Wrapped bonded V-belt and its manufacturing method

Abstract

Provided is a wrapped combined V-belt that can improve the adhesive strength between a wrapped V-belt portion and a tie band and can suppress peeling of an outer cover fabric at the boundary between the side surface of the wrapped V-belt portion and the tie band. [Solution] A wrapped joined V-belt 1 is manufactured, which includes a plurality of wrapped V-belt portions V whose belt main body portion is covered with an outer cover cloth 5, and a tie band T connecting the outer peripheral surfaces of the plurality of wrapped V-belt portions V, the outer peripheral surface of the wrapped V-belt portion V having a covered region 5a covered with the outer cover cloth 5 and an uncovered region 4a that is not covered, the covered region 5a being formed on at least one side of the outer peripheral surface, and the outer cover cloth 5 covering this covered region 5a also covering the side surface of the wrapped V-belt portion V.

Description

[Technical field]

[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. [Background technology]

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

[0003] For agricultural machinery and other applications, wrapped V-belts are used, in which the entire belt surface, including the friction transmission surface, is covered with an outer sheath (cover cloth). The reason for this is that if a raw edge V-belt is used, which is a rubber layer with an exposed friction transmission surface, the friction coefficient of the transmission surface is high, which increases the stress on the belt and leads to premature breakage, and if the belt becomes entangled with straw, stones, wood, etc., the sudden impact on the transmission surface may damage the belt or the entire transmission mechanism. By using a wrapped V-belt, the friction coefficient of the transmission surface is reduced, allowing for moderate slippage and reducing the stress and impact on the belt. In addition, the transmission surface is protected, making it less likely to be damaged.

[0004] Large agricultural machinery used on large farms in Europe and the US needs to transmit huge amounts of power, and so it becomes necessary to use multiple V-belts at the same time. In other words, it is necessary to wrap multiple V-belts in parallel around the pulleys of the belt transmission mechanism (multiple threads) and rotate them. When multiple V-belts are used, tension differences occur between the multiple parallel V-belts, which may impair stable power transmission. Furthermore, there is a risk that contact between adjacent V-belts may cause the inner and outer periphery of the belt to be reversed, 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). As the V-belt portion, a wrapped V-belt (wrapped V-belt portion) covered with an outer sheath (covering fabric) may be used. 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 partial cross-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 therebetween, and the two wrapped V-belts 101 are connected at their outer circumferential surfaces by a connecting member (tie band) 102 made of fabric. Each wrapped V-belt 101 is formed of an endless belt body (belt body portion) formed of an tension rubber layer 104 on the outer circumferential side of the belt, a compression rubber layer 103 on the inner circumferential side of the belt, and a core body 105 embedded between the tension rubber layer 104 and the compression rubber layer 103 along the belt longitudinal direction (circumferential direction, A direction in the figure), and an outer cover fabric 106 (woven fabric, knitted fabric, nonwoven fabric, etc.) that covers the periphery of this belt 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, there is a wrapped coupled V-belt 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 as disclosed in Patent Document 1 is shown in FIG.

[0008] In the conventional wrapped connected V-belt 111 shown in Fig. 2, a plurality of wrapped V-belt parts V (two in the figure) arranged in parallel at intervals in the belt width direction (direction B in Fig. 1) are connected by tie bands (connecting members) T, and each wrapped V-belt part V is composed of an endless belt main body part that has a cross-sectional inverted trapezoidal shape and extends in the belt length direction (circumferential direction, direction A in Fig. 1), in which a compression rubber layer 112, a core body 113, and an tensile rubber layer 114 are laminated in this order from the inner periphery side of the belt to the outer periphery side, and an outer cover cloth (cover cloth) 115 that covers the periphery of this belt main body part. This outer cover cloth 115 is formed of a seamless (single continuous piece of) fabric, and covers the entire surface of the belt main body part (inner periphery surface, both side surfaces, and outer periphery surface of the belt), and the outer cover cloth 115 is overlapped on the inner periphery side to form a two-layer structure.

[0009] However, such a conventional wrapped connected 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 connected or joined 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 connect or join with 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) side of the wrapped V-belt portion. For example, JP 2020-37257 A (Patent Document 2) describes that the outer peripheral side portion of the unvulcanized rubber belt covered with an outer covering cloth is cut in the circumferential direction to expose the rubber layer, and in the vulcanization process, a reinforcing cloth (tie band) is placed on the outer peripheral side in a state where a plurality of unvulcanized rubber belts with exposed rubber layers are arranged in parallel and vulcanized, so that the rubber layer exposed from the unvulcanized rubber belt and the reinforcing cloth (tie band) are bonded by vulcanization, thereby improving the adhesive strength compared to the conventional one in which the outer covering cloth and the reinforcing cloth (tie band) are bonded. In addition, JP 2022-102656 A (Patent Document 3) describes a configuration in which the upper part of a semi-vulcanized annular laminate structure (precursor of the belt main body) is buffed with a grindstone or sandpaper to remove the reinforcing cloth (outer covering cloth) 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 annular laminate structures in the semi-vulcanized state with the tie bands attached are completely vulcanized. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Special Publication No. 47-34432 [Patent Document 2] JP 2020-37257 A [Patent Document 3] JP 2022-102656 A Summary of the Invention [Problem to be solved by the invention]

[0012] Fig. 3 shows a schematic partial cross-sectional view of the wrapped combined V-belt disclosed in Patent Documents 2 and 3. The wrapped combined V-belt 121 shown in Fig. 3 is different from the wrapped combined 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 is cut or removed. That is, the wrapped combined V-belt 121 is composed of a belt main body portion in which a compressed rubber layer 122, a core body 123, and an tensile rubber layer 124 are laminated in this order from the inner peripheral side to the outer peripheral side of the belt, and a two-stage outer cover cloth 125 that covers the inner peripheral surface and both side surfaces of the belt main body portion, in which a plurality of wrapped V-belt portions V (two in the figure) are arranged in parallel with an interval in the belt width direction. The two stages of outer cover cloth 125 are overlapped on the inner circumferential side, but before being connected to the tie band T, they were formed of a seamless (single continuous piece of fabric) like the outer cover cloth 115 of the wrapped combined 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. The cutting away of the outer circumferential side exposes the tensile rubber layer 124, and the outer circumferential side surface 124a of this exposed tensile rubber layer 124 is in direct contact with the tie band T, so that 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 process of exposing the rubber layer from the outer peripheral surface (back surface) side after covering the wrapped V-belt portion with the outer covering fabric, and Patent Document 3 also requires a process of semi-vulcanizing the material, which makes the process complicated and causes material loss, resulting in cost disadvantages. Also, 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 FIG. 3) on the side surface of the wrapped V-belt portion.

[0014] Therefore, an object of the present invention is to provide a wrapped combined 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 manufacturing method thereof.

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

[0016] Still another object of the present invention is to provide a wrapped combined 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 manufacturing method thereof.

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

[0018] As a result of intensive research by the inventors to achieve the above object, it was found that by forming a covered region covered with an outer covering fabric and an uncovered region on the outer peripheral surface of the wrapped V-belt portion, and by covering the side portion of the outer peripheral surface with the outer covering fabric that covers the side surface of the wrapped V-belt portion to form a covered region (by folding from the side surface toward the outer peripheral surface), not only can the adhesive strength with the tie band be effectively improved, but also peeling of the outer covering fabric at the boundary portion with the tie band can be suppressed, and the present invention has been completed. That is, the present invention may include the following aspects.

[0019] Aspect [1]: A wrapped connected V-belt including a plurality of wrapped V-belt portions in which a belt main body portion is covered with an outer covering fabric, and a tie band connecting the plurality of wrapped V-belt portions on the outer peripheral surface of each wrapped V-belt portion, The outer peripheral surface of the wrapped V-belt portion has a covered region covered with the outer covering fabric and an uncovered region that is not covered, A wrapped bonded V-belt, wherein the covered region is formed on at least one side of the outer circumferential surface, and an outer cover fabric covering the covered region also covers a side surface of the wrapped V-belt portion.

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

[0021] Aspect [3]: The wrapped, coupled 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 coupled V-belt according to any one of aspects [1] to [3], wherein the area ratio of the uncovered region to the area of ​​the outer peripheral surface of the wrapped V-belt portion is 25 to 95% (e.g., 25 to 85%).

[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 coupled 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 belt body is covered with multiple layers of outer covering fabric, Among the multiple layers of outer cover fabrics, a first outer cover fabric located on the outer periphery forms the covering region on the outer periphery (covers a part of the outer periphery), The wrapped coupled V-belt according to any one of aspects [1] to [6], wherein one or more second outer cover fabrics positioned on the inside of the first outer cover fabric 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 covering step of covering a belt body precursor with an outer cover fabric precursor to form a wrapped V-belt precursor; a connecting step of connecting outer circumferential surfaces of the plurality of wrapped V-belt portion precursors obtained in the covering step with a tie band precursor, The method for producing a wrapped coupled V-belt according to any one of aspects [1] to [8], 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 portion of the outer peripheral surface is covered with an outer covering fabric precursor that covers the side surfaces, and a part of the outer peripheral surface is not covered.

[0028] Aspect

[10] : The manufacturing method according to aspect [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.

[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 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 covered in a direction perpendicular to the belt longitudinal 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 at least covered with a seamless (single continuous) outer covering fabric precursor. Effect of the Invention

[0031] In the present invention, the outer peripheral surface of the wrapped V-belt portion is provided with a covered region covered by the outer covering fabric and an uncovered region not covered, 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 to the outer peripheral surface side). This effectively improves the adhesive strength between the wrapped V-belt portion and the tie band, and also effectively suppresses peeling of the outer covering fabric at the boundary between the side surface of the wrapped V-belt portion and the tie band. Furthermore, it is possible to achieve both the improvement of the adhesive strength and the improvement of productivity (or the reduction of the defective rate). In addition to these, it is also possible to satisfy the improvement of the abrasion resistance and the improvement of the lateral pressure resistance. Moreover, it is possible to provide a wrapped combined V-belt that can suppress peeling between the wrapped V-belt portion and the tie band and has excellent durability (durable life). [Brief description of the drawings]

[0032] [Figure 1] FIG. 1 is a schematic, partially sectional perspective view showing an example of a conventional wrapped connected V-belt. [Diagram 2] FIG. 2 is a schematic partial cross-sectional view showing another example of a conventional wrapped connected V-belt. [Diagram 3] FIG. 3 is a schematic partial cross-sectional view showing still another example of a conventional wrapped connected V-belt. [Figure 4] FIG. 4 is a schematic partial cross-sectional view showing an example of a wrapped bonded V-belt of the present invention. [Diagram 5] FIG. 5 is a schematic partial cross-sectional view showing another example of the wrapped connected V-belt of the present invention. [Figure 6] FIG. 6 is a schematic partial cross-sectional view showing still another example of the wrapped connected V-belt of the present invention. [Figure 7] FIG. 7 is a schematic partial cross-sectional view showing another example of the wrapped connected V-belt of the present invention. [Figure 8] FIG. 8 is a graph showing the relationship between the ratio of the uncovered area of ​​the wrapped combined V-belts obtained in the Examples, Reference Examples, and Comparative Examples and the peeling force of the tie band. [Figure 9]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 joined V-belts obtained in the Examples and Reference Examples. [Figure 10] FIG. 10 is a schematic diagram showing the layout of a three-axis running test machine used to evaluate the durability life of the wrapped joined V-belts obtained in the examples and reference examples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[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 connected 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 a tie band connecting the wrapped V-belt sections at their outer peripheral surfaces, and the outer peripheral surface of the wrapped V-belt sections has a covered region covered with the outer covering fabric and an uncovered region. A schematic partial cross-sectional view of an example of the wrapped connected V-belt of the present invention is shown in Figure 4.

