Joined V-belt and manufacturing method thereof

Abstract

The present invention relates to a joined V-belt comprising two or more wrapping V-belt parts and a strapping tape, the outer peripheral surfaces of the wrapping V-belt parts being joined by the strapping tape, each wrapping V-belt part comprising a belt main body and an outer wrapping cloth covering the outer surface of the belt main body, the belt main body comprising a core layer, an extended rubber layer, and a compressed rubber layer, the strapping tape includes a short-fiber-containing rubber layer, and the short-fiber-containing rubber layer has two or more ribs.

Description

Technical Field

[0001] The present invention relates to a combined V-belt formed by connecting two or more cloth-wrapped V-belts in the width direction and a manufacturing method thereof. Background Art

[0002] As transmission belts for transmitting power, friction transmission belts such as V-belts, multi-ribbed belts, and flat belts are known. V-belts include raw-edge type (raw-edge V-belts) with the friction transmission surface exposed as a rubber layer and wrapped type (wrapped V-belts) with the friction transmission surface (V-shaped side) covered with outer cloth. These V-belts are generally widely used in general industrial machinery and agricultural machinery.

[0003] Only one V-belt is used in applications where power can be transmitted as a single unit. For example, in a high-load working environment such as the working environment of large agricultural machinery used in large-scale farms in Europe and the United States, where huge power transmission is required while repeating forward and reverse rotations on multiple axes, two or more V-belts need to be used simultaneously. That is, two or more V-belts need to be wound (multiple windings) around the pulley of the belt transmission mechanism in a parallel state and rotated to travel.

[0004] However, when multiple belts are wound, there may be a tension difference between two or more parallel V-belts, which may impair stable power transmission. In addition, due to the contact between adjacent V-belts, the inner and outer sides of the belt may be reversed to form an opposite structure, i.e., flip. In addition, in the running layout of the belt transmission mechanism used in large agricultural machinery in Europe and the United States, the distance between the axes of the pulleys on which the V-belts are wound is very long. Therefore, the V-belt is prone to large vibration during running, and may be excited if the lengths of two or more belts are inconsistent.

[0005] Therefore, in an environment where two or more V-belts are run in parallel, a combined belt (combined V-belt) is used in which two or more annular V-belt portions having the same structure as the V-belt or corresponding structure are connected in the belt width direction. The combined belt is a V-belt in which two or more belt portions are connected and combined by a binding belt (a connecting member such as cloth) in a state where two or more belt portions are arranged in parallel.

[0006] Regarding the combined V-belt, for example, in Japanese Patent Laid-Open No. 10-274290 (Patent Document 1), Figure 1 and 2 and Japanese Patent Application Publication No. 2001-241513 (Patent Document 2) Figure 2 The trimmed V-belt is disclosed in Japanese Patent Publication No. 4-351350 (Patent Document 3). Figure 1 and Japanese Patent Application Publication No. 2020-3061 (Patent Document 4) Figure 1According to these combined V-belts, the above-mentioned problems that occur when a plurality of V-belts are wound around a pulley can be eliminated, and a large power can be transmitted using two or more V-shaped protrusions.

[0007] On the other hand, in a belt transmission mechanism that uses such a combined V-belt and requires multi-axis transmission, power is sometimes transmitted not only through the inner peripheral surface of the belt but also through the outer peripheral surface (back surface) of the belt. In order to improve the transmission performance of the outer peripheral surface (back surface) in this transmission mechanism, it is preferred that a friction transmission surface having a V-shaped side surface that can contact the V-belt pulley is also provided on the outer peripheral surface side.

[0008] It should be noted that for V-belts (commonly known as hexagonal belts) capable of double-sided transmission, there are known single belts (V-belts not connected in two or more). For example, Japanese Patent Publication No. 2016-200231 (Patent Document 5) discloses a transmission belt for double-sided transmission, which has an inner peripheral side portion and an outer peripheral side portion connected to the outer peripheral side of the inner peripheral side portion, and the surface of the inner peripheral side portion and the surface of the outer peripheral side portion have different friction coefficients. Japanese Patent Publication No. 2019-32078 (Patent Document 6) discloses a jointless V-belt, wherein both the inner peripheral side surface and the outer peripheral side surface have V-shaped side surfaces that can contact the V-belt pulley, and have a hexagonal cross-section.

[0009] Prior art literature

[0010] Patent Literature

[0011] Patent Document 1: Japanese Patent Application Laid-Open No. 10-274290

[0012] Patent Document 2: Japanese Patent Application Publication No. 2001-241513

[0013] Patent Document 3: Japanese Patent Application Laid-Open No. 4-351350

[0014] Patent Document 4: Japanese Patent Application Publication No. 2020-3061

[0015] Patent Document 5: Japanese Patent Application Publication No. 2016-200231

[0016] Patent Document 6: Japanese Patent Application Publication No. 2019-32078 Summary of the invention

[0017] Problems to be solved by the invention

[0018] However, although the combined V-belts of Patent Documents 1 to 4 have been put into practical use, they cannot transmit power through the outer peripheral surface. On the other hand, the hexagonal belts of Patent Documents 5 to 6 are difficult to manufacture because two or more hexagonal belts are connected in the width direction, and have not been put into practical use. Therefore, a combined V-belt with excellent productivity and capable of double-sided transmission is required.

[0019] Therefore, an object of the present invention is to provide a coupled type combined V-belt capable of high-performance double-sided transmission and high-capacity transmission, and a method for manufacturing the same.

[0020] Methods used to solve problems

[0021] The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that by using a strapping tape comprising a short fiber-containing rubber layer in which short fibers are oriented in the belt width direction, and the short fiber-containing rubber layer having two or more ribs extending in the belt length direction as the strapping tape used in the V-belt of the present invention, a linked combined V-belt capable of high-performance double-sided transmission and high-capacity transmission can be provided, thereby completing the present invention.

[0022] That is, the combined V-belt according to the embodiment [1] of the present invention is a combined V-belt including two or more wrapped V-belt portions and a binding belt, wherein:

[0023] The outer peripheral surfaces of each V-belt portion are connected by the above-mentioned binding belt.

[0024] Each cloth-wrapped V-belt portion includes a belt body and an outer cloth covering the outer surface of the belt body.

[0025] The belt body includes a core layer including a core, a stretch rubber layer laminated on the core layer on the belt outer peripheral side, and a compression rubber layer laminated on the core layer on the belt inner peripheral side.

[0026] The strapping tape comprises a rubber layer containing short fibers, wherein the short fibers are oriented in the width direction of the tape.

[0027] The short-fiber-containing rubber layer has two or more ribs extending in the belt length direction.

[0028] Aspect [2] of the present invention is the aspect described below: In aspect [1], the arrangement pitch of the ribs is smaller than the arrangement pitch of the wrapping V-belt portions.

[0029] A third aspect of the present invention is the aspect described below: in the above aspect [1] or [2], the arrangement pitch of the ribs is larger than the width of the gap between adjacent wrapping V-belt portions.

[0030] Aspect [4] of the present invention is the aspect described below: In any one of aspects [1] to [3], the binding tape includes the short fiber-containing rubber layer and a fabric layer,

[0031] The fabric layer includes a fiber structure laminated on the inner peripheral surface of the short fiber-containing rubber layer.

[0032] Mode [5] of the present invention is a mode as described below: the fiber structure of the above-mentioned mode [4] is a cord comprising two or more first filaments extending in the belt width direction and two or more second filaments extending in a direction intersecting the belt width direction,

[0033] The arrangement density of the second filaments is smaller than the arrangement density of the first filaments.

[0034] Aspect [6] of the present invention is the aspect described below: In any one of aspects [1] to [5], the center of the top of the rib portion is located in a gap between adjacent wrapping V-belt portions.

[0035] Aspect [7] of the present invention is the aspect described below: In any one of aspects [1] to [6], the thickness of the binding band is 0.3 to 0.7 times the thickness of the wrapping V-band portion.

[0036] In the present invention, as aspect [8], there is also included a method for manufacturing a combined V-belt according to any one of aspects [1] to [7], which comprises:

[0037] A connecting step of connecting two or more cloth-wrapped V-belt precursors using a strapping belt precursor;

[0038] a cross-linking molding step of heating and pressurizing the connected wrapping V-belt precursor and the binding belt precursor to perform cross-linking molding; and

[0039] A rib forming step is a step of forming a rib on the outer peripheral side of the obtained cross-linked shaped body.

[0040] Effects of the Invention

[0041] In the present invention, as described above, a binding belt including a short fiber-containing rubber layer in which short fibers are oriented in the belt width direction and the short fiber-containing rubber layer has two or more ribs extending in the belt length direction is used, so that a linked V-belt capable of high-performance double-sided transmission and high-capacity transmission can be provided. In addition, such a linked V-belt can be easily manufactured by a manufacturing method in which two or more wrapping V-belt precursors are linked by a binding belt precursor and ribs are formed on the outer periphery after cross-linking and molding. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1This is a schematic partially cutaway perspective view showing an example of a cut-away combined V-belt of the present invention.

[0043] Figure 2 This is a schematic partially cutaway perspective view showing another example of a cut-away combined V-belt of the present invention.

[0044] Figure 3 This is a schematic partially cutaway perspective view showing still another example of a cut-away combined V-belt according to the present invention.

[0045] Figure 4 This is a schematic partially cutaway perspective view showing still another example of a cut-away combined V-belt according to the present invention.

[0046] Figure 5 It is used to illustrate the Figure 2 A schematic cross-sectional view of the structure and dimensions of a combined V-belt.

[0047] Figure 6 This is a schematic cross-sectional view of an example of a cover V-belt portion constituting the combined V-belt of the present invention.

[0048] Figure 7 It is a schematic cross-sectional view of another example of the wrapped V-belt portion constituting the combined V-belt of the present invention.

[0049] Figure 8 This is a schematic overall view showing the process of connecting and cross-linking a combined V-belt precursor.

[0050] Fig. 9 This is a schematic cross-sectional view showing a state where the wrapping V-belt precursor and the binding band precursor are fitted into a pressing die.

[0051] Fig.10 This is a schematic cross-sectional view showing a rib forming step of forming a rib on the outer peripheral side of a cross-linked molded body.

[0052] Fig.11 1 is a diagram showing a multi-axis layout of a configuration for a belt travel test as an embodiment. DETAILED DESCRIPTION

[0053] The combined V-belt of the present invention comprises two or more cloth-wrapped V-belt portions arranged in the belt width direction and a binding belt (joining member) for connecting the outer peripheral surfaces of the two or more cloth-wrapped V-belt portions. The binding belt has a short fiber-containing rubber layer (cross-linked rubber composition) in which short fibers are arranged (oriented) in the belt width direction. Two or more ribs extending in the belt length direction are formed on the belt outer peripheral side of the short fiber-containing rubber. The cloth-wrapped V-belt portion may have the same structure as a conventional cloth-wrapped combined V-belt.

[0054] Hereinafter, the combined V-belt of the present invention will be described in detail with reference to the drawings as needed.

[0055] In addition, in the following description, the same reference numerals may be used to indicate the same elements (or members) or those having the same functions.

[0056] exist Figure 1 An example of a combined V-belt of the present invention is shown in FIG. Figure 1 As shown, the combined V-belt 1 (embodiment 1) includes two cloth-wrapped V-belt portions 2 arranged in parallel with a gap. The outer peripheral surfaces of the two cloth-wrapped V-belt portions 2 are connected by a binding belt (connecting member) 7 having two or more ribs 7a extending in the belt length direction (circumferential direction, A direction in the figure). The binding belt 7 is formed of a cross-linked rubber composition (short fiber-containing rubber layer) containing short fibers 7b oriented in the belt width direction (B direction in the figure).

[0057] The cross-sectional shape of the rib 7a in the belt width direction is an inverted V-shape (trapezoidal shape). In the combined V-belt 1, two or more ribs 7a having such a cross-sectional shape are formed in parallel in the belt width direction, and a V-shaped groove is formed between adjacent ribs 7a. On the outer peripheral surface of the binding belt 7, the V-belt pulley (V-rib pulley) contacts the V-shaped groove formed at intervals. The bottom of the V-shaped groove of the rib 7a is located in the gap (connecting portion) between the adjacent wrapped V-belt parts 2.

