Fabric covering set v belt and method of manufacturing the same

Abstract

The present invention relates to a wrapped fabric jointed V-belt including a plurality of wrapped fabric V-belt portions whose belt body portions are covered with a cover fabric, and a connecting belt that links the plurality of wrapped fabric V-belt portions at outer peripheral surfaces thereof, the outer peripheral surfaces of the wrapped fabric V-belt portions having a covered area covered with the cover fabric and an uncovered non-covered area, the covered area being formed in at least one side portion of the outer peripheral surface, and the cover fabric covering the covered area also covering a side surface of the wrapped fabric V-belt portion.

Description

Technical Field

[0001] This invention relates to a fabric-covered V-belt assembly formed by connecting multiple fabric-covered V-belt sections in the width direction, and a method for manufacturing the same. Background Technology

[0002] As transmission belts for transmitting power, known types include V-belts, V-ribbed belts, and flat belts, among others. V-belts include the raw-edge type (raw-edge V-belt) where the friction transmission surface (V-shaped side) is an exposed rubber layer, and the wrapped type (wrapped V-belt) where the friction transmission surface is covered by a cover fabric. These V-belts are widely used in general industrial machinery and agricultural machinery.

[0003] Furthermore, in applications such as agricultural machinery, fabric-covered V-belts are used where the entire circumference of the belt, including the friction drive surface, is covered by a cover cloth. This is because if a V-belt with exposed rubber layers is used, the coefficient of friction on the drive surface is high, increasing the stress on the belt and potentially causing premature breakage. Moreover, if straw, stones, or wood are caught in the belt, the belt and the entire transmission mechanism may be damaged by the intense impact on the drive surface. By using fabric-covered V-belts, the coefficient of friction on the drive surface is reduced, and moderate slippage alleviates the stress and impact on the belt. Additionally, it protects the drive surface from damage.

[0004] In large agricultural machinery used on large farms in Europe and America, enormous power needs to be transmitted, necessitating the simultaneous use of multiple V-belts. This means multiple V-belts are wound in parallel around the pulleys of the belt drive mechanism (multiple wrapping) and rotated. When using multiple V-belts in parallel, tension differences can arise between them, potentially disrupting stable power transmission. Furthermore, because adjacent V-belts are in contact, the inner and outer circumferences of the belts may flip, resulting in a structural inversion (belt flipping).

[0005] Therefore, when multiple V-belts are operated in parallel, a bundled belt (bundled V-belt) can be used, which consists of multiple annular V-belt sections having the same structure as V-belts connected in the belt width direction. In this bundled V-belt, multiple V-belt sections are arranged side-by-side and connected or joined using connecting straps (such as fabric bonding members). Sometimes, a fabric-covered V-belt (fabric-covered V-belt section) covered by a cover fabric is used as the V-belt section. A schematic partial cross-sectional perspective view of a typical fabric-covered bundled V-belt formed by connecting such fabric-covered V-belt sections using connecting straps (bonding members) is shown below. Figure 1 As shown.

[0006] like Figure 1As shown, the fabric-covered V-belt 100 includes two fabric-covered V-belts (fabric-covered V-belt portions) 101 arranged in parallel at intervals. The outer circumferential surfaces of the two fabric-covered V-belts 101 are connected by a connecting member (connecting strap) 102 formed of fabric. Each fabric-covered V-belt 101 is composed of an endless loop-shaped belt body (belt body portion) and a cover fabric 106 (woven fabric, knitted fabric, non-woven fabric, etc.). The endless loop-shaped belt body is formed by a tensile rubber layer 104 on the outer circumference of the belt, a compression rubber layer 103 on the inner circumference of the belt, and a core 105 embedded between the tensile rubber layer 104 and the compression rubber layer 103 along the belt length direction (circumferential direction, direction A in the figure). The cover fabric 106 covers the belt body around its entire circumferential length. In this example, the core 105 is a core wire (twisted rope) arranged at predetermined intervals in the width direction (direction B in the figure), which is in contact with the stretch rubber layer 104 and the compression rubber layer 103, and is located between the two layers.

[0007] More specifically, the fabric-covered V-belt disclosed in Japanese Patent Publication No. 47-34432 (Patent Document 1) can be cited as an example. Figure 2 A schematic partial cross-sectional view (a cross-sectional view perpendicular to the length direction of the belt) of the conventional wrapped V-belt disclosed in Patent Document 1 is shown.

[0008] exist Figure 2 In the existing wrapped V-belt 111 shown, in the belt width direction ( Figure 1 Multiple (two in the figure) fabric-covered V-belt sections V, spaced apart and arranged in parallel along the B direction, are connected by connecting straps (connecting components) T. Each fabric-covered V-belt section V consists of an endless loop-shaped main body and a cover fabric (covering fabric) 115 covering the main body. The endless loop-shaped main body is formed by stacking a compressed rubber layer 112, a core 113, and a stretched rubber layer 114 sequentially from the inner circumference to the outer circumference. The stacked structure has an inverted trapezoidal cross-section and is oriented along the length of the belt (circumference direction). Figure 1 The cover 115 extends in the direction of A. The cover 115 is formed of a seamless (one continuous piece) of fabric, covering the entire surface of the main body of the belt (the inner circumferential surface, the two side surfaces and the outer circumferential surface), and the cover 115 is overlapped on the inner circumferential side to form a double-layer structure.

[0009] However, in this existing fabric-covered V-belt 111, there is a problem that the fabric-covered V-belt portion V and the connecting belt T are easily separated. That is, since the entire body of the fabric-covered V-belt portion V is covered by the cover fabric 115, and it is bonded or connected to the connecting belt T via the cover fabric 115a covering the outer peripheral surface, it is difficult to bond or connect the fabrics with high adhesive force, especially when the connecting belt T is made of cloth.

[0010] As a countermeasure, the following attempts have been made: by exposing the rubber layer from the outer peripheral surface (back side) of the covered V-belt portion, the adhesion between the covered V-belt portion and the connecting strip is improved. For example, Japanese Patent Application Publication No. 2020-37257 (Patent Document 2) describes the following: the outer peripheral portion of the uncured rubber belt covered by the cover fabric is cut circumferentially to expose the rubber layer. In the vulcanization process, multiple uncured rubber belts with exposed rubber layers are arranged side by side, and a reinforcing fabric (connecting strip) is placed on the outer peripheral side and vulcanized. Thus, the rubber layer exposed from the uncured rubber belt is bonded to the reinforcing fabric (connecting strip) through vulcanization. Therefore, compared with the existing structure that bonds the cover fabric to the reinforcing fabric (connecting strip), the adhesion strength can be improved. In addition, Japanese Patent Application Publication No. 2022-102656 (Patent Document 3) describes the following structure: the upper part of the annular laminated structure (with main body precursor) in a semi-vulcanized state is polished with a grinding stone or sandpaper, the reinforcing cloth (cover cloth) is removed to expose the semi-vulcanized laminated structure, a connecting strip is pasted on the uneven surface of the multiple annular laminated structures after the above polishing process, and the multiple annular laminated structures in a semi-vulcanized state with the above connecting strip pasted are fully vulcanized. Existing technical documents Patent documents

[0011] Patent Document 1: Japanese Patent Publication No. 47-34432 Patent Document 2: Japanese Patent Application Publication No. 2020-37257 Patent document 3: Japanese Patent Application Publication No. 2022-102656. Summary of the Invention The problem that the invention aims to solve

[0012] Figure 3 A schematic partial cross-sectional view of the fabric-coated V-belt disclosed in Patent Documents 2-3 is shown. Figure 3 The fabric-covered V-belt 121 shown is... Figure 2 The difference in the illustrated V-belt group 111 is that the outer peripheral side of the cover fabric 125 covering the entire V-belt portion V is cut off or removed. That is, in the V-belt group 121, multiple (two in the figure) parallel V-belt portions V, spaced apart in the belt width direction, consist of a main belt body formed by sequentially layering a compressed rubber layer 122, a core 123, and a stretched rubber layer 124 from the inner peripheral side to the outer peripheral side, and two cover fabric sections 125 covering the inner peripheral surface and both sides of the main belt body. The two cover fabric sections 125 overlap on the inner peripheral side, but in the stage before being connected to the connecting belt T, such as... Figure 2Like the cover 115 of the V-belt 111 shown, the cover 125 is formed from a seamless (one continuous piece of fabric). That is, the cover 125 was originally a single continuous piece of fabric covering the entire periphery of the main body of the V-belt (including the outer periphery), but it is divided into two parts by cutting off the outer periphery of the V-belt portion V. The tensile rubber layer 124 is exposed due to the cutting off of the outer periphery, and the outer periphery surface 124a of the exposed tensile rubber layer 124 is in direct contact with the connecting belt T, so it can be bonded or connected to the connecting belt T with high adhesion through the vulcanization process.

[0013] However, the manufacturing methods disclosed in Patent Documents 2 and 3 require a step of exposing the rubber layer from the outer peripheral surface (back side) after covering the V-belt portion with a cover cloth. Patent Document 3 also requires an additional step of setting it to a semi-vulcanized state, thus complicating the process and incurring the cost disadvantage of material waste. Furthermore, since the cover cloth is completely removed from the back of the V-belt portion, there is a structural defect: on the side of the V-belt portion, the cover cloth easily spills out from the boundary between it and the connecting belt (…). Figure 3 (125a) Peeling.

[0014] Therefore, the object of the present invention is to provide a fabric-covered V-belt and a method for manufacturing the same, which can improve the adhesion between the fabric-covered V-belt portion and the connecting belt, and at the same time suppress the peeling of the cover fabric at the boundary between the side of the fabric-covered V-belt portion and the connecting belt.

[0015] Another objective of this invention is to provide a fabric-covered V-belt and a method for manufacturing the same, which can improve the adhesion between the fabric-covered V-belt portion and the connecting belt, and also improve production efficiency.

[0016] Another object of the present invention is to provide a fabric-covered V-belt and a method for manufacturing the same, which can improve the adhesion between the fabric-covered V-belt portion and the connecting belt, while also exhibiting excellent wear resistance and lateral pressure resistance.

[0017] Another object of the present invention is to provide a fabric-covered V-belt and a method for manufacturing the same, which can suppress the peeling of the fabric-covered V-belt portion from the connecting belt and has excellent durability (lifespan). means for solving problems

[0018] To achieve the aforementioned goals, the inventors conducted in-depth research and discovered that: if a covered area and an uncovered area are formed on the outer peripheral surface of the V-belt portion, and a covered area is formed by covering the side of the outer peripheral surface with a cover fabric (by folding the cover fabric inward from the side towards the outer peripheral surface), then not only can the adhesion to the connecting belt be effectively improved, but also peeling of the cover fabric at the boundary with the connecting belt can be suppressed, thus completing the present invention. In other words, the present invention can include the following solutions, etc.

[0019] Solution [1]: A fabric-covered V-belt assembly includes: a plurality of fabric-covered V-belt portions, the main body of which is covered by a cover fabric; and a connecting belt that connects the plurality of fabric-covered V-belt portions on the outer peripheral surface of each fabric-covered V-belt portion, wherein the outer peripheral surface of each fabric-covered V-belt portion has a covered area covered by the cover fabric and an uncovered area, wherein the covered area is formed on at least one side of the outer peripheral surface, and the cover fabric covering the covered area also covers the side of the fabric-covered V-belt portion.

[0020] Scheme [2]: According to Scheme [1], the wrapped V-belt is formed by extending the covered area and the uncovered area along the belt length direction.

[0021] Scheme [3]: The wrapped V-belt according to Scheme [1] or [2], wherein the covering area is formed on both sides of the outer peripheral surface.

[0022] Scheme [4]: ​​According to any one of Schemes [1] to [3], the area ratio of the non-covered area is 25% to 95% (e.g., 25% to 85%) relative to the area of ​​the outer peripheral surface of the covered V-belt portion.

[0023] Scheme [5]: A V-belt with a fabric covering according to any one of Schemes [1] to [4], wherein the main body of the belt is covered by 1 to 3 layers of cover fabric.

[0024] Scheme [6]: A V-belt with a fabric covering according to any one of Schemes [1] to [5], wherein the main body of the belt is covered by multiple layers of fabric.

[0025] Scheme [7]: The wrapped V-belt according to any one of Schemes [1] to [6], wherein the main body of the belt is covered by multiple layers of cover fabric, wherein the outermost first cover fabric of the multiple layers of cover fabric forms the covering area (covering a part of the outer peripheral surface) on the outer peripheral surface, and one or more second cover fabrics located on the inner side of the first cover fabric do not cover the outer peripheral surface (do not form the covering area).

[0026] Scheme [8]: A fabric-covered V-belt according to any one of Schemes [1] to [7], wherein the connecting belt comprises at least fibers.

[0027] Solution [9]: A method for manufacturing a fabric-covered V-belt, which is the method for manufacturing a fabric-covered V-belt according to any one of Solutions [1] to [8], includes at least: a covering step, in which a cover fabric precursor is used to cover a belt main body precursor to form a fabric-covered V-belt precursor; and a connecting step, in which the outer peripheral surfaces of multiple fabric-covered V-belt precursors obtained in the covering step are connected by a connecting belt precursor, wherein in the covering step, the inner peripheral surface and both sides of the belt main body precursor are covered, and at the same time, the cover fabric precursor covering the side is used to cover at least one side of the outer peripheral surface and not cover a part of the outer peripheral surface.

[0028] Solution

[10] : The manufacturing method according to Solution [9] does not include the process of removing or cutting off the outer peripheral surface of the cover fabric precursor obtained in the covering process.

[0029] Solution

[11] : According to the manufacturing method described in Solution [9] or

[10] , in the covering process, the width of the cover fabric precursor is smaller than the perimeter of the cross-sectional shape of the main body of the belt precursor perpendicular to the length direction, and the width direction of the cover fabric precursor is covered in a direction perpendicular to the length direction of the belt.

[0030] Scheme

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

[11] , wherein, in the covering process, at least one side of the inner peripheral surface, both sides and the outer peripheral surface of the main body of the fabric is covered with a seamless (one continuous piece) cover fabric precursor. Invention Effects

[0031] In this invention, a covered area and an uncovered area are formed on the outer peripheral surface of the wrapped V-belt portion. The covered area is formed by covering at least one side of the outer peripheral surface with a cover fabric that covers the side of the wrapped V-belt portion (by folding it inwards from the side towards the outer peripheral surface). Therefore, the adhesion between the wrapped V-belt portion and the connecting belt is effectively improved, and peeling of the cover fabric at the boundary between the side of the wrapped V-belt portion and the connecting belt is effectively suppressed. Furthermore, the improved adhesion and increased production efficiency (or reduced defect rate) can be achieved simultaneously. In addition, improved wear resistance and lateral pressure resistance are also achieved. Furthermore, the peeling between the wrapped V-belt portion and the connecting belt is suppressed, providing a wrapped V-belt with excellent durability (lifespan). Attached Figure Description

[0032] Figure 1 This is a schematic partial cross-sectional perspective view showing an example of an existing fabric-coated V-belt. Figure 2 This is a schematic partial cross-sectional view showing another example of an existing fabric-coated V-belt. Figure 3This is a schematic partial cross-sectional view showing another example of an existing wrapped V-belt. Figure 4 This is a schematic partial cross-sectional view illustrating an example of the wrapped V-belt of the present invention. Figure 5 This is a schematic partial cross-sectional view illustrating another example of the wrapped V-belt of the present invention. Figure 6 This is a schematic partial cross-sectional view illustrating yet another example of the wrapped V-belt of the present invention. Figure 7 This is a schematic partial cross-sectional view showing yet another example of the wrapped V-belt of the present invention. Figure 8 This is a graph showing the relationship between the proportion of the uncovered area of ​​the wrapped V-belt obtained in the embodiments, reference examples and comparative examples and the peel force of the connecting belt. Figure 9 This is a schematic diagram showing the layout of a biaxial running test machine used to evaluate the abrasion resistance (wear rate) of the fabric-coated V-belts obtained in the embodiments and reference examples. Figure 10 This is a schematic diagram showing the layout of a triaxial running test machine used to evaluate the durability of the wrapped V-belts obtained in the embodiments and reference examples. Detailed Implementation

[0033] The invention will now be described in detail with reference to the accompanying drawings. Furthermore, in the following description, the same reference numerals are sometimes used to denote the same or functionally common elements (or components).