[0035] The wrapped combined V-belt 1 shown in FIG. 4 differs from the conventional wrapped combined 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 combined V-belt 1 is composed of a belt main body portion 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 circumferential side of the belt to the outer circumferential side (back side) of a plurality of wrapped V-belt portions V (two in the figure) spaced apart in the belt width direction and arranged in parallel, 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 circumferential surface of the belt, both side surfaces, and a partial area of ​​the outer circumferential surface, thereby forming the covered area 5a and the uncovered area (exposed portion of the tension rubber layer 4) 4a on the outer circumferential surface side of the wrapped V-belt portion V.

[0037] The covered region 5a and the uncovered region (exposed portion of the tensile rubber layer 4) 4a are formed to extend in the length direction of the belt, and preferably are formed over the entire length or circumference of the belt in the length direction or circumferential direction, like the other elements (compressed rubber layer 2, core body 3, tensile 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 tensile 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 cross-linking during the formation of the tensile rubber layer 4.

[0039] The uncovered region (exposed portion of the tension rubber layer 4) 4a is formed in the center or inside of the belt outer peripheral surface (an inner region on the outer peripheral surface spaced from both ends in the belt width direction), and the covered region 5a is formed on both sides of the belt outer peripheral surface (regions on the outer peripheral surface near both ends in the belt width direction). In this example, the outer cover cloth 5 is formed of a seamless (continuous) fabric, so that the inner peripheral surface, both side surfaces, and a portion of the outer peripheral surface (covered regions 5a on both sides of the outer peripheral surface) are covered seamlessly (continuously). Therefore, the ends of the outer cover cloth 5 covering the inner peripheral 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, when the ends of the outer cover cloth 5 are folded (or buried) (i.e., when the outer cover cloth 5 covering the covered area 5a also covers the side surface of the wrapped V-belt portion V), the ends of the outer cover cloth 5 do not come into contact with pulleys, etc., and therefore, unlike the conventional wrapped combined V-belt 121 shown in Figure 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 (continuous) 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, so that productivity can be effectively improved.

[0041] In this example, the outer cover cloth 5 is a continuous piece of fabric that is continuous in the circumferential direction of the belt cross section (cross section perpendicular to the belt length direction). However, two or more pieces of fabric may be joined (connected) at their ends or may be joined by partially overlapping each other. For example, the outer cover cloth 5 in FIG. 4 may be formed by overlapping two pieces of fabric on the inner circumferential surface of the belt or on one side (for example, overlapping on the inner circumferential surface of the belt as in the outer cover cloth 125 of the conventional wrapped joint 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, and one of the covered regions, 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, and the other covered 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] Fig. 5 shows a schematic partial cross-sectional view of another example of the wrapped combined V-belt of the present invention. The wrapped combined V-belt 11 shown in Fig. 5 is different from the wrapped combined V-belt 1 shown in Fig. 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 part other than the covered region 15a formed only on one side of the outer circumferential surface is the uncovered region 14a). Therefore, the compressed rubber layer 12 and the core body 13 are the same as the compressed rubber layer 2 and the core body 3 of the wrapped combined V-belt 1, and the tensile rubber layer 14 and the outer covering cloth 15 are the same as the tensile rubber layer 4 and the outer covering cloth 5, except that their shapes are different corresponding to the uncovered region 14a and the covered region 15a. In such an embodiment, the area of ​​the uncovered region 14a is large, and the adhesive force can be improved more effectively.

[0043] In addition, when forming a covering region 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 combined V-belt [i.e., on the outer peripheral surface side on the outer side in the belt width direction in the wrapped V-belt part on the outermost side (both ends) in the belt width direction]. For example, in the case of a wrapped combined V-belt having two wrapped V-belt parts, 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. In this embodiment, peeling of the outer covering fabric can be effectively suppressed. That is, when the wrapped combined V-belt is 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 combined V-belt, both ends in the belt width direction tend to come into contact with the flange parts of these pulleys [regulating parts or regulating walls formed on both sides in the thickness direction (axial direction) of the pulley to prevent the belt from deviating] more frequently. Therefore, the outer covering fabric tends to peel off more easily on the outermost side in the belt width direction, but by forming the covering region on the outermost side (both ends) in the belt width direction, peeling of the outer covering fabric can be effectively suppressed.

[0044] Fig. 6 shows a schematic partial cross-sectional view of yet another example of the wrapped combined V-belt of the present invention. The wrapped combined V-belt 21 shown in Fig. 6 differs from the wrapped combined V-belt 1 shown in Fig. 4 in that the outer cover fabric is made of two layers, but other configurations (compressed rubber layer 22, core body 23, etc.) are similar to the wrapped combined V-belt 1. In the wrapped combined V-belt 21 in Fig. 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 on the inside (belt body side) of the first outer cover fabric. The second outer cover cloth 26 on the inside is formed of an unbroken (continuous) fabric, similar to the outer cover cloth 5 in the wrapped combined V-belt 1 in Fig. 4, and covers the inner circumferential surface, both side surfaces, and a part of the outer circumferential surface (covered areas on both sides of the outer circumferential surface) 26a of the belt without any breaks (continuous form), and the first outer cover cloth 25 formed of an unbroken (continuous) fabric along this second outer cover cloth 26 similarly covers the outside of the belt (outside the second outer cover cloth 26) to form covered areas 25a on both sides of the belt outer circumferential surface. In this manner, the outer cover cloth has multiple layers, so that even if the outer cover cloth wears on the side surfaces of the V-belt portion, the rubber of the belt main body can be effectively prevented from being exposed.

[0045] In this example, similarly to the wrapped bonded V-belt 1 in Fig. 4, the uncovered region 24a [the exposed portion (exposed surface) of the tensile rubber layer 24] can come into direct contact with the tie band T, and can be bonded or connected to the tie band T with high adhesive strength by cross-linking. In addition, the outer cover cloths 25, 26 covering the covered regions 25a, 26a also cover the belt side surfaces (i.e., the ends of the outer cover cloths 25, 26 are folded or buried at the boundary portions with the tie band T), so peeling from the ends of the outer cover cloths 25, 26 at the boundary portions can be effectively suppressed. Furthermore, productivity can be effectively improved in the covering step described later in the manufacturing method section.

[0046] In this example, both outer cover cloths 25, 26 cover the same region of the outer circumferential 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 a covered region. For example, each covered region 25a of the first outer cover cloth (outer outer cover cloth) 25 may be formed to extend further toward the center of the outer circumferential surface than each covered region 26a of the second outer cover cloth (inner outer cover cloth) 26 [in a form in which the covered region 25a (laminated with 26a), the covered region 25a (single layer), the uncovered region 24a, the covered region 25a (single layer), and the covered region 25a (laminated with 26a) are arranged in this order from one side of the outer circumferential surface to the other side]; In one side, the covered region 25a extends further toward the center of the outer circumferential surface than the covered region 26a, and in the other side, the covered region 26a extends further toward the center of the outer circumferential surface than the covered region 25a [in a form in which the covered region 25a (laminated with 26a), the covered region 25a (single layer), the uncovered region 24a, the covered region 26a (single layer), and the covered region 25a (laminated with 26a) are arranged in this order from one side to the other of the outer circumferential surface]. In addition, it is not necessary for all of the outer covering fabrics of the multiple layers to form the covered region.

[0047] For example, a schematic partial cross-sectional view of another example of the wrapped combined V-belt of the present invention is shown in Fig. 7. The wrapped combined V-belt 31 shown in Fig. 7 differs from the wrapped combined 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 the wrapped combined V-belt 21 (or 1). That is, in the wrapped combined V-belt 31 of 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 side, and covers only 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 embodiment, as with the wrapped combined V-belt 21 of FIG. 6, even if the outer cover fabric wears on the side surfaces of the V-belt portion, not only can the multiple layers of outer cover fabric effectively prevent the rubber of the belt body from being exposed, but also the covering region is formed of a single layer of outer cover fabric, so that the flexibility of the belt can be effectively prevented from decreasing. In addition, the material cost of the outer cover fabric can be reduced, which is advantageous in terms of cost.

[0048] Furthermore, if 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 (generated heat and dissipated) due to bending, which tends to improve transmission efficiency.

[0049] In this example, as in the wrapped bonded V-belt 21 (or 1) in FIG. 6 (or FIG. 4), the uncovered region 34a [the exposed portion (exposed surface) of the tensile rubber layer 34)] can come into direct contact with the tie band T, and can be bonded or connected to the tie band T with high adhesive strength by crosslinking. 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 end of the first outer cover fabric 35 located on the outside is folded or buried at the boundary with the tie band T), peeling from the end of the outer cover fabric at the boundary can be effectively suppressed even if the end of the second outer cover fabric (inner outer cover fabric) 36 is not folded. Furthermore, productivity can be effectively improved in the covering process described later in the section on manufacturing method.