[0058] Each cloth-wrapped V-belt portion 2 is formed by a belt body and an outer cloth 6 (woven fabric, knitted fabric, non-woven fabric, etc.). The above-mentioned belt body is formed by an extended rubber layer 3 on the outer peripheral side of the belt, a compressed rubber layer 5 on the inner peripheral side of the belt, and a core layer 4 between the above-mentioned extended rubber layer 3 and the compressed rubber layer 5. The above-mentioned outer cloth 6 covers the periphery of the above-mentioned belt body over the entire length of the belt circumference. That is, the above-mentioned outer cloth 6 covers the outer surface of the above-mentioned belt body. The core 4a extending along the length direction of the belt is buried in the above-mentioned core layer 4. In this example, the core 4a is a core wire (twisted rope) arranged at a specified interval in the belt width direction (direction B in the figure).

[0059] Figure 2 The combined V-belt (embodiment 2) shown in the figure is similar to the embodiment 1 except that the binding belt is formed of a laminate of a rubber layer containing short fibers having two or more ribs and a fabric layer laminated on the inner peripheral side of the rubber layer containing short fibers. Figure 1The present invention relates to a combined V-belt of the same type as the combined V-belt of the above-mentioned combined V-belt 11. That is, in the above-mentioned combined V-belt 11, the outer peripheral surfaces of the cloth V-belt portion 12 covered with the outer covering cloth 16 around the endless belt body formed by the extension rubber layer 13, the core layer 14 in which the core 14a is embedded, and the compression rubber layer 15 are connected by the binding belt 17. The above-mentioned binding belt 17 is formed by a cloth layer 18 in contact with the outer peripheral surface of the cloth V-belt portion 12 and a rubber layer 19 containing short fibers. The above-mentioned rubber layer 19 containing short fibers is laminated on the outer peripheral surface of the above-mentioned cloth layer 18, has two or more ribs 19a, and is formed of a cross-linked rubber composition containing short fibers 19b oriented in the belt width direction. The above-mentioned cloth layer 18 includes cords formed of warp yarns 18a and weft yarns 18b. In this combined V-belt, by making the binding belt have a cloth layer, it is possible to suppress ring breakage (longitudinal cracking) at the connecting portion between adjacent cloth V-belt portions.

[0060] Figure 3 The combined V-belt (embodiment 3) shown in the figure is different from the embodiment 1 except that the structure of the V-rib of the strapping belt is different. Figure 1 That is, in the combined V-belt 21, the outer peripheral surfaces of the wrapped V-belt portion 22 covered with an outer covering cloth 26 are connected by a binding belt 27. The binding belt 27 is connected to the outer covering cloth 26. Figure 1 Similarly, it has two or more ribs 27a extending in the belt length direction and is formed of a cross-linked rubber composition (short fiber-containing rubber layer) containing short fibers 27b oriented in the belt width direction. Figure 1 In contrast, the top center of the rib 27a is located in the gap between the adjacent wrap V-belt parts 22. In this combined V-belt, the top center of the rib is located in the gap (connecting part) between the adjacent wrap V-belt parts, which can suppress the ring breakage.

[0061] Figure 4 The combined V-belt (embodiment 4) shown in the figure is different from the embodiment 1 except that the structure of the V-rib of the strapping belt is different. Figure 2 That is, in the combined V-belt 31, the outer peripheral surfaces of the wrapped V-belt portion 32 covered with an outer covering cloth 36 are connected by a binding belt 37. The binding belt 37 is connected to the outer covering cloth 36. Figure 2The binding belt 37 is similarly connected to the outer peripheral surface of the wrapped V-belt portion 32. The above-mentioned binding belt 37 is formed by a cloth layer 38 and a rubber layer 39 containing short fibers. The above-mentioned cloth layer 38 includes cords formed by warp yarns 38a and weft yarns 38b. The above-mentioned rubber layer 39 containing short fibers is laminated on the outer peripheral surface of the above-mentioned cloth layer 38, has two or more ribs 39a, and is formed of a cross-linked rubber composition containing short fibers 39b oriented in the belt width direction. However, unlike Figure 2 Differently, the top center of the rib 38a is Figure 3 Similarly, it is located in the gap (connecting portion) between the adjacent wrapped V-belt portions 32. In this combined V-belt, by making the binding belt have a cloth layer and forming the structure of the rib portion so that the top center of the rib portion is located in the gap (connecting portion) between the adjacent wrapped V-belt portions, it is possible to highly suppress loop breakage.

[0062] The number of roots of the cloth-wrapped V-belt portion is not limited to Figures 1 to 4 The two shown in the figure may be more than two, for example, 2 to 10, preferably 2 to 8, and more preferably 2 to 6. Adjacent V-belt portions of the wrapping cloth may be arranged parallel to each other in the length direction, and are not limited to the following. Figures 1 to 4 The arrangement with intervals shown above may also be arranged without intervals. From the perspective of productivity, etc., it is preferred that adjacent wrapper V-belt portions are arranged with intervals.

[0063] use Figure 5 , the structure and dimensions of the combined V-belt of the present invention are explained. Figure 5 is with Figure 2 Same schematic cross-section view. Figure 5 In the figure, each symbol is defined as follows. H represents the belt thickness (the thickness of the combined V-belt). H1 represents the thickness of the cloth V-belt portion. H2 represents the height of the rib on the back of the belt. H3 represents the thickness of the strapping belt (T) (the thickness of the maximum thickness portion). d represents the thickness of the base (minimum thickness portion) of the strapping belt (T). W represents the belt width (the width of the combined V-belt). W1 represents the width (upper width) of the cloth V-belt portion. P1 represents the arrangement pitch of the cloth V-belt portion (the distance between the centers of adjacent cloth V-belt portions in the belt width direction). P2 represents the arrangement pitch of the ribs (the distance between the centers of adjacent ribs in the belt width direction, that is, the distance between the adjacent rib peaks 19c sandwiching the rib valley portion 19d). e represents the width of the connecting portion (the interval or gap between adjacent cloth V-belt portions).

[0064] When adjacent V-belt wrapping parts are arranged at intervals, the interval (width of the connecting part) (e) between adjacent V-belt wrapping parts is the dimension value obtained by subtracting the upper width (W1) of each V-belt wrapping part from the arrangement pitch (P1) of each V-belt wrapping part, and is, for example, 1.3 to 3.0 mm. Figures 1 to 4As shown in the figure, the entire surface of the outer peripheral surface of each wrapper V-belt portion is contacted and integrated with each wrapper V-belt portion, thereby connecting two or more wrapper V-belt portions.

[0065] for Figure 5 The dimensions shown in Table 1 are the dimensions of Type A, Type B and Type C, which are representative examples of the combined V-belt of the present invention. In Table 1, the dimensions in parentheses represent the maximum values ​​of the dimensions required when the strapping belt does not further have a fabric layer containing a fiber structure [that is, when the strapping belt is formed only of a rubber layer containing short fibers (Embodiments 1 and 3)]. In addition, in the present application, the numerical values ​​in Table 1 are merely representative examples, and the dimensions are not limited to these numerical values.

[0066] [Table 1]

[0067]

[0068] If the balance between high rigidity (resistance to lateral pressure) in the belt width direction and bending property toward the inner circumference of the belt is considered, the thickness (H3) of the strapping belt is preferably smaller than the thickness (H1) of the V-belt portion of the wrapping cloth, although it also depends on the internal structure of the strapping belt and the position of the core layer in the belt thickness direction.

[0069] The ratio (H3 / H1) of the thickness (H3) of the strapping band to the thickness (H1) of the V-belt portion of the wrapping cloth can be selected from a range of about 0.25 to about 0.75, for example, 0.3 to 0.7, preferably 0.3 to 0.6, more preferably 0.4 to 0.6, more preferably 0.4 to 0.5, and most preferably 0.42 to 0.48. The thickness of the strapping band is particularly preferably about half the thickness of the V-belt portion of the wrapping cloth. If H3 / H1 is too small, the transmission performance may be reduced. On the contrary, if H3 / H1 is too large, the durability may be reduced.

[0070] On the other hand, from the perspective of ensuring the bending property toward the outer peripheral side of the belt (the reverse bending property of the belt), although it also depends on the internal structure of each wrapped V-belt part (especially the position of the core layer in the belt thickness direction), a thin V-belt with a smaller ratio (H1 / W) of the V-belt part thickness (H1) to the upper width (W) is preferred (H1 / W is, for example, 0.5 to 0.7). Among such thin V-belts, the belt types (representative examples) suitable for general V-belt pulleys (V-rib pulleys) are Type A, Type B, and Type C.

[0071] The combined V-belt of the present invention is characterized in that, by providing the binding belt on the outer peripheral side (back side) of the belt with specific ribs extending in the belt length direction, high-capacity and high-efficiency transmission can be performed even on the back side. Therefore, if the contact area of ​​the cross-sectional V-shaped groove that can contact the V-shaped side surface (friction transmission surface) of the back driven pulley (V-rib pulley) is increased, high-capacity and high-efficiency transmission can be performed on the outer peripheral surface of the belt. However, if the contact area is increased, sometimes the lateral pressure resistance is insufficient and cracks are easily introduced, resulting in reduced durability. Therefore, in order to achieve a balance between the two characteristics, it is important to design the ribs on the back side of the belt.

[0072] The rib height (H2) on the belt back surface is, for example, 0.5 to 10 mm, preferably 0.7 to 6 mm, more preferably 1 to 5 mm, more preferably 1.5 to 4 mm, and most preferably 2 to 3 mm.

[0073] The arrangement pitch (P2) of the ribs on the belt back surface is, for example, 1.5 to 19 mm, preferably 2 to 13 mm, more preferably 3 to 10 mm, more preferably 3.5 to 7 mm, and most preferably 3.8 to 5 mm.

[0074] In addition, if the aspects of lateral pressure resistance and bending resistance are taken into consideration, as well as the aspects of ensuring the transmission performance of the back side of the belt (the contact area and wedge effect of the friction transmission surface on the outer peripheral side of the belt with the back driven pulley) and suppressing ring breakage are taken into consideration, the arrangement spacing (P2) of the ribs is preferably smaller than the arrangement spacing (P1) of the wrapped V-belt part. In addition, the arrangement spacing (P2) of the ribs is preferably larger than the width (e) of the connecting part, that is, the width of the gap between adjacent wrapped V-belt parts. The ribs are formed in such a way that the volume (cross-sectional area) becomes larger as the size (belt shape) of the combined V-belt increases to type A, type B and type C (the larger the transmission capacity). It is necessary to appropriately set the ratio of the rib height (H2) to the thickness (H1) of the wrapped V-belt part, and the ratio (P1 / P2) of the arrangement spacing (P1) of the wrapped V-belt part to the arrangement spacing (P2) of the ribs, so as to achieve a balanced shape overall.

[0075] As the length ratio in the belt thickness direction, the ratio (H2 / H1) of the rib height (H2) to the thickness (H1) of the V-belt portion of the wrap is, for example, 0.1 to 0.5 (for example, 0.15 to 0.35), preferably 0.12 to 0.4 (for example, 0.19 to 0.33), further preferably 0.21 to 0.32, and more preferably 0.25 to 0.3. If the ratio H2 / H1 is too small, the transmission performance of the back side of the belt may be reduced. On the contrary, if the ratio H2 / H1 is too large, the bending resistance may be reduced.

[0076] The arrangement pitch ratio (P1 / P2) of the wrap V-belt portion relative to the rib portion can be selected from a range of about 1 to about 8 (particularly about 1.5 to about 7). In view of productivity, the ratio P1 / P2 is preferably an integer, for example, 2 to 6, preferably an integer of 3 to 5, more preferably 3.5 to 4.5, and more preferably 4. If P1 / P2 is too small, the transmission performance of the belt back side may be reduced, and conversely, if P1 / P2 is too large, the lateral pressure resistance may be reduced.

[0077] The thickness (H1) of the wrapped V-belt is, for example, 4 to 20 mm, preferably 5 to 15 mm, more preferably 6 to 12 mm, more preferably 7 to 10 mm, and most preferably 8 to 9 mm.

[0078] The thickness (H3) of the binding band is, for example, 2 to 10 mm, preferably 2.5 to 7 mm, more preferably 3 to 6 mm, more preferably 3.5 to 5 mm, and most preferably 3.8 to 4.7 mm.

[0079] The cross-sectional shape of the two or more ribs is not particularly limited as long as it is formed into an inverted V-shaped (trapezoidal) cross-section with no joint by two or more cross-sectional V-shaped grooves extending in the belt length direction at intervals in the belt width direction, and can be formed arbitrarily. The left and right side surfaces (inverted V-shaped side surfaces) of the inverted V-shaped (trapezoidal) cross-section are friction transmission surfaces.

