension (Ten.) pulley. Specifically, the wrapped V-belt was suspended on each pulley, the contact angle of the belt with respect to the back tension pulley was adjusted to 20 degrees, and a load of 588 N was applied to the driven pulley. The drive pulley was rotated at 3600 rpm, the driven pulley was unloaded, and the belt was run at an ambient temperature of 110°C until its end of life. The running time (unit: h (hours)) was defined as the durability life. The belt's end of life was defined as the point at which the tie bands peeled off in a continuous section of 100 mm or more in the belt length direction. The results are shown in the table below.

[0245]

[0246]

[0247] As is clear from Tables 2 and 3 and Fig. 8, in all of Examples 1 to 6 (the tension rubber layer was R1) and Examples 7 to 9 and Reference Example 1 (the tension rubber layer was R2), the peel force increased as the area ratio of the uncovered region not covered by the outer covering fabric to the entire area of ​​the back surface of the wrapped V-belt increased. However, when the area ratio of the uncovered region exceeded 80%, areas that were not covered by the outer covering fabric occurred on the side surfaces of the wrapped V-belt. Comparing the cases where the tension rubber layer was R1 and R2, the peel force was slightly higher for R1.

[0248]

[0249] As is clear from Table 4, all Examples showed high peeling force. Furthermore, not only was there no exposure of rubber on the side surface of the wrapped V-belt portion of the belt immediately after manufacture, but also after running (after evaluation of the wear rate and durability life), peeling of the outer covering fabric at the boundary between the side surface of the wrapped V-belt portion and the tie band was suppressed, and the wear rate was kept low and the durability life was also excellent in all Examples.

[0250] In Examples 10 to 12, the outer covering fabric of Examples 4 to 6 was changed to two layers, and as in Examples 4 to 6, the peel force increased as the area ratio of the uncovered region increased. Meanwhile, in Example 6 (90%), which had a large area ratio of uncovered region, there were a few areas on the side of the wrapped V-belt that were not covered by the outer covering fabric (areas where rubber was exposed). In contrast, in Example 12, which had two layers of outer covering fabric, even if rubber was exposed on the side in the first cover wrapping process, the exposed areas could be covered by the second cover wrapping process. Therefore, despite the large area ratio of uncovered region, the wrapped V-belt was manufactured without rubber being exposed on the side. Furthermore, the rideout change and wear rate were similar in Examples 10 to 12, but the durable life was particularly high in Examples 11 and 12, which had a large area ratio of uncovered region.

[0251] Examples 13 and 14 are examples in which the outer covering fabric of Example 5 was changed to three or four layers. Comparing Examples 5, 11, 13, and 14, which differ in the number of layers of the outer covering fabric, showed similar wear rates. However, the increase in the number of layers tended to increase the amount of rideout change (the belt was more likely to drop onto the pulley when tension was applied, and lateral pressure resistance tended to decrease). Examples 13 and 14 (especially Example 14), which had three or four layers of the outer covering fabric, showed a significant decrease in lateral pressure resistance. While the reason for this is unclear, it is presumed to be due to a relative decrease in the proportion of the belt body (hard rubber portion), which is harder than the outer covering fabric, as the number of layers of the outer covering fabric increased. In Examples 13 and 14, which showed such decreased lateral pressure resistance, the durability life tended to be slightly reduced, possibly because a force was more likely to act in the direction of separation from the tie band when the wrapped V-belt portion dropped toward the center of the pulley during operation.

[0252] On the other hand, Example 5, which had a single outer fabric layer, had the smallest ride-out change and excellent side pressure resistance, and although the peel force and wear rate were similar to those of Example 11, Example 11, which had two outer fabric layers, had a superior durability life. The reason for this is unclear, but it is thought that Example 5, which had only a single outer fabric layer, was prone to exposing or seeping out the rubber of the belt body from worn areas of the outer fabric, even though the wear rate was similar. In other words, it is presumed that the exposure or seeping out of the rubber that occurred during belt operation increased the coefficient of friction between the belt and the pulley, and the resulting large heat generation reduced the adhesive strength at the joint with the tie band, making it more likely to peel off from the tie band.

[0253] Therefore, Example 11, which has two layers of outer covering fabric, effectively suppresses the exposure or seepage of rubber while also having excellent resistance to lateral pressure, and as a result, it had the longest durability among Examples 5, 11, 13, and 14.

[0254]

[0255] Examples 15 and 16 are examples in which the proportion of the uncovered area of ​​the inner outer cover fabric (second outer cover fabric) of the two-layer outer cover fabric in Examples 11 and 12 was changed to 100%. That is, in Examples 11 and 12, the outer outer cover fabric (first outer cover fabric) and the inner outer cover fabric overlap each other to cover the belt body (as shown in FIG. 6 ), whereas in Examples 15 and 16, the inner outer cover fabric does not cover the back surface of the belt, and only the outer outer cover fabric forms the covered area, as shown in FIG. 7 . Similar to Examples 11 and 12, Examples 15 and 16 exhibited high peel strength. Furthermore, in Examples 15 and 16, not only was there no exposure of rubber on the side surfaces of the wrapped V-belt portion of the belt immediately after manufacture, but also, after running (after evaluation of wear rate and durability), the wear rate was kept low and durability life was excellent, likely due to the suppression of peeling of the outer cover fabric at the boundary between the side surfaces of the wrapped V-belt portion and the tie bands.