[0050] 7 is composed of two layers, a first outermost outer layer (outer outer layer) 35 and a second outer layer (inner outer layer) 36 on the inside thereof, but it is not necessarily required to have two layers, and the inner second outer layer may be laminated in multiple layers. When the inner second outer layer is composed of multiple layers, at least one layer of the second outer layer may form a covering region that covers the outer circumferential surface side 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 cloths (inner outer layer cloths) form a covering region, but only the outermost first outer layer cloth (outer outer layer cloth) forms a covering region. Therefore, it is preferable that one or multiple second outer layer cloths (inner outer layer cloths) do not cover the outer circumferential surface of the belt, but cover at least a part of a region selected from the inner circumferential surface and both side surfaces of the belt (preferably the inner circumferential surface and both side surfaces of the belt).

[0051] [Outer cover] The outer cover fabric (cover fabric) is made of a conventional fabric. Examples of the fabric include woven fabric, knitted fabric (weft knitted fabric, warp knitted fabric), nonwoven fabric, and other fabric materials. Among these, woven fabrics woven in the form of plain weave, twill weave, satin weave, and other forms, woven fabrics woven at a wide angle of more than 90° and less than 120° between warp and weft threads, knitted fabrics, and the like are preferred, and woven fabrics commonly used as cover fabrics for transmission belts for general industry and agricultural machinery [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 of more than 90° and less than 120°] are particularly preferred. Furthermore, in applications requiring durability, wide-angle canvas may be used.

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

[0053] Examples of fibers that make up 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; natural fibers such as cellulose fibers (cellulose fibers, cotton, cellulose derivative fibers, etc.), 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, a blended yarn of polyester-based fibers and cellulosic fibers is preferred from the viewpoints of excellent mechanical properties and economic efficiency.

[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] The cellulose-based fibers include cellulose fibers (cellulose fibers derived from plants, animals, bacteria, etc.) and fibers of cellulose derivatives. Examples of cellulose fibers include cellulose fibers (pulp fibers) derived from natural plants such as wood pulp (coniferous and broadleaf pulp, etc.), bamboo fibers, sugarcane fibers, seed hair fibers (cotton fibers (cotton linters), 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 fibers; algae cellulose, etc. Examples of fibers of cellulose derivatives include cellulose ester fibers; regenerated cellulose fibers (rayon, cupra, lyocell, etc.); and the like.

[0057] The mass ratio of the polyester fibers to the cellulosic fibers is, for example, the former / latter=90 / 10 to 10 / 90, preferably 80 / 20 to 20 / 80, and more preferably 70 / 30 to 30 / 70 (particularly 60 / 40 to 40 / 60).

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

[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 , and 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 cover fabric may be subjected to a conventional adhesive treatment (or surface treatment) [e.g., treatment with a treatment liquid containing an adhesive component] in order 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 (rubber latex or rubber cement, etc.), and RFL liquids containing resorcin (R), formaldehyde (F), and rubber or latex (L) [e.g., RFL liquids in which resorcin (R) and formaldehyde (F) form a condensate (RF condensate) and contain a rubber component such as vinylpyridine-styrene-butadiene copolymer rubber]. These may be used alone or in combination of two or more kinds, and may be treated successively multiple times with the same or different adhesive components.

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

[0063] The adhesive treatment using a rubber component may be, for example, an adhesive treatment such as a treatment of soaking (immersing) the fabric in a rubber paste prepared by dissolving a rubber composition containing a rubber component in a solvent, or a treatment of rubbing (rubbing) the solid rubber composition into the fabric. The adhesive treatment may be applied to 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 (rubber composition for adhesive treatment) to be attached to the outer covering fabric 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 necessary. Examples of the additives include 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 , and 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-layered 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 friction coefficient of the outer covering fabric, which is the transmission surface, is, for example, about 0.9 to 1, preferably about 0.91 to 0.96, and more preferably about 0.92 to 0.95. In this specification and claims, the friction coefficient 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 sheet of outer cover fabric so long as it can form a covered region and an uncovered region on the outer circumferential surface side of the belt. From the viewpoint of easier improvement of abrasion resistance, the outer cover fabric may be a multi-layer or multi-layer structure in which multiple sheets of outer cover fabric are laminated (for example, 2 to 5 layers, preferably 2 to 4 layers, more preferably about 2 to 3 layers, and particularly 2 layers). From the viewpoints of productivity, lateral pressure resistance, and the like, 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 cover fabric is too large, productivity may decrease and resistance to lateral pressure may decrease (and therefore durability may decrease). If the number of layers is too small, when manufactured based on the manufacturing method described below, there may be areas on the side surface (transmission surface) of the belt that are not covered with the outer cover fabric during the covering process (rubber may be easily exposed from the side surface), which may decrease productivity and abrasion resistance. In addition, rubber may easily seep out or be exposed from the outer cover fabric that has worn away during belt operation, which may increase the coefficient of friction with the pulley and generate heat (reduction in adhesive strength between the wrapped V-belt portion and the tie band due to heat generation), resulting in decreased durability.

[0070] When the outer cover cloth is a multi-layered structure (multiple sheets of outer cover cloth are laminated), each of the multiple outer cover cloths may cover the same or different regions of the outer surface of the belt body to form a covering region. Furthermore, not all of the multiple layers of outer cover cloths may necessarily form a covering region, as long as at least one layer of outer cover cloth forms a covering region. For example, a first outer cover cloth located on the outermost side (pulley side) may cover at least the outer surface of the belt (form a covering region), and one or more second outer cover cloths (inner outer cover cloths) located inside (belt body side) of the first outer cover cloth (outer outer cover cloth) may cover the outer surface, but it is preferable that they do not cover the outer surface (do not form a covering region) from the viewpoint of belt flexibility and reducing material costs.

[0071] The outer cover fabric covering at least the inner peripheral surface and both side surfaces of the belt is usually formed to extend in the belt length direction. On the outer peripheral surface of the belt, at least the covered area covered by the outer cover fabric and the uncovered area not necessarily need to be formed to extend in the belt length direction, but from the viewpoint of productivity, it is preferable that they are formed to extend in the belt length direction. The fabric forming the outer cover fabric (if the outer cover fabric is made up of multiple layers, the fabric forming each layer) is preferably a continuous fabric without any breaks in the circumferential direction and / or the belt length direction of the belt cross section (cross section perpendicular to the belt length direction). In other words, the fabric forming the outer cover fabric is preferably a continuous fabric capable of covering at least the inner peripheral surface and both side surfaces of the belt [preferably, at least one side portion (particularly both sides) of the outer peripheral surface] over the entire length of the belt length direction.

[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), it is a single piece of fabric that can be wound up independently, and may have joints (connections), etc.; for example, it 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 length direction of the belt (preferably both sides, as this makes it easier to achieve both adhesion to the tie band and productivity). 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 surface of the belt, i.e., that the ends of the outer covering fabric covering the side surface of the belt are folded or buried at the boundary with the tie band, since this effectively prevents the ends of the outer covering fabric from peeling off from the boundary.

[0074] The area ratio of the uncovered region may be, for example, about 1 to 99% (for example, 15 to 97%, preferably 25 to 95%), or about 10 to 90% (for example, 20 to 90%), more preferably about 25 to 85% (for example, 26 to 83%), and even more preferably about 30 to 80% (for example, 40 to 70%), but from the viewpoint of an excellent balance of adhesion to the tie band, abrasion resistance (particularly, ease of suppressing peeling of the outer cover fabric at the boundary with the tie band), and productivity (particularly, workability and high yield in the covering step), particularly preferably 50 to 90% (for example, 55 to 85%, preferably 60 to 80%, and even more preferably 65 to 75%). The above-mentioned area ratio may be the area ratio in an embodiment in which the outer cover 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 circumferential 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 about 45 to 96% (e.g., 50 to 95%, preferably 55 to 85%, and particularly preferably about 60 to 80%), even more preferably about 60 to 95% (e.g., 65 to 93%, preferably 65 to 75%), and particularly 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 (particularly, ease of preventing peeling of the outer fabric at the boundary with the tie band), and productivity (particularly, workability and high yield in the covering step), the uncovered region may be particularly preferably about 50 to 90% (e.g., 55 to 85%, preferably 60 to 80%, and 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 manufactured based on the manufacturing method described below, it may become difficult to align the outer cover cloth with respect to the belt main body in the covering process, and there is a risk that areas on the belt side (transmission surface) that are not covered by the outer cover cloth may easily occur (reduced productivity).In a wrapped combined 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, causing uneven characteristics or properties in the circumferential direction, and there may be a risk of a significant decrease in wear resistance and noise resistance, making it impossible to use the wrapped combined V-belt. However, when the outer covering fabric is made of multiple layers, even if the proportion of uncovered areas is relatively high, there is a tendency to effectively prevent the occurrence of areas that are not covered by the outer covering fabric (which would result in reduced productivity).

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

[0076] [Belt body] The belt body is covered with an outer covering cloth on the inner peripheral surface, both side surfaces, and a part of the outer peripheral surface to form a wrapped V-belt portion. For example, the wrapped V-belt portion may be a V-belt (V-belt portion) including an endless belt body (belt body portion) having a V-shaped cross section, an inner compressed rubber layer, an outer tensile rubber layer, and a core layer (bonded rubber layer) with a core wire embedded therein, and the outer covering cloth (cover cloth) covering the periphery of the V-shaped cross section of the belt body over the entire length in the belt length direction (belt circumferential direction), and the left and right side surfaces of the V-shaped cross section covered with the outer covering cloth are friction transmission surfaces. In the V-shaped cross section, the side with a wider belt width is the outer peripheral side, and the side with a narrower belt width is the inner peripheral side. If necessary, the inner peripheral surface side of the compressed rubber layer may include a reinforcing cloth layer formed along the belt length direction.

[0077] On the outer peripheral surface side (surface of the tensile rubber layer) of the wrapped V-belt portion (belt main body), an uncovered area that is not covered with the outer covering fabric is formed, exposing the tensile rubber layer, and this exposed tensile rubber layer can be firmly adhered or bonded to the tie band during crosslinking (the connecting process in the manufacturing method described later), 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] Rubber component The rubber component in the crosslinked rubber composition forming the tension rubber layer can be selected from known vulcanizable or crosslinkable 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 a mixed polymer of hydrogenated nitrile rubber and an unsaturated carboxylic acid metal salt)], olefin rubbers [e.g., ethylene-α-olefin rubbers (ethylene-α-olefin elastomers), polyoctenylene rubbers, ethylene-vinyl acetate copolymer rubbers, chlorosulfonated polyethylene rubbers, alkylated chlorosulfonated polyethylene rubbers, epichlorohydrin rubbers, acrylic rubbers, silicone rubbers, urethane rubbers, fluororubbers, etc. These rubber components can be used alone or in combination of two or more.