[0034] The fabric-covered V-belt of the present invention includes: a plurality of fabric-covered V-belt portions whose main body is covered by a cover fabric, and a connecting belt connecting the fabric-covered V-belt portions on their outer peripheral surfaces. The outer peripheral surfaces of the fabric-covered V-belt portions have covered areas and uncovered areas. As an example of the fabric-covered V-belt of the present invention... Figure 4 A rough partial sectional view is shown.

[0035] Figure 4 In the shown fabric-covered V-belt group 1, with Figures 1-3 The difference between the existing fabric-covered V-belt shown is that the outer periphery of the fabric-covered V-belt portion V (or belt body portion) has a covered area 5a covered by the cover fabric 5 and an uncovered area (the part of the stretch rubber layer 4 exposed) 4a.

[0036] That is, in the wrapped V-belt 1, multiple wrapped V-belt sections V (two in the figure) arranged parallel to each other at intervals in the belt width direction are composed of a belt body and a cover fabric 5 covering the belt body. The belt body is formed by sequentially stacking a compression rubber layer 2, a core (core layer or core wire) 3, and a stretch rubber layer 4 from the inner peripheral side to the outer peripheral side (back side). The cover fabric 5 covers the inner peripheral surface, both sides, and a part of the outer peripheral surface of the belt, thereby forming the covered area 5a and the uncovered area (exposed part of the stretch rubber layer 4) 4a on the outer peripheral side of the wrapped V-belt section V.

[0037] Furthermore, the covered area 5a and the uncovered area (exposed portion of the stretch rubber layer 4) 4a are formed extending along the length of the belt, and like other elements (compression rubber layer 2, core 3, stretch rubber layer 4, cover fabric 5 and connecting strip (bonding member) T), they are preferably formed along the entire length or circumference of the belt.

[0038] In the wrapped V-belt 1, the exposed portion (exposed surface) of the tensile rubber layer 4 exposed in the non-covered area 4a can directly contact the connecting belt T. Therefore, it can utilize the cross-linking during the formation of the tensile rubber layer 4 to bond or connect with the connecting belt T with high adhesion.

[0039] Furthermore, the non-covered area (exposed portion of the stretch rubber layer 4) 4a is formed in the center or interior of the outer peripheral surface of the belt (the area on the outer peripheral surface, away from the two ends in the belt width direction), and the covered area 5a is formed on both sides of the outer peripheral surface of the belt (the area on the outer peripheral surface, near the two ends in the belt width direction). In this example, the cover fabric 5 is formed of seamless (continuous) fabric, so the inner peripheral surface, both sides, and a portion of the outer peripheral surface (the covered areas 5a on both sides of the outer peripheral surface) are seamlessly (continuously) covered. Therefore, the ends of the cover fabric 5 covering the inner peripheral surface and both sides of the belt are folded (or buried) between the belt body and the connecting belt T as covered areas 5a. Thus, in the form where the ends of the cover fabric 5 are folded (or buried) (i.e., the cover fabric 5 covering the covered areas 5a also covers the sides of the wrapped fabric V-belt portion V), the ends of the cover fabric 5 do not contact the pulleys, etc., and therefore... Figure 3 Unlike the existing fabric-covered V-belt 121 shown, this one can effectively suppress the peeling of the cover fabric 5 at the boundary between the side of the fabric-covered V-belt portion V and the connecting belt T.

[0040] Furthermore, as shown in this example, if the cover fabric is formed of seamless (continuous) fabric in the circumferential direction of the cross section (the cross section perpendicular to the length direction of the belt), then in the covering process described later in the manufacturing method, it is possible to continuously cover along the length direction of the belt with a single continuous cover fabric precursor (fabric), thus effectively improving production efficiency.

[0041] Additionally, in this example, as the cover fabric 5, a seamless (one continuous piece) of fabric is used in the circumferential direction of the cross-section (the cross-section perpendicular to the length direction of the fabric). However, fabrics formed by joining (connecting) the ends of two or more pieces of fabric or by partially overlapping and joining them together can also be used. For example, it can be... Figure 4 The cover 5 is designed so that two pieces of fabric overlap on the inner circumference or one side of the band (e.g., as shown in the image). Figure 3 The existing V-belt 121 shown has a cover fabric 125 that overlaps on the inner circumferential surface of the belt to form a joining configuration. Alternatively, one fabric can continuously cover the inner circumferential surface, one side, and one covered area of ​​the belt, while another fabric joined to this fabric at the inner circumferential surface covers the inner circumferential surface, another side, and another covered area. In this configuration, even without forming a main body portion with a reinforcing fabric layer or the like on the inner circumferential surface side of the compression rubber layer, the inner circumferential surface side of the belt can be effectively reinforced.

[0042] Figure 5 A schematic partial cross-sectional view of another example of the wrapped V-belt of the present invention is shown. Figure 5 In the shown fabric-covered V-belt 11, with Figure 4 The difference in the illustrated fabric-covered V-belt 1 is that a covered area 15a is formed on one side of the outer peripheral surface, while no covered area is formed on the other side (the remaining portion other than the covered area 15a formed only on one side of the outer peripheral surface is designated as the non-covered area 14a). Therefore, the compression rubber layer 12 and core 13 are the same as the compression rubber layer 2 and core 3 of the aforementioned fabric-covered V-belt 1, and the stretch rubber layer 14 and cover fabric 15 are the same as the stretch rubber layer 4 and cover fabric 5, except that their shapes correspond to the non-covered area 14a and the covered area 15a. In this configuration, the large area of ​​the non-covered area 14a allows for more effective improvement in adhesive strength.

[0043] Furthermore, when a covering area is formed on one side, it is preferable that the covering area is formed at least on the outermost side of the wrapped V-belt in the belt width direction [i.e., the outermost (both ends) of the wrapped V-belt portion in the belt width direction, on the outer peripheral side of the belt width direction]. For example, in the case of a wrapped V-belt with two wrapped V-belt portions, it is preferable that... Figure 5 The positional relationship shown forms a covering area at least at both ends in the belt width direction. This arrangement effectively suppresses the peeling of the cover fabric. Specifically, when used with an idler pulley, tensioner, etc., on the back side (connecting belt side) of the wrapped V-belt, the frequency of contact between the two ends in the belt width direction and the flanges of these pulleys [restrictive portions or walls formed on both sides of the pulleys in the thickness direction (axial direction) to prevent belt slippage] tends to increase. Therefore, the cover fabric tends to peel more easily at the outermost edge in the belt width direction, but by forming a covering area at the outermost edge (both ends) in the belt width direction, peeling of the cover fabric can be effectively suppressed.

[0044] Figure 6 A schematic partial cross-sectional view showing another example of the wrapped V-belt of the present invention is shown. Figure 6 The fabric-covered V-belt 21 shown is... Figure 4 The difference between the fabric-covered V-belt 1 shown is that the cover fabric is set to two layers, while the rest of the structure (compression rubber layer 22, core 23, etc.) is the same as that of the fabric-covered V-belt 1. Figure 6 In the V-belt 21 with fabric covering, the main body of the belt is surrounded by a first cover (outer cover) 25 located on the outer side and a second cover (inner cover) 26 located on the inner side (belt main body side) of the first cover. The inner second cover 26 and... Figure 4 Similarly, the cover fabric 5 in the V-belt 1 is formed of seamless (continuous) fabric, seamlessly (in a continuous form) covering the inner circumferential surface, both sides, and a portion of the outer circumferential surface (covered areas on both sides of the outer circumferential surface) 26a. Along this second cover fabric 26, a first cover fabric 25, also formed of seamless (continuous) fabric, similarly covers the outer side of the belt (outside of the second cover fabric 26), forming covered areas 25a on both sides of the outer circumferential surface of the belt. In this multi-layered cover fabric configuration, even with wear development on the side cover fabric of the V-belt section, the rubber of the belt body can be effectively prevented from being exposed.

[0045] In addition, this example also involves Figure 4 Similarly, in the V-belt 1 with its fabric-covered interlocking structure, the non-covered area 24a [the exposed portion (exposed surface) of the tensile rubber layer 24] can directly contact the connecting belt T, thus enabling it to bond or connect with the connecting belt T with high adhesion through cross-linking. Furthermore, since the cover fabrics 25 and 26 covering the covered areas 25a and 26a also cover the sides of the belt (i.e., the ends of the cover fabrics 25 and 26 are folded in or embedded at the boundary with the connecting belt T), peeling from the ends of the cover fabrics 25 and 26 at the boundary can be effectively suppressed. Moreover, in the covering process described later in the manufacturing method section, production efficiency can be effectively improved.

[0046] Furthermore, in this example, the two cover sheets 25 and 26 cover the same area on the outer periphery of the main body of the belt. However, when the cover sheets are multi-layered, multiple cover sheets can also cover the same or different areas to form a covered area. For example, it can be in the following form: each covered area 25a of the first cover sheet (outer cover sheet) 25 extends to the center side of the outer periphery than each covered area 26a of the second cover sheet (inner cover sheet) 26 [a form in which the covered areas 25a (overlapping with 26a), covered areas 25a (single layer), non-covered areas 24a, covered areas 25a (single layer), and covered areas 25a (overlapping with 26a) are arranged in the order of one side of the outer periphery towards the other side]. It can also be in the following configuration: on one side, the covering area 25a extends to a position closer to the center of the outer peripheral surface than the covering area 26a; on the other side, the covering area 26a extends to a position closer to the center of the outer peripheral surface than the covering area 25a [arranged from one side of the outer peripheral surface to the other side in the following order: covering area 25a (overlapping with 26a), covering area 25a (single layer), non-covering area 24a, covering area 26a (single layer), covering area 25a (overlapping with 26a)]. Furthermore, in multi-layered covers, not all covers may necessarily form covering areas.

[0047] For example, Figure 7 A schematic partial cross-sectional view of another example of the wrapped V-belt of the present invention is shown. Figure 7 The fabric-covered V-belt 31 shown is... Figure 6 The difference in the illustrated fabric-covered V-belt 21 is that the second cover fabric (inner cover fabric) 36 located on the inner side does not cover the outer circumference of the belt (does not form a covered area), while the remaining structure (compression rubber layer 32, core 33, etc.) is the same as the aforementioned fabric-covered V-belt 21 (or 1). That is, in Figure 7 In the V-belt 31 with its covering fabric, the second cover fabric (inner cover fabric) 36 located on the inner side does not form a covering area on the outer peripheral surface; it uses seamless (continuous) fabric to cover only the inner peripheral surface and both sides of the belt. The first cover fabric (outer cover fabric) located on the outer side covers the inner peripheral surface and both sides of the belt with seamless (continuous) fabric, and also covers both sides of the outer peripheral surface to form a covering area 35a (the two ends of the fabric are folded in or buried at the boundary with the connecting belt T). In this manner, with... Figure 6 Similarly, with the V-belt 21 with its fabric-covered joints, even as wear develops on the side cover of the V-belt section, not only can multiple layers of cover effectively prevent the rubber of the belt body from being exposed, but the covered area is formed by a single layer of cover, thus effectively suppressing the decrease in belt flexibility. Furthermore, the material cost of the cover can be reduced, which is also cost-effective.

[0048] In addition, if the belt has good flexibility (can be bent with a small force), the stress generated by bending is small, so it is less likely to crack and thus tends to improve durability. At the same time, because the energy consumed by bending (heat loss) is reduced, it also tends to improve transmission efficiency.

[0049] Furthermore, in this example, it is also related to Figure 6 (or Figure 4 Similarly, the uncovered area 34a [the exposed portion (exposed surface) of the stretched rubber layer 34] of the V-belt 21 (or 1) can directly contact the connecting belt T, thus enabling it to bond or connect with the connecting belt T with high adhesion through cross-linking. Furthermore, the first cover fabric (outer cover fabric) 35 covering the covered area 35a also covers the side of the belt (i.e., the end of the outer cover fabric 35 is folded in or embedded at the boundary with the connecting belt T), thus effectively suppressing peeling from the end of the cover fabric at the boundary even if the end of the second cover fabric (inner cover fabric) 36 is not folded in. Moreover, in the covering process described later in the manufacturing method section, production efficiency can be effectively improved.

[0050] in addition, Figure 7 The cover fabric consists of two layers: an outermost first cover fabric (outer cover fabric) 35 and an innermost second cover fabric (inner cover fabric) 36. However, it does not necessarily need to be two layers; the inner second cover fabric can also be stacked in multiple layers. When the inner second cover fabric is multi-layered, at least one layer of the second cover fabric can form a covering area on the outer peripheral side of the belt. However, from the perspective of improving the flexibility of the belt and reducing material costs, preferably, not all of the multiple second cover fabrics (inner cover fabrics) form a covering area, but only the outermost first cover fabric (outer cover fabric) forms a covering area. Therefore, preferably, one or more second cover fabrics (inner cover fabrics) do not cover the outer peripheral surface of the belt, but cover at least a portion of the area selected from the inner peripheral surface and both sides of the belt (preferably the inner peripheral surface and both sides of the belt).

[0051] [Cover] The cover fabric is made of conventional fabric. Examples of fabrics include woven fabrics, knitted fabrics (weft-knitted fabrics, warp-knitted fabrics), and non-woven fabrics. Among these, woven fabrics woven in plain weave, twill weave, or satin weave, woven fabrics with a large angle between the warp and weft yarns (greater than 90° and less than 120°), and knitted fabrics are preferred. Woven fabrics commonly used as cover fabrics for drive belts in general industrial and agricultural machinery [plain weave fabrics with right-angled warp and weft yarns, plain weave fabrics with a large angle between the warp and weft yarns (wide-angle canvas)] are particularly preferred. Furthermore, wide-angle canvas can also be used for applications requiring durability.

[0052] In addition, from the perspective of flexibility, the cover fabric is preferably configured such that the extension directions of the warp and weft yarns are intersecting the direction of the belt length; it can also be configured such that the directions of the warp and weft yarns are respectively 45° to 75° (e.g., 50° to 70°) relative to the direction of the belt length, preferably 55° to 65°.

[0053] The fibers used to make up fabrics can be: polyolefin fibers (polyethylene fibers, polypropylene fibers, etc.), polyamide fibers (polyamide 6 fibers, polyamide 66 fibers, polyamide 46 fibers, aromatic polyamide fibers, etc.), polyester fibers (polyalkylene arylate fibers, etc.), vinylon fibers (polyvinyl alcohol fibers, ethylene-vinyl alcohol copolymer fibers, vinylon fibers, etc.), poly(p-phenylenebenzobisoxazole) (PBO) fibers, and other synthetic fibers; cellulose fibers (cellulose fibers or cotton, cellulose derivative fibers, etc.), natural fibers such as hemp and wool; and inorganic fibers such as carbon fiber. These fibers can be used alone as single yarns or as blends of two or more types of yarns.

[0054] Among these fibers, blended yarns of polyester and cellulose fibers are preferred from the perspective of superior mechanical properties and economic efficiency.

[0055] Polyester fibers can be polyalkylene aryl fibers. Examples of polyalkylene aryl fibers include: polyethylene terephthalate (PET) fiber, polyethylene naphthalate (PEN) fiber, etc. 2-4 Alkylene-C 8-14 Aromatic ester fibers, etc.

[0056] Cellulose fibers include cellulose fibers (cellulose fibers derived from plants, animals, or bacteria) and cellulose derivative fibers. Examples of cellulose fibers include: wood pulp (coniferous and broadleaf pulp, etc.), bamboo fiber, sugarcane fiber, seed hair fiber (cotton fiber (cotton linters), kapok, etc.), bast fiber (hemp, paper mulberry, daphne, etc.), leaf fiber (Manila hemp, New Zealand hemp, etc.) and other naturally plant-derived cellulose fibers (pulp fibers); animal-derived cellulose fibers such as sea squirt cellulose; bacterial cellulose fibers; algal cellulose, etc. Examples of cellulose derivative fibers include: cellulose ester fibers, regenerated cellulose fibers (rayon, cuprammonium cellulose, lyocell fiber, etc.).