[0080] In the back driven pulley driven via the friction transmission surface, the outer peripheral portion opposite to the two or more ribs on the back of the belt is a V-shaped (inverted trapezoidal) cross section formed into a jointless shape by two or more V-shaped protrusions extending in the circumferential direction at intervals in the pulley width direction. The back driven pulley is a pulley (referred to as a "V-rib pulley" in this application) configured in such a way that the left and right side surfaces (V-shaped side surfaces) of the above-mentioned V-shaped (inverted trapezoidal) cross section become friction transmission surfaces in contact with the belt.

[0081] <Cloth-wrapped V-belt>

[0082] The cloth-wrapped V-belt portion (hereinafter also referred to as "V-belt portion") connected to the binding belt (connecting member) is not particularly limited. Figures 1 to 4The V-belt portion shown in the figure is a conventional V-belt portion, that is, a V-belt portion that includes a core layer (adhesive rubber layer) containing a core (core wire), an extended rubber layer laminated on the outer peripheral side of the belt of the core layer, and a compressed rubber layer laminated on the inner peripheral side of the belt of the core layer, and a jointless V-belt portion having a V-shaped cross-section. It should be noted that the left and right side surfaces (V-shaped side surfaces) of the above-mentioned V-shaped cross-section are friction transmission surfaces. In addition, in the V-shaped cross-section, the side with a wider bandwidth is used as the outer peripheral side, and the side with a narrower bandwidth is used as the inner peripheral side. The V angle (α1) of the V-shaped side surface relative to the belt thickness direction is, for example, 35 to 45°, preferably 36 to 44°, further preferably 37 to 43°, more preferably 38 to 42°, and most preferably 39 to 41° (especially 40°).

[0083] The conventional wrapped V-belt portion is not particularly limited as long as it is a wrapped V-belt portion in which the V-shaped cross section is covered with an outer covering (covering cloth) over the entire length in the belt circumferential direction including the friction transmission surface.

[0084] In applications such as agricultural machinery, the belt and the transmission mechanism as a whole are easily damaged due to stress or impact caused by the high friction coefficient of the transmission surface, the involvement of stalks, stones, wood, etc. Therefore, as a V-belt portion, a cloth-wrapped V-belt with a small friction coefficient of the transmission surface and the ability to alleviate stress or impact with moderate slippage is often used. In such high-load applications, in order to prevent buckling deformation (concave bending), high rigidity (resistance to lateral pressure) in the belt width direction is also required. Therefore, as a V-belt portion, for example, a cloth-wrapped V-belt portion with excellent lateral pressure resistance described in Japanese Patent Gazette No. 2020-3061 (Patent Document 4), that is, a cloth-wrapped V-belt portion in which the compression rubber layer has a laminated structure including two compression rubber layers with different rubber hardnesses and the rubber hardness of each layer is adjusted, etc. If a V-belt portion with excellent lateral pressure resistance is combined with the above-mentioned strapping belt, the ring break (longitudinal crack) suppression effect can be further improved.

[0085] In detail, Figure 6 2 is a schematic cross-sectional view of an example of a V-belt portion constituting the combined V-belt of the present invention (a view in which the binding band is omitted and only the V-belt portion is shown in close-up). Figure 6 The cloth-wrapped V-belt portion 41 shown is formed from the outer circumference of the belt by an extended rubber layer 43, a core layer (adhesive rubber layer) 44 in which a core 44a is embedded in a cross-linked rubber composition, an endless belt body in which a first compression rubber layer 45a and a second compression rubber layer 45b are sequentially laminated, and an outer cloth 46 (woven fabric, knitted fabric, non-woven fabric, etc.) covering the belt body over the entire length of the belt circumference. It should be noted that, as described later, Figure 7 As in the illustrated covered V-belt portion, a reinforcing cloth layer may be further included between the inner peripheral surface (the surface on the inner peripheral side) of the compression rubber layer and the outer covering.

[0086] In these examples, the core is a core wire (twisted rope) arranged at a specified interval in the belt width direction. In addition, the core layer is formed by a cross-linked rubber composition (adhesive rubber layer) in which a core is embedded. The core layer only needs to include the core, or it can be formed only by the core disposed at the interface between the extension rubber layer and the compression rubber layer. In the present application, in the case where the core layer is formed only by the core, the core disposed at intervals in the belt body is referred to as the core layer. Such a core layer is not only a form in which a core is disposed at the interface between the extension rubber layer and the compression rubber layer, but also includes a form in which a part or all of the core disposed at the interface between the extension rubber layer and the compression rubber layer is embedded in the extension rubber layer or the compression rubber layer during the manufacturing process.

[0087] [Compression rubber layer and extension rubber layer]

[0088] The compression rubber layer constituting each V-belt portion may be as follows: Figures 1 to 4 The single layer (one layer) shown can also be as Figure 6 The rubber layer shown has a laminated structure including two rubber layers, and the rubber hardness and strength of each layer are adjusted.

[0089] Among these, from the aspect of balancing the lateral pressure resistance and the bending property, the V-belt portion preferably has a laminated structure in which the compression rubber layer has two or more layers including a first compression rubber layer laminated on the core layer side and a second compression rubber layer having a lower rubber hardness than the first compression rubber layer and laminated on the inner circumference side of the belt. It should be noted that regarding the laminated structure, the compression rubber layer and the extension rubber layer do not need to be set to the same structure, and may be different structures.

[0090] In consideration of the balance between lateral pressure resistance and productivity, it is particularly preferred that the compression rubber layer has a two-layer structure (a first compression rubber layer and a second compression rubber layer) and the extension rubber layer has a single-layer structure.

[0091] (Single-layer structure)

[0092] When the stretch rubber layer is a single-layer structure, the rubber hardness Hs of the compression rubber layer and the stretch rubber layer can be selected from a range of about 60° to about 90°, preferably 72° to 80°, more preferably 73° to 78°, further preferably 74° to 78°, and most preferably 75° to 77°. If the rubber hardness is too small, the lateral pressure resistance may be reduced. On the contrary, if the rubber hardness is too large, the bending property may be reduced.

[0093] It should be noted that in the present application, the rubber hardness of each rubber layer is a value Hs (type A) measured by using a type A durometer in a spring type Shore hardness test specified in JIS K6253 (2012) (vulcanized rubber and thermoplastic rubber - Method for determining hardness). The rubber hardness of each rubber layer is sometimes referred to as rubber hardness. In detail, the rubber hardness of each rubber layer can be measured by the method described in the examples described later.

[0094] The tensile strength of the compression rubber layer and the extension rubber layer in the belt width direction is, for example, 12 to 20 MPa, preferably 13 to 18 MPa, and more preferably 14 to 17 MPa. If the tensile strength is too low, the lateral pressure resistance may be reduced. On the contrary, if the tensile strength is too high, the bending property may be reduced.

[0095] In the present application, the tensile strength of each rubber layer is a value of the tensile strength T of each rubber layer that can be measured by a method in accordance with JIS K6251 (2017). Specifically, the tensile strength of each rubber layer can be measured by the method described in the examples described below.

[0096] (Double-layer structure)

[0097] In order to improve the lateral pressure resistance, when the compression rubber layer is a double-layer structure, it is preferred that the first compression rubber layer and the extension rubber layer arranged on the core layer side are high-hardness rubber layers. The rubber hardness Hs of the first compression rubber layer and the extension rubber layer can be selected from a range of, for example, about 80° to about 100°, preferably 85 to 95°, more preferably 87 to 94°, further preferably 90 to 93°, and most preferably 92 to 93°. If the rubber hardness is too small, the lateral pressure resistance may be reduced. On the contrary, if the rubber hardness is too large, the fit and bendability with the pulley groove may be reduced.

[0098] On the other hand, the rubber hardness Hs of the second compression rubber layer may be approximately the same as the rubber hardness Hs shown in the case where the compression rubber layer has a single-layer structure.

[0099] In addition, the difference in rubber hardness Hs between the first compression rubber layer and the second compression rubber layer [(rubber hardness of the first compression rubber layer) - (rubber hardness of the second compression rubber layer)] may be, for example, 1° or more (particularly 5° or more), preferably 5 to 30° (for example 7 to 27°), more preferably 10 to 25° (for example 12 to 20°), further preferably 14 to 20° (for example 15 to 19°), and most preferably 14 to 18° (particularly 15 to 17°). If the difference in rubber hardness Hs is too small, the bendability may be reduced.

[0100] The tensile strength of the first compression rubber layer in the belt width direction is, for example, 25 to 50 MPa, preferably 25 to 40 MPa, more preferably 26 to 35 MPa, and most preferably 28 to 32 MPa. If the tensile strength is too low, the lateral pressure resistance may be reduced. On the contrary, if the tensile strength is too high, the bending property may be reduced. The tensile strength of the second compression rubber layer can be the same as the tensile strength shown in the case where the compression rubber layer is a single-layer structure.

[0101] It should be noted that the tensile strength of the extension rubber layer can be selected from the same range including a preferred range corresponding to the tensile strength of the compression rubber layer.

[0102] The average thickness of the first compression rubber layer ( Figure 6 L2 in the figure) relative to the average thickness of the entire compression rubber layer ( Figure 6 The ratio (L1) in the formula (L2 / L1) can be selected from a range of about 95% to about 30%, preferably 90% to 50%, more preferably 85% to 55%, further preferably 80% to 60%, and more preferably 75% to 70%. The ratio (L2 / L1) can be a ratio when the compression rubber layer is composed of only the first compression rubber layer and the second compression rubber layer (in the case of a double-layer structure). If the ratio (L2 / L1) is too small, the lateral pressure resistance may be reduced. On the contrary, when the ratio (L2 / L1) is too large, the bending property may be reduced.

[0103] (Other rubber layers in the compression rubber layer)

[0104] The compression rubber layer may include other rubber layers having different rubber hardnesses in addition to the first compression rubber layer and the second compression rubber layer. The other rubber layer may be a single layer or may be two or more layers. In addition, the other rubber layer may be laminated on any of the upper and lower surfaces of the first compression rubber layer and the lower surface of the second compression rubber layer. The average thickness of the other rubber layers (the total thickness when there are two or more other rubber layers) relative to the average thickness of the entire compression rubber layer may be, for example, 30% or less, preferably 10% or less, and more preferably 5% or less. That is, the compression rubber layer preferably includes the first compression rubber layer and the second compression rubber layer as main layers. The total average thickness of the first compression rubber layer and the second compression rubber layer relative to the average thickness of the entire compression rubber layer may be, for example, 70% or more, preferably 90% or more, and more preferably 95% or more. It is particularly preferred that the compression rubber layer consists only of the first compression rubber layer and the second compression rubber layer.

[0105] (Thickness of the compression rubber layer as a whole and the extension rubber layer)

[0106] The average thickness of the entire compression rubber layer is, for example, 1 to 12 mm, preferably 2 to 10 mm, more preferably 2.5 to 9 mm, and further preferably 3 to 8 mm. The average thickness of the entire extension rubber layer is, for example, 0.5 to 10 mm (for example, 0.5 to 1.5 mm), preferably 0.6 to 5 mm (for example, 0.7 to 1 mm).

[0107] (Crosslinked rubber composition of compression rubber layer and extension rubber layer)

[0108] The compression rubber layer and the extension rubber layer can be formed of a cross-linked rubber composition commonly used as a rubber composition for a covered V-belt. The cross-linked rubber composition can be a cross-linked rubber composition containing a rubber component. By appropriately adjusting the composition of the composition, the rubber hardness of each layer constituting the compression rubber layer and the extension rubber layer, especially the first compression rubber layer and the second compression rubber layer, can be adjusted. There is no particular limitation on the method for adjusting the rubber hardness, etc. The rubber hardness can be adjusted by changing the composition and / or type of the components constituting the composition. From the perspective of simplicity, it is preferred to adjust the rubber hardness by changing the ratio and / or type of short fibers and fillers.