[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 the crosslinking agent (or vulcanizing agent) and the crosslinking accelerator (or vulcanization accelerator) are easily diffused. In particular, when used in a high-load environment such as a variable speed belt, chloroprene rubber and EPDM are preferred because they have an excellent balance of mechanical strength, weather resistance, heat resistance, cold resistance, oil resistance, adhesiveness, and the like. The chloroprene rubber may be of a sulfur-modified type or a non-sulfur-modified type. In addition, ethylene-α-olefin elastomers such as EPDM are particularly preferred because they have better heat resistance and weather resistance than chloroprene rubber, and can be highly filled with reinforcing agents, making it easy to increase the mechanical strength. Ethylene-α-olefin elastomers such as EPDM tend to have lower adhesiveness than chloroprene and the like, and are prone to peeling off 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, it can be bonded to the tie band with high adhesive strength and peeling of the tie band can be effectively suppressed.

[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 mass% or more (particularly, about 80 to 100 mass%), and 100 mass% (only ethylene-α-olefin elastomer such as EPDM) is particularly preferred.

[0082] In the ethylene-α-olefin elastomer, the ethylene content (the 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 about 45 to 55% by mass. If the ethylene content is too high, there is a risk that the processability and crack resistance will decrease.

[0083] In the present application, the ethylene content means the mass ratio of ethylene units in all units constituting the ethylene-α-olefin elastomer, and can be measured by a conventional method, but may be a ratio 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), that is, 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, more preferably 50 / 50 to 70 / 30, and even more preferably about 50 / 50 to 60 / 40.

[0086] The diene content (particularly, the ethylidene norbornene content) of the ethylene-α-olefin elastomer (particularly, the 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%, more preferably 3 to 7 mass%, and most preferably about 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 the processability and crack resistance are reduced.

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

[0089] In this application, the Mooney viscosity [ML(1+4)125°C] can be measured by a method conforming to 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 operation time is 4 minutes. The Mooney viscosity is used as an index of the fluidity (ease of processing) of rubber by filling an uncrosslinked ethylene-α-olefin elastomer in a cavity so that it is in contact with a rotor with 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 means an average value based on the mass ratio (average Mooney viscosity). In other words, 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.

[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 assistants (or vulcanization assistants), 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 paraffin-based oils and naphthenic oils), processing agents or processing assistants (for example, fatty acids such as stearic acid, fatty acid metal salts such as metal stearates, fatty acid amides such as stearic acid amide, 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.], The composition may contain, for example, an organic solvent, an ether-based plasticizer, an ether-based plasticizer, an ether ester-based plasticizer, etc.], an adhesion improver [for example, a resorcinol-formaldehyde co-condensate (RF condensate), an amino resin (a condensate of a nitrogen-containing cyclic compound and formaldehyde, for example, a melamine resin such as hexamethylol melamine, hexaalkoxymethyl melamine (hexamethoxymethyl melamine, hexabutoxymethyl melamine, etc.), a urea resin such as methylol urea, a benzoguanamine resin such as methylol benzoguanamine resin, etc.), a co-condensate thereof (resorcinol-melamine-formaldehyde co-condensate, etc.)], a tackifier, a coupling agent (a silane coupling agent, etc.), an antiaging agent (an antioxidant, a heat antiaging agent, a flex crack inhibitor, an ozone degradation inhibitor, etc.), a stabilizer (an ultraviolet absorber, a heat stabilizer, etc.), a flame retardant, a colorant, a lubricant, an antistatic agent, 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 cocondensate and the amino resin may be an initial condensate (prepolymer) of a nitrogen-containing cyclic compound such as resorcinol and / or melamine with formaldehyde.

[0092] Examples of the filler include carbon black, silica, clay, calcium carbonate, talc, and mica. The filler often contains a reinforcing filler, and such a reinforcing filler may be carbon black, silica (reinforcing silica), and the like. In addition, the reinforcing property of silica is usually smaller than that of carbon black. These fillers can be used alone or in combination of two or more. 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, and it is particularly preferred to contain a combination of carbon black and silica.

[0093] Carbon black is classified by ASTM as "N0**" to "N9**" (classified based on iodine adsorption), and has 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 diameters, are called hard carbon, and N550 (FEF), N660 (GPF), N762 (SRF), etc., which have large primary particle diameters, are sometimes called soft carbon. These carbon blacks can be used alone or in combination of two or more kinds. Of these, SRF, ISAF, and HAF are preferred, and soft carbon such as SRF is more preferred.

[0094] The average primary particle diameter 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 diameter 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 amount of carbon black can be selected, for example, within the range of about 50 to 500 mL / 100 g, and may be preferably 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 amount of carbon black may be, for example, 5 to 200 g / kg, preferably 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 150m 2 / g (e.g. 20~120m 2 / g), more preferably 25 to 40m 2 / g.

[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 into dry white carbon, wet white carbon, colloidal silica, precipitated silica, etc., depending on the manufacturing method. These silicas can be used alone or in combination of two or more. Among these silicas, silica having a surface silanol group (anhydrous silicic acid, hydrous silicic acid) is preferred, and hydrous silicic acid having many surface silanol groups has a strong chemical bond with the rubber component.

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

[0103] The ratio of the filler (particularly the reinforcing filler) may be, for example, 10 to 100 parts by mass, preferably about 20 to 80 parts by mass (for example, 50 to 70 parts by mass) relative to 100 parts by mass of the rubber component. The ratio of the reinforcing filler may be, for example, 50% by mass or more, preferably 75% by mass or more (for example, 80% by mass or more), more preferably 90% by mass or more, and may be 100% by mass relative to the total filler. The ratio of the carbon black (particularly the soft carbon) may be, for example, 0 to 100 parts by mass (for example, 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 ratio of the silica may be, for example, 0 to 100 parts by mass (for example, 10 to 90 parts by mass), preferably about 25 to 75 parts by mass (for example, 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 easily peel off.

[0104] Examples of the short fibers include the fibers exemplified as fibers constituting the fabric in the section on the outer cover fabric. These short fibers can be used alone or in combination of two or more. Among these short fibers, polyester fibers (polyalkylene arylate fibers such as PET fibers), cellulosic fibers (cotton, etc.), or combinations thereof are preferred. When combining polyester fibers (polyalkylene arylate fibers such as PET fibers) and cellulosic fibers (cotton, etc.), the ratio of the two may be, for example, the former / latter (mass ratio) = 50 / 50 to 80 / 20, 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. 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 (for example, 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 kinds, and the short fibers may be treated successively a plurality of times 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 a 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 about 0 to 30 parts by mass (particularly, 0 part by mass) relative to 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] As the crosslinking agent (or vulcanizing agent), a conventional component can be used depending on the type of rubber component, and examples thereof include organic peroxides (diacyl peroxides, peroxy esters, dialkyl peroxides, preferably dialkyl peroxides such as 1,3-bis(t-butylperoxyisopropyl)benzene, etc.), sulfur-based vulcanizing agents (for example, powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, sulfur chlorides (sulfur monochloride, sulfur dichloride, etc.), preferably powdered sulfur, etc.). 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, from the viewpoint of easily improving the adhesive strength (or peel strength) with the tie band, and a combination of an organic peroxide and a sulfur-based vulcanizing agent is more preferable.

[0110] The ratio of the crosslinking agent (or vulcanizing agent) may be selected from the range of, for example, about 1 to 20 parts by mass (for example, 1.5 to 10 parts by mass) in terms of solid content relative to 100 parts by mass of the rubber component, depending on the type of the crosslinking agent (or vulcanizing agent) and the rubber component, and may be preferably about 2 to 8 parts by mass (for example, 4 to 7 parts by mass). The ratio of the organic peroxide may be, for example, about 0 to 10 parts by mass (for example, 1 to 8 parts by mass), preferably about 3 to 7 parts by mass, in terms of solid content relative to 100 parts by mass of the rubber component. The ratio of the sulfur-based vulcanizing agent may be, for example, about 0 to 5 parts by mass (for example, 1 to 3 parts by mass), preferably about 0.3 to 0.7 parts by mass, in terms of solid content relative to 100 parts by mass of the rubber component. When both the organic peroxide and the sulfur-based vulcanizing agent are combined, the ratio of the two may be, for example, the former / the latter (mass ratio) = 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-vulcanizing agent) include known crosslinking aids, such as polyfunctional (iso)cyanurates [e.g., triallyl isocyanurate (TAIC), triallyl cyanurate (TAC), etc.], polydiene (e.g., 1,2-polybutadiene, etc.), 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, etc.), guanidines (e.g., diphenyl guanidine, etc.), polyfunctional (meth)acrylates [e.g., alkanediol di(meth)acrylate such as ethylene glycol di(meth)acrylate and butanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetraacetate, etc., alkane polyol poly(meth)acrylates such as cyclohexyl (meth)acrylate, bismaleimides (aliphatic bismaleimides such as alkylene bismaleimides such as N,N'-1,2-ethylene dimaleimide, N,N'-hexamethylene bismaleimide, 1,6'-bismaleimide-(2,2,4-trimethyl)cyclohexane; arene bismaleimides or aromatic bismaleimides such as N,N'-m-phenylene dimaleimide, 4-methyl-1,3-phenylene dimaleimide, 4,4'-diphenylmethane dimaleimide, 2,2-bis[4-(4-maleimidophenoxy)phenyl]propane, 4,4'-diphenylether dimaleimide, 4,4'-diphenylsulfone dimaleimide, 1,3-bis(3-maleimidophenoxy)benzene, etc.). 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 ratio of the co-crosslinking agent (crosslinking assistant) such as bismaleimides may be, for example, 0.1 to 15 parts by mass (e.g., 0.5 to 1.5 parts by mass), preferably 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 assistant) (especially bismaleimides) is too small, it may be difficult to improve the mechanical properties.

[0113] Examples of crosslinking accelerators (or vulcanization accelerators) include thiuram accelerators [e.g., tetramethylthiuram monosulfide (TMTM), tetramethylthiuram disulfide (TMTD), tetraethylthiuram disulfide (TETD), tetrabutylthiuram disulfide (TBTD), dipentamethylenethiuram tetrasulfide (DPTT), N,N'-dimethyl-N,N'-diphenylthiuram disulfide, etc.], thiazole accelerators [e.g., 2-mercaptobenzothiazole, 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 proportion of the crosslinking accelerator (or vulcanization accelerator), calculated as solid content, relative to 100 parts by mass of the rubber component may be, 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.

[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), preferably about 3 to 7 parts by mass, calculated as solid content per 100 parts by mass of the rubber component.