[0057] The mass ratio of polyester fiber to cellulose fiber is, for example, 90 / 10 to 10 / 90, preferably 80 / 20 to 20 / 80, and more preferably around 70 / 30 to 30 / 70 (especially around 60 / 40 to 40 / 60).

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

[0059] The weight per unit area of ​​the fabric (raw fabric) is, for example, 100–500 g / m². 2 Preferably, it is 200–400 g / m 2 More preferably 250–300 g / m 2 about.

[0060] When the fabric (raw fabric) is woven fabric, the yarn density (warp density, weft density) of the fabric is, for example, 60-100 yarns / 50mm, preferably 65-90 yarns / 50mm, and more preferably around 70-80 yarns / 50mm.

[0061] To improve adhesion to the main body of the fabric, the cover cloth can undergo conventional adhesive treatment (or surface treatment) [e.g., treatment based on a treatment liquid containing adhesive components]. Examples of adhesive components (or surface treatment agents) used in adhesive treatment include: isocyanates (polyisocyanate compounds), epoxy resins (epoxy compounds), silane coupling agents, amino resins, rubber components (rubber latex or rubber paste, etc.), and RFL solutions containing resorcinol (R), formaldehyde (F), and rubber or latex (L) [e.g., RFL solutions containing resorcinol (R) and formaldehyde (F) forming a condensate (RF condensate) and containing rubber components such as vinylpyridine-styrene-butadiene copolymer rubber]. These can be used alone or in combination of two or more; treatment can also be performed sequentially multiple times using the same or different adhesive components.

[0062] Among these adhesive components, rubber components, RFL liquid, or combinations thereof are preferred. Furthermore, the rubber component preferably contains an adhesive component of the same type (preferably identical) rubber component as the rubber component of the main body (stretch rubber layer, compression rubber layer, etc.).

[0063] Bonding treatments based on rubber components can include, for example, soaking (impregnating) the fabric in a rubber paste containing a rubber composition with rubber components dissolved in a solvent, or wiping (applying) a solid portion of the aforementioned rubber composition onto the fabric. The bonding treatment only requires treating at least one surface of the fabric, preferably at least the surface (especially both sides) in contact with the main body of the fabric.

[0064] As a rubber component constituting the rubber composition (rubber composition for bonding treatment) attached to the cover fabric, examples include rubber components that are the same as those exemplified in the section on stretched rubber layers described later, including those in preferred manner. The rubber component in the rubber composition for bonding treatment is preferably the same (especially identical) rubber component as the rubber component in the crosslinked rubber composition forming the stretched rubber layer and / or the compressed rubber layer.

[0065] In addition to the aforementioned rubber components, the rubber composition used for bonding may contain conventional additives as needed, or it may not contain any. Examples of additives include those exemplified in the section on tensile rubber layers described later, including those in preferred embodiments.

[0066] The weight per unit area of ​​the bonded fabric (treated fabric) is, for example, 300–800 g / m². 2 Preferably, it is 400–600 g / m 2 More preferably 450–550 g / m 2 about.

[0067] The average thickness of the cover (or the average thickness of each layer in the case of multiple layers) is, for example, 0.4 to 2 mm, preferably 0.45 to 1.4 mm, and more preferably about 0.5 to 1 mm (e.g., 0.55 to 0.8 mm). If the cover is too thin, its abrasion resistance may decrease; if it is too thick, its flexibility may decrease.

[0068] The coefficient of friction of the cover fabric serving as the transmission surface is, for example, 0.9 to 1, preferably 0.91 to 0.96, and more preferably around 0.92 to 0.95. Furthermore, in this specification and claims, the coefficient of friction can be measured according to the method described in Japanese Patent Application Publication No. 2022-85864.

[0069] The cover fabric can be a single layer formed by a single piece of cover fabric, as long as it can form a covered area and a non-covered area on the outer periphery of the belt. From the perspective of easily improving wear resistance, it can also be a multi-layer or multiple-layered cover fabric (e.g., 2 to 5 layers, preferably 2 to 4 layers, further preferably about 2 to 3 layers, especially 2 layers). However, from the perspective of production efficiency and lateral pressure resistance, 1 to 3 layers [e.g., a single layer (1 layer) or two layers (double layer)] are preferred. From the perspective of good balance and excellent durability of production efficiency, wear resistance and lateral pressure resistance, 2 to 3 layers are further preferred, and 2 layers are particularly preferred. If there are too many layers of cover fabric, production efficiency may decrease, and the resistance to lateral pressure may also decrease (and consequently, durability will also decrease). If there are too few layers, when manufacturing based on the manufacturing method described later, it is easy for parts of the belt side (drive surface) not to be covered by the cover fabric during the covering process (rubber may easily be exposed from the side). Not only may production efficiency and wear resistance decrease, but also rubber may easily seep out or be exposed from the worn cover fabric during belt operation. Due to the increased friction coefficient and heat generation between the belt and pulley (heat generation will reduce the adhesion between the covered V-belt and the connecting belt), durability may decrease.

[0070] When the cover is multi-layered (a form formed by stacking multiple cover sheets), each cover sheet can cover the same or different areas on the outer periphery of the main body of the belt, thus forming a covered area. Furthermore, in multi-layered cover sheets, not all cover sheets need to form a covered area; at least one cover sheet is sufficient. For example, the first cover sheet located on the outermost side (belt wheel side) at least covers the outer periphery of the belt (forming a covered area); one or more second cover sheets located on the inner side (belt main body side) of the belt, located closer to the first cover sheet (outer cover sheet), can also cover the outer periphery, but from the perspective of belt flexibility and material cost reduction, it is preferable not to cover the outer periphery (not forming a covered area).

[0071] The cover fabric, which at least covers the inner circumference and both sides of the belt, is typically formed extending along the length of the belt. On the outer circumference of the belt, the covered area and the uncovered area, which are at least covered by the cover fabric, may not necessarily extend along the length of the belt, but from a production efficiency perspective, it is preferable to form them extending along the length of the belt. The fabric forming the cover fabric (or each layer of fabric when the cover fabric is multi-layered) is preferably a seamless (one continuous piece) fabric in the circumferential direction and / or the length direction of the belt cross-section (the cross-section perpendicular to the belt length direction). That is, the fabric forming the cover fabric is preferably a single continuous piece of fabric capable of covering at least the inner circumference and both sides of the belt along its entire length [preferably further covering at least one side (especially both sides) of the outer circumference] of the belt.

[0072] In addition, in this application, seamless or continuous fabric (covering cloth or covering cloth precursor) refers to a piece of fabric that can be rolled up independently in the state before the covering process (or covering cloth precursor), and may also have a joint (connecting part), etc., such as fabric formed by joining (connecting) the ends of two or more pieces of fabric or partially overlapping them.

[0073] The covering area is preferably formed on at least one side of the outer periphery of the belt in a cross section perpendicular to the belt length direction (both sides are preferred for better simultaneous adhesion to the connecting belt and production efficiency); if the cover cloth covering the covering area (the side of the outer periphery of the belt) also covers the side of the belt, that is, the end of the cover cloth covering the side of the belt is folded in or buried at the boundary with the connecting belt, it is preferred in that the end of the cover cloth can be effectively prevented from peeling off from the boundary.

[0074] The area of ​​the outer periphery of the V-belt portion (the cross-linked V-belt portion) relative to the total area of ​​the covered and uncovered areas can be, for example, about 1% to 99% (e.g., 15% to 97%, preferably 25% to 95%), or about 10% to 90% (e.g., 20% to 90%), more preferably 25% to 85% (e.g., 26% to 83%), and even more preferably about 30% to 80% (e.g., 40% to 70%). However, from the perspective of excellent balance between adhesion to the connecting belt, abrasion resistance (especially easy suppression of peeling of the cover fabric at the boundary with the connecting belt), and production efficiency (especially the workability and yield of the covering process), it can be, particularly preferably, 50% to 90% (e.g., 55% to 85%, preferably 60% to 80%, and even more preferably 65% ​​to 75%). The above-mentioned area ratio can also be the area ratio in the form of a single layer (one layer) or multiple layers (especially a single layer) of cover fabric. Furthermore, when the cover fabric is multi-layered (e.g., 2 to 4 layers, preferably 2 to 3 layers, particularly 2 layers), the area ratio of the non-covered area relative to the area of ​​the outer periphery of the V-belt portion of the cover fabric can be, for example, about 20% to 98% (e.g., 25% to 95%), preferably 30% to 97% (e.g., 40% to 95%), more preferably 45% to 96% (e.g., 50% to 95%, preferably 55% to 85%, and more preferably 60% to 80%), and even more preferably 60% to 95% (e.g., 20% to 98%). The percentage of non-covered area is approximately 65%–93%, preferably 65%–75%, with an even higher percentage of approximately 68%–92% (e.g., 70%–90%). From the perspective of achieving a superior balance between adhesion to the connecting belt, abrasion resistance (especially ease of suppressing peeling of the cover at the boundary with the connecting belt), and production efficiency (especially the workability and yield of the covering process), approximately 50%–90% (e.g., 55%–85%, preferably 60%–80%, further preferably 65%–75%) is particularly preferred. If the proportion of the non-covered area is too small, it may not be possible to adequately ensure adhesion (or peel force) to the connecting belt; if the proportion of the non-covered area is too large, for example, when manufactured using the method described later, it may be difficult to align the cover with the belt body during the covering process, potentially resulting in uncovered areas on the belt side (drive surface) (reduced production efficiency). Furthermore, in cloth-covered V-belts, if the rubber is exposed on the belt side (drive surface), the coefficient of friction on the belt side may locally increase, resulting in uneven circumferential characteristics or properties. This significantly reduces wear resistance and noise reduction, sometimes rendering the belt unsuitable for cloth-covered V-belt applications. However, when the cover is multi-layered, even if the proportion of uncovered areas is relatively large, the tendency for uncovered areas to appear (leading to decreased production efficiency) can be effectively suppressed.

[0075] In addition, in this application, the area ratio of the non-covered area can be determined according to the method described in the embodiments below.

[0076] [With main body] The main body of the belt is covered with a cover fabric, which covers the inner circumferential surface, both sides, and a portion of the outer circumferential surface, forming a covered V-belt section. For example, the covered V-belt section can consist of an endless loop belt body (belt main body) with a V-shaped cross-section and the cover fabric, with the left and right sides of the V-shaped cross-section covered by the cover fabric serving as friction drive surfaces. The belt body has a compression rubber layer on the inner circumferential side, a tension rubber layer on the outer circumferential side, and a core layer (adhesive rubber layer) with embedded core wires between them. The cover fabric covers the entire length of the belt along the circumferential direction of the belt body, around the V-shaped cross-section. Furthermore, in the V-shaped cross-section, the side with a wider bandwidth is designated as the outer circumferential side, and the side with a narrower bandwidth is designated as the inner circumferential side. Additionally, a reinforcing fabric layer formed along the belt length direction on the inner circumferential side of the compression rubber layer can be included as needed.

[0077] The outer peripheral surface (surface of the stretch rubber layer) of the V-belt (belt body) has an uncovered area that is not covered by the cover cloth, thus exposing the stretch rubber layer; the exposed stretch rubber layer can be firmly bonded or combined with the connecting belt during cross-linking (the bonding process in the manufacturing method described later), thus ensuring sufficient adhesion (peel force).

[0078] [Stretch rubber layer] The stretch rubber layer can be formed from a vulcanized or cross-linked rubber composition commonly used as a rubber composition (including rubber compositions of rubber components) for wrapping V-belts.

[0079] rubber components As the rubber component in the crosslinked rubber composition forming the stretched rubber layer, it 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, nitrile rubber (nitrile rubber); hydrogenated nitrile rubber (including hydrogenated nitrile rubber and unsaturated carboxylic acid metal salts, etc., and hydrides of the above diene rubbers], olefin rubbers [e.g., ethylene-α-olefin rubbers (ethylene-α-olefin elastomers), polyoctene rubber, ethylene-vinyl acetate copolymer rubber, chlorosulfonated polyethylene rubber, alkylated chlorosulfonated polyethylene rubber, etc.], epichlorohydrin rubber, acrylic rubbers, silicone rubber, polyurethane rubber, fluororubber, etc. These rubber components can be used alone or in combination of two or more.

[0080] Among these, ethylene-alpha-olefin elastomers (ethylene-alpha-olefin rubbers) such as ethylene-propylene copolymer (EPM) and ethylene-propylene-diene terpolymer (EPDM), as well as chloroprene rubber, are widely used, considering the ease of diffusion of crosslinking agents (or vulcanizing agents) and crosslinking accelerators (or vulcanization accelerators). Especially in high-load environments such as gear belts, chloroprene rubber and EPDM are preferred due to their excellent balance of mechanical strength, weather resistance, heat resistance, cold resistance, oil resistance, and adhesion. Chloroprene rubber can be sulfur-modified or non-sulfur-modified. Furthermore, ethylene-alpha-olefin elastomers such as EPDM are particularly preferred because they offer superior heat resistance and weather resistance compared to chloroprene rubber, and can be filled with reinforcing agents to easily improve mechanical strength. EPDM and other ethylene-α-olefin elastomers tend to have lower adhesion than neoprene rubber and are prone to peeling off from the connecting strip. However, in the wrapped V-belt of the present invention, even if EPDM and other ethylene-α-olefin elastomers are used as the rubber component of the stretching rubber layer, they can still adhere to the connecting strip with high adhesion and effectively suppress peeling off of the connecting strip.

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

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

[0083] In addition, in this application, the ethylene content refers to the mass ratio of ethylene units in the total units constituting the ethylene-α-olefin elastomer, which can be determined by conventional methods, but can also be based on the proportion of ethylene as a monomer.

[0084] Furthermore, in this application, when there are multiple ethylene-α-olefin elastomers, the ethylene content refers to the 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 content of each ethylene-α-olefin elastomer and its mass fraction.

[0085] In ethylene-α-olefin elastomers, the ratio (mass ratio) of ethylene to α-olefin can be 40 / 60 to 90 / 10, preferably 45 / 55 to 80 / 20, more preferably 50 / 50 to 70 / 30, and even more preferably around 50 / 50 to 60 / 40.

[0086] The diene content (particularly the ethylene norbornene content) of ethylene-α-olefin elastomers (especially ethylene-α-olefin-diene terpolymers such as EPDM) is, for example, 0.1–15% by mass, preferably 1–10% by mass, more preferably 2–8% by mass, more preferably 3–7% by mass, and most preferably about 4–6% by mass. If the diene content is too high, high heat resistance may not be guaranteed. If the diene content is too low, processability and crack resistance may decrease.

[0087] In addition, in this application, diene content refers to the mass ratio of diene monomer units in the total units constituting the ethylene-α-olefin elastomer, which can be determined by conventional methods or based on the proportion of monomers.

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

[0089] In addition, in this application, the Mooney viscosity [ML(1+4) 125°C] can be determined according to the method of JIS K 6300-1 (2013), with the following test conditions: using an L-shaped rotor, test temperature 125°C, preheating for 1 minute, and rotor operating time for 4 minutes. Mooney viscosity is measured by filling the chamber with uncrosslinked ethylene-α-olefin elastomer in contact with a grooved roller, and measuring the torque required to rotate the rotor; thus, it is used as an indicator of rubber flowability (processing difficulty).

[0090] Furthermore, in this application, when there are multiple ethylene-α-olefin elastomers, the Mooney viscosity refers to the average value based on the mass ratio (average Mooney viscosity). That is, the average Mooney viscosity is the sum of the products of the Mooney viscosity of each ethylene-α-olefin elastomer and its mass fraction.