[0109] (A) Rubber component

[0110] The rubber component (A) contained in the cross-linked rubber composition as the compression rubber layer and the extension rubber layer can be selected from known vulcanizable or cross-linkable rubbers and / or elastomers. As the rubber component (A), for example, diene rubber [natural rubber, isoprene rubber, butadiene rubber, chloroprene rubber (CR), styrene-butadiene rubber (SBR), vinylpyridine-styrene-butadiene copolymer rubber, acrylonitrile-butadiene rubber (nitrile rubber); hydrogenated products of the above diene rubbers such as hydrogenated nitrile rubber (including a mixed polymer of hydrogenated nitrile rubber and an unsaturated carboxylic acid metal salt)], olefin rubber [such as ethylene-α-olefin rubber (ethylene-α-olefin elastomer), polyoctene rubber, ethylene-vinyl acetate copolymer rubber, chlorosulfonated polyethylene rubber, alkylated chlorosulfonated polyethylene rubber, etc.], epichlorohydrin rubber, acrylic rubber, silicone rubber, urethane rubber, fluororubber, etc. These rubber components can be used alone or in combination of two or more.

[0111] Among these, from the aspect that the crosslinking agent and the crosslinking accelerator are easily diffused, general-purpose ethylene-α-olefin elastomers [ethylene-propylene copolymer (EPM), ethylene-propylene-diene terpolymer (EPDM) and other ethylene-α-olefin rubbers] and chloroprene rubber are used. In particular, when the rubber component (A) is used in a high-load environment, from the aspect of excellent balance of mechanical strength, weather resistance, heat resistance, cold resistance, oil resistance, adhesion, etc., chloroprene rubber and EPDM are preferred. In addition, from the aspect that the wear resistance is also excellent in addition to the above characteristics, chloroprene rubber is particularly preferred. Chloroprene rubber can be a sulfur-modified type or a non-sulfur-modified type.

[0112] When the rubber component (A) contains chloroprene rubber, the proportion of the chloroprene rubber in the rubber component (A) may be, for example, 50% by mass or more (particularly about 80% to 100% by mass), and particularly preferably 100% by mass (chloroprene rubber alone).

[0113] (B) Short fibers

[0114] In addition to the rubber component (A), the crosslinked rubber composition may further contain short fibers (B). Examples of fibers constituting the short fibers (B) include polyolefin fibers (e.g., polyethylene fibers, polypropylene fibers, etc.), polyamide fibers [e.g., aliphatic polyamide fibers (nylon fibers) such as polyamide 6 fibers, polyamide 66 fibers, and polyamide 46 fibers, aramid fibers, etc.], polyalkylene arylate fibers [e.g., polyethylene terephthalate (PET) fibers, polypropylene terephthalate (PTT) fibers, polybutylene terephthalate (PBT) fibers, polyethylene naphthalate (PEN) fibers, etc.] 2-4 Alkylene C 8-14 Aromatic ester fibers, etc.], vinyl alcohol fibers (polyvinyl alcohol fibers, ethylene-vinyl alcohol copolymer fibers, vinylon fibers, etc.), polyparaphenylene benzodione Synthetic fibers such as polybutylene sulfide (PBO) fibers; cellulose fibers (cellulose fibers such as cotton and linen, fibers of cellulose derivatives, etc.), natural or semi-synthetic fibers such as wool; inorganic fibers such as carbon fibers, etc. These short fibers can be used alone or in combination of two or more.

[0115] Among these short fibers, general synthetic fibers, natural fibers, especially ethylene terephthalate, ethylene-2,6-naphthalate, etc. are C 2-4 Alkylene C 8-14Synthetic fibers such as polyester fibers (polyalkylene arylate fibers), polyamide fibers (aramid fibers, etc.), cellulose fibers such as cotton fibers, and inorganic fibers such as carbon fibers, etc., with aromatic esters as the main structural units. Among them, fibers that are rigid and have high strength and modulus, such as polyester fibers (especially polyethylene terephthalate fibers, polyethylene naphthalate fibers), polyamide fibers (especially aramid fibers), and cellulose fibers (especially cotton fibers) are preferred. Aramid fibers also have high wear resistance. Therefore, the staple fibers preferably contain at least fully aromatic polyamide fibers such as aramid fibers. The proportion of aramid fibers in the staple fibers can be 1% by mass or more (for example, 5 to 100% by mass). Aramid fibers can be commercially available products under the trade names of "Conex", "Nomex", "Kevlar (registered trademark)", "Technora", and "Twaron (registered trademark)".

[0116] The average fiber diameter of the short fibers (B) is, for example, 2 μm or more, preferably 2 to 100 μm, more preferably 3 to 50 μm (e.g., 5 to 50 μm), further preferably 7 to 40 μm, and further preferably 10 to 30 μm. The average length of the short fibers is, for example, 1 to 20 mm, preferably 1.5 to 10 mm, further preferably 2 to 5 mm, and further preferably 2.5 to 4 mm.

[0117] In the present application, the average fiber diameter and average length of the short fibers (B) can be determined, for example, by measuring the fiber diameter and length of 10 randomly selected short fibers using a scanning electron microscope or the like and calculating the arithmetic mean.

[0118] From the perspective of the dispersibility and adhesion of the short fibers (B) in the above-mentioned cross-linked rubber composition, the short fibers (B) can be subjected to bonding treatment (or surface treatment) by conventional methods. As a method for surface treatment, a method of treating with a treatment liquid containing a conventional surface treatment agent can be cited. As a surface treatment agent, for example: an RFL liquid containing resorcinol (R), formaldehyde (F) and rubber or latex (L) [for example, resorcinol (R) and formaldehyde (F) form a condensate (RF condensate), as the above-mentioned rubber or latex (L), for example, an RFL liquid containing vinylpyridine-styrene-butadiene copolymer rubber], epoxy compounds, polyisocyanate compounds, silane coupling agents, cross-linked rubber compositions (for example, cross-linked rubber compositions containing surface silanol groups and containing wet-process white carbon black as the main component of hydrous silica that is beneficial to improving the chemical bonding force with rubber, etc.) can be cited. These surface treatment agents can be used alone or in combination of two or more, and the short fibers can also be treated multiple times with the same or different surface treatment agents.

[0119] In order to suppress the compressive deformation of the belt due to the pressure from the pulley, the short fibers (B) may be oriented in the belt width direction and embedded in the compression rubber layer and / or the extension rubber layer.

[0120] The ratio of the short fibers (B) can be selected from a range of about 50 parts by mass or less, for example, 30 parts by mass or less, preferably 10 to 30 parts by mass, relative to 100 parts by mass of the rubber component (A). If the ratio of the short fibers (B) is too high, the rubber hardness may be too high and the bendability may be reduced.

[0121] In the case where the compression rubber layer has a double-layer structure, in the first compression rubber layer, the ratio of the short fibers is, for example, 5 to 50 parts by mass, preferably 10 to 30 parts by mass, more preferably 15 to 25 parts by mass, and more preferably 18 to 22 parts by mass relative to 100 parts by mass of the rubber component (first rubber component). In the second compression rubber layer, the ratio of the short fibers is, for example, 30 parts by mass or less, preferably 20 parts by mass or less, and more preferably 10 parts by mass or less relative to 100 parts by mass of the rubber component (second rubber component). In the case where the compression rubber layer has a single layer, the ratio of the short fibers in the extension rubber layer may be the same as the ratio of the short fibers in the compression rubber layer. In the case where the compression rubber layer has a double-layer structure, the ratio of the short fibers in the extension rubber layer may be the same as the ratio of the short fibers in the first compression rubber layer.

[0122] (C) Filling

[0123] In addition to the above-mentioned rubber component (A), the above-mentioned cross-linked rubber composition may also contain a filler (C). Examples of fillers include carbon black, silica, clay, calcium carbonate, talc, mica, and the like. Fillers in most cases include reinforcing fillers, and such reinforcing fillers may be carbon black, reinforcing silica, and the like. It should be noted that, in general, the reinforcing property of silica is less than that of carbon black. These fillers may be used alone or in combination of two or more. In the present disclosure, in order to improve the lateral pressure resistance, it is preferred to include a reinforcing filler, and it is particularly preferred to include carbon black.

[0124] The average particle size (number average primary particle size) of carbon black is, for example, 5 to 200 nm, preferably 10 to 150 nm, and more preferably 15 to 100 nm. From the perspective of high reinforcing effect, carbon black can be of small particle size, and the average particle size of carbon black is, for example, 5 to 38 nm, preferably 10 to 35 nm, and more preferably 15 to 30 nm. Examples of small particle size carbon black include SAF, ISAF-HM, ISAF-LM, HAF-LS, HAF, HAF-HS, etc. SAF, ISAF, and HAF are classifications of conventional carbon black, all of which are equivalent to small particle size carbon blacks called hard carbon. Specifically, the average particle size of SAF is 19 nm, the average particle size of ISAF is 22 nm, and the average particle size of HAF is 28 nm. These carbon blacks can be used alone or in combination of two or more.

[0125] In the present application, the average particle size of carbon black can be determined by, for example, measuring the particle sizes of 10 randomly selected primary particles using a transmission electron microscope or the like and calculating the arithmetic mean value.

[0126] The proportion of the filler (C) (particularly carbon black) is, for example, 10 to 100 parts by mass, preferably 12 to 80 parts by mass, more preferably 15 to 70 parts by mass, and even more preferably 20 to 60 parts by mass per 100 parts by mass of the rubber component (A).

[0127] In the case where the compression rubber layer has a double-layer structure, in the first compression rubber layer, the ratio of the filler (especially carbon black) is, for example, 10 to 100 parts by mass, preferably 20 to 80 parts by mass, more preferably 30 to 70 parts by mass, and more preferably 40 to 60 parts by mass relative to 100 parts by mass of the rubber component (first rubber component). In the second compression rubber layer, the ratio of the filler (especially carbon black) is, for example, 5 to 80 parts by mass, preferably 10 to 60 parts by mass, more preferably 15 to 50 parts by mass, and more preferably 20 to 40 parts by mass relative to 100 parts by mass of the rubber component (second rubber component). In the case where the compression rubber layer has a single layer, the ratio of the filler in the extension rubber layer may be the same as the ratio of the filler in the compression rubber layer. In the case where the compression rubber layer has a double-layer structure, the ratio of the filler in the extension rubber layer may be the same as the ratio of the filler in the first compression rubber layer.

[0128] In any of the compression rubber layer and the extension rubber layer, the proportion of carbon black relative to the total filler can be, for example, 50% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, or 100% by mass. When the proportion of carbon black relative to the total filler is too small, the rubber hardness of the compression rubber layer and the extension rubber layer may be reduced.

[0129] (D) Other additives

[0130] The crosslinked rubber composition may contain, as other additives (D), a crosslinking agent (or vulcanizing agent), a co-crosslinking agent (crosslinking aid), a crosslinking accelerator, a crosslinking retarder, a metal oxide (calcium oxide, barium oxide, iron oxide, copper oxide, titanium oxide, aluminum oxide, etc.), a softener (oils such as paraffin oil and naphthenic oil), a processing agent or a processing aid (for example, fatty acids such as stearic acid, fatty acid metal salts such as stearic acid metal salts, fatty acid amides such as stearic acid amide, wax, paraffin, etc.), an adhesion improver [for example, resorcinol-formaldehyde co-condensate (RF condensate), an amino resin (condensate of a nitrogen-containing cyclic compound and formaldehyde, for example, hexamethylolmelamine, hexaalkoxymethylmelamine (hexamethoxymethylmelamine, hexabutoxymethylmelamine) [melamine resins such as cyanamide, urea resins such as methylol urea, benzoguanamine resins such as methylol benzoguanamine resins, etc.), their co-condensates (resorcinol-melamine-formaldehyde co-condensates, etc.), anti-aging agents (antioxidants, heat aging agents, anti-bending cracking agents, anti-ozone degradation agents, etc.), plasticizers [aliphatic carboxylic acid plasticizers (adipate plasticizers, sebacate plasticizers, etc.), aromatic carboxylic acid ester plasticizers (phthalate plasticizers, trimellitic acid ester plasticizers, etc.), hydroxycarboxylic acid ester plasticizers, phosphate plasticizers, ether plasticizers, ether ester plasticizers, etc.], colorants, tackifiers, lubricants, coupling agents (silane coupling agents, etc.), stabilizers (ultraviolet absorbers, heat stabilizers, etc.), flame retardants, antistatic agents, etc. It should be noted that metal oxides can also function as crosslinking agents. In the adhesion improver, the resorcinol-formaldehyde co-condensate and the amino resin may be a primary condensate (prepolymer) of resorcinol and / or a nitrogen-containing cyclic compound (melamine, etc.) and formaldehyde.