[0116] The ratio 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 the softener (especially oils such as paraffin-based oil) is too small, the adhesion may decrease, and the tie band or the 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, not more than 10 parts by mass (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 resorcinol-formaldehyde co-condensate or hexamethoxymethylmelamine) may be, 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, calculated as solid content per 100 parts by mass of the rubber component.

[0119] Examples of the antiaging agent include benzimidazole-based antiaging agents (2-mercaptobenzimidazole (MBI), 2-mercaptomethylbenzimidazole, or metal salts thereof such as zinc salt, etc.), and aromatic secondary amine-based antiaging agents (for example, 4,4'-dioctyldiphenylamine (ODPA), 4,4'-bis(α,α-dimethylbenzyl)diphenylamine (DCD), etc.). These antiaging agents can be used alone or in combination of two or more kinds. 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, 0.5 to 10 mm (eg, 0.5 to 1.5 mm), preferably 0.6 to 5 mm, and more preferably 0.7 to 3 mm (particularly 1 to 2 mm), and may be appropriately adjusted depending on the number of layers of the outer covering fabric, etc.

[0122] (Compressed rubber layer) The compression 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 forming the compressed 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 forming the compressed rubber layer is preferably the same type (particularly the same) of rubber component as the crosslinked rubber composition forming the tension rubber layer.

[0124] 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 tensile rubber layer may be the same or different from each other. 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) in order to suppress the compression deformation of the belt against the pressure from the pulley (from the viewpoint of improving the 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 necessary. When the compressed rubber layer is formed of multiple layers, it may be preferably formed of two layers, a first compressed rubber layer on the outer circumferential side of the belt [the core layer (adhesive rubber layer) side] and a second compressed rubber layer on the inner circumferential side, from the viewpoint of productivity. When the compressed rubber layer is 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 circumferential side of the belt [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 circumferential 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 [e.g., filler, short fibers, crosslinking agents (or vulcanizing agents), co-crosslinking agents or crosslinking aids (or vulcanization aids), crosslinking accelerators (or vulcanization accelerators), metal oxides, softeners, processing agents or processing aids, plasticizers, 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 appropriately adjusted depending on the number of layers of the outer cover fabric, etc. When the compressed rubber layer has a two-layer structure, the average thickness of the first compressed rubber layer on the outer circumferential side 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 body, and may be a core layer formed only of a core body as described above. In this application, when the core layer is formed only of a core body, the core body arranged at intervals in the belt body is referred to as the core body layer, and such a core body layer includes not only a form in which the core body 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 body 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] In addition, 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 peeling between layers 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 body The cores contained in the core layer are preferably cords (twisted cords) arranged at a predetermined interval in the belt width direction. The cords are arranged extending in the belt length direction, and are usually arranged extending in parallel with the belt length direction at a predetermined pitch. When the cores (cords) are embedded in the bonded rubber layer, it is sufficient that a part of the cores is embedded in the bonded rubber layer, and from the viewpoint of improving durability, the cores may be embedded in the bonded rubber layer (the entire cores are completely embedded in the bonded rubber layer).

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

[0132] Among these fibers, ethylene terephthalate, ethylene-2,6-naphthalate, and other C fibers are preferred due to their 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 1000 to 3000 dtex (e.g., 1200 to 2000 dtex). The multifilament yarn may contain, for example, about 100 to 3000 filaments (e.g., 500 to 2000 filaments), and preferably about 700 to 1300 filaments.

[0134] The core wire may usually be a twisted cord (e.g., double twist, single twist, Lang twist, etc., preferably double 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 factor of the first twisted yarn of the twisted cord may be, for example, about 2 to 4 (eg, 2.5 to 3.5), and the twist factor of the second twisted yarn may be, for example, about 2 to 4 (eg, 2.5 to 3.5).

[0135] When the core wire 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] in order to improve adhesion to the crosslinked rubber composition forming 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 types, and may be treated successively multiple times with the same or different adhesive components.

[0136] The adhesive 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.

[0137] Examples of the rubber component in the crosslinked rubber composition forming 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 forming the adhesive rubber 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 and / or the compression rubber layer.

[0138] 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 (eg, 0.3 to 3 mm), preferably about 0.3 to 2 mm (eg, 0.5 to 1.5 mm), and may be appropriately adjusted depending on the number of layers of the outer covering fabric.

[0140] (Reinforcing fabric layer) The belt body may include a reinforcing fabric layer laminated on the inner circumferential surface (inner peripheral surface) side of the compressed rubber layer, if necessary. 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, if necessary.

[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 cover 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 liquid containing an adhesive component] in order to improve adhesion to the compressed rubber layer and the outer cover fabric. 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 cover fabric. These may be used alone or in combination of two or more, and may be treated multiple times in sequence with the same or different adhesive components. A preferred fabric is a fabric having a rubber component attached thereto, and may be a fabric that has been subjected to an adhesive treatment such as a treatment of soaking (immersing) the fabric in a rubber paste prepared by dissolving a rubber composition containing a rubber component in a solvent, or a treatment of rubbing (rubbing) the solid rubber composition into the fabric, and the rubber composition may be the same as the rubber composition in the section on the outer cover fabric, including preferred embodiments. The adhesive treatment may be performed on at least one surface of the fabric, and it is preferable to treat at least the surface that comes into contact with the compressed rubber layer, and it is particularly preferable to treat 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 the abrasion resistance may decrease, and if it is too thick, the flexibility of the belt may decrease.

[0144] [Tie band (connecting member)] The tie band may be a tie band of a conventional combined V-belt, and examples of the tie band 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), or a net (a net-like structure or mesh), or a combination of these. It is preferable that the tie band contains at least a fiber, since it can effectively prevent the wrapped combined V-belt from breaking.

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

[0146] The tie band containing fibers may be, for example, a rubber composition containing short fibers (for example, 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 a fiber structure, and may 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 bending (flexibility) in the belt length direction, and also has an excellent balance with productivity.

[0148] Among woven sudare fabrics, sudare fabrics containing a plurality of filaments extending in the belt width direction are preferred in terms of improving resistance to tensile forces acting in the belt width direction, and it is particularly preferred to use woven 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, a filament extending in the belt width direction means a filament extending approximately parallel to the belt width direction. Furthermore, "approximately parallel" means that the angle between the extension direction of the filament 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 thread density of the first filament (number of threads per 5 cm in the belt length direction) is, for example, 10 to 300 threads / 50 mm, preferably 50 to 200 threads / 50 mm, further preferably 80 to 180 threads / 50 mm, further preferably 100 to 150 threads / 50 mm, and most preferably 110 to 130 threads / 50 mm.

[0151] The yarn density of the second filament is, for example, 1 to 30 yarns / 50 mm, preferably 2 to 10 yarns / 50 mm, further preferably 2 to 8 yarns / 50 mm, more preferably 3 to 7 yarns / 50 mm, and most preferably 4 to 6 yarns / 50 mm.

[0152] Examples of the fibers constituting the first and second filaments include the fibers exemplified as fibers constituting the fabric in the section on the outer cover fabric. Of the fibers, the first filament is preferably a polyester fiber or a polyamide fiber, and more preferably an aliphatic polyamide fiber such as polyamide 66 fiber. The second filament is preferably a cellulose fiber, and more preferably a cellulose fiber such as cotton fiber.

[0153] When the first filament is a polyester fiber or a polyamide fiber, the fineness of the first filament (total fineness when it is 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 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] in order to improve adhesion to a rubber component (crosslinked rubber composition) etc. 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 kinds, and may be treated successively multiple times with the same or different adhesive components.

[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 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 standpoint of preventing peeling of the fiber structure as well as preventing interlayer (interlayer peeling with the wrapped V-belt portion and / or the protective layer) peeling and preventing breakage (including preventing the propagation of defects), it is preferable for the fiber structure to be sandwiched between a rubber composition containing a rubber component (rubber sandwiched between the connecting reinforcement layers) (the fiber structure is embedded in a crosslinked rubber composition).

[0158] Examples of the rubber component constituting the crosslinked rubber composition of the linked 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 linked reinforcement layer is preferably the same type (e.g., the same) of rubber component as 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 of deterioration in processability and crack resistance.

[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, the 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 the processability and crack resistance are reduced.

[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), and preferably about 35 to 55 (e.g., 40 to 50). If the Mooney viscosity is too high, there is a risk of the processability and crack resistance decreasing.

[0163] In this application, the Mooney viscosity [ML(1+4)100°C] can be measured by a method conforming to 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 by filling an uncrosslinked ethylene-α-olefin elastomer in a cavity so that it is in contact with a rotor with grooves on its surface, and measuring the torque required to rotate the rotor.

[0164] In addition to the rubber component, the crosslinked rubber composition of the link reinforcement layer may or may not contain conventional additives 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, and antioxidants. These may be used alone or in combination of two or more.

[0165] As the filler in the crosslinked rubber composition of the connection reinforcing layer, reinforcing fillers such as carbon black (hard carbon such as HAF) and silica are preferred. The ratio of the filler (particularly the reinforcing filler) may be, for example, 30 to 80 parts by mass, preferably about 40 to 70 parts by mass (for example, 50 to 60 parts by mass) relative to 100 parts by mass of the rubber component. The ratio of the reinforcing filler may be, for example, 50% by mass or more, preferably 75% by mass or more (for example, 80% by mass or more), more preferably 90% by mass or more, or may be 100% by mass, relative to the total filler. The ratio of the carbon black (particularly the hard carbon) may be, for example, 20 to 50 parts by mass (for example, 25 to 45 parts by mass), preferably about 30 to 40 parts by mass, relative to 100 parts by mass of the rubber component. The ratio of the silica may be, for example, 5 to 40 parts by mass (for example, 8 to 35 parts by mass), preferably about 10 to 30 parts by mass (for example, 15 to 25 parts by mass) relative to 100 parts by mass of the rubber component. When both carbon black (particularly hard carbon) and silica are contained, the ratio between them may be, for example, the former / latter (mass ratio)=45 / 55 to 80 / 20, preferably about 55 / 45 to 70 / 30.

[0166] The crosslinking agent (or vulcanizing agent) in the crosslinked rubber composition of the connecting reinforcement layer is preferably a sulfur-based vulcanizing agent. The ratio of the crosslinking 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 the crosslinking agent (or vulcanizing agent) and the rubber component.