[0091] additive In addition to the aforementioned rubber components, the aforementioned crosslinked (vulcanized) rubber composition may contain conventional additives as needed, or may not contain them. Examples of additives include: fillers, short fibers, crosslinking agents (or vulcanizing agents), co-crosslinking agents or crosslinking aids (or vulcanization aids), crosslinking accelerators (or vulcanization accelerators), crosslinking delay agents (or vulcanization delay agents), metal oxides (calcium oxide, barium oxide, iron oxide, copper oxide, titanium dioxide, aluminum oxide, zinc oxide, etc.), softeners (paraffinic oils, naphthenic oils, etc.), processing agents or processing aids (e.g., fatty acids such as stearic acid, fatty acid metal salts such as stearic acid metal salts, fatty acid amides such as stearamide, waxes, paraffin, etc.), plasticizers [aliphatic carboxylic acid plasticizers (adipate ester plasticizers, sebacic acid ester plasticizers, etc.), aromatic carboxylic acid ester plasticizers (phthalate plasticizers, trimellitate plasticizers, etc.), oxycarboxylic acid ester plasticizers, phosphate esters]. Plasticizers, ether plasticizers, ether ester plasticizers, etc.; adhesive modifiers [e.g., resorcinol-formaldehyde cocondensates (RF condensates), amino resins (condensates of nitrogen-containing cyclic compounds and formaldehyde, such as melamine resins like hexamethylol melamine, hexaalkoxymethyl melamine (hexamethoxymethyl melamine, hexabutoxymethyl melamine, etc.), urea-formaldehyde resins like hydroxymethyl urea, benzoguanamine resins like hydroxymethyl benzoguanamine resins, etc.), their cocondensates (resorcinol-melamine-formaldehyde cocondensates, etc.), etc.]; tackifiers; coupling agents (silane coupling agents, etc.); anti-aging agents (antioxidants, heat aging agents, flexural cracking agents, ozone deterioration agents, etc.); stabilizers (UV absorbers, heat stabilizers, etc.); flame retardants; colorants; lubricants; antistatic agents, etc. Additionally, metal oxides can act as crosslinking agents depending on the type of rubber components. In addition, in the adhesive modifier, resorcinol-formaldehyde cocondensate and amino resin can be the initial condensate (prepolymer) of nitrogen-containing cyclic compounds such as resorcinol and / or melamine with formaldehyde.

[0092] Examples of fillers mentioned above include carbon black, silica, clay, calcium carbonate, talc, and mica. Most fillers include reinforcing fillers, such as carbon black and silica (reinforced silica). Generally, silica has lower reinforcing properties than 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; further preferred fillers include at least reinforcing fillers, and particularly preferred fillers include a combination of carbon black and silica.

[0093] Carbon black is classified as "NO" according to ASTM standards. "~"N9 (Based on iodine adsorption capacity), traditionally, carbon black is also classified according to the properties of rubber products, such as SAF, HAF, and GPF. Carbon blacks with smaller primary particle sizes, such as N110 (SAF), N220 (ISAF), and N330 (HAF), are sometimes called hard carbon blacks, while those with larger primary particle sizes, such as N550 (FEF), N660 (GPF), and N762 (SRF), are sometimes called soft carbon blacks. These carbon blacks can be used alone or in combination of two or more. Among them, SRF, ISAF, and HAF are preferred, with soft carbon blacks such as SRF being even more preferred.

[0094] The average primary particle size of soft carbon black can be, for example, 42–100 nm, preferably 45–80 nm, more preferably 50–75 nm, and even more preferably 60–70 nm. On the other hand, the average primary particle size of hard carbon black can be, for example, 10–38 nm, preferably 15–35 nm, more preferably 20–33 nm, and even more preferably 25–30 nm.

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

[0096] In addition, in this application, the DBP absorption of carbon black refers to the value (OAN) that can be determined on an uncompressed sample according to JIS K 6217-4 (2017).

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

[0098] In addition, in this application, the iodine adsorption capacity of carbon black can be determined according to the ASTM D1510-17 standard test method.

[0099] The BET specific surface area of ​​carbon black can be, for example, 10–400 m². 2 / g, preferably 15-150m 2 / g (e.g., 20-120mg) 2 / g), further optimized to 25-40m 2 Approximately / g.

[0100] In addition, in this application, BET specific surface area refers to the specific surface area measured using nitrogen gas by the BET method.

[0101] Silica includes dry-process silica, wet-process silica, and surface-treated silica. Furthermore, silica can be classified according to its manufacturing process into dry-process precipitated silica, wet-process precipitated silica, colloidal silica, and precipitated silica. These silicas can be used alone or in combination of two or more. Among these silicas, silica with surface silanol groups (anhydrous silicic acid and hydrated silicic acid) is preferred, as hydrated silicic acid with more surface silanol groups has a stronger chemical bonding force with rubber components.

[0102] The specific surface area for nitrogen adsorption in silica based on the BET method can be, for example, 50–400 m². 2 / g, preferably 70-300m 2 / g, further optimized to 100-250m 2 / g, more preferably 150-200m 2 / g.

[0103] The proportion of filler (especially reinforcing filler) relative to 100 parts by mass of rubber component can be, for example, 10 to 100 parts by mass, preferably 20 to 80 parts by mass (e.g., 50 to 70 parts by mass). The proportion of reinforcing filler relative to the total filler content can be, for example, 50% by mass or more, preferably 75% by mass or more (e.g., 80% by mass or more), more preferably 90% by mass or more, and can also be 100% by mass. The proportion of carbon black (especially soft carbon black) relative to 100 parts by mass of rubber component can be, for example, 0 to 100 parts by mass (e.g., 5 to 80 parts by mass), preferably about 5 to 15 parts by mass. The proportion of silica relative to 100 parts by mass of rubber component can be, for example, 0 to 100 parts by mass (e.g., 10 to 90 parts by mass), preferably about 25 to 75 parts by mass (e.g., 40 to 60 parts by mass). When the product contains both carbon black (especially soft carbon black) and silica, the ratio of the two can be, for example, 5 / 95 to 25 / 75 by mass, preferably around 10 / 90 to 20 / 80. If there is too much carbon black and too little silica, the adhesion may decrease and the connecting tape and cover cloth may peel off easily.

[0104] As for the aforementioned short fibers, examples include those exemplified as fibers constituting fabrics in the aforementioned cover fabric section. These short fibers can be used alone or in combination of two or more. Among these short fibers, polyester fibers (such as PET fibers and other polyalkylene aramid fibers), cellulose fibers (such as cotton), or combinations thereof are preferred. When polyester fibers (such as PET fibers and other polyalkylene aramid fibers) are combined with cellulose fibers (such as cotton), the ratio of the two can be such that the former / the latter (mass ratio) = 50 / 50 to 80 / 20, preferably around 60 / 40 to 70 / 30.

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

[0106] From the perspective of the dispersibility and adhesiveness of short fibers in rubber compositions, short fibers can also undergo conventional bonding treatments (or surface treatments) [e.g., treatment based on a treatment liquid containing adhesive components]. Adhesive components (or surface treatment agents) used for bonding treatments may include, for example, components identical to those exemplified in the aforementioned cover section. They can be used alone or in combination of two or more; the short fibers can also be treated sequentially multiple times with the same or different adhesive components.

[0107] To suppress the compression deformation caused by the belt being squeezed by the pulley (from the perspective of improving lateral pressure resistance), short fibers can be oriented along the belt width direction and embedded in the rubber composition (rubber layer).

[0108] The proportion of short fibers, relative to 100 parts by weight of rubber component, can be, for example, 0 to 50 parts by weight (e.g., 20 to 40 parts by weight), preferably around 0 to 30 parts by weight (especially 0 parts by weight). If the proportion of short fibers is too high, the adhesion to the connecting belt may decrease and the flexibility may decrease.

[0109] As crosslinking agents (or vulcanizing agents), conventional components can be used depending on the type of rubber composition. Examples include: organic peroxides (diacyl peroxides, peroxide esters, dialkyl peroxides, preferably dialkyl peroxides such as 1,3-bis(tert-butylperoxyisopropyl)benzene), sulfur-based vulcanizing agents (e.g., powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersed sulfur, chlorinated sulfur (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), from the perspective of easily improving the adhesion (or peel strength) to the bonding tape, it is preferable to include at least organic peroxides, and more preferably a combination of organic peroxides and sulfur-based vulcanizing agents.

[0110] The proportion of the crosslinking agent (or vulcanizing agent), calculated based on the type of crosslinking agent (or vulcanizing agent) and rubber component, can be selected from approximately 1 to 20 parts by weight (e.g., 1.5 to 10 parts by weight) per 100 parts by weight of rubber component, preferably 2 to 8 parts by weight (e.g., 4 to 7 parts by weight). The proportion of the organic peroxide, calculated based on the solid component, can be approximately 0 to 10 parts by weight (e.g., 1 to 8 parts by weight) per 100 parts by weight of rubber component, preferably 3 to 7 parts by weight. The proportion of the sulfur-based vulcanizing agent, calculated based on the solid component, can be approximately 0 to 5 parts by weight (e.g., 1 to 3 parts by weight) per 100 parts by weight of rubber component, preferably 0.3 to 0.7 parts by weight. When both organic peroxide and sulfur-based vulcanizing agent are combined, their ratio can be approximately 80 / 20 to 99 / 1, preferably approximately 85 / 15 to 95 / 5 (mass ratio). If the proportion of organic peroxides is too small, it may be difficult to improve heat resistance.

[0111] As co-crosslinking agents (crosslinking aids or co-vulcanization aids), known crosslinking aids can be listed, such as: polyfunctional (iso)cyanurates [e.g., triallyl isocyanurate (TAIC), triallyl cyanurate (TAC), etc.], polydienes (e.g., 1,2-polybutadiene), unsaturated carboxylic acid metal salts [e.g., zinc (meth)acrylate, magnesium (meth)acrylate, etc., polyvalent metal salts of (meth)acrylate], oximes (e.g., quinone dioxime), guanidines (e.g., diphenylguanidine), polyfunctional (meth)acrylates [e.g., alkyl diol di(meth)acrylates such as ethylene glycol di(meth)acrylate, butanediol di(meth)acrylate; trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, etc.] Hydrocarbon polyols [poly(meth)acrylates], bismaleimides (aliphatic bismaleimides, such as N,N'-1,2-ethylene bismaleimide, N,N'-hexamethylene bismaleimide, 1,6'-bismaleimide-(2,2,4-trimethyl)cyclohexane and other alkylene bismaleimides; aromatic bismaleimides or aromatic bismaleimides, such as N,N'-m-phenylene bismaleimide, 4-methyl-1,3-phenylene bismaleimide, 4,4'-diphenylmethane bismaleimide, 2,2-bis[4-(4-maleimidephenoxy)phenyl]propane, 4,4'-diphenyl ether bismaleimide, 4,4'-diphenyl sulfone bismaleimide, 1,3-bis(3-maleimidephenoxy)benzene, etc.), 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 (such as N,N'-m-phenylene bismaleimide and other aromatic bismaleimides or aromatic bismaleimides) are preferred, and bismaleimides are used in most cases.

[0112] In terms of solid content, the proportion of co-crosslinking agents (crosslinking aids) such as bismaleimide relative to 100 parts by weight of rubber component can be, for example, 0.1 to 15 parts by weight (e.g., 0.5 to 1.5 parts by weight), preferably around 5 to 15 parts by weight (e.g., 7 to 13 parts by weight). If the co-crosslinking agent (crosslinking aid) (especially bismaleimide, etc.) 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.] and thiazole accelerators [e.g., 2-mercaptobenzothiazole]. Examples of crosslinking accelerators include: zinc salt of 2-mercaptobenzothiazole, 2-mercaptothiazoleline, dibenzothiazole disulfide (MBTS), 2-(4'-morpholine dithio)benzothiazole, sulfenamide accelerators (e.g., N-cyclohexyl-2-benzothiazole sulfenamide (CBS), N,N'-dicyclohexyl-2-benzothiazole sulfenamide), guanidines (diphenylguanidine, di-o-tolylguanidine, etc.), urea or thiourea accelerators (e.g., ethylene thiourea), dithiocarbamates, xanthates, etc. These crosslinking accelerators (or vulcanization accelerators) can be used alone or in combination of two or more. Among these crosslinking accelerators (or vulcanization accelerators), TMTD, CBS, and MBTS are preferred.

[0114] In terms of solid components, the proportion of crosslinking accelerator (or vulcanization accelerator) relative to 100 parts by weight of rubber component can be, for example, 0 to 15 parts by weight (e.g., 0.1 to 10 parts by weight), preferably 0 to 5 parts by weight (e.g., 1 to 4 parts by weight), and more preferably about 0 parts by weight.

[0115] The proportion of metal oxides (such as zinc oxide), converted to solid components, relative to 100 parts by mass of rubber components, can be, for example, 1 to 20 parts by mass (e.g., 2 to 10 parts by mass), preferably around 3 to 7 parts by mass.

[0116] The proportion of softener (such as paraffin oil) should be calculated based on solid components relative to 100 parts by weight of rubber components. For example, it can be 1 to 30 parts by weight (e.g., 2 to 5 parts by weight), preferably around 5 to 15 parts by weight. If there is too little softener (especially paraffin oil or other oils), the adhesion may decrease and the connecting strip and cover cloth may peel off easily.

[0117] The proportion of processing agents or processing aids (such as stearic acid), converted to solid components, relative to 100 parts by mass of rubber components, can be, for example, less than 10 parts by mass (e.g., 0 to 10 parts by mass), preferably around 0.1 to 5 parts by mass (e.g., 0.5 to 1.5 parts by mass).

[0118] The proportion of the adhesive modifier (resorcinol-formaldehyde cocondensate, hexamethoxymethyl melamine, etc.) relative to 100 parts by weight of the rubber component, converted to solid components, can be, for example, 0 to 20 parts by weight (e.g., 0 to 10 parts by weight), preferably 0 to 5 parts by weight, and more preferably about 0 parts by weight.

[0119] Examples of anti-aging agents include: benzimidazole anti-aging agents (2-mercaptobenzimidazole (MBI), 2-mercaptomethylbenzimidazole, or their zinc salts or other metal salts), and aromatic secondary amine anti-aging agents [e.g., 4,4'-dioctyldiphenylamine (ODPA), 4,4'-bis(α,α-dimethylbenzyl)diphenylamine (DCD), etc.]. These anti-aging agents can be used alone or in combination of two or more. Among them, MBI and ODPA are preferred.

[0120] The proportion of the anti-aging agent, converted to solid components, is approximately 0 to 15 parts by weight relative to 100 parts by weight of the rubber component (e.g., 0.1 to 1 part by weight), preferably around 2 to 4 parts by weight.

[0121] The average thickness of the stretch rubber layer can be, for example, 0.5 to 10 mm (e.g., 0.5 to 1.5 mm), preferably 0.6 to 5 mm, and more preferably 0.7 to 3 mm (especially 1 to 2 mm), and can be adjusted appropriately according to the number of layers of cover fabric, etc.

[0122] (Compressed rubber layer) The compression rubber layer can be formed from a vulcanized or cross-linked rubber composition (a cross-linked rubber composition containing rubber components) that is conventionally used as a rubber composition for wrapping V-belts.

[0123] As the rubber component in the crosslinked rubber composition forming the compression rubber layer, examples include the same rubber component as that exemplified in the aforementioned stretch rubber layer section, including the preferred type. The rubber component in the crosslinked rubber composition forming the compression rubber layer is preferably the same type (especially identical) as the rubber component in the crosslinked rubber composition forming the stretch rubber layer.

[0124] Furthermore, the crosslinked rubber composition forming the compression rubber layer may contain conventional additives, or may not contain them, in addition to the aforementioned rubber components, as needed. Examples of additives include, for instance, the same additives as those exemplified in the aforementioned section on the stretch rubber layer, including those in preferred manner.

[0125] Furthermore, the crosslinked rubber compositions forming the compression rubber layer and the stretch rubber layer can be the same or different from each other. When the crosslinked rubber composition forming the compression rubber layer contains short fibers, in order to suppress the compression deformation caused by the belt being squeezed by the pulley (from the perspective of improving lateral pressure resistance), the short fibers can be oriented along the belt width direction and embedded in the rubber composition (rubber layer).