[0256] In Examples 15 and 16, the peel force increased as the area ratio of the uncovered region formed only by the outer covering fabric (first covering fabric) increased, similar to Examples 11 and 12. Furthermore, in Example 16, even with a large area ratio of the uncovered region, the wrapped V-belt could be manufactured without exposing the rubber from the side surface, similar to Example 12. The rideout change and wear rate were comparable in Examples 15 and 16, but the durability life was longer in Example 16, which had a larger area ratio of the uncovered region.

[0257] In Reference Example 2, the proportion of the uncovered area of ​​not only the inner outer covering fabric (second outer covering fabric) but also the outer outer covering fabric (first outer covering fabric) was changed to 100%, i.e., a manufacturing example was performed so that neither the inner nor outer covering fabric formed a covered area. Although Reference Example 2 exhibited high peel strength, the rubber was exposed on the side surface of the wrapped V-belt portion of the belt immediately after manufacturing, and the outer covering fabric was prone to peeling at the boundary between the side surface of the wrapped V-belt portion and the tie band during running (during evaluation of wear rate and durability life), resulting in a high wear rate and a short durability life.

[0258] Among the Examples, Examples 11 to 12 and 15 to 16 were excellent in terms of the balance of adhesion to the tie band, abrasion resistance, lateral pressure resistance, durability, productivity, etc., and Examples 11 and 15, which had an uncoated region of 70%, were particularly excellent in that they satisfied these requirements in a well-balanced manner at a high level while also being even more productive (better workability in the coating process and improved yield).

[0259] 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. It may also be used in high-load machinery used in high-load, long-span layouts, such as large agricultural machinery used in Europe and the United States, specifically cultivators, vegetable transplanters, transplanters, binders, combine harvesters, vegetable harvesters, threshers, bean cutters, corn harvesters, potato harvesters, and beet harvesters.

[0260] Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit and scope of the present invention. This application is based on Japanese Patent Application No. 2023-195203 filed on November 16, 2023, and Japanese Patent Application No. 2024-193031 filed on November 1, 2024, the contents of which are incorporated herein by reference.

[0261] DESCRIPTION OF SYMBOLS 1, 11, 21, 31... Wrapped combined V-belt V... Wrapped V-belt portion 2, 12, 22, 32... Compression rubber layer 3, 13, 23, 33... Core layer (core, adhesive rubber layer) 4, 14, 24, 34... Tension rubber layer 4a, 14a, 24a, 34a... Uncovered region 5, 15, 25, 35... Outer cover fabric (first outer cover fabric or outer outer cover fabric) 26, 36... Outer cover fabric (second outer cover fabric or inner outer cover fabric) 5a, 15a, 25a, 26a, 35a... Covered region T... Tie band

Claims

1. A wrapped connected V-belt including a plurality of wrapped V-belt sections whose belt main body is covered with an outer covering fabric, and tie bands connecting the plurality of wrapped V-belt sections at the outer circumferential surfaces of the wrapped V-belt sections, wherein the outer circumferential surface of the wrapped V-belt sections has a covered area covered with the outer covering fabric and an uncovered area that is not covered, the covered area is formed on at least one side of the outer circumferential surface, and the outer covering fabric that covers this covered area also covers the side surface of the wrapped V-belt sections.

2. The wrapped, bonded V-belt of claim 1, wherein said covered and uncovered regions extend along the length of the belt.

3. The wrapped, connected V-belt according to claim 1 or 2, wherein the covering region is formed on both sides of the outer circumferential surface.

4. The wrapped combined V-belt according to any one of claims 1 to 3, wherein the area ratio of the uncovered region to the area of ​​the outer circumferential surface of the wrapped V-belt portion is 25 to 95%.

5. The wrapped, bonded V-belt according to any one of claims 1 to 4, wherein the belt body is covered with one to three layers of outer covering fabric.

6. The wrapped, bonded V-belt according to any one of claims 1 to 5, wherein the belt body is covered with a plurality of layers of outer covering fabric.

7. The wrapped combined V-belt according to any one of claims 1 to 6, wherein the belt body is covered with a plurality of layers of outer cover fabric, a first outer cover fabric located outermost among the plurality of layers of outer cover fabric forms the covered region on the outer circumferential surface, and one or more second outer cover fabrics located inside the first outer cover fabric do not cover the outer circumferential surface.

8. The wrapped bonded V-belt according to any one of claims 1 to 7, wherein the tie band comprises at least a fiber.

9. A method for producing a wrapped coupled V-belt comprising at least a covering step of covering a belt body precursor with an outer covering fabric precursor to form a wrapped V-belt precursor, and a connecting step of connecting the outer peripheral surfaces of a plurality of wrapped V-belt precursors obtained in the covering step with tie band precursors, wherein in the covering step, the inner peripheral surface and both side surfaces of the belt body precursor are covered, at least one side of the outer peripheral surface is covered with the outer covering fabric precursor that covers the side surfaces, and a partial area of ​​the outer peripheral surface is not covered. The method for producing a wrapped coupled V-belt according to any one of claims 1 to 8.

10. The manufacturing method according to claim 9, which does not include a removing step of cutting off or removing the outer covering fabric precursor covering the outer peripheral surface side of the wrapped V-belt portion precursor obtained in the covering step.

11. A manufacturing method as described in claim 9 or 10, wherein in the covering step, the width of the outer cover fabric precursor is shorter than the perimeter of the cross-sectional shape perpendicular to the longitudinal direction of the belt body precursor, and the width direction of the outer cover fabric precursor is directed in a direction perpendicular to the belt longitudinal direction.

12. A manufacturing method according to any one of claims 9 to 11, wherein in the covering step, the inner peripheral surface, both side surfaces, and at least one side of the outer peripheral surface of the belt body precursor are at least covered with a seamless outer cover fabric precursor.

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