[0167] The cross-linking accelerator (or vulcanization accelerator) in the cross-linked rubber composition of the connection reinforcing layer is preferably MBTS, etc. The ratio 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 crosslinked rubber composition of the connection reinforcement layer may be, for example, 1 to 20 parts by mass (eg, 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 connecting reinforcement layer may be, in solid content terms, 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) per 100 parts by mass of the rubber component.

[0170] The proportion of the adhesion improver (such as resorcinol-formaldehyde cocondensate, hexamethoxymethylmelamine, etc.) in the cross-linked rubber composition of the connecting reinforcement layer may be, for example, 0.1 to 20 parts by mass (e.g., 1 to 10 parts by mass), preferably 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 linking 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 it is preferable to use it alone (single layer).

[0173] The average thickness of the connecting reinforcing layer is, for example, about 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 decreasing.

[0174] (protective layer) The tie band (connecting member) may be formed only by 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 the outermost layer) in order to effectively suppress damage to the fiber structure in the connecting reinforcement layer (e.g., damage caused by foreign objects 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 cover 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 crosslinked rubber composition forming the tension rubber layer.

[0177] 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 from each other. 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 decrease, and if it is too thick, the flexibility of the belt may decrease.

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

[0181] [Manufacturing method of wrapped bonded V-belt] A wrapped bonded V-belt is obtained by manufacturing an uncrosslinked (unvulcanized) wrapped V-belt portion (wrapped V-belt portion precursor) and then carrying out a connecting process 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, for example, by the methods described in JP-A-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 wound on the compression rubber layer sheet, a core body is wound on the wound first adhesive rubber layer sheet, and an unvulcanized second adhesive rubber layer sheet and an unvulcanized tension rubber layer sheet are wound on the wound core body in this order in a winding process, a cutting process in which the obtained annular laminate is cut (sliced ​​into rings) on the mantle, a skiving process in which the cut annular laminate is placed on 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 winding process) in which the periphery of the obtained unvulcanized belt main body (belt main body precursor) is covered with an outer cover fabric precursor [for example, an outer cover fabric (fabric) with an uncrosslinked rubber composition attached] to obtain an unvulcanized wrapped V-belt portion (wrapped V-belt portion precursor).

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

[0184] The method for producing a wrapped coupled V-belt of the present invention includes 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 a tie band precursor [e.g., a tie band containing a fiber (particularly a fiber structure) and an uncrosslinked rubber composition], in which the inner peripheral surface and both side surfaces of the belt body precursor are covered in the covering step, and at least a partial region (the uncovered region) of the outer peripheral surface is not covered, and the method does not need to include a removing step (steps described in Patent Documents 2 to 3) of cutting or removing the outer covering fabric precursor covering the outer peripheral surface side of the wrapped V-belt precursor obtained in the covering step. Therefore, a wrapped coupled V-belt that can omit a step, has excellent abrasion resistance, and can suppress peeling of the tie band, can be produced inexpensively with high productivity.

[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, since this allows for even higher productivity.

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

[0187] Conventionally, when covering a belt body precursor with an outer covering fabric precursor, for example as shown in Figure 2, the belt body precursor is wound around two pulleys and rotated (running), and the outer covering fabric precursor wound in a roll is brought into contact (abutment) with the outer surface of the rotating belt body precursor while being fed out, and the outer covering fabric precursor in contact with the outer surface is pressed against a roller so as 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 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 (runs) between two pulleys with the inner and outer circumferential sides reversed from the conventional method (with the wide surface facing the inner circumferential side and the narrow surface facing the outer circumferential 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 length 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 surface on the outer circumferential side of the rotating belt body precursor (the surface that will become the inner circumferential side of the wrapped V-belt portion), and pressed with a roller so as to conform to the shape of the belt body precursor in the same manner as in the conventional method, thereby covering both side surfaces and the wide surface on the inner circumferential side (the surface that will become the outer circumferential side of the wrapped V-belt portion). However, since the width of the outer cover fabric precursor is shorter than the perimeter, at least one side (corresponding to the covered area) is covered on the wide surface on the inner circumferential side (the surface that will become the outer circumferential side of the wrapped V-belt portion) and an area that is not covered (corresponding to the non-covered area) is formed.

[0189] As described above, when a wrapped V-belt precursor having the entire belt outer periphery side as a non-covered region is manufactured using a seamless outer cover fabric precursor, it is considered difficult to align the outer cover fabric precursor (aligning both ends in the width direction of the outer cover fabric precursor with both ends of the outer periphery of the belt body precursor) for the following reasons. First, the outer cover fabric precursor becomes sticky due to the adhesive treatment, so once it is brought into contact with the belt body precursor, it is not possible to correct the position. In addition, since the belt body precursor is an uncrosslinked rubber composition, it is soft and is likely to become distorted in the skiving process. Therefore, when the belt body precursor and the outer cover fabric precursor are brought into contact with each other, it is difficult to make the belt body precursor run straight (it is likely to meander), and it is likely to be misaligned with the outer cover fabric precursor. Furthermore, in the crosslinking molding process (crosslinking molding step) described later, it is considered that the rubber composition flows in the mold due to pressure or the like, causing misalignment. Therefore, when trying to manufacture a wrapped bonded V-belt in which the entire outer periphery of the belt is an uncovered area (the proportion of uncovered area is 100%), it is easy for the side of the belt to be left uncovered by the outer sheath fabric in the lengthwise direction due to the influence of misalignment, 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 peripheral surface and both side surfaces of the belt while folding the end of the outer cover fabric precursor into the side of the outer peripheral surface on at least one side (preferably both sides), not only can the belt side surfaces be effectively prevented from being left uncovered by the outer cover fabric, but the removal step can be eliminated and no material loss occurs, making it possible to simply and efficiently manufacture the wrapped V-belt precursor with high productivity. Moreover, in the resulting wrapped V-belt precursor, not only can the uncovered region improve adhesion to the tie band, but the covered region is formed on at least one side (preferably both sides) of the outer peripheral surface in a form folded in from the side, effectively preventing the outer cover fabric from peeling off from the boundary with the tie band.

[0191] When covering endlessly with a seamless outer covering fabric precursor, 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 cover endlessly.

[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 a 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 along 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 tie bands. The crosslinked sleeve (vulcanized sleeve) thus formed is cut to a predetermined width, thereby forming a wrapped combined 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 according to 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. Each rubber layer sheet containing short fibers can be rolled with a calendar roll or the like to align (orient) the short fibers in the rolling direction.

[0194] The tie band precursor and each uncrosslinked (unvulcanized) wrapped V-belt part (wrapped V-belt part precursor) are bonded to each other by, for example, an adhesive component attached to the tie band precursor or the outer covering fabric precursor of the covered region by an adhesive treatment, and the exposed stretched rubber layer of the uncovered region. For example, when a fabric treated by friction (rubbing) 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 stretched 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 part includes an uncrosslinked (unvulcanized) belt bonding step of bonding a plurality of unvulcanized wrapped V-belt parts to each other via the tie band as a connecting part. The unvulcanized belt bonding step is not limited to this method, and the tie band may be formed by wrapping a plurality of layers of rubber sheets for tie bands (for example, a sheet for a connecting reinforcing layer, a sheet for a protective layer, a laminate of these, etc.).

[0195] The number of wrapped V-belt parts in the wrapped combined V-belt may be 2 or more, for example, 2 to 10, preferably 2 to 8, and more preferably 2 to 6. The adjacent wrapped V-belt parts may be aligned parallel to the belt length direction, and are not limited to an arrangement with an interval as in FIG. 4, and may be arranged without an interval. From the viewpoint of productivity, it is preferable to arrange the adjacent wrapped V-belt parts with an interval. The interval between the adjacent wrapped V-belt parts is, for example, about 1.7 to 4.3 mm, preferably about 2 to 4.1 mm, and more preferably about 2.3 to 3.9 mm. The interval between the wrapped V-belt parts means the interval on the outer circumferential surface of the belt. The tie band may be capable of connecting the wrapped V-belt parts, and is not limited to an arrangement in which the entire outer circumferential surface of the wrapped V-belt parts is contacted with and integrated with the entire outer circumferential surface of the wrapped V-belt parts as in FIG. 4, and the outer circumferential surface of the wrapped V-belt part may have an area that does not contact the tie band. From the standpoint of belt durability, it is preferable that the entire outer circumferential surface of each wrapped V-belt portion be in contact with and integrated with the tie band.

[0196] The wrapped bonded V-belt may be used in high-load, long-span (long center-to-center distance) layouts such as large-scale agricultural machinery. The width of the belt outer circumferential 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 combined V-belt may be, for example, 50 inches or more, 200 inches (508 cm) or more, or may be about 220 to 500 inches.

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

[0199] The wrapped combined V-belt of the present invention is suitable for high-load applications and is therefore suitable for high-horsepower machines, and the load (standard 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 combined 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 bonded V-belt of the present invention has excellent wear resistance. The wear rate of the wrapped bonded 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 combined V-belt of the present invention has excellent resistance to lateral pressure. The ride-out change of the wrapped combined 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 about 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 combined V-belt of the present invention has excellent durability. The durability life of the wrapped combined 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. 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 following describes the raw materials and preparation methods of the rubber composition, cord, outer covering fabric precursor, and connecting reinforcing layer precursor used, the belt preparation method, and the measurement and evaluation methods.

[0209] [Rubber composition] (Materials used) EPDM1: "Nordel IP4520" manufactured by Dow Chemical Company, Mooney viscosity [ML (1+4) 125°C] approx. 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: Hashimoto "cotton cut thread", average fiber length 6mm Polyester staple fiber: "PET cut yarn" made by Koyo staple fiber, average fiber length 3 mm Carbon black SRF: "Seat S" manufactured by Tokai Carbon Co., Ltd., DBP absorption capacity 68 mL / 100 g, BET specific surface area 27 m 2 / g, iodine adsorption capacity 26g / 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 121g / 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 80g / 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 Paraffin oil: "Diana Process Oil PW90" manufactured by Idemitsu Kosan Co., Ltd. Anti-aging agent MBI (2-mercaptobenzimidazole): "Nocrac MB-O" manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Anti-aging agent 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: NOF Corp. "Camellia Stearate" Crosslinking accelerator TMTD (tetramethylthiuram disulfide): "Noccela TT" manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Crosslinking accelerator CBS (N-cyclohexyl-2-benzothiazolyl sulfenamide): "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): "Valnoc 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): SINGH PLASTICISER & RESINS "POWERPLAST PP-1890S" Organic peroxide: 1,3-bis(t-butylperoxyisopropyl)benzene Sulfur (powdered sulfur): Bigen Chemical

[0210] (Preparation of Uncrosslinked Rolled Rubber Sheet and Uncrosslinked Rubber Mass Composition 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 produce uncrosslinked (unvulcanized) rolled rubber sheets of predetermined thicknesses, which were used as sheets for the compression rubber layer, adhesive rubber layer, tension rubber layer and / or protective layer.