[0126] Furthermore, the compression rubber layer can be a single layer; or it can be formed from multiple layers (e.g., more than two layers, preferably about two to three layers) as needed. When the compression rubber layer is composed of multiple layers, from the perspective of production efficiency, it is preferable to consist of a first compression rubber layer with an outer peripheral side [core layer (adhesive rubber layer) side] and a second compression rubber layer with an inner peripheral side. In addition, when it is composed of multiple layers, the crosslinked rubber compositions forming each compression rubber layer can be the same or different from each other, and it is preferable that the rubber components in the crosslinked rubber compositions can be the same (especially the same). From the perspective of improving lateral pressure resistance, the first compression rubber layer with an outer peripheral side [core layer (adhesive rubber layer) side] can be formed with a crosslinked rubber composition with a higher hardness than the second compression rubber layer with an inner peripheral side; specifically, the hardness of each compression rubber layer can be adjusted by adjusting the type and amount of additives in the crosslinked rubber composition [e.g., fillers, short fibers, crosslinking agents (or vulcanizing agents), co-crosslinking agents or crosslinking aids (or vulcanizing aids), crosslinking accelerators (or vulcanizing accelerators), metal oxides, softeners, processing agents or processing aids, plasticizers, etc.].

[0127] The overall average thickness of the compressed rubber layer can be, for example, 1 to 12 mm, preferably 2 to 10 mm, and more preferably 3 to 8 mm (especially 4.5 to 6 mm), which can be adjusted appropriately according to the number of cover layers, etc. In addition, when the compressed rubber layer has a two-layer structure, the average thickness of the first compressed rubber layer with the outer periphery, relative to the overall average thickness of the compressed rubber layer, can be, for example, about 10 to 90% (e.g., 10 to 60%), preferably about 15 to 50% (e.g., 20 to 40%).

[0128] (Core layer, adhesive rubber layer) The core layer only needs to include a core, and as mentioned above, it can also be a core layer formed solely of a core. Furthermore, in this application, when the core layer is formed solely of a core, the cores arranged at intervals within the belt body are referred to as the core layer; such a core layer includes not only the form where the core is disposed at the interface between the stretch rubber layer and the compression rubber layer, but also the form where, during the manufacturing process, part or all of the core disposed at the interface between the stretch rubber layer and the compression rubber layer is embedded within the stretch rubber layer or the compression rubber layer.

[0129] Furthermore, from the perspective of suppressing interlayer delamination and improving belt durability, the core layer can also be a core layer (adhesive rubber layer) formed from a cross-linked (vulcanized) rubber composition containing a core. A core layer formed from a cross-linked rubber composition containing a core is generally called an adhesive rubber layer, in which the core is embedded within a layer formed from a cross-linked rubber composition containing rubber components. The adhesive rubber layer is located between the stretch rubber layer and the compression rubber layer, bonding the stretch rubber layer, compression rubber layer, and core. In this application, the core layer (adhesive rubber layer) includes not only the form in which the entire core is embedded in the adhesive rubber layer, but also the form in which the core is positioned at the interface between the adhesive rubber layer and the stretch rubber layer or compression rubber layer during the manufacturing process.

[0130] Core The core layer contains cores that are preferably core wires (twisted ropes) arranged at predetermined intervals along the width direction. The core wires are arranged to extend along the length direction of the belt, usually in parallel arrangement along the length direction of the belt at predetermined pitches. When the core (core wire) is embedded in the adhesive rubber layer, only a portion of it needs to be embedded in the adhesive rubber layer; from the perspective of improving durability, it is also possible for the core wire to be embedded in the adhesive rubber layer (the core wire is completely embedded in the adhesive rubber layer).

[0131] As fibers constituting the core thread, the fibers exemplified in the aforementioned section on cover fabrics that constitute the cloth can be listed. These fibers can be used alone or in combination of two or more.

[0132] Among these fibers, from the perspective of high modulus, polyethylene terephthalate, polyethylene 2,6-naphthalate, etc., with C 2-4 Alkylene-C 6-14 Synthetic fibers such as polyester fibers (polyalkylene aryl ester fibers) and polyamide fibers (aramid fibers, etc.) with aryl esters as the main constituent unit, as well as inorganic fibers such as carbon fibers, are widely used; preferred are polyester fibers (especially polyethylene terephthalate fibers and polyethylene naphthalate fibers) and polyamide fibers (especially aramid fibers), and further preferred are polyamide fibers such as aramid fibers.

[0133] These fibers can be used in the form of multifilaments containing multiple filaments. The fineness of the multifilament can be, for example, around 1000 to 3000 dtex (e.g., 1200 to 2000 dtex). The multifilament can include, for example, around 100 to 3000 filaments (e.g., 500 to 2000 filaments), preferably around 700 to 1300 filaments.

[0134] As the core yarn, a twisted rope using multifilament yarns (e.g., multi-twist, single-twist, straight-twist, etc., preferably multi-twist) can typically be used. The average diameter of the core yarn (the diameter of the twisted rope) can 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 rope can be, for example, about 10,000 to 50,000 dtex (e.g., 22,000 to 28,000 dtex). The twisted rope can include, 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 coefficient of the initial twist yarn of the twisted rope can be, for example, about 2 to 4 (e.g., 2.5 to 3.5), and the twist coefficient of the multi-twist yarn can be, for example, about 2 to 4 (e.g., 2.5 to 3.5).

[0135] When the core wire is embedded in the adhesive rubber layer, conventional bonding treatment (or surface treatment) can be performed to improve the adhesion between the core wire and the cross-linked rubber composition forming the adhesive rubber layer [e.g., treatment based on a treatment liquid containing adhesive components]. Examples of adhesive components (or surface treatment agents) used in the bonding treatment include those listed in the aforementioned cover section. These can be used alone or in combination of two or more; treatment can also be performed sequentially multiple times using the same or different adhesive components.

[0136] The aforementioned adhesive rubber layer can be formed from a vulcanized or cross-linked rubber composition (a cross-linked rubber composition containing rubber components) that is conventionally used as a rubber composition for wrapping V-belts.

[0137] As a rubber component in the crosslinked rubber composition forming the adhesive rubber layer, examples include the same rubber component as that exemplified in the aforementioned stretch rubber layer section, including preferred methods. The rubber component in the crosslinked rubber composition forming the adhesive rubber layer is preferably the same (especially identical) rubber component as the rubber component in the crosslinked rubber composition forming the stretch rubber layer and / or compression rubber layer.

[0138] Furthermore, the crosslinked rubber composition forming the adhesive rubber layer may contain, or may not contain, conventional additives in addition to the aforementioned rubber components, as needed. Examples of additives include, for instance, the same additives as those exemplified in the aforementioned section on tensile rubber layers, including those in preferred manner.

[0139] The average thickness of the adhesive rubber layer can be, for example, 0.2 to 5 mm (e.g., 0.3 to 3 mm), preferably around 0.3 to 2 mm (e.g., 0.5 to 1.5 mm), and can be adjusted appropriately according to the number of layers of cover fabric, etc.

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

[0141] The reinforcing layer can be formed from conventional fabric, which can be the same as the fabric exemplified in the aforementioned cover section, including the preferred method.

[0142] To improve adhesion to the compressed rubber layer and the cover fabric, the fabric forming the reinforcing layer can undergo conventional bonding treatment (or surface treatment) [e.g., treatment based on a treatment liquid containing adhesive components]. The adhesive components (or surface treatment agents) used in the bonding treatment can be, for example, the same components exemplified in the aforementioned cover fabric section. They can be used alone or in combination of two or more; or the same or different adhesive components can be used to treat the fabric repeatedly. Preferred fabrics are those with attached rubber components, such as fabrics treated by: soaking (impregnating) the fabric in a rubber paste obtained by dissolving a rubber composition containing rubber components in a solvent, or rubbing (injecting) a solidified version of the aforementioned rubber composition onto the fabric; the aforementioned rubber composition can also include rubber compositions similar to those in the aforementioned cover fabric section, including preferred methods. The bonding treatment only needs to treat at least one surface of the fabric, preferably at least the surface in contact with the compressed rubber layer, and particularly preferably both surfaces.

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

[0144] [Connecting strip (joining component)] As a connecting band, conventional banded V-belts can be used, such as rubber compositions (cross-linked rubber compositions containing rubber components), woven fabrics like canvas, woven curtains, fibrous structures (or fabrics) like mesh (mesh structures or nets), and combinations thereof. From the perspective of effectively suppressing the breakage of the wrapped banded V-belt, the connecting band preferably contains at least fibers.

[0145] When the connecting belt contains fibers, the adhesion (peel force) to the fabric-covered V-belt is often easily reduced; however, the fabric-covered V-belt of the present invention can ensure high adhesion between itself and the non-covered area of ​​the outer peripheral surface of the fabric-covered V-belt, thus simultaneously taking into account adhesion and fracture resistance, and effectively improving the durability of the fabric-covered V-belt.

[0146] As a fiber-containing connecting strip, it can be, for example, a rubber composition containing short fibers (e.g., a rubber composition containing rubber components and short fibers exemplified in the aforementioned tensile rubber layer section), but preferably contains at least a fiber structure (especially canvas, cord fabric, etc.). Therefore, the connecting strip can have at least a connecting reinforcement layer containing a fiber structure, and can also have a protective layer laminated on the outer periphery of the connecting reinforcement layer as needed.

[0147] (Connection Enhancement Layer) The reinforcing layer only needs to contain at least the aforementioned fiber structure (or fabric), and the fiber structure can be used alone or in combination of two or more. Among the fiber structures, woven fabrics are preferred from the perspective of simultaneously suppressing breakage and maintaining flexibility (flexibility) relative to the length direction of the belt, while also achieving excellent balance with production efficiency.

[0148] In the case of curtain fabrics, from the perspective of further improving the resistance to tensile forces acting in the bandwidth direction, curtain fabrics comprising multiple yarns extending in the bandwidth direction are preferred; curtain fabrics comprising multiple first yarns (yarn strips) extending in the bandwidth direction and multiple second yarns having a yarn density (arrangement density) lower than the multiple first yarns and extending in a direction intersecting the bandwidth direction are particularly preferred.

[0149] Furthermore, in this application, a yarn extending along the bandwidth direction refers to a yarn extending substantially parallel to the bandwidth direction. Moreover, "substantially parallel" means that the angle between the direction in which the yarn extends and the bandwidth direction is, for example, about 10° or less (e.g., 0 to 5°), preferably about 3° or less (e.g., 0 to 1°, especially, approximately 0°).

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

[0151] The yarn density of the second yarn body 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] The fibers constituting the first and second yarns can be the fibers listed above as constituting fabrics in the cover fabric section. Among these fibers, polyester fibers and polyamide fibers are preferred as the first yarn, and aliphatic polyamide fibers such as polyamide 66 fibers are particularly preferred. As the second yarn, cellulose fibers are preferred, and cellulose fibers such as cotton fibers are particularly preferred.

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

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

[0155] To improve adhesion to rubber components (crosslinked rubber compositions), the fibrous structure can undergo conventional bonding treatments (or surface treatments) [e.g., treatments based on treatment liquids containing bonding components]. Examples of bonding components (or surface treatment agents) used in the bonding treatment include those listed in the aforementioned cover sheet section. These can be used alone or in combination of two or more; or the same or different bonding components can be used to sequentially treat the structure multiple times.

[0156] The average thickness of the fiber structure is, for example, 0.1 to 0.5 mm, preferably around 0.2 to 0.4 mm. If the fiber structure is too thin, interlaminar delamination and breakage may occur; if the thickness is too thick, the flexibility of the belt may decrease.

[0157] The reinforcing layer can be formed from a fibrous structure (e.g., a fabric treated with a rubber component, etc.), but from the perspective of suppressing the peeling of the fibrous structure, as well as suppressing the peeling between layers (between the wrapping V-belt and / or the protective layer) and suppressing breakage (including suppressing the propagation of defects), it is preferable that the fibrous structure is held in a rubber composition containing a rubber component (the reinforcing layer holds the rubber) (the fibrous structure is embedded in the cross-linked rubber composition).

[0158] As a rubber component constituting the crosslinked rubber composition of the reinforcing layer, examples include the same rubber components as those exemplified in the aforementioned section on the tensile rubber layer, including those in a preferred manner. The rubber component in the crosslinked rubber composition forming the reinforcing layer is preferably the same type (e.g., identical) as the rubber component in the crosslinked rubber composition forming the tensile rubber layer and / or the 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 ethylene-α-olefin elastomers can be 25% by mass or more (e.g., 30-70% by mass), preferably around 35-55% by mass (e.g., 40-50% by mass). If the ethylene content is too high, processability and crack resistance may decrease.

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

[0161] The diene content (especially the ethylene norbornene content) of ethylene-α-olefin elastomers (especially ethylene-α-olefin-diene terpolymers such as EPDM) is, for example, 0.1 to 15% by mass, preferably 1 to 12% by mass (e.g., 5 to 10% by mass), and more preferably 6 to 9% by mass (e.g., 7 to 8% by mass). If the diene content is too high, high heat resistance may not be guaranteed. If the diene content is too low, processability and crack resistance may decrease.

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

[0163] Furthermore, in this application, the Mooney viscosity [ML(1+4)100°C] can be determined using the method according to JIS K 6300-1 (2013), with the following test conditions: using an L-shaped rotor, test temperature 100°C, preheating for 1 minute, and rotor operating time for 4 minutes. Mooney viscosity is measured by filling the chamber with uncrosslinked ethylene-α-olefin elastomer in contact with a grooved roller, and measuring the torque required to rotate the rotor; thus, it is used as an indicator of the rubber's flowability (processability).

[0164] The crosslinked rubber composition connecting the reinforcing layer may contain, or may not contain, conventional additives as needed, in addition to the aforementioned rubber components. Examples of additives include those exemplified in the section on stretched rubber layers, preferably including fillers, crosslinking agents (or vulcanizing agents), crosslinking accelerators (or vulcanization accelerators), metal oxides, processing agents or processing aids, adhesion modifiers, and anti-aging agents. These can be used alone or in combination of two or more.

[0165] As fillers in the crosslinked rubber composition used as the reinforcing layer, reinforcing fillers such as carbon black (hard carbon black such as HAF) and silica are preferred. The proportion of fillers (especially reinforcing fillers) relative to 100 parts by mass of the rubber component is, for example, 30 to 80 parts by mass, preferably 40 to 70 parts by mass (e.g., 50 to 60 parts by mass). The proportion of reinforcing fillers relative to the total filler content is, for example, 50% by mass or more, preferably 75% by mass or more (e.g., 80% by mass or more), more preferably 90% by mass or more, and can also be 100% by mass. The proportion of carbon black (especially hard carbon black) relative to 100 parts by mass of the rubber component is, for example, 20 to 50 parts by mass (e.g., 25 to 45 parts by mass), preferably about 30 to 40 parts by mass. The proportion of silica relative to 100 parts by mass of the rubber component is, for example, 5 to 40 parts by mass (e.g., 8 to 35 parts by mass), preferably about 10 to 30 parts by mass (e.g., 15 to 25 parts by mass). When the material contains both carbon black (especially hard carbon black) and silicon dioxide, the ratio (mass ratio) of the two can be, for example, 45 / 55 to 80 / 20, preferably around 55 / 45 to 70 / 30.

[0166] The crosslinking agent (or vulcanizing agent) in the crosslinked rubber composition used as the reinforcing layer is preferably a sulfur-based vulcanizing agent. The proportion of the crosslinking agent (or vulcanizing agent) (especially a sulfur-based vulcanizing agent) is, in solids content, about 0.1 to 3 parts by weight (e.g., 0.3 to 2 parts by weight) relative to 100 parts by weight of the rubber component, depending on the type of crosslinking agent (or vulcanizing agent) and the rubber component, preferably about 0.5 to 1.5 parts by weight.

[0167] As a crosslinking accelerator (or vulcanization accelerator) in the crosslinked rubber composition used as a reinforcing layer, MBTS or the like is preferred. The proportion of the crosslinking accelerator (or vulcanization accelerator), converted to solids, relative to 100 parts by weight of the rubber component, can be, for example, 0.1 to 3 parts by weight (e.g., 0.3 to 2 parts by weight), preferably about 0.5 to 1.5 parts by weight.