[0131] As a crosslinking agent, conventional components can be used according to the type of rubber component (A), for example, metal oxides (magnesium oxide, zinc oxide, lead oxide, etc.), organic peroxides (diacyl peroxides, peroxyesters, dialkyl peroxides, etc.), sulfur-based crosslinking agents, etc. can be exemplified. As sulfur-based crosslinking agents, for example: powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, sulfur chloride (sulfur monochloride, sulfur dichloride, etc.) can be cited. These crosslinking agents can be used alone or in combination of two or more. In the case where the rubber component is chloroprene rubber, metal oxides (magnesium oxide, zinc oxide, etc.) can be used as crosslinking agents. It should be noted that metal oxides can also be used in combination with other crosslinking agents (sulfur-based crosslinking agents, etc.), and metal oxides and / or sulfur-based crosslinking agents can be used alone or in combination with crosslinking accelerators.

[0132] The proportion of the crosslinking agent can be selected from the range of, for example, about 1 to about 20 parts by mass relative to 100 parts by mass of the rubber component (A) in terms of solid content, depending on the types of the crosslinking agent and the rubber component (A). For example, the proportion of the metal oxide as a crosslinking agent is, for example, 1 to 20 parts by mass, preferably 3 to 17 parts by mass, more preferably 5 to 15 parts by mass, and more preferably 7 to 13 parts by mass relative to 100 parts by mass of the rubber component (A). In the case of combining a metal oxide as a crosslinking agent and a sulfur-based crosslinking agent, the proportion of the sulfur-based crosslinking agent is, for example, about 0.1 to about 50 parts by mass, preferably about 1 to about 30 parts by mass, and more preferably about 3 to about 10 parts by mass relative to 100 parts by mass of the metal oxide. The proportion of the organic peroxide is, for example, 1 to 8 parts by mass, preferably 1.5 to 5 parts by mass, and more preferably 2 to 4.5 parts by mass relative to 100 parts by mass of the rubber component (A).

[0133] Examples of the co-crosslinking agent (crosslinking aid or co-vulcanizing agent) include known crosslinking aids, such as polyfunctional (iso)cyanurates [e.g., triallyl isocyanurate (TAIC), triallyl cyanurate (TAC), etc.], polydienes (e.g., 1,2-polybutadiene), metal salts of unsaturated carboxylic acids [e.g., polyvalent metal salts of (meth)acrylate such as zinc (meth)acrylate and magnesium (meth)acrylate], oximes (e.g., quinone dioxime), guanidines (e.g., diphenylguanidine), polyfunctional (meth)acrylates [e.g., alkanediol di(meth)acrylates such as ethylene glycol di(meth)acrylate and butanediol di(meth)acrylate, alkane polyol di(meth)acrylates such as trimethylolpropane tri(meth)acrylate and pentaerythritol tetra(meth)acrylate], and polyfunctional (meth)acrylates.

[0063] , bismaleimides (aliphatic bismaleimides, such as N,N'-1,2-ethylenebismaleimide, N,N'-hexamethylenebismaleimide, 1,6'-bismaleimide-(2,2,4-trimethyl)cyclohexane and other alkylene bismaleimides; aromatic bismaleimides or aromatic bismaleimides, such as N,N'-m-phenylene dimaleimide, 4-methyl-1,3-phenylene dimaleimide, 4,4'-diphenylmethane dimaleimide, 2,2-bis[4-(4-maleimidophenoxy)phenyl]propane, 4,4'-diphenylether dimaleimide, 4,4'-diphenylsulfone dimaleimide, 1,3-bis(3-maleimidophenoxy)benzene, etc.), etc. These crosslinking aids can be used alone or in combination of two or more. Among these crosslinking aids, polyfunctional (iso)cyanurate, polyfunctional (meth)acrylate, bismaleimide (aromatic bismaleimide or aromatic bismaleimide such as N,N'-m-phenylene dimaleimide), are preferred, and bismaleimide is used in most cases. By adding a crosslinking aid (such as bismaleimide), the degree of crosslinking can be increased, and adhesion wear can be prevented.

[0134] The proportion of the co-crosslinking agent (crosslinking aid) such as bismaleimide is, in terms of solid content, for example, 0.1 to 10 parts by mass, preferably 0.5 to 8 parts by mass, more preferably 1 to 5 parts by mass, and even more preferably 2 to 4 parts by mass per 100 parts by mass of the rubber component (A).

[0135] In the case where the compression rubber layer has a double-layer structure, in the first compression rubber layer, the ratio of the co-crosslinking agent is, for example, 0.5 to 10 parts by mass, preferably 1 to 8 parts by mass, more preferably 1.5 to 5 parts by mass, and more preferably 2 to 4 parts by mass, relative to 100 parts by mass of the rubber component (first rubber component). In the second compression rubber layer, the ratio of the co-crosslinking agent is, for example, 10 parts by mass or less, preferably 5 parts by mass or less, and more preferably 1 part by mass or less, relative to 100 parts by mass of the rubber component (second rubber component). In the case where the compression rubber layer has a single-layer structure, the ratio of the co-crosslinking agent in the extension rubber layer may be the same as the ratio of the co-crosslinking agent in the compression rubber layer. In the case where the compression rubber layer has a double-layer structure, the ratio of the co-crosslinking agent in the extension rubber layer may be the same as the ratio of the co-crosslinking agent in the first compression rubber layer.

[0136] Examples of the crosslinking accelerator (vulcanization accelerator) include thiuram accelerators [e.g., tetramethylthiuram monosulfide (TMTM), tetramethylthiuram disulfide (TMTD), tetraethylthiuram disulfide (TETD), tetrabutylthiuram disulfide (TBTD), dipentamethylenethiuram tetrasulfide (DPTT), N,N'-dimethyl-N,N'-diphenylthiuram disulfide, etc.], thiazole accelerators [e.g., 2-mercaptobenzothiazole , zinc salt of 2-mercaptobenzothiazole, 2-mercaptobenzothiazoline, dibenzothiazole disulfide, 2-(4'-morpholinyl dithio)benzothiazole, etc.], sulfonamide accelerators [for example, N-cyclohexyl-2-benzothiazole sulfonamide (CBS), N,N'-dicyclohexyl-2-benzothiazole sulfonamide, etc.], guanidines (diphenylguanidine, di-o-tolylguanidine, etc.), ureas or thioureas accelerators (for example, ethylenethiourea, etc.), dithiocarbamates, xanthates, etc. These crosslinking accelerators can be used alone or in combination of two or more. Among these crosslinking accelerators, TMTD, DPTT, CBS, etc. are commonly used.

[0137] The proportion of the crosslinking accelerator may be 15 parts by mass or less (e.g., 0 to 15 parts by mass), for example, 0.1 to 10 parts by mass, preferably 0.2 to 5 parts by mass, more preferably 0.3 to 3 parts by mass, and more preferably 0.5 to 1.5 parts by mass, relative to 100 parts by mass of the rubber component (A) in terms of solid content. In the case where the compression rubber layer is a single-layer structure, the proportion of the crosslinking accelerator in the extension rubber layer may be the same as the proportion of the crosslinking accelerator in the compression rubber layer. In the case where the compression rubber layer is a double-layer structure, the proportion of the crosslinking accelerator in the extension rubber layer may be the same as the proportion of the crosslinking accelerator in the first compression rubber layer.

[0138] The proportion of the softener (oils such as cycloparaffin oil) can be 30 parts by mass or less (e.g., 0 to 30 parts by mass), for example, 1 to 30 parts by mass, preferably 3 to 20 parts by mass, and more preferably 3 to 10 parts by mass, based on solid content per 100 parts by mass of the rubber component (A).

[0139] In the case where the compression rubber layer has a double-layer structure, in the first compression rubber layer, the ratio of the softener is, for example, 1 to 30 parts by mass, preferably 3 to 20 parts by mass, and more preferably 3 to 10 parts by mass relative to 100 parts by mass of the rubber component (first rubber component). In the second compression rubber layer, the ratio of the softener is, for example, 20 parts by mass or less, preferably 10 parts by mass or less, and more preferably 5 parts by mass or less relative to 100 parts by mass of the rubber component (second rubber component). In the case where the compression rubber layer has a single-layer structure, the ratio of the softener in the extension rubber layer may be the same as the ratio of the softener in the compression rubber layer. In the case where the compression rubber layer has a double-layer structure, the ratio of the softener in the extension rubber layer may be the same as the ratio of the softener in the first compression rubber layer.

[0140] The proportion of the processing agent or processing aid (stearic acid, etc.) can be 10 parts by mass or less (e.g., 0 to 10 parts by mass), for example, 0.1 to 5 parts by mass, preferably 0.5 to 3 parts by mass, and more preferably 1 to 3 parts by mass, based on 100 parts by mass of the rubber component (A) in terms of solid content.

[0141] The ratio of the antioxidant is, for example, 0.5 to 15 parts by mass, preferably 1 to 10 parts by mass, more preferably 2.5 to 7.5 parts by mass, and further preferably 3 to 7 parts by mass, based on 100 parts by mass of the rubber component (A) in terms of solid content.

[0142] The proportion of the plasticizer may be 30 parts by mass or less (e.g., 0 to 30 parts by mass), for example, 0.5 to 20 parts by mass, preferably 1 to 10 parts by mass, and more preferably 3 to 7 parts by mass, based on 100 parts by mass of the rubber component (A) in terms of solid content.

[0143] In the case where the compression rubber layer has a double-layer structure, in the first compression rubber layer, the ratio of the plasticizer is, for example, 20 parts by mass or less, preferably 10 parts by mass or less, and more preferably 5 parts by mass or less, relative to 100 parts by mass of the rubber component (first rubber component). In the second compression rubber layer, the ratio of the plasticizer is, for example, 1 to 30 parts by mass, preferably 3 to 20 parts by mass, and more preferably 3 to 10 parts by mass relative to 100 parts by mass of the rubber component (second rubber component). In the case where the compression rubber layer has a single-layer structure, the ratio of the plasticizer in the extension rubber layer may be the same as the ratio of the plasticizer in the compression rubber layer. In the case where the compression rubber layer has a double-layer structure, the ratio of the plasticizer in the extension rubber layer may be the same as the ratio of the plasticizer in the first compression rubber layer.

[0144] [Core layer]

[0145] The core layer may contain a core. As described above, the core layer may be formed only of a core. From the perspective of being able to suppress interlayer peeling and improve belt durability, for example Figures 1 to 4 As shown, it is preferred that the core layer (adhesive rubber layer) is formed of a cross-linked rubber composition in which a core is embedded. The core layer formed of a cross-linked rubber composition in which a core is embedded is generally referred to as an adhesive rubber layer, and the core may be embedded in the layer formed of the cross-linked rubber composition containing a rubber component. The adhesive rubber layer is preferably interposed between the compression rubber layer and the extension rubber layer to bond the compression rubber layer to the extension rubber layer, and the core is embedded in the adhesive rubber layer.

[0146] The average thickness of the core layer (particularly the adhesive rubber layer) is, for example, 0.2 to 5 mm, preferably 0.3 to 4 mm, more preferably 0.5 to 3.5 mm, more preferably 0.8 to 3 mm, and most preferably 1 to 2.5 mm.

[0147] (Crosslinked rubber composition of core layer)

[0148] The rubber hardness Hs of the cross-linked rubber composition forming the core layer (especially the adhesive rubber layer) is, for example, 72 to 80°, preferably 73 to 78°, and more preferably 75 to 77°. If the rubber hardness is too small, the lateral pressure resistance may be reduced. On the contrary, if the rubber hardness is too large, the cross-linked rubber composition around the core may become rigid and the core may be difficult to bend, resulting in thermal degradation (cracking) of the core layer, bending fatigue of the core, etc., and the core may peel off.

[0149] As the rubber component (A1) constituting the cross-linked rubber composition forming the core layer, the rubber components exemplified as the rubber components (A) for the compression rubber layer and the extension rubber layer can be used, and a preferred embodiment can be selected from the preferred embodiments of the rubber component (A) described above.

[0150] In addition to the rubber component (A1), the cross-linked rubber composition of the core layer may further include a filler (A2). As the filler (A2), the fillers exemplified as the fillers (C) for the compression rubber layer and the extension rubber layer may be used. Among the above fillers, carbon black and reinforcing silica are preferred, and a combination of carbon black and reinforcing silica is particularly preferred.