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

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

[0213] [Table 1]

[0214] [Core (processing code)] Three aramid fiber bundles of 1670 dtex (1000 filaments) were aligned and twisted in the S direction with a twist factor of 3.0 to produce a first twisted yarn, and five of the first twisted yarns were aligned and twisted in the Z direction with a twist factor of 3.0 to produce a twisted cord (multi-ply yarn) with a total fineness of 25050 dtex (15000 filaments) and a diameter of 1.9 mm, which was then adhesively treated to produce a treated cord, which was used as the core wire. The twist factor TF is a value calculated using 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 cover fabric precursor was a canvas that had been subjected to adhesive and friction treatment (treated canvas). The warp and weft yarns were a 20s / 3 (20 count, 3-ply) blend of polyester fiber and cotton in a mass ratio of 50 / 50, and the fabric was plain woven with a warp density of 75 / 50 mm and a weft density of 75 / 50 mm, resulting in a basis weight of 280 g / m 2The canvas was immersed in RFL liquid (a mixture of 2.6 parts by mass of resorcinol, 1.4 parts by mass of 37% formalin, 17.2 parts by mass of vinylpyridine-styrene-butadiene copolymer latex (manufactured by Zeon Corporation), and 78.8 parts by mass of water), dried, and then subjected to wide-angle treatment so that the angle between the warp and weft threads was 120 degrees. The treated canvas (basis weight approximately 500 g / m2) was obtained by rubbing (friction) rubber composition R1 on both sides of the obtained wide-angle canvas. 2 A 1000mm thick plate was used.

[0218] [Interlocking reinforcement layer precursor (treated sudare)] The blind was subjected to an adhesive treatment and a rubber sheet lamination treatment to obtain a precursor of the connection reinforcing layer. In detail, a blind-like fabric was woven with a warp density of 120 / 50 mm and a weft density of 5 / 50 mm using a single-twisted cord (wire diameter 0.22 mm) made of 470 dtex nylon 66 as the warp thread and a cotton thread (wire diameter 0.1 mm) of No. 40 as the weft thread, and immersed in RFL liquid (a mixture of 2.6 parts by mass of resorcin, 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 a rubber sheet for tie bands of rubber composition R3 was laminated on both sides to obtain a treated blind (thickness about 0.7 mm).

[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 circumference of the compression rubber layer sheet (thickness 5.4 mm) of R1 wound around the outer circumference of the cylindrical drum, and further laminated on the outer circumference of the compression rubber layer sheet (thickness 1.6 mm) of R1 to form a cylindrical uncrosslinked sleeve in which the uncrosslinked rubber layer and the core wire were laminated. That is, the rubber composition R1 was exposed on the outermost circumference of the uncrosslinked sleeve. The obtained uncrosslinked sleeve was cut in the circumferential direction while being placed on the outer circumference of the cylindrical drum, to form a ring-shaped uncrosslinked rubber belt 1.

[0220] (Skive process and outer covering process (covering process)) The uncrosslinked rubber belt 1 was removed from the drum, and both sides of the uncrosslinked rubber belt were cut (skived) at a specified angle to form the cross section of the uncrosslinked rubber belt into a V-shaped cross section (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 wrapped around the outer cover fabric precursor to form the uncrosslinked wrapped V-belt portion 1 (covering 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 periphery of the uncrosslinked rubber belt toward 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 toward the belt length direction), thereby changing the ratio of the uncovered region on the outer periphery (back side) of the wrapped V-belt part after the connecting step (after crosslinking) to the ratio 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 periphery was a single layer, and both ends of the outer covering fabric were formed facing each other on the outer periphery side.

[0222] The outer cover fabric precursor was oriented so that the directions of the warp and weft yarns were each inclined at 60° to the longitudinal direction of the belt.

[0223] (Preparation of Joined V-Belts (Connecting Process)) The six uncrosslinked wrapped V-belt parts 1 obtained were fitted into an annular groove formed in the lower crosslinking mold, and then the treated sudare (connection reinforcement layer precursor) and the protective layer rubber sheet R1 (thickness 1.3 mm) were set as a tie band precursor on the radially outer part. That is, in setting the tie band precursor, the treated sudare and the protective layer rubber sheet were wound in this order along the circumferential direction (belt length direction) of the six uncrosslinked wrapped V-belt parts arranged in the width direction, and the tie band precursor was set on the six uncrosslinked wrapped V-belt parts. The treated sudare was arranged so that the longitudinal direction of the warp yarn was approximately parallel to the belt width direction, and the longitudinal direction of the weft yarn 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 to obtain a crosslinked belt 1 in which six wrapped V-belt portions 1 (ASABE standard HB type, belt length 1600 mm) were connected and bonded with tie bands.

[0225] The obtained crosslinked belt 1 was cut to produce a wrapped bonded V-belt 1 (cross-sectional dimensions: width 54.6 mm×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)) On the outer circumferential surface of the cylindrical drum, the R1 second compressed rubber layer sheet (thickness 3.4 mm), the R2 first compressed rubber layer sheet (thickness 1.5 mm), and the R1 adhesive rubber layer sheet (thickness 0.5 mm) were laminated in this order, and then the core wire was spirally wound, and on the outer circumferential surface, the R1 adhesive rubber layer sheet (thickness 0.5 mm) and the R2 tension rubber layer sheet (thickness 1.1 mm) were laminated in this order to form a cylindrical uncrosslinked sleeve in which the uncrosslinked rubber layer and the core wire were laminated. That is, the rubber composition R2 was exposed on the outermost circumferential surface of the uncrosslinked sleeve. The obtained uncrosslinked sleeve was cut in the circumferential direction while being arranged on the outer circumferential surface of the cylindrical drum, and a ring-shaped uncrosslinked rubber belt 2 was formed. In addition, in the rubber layer R2 containing short fibers, the short fibers were arranged so that the longitudinal direction of the short fibers was approximately parallel to the belt width direction.

[0227] (Skive process and outer covering process (covering process)) An uncrosslinked wrapped V-belt portion 2 was formed in the same manner as in the skiving process and the covering process 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 the ratio of the uncovered region on the outer peripheral surface (back surface) of the wrapped V-belt portion in the covering process was changed to the ratio shown in Table 3 described later. 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 covering 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 covering fabric covering the inner peripheral surface was a single layer, and both ends of the outer covering fabric were opposed to each other on the outer peripheral surface side.

[0228] (Preparation of Joined V-Belts (Connecting Process)) A crosslinked belt 2 in which six wrapped V-belt portions 2 (ASABE standard HB type, belt length 1600 mm) were connected and bonded with tie bands was obtained in the same manner as the connecting process of [Comparative Example 1 and Examples 1 to 6], except that an 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 obtained crosslinked belt 2 was cut to produce a wrapped bonded V-belt 2 (cross-sectional dimensions: width 54.6 mm×thickness 12.7 mm) having three wrapped V-belt portions 2.

[0230] [Examples 10 to 12] A wrapped bonded V-belt having the cross-sectional shape shown in FIG. 6 was manufactured by changing the number of layers of the outer cover fabric in Examples 4 to 6 (tension rubber layer: R1, ratio of non-covered region: 50%, 70% or 90%, number of layers of the outer cover fabric: 1 layer) to two layers. That is, a wrapped bonded V-belt having three wrapped V-belt portions 1 was manufactured in the same manner as in Examples 4 to 6 except that in the covering step, the uncrosslinked rubber belt 1 was covered twice with the outer cover fabric precursor, and the thicknesses of the compressed rubber layer sheet and the tension rubber layer sheet were adjusted to be thinner as the number of outer cover fabric layers increased in order to make the cross-sectional dimensions the same as in Examples 4 to 6. In the covering step, in order to obtain the cross-sectional shape shown in FIG. 6, the outer cover fabric (first outer cover fabric) was covered so that it was aligned with 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 circumferential surface of the belt main body).

[0231] [Examples 13-14] A wrapped bonded V-belt was manufactured by changing the number of layers of the outer cover fabric in Example 11 (tension rubber layer: R1, ratio of non-covered region: 70%, number of layers of the outer cover fabric: 2 layers) to 3 layers (Example 13) or 4 layers (Example 14). That is, a wrapped bonded V-belt having three wrapped V-belt portions 1 was manufactured in the same manner as in Example 11, except that in the covering step, the uncrosslinked rubber belt 1 was wrapped with the outer cover fabric precursor three or four times, and the thicknesses of the compressed rubber layer sheet and the tension rubber layer sheet were adjusted to be thinner as the number of outer cover fabric layers increased in order to make the cross-sectional dimensions uniform. In the covering step, the covering step was performed so that each outer cover fabric was aligned with the adjacent outer cover fabric (so that all the outer cover fabrics covered the same area of ​​the outer peripheral surface of the belt main body) in order to make the cross-sectional shape conforming to FIG. 6.

[0232] [Examples 15 to 16] In the outer covering fabrics in Examples 11 and 12 (tension rubber layer: R1, proportion of uncovered area: 70% or 90%, number of layers of outer covering fabric: 2), the proportion of uncovered area of ​​the inner outer covering fabric (second outer covering fabric) was changed to 100%, and a wrapped bonded V-belt having the cross-sectional shape shown in Fig. 7 was manufactured. That is, in the covering step, in the first cover winding 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, and in the second cover winding process, both sides of the outer peripheral surface were covered so that the proportion of uncovered area of ​​the outer outer covering fabric (first outer covering fabric) was 70% (Example 15) or 90% (Example 16). Except for this, a wrapped bonded V-belt having three wrapped V-belt portions 1 was manufactured in the same manner as in Examples 11 and 12.

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

[0234] [Exposed rubber on the side of the wrapped V-belt] The presence or absence of any area in which the rubber was exposed without being covered with the outer covering fabric was confirmed on the side surface of the wrapped V-belt portion of the wrapped joined V-belt obtained after the connecting step (after crosslinking). The results are shown in the table below.