[0168] The proportion of metal oxides (such as zinc oxide) in the crosslinked rubber composition that forms the reinforcing layer, converted to solid components, is, for example, 1 to 20 parts by mass (e.g., 2 to 10 parts by mass) relative to 100 parts by mass of rubber components, preferably about 3 to 7 parts by mass.

[0169] The proportion of processing agents or processing aids (such as stearic acid) in the crosslinked rubber composition that forms the reinforcing layer, converted to solid components, relative to 100 parts by mass of rubber components, can be, for example, less 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).

[0170] The proportion of adhesive modifiers (resorcinol-formaldehyde cocondensate, hexamethoxymethyl melamine, etc.) in the crosslinked rubber composition that forms the reinforcing layer, converted to solid components, relative to 100 parts by weight of rubber components, can be, for example, 0.1 to 20 parts by weight (e.g., 1 to 10 parts by weight), preferably about 2 to 8 parts by weight (e.g., 3 to 5 parts by weight).

[0171] DCD is preferred as an anti-aging agent in the crosslinked rubber composition used as a reinforcing layer. The proportion of the anti-aging agent, converted to solid content, relative to 100 parts by weight of the rubber component, can be, for example, 0.1 to 15 parts by weight (e.g., 1 to 3 parts by weight), preferably about 1.5 to 2.5 parts by weight.

[0172] The connection reinforcement layer can be used alone (single layer) or in combination of two or more, but it is preferred to use it alone (single layer).

[0173] The average thickness of the reinforcing layer is, for example, 0.4 to 1.4 mm, preferably about 0.5 to 1 mm. If the fabric layer is too thin, interlayer peeling or breakage may occur; if the thickness is too thick, the flexibility of the belt may decrease.

[0174] (Protective layer) The connecting strip (bonding member) may be formed by the connecting reinforcement layer alone, but from the perspective of effectively preventing damage to the fiber structure in the connecting reinforcement layer (e.g., damage caused by foreign objects from the back of the strip), a protective layer may be stacked on the connecting reinforcement layer (on the outer peripheral side of the strip or the outermost layer).

[0175] The protective layer can be formed from a rubber sheet of a conventional cross-linked rubber composition (e.g., a rubber sheet of a rubber composition containing short fibers) or from a conventional fabric (e.g., the fabric exemplified in the aforementioned cover section). These protective layers can be used alone or in combination of two or more. Among these protective layers, those formed from a cross-linked rubber composition are preferred.

[0176] The rubber component in the crosslinked rubber composition serving as the protective layer may include, among other things, the same rubber component as that exemplified in the aforementioned section on the stretching rubber layer, including preferred embodiments. Preferably, the rubber component in the crosslinked rubber composition forming the protective layer is the same type (especially identical) as the rubber component in the crosslinked rubber composition forming the stretching rubber layer.

[0177] Furthermore, the crosslinked rubber composition forming the protective layer may contain conventional additives, or may not contain them, in addition to the aforementioned rubber components, as needed. Examples of additives include those similar to those exemplified in the section on tensile rubber layers, including those in preferred embodiments.

[0178] Furthermore, the crosslinked rubber compositions forming the protective layer and the stretching rubber layer can be the same or different from each other. When the crosslinked rubber composition forming the protective layer contains short fibers, from the perspective of improving fracture resistance and wear resistance when in contact with the flange of the idler wheel, tensioner wheel, etc. on the back side of the belt, the short fibers can be oriented along the width direction and embedded in the rubber composition (rubber layer).

[0179] In addition, the average thickness of the protective layer is, for example, 0.4 to 2 mm, preferably 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; if the thickness is too thick, the flexibility of the belt may decrease.

[0180] The connecting strip (joining component) may have multiple protective layers (e.g., 2 to 3 layers) as needed, preferably one layer.

[0181] [Manufacturing method of fabric-covered V-belt] The wrapped V-belt is obtained as follows: after preparing an uncrosslinked (unvulcanized) wrapped V-belt section (wrapped V-belt section precursor), it is obtained by a linking process of linking multiple unvulcanized wrapped V-belt sections (wrapped V-belt section precursors) with a linking belt (linking belt precursor).

[0182] As a method for manufacturing an uncrosslinked (unvulcanized) fabric-covered V-belt (precursor to fabric-covered V-belt), for example, the method described in Japanese Patent Application Publication No. 6-137381 and Booklet No. WO2015 / 104778 can be used. Specifically, the unvulcanized fabric-covered V-belt portion (precursor to the fabric-covered V-belt portion) can be obtained through the following processes: a winding process in which an unvulcanized compression rubber layer sheet obtained by calendering is cut and mounted on a mantle; an unvulcanized first adhesive rubber layer sheet is wound around the compression rubber layer sheet; a core is wound around the wound first adhesive rubber layer sheet; and then an unvulcanized second adhesive rubber layer sheet and an unvulcanized stretch rubber layer sheet are wound sequentially around the wound core; a cutting process in which the obtained annular laminate is cut (circumcised) on the mantle; a trimming process in which the cut annular laminate is mounted on a pair of pulleys and cut into a V-shape while rotating; and a cover covering process (covering process or cover wrapping process) in which the obtained unvulcanized belt body portion (precursor to the belt body portion) is covered around with a cover cover precursor [e.g., a cover fabric (cloth) with an uncrosslinked rubber composition attached].

[0183] In addition, during the winding process, when the compressed rubber layer is multi-layered, the stacked sheet containing multiple compressed rubber layers can be cut and installed on the cover; furthermore, the first adhesive rubber layer sheet and the second adhesive rubber layer sheet can be wound only on one side, or neither can be wound (adhesive rubber layers may not be formed).

[0184] The method for manufacturing the wrapped V-belt of the present invention includes at least: a covering step, in which a cover fabric precursor is used to cover a belt main body precursor to form a wrapped V-belt precursor; and a connecting step, in which the outer peripheral surfaces of multiple wrapped V-belt precursors obtained in the covering step are connected using a connecting belt precursor [e.g., a connecting belt containing fibers (especially fibrous structures) and an uncrosslinked rubber composition]. In the covering step, at least the inner peripheral surface and both sides of the belt main body precursor are covered, but at least a portion of the outer peripheral surface (the aforementioned uncovered area) is not covered. The manufacturing method does not include a removal step (the step described in Patent Documents 2-3) of cutting off or removing the cover fabric precursor obtained in the covering step that covers the outer peripheral surface of the wrapped V-belt precursor. Therefore, steps can be omitted, and wrapped V-belts with excellent wear resistance and the ability to suppress connecting belt peeling can be manufactured with high production efficiency and low cost.

[0185] In addition, the manufacturing method of the present invention can also easily and efficiently manufacture a wrapped V-belt in which the entire outer peripheral surface of the wrapped V-belt portion is an uncovered area (excluding the covered area). However, from the perspective of being able to manufacture with even higher production efficiency, it is preferable to manufacture a wrapped V-belt with both covered and uncovered areas.

[0186] In the covering process, a seamless (continuous) cover sheet can be used to cover at least the inner circumferential surface, both sides, and at least one side of the outer circumferential surface of the main body of the belt (the area corresponding to the covered area, preferably both sides). Furthermore, the width of the cover sheet can be less than the perimeter of the cross-sectional shape of the main body of the belt perpendicular to its length direction (i.e., the total length of the inner circumferential surface, both sides, and the outer circumferential surface of the cross-sectional shape); or it can be greater than the total length of the inner circumferential surface and both sides of the cross-sectional shape, depending on the area ratio of the uncovered area, etc. Alternatively, the width direction of the cover sheet can be oriented perpendicular to the belt length direction (the length direction of the cover sheet can be oriented towards the belt length direction) to cover the main body of the belt.

[0187] Previously, when covering the main body of the belt with a cover sheet, for example, Figure 2 During the covering process, the main body of the belt is wound between two pulleys and rotated. A cover fabric front, wound into a cylindrical shape, is fed out to the outer peripheral side of the rotating main body of the belt and pressed against the rollers. This causes the cover fabric front, which is in contact with the outer peripheral side, to be wound in a cylindrical shape like a tubular conveyor while being fed out and pressed against the rollers from the outside, thus wrapping the main body of the belt. The cover fabric front is then overlapped on the inner peripheral side, thereby forming the V-belt covering front.

[0188] In contrast, in this invention, the main body of the belt can be rotated (run) between two pulleys with its inner and outer circumferential sides in opposite directions to those in the conventional method (the wider side faces the inner circumferential side, and the narrower side faces the outer circumferential side), and covered with a cover fabric front of predetermined width (as mentioned above, a continuous cover fabric front with a width smaller than the perimeter of the cross-sectional shape perpendicular to the length direction of the main body of the belt). That is, the cover fabric front of predetermined width is brought into contact with the narrower side of the outer circumferential side of the rotating main body of the belt (which becomes the inner circumferential side of the wrapped V-belt), and, as in the conventional method, is pressed against it by rollers to follow the shape of the main body of the belt, thereby covering both sides and the wider side of the inner circumferential side (which becomes the outer circumferential side of the wrapped V-belt). However, since the width of the cover fabric front is smaller than the aforementioned perimeter, at least one side of the wider side of the inner circumferential side (which becomes the outer circumferential side of the wrapped V-belt) is covered (corresponding to the covered area), while an uncovered area (corresponding to the uncovered area) is formed.

[0189] Furthermore, as mentioned above, when using a seamless cover fabric precursor to manufacture a V-belt precursor with the entire outer periphery of the belt as an uncovered area, it is considered difficult to align the cover fabric precursor (align the two ends of the cover fabric precursor in the width direction with the two ends of the outer periphery of the belt body precursor) for the following reasons. First, the cover fabric precursor is adhesive and therefore cannot be adjusted once it comes into contact with the belt body precursor. Moreover, the belt body precursor is a soft, uncrosslinked rubber composition, and is prone to deformation during edge trimming and other processes. Therefore, it is difficult to keep the belt body precursor running straight when it comes into contact with the cover fabric precursor (it is easy to run off-center), and positional deviation from the cover fabric precursor is likely to occur. In addition, during the crosslinking molding process (crosslinking molding process) described later, it is believed that the rubber composition will flow within the mold due to pressure, etc., and positional deviation will also occur. Therefore, if you want to manufacture a fabric-covered V-belt where the entire outer perimeter of the belt is an uncovered area (the proportion of uncovered area is 100%), the belt length direction is prone to have parts that are not covered by the cover fabric due to the influence of positional deviation, which tends to increase the defect rate.

[0190] However, if, as in the covering process described above, the width of the cover fabric precursor is adjusted to the predetermined length to cover the inner circumference and both sides of the belt, and at least one side (preferably both sides) is covered by folding the end of the cover fabric precursor towards the outer circumference, not only can the generation of portions of the belt side not covered by the cover fabric be effectively suppressed, but the removal process can also be reduced without material loss. Therefore, the fabric-covered V-belt precursor can be manufactured easily, efficiently, and with high productivity. Furthermore, the resulting fabric-covered V-belt precursor not only improves adhesion to the connecting belt through the uncovered area, but also effectively suppresses the cover fabric from peeling off from the boundary with the connecting belt because at least one side (preferably both sides) on the outer circumference forms a covered area after being folded in from the side.

[0191] In addition, when the seamless cover fabric is used to cover in an endless loop, one end and the other end of the cover fabric in the longitudinal direction can be adjacent without overlapping, or they can partially overlap. Preferably, the two ends in the longitudinal direction can partially overlap and cover in an endless loop.

[0192] The fabric V-belt precursor obtained in the covering process can be connected to the connecting belt precursor (e.g., a connecting belt containing an uncrosslinked rubber composition) using conventional methods (connecting process). For example, multiple unvulcanized fabric V-belts (fabric V-belt precursors) are embedded into an inverted trapezoidal groove formed on a cylindrical or annular lower vulcanizing mold, and the connecting belt precursor is then placed on its radially outer portion. In setting the connecting belt precursor, the connecting belt precursor is wound circumferentially around the multiple unvulcanized fabric V-belts arranged in the width direction. The connecting belt precursor and the multiple unvulcanized fabric V-belts (fabric V-belt precursors) set as described above are then subjected to a crosslinking molding process (vulcanization process) [crosslinking molding process (vulcanization process)] while being clamped between the upper and lower vulcanizing molds and subjected to pressure. After this crosslinking molding process (vulcanization process), a crosslinked sleeve (vulcanized sleeve) is formed, in which the multiple fabric V-belts are connected and bonded by the connecting belt. The cross-linked sleeve (vulcanized sleeve) formed in this way is cut to a predetermined width to form a wrapped V-belt with a predetermined number of wrapped V-belt sections.

[0193] In the crosslinking molding process (vulcanization), the crosslinking (vulcanization) temperature can be selected according to the type of rubber component, for example, 120-200°C, preferably around 150-180°C. The pressure in the crosslinking molding process (vulcanization) is, for example, 1-2 MPa, preferably around 1-1.5 MPa. Furthermore, for the rubber sheets containing short fibers, the short fibers can be aligned (oriented) along the calendering direction by calendering using calendering rolls or the like.

[0194] Furthermore, the connecting tape precursor and each uncrosslinked (unvulcanized) wrapped V-belt portion (wrapped V-belt portion precursor) are bonded together, for example, using adhesive components attached to the connecting tape precursor and the cover fabric precursor of the covered area through an adhesive treatment, and the tensile rubber layer exposed in the uncovered area. For example, when a fabric treated with a rubbing (rubbing in) solid rubber composition is used as the connecting tape, the connecting tape precursor, the cover fabric precursor of the covered area, and the tensile rubber layer exposed in the uncovered area are bonded together through the crosslinking (vulcanization) reaction of the rubbing rubber composition. That is, the process of setting the connecting tape precursor on the unvulcanized wrapped V-belt portion includes the uncrosslinked (unvulcanized) tape bonding step, in which multiple unvulcanized wrapped V-belt portions are bonded together via the connecting tape as a connecting part. The unvulcanized tape bonding step is not limited to this method; the connecting tape can also be constructed by winding multiple layers of rubber sheets (e.g., sheets for connecting reinforcement layers, sheets for protective layers, and their laminates) to form the connecting tape.

[0195] The number of fabric-covered V-belt sections in a fabric-covered V-belt assembly can be two or more, for example, two to ten, preferably two to eight, and more preferably two to six. Adjacent fabric-covered V-belt sections only need to be aligned parallel to each other along the belt length direction; there is no limitation to specific arrangements. Figure 4 While the belts can be arranged with intervals, they can also be arranged without intervals. From the perspective of production efficiency, it is preferable to arrange adjacent wrapped V-belt sections with intervals. The interval between adjacent wrapped V-belt sections is, for example, 1.7 to 4.3 mm, preferably 2 to 4.1 mm, and more preferably about 2.3 to 3.9 mm. Furthermore, the interval between the wrapped V-belt sections refers to the interval at the outer circumference of the belt. The connecting belt is only required to connect the wrapped V-belt sections and is not limited to a specific arrangement. Figure 4 In a form where the belt is integrated by making full contact with the outer peripheral surface of each wrapped V-belt section, the outer peripheral surface of the wrapped V-belt section can also have an area that does not contact the connecting belt. From the perspective of belt durability, it is preferable that the entire outer peripheral surface of each wrapped V-belt section is in contact with the connecting belt and integrated.

[0196] Fabric-covered V-belts can also be used in high-load, long-span (long inter-axle distance) layouts such as large agricultural machinery. The width of the outer circumference of each fabric-covered V-belt section can be, for example, about 15 to 60 mm, and the thickness of each fabric-covered V-belt section can be, for example, 10 to 20 mm (e.g., 10 to 15 mm).

[0197] The total length of the fabric-covered V-belt can be, for example, more than 50 inches, more than 200 inches (508cm), or around 220 to 500 inches.

[0198] Because cloth-covered V-belts are suitable for long-span layouts, the maximum span length (the distance between the pulleys) can be more than 1000mm, for example, it can be around 2000 to 5000mm.

[0199] The fabric-covered V-belt of the present invention is suitable for high-load applications and is suitable for high-horsepower machinery. The load (reference transmission capacity) applied to a single fabric-covered V-belt section can be 10 PS or more, preferably 20 PS or more, and even more preferably 22 PS or more (for example, about 22 to 30 PS).