[0151] In the core layer, the proportion of the filler (A2) is, for example, 1 to 100 parts by mass, preferably 10 to 80 parts by mass, more preferably 30 to 70 parts by mass, and more preferably 40 to 60 parts by mass relative to 100 parts by mass of the rubber component (A1). In the case of combining carbon black and reinforcing silica, the proportion of the reinforcing silica is, for example, 10 to 200 parts by mass, preferably 30 to 100 parts by mass, and more preferably 50 to 80 parts by mass relative to 100 parts by mass of the carbon black.

[0152] In addition to the above-mentioned rubber component (A1), the cross-linked rubber composition of the core layer may further include other additives (A3). As other additives (A3), the additives exemplified as other additives (D) for the compression rubber layer and the extension rubber layer may be used, and preferably a cross-linking agent, a cross-linking accelerator, a processing agent or a processing aid, a plasticizer, an anti-aging agent, etc. may be used. The proportion of other additives (A3) also includes a preferred range and can be selected from the same range as the proportion of the additives (D) for the compression rubber layer and the extension rubber layer.

[0153] The rubber hardness Hs of the core layer can be selected from a range of, for example, about 60° to about 90°, preferably 72° to 80°, more preferably 73° to 78°, further preferably 74° to 78°, and most preferably 75° to 77°. The tensile strength of the core layer in the belt width direction is, for example, 12 to 20 MPa, preferably 13 to 18 MPa, and further preferably 14 to 17 MPa.

[0154] (A4) Core

[0155] The core (A4) contained in the core layer is not particularly limited, and is usually a core wire (twisted rope) arranged at a prescribed interval in the belt width direction. The core wires are extended and arranged along the length direction of the belt, and can be extended and arranged in parallel at a prescribed interval in parallel with the length direction of the belt. From the perspective of productivity, they are usually extended and arranged in a spiral shape in parallel at a prescribed interval approximately parallel to the length direction of the belt. When the core wires are arranged in a spiral shape, the angle of the core wire relative to the length direction of the belt can be, for example, less than 5°. From the perspective of belt mobility, the closer to 0°, the more preferred. In addition, the distance between the centers of adjacent cores, that is, the pitch or interval (especially the rotation pitch of the core wire) is preferably set to a range of 1.0 to 3.6 mm, more preferably set to a range of 1.2 to 3 mm, and more preferably set to a range of 1.4 to 2.4 mm.

[0156] When the core (A4) is embedded in the adhesive rubber constituting the core layer, a part of it may be embedded in the adhesive rubber, but from the aspect of being able to improve durability, it is preferably a form in which the core is not exposed on the surface of the core layer (a form in which the entire core is completely embedded in the adhesive rubber). As the core (A4), a cord is preferred.

[0157] As the fibers constituting the core wire, for example, the fibers exemplified as the fibers constituting the above-mentioned short fibers (B) constituting the above-mentioned compression rubber layer and the extension rubber layer can be cited. The above-mentioned fibers can be used alone or in combination of two or more. Among the above-mentioned fibers, C esters such as ethylene terephthalate and ethylene 2,6-naphthalate are generally used from the aspect of high modulus. 2-4 Alkylene-C 8-14 Synthetic fibers such as polyester fibers (polyalkylene aromatic ester fibers) and polyamide fibers (aramid fibers, etc.), inorganic fibers such as carbon fibers, etc., with aromatic esters as the main structural units, preferably polyester fibers (especially polyethylene terephthalate fibers, polyethylene naphthalate fibers) and polyamide fibers (especially aramid fibers).

[0158] The fibers constituting the core yarn may be in the form of a multifilament yarn. The fineness of the multifilament yarn may be, for example, 2000 to 10000 deniers (particularly 4000 to 8000 deniers). The multifilament yarn may contain, for example, about 100 to about 5000 filaments, preferably 500 to 4000 filaments, and more preferably 1000 to 3000 filaments.

[0159] As the core wire, a twisted rope (e.g., ply twist, unidirectional twist, straight twist, etc.) using multifilament yarn can be generally used. The average wire diameter of the core wire (fiber diameter of the twisted rope) can be, for example, 0.5 to 3 mm, preferably 0.6 to 2.5 mm, more preferably 0.7 to 2 mm, and more preferably 1.1 to 2 mm.

[0160] When the core wire is embedded in the adhesive rubber, it may be surface treated in order to improve the adhesion to the cross-linked rubber composition forming the adhesive rubber. As the surface treatment agent, the surface treatment agent exemplified as the surface treatment agent for the short fiber (B) of the compression rubber layer and the extension rubber layer may be cited. The surface treatment agent may be used alone or in combination of two or more, and the treatment may be performed multiple times in sequence with the same or different surface treatment agents. The core wire is preferably subjected to bonding treatment with at least RFL liquid.

[0161] [Outer cloth]

[0162] The outer covering cloth (covering cloth) is formed of a conventional cloth. Examples of the cloth include woven cloth, knitted cloth (weft knitted cloth, warp knitted cloth), nonwoven cloth, etc. Among them, woven cloth such as plain weave, twill weave, satin weave, woven cloth with a crossing angle of more than 90° and less than about 120°, knitted cloth, etc. are preferred, and woven cloth commonly used as a covering cloth for transmission belts for general industrial or agricultural machinery [plain weave with a crossing angle of right angles, plain weave with a crossing angle of more than 90° and less than about 120° (wide-angle canvas)] is particularly preferred. Furthermore, in applications requiring durability, the cloth may be a wide-angle canvas.

[0163] As the fibers constituting the fabric, for example, the fibers exemplified as the fibers constituting the short fibers (B) of the compression rubber layer and the extension rubber layer can be cited. These fibers may be single yarns using only one type of fiber, or composite yarns (blended yarns, etc.) combining two or more types of fibers.

[0164] Among these fibers, blended yarns of polyester fibers and cellulose fibers are preferred because of their excellent mechanical properties and economic efficiency.

[0165] The polyester fiber may be a polyalkylene arylate fiber. Examples of the polyalkylene arylate fiber include polyethylene terephthalate (PET) fiber, polyethylene naphthalate (PEN) fiber, and the like. 2-4 Alkylene-C 8-14 Aryl ester fibers, etc. These polyester fibers may be used alone or in combination of two or more.

[0166] Cellulose fibers include cellulose fibers (cellulose fibers from plants, animals, bacteria, etc.) and fibers of cellulose derivatives. Examples of cellulose fibers include: wood pulp (coniferous tree pulp, broadleaf tree pulp, etc.), bamboo fiber, sugarcane fiber, seed hair fiber (cotton fiber (cotton linter), kapok, etc.), bast fiber (hemp, paper mulberry, yellow daphne, etc.), leaf fiber (Manila hemp, New Zealand hemp, etc.) and other cellulose fibers (pulp fibers) from natural plants; cellulose fibers from animals such as ascidian cellulose; bacterial cellulose fibers; cellulose from algae, etc. Fibers of cellulose derivatives include, for example: cellulose ester fibers; regenerated cellulose fibers (rayon, cuprammonium fibers, lyocell fibers, etc.). These cellulose fibers may also be used alone or in combination of two or more. Among them, cotton fibers are preferred.

[0167] The mass ratio of the polyester fibers to the cellulose fibers is, for example, the former / the latter=90 / 10 to 10 / 90, preferably 80 / 20 to 20 / 80, and more preferably 70 / 30 to 30 / 70 (particularly 60 / 40 to 40 / 60).

[0168] The average fineness of the yarn constituting the cloth is, for example, 5 to 30 deniers, preferably 10 to 25 deniers, and more preferably 15 to 23 deniers.

[0169] The weight per unit area of ​​the fabric (raw fabric) is, for example, 100 to 500 g / m 2 , preferably 200 to 400 g / m 2 , more preferably 250 to 350 g / m 2 .

[0170] The average thickness of the fabric (raw fabric) is, for example, 0.1 to 1.5 mm, preferably 0.2 to 1 mm, and more preferably 0.3 to 0.7 mm.

[0171] When the fabric (raw fabric) is a woven fabric, the yarn density (density of warp and weft) of the fabric is, for example, 60 to 100 yarns / 50 mm, preferably 70 to 90 yarns / 50 mm, and more preferably 72 to 80 yarns / 50 mm.

[0172] The outer covering cloth may be single-layered or multi-layered (for example, about two to five layers, preferably about two to four layers), and is preferably single-layered (one layer) or double-layered (two layers) in terms of productivity and the like.

[0173] In order to improve the adhesion with the belt body, the outer cover cloth may be a cloth with a rubber component attached. The outer cover cloth with a rubber component attached may be a cloth subjected to an adhesive treatment such as soaking (impregnation) in a rubber paste obtained by dissolving a rubber composition in a solvent, or rubbing (rubbing) a solid rubber composition. The adhesive treatment may be applied to at least one surface of the cloth, and preferably at least the surface in contact with the belt body is treated.

[0174] As the rubber component constituting the rubber composition attached to the outer cover cloth, the rubber component exemplified as the rubber component (A) for the compression rubber layer and the extension rubber layer can be utilized, and a preferred embodiment can also be selected from the same embodiments as the rubber component (A) for the compression rubber layer and the extension rubber layer.

[0175] In addition to the above-mentioned rubber components, the rubber composition attached to the outer cover cloth may further contain a filler. As the filler, the filler exemplified as the filler (C) for the compression rubber layer and the extension rubber layer may be used, and the preferred form and the proportion of carbon black in the filler may also be selected in the same manner as the proportion of the filler (C) for the compression rubber layer and the extension rubber layer.

[0176] In the rubber composition attached to the outer cloth, the proportion of filler (especially carbon black) relative to 100 parts by mass of the rubber component is, for example, about 5 parts by mass to about 80 parts by mass, preferably about 10 parts by mass to about 75 parts by mass, and further preferably about 30 parts by mass to about 70 parts by mass (especially about 40 parts by mass to about 60 parts by mass).

[0177] In addition to the above-mentioned rubber components, the rubber composition attached to the outer cover cloth may also contain a plasticizer. As the plasticizer, the plasticizers exemplified as the plasticizers for the compression rubber layer and the extension rubber layer may be used, and a preferred mode may also be selected from the same mode as the plasticizers for the compression rubber layer and the extension rubber layer.

[0178] In the rubber composition attached to the outer cover cloth, the proportion of the plasticizer is, for example, 3 to 50 parts by mass, preferably 5 to 40 parts by mass, more preferably 10 to 30 parts by mass (particularly 15 to 25 parts by mass) based on 100 parts by mass of the rubber component.

[0179] In addition to the above-mentioned rubber components, the rubber composition attached to the outer cloth may also contain short fibers and other additives. As short fibers, the short fibers (B) exemplified in the items of the compression rubber layer and the extension rubber layer may be used. As other additives, the additives exemplified as other additives (D) for the compression rubber layer and the extension rubber layer may be used. Among them, in the rubber composition attached to the outer cloth, in addition to the above-mentioned rubber components, it is preferred that a crosslinking agent or vulcanizing agent, a crosslinking accelerator, a processing agent or a processing aid, and an anti-aging agent are also included. The proportion of these additives relative to the rubber component can be selected in the same manner as for the compression rubber layer and the extension rubber layer.

[0180] The rubber hardness Hs of the cross-linked rubber composition attached to the outer cover is, for example, 40 to 70°, preferably 45 to 65°, and more preferably 50 to 60°. The tensile strength of the cross-linked rubber composition attached to the outer cover in the belt width direction is, for example, 5 to 20 MPa, preferably 10 to 15 MPa, and more preferably 12 to 13 MPa.

[0181] The average thickness of the outer cloth (the average thickness of each layer in the case of multiple layers) is, for example, 0.4 to 2 mm, preferably 0.5 to 1.4 mm. If the thickness of the outer cloth is too thin, the wear resistance may be reduced. On the contrary, if the thickness of the outer cloth is too thick, the bendability of the belt may be reduced.

[0182] [Reinforced fabric layer]

[0183] Each of the cover V-belt portions may further include a reinforcing cloth layer between the inner peripheral surface (the surface on the inner peripheral side) of the compression rubber layer and the cover. Figure 7 An example of a V-belt portion having a reinforcing fabric layer is shown in FIG. Figure 6 The V-belt portion of the cover cloth similarly comprises an extension rubber layer 53, a core layer (adhesive rubber layer) 54 in which a core (core wire) 54a is embedded, a first compression rubber layer 55a, a second compression rubber layer 55b, and an outer cover cloth 56. Figure 6 Unlike the wrapped V-belt portion, a reinforcing cloth layer 57 is interposed between the second compression rubber layer 55 b and the outer cloth 56 .