[0235] [Peel test] The obtained wrapped combined V-belt was cut along the three wrapped V-belt parts (divided into three), and then the peeling force of the tie band was measured. Specifically, a 15 cm length was cut from the cut endless belt in the belt length direction to prepare a peel test sample, and a cut was made between the tie band and the wrapped V-belt part with a blade on the cut surface, and then the tie band and the wrapped V-belt part were pulled in a direction to separate them (peeling angle 180°, i.e., the tie band was folded back 180° with respect to the wrapped V-belt part) with an autograph (Shimadzu Corporation "AGS-J10kN"), and the peeling force when peeled along the belt length direction was measured. The peeling force was determined as a value per 1 cm width by dividing the measured tensile force by the width of the peeling surface [the width of the outer peripheral surface of the wrapped V-belt part (the combined width of the covered area and the uncovered area)].

[0236] The peel test samples were cut out from three arbitrary positions of the cut endless belt, and the arithmetic average of the values ​​(peeling 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 three arbitrary positions in the portion (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 becomes more likely when the peeling force of the tie band becomes less than about 50 N / cm. The results are shown in the table below and in Figure 8.

[0238] [Percentage of uncovered area] From the center of the wrapped V-belt part after the peel test (wrapped V-belt part obtained by peeling off the tie band from the peel test sample), a 3 cm long sample was cut in the belt length direction as an observation sample, and the peeled surface (outer periphery) was observed. Specifically, the peeled surface was photographed with a microscope (Keyence Corp. "VHX-5000"), and the photographed image was analyzed with measurement software (Olympus Corp. "Stream") so that the uncoated area and the coated area were recognized as different areas, and the proportion of the uncoated area was calculated from the area ratio of each area.

[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 ​​obtained from the three samples (percentage of the uncoated area) was adopted. The results are shown in the table below.

[0240] [Ride-out change amount] The wrapped bonded V-belt was hung around a pair of pulleys with a diameter of 113 mm in an atmosphere of 80°C, and an axial load of 500N 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 2000N, and the amount of change in the position of the back surface of the belt (ride-out change amount) was measured. It can be determined that the smaller the ride-out change amount, the better the lateral pressure resistance. The results are shown in the table below.

[0241] [Wear rate] As shown in Figure 9, a two-axis running test machine consisting of a driving (Dr.) pulley with a diameter of 180 mm and a driven (Dn.) pulley with a diameter of 180 mm was used to evaluate the wear resistance. In detail, a wrapped combined V-belt was hung on each pulley, and the belt was run for 96 hours at an ambient temperature of 23°C with an axle load of 1600 N, a driving pulley rotation speed of 1800 rpm, and a load on the driven pulley of 53 N m. The mass of the belt was measured before and after the run, and the mass change rate (wear rate) was evaluated using the following formula. It can be determined that the smaller the wear rate, the better the wear resistance. The results are shown in the table below.

[0242] Wear rate (%) = [(W0-W1) / W0] x 100

[0243] [In the formula, W0 represents the mass (g) of the belt before running, and W1 represents the mass (g) of the belt after running.]

[0244] [Durable life] As shown in Figure 10, a three-axis running test machine equipped with a driving (Dr.) pulley with a diameter of 100 mm, a driven (Dn.) pulley with a diameter of 100 mm, and a back tension (Ten.) pulley with a diameter of 85 mm was used to evaluate the durability of the wrapped bonded V-belt. In detail, the wrapped bonded V-belt was hung on each pulley, the contact angle of the belt with respect to the back tension pulley was adjusted to 20 degrees, and then a load of 588 N was applied to the driven pulley, the driving 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 lifespan was reached. The running time [unit: h (hours)] was defined as the durability lifespan. The lifespan of the belt was defined as the point at which the tie band 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] [Table 2]

[0246] [Table 3]

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

[0248] [Table 4]

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

[0250] Examples 10 to 12 are examples in which the outer covering fabric in Examples 4 to 6 was changed to two layers, and as in Examples 4 to 6, the peeling force increased as the area ratio of the uncovered region increased. On the other hand, in Example 6 (90%) in which the area ratio of the uncovered region was large, 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), whereas in Example 12 in which the outer covering fabric was two layers, even if rubber was exposed on the side in the first cover winding process, the exposed areas could be covered by the second cover winding process, so that the wrapped V-belt was manufactured without exposing rubber from the side despite the large area ratio of the uncovered region. In addition, the rideout change amount and wear rate of Examples 10 to 12 were approximately the same, but the durable life was particularly high in Examples 11 to 12 in which the area ratio of the uncovered region was large.

[0251] Examples 13 to 14 are examples in which the outer covering fabric in Example 5 is changed to three or four layers. Comparing Examples 5, 11, 13, and 14, which have different numbers of layers of the outer covering fabric, the wear rate was about the same in all cases, but the ride-out change tended to increase with an increase in the number of layers (the belt is more likely to fall into the pulley when tension is applied, and the lateral pressure resistance tends to decrease), and in Examples 13 to 14 (especially Example 14), which have three or four layers of the outer covering fabric, the lateral pressure resistance was significantly decreased. The reason for this is unclear, but it is presumed to be due to a relative decrease in the proportion of the belt main body part (hard rubber part) that is harder than the outer covering fabric due to an increase in the number of layers of the outer covering fabric. In Examples 13 to 14, in which the lateral pressure resistance was thus decreased, the durability life tended to be somewhat decreased, possibly because a force was easily applied in the direction of peeling from the tie band when the wrapped V-belt part fell toward the center of the pulley during running.

[0252] On the other hand, Example 5, which had one outer covering fabric layer, had the smallest ride-out change and excellent side pressure resistance, and the peeling force and wear rate were similar to those of Example 11, but Example 11, which had two outer covering fabric layers, had a better durability life. The reason for this is unclear, but it is thought that Example 5, which had only one outer covering fabric layer, was influenced by the fact that the rubber of the belt body was easily exposed or exuded from the worn areas of the outer covering fabric, even though the wear rate was similar. In other words, it is presumed that the exposure or exudation of the rubber that occurred during belt running increased the coefficient of friction between the pulley, and the resulting large heat generation reduced the adhesive strength at the joint with the tie band, making it easier to peel off from the tie band.

[0253] Therefore, Example 11, which had two layers of outer covering fabric, effectively suppressed the exposure or seepage of rubber while also exhibiting excellent resistance to lateral pressure, and thus had the longest durability among Examples 5, 11, 13, and 14.

[0254] [Table 5]

[0255] Examples 15 to 16 are examples in which the ratio of the uncovered area of ​​the inner outer cover fabric (second outer cover fabric) of the two-layer outer cover fabric in Examples 11 to 12 is changed to 100%. That is, in Examples 11 to 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 to 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. Examples 15 to 16 showed high peeling force, similar to Examples 11 to 12. Moreover, in Examples 15 to 16, 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 the wear rate was kept low and the durability life was excellent, probably because peeling of the outer cover fabric at the boundary between the side surface of the wrapped V-belt portion and the tie band could be suppressed even after running (after evaluation of the wear rate and durability life).

[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. In Example 16, even if the area ratio of the uncovered region was large, the wrapped V-belt portion could be manufactured without exposing the rubber from the side surface, similar to Example 12. The rideout change and wear rate were approximately the same 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] Reference Example 2 is an example in which the ratio of the uncovered area of ​​not only the inner outer cover fabric (second outer cover fabric) but also the outer outer cover fabric (first outer cover fabric) was changed to 100%, i.e., an example in which neither the inner nor outer cover fabric formed a covered area. Although Reference Example 2 exhibited high peeling force, the wear rate was high and the durability life was short, probably because the rubber was exposed on the side of the wrapped V-belt portion of the belt immediately after manufacture and the outer cover fabric was easily peeled off at the boundary between the side of the wrapped V-belt portion and the tie band during running (during evaluation of wear rate and durability life).

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

[0259] The wrapped coupled V-belt of the present invention can be used in general industrial machines such as compressors, generators, and pumps, and agricultural machines such as combine harvesters, rice planters, and mowers. It may also be used in high-load machines used in long-span layouts under high loads, such as large agricultural machines 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. [Explanation of symbols]

[0260] 1,11,21,31…Wrapped joint V-belt V…Wrapped V-belt section 2,12,22,32…Compressed rubber layer 3, 13, 23, 33...Core layer (core, adhesive rubber layer) 4, 14, 24, 34...Tension rubber layer 4a,14a,24a,34a...Uncovered area 5, 15, 25, 35...Outer cover (first outer cover or outer cover) 26, 36...Outer cover fabric (second outer cover fabric or inner outer cover fabric) 5a,15a,25a,26a,35a...Covered area T…Tie band

Claims

1. A wrapped joint V-belt including a plurality of wrapped V-belt portions, each having a belt body portion covered with an outer covering fabric, and a tie band connecting the plurality of wrapped V-belt portions on an outer peripheral surface of each wrapped V-belt portion, The outer peripheral surface of the wrapped V-belt portion has a covered region covered with the outer covering fabric and an uncovered region that is not covered, A wrapped bonded V-belt, wherein the covering region is formed on at least one side of the outer circumferential surface, and an outer cover fabric covering the covering region also covers a side surface of the wrapped V-belt portion.

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

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

4. 3. The wrapped coupled V-belt according to claim 1, 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. 3. The wrapped, bonded V-belt according to claim 1, wherein the belt body is covered with one to three layers of outer covering fabric.

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

7. The belt body is covered with a plurality of layers of outer covering fabric, Among the multiple layers of outer cover fabrics, a first outer cover fabric located at the outer periphery forms the covering region, 3. The wrapped, connected V-belt according to claim 1, wherein one or more second outer cover fabrics positioned on the inner side of the first outer cover fabric do not cover the outer circumferential surface.

8. 3. The wrapped, bonded V-belt of claim 1 or 2, wherein the tie band comprises at least a fiber.

9. a covering step of covering the belt body precursor with an outer cover fabric precursor to form a wrapped V-belt precursor; a connecting step of connecting outer circumferential surfaces of the plurality of wrapped V-belt portion precursors obtained in the covering step with a tie band precursor, 3. The method for manufacturing a wrapped bonded V-belt according to claim 1, wherein in the covering step, the inner peripheral surface and both side surfaces of the belt body precursor are covered, at least one side portion of the outer peripheral surface is covered with an outer covering fabric precursor that covers the side surfaces, and a part of the outer peripheral surface is not covered.

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

11. 10. The manufacturing method according to claim 9, wherein in the covering step, a width of the outer cover fabric precursor is shorter than a perimeter of a cross-sectional shape perpendicular to a 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. 10. The manufacturing method according to claim 9, wherein in the covering step, an inner peripheral surface, both side surfaces, and at least one side of an outer peripheral surface of the belt body precursor are at least covered with a continuous outer cover fabric precursor.

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