[0200] In the fabric-covered V-belt of the present invention, the adhesion (close bonding) between the fabric-covered V-belt portion and the connecting belt is excellent. The peel force (or adhesive strength) between the fabric-covered V-belt portion and the connecting belt can be, for example, 50 to 150 N / cm (e.g., 60 to 130 N / cm), preferably 70 to 125 N / cm (e.g., 80 to 122 N / cm), and more preferably around 90 to 120 N / cm (e.g., 95 to 120 N / cm).

[0201] In addition, in this application, the peel force (adhesive strength) between the fabric V-belt portion and the connecting belt can be measured by the method described in the embodiments.

[0202] The fabric-coated V-belt of the present invention exhibits excellent wear resistance. The wear rate of the fabric-coated V-belt before and after operation under predetermined conditions can be, for example, 0.5 to 2% (e.g., 0.7 to 1.7%), preferably 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 addition, in this application, the wear rate of the fabric-covered V-belt can be measured by the method described in the examples.

[0204] The fabric-covered V-belt of the present invention exhibits excellent resistance to lateral pressure. The lateral ride-out variation of the fabric-covered V-belt can 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 can be around 0.5 to 0.52 mm.

[0205] In addition, in this application, the lateral offset change of the wrapped V-belt can be measured by the method described in the embodiments.

[0206] The fabric-covered V-belt of the present invention exhibits excellent durability. The durability of the fabric-covered V-belt can 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 especially around 280 hours or more (e.g., 290 to 315 hours).

[0207] In addition, in this application, the durability of the fabric-covered V-belt can be determined by the method described in the embodiments.

[0208]

Example

[0209] [Rubber Composition] (Raw 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 (ethylene norbornene content) 4.9% by mass. EPDM2: Mitsui Chemicals, Inc. manufactures “EPT4045M”, Mooney viscosity [ML (1+4) 100℃] approx. 45, ethylene content 45% by mass, diene content (ethylene norbornene content) 7.6% by mass. Cotton staple fiber: Hashimoto-made "cotton cut yarn", with an average fiber length of 6mm. Polyester staple fiber: Hongyu staple fiber makes "PET cut yarn" with an average fiber length of 3mm. Carbon black SRF: Manufactured by Tokai Carbon Black Co., Ltd., "Seast S", DBP absorption 68mL / 100g, BET specific surface area 27m². 2 / g, iodine adsorption capacity 26g / kg. Carbon Black ISAF: Manufactured by Tokai Carbon Black Co., Ltd., "Seast 6", DBP absorption 114mL / 100g, BET specific surface area 119m² 2 / g, iodine adsorption capacity 121g / kg. Carbon black HAF: Manufactured by Tokai Carbon Black Co., Ltd., "Seast 3", DBP absorption 101mL / 100g, BET specific surface area 79m² 2 / g, iodine adsorption capacity 80g / kg. Clay: "Catalpo" manufactured by Sanyo Clay Industry Co., Ltd. Silica: "Ultrasil VN3" manufactured by Evonik Industries, with a BET specific surface area of ​​180 m². 2 / g. Paraffinic oil: "Diana Process Oil PW90" manufactured by Idemitsu Kosan Co., Ltd. Anti-aging agent MBI (2-mercaptobenzimidazole): Manufactured by Ouchi Shinsei Chemical Industry Co., Ltd. as "Nocrac MB-O". Anti-aging agent ODPA (octyl diphenylamine): Manufactured by Ouchi Shinsei Chemical Industry Co., Ltd. as "Nocrac AD-F". Anti-aging agent DCD (4,4'-bis(α,α-dimethylbenzyl)diphenylamine): Manufactured by Ouchi Shinsei Chemical Industry Co., Ltd. as "Nocrac CD". Zinc oxide: Sakai Chemical Industry Co., Ltd. manufactures "two types of zinc oxide". Stearic acid: "Tsubaki stearic acid" manufactured by Nippon Oil Co., Ltd. Crosslinking accelerator TMTD (tetramethylthiuram disulfide): Manufactured by Ouchi Shinsei Chemical Industry Co., Ltd. as "Noxeller TT". Crosslinking accelerator CBS (N-cyclohexyl-2-benzothiazole sulfenamide): Manufactured by Ouchi Shinsei Chemical Industry Co., Ltd. as "Noxeller CZ". Crosslinking accelerator MBTS (dibenzothiazole disulfide): Manufactured by Ouchi Shinsei Chemical Industry Co., Ltd. as "Noxeller DM". Co-crosslinking agent MPBM (N,N'-m-phenylenemaleimide): Manufactured by Ouchi Shinsei Chemical Industry Co., Ltd. as "Varnock PM". Adhesion modifier A (resorcinol-formaldehyde cocondensate): manufactured by INDSPEC Chemical Corporation as "Penacolite Resin (B-18-S)". Adhesion modifier B (hexamethoxymethyl melamine): manufactured by SINGH PLASTICISER & RESINS, "POWERPLAST PP-1890S". Organic peroxide: 1,3-bis(tert-butylperoxyisopropyl)benzene. Sulfur (powdered sulfur): Manufactured by Meiyuan Chemical.

[0210] (Preparation of uncrosslinked calendered rubber sheets and uncrosslinked block rubber compositions for wiping) The rubber compositions R1 to R2 shown in Table 1 are mixed in an internal mixer, and the mixed rubber is passed through calendering rolls to produce uncrosslinked (unvulcanized) calendered rubber sheets of predetermined thickness, which are used as sheets for compression rubber layers, adhesive rubber layers, stretching rubber layers and / or protective rubber layers.

[0211] In addition, the rubber composition R1 shown in Table 1 was mixed in an internal mixer to prepare a block-shaped uncrosslinked (unvulcanized) rubber composition for use as a cover cloth precursor.

[0212] Furthermore, the rubber composition R3 shown in Table 1 is mixed in an internal mixer, and the mixed rubber is passed through calender rolls to produce an uncrosslinked (unvulcanized) calendered rubber sheet of a predetermined thickness, which is used as a connecting reinforcement layer for forming the precursor of the connecting belt.

[0213]

[0214] [Core wire (treated cord)] Three bundles of aramid fibers, each 1670 dtex (1000 filaments), are combined and twisted in the S-direction with a twist factor of 3.0 to produce a nascent yarn. Five of these nascent yarns are then combined and twisted in the Z-direction with a twist factor of 3.0 to produce a twisted rope (retwisted yarn) with a total fineness of 25050 dtex (15000 filaments) and a diameter of 1.9 mm. This twisted rope, after undergoing bonding treatment, is used as the core yarn. The twist factor TF is calculated using the following formula.

[0215] TF = TN × D0.5 / 960

[0216] [In the formula, TF represents the twist coefficient, TN represents the twist per meter, and D represents the yarn fineness (tex)]

[0217] [Cover fabric precursor (treated canvas)] The cover fabric is made of canvas that has undergone bonding and wiping treatment (treated canvas). Specifically, the treated canvas uses a 20s / 3 (20-count three-ply twisted) blended yarn of polyester and cotton in a 50 / 50 mass ratio for both warp and weft, woven in plain weave with a warp density of 75 ends / 50mm and a weft density of 75 ends / 50mm, resulting in an area weight of 280g / m². 2 The canvas was impregnated in RFL solution (a mixture of 2.6 parts by weight of resorcinol, 1.4 parts by weight of 37% formaldehyde, 17.2 parts by weight of vinylpyridine-styrene-butadiene copolymer latex (manufactured by Zeon Corporation, Japan), and 78.8 parts by weight of water), and after drying, it underwent wide-angle treatment to make the angle between the warp and weft yarns 120 degrees. The resulting wide-angle canvas was then treated by rubbing in rubber composition R1 on both sides (rubbing) to obtain treated canvas (approximately 500 g / m²). 2 (Approximately 0.6mm thick).

[0218] [Connecting reinforcement layer precursor (treated fabric)] The curtain fabric is treated with bonding and rubber sheet lamination as a precursor for the connecting reinforcement layer. Specifically, the following curtain fabric is used: a curtain-like fabric woven with a warp density of 120 threads / 50mm and a weft density of 5 threads / 50mm using 470dtex nylon 66 single-twist rope (0.22mm diameter) and 40-count cotton yarn (0.1mm diameter) as weft, is immersed in RFL solution (a mixture of 2.6 parts by weight of resorcinol, 1.4 parts by weight of 37% formaldehyde, 17.2 parts by weight of vinylpyridine-styrene-butadiene copolymer latex (manufactured by Zeon Corporation, Japan) and 78.8 parts by weight of water), and after drying, a rubber sheet for the connecting band of rubber composition R3 is laminated on both sides to obtain the treated curtain fabric (approximately 0.7mm thick).

[0219] [Comparative Example 1 and Examples 1-6] (Preparation of uncrosslinked rubber tape 1 (stretched rubber layer is R1)) A core wire is spirally wound around the outer periphery of a compression rubber layer sheet (5.4 mm thick) of R1, which is wound around the outer periphery of a cylindrical drum. A stretch rubber layer sheet (1.6 mm thick) of R1 is then layered on its outer periphery to form a cylindrical uncrosslinked sleeve composed of an uncrosslinked rubber layer and a core wire. That is, the outermost periphery of the uncrosslinked sleeve exposes the rubber composition R1. The resulting uncrosslinked sleeve is then circumferentially cut while positioned around the outer periphery of the cylindrical drum to form an annular uncrosslinked rubber strip 1.

[0220] (Edge trimming process and fabric covering process (covering process)) The uncrosslinked rubber strip 1 is removed from the drum, and both sides of the uncrosslinked rubber strip are cut (edge ​​trimming) at a predetermined angle to form a V-shaped cross-section (edge ​​trimming process). The uncrosslinked rubber strip with the V-shaped cross-section (the main body of the strip: an uncrosslinked V-belt including a stretch rubber layer, a core (core wire), and a compression rubber layer) is covered with a cover fabric to form the uncrosslinked fabric-covered V-belt part 1 (covering process).

[0221] In the covering process, cover fabric precursors of different widths are used. The width direction of the cover fabric precursor is circumferentially aligned with the length direction of the tape in the direction perpendicular to the tape length (i.e., the length direction of the cover fabric precursor is aligned with the tape length direction), and it is wound around the inner circumferential side of the uncrosslinked rubber tape. This causes the proportion of the non-covered area on the outer circumferential surface (back side) of the wrapped V-belt portion after the bonding process (after crosslinking) to change to the proportion shown in Table 2 below. That is, Examples 1 to 6 are formed as follows: Figure 4 The shape shown is different from that in Comparative Example 1. Figure 2 In this method, the cover covering the inner circumference is made into a single layer, and the two ends of the cover are formed facing each other on the outer circumference side.

[0222] In addition, the cover fabric front is configured with the following orientation: the warp and weft directions are tilted at 60° relative to the length direction of the belt.

[0223] (Preparation of the banded V-belt (connection process)) The obtained six uncrosslinked V-belt portions 1 are embedded into the annular groove formed on the lower crosslinking mold. Then, on the radially outer portion, the aforementioned treated fabric (connecting reinforcement layer precursor) and the protective layer rubber sheet (1.3 mm thick) of R1 are set as the connecting belt precursor. That is, in setting the connecting belt precursor, the treated fabric and the protective layer rubber sheet are sequentially wound around the circumference (belt length direction) of the six uncrosslinked V-belt portions arranged in the width direction to set the connecting belt precursor for the six uncrosslinked V-belt portions. In addition, the treated fabric is configured such that the length direction of the warp yarn is approximately parallel to the width direction of the belt, and the length direction of the weft yarn is approximately parallel to the circumference direction of the belt.

[0224] The pre-set connecting tape and the 6 uncrosslinked fabric-covered V-belt sections 1 are sandwiched between the upper crosslinking mold and the lower crosslinking mold, and pressure is applied to 1.2 MPa. Crosslinking is carried out at a crosslinking temperature of 160°C to obtain a crosslinked tape 1 formed by connecting and combining the 6 fabric-covered V-belt sections 1 (HB type of ASABE standard, tape length 1600 mm).

[0225] The obtained cross-linked tape 1 is cut to obtain a fabric-covered bundled V-belt 1 with 3 fabric-covered V-belt sections 1 (cross-sectional dimensions: width 54.6 mm × thickness 12.7 mm).

[0226] [Comparative Example 2, Examples 7-9 and Reference Example 1] (Preparation of uncrosslinked rubber tape 2 (stretched rubber layer is R2)) A second compression rubber layer sheet of R1 (3.4 mm thick), a first compression rubber layer sheet of R2 (1.5 mm thick), and an adhesive rubber layer sheet of R1 (0.5 mm thick) are sequentially stacked on the outer circumferential surface of a cylindrical drum. Then, a core wire is spirally wound around it, and subsequently, an adhesive rubber layer sheet of R1 (0.5 mm thick) and a stretch rubber layer sheet of R2 (1.1 mm thick) are sequentially stacked on its outer circumferential surface to form a cylindrical uncrosslinked sleeve composed of an uncrosslinked rubber layer and a core wire. That is, the outermost circumferential surface of the uncrosslinked sleeve exposes the rubber composition R2. The resulting uncrosslinked sleeve is then circumferentially cut while positioned on the outer circumference of the cylindrical drum to form an annular uncrosslinked rubber strip 2. Furthermore, in the R2 rubber layer containing short fibers, the length direction of the short fibers is arranged approximately parallel to the width direction of the strip.

[0227] (Edge trimming process and fabric covering process (covering process)) Except for using uncrosslinked rubber tape 2 to replace uncrosslinked rubber tape 1, and changing the proportion of the non-covered area on the outer peripheral surface (back side) of the wrapped V-belt portion to the proportion shown in Table 3 below during the covering process, the edge trimming and covering processes in [Comparative Examples 1 and Examples 1-6] are performed in the same manner to form the uncrosslinked wrapped V-belt portion 2. That is, Examples 7-9 are formed as follows: Figure 4 The shape shown; refer to Example 1 in Figure 3 In Comparative Example 2, the cover fabric covering the inner circumference is a single layer; Figure 2 In this case, the cover covering the inner circumference is made into a single layer and the two ends of the cover covering on the outer circumference side face each other.

[0228] (Preparation of the banded V-belt (connection process)) Except that the protective layer rubber sheet of R2 (1.3 mm thick) was used instead of the protective layer rubber sheet of R1 (1.3 mm thick), and the length direction of the short fibers in the protective layer rubber sheet of R2 was arranged to be approximately parallel to the width direction of the belt, the same connection process as in [Comparative Example 1 and Examples 1 to 6] was performed to obtain a crosslinked belt 2 formed by connecting and bonding 6 wrapped V-belt portions 2 (HB type of ASABE standard, belt length 1600 mm) with the connecting belt.

[0229] The obtained cross-linked tape 2 is cut to produce a wrapped V-belt 2 with 3 wrapped V-belt sections 2 (cross-sectional dimensions: width 54.6 mm × thickness 12.7 mm).

[0230] [Examples 10-12] By changing the number of cover layers in Examples 4-6 (stretched rubber layer: R1, proportion of non-covered area: 50%, 70%, 90%, number of cover layers: 1) to 2 layers, a product with... Figure 6 The cross-sectional shape of the wrapped V-belt is shown. Specifically, in the covering process, the uncrosslinked rubber belt 1 underwent two covering pre-coat wrapping treatments; and to ensure the cross-sectional dimensions were consistent with Examples 4-6, the thicknesses of the compression rubber layer sheet and the stretch rubber layer sheet were adjusted to be thinner as the number of covering layers increased. Otherwise, the process was the same as in Examples 4-6, resulting in a wrapped V-belt with three wrapped V-belt sections 1. Furthermore, in the covering process, in order to... Figure 6 The cross-sectional shape shown is used to perform a covering treatment in such a way that the outer cover (first cover) is wrapped along the inner cover (second cover) (so that both the first cover and the second cover cover cover the same area of ​​the outer periphery of the main body).