[0184] The reinforcing cloth layer is also formed of a conventional cloth like the outer cloth. The cloth can be selected from the cloths exemplified in the item of the outer cloth, and a preferred embodiment can also be selected from the preferred embodiments of the outer cloth.

[0185] In order to improve the adhesion with the compression rubber layer and the outer cover, the reinforcing cloth layer may be a cloth with a rubber component attached. The cloth with a rubber component attached may be, for example, a cloth subjected to an adhesive treatment such as soaking (impregnation) a rubber paste obtained by dissolving a rubber composition in a solvent, or rubbing (rubbing) a solid rubber composition. As the rubber composition, the rubber composition exemplified as the rubber composition attached to the outer cover may be used, and the preferred method is the same as that of the outer cover. The adhesive treatment may be performed on at least one surface of the cloth, preferably at least on the surface in contact with the compression rubber layer, and particularly preferably on both sides.

[0186] The average thickness of the reinforcing fabric layer is, for example, 0.4 to 2 mm, preferably 0.5 to 1.4 mm. If the thickness of the reinforcing fabric layer is too thin, the effect of improving the wear resistance may be reduced. On the contrary, if the thickness of the reinforcing fabric layer is too thick, the bendability of the belt may be reduced.

[0187] <Bundle (Joining member)>

[0188] The strapping belt for connecting the outer peripheral surfaces of two or more cloth-wrapped V-belt parts has a short fiber-containing rubber layer (cross-linked rubber composition) in which the short fibers are arranged (oriented) in the belt width direction. Two or more ribs extending in the belt length direction are formed at intervals in the belt width direction on the belt outer peripheral side of the short fiber-containing rubber layer. The strapping belt having the short fiber-containing rubber layer may further have a fabric layer on the belt inner peripheral side of the short fiber-containing rubber layer as needed.

[0189] [Shape of the ribs]

[0190] The cross-sectional shape of each rib formed in parallel in the belt width direction is not particularly limited as long as it has a V-shaped groove that can be fitted into a V-belt pulley (V-rib pulley). Figure 3 As shown in (Implementation 3), all ribs have the same cross-sectional shape, or Figure 1 As shown in (Implementation 1), the cross-sectional shape of the ribs at the two ends is different from the cross-sectional shape of the other ribs. The above-mentioned ribs may be ribs (trapezoidal ribs) whose cross-sectional shape in the belt width direction is an inverted V-shape (trapezoidal). In addition to the trapezoidal ribs, they may also be approximately trapezoidal ribs. The approximately trapezoidal ribs may be ribs located at the two ends of the ribs arranged in the belt width direction. As the shape of the approximately trapezoidal ribs, it may be a quadrilateral ( Figure 1In the ribs arranged along the belt width direction, the cross-sectional shape of the ribs located at both ends is a quadrilateral or a right-angled trapezoid). As the shape of the ribs that are approximately trapezoidal, at least one hypotenuse of the trapezoid may be a pentagon or a hexagon that is perpendicular to the lower base from the upper base of the trapezoid toward the lower base. That is, the combined V-belt is cut and manufactured according to the width of the wrapped V-belt portion. Therefore, the shape of two or more ribs may be a shape that is cut between adjacent ribs, or a shape in which the ribs are cut (the cross-section is the above-mentioned right-angled trapezoid or the above-mentioned pentagon). The V-rib angle of the hypotenuse of the trapezoid as the cross-sectional shape of the rib ( Figure 5 The angle α2 in the V-rib (the angle of the side of the inverted V-shaped shape) is, for example, 20 to 100°, preferably 25 to 60°, further preferably 30 to 50°, more preferably 35 to 45°, and most preferably 38 to 42° (particularly 40°) relative to the belt thickness direction. The V-rib angle (α2) can be adjusted to Figure 5 The ratio of P1 to P2 (P1 / P2) and Figure 5 The ratio of H2 to H1 (H2 / H1) shown is within the above range.

[0191] The connecting portion between the wrapped V-belt portions (a region of the strapping belt that does not contact the outer peripheral surface of the wrapped V-belt portion and connects the adjacent wrapped V-belt portions in the belt width direction) can be as follows: Figure 3 As shown in the figure, it is formed by the rib peak (the maximum thickness part of the strapping tape), or it can be formed by the rib peak (the maximum thickness part of the strapping tape) as shown in the figure. Figure 1 As shown in FIG. 1 , the rib valley portion (the smallest thickness portion of the strapping tape) is formed. Figure 3 As shown in the figure, the top center of the rib is located in the gap (connecting portion) between adjacent V-belt portions of the wrapping cloth, or as shown in the figure, Figure 1 As shown in FIG. 1 , the bottom of the V-shaped groove is located in the gap (connecting portion) between adjacent V-belt portions of the wrapping cloth. Figure 3 As shown the connection is formed by the rib peaks.

[0192] [Rubber layer containing short fibers]

[0193] The short fiber-containing rubber layer contains short fibers arranged (oriented) in the belt width direction. Specifically, the short fibers of the short fiber-containing rubber layer may be arranged substantially in parallel in the belt width direction.

[0194] It should be noted that, in the present application, the arrangement of short fibers along the width direction of the belt means that the angle formed by the direction of the short fiber arrangement and the width direction of the belt as observed from the length direction of the belt is generally approximately less than about 20° (for example, about 0° to about 10°), preferably less than 10° (for example, 0 to 5°, especially about 0°).

[0195] In addition, in the present application, as long as the wear resistance of the friction transmission surface (friction transmission surface of the rib) in the rubber layer containing short fibers, the rigidity in the belt width direction (resistance to lateral pressure), and the bending property in the belt length direction (softness, winding property on the pulley) can be balanced, the rubber layer containing short fibers may also contain short fibers that are not arranged in the belt width direction. That is, the short fibers contained in the rubber layer containing short fibers do not have to be oriented in a straight line in the belt width direction. For example, when viewed from the belt length direction, the angle between the direction of arrangement of the short fibers and the belt width direction may be locally (for example, in the layer in the center of the belt thickness direction) an angle exceeding 20° (for example, about 30°). When viewed from the belt and thickness direction, the angle may be an angle exceeding 20° (for example, about 30°) as a whole or locally. In short, in the tensile property test of the cross-linked rubber sheet [JIS K6251 (2017)], the cross-linked rubber composition as the short fiber-containing rubber layer may be formed so that the elongation at break (%) in the direction perpendicular to the short fiber texture is significantly greater (e.g., about 10 times) than the elongation at break (%) in the direction of the short fiber texture. Specifically, among the short fibers contained in the short fiber-containing rubber layer, the proportion of the short fibers arranged in the belt width direction may be, for example, 80% or more, preferably 90% or more, and more preferably 95% or more.

[0196] In that the ribs (the two inclined surfaces on both sides of the ribs) form the friction transmission surface during back drive, the rubber layer containing short fibers is functionally equivalent to the compression rubber layer. However, in the preferred embodiment of the combined V-belt, the arrangement pitch (P2) of the ribs is smaller than the arrangement pitch (P1) of the V-belt along the belt width direction. Inevitably, the volume (cross-sectional area) of the ribs is smaller than the volume (cross-sectional area) of the V-belt. Therefore, it can be said that the ribs can disperse the axial load (lateral pressure) compared to the V-belt, and it is easy to ensure the rigidity against buckling deformation. Therefore, like the compression rubber layer constituting each V-belt, the rubber layer containing short fibers can be a single layer (one layer) or a rubber layer having a laminated structure including two rubber layers with different rubber hardnesses and with the rubber hardness of each layer adjusted. Considering the above-mentioned functions, characteristic surfaces, productivity, etc., the rubber layer containing short fibers is preferably set to a single layer (one layer).

[0197] In addition, as described above, the ribs can disperse the axial load (lateral pressure) compared to the V-belt portion, and can easily ensure rigidity against buckling deformation. Therefore, the rubber hardness of the rubber layer containing short fibers can be an intermediate level of the rubber hardness of each layer of the two-layer compression rubber layer (first compression rubber layer, second compression rubber layer).

[0198] The rubber hardness Hs of the rubber layer containing short fibers can be selected from a range of about 70° to about 95°, for example, preferably 78° to 91°, more preferably 80° to 90°, further preferably 82° to 89°, and most preferably 83° to 88°. If the rubber hardness is too low, the lateral pressure resistance and abrasion resistance may be reduced. On the contrary, if the rubber hardness is too high, the bending property may be reduced.

[0199] The tensile strength of the rubber layer containing short fibers in the belt width direction is, for example, 12 to 35 MPa, preferably 13 to 30 MPa, more preferably 14 to 26 MPa, and more preferably 15 to 20 MPa. If the tensile strength is too low, the lateral pressure resistance may be reduced. On the contrary, if the tensile strength is too high, the bending property may be reduced.

[0200] The average thickness of the short fiber-containing rubber layer is different between the case where the strapping tape is formed of only the short fiber-containing rubber layer and the case where the strapping tape is formed of a fabric layer further including a fiber structure.

[0201] like Figure 1 As shown, when the strapping tape is formed only of a rubber layer containing short fibers (embodiment 1), the average thickness of the rubber layer containing short fibers is equal to the thickness (H3) of the strapping tape (T), for example, 4.5 to 6.5 mm, preferably 4.6 to 6 mm. In this case, if both rigidity in the width direction of the tape and suppression of loop breakage (especially suppression of loop breakage at the connecting portion) are taken into consideration, the thickness (d) of the base portion (the minimum thickness portion) needs to be ensured to be at least about 2 mm (for example, 1.8 to 2.3 mm).

[0202] like Figure 2 As shown, when the binding belt is formed of a fabric layer including a short fiber-containing rubber layer and a fiber structure laminated on the inner peripheral side of the belt (Embodiment 2), the average thickness of the short fiber-containing rubber layer is, for example, 3 to 5.3 mm, preferably 3 to 5 mm.

[0203] However, for the strapping tape formed only of the rubber layer containing short fibers (embodiment 1), in order to prevent the thickness of the rubber layer containing short fibers (particularly the thickness d of the base portion) from being increased more than necessary (to be formed thinly to the same level as the thickness of the rubber layer containing short fibers in embodiment 2), while achieving both rigidity in the width direction of the tape and suppression of loop breakage at the connecting portion, it is preferred as follows Figure 3 As shown in (Embodiment 3), the connecting portion is formed at the maximum thickness portion (rib crest portion) of the binding band.

[0204] The rubber layer containing short fibers can adjust the rubber hardness and the like by appropriately adjusting the composition of the composition. The method for adjusting the rubber hardness and the like is not particularly limited, and the rubber hardness can be adjusted by changing the composition and / or type of the components constituting the composition. From the perspective of simplicity and the like, it is preferred to adjust the rubber hardness by changing the ratio and / or type of short fibers and fillers.

[0205] As the rubber component (B1) constituting the cross-linked rubber composition forming the short fiber-containing rubber layer, the rubber components exemplified as the rubber components (A) for the compression rubber layer and the extension rubber layer can be utilized, and a preferred embodiment can also be selected from the preferred embodiments of the rubber component (A) described above.

[0206] In addition to the above-mentioned rubber component (B1), the cross-linked rubber composition of the rubber layer containing short fibers also contains short fibers (B2). As short fibers (B2), short fibers exemplified as short fibers (B) of the compression rubber layer and the extension rubber layer can be cited. Among the above-mentioned short fibers, aromatic polyamide fibers and / or polyester fibers are preferred, and a combination of aromatic polyamide fibers and polyester fibers is particularly preferred. Regarding the average fiber diameter and average length of the short fibers (B2), including the preferred mode, they can be selected from the average fiber diameter and average length of the short fibers (B). The proportion of the short fibers (B2) is, for example, 1 to 50 parts by mass, preferably 5 to 30 parts by mass, and more preferably 10 to 30 parts by mass relative to 100 parts by mass of the rubber component (B1). The short fibers (B2) can be bonded (or surface treated) by conventional methods. As a method for bonding treatment, it can be selected from the methods described in the items of the short fibers (B) of the compression rubber layer and the extension rubber layer.

[0207] In addition to the above-mentioned rubber component (B1), the cross-linked rubber composition of the rubber layer containing short fibers may also contain a filler (B3). As filler (B3), fillers exemplified as fillers (C) for compression rubber layers and extension rubber layers, etc. may be cited. Among the above-mentioned fillers, carbon black is preferred. The proportion of filler (B3) is, for example, 5 to 80 parts by mass, preferably 10 to 60 parts by mass, more preferably 15 to 50 parts by mass, and more preferably 20 to 40 parts by mass relative to 100 parts by mass of the rubber component (B1).

[0208] In addition to the above-mentioned rubber component (B1), the cross-linked rubber composition of the rubber layer containing short fibers may further contain other additives (B4). As other additives (B4), the additives exemplified as other additives (D) for the compression rubber layer and the extension rubber layer may be used, and preferably a cross-linking agent, a cross-linking accelerator, a processing agent or a processing aid, a plasticizer, an anti-aging agent, etc. may be used. The proportions of other additives (B4) relative to 100 parts by mass of the rubber component (B1) may be selected from the same range as the proportions of the additives (D) for the compression rubber layer and the extension rubber layer, including the preferred range.

[0209] [Fabric layer]

[0210] From the perspective of preventing loop breakage, the strapping tape can be Figure 2 As shown in (Embodiment 2), the inner side of the belt further includes a fabric layer including a fiber structure. As the fiber structure constituting the fabric layer, conventional fabrics can be used, and examples thereof include: cord fabric, woven fabric, mesh fabric, net (net structure or mesh), etc. Among them, from the perspective of being able to take into account both the suppression of loop breakage and the bending property (flexibility) in the longitudinal direction of the belt, and also having an excellent balance with productivity, a woven fabric or woven fabric having a woven structure such as cord weave or plain weave is preferred, and cord fabric is particularly preferred.

[0211] In the cord fabric, from the aspect of being able to further improve the resistance to the tensile force acting in the belt width direction, it is preferred to use a cord fabric containing two or more filaments extending in the belt width direction. It is particularly preferred to use a cord fabric containing two or more first filaments (thread bodies) extending in the belt width direction and two or more second filaments having a lower thread density (arrangement density) than the two or more first filaments and extending in a direction intersecting the belt width direction.

[0212] It should be noted that, in the present application, the filaments extending in the belt width direction refer to filaments extending substantially parallel to the belt width direction. Furthermore, "substantially parallel" means that the angle between the direction in which the filaments extend and the belt width direction is, for example, about 10° or less (for example, about 0° to about 5°), preferably 3° or less (for example, 0 to 1°, especially about 0°).

[0213] The yarn density of the first filament (the number of yarns per 5 cm in the tape length direction) is, for example, 10 to 300 yarns / 5 cm, preferably 50 to 200 yarns / 5 cm, further preferably 80 to 180 yarns / 5 cm, more preferably 100 to 170 yarns / 5 cm, and most preferably 120 to 150 yarns / 5 cm.

[0214] The fiber density of the second filaments is, for example, 1 to 30 strands / 5 cm, preferably 2 to 10 strands / 5 cm, further preferably 2 to 8 strands / 5 cm, further preferably 3 to 7 strands / 5 cm, and most preferably 4 to 6 strands / 5 cm.

[0215] As the fibers constituting the first filament and the second filament, for example, the fibers exemplified as the fibers constituting the above-mentioned short fibers (B) constituting the compression rubber layer and the extension rubber layer can be cited. Among the above-mentioned short fibers, as the first filament, polyester fibers and polyamide fibers are preferred, and aliphatic polyamide fibers such as polyamide 66 fibers are particularly preferred. As the second filament, cellulose fibers are preferred, and cellulose fibers such as cotton fibers are particularly preferred.

[0216] When the first filament is a polyester fiber or a polyamide fiber, the fineness of the first filament (the total fineness in the case of a multifilament yarn, etc.) is, for example, 100 to 1000 dtex, preferably 200 to 800 dtex, and more preferably 300 to 500 dtex.

[0217] When the second filament is cellulose fiber such as cotton fiber, the thickness (number of counts) of the second filament is, for example, about 5 to 100 counts, preferably about 7 to 50 counts, and more preferably about 10 to 30 counts.

[0218] In order to improve the adhesion with the rubber component (crosslinked rubber composition) etc., the fiber structure can be subjected to conventional bonding treatment or surface treatment (e.g., treatment with a treatment liquid containing bonding components). As the bonding treatment method, it can be selected from the methods described in the short fibers (B) of the compression rubber layer and the extension rubber layer.

[0219] The average thickness of the fiber structure is, for example, about 0.1 mm to about 0.5 mm, preferably about 0.2 mm to about 0.3 mm. If the fiber structure is too thin, interlayer delamination and ring breakage may occur. If the fiber structure is too thick, the bendability of the belt may be reduced.

[0220] From the perspective of suppressing interlayer peeling (between the wrapped V-belt portion and / or the rubber layer containing short fibers and the fiber structure) and suppressing loop breakage (including suppressing the propagation of defects) in addition to suppressing peeling of the fiber structure, the fabric layer is preferably a method in which the fiber structure is buried (sandwiched) in the rubber component (the fabric layer sandwiches the rubber). This method is a method in which the fiber structure is buried in the cross-linked rubber composition.

[0221] As the rubber component (C1) of the crosslinked rubber composition constituting the fabric layer, the rubber components exemplified as the rubber component (A) for the compression rubber layer and the extension rubber layer can be used, and a preferred embodiment can be selected from the preferred embodiments of the rubber component (A) described above.

[0222] In addition to the above-mentioned rubber component (C1), the cross-linked rubber composition of the fabric layer may further include a filler (C2). As the filler (C2), the fillers exemplified as fillers (C) for the compression rubber layer and the extension rubber layer may be used. Among the above-mentioned fillers, carbon black is preferred. The proportion of the filler (C3) is, for example, 5 to 80 parts by mass, preferably 10 to 70 parts by mass, more preferably 20 to 60 parts by mass, and more preferably 30 to 50 parts by mass relative to 100 parts by mass of the rubber component (C1).

[0223] In addition to the rubber component (C1), the cross-linked rubber composition of the fabric layer may contain other additives (C3). As other additives (C3), the additives exemplified as other additives (D) for the compression rubber layer and the extension rubber layer may be used, and preferably a cross-linking agent, a cross-linking accelerator, a processing agent or a processing aid, a plasticizer, an anti-aging agent, etc. may be used. The proportion of other additives (C3) may be selected from the same range as the proportion of additives (D) for the compression rubber layer and the extension rubber layer, including a preferred range.

[0224] The crosslinked rubber composition of the fabric layer has a rubber hardness Hs of, for example, 40 to 80°, preferably 50 to 70°, and more preferably 55 to 65°. The crosslinked rubber composition of the fabric layer has a tensile strength in the belt width direction of, for example, 5 to 30 MPa, preferably 10 to 25 MPa, and more preferably 15 to 20 MPa.

[0225] The fabric layer can be used alone (single layer) or in combination of two or more (in a laminated structure). The fabric layer is configured such that the outer peripheral surface (entire surface) of the fabric layer and the inner peripheral surface (entire surface) of the rubber layer containing short fibers are integrated (bonded) with each other, and the fabric layer and the rubber layer containing short fibers share the deformation stress applied to the strapping belt. The fabric layer can be configured such that the fabric layer only serves as an adhesive rubber (adhesive) for integrating the rubber layer containing short fibers with the V-belt portion of the wrap. If productivity and the like are also taken into consideration, the fabric layer is preferably used alone (single layer).

[0226] The average thickness of the fabric layer is, for example, about 0.4 mm to about 1.4 mm, preferably about 0.5 mm to about 1 mm. If the fabric layer is too thin, interlayer peeling and ring breakage may occur. On the contrary, if the fabric layer is too thick, the bendability of the belt may be reduced.

[0227] [Modifications]

[0228] The surface of each rib (particularly, two inclined surfaces on both sides of the rib that serve as friction transmission surfaces) may be covered with fabric (fibrous member such as woven fabric, knitted fabric, or nonwoven fabric).

[0229] <Method for manufacturing a combined V-belt>

[0230] The manufacturing method of the combined V-belt of the present invention comprises: a connecting step of connecting two or more cloth-wrapped V-belt precursors by using a strap precursor; a cross-linking molding step of heating and pressurizing the connected cloth-wrapped V-belt precursor and the strap precursor to perform cross-linking molding; and a rib forming step of forming a rib on the outer peripheral side of the obtained cross-linked molded body. Furthermore, in the manufacturing method of the combined V-belt of the present invention, as a pre-step of the connecting step, a first precursor forming step of manufacturing a cloth-wrapped V-belt precursor (uncross-linked cloth-wrapped V-belt portion) and a second precursor forming step of manufacturing a strap precursor (uncross-linked strap) may be included.

[0231] [First precursor forming step for manufacturing the wrap V-belt precursor]

[0232] The wrapper V-belt precursor (uncrosslinked wrapper V-belt) as the first precursor can be produced by the method described in, for example, Japanese Patent Application Laid-Open No. 6-137381 or International Publication No. 2015 / 104778.

[0233] As a representative manufacturing method, a method in which the compression rubber layer is a double-layer structure and includes a reinforcing cloth layer is described below. In the representative manufacturing method, a wrap V-belt precursor (uncrosslinked wrap V-belt) can be obtained through a winding step, a cutting step, a scraping step, and a cover rolling step.

[0234] In the winding process, a laminated body formed by laminating a reinforcing cloth layer fabric subjected to bonding treatment, a second compression rubber layer sheet obtained by calendering treatment and a first compression rubber layer sheet in this order is wound on a mandrel. Then, an uncrosslinked adhesive rubber layer sheet is wound around the periphery of the first compression rubber layer sheet. Then, a core body is wound around the periphery of the adhesive rubber layer sheet, and an uncrosslinked stretched rubber layer sheet is wound around the periphery of the core body to form an annular laminated body.

[0235] In the cutting step, the obtained annular laminate is cut on a mandrel (annular cutting).

[0236] In the skiving step, the cut annular laminate is placed on a pair of pulleys and cut into a V-shape while being rotated.

[0237] In the cover winding step, the obtained uncrosslinked tape main body is covered with an outer cover fabric precursor.

[0238] [Second precursor forming step for manufacturing the binding band precursor]

[0239] The strapping tape precursor (uncrosslinked strapping tape) as the second precursor was produced by the following production steps.

[0240] (Preparation of rubber layer precursor containing short fibers)

[0241] The short fiber-containing rubber layer precursor is formed through a sheet calendering step and a conditioning step.

[0242] In the sheet calendering step, the rubber composition containing the short fibers is kneaded using a Banbury mixer or the like, and the kneaded rubber is calendered using a calender roll or the like. Then, an uncrosslinked rubber sheet is prepared in which the short fibers are arranged (oriented) in the calendering direction.

[0243] In the adjustment step, the obtained uncrosslinked rubber sheet is adjusted to predetermined dimensions (length, width) and orientation direction required for the binding tape.

[0244] In this adjustment step, a sheet of a short fiber-containing rubber layer precursor (a short fiber-containing rubber layer in which the rubber component is in an uncrosslinked state) in which the short fibers are arranged in a direction parallel to the width direction of the rubber sheet can be obtained.

[0245] like Figure 1 As shown in Embodiment 1, when the binding belt is a combined V-belt formed only of a short-fiber-containing rubber layer, the short-fiber-containing rubber layer precursor is configured as a binding belt precursor.

[0246] (Preparation of a strapping tape precursor including a fabric layer)

[0247] The fabric layer precursor (the rubber component of the fabric layer sandwich rubber is an uncrosslinked fabric layer) constituting the strapping tape can be formed by laminating uncrosslinked fabric layer sandwich rubber sheets on both sides of a fabric (fiber structure) which can be subjected to a bonding treatment in advance. The strapping tape precursor can be formed by superimposing a rubber layer precursor sheet containing short fibers on the fabric layer precursor sheet (superimposing the sheet so that the extending direction of the first filaments forming the fiber structure and the arrangement direction of the short fibers are respectively in predetermined directions with respect to the width direction of the sheet).

[0248] [Step of connecting two or more V-belts with a binding band]

[0249] use Figure 8 and 9 The following is a typical process of connecting two or more V-belts with a strapping tape. Figure 8 As shown, in the device 60 for cross-linking molding, an uncross-linked annular body (a combination of a strapping belt precursor and two or more wrapping V-belt precursors) 61 held in a state of being wound around a