[0231] [Examples 13-14] A wrapped V-belt was prepared by changing the number of cover layers in Example 11 (stretched rubber layer: R1, proportion of non-covered area: 70%, number of cover layers: 2 layers) to 3 layers (Example 13) or 4 layers (Example 14). Specifically, the uncrosslinked rubber strip 1 was wrapped with the cover material 3 or 4 times during the covering process; and to ensure uniform cross-sectional dimensions, the thicknesses of the compression rubber layer sheet and the stretch rubber layer sheet were adjusted to be thinner as the number of cover layers increased. Otherwise, the process was the same as in Example 11, resulting in a wrapped V-belt with 3 wrapped V-belt sections 1. Furthermore, in the covering process, to ensure... Figure 6 Based on the cross-sectional shape, the covering was applied in such a way that each cover was wrapped along the adjacent cover (so that all cover were covered in the same area of ​​the outer periphery of the main body).

[0232] [Examples 15-16] By changing the proportion of the non-covered area of ​​the inner cover (second cover) in Examples 11-12 (stretched rubber layer: R1, proportion of non-covered area: 70% or 90%, number of cover layers: 2) to 100%, a product with Figure 7 The cross-sectional shape of the wrapped V-belt is shown. That is, in the covering process, during the first covering process, the cover fabric precursor is used to cover only the inner circumferential surface and both sides of the uncrosslinked rubber belt 1 without covering the outer circumferential surface; during the second covering process, both sides of the outer circumferential surface are covered, so that the proportion of the non-covered area of ​​the outer cover fabric (first cover fabric) is 70% (Example 15) or 90% (Example 16); otherwise, it is carried out in the same way as in Examples 11 to 12, and a wrapped V-belt with 3 wrapped V-belt portions 1 is obtained.

[0233] [Reference Example 2] Not only the inner cover (second cover) but also the proportion of the non-covered area of ​​the outer cover (first cover) is changed to 100% (the second cover wrapping process also uses the cover precursor to cover only the inner circumferential surface and both sides of the uncrosslinked rubber belt 1 without covering the outer circumferential surface); otherwise, it is carried out in the same way as in Examples 15-16, and a wrapped V-belt with 3 wrapped V-belt portions 1 is obtained.

[0234] [Exposed rubber on the side of the fabric-covered V-belt] We confirmed whether there were any areas on the side of the wrapped V-belt portion of the fabric-covered V-belt obtained after the bonding process (after cross-linking) where the rubber was exposed and not covered by the cover fabric. The results are shown in the table below.

[0235] [Peeling Test] The obtained fabric-covered V-belt was cut along the three fabric-covered V-belt sections (divided into 3 sections), and the peel force of the connecting strip was measured. Specifically, a 15cm segment was cut from the cut, endless loop-shaped strip along the length of the strip as a sample for the peel test. After making a cut between the connecting strip and the fabric-covered V-belt section using a knife, the connecting strip and the fabric-covered V-belt section were stretched in the direction of pull (peel angle 180°, i.e., the connecting strip was folded back 180° relative to the fabric-covered V-belt section) using an Autograph (manufactured by Shimadzu Corporation, "AGS-J10kN"), and the peel force during peeling along the length of the strip was measured. The peel force was calculated by dividing the measured tensile force by the width of the peel surface (the width of the outer circumference of the fabric-covered V-belt section (the combined width of the covered and uncovered areas) as the value per 1cm width.

[0236] In addition, the peel test sample is cut from any three points on the previously separated endless loop strip, and the arithmetic mean of the values ​​(peel force) obtained from the three samples is used. Furthermore, if the exposed rubber portion is visible on the side of the wrapped V-belt, the peel test sample is cut from any three points on the side where the rubber is not exposed (or in the area).

[0237] While it also depends on the usage conditions, if the peel force of the connecting strip is below approximately 50 N / cm, peeling is considered likely to occur. The results are shown in the table below. Figure 8 .

[0238] [Percentage of areas not covered] A 3cm segment was cut from the central portion of the V-belt portion of the fabric after the peel test (the V-belt portion obtained by peeling the connecting strip from the sample used in the peel test) along the length of the belt as an observation sample, and its peeled surface (outer peripheral surface) was observed. Specifically, the peeled surface was photographed using a microscope (Keyence Corporation "VHX-5000"), and the image was analyzed using measurement software (Olympus Corporation "Stream") to identify the uncovered and covered areas as different regions in the photographed image, and the proportion of the uncovered area was calculated based on the area ratio of each region.

[0239] For each observation sample obtained from the three peel test samples, the proportion of uncovered area was calculated, and the arithmetic mean of the values ​​(proportions of uncovered area) obtained from the three samples was used. The results are shown in the table below.

[0240] [Lateral offset change] A fabric-covered V-belt was mounted on a pair of pulleys with a diameter of 113 mm at 80°C, and an axle load of 500 N was applied. The position of the belt back side at this point was measured using a laser displacement gauge and set as the origin (0 mm). Next, the axle load was increased to 2000 N, and the change in position of the belt back side (lateral offset change) was measured. The smaller the lateral offset change, the better the lateral pressure resistance. The results are shown in the table below.

[0241] [Wear Rate] like Figure 9 As shown, a biaxial running test machine consisting of a 180mm diameter drive (Dr.) pulley and a 180mm diameter driven (Dn.) pulley was used to evaluate wear resistance. Specifically, a fabric-covered V-belt was mounted on each pulley, with an axle load of 1600N, a drive pulley speed of 1800rpm, and a driven pulley load of 53N·m. The belt was run for 96 hours at an ambient temperature of 23℃. The belt mass before and after operation was measured, and the rate of change in mass (wear rate) was evaluated using the following formula. A lower wear rate indicates better wear resistance. The results are shown in the table below.

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

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

[0244] [Durability Lifespan] like Figure 10 As shown, a triaxial running test machine equipped with a 100mm diameter drive (Dr.) pulley, a 100mm diameter driven (Dn.) pulley, and an 85mm diameter back tension (Ten.) pulley was used to evaluate the durability of the fabric-covered bundled V-belt. Specifically, the fabric-covered bundled V-belt was mounted on each pulley, and the contact angle between the belt and the back tension pulley was adjusted to 20°. A load of 588N was applied to the driven pulley, the drive pulley speed was set to 3600 rpm, and the driven pulley was left unloaded. The operating time [in hours] at an ambient temperature of 110°C until the end of the belt's life was defined as the durability life. Furthermore, the belt's life was defined as the moment when the connecting belt peeled off in a continuous section of more than 100mm along its length. The results are shown in the table below.

[0245]

[0246]

[0247] From Tables 2 to 3 and Figure 8It is evident that in any of Examples 1-6 (where the stretch rubber layer is R1), Examples 7-9, and Reference Example 1 (where the stretch rubber layer is R2), the peel force increases as the proportion of the uncovered area not covered by the cover fabric increases relative to the overall area of ​​the back side of the wrapped V-belt portion. However, if the proportion of the uncovered area exceeds 80%, areas not covered by the cover fabric appear on the side of the wrapped V-belt portion. Comparing the case with the stretch rubber layer R1 and the case with R2, the peel force is slightly higher in the case with R1.

[0248]

[0249] As can be clearly seen from Table 4, all embodiments exhibit high peel strength. Not only was no rubber exposed on the side of the wrapped V-belt section of the belt immediately after manufacturing, but also peeling of the cover fabric at the boundary between the wrapped V-belt section and the connecting belt was suppressed in the belt after operation (after wear rate and durability evaluation). Therefore, all embodiments can suppress wear rate and achieve excellent durability.

[0250] Examples 10-12 are examples where the cover fabric in Examples 4-6 is changed to two layers. Similar to Examples 4-6, the peel force increases as the proportion of the uncovered area increases. On the other hand, in Example 6 (90%), where the proportion of the uncovered area is large, a small number of areas not covered by the cover fabric (areas where rubber is exposed) were observed on the side of the wrapping V-belt portion. However, in Example 12, where the cover fabric is two layers, even if rubber is exposed on the side during the first wrapping process, the exposed area can be covered by the second wrapping process. Therefore, despite the large proportion of the uncovered area, it is possible to manufacture without exposing the rubber from the side of the wrapping V-belt portion. Furthermore, the lateral offset variation and wear rate are the same in Examples 10-12, but the durability is particularly high in Examples 11-12, where the proportion of the uncovered area is large.

[0251] Examples 13-14 are examples where the cover fabric in Example 5 is changed to 3 or 4 layers. Comparing Examples 5, 11, 13, and 14 with different numbers of cover fabric layers reveals that the wear rate is the same, but there is a tendency for the lateral offset to increase with the number of layers (the belt tends to sink towards the pulley under tension, resulting in decreased lateral pressure resistance). Examples 13-14 (especially Example 14) with 3-4 layers of cover fabric show a significant decrease in lateral pressure resistance. The reason for this is uncertain, but it is speculated that the increased number of cover fabric layers reduces the proportion of the harder belt body (the hard rubber portion). In Examples 13-14, where lateral pressure resistance decreases, when the V-belt portion sinks towards the pulley center during operation, the force tends to act in the direction of peeling from the connecting belt, thus resulting in a slight decrease in durability.

[0252] On the other hand, in Example 5, where the cover is a single layer, the lateral offset variation is minimal, and the lateral pressure resistance is excellent. The peel force and wear rate are also comparable to those of Example 11. However, Example 11, with a two-layer cover, exhibits superior durability. The reason for this is uncertain, but it is believed to be due to the following influence: Since the cover in Example 5 is only a single layer, even with the same wear rate, the rubber in the main body of the belt is easily exposed or seeps out from the worn areas of the cover. That is, it is speculated that the rubber exposure or seepage during belt operation increases the coefficient of friction with the pulley, resulting in significant heat generation, which reduces the adhesion at the bonding area with the connecting belt, making it easier to peel off from the connecting belt.

[0253] Therefore, in Example 11, where the cover is two-layered, rubber exposure or leakage can be effectively suppressed, and the lateral pressure resistance is also excellent. Among Examples 5, 11, 13, and 14, the durability is the best.

[0254]

[0255] Examples 15 and 16 are examples in Examples 11 and 12 where the proportion of the uncovered area of ​​the inner cover (second cover) is changed to 100% in the two-layer cover fabric. That is, in Examples 11 and 12, the outer cover (first cover) and the inner cover overlap each other. Figure 6 (That way) covers the main body; while in embodiments 15-16, as Figure 7 As shown, the inner cover does not cover the back of the belt; only the outer cover forms a covered area. Examples 15-16 exhibit similarly high peel strength as Examples 11-12. Furthermore, in Examples 15-16, not only was no rubber exposed on the side of the wrapped V-belt portion of the belt immediately after manufacturing, but also, after operation (after wear rate and durability evaluation), peeling of the cover at the boundary between the wrapped V-belt portion and the connecting belt was suppressed, resulting in a lower wear rate and excellent durability.

[0256] In Examples 15 and 16, as the proportion of the uncovered area formed solely by the outer cover (first cover) increases, the peel force also increases, similar to Examples 11 and 12. Furthermore, in Example 16, as in Example 12, even with a larger proportion of the uncovered area, it is possible to manufacture without exposing the rubber from the side of the V-belt portion. The lateral offset variation and wear rate are similar in Examples 15 and 16, but Example 16, with its larger proportion of the uncovered area, exhibits a higher durability.

[0257] Reference Example 2 is an example in which the proportion of the non-covered areas of both the inner cover (second cover) and the outer cover (first cover) is changed to 100%, that is, an example of manufacturing in which neither the inner nor the outer cover forms a covered area. Although Reference Example 2 exhibits high peel strength, the rubber is exposed on the side of the wrapped V-belt portion of the belt immediately after manufacturing. Furthermore, during operation (in the evaluation of wear rate and durability), the cover is prone to peeling at the boundary between the side of the wrapped V-belt portion and the connecting belt, resulting in high wear rate and short durability.

[0258] Among the embodiments, embodiments 11-12 and 15-16 are excellent in terms of the balance of adhesion, wear resistance, lateral pressure resistance, durability and productivity of the connecting strip. From the perspective of being able to meet these performances at a high level and with good balance, while further improving production efficiency (better workability in the covered process and the ability to improve the yield of finished products), embodiments 11 and 15, with an uncovered area of ​​70%, are particularly excellent. Industrial applicability

[0259] The fabric-coated V-belt of this invention can be applied to general industrial machinery such as compressors, generators, and pumps, as well as agricultural machinery such as combine harvesters, rice transplanters, and lawn mowers. Furthermore, it can also be applied to high-load machinery used in high-load, long-span configurations, such as large agricultural machinery used in Europe and America, specifically including: tillers, vegetable transplanters, transplanting and planting machines, balers, combine harvesters, vegetable harvesters, threshers, bean cutters, corn harvesters, potato harvesters, and sugar beet harvesters.

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

[0261] 1, 11, 21, 31: Fabric-covered grouped V-belts V: Covering V-belt section 2, 12, 22, 32: Compression rubber layer 3, 13, 23, 33: Core layer (core, adhesive rubber layer) 4, 14, 24, 34: Stretch rubber layer 4a, 14a, 24a, 34a: Non-covered areas 5, 15, 25, 35: Covering cloth (first covering cloth or outer covering cloth). 26, 36: Cover (second cover or inner cover) 5a, 15a, 25a, 26a, 35a: Coverage area T: Connecting strap.

Claims

1. A fabric-covered interlocking V-belt, comprising: Multiple fabric-covered V-belt sections, with the main body of the belt covered by a cover fabric; as well as A connecting strap connects the plurality of fabric-covered V-belt portions on the outer peripheral surface of each fabric-covered V-belt portion. The outer peripheral surface of the V-belt portion of the covering fabric has a covered area and an uncovered area covered by the cover fabric. The covering area is formed on at least one side of the outer peripheral surface, and the cover fabric covering the covering area also covers the side of the wrapping fabric V-belt portion.

2. The wrapped V-belt according to claim 1, wherein, The covered and uncovered areas are formed by extending along the length of the strip.

3. The wrapped V-belt according to claim 1 or 2, wherein, The covered area is formed on both sides of the outer peripheral surface.

4. The wrapped V-belt according to any one of claims 1 to 3, wherein, The area of ​​the non-covered area is 25% to 95% relative to the area of ​​the outer peripheral surface of the wrapped V-belt portion.

5. The wrapped V-belt according to any one of claims 1 to 4, wherein, The main body of the belt is covered by 1 to 3 layers of fabric.

6. The wrapped V-belt according to any one of claims 1 to 5, wherein, The main body of the belt is covered by multiple layers of fabric.

7. The wrapped V-belt according to any one of claims 1 to 6, wherein, The main body of the belt is covered with multiple layers of fabric. The outermost first cover in the multi-layered cover forms the covering area on its outer peripheral surface. One or more second covers located inside the first cover do not cover the outer perimeter.

8. The wrapped V-belt according to any one of claims 1 to 7, wherein, The connecting strip contains at least fibers.

9. A method for manufacturing a fabric-covered V-belt, as described in any one of claims 1 to 8, comprising at least: In the covering process, the main body of the belt is covered with a cover fabric precursor to form the wrapped V-belt precursor. as well as In the connecting process, the outer peripheral surfaces of the multiple fabric-covered V-belt front parts obtained in the covering process are connected using a connecting belt front part. In the covering process, the inner circumferential surface and both sides of the main body front are covered, while the cover cloth front covering the side is used to cover at least one side of the outer circumferential surface but not a portion of the outer circumferential surface.

10. The manufacturing method according to claim 9, wherein, The manufacturing method does not include the process of removing or cutting off the outer peripheral surface of the cover fabric precursor obtained in the covering process.

11. The manufacturing method according to claim 9 or 10, wherein, In the covering process, the width of the cover fabric precursor is smaller than the perimeter of the cross-sectional shape of the main body precursor perpendicular to the length direction, and the width direction of the cover fabric precursor is covered in a direction perpendicular to the length direction of the belt.

12. The manufacturing method according to any one of claims 9 to 11, wherein, In the covering process, a seamless cover fabric precursor is used to cover at least one side of the inner circumferential surface, both sides, and at least one side of the outer circumferential surface of the main body precursor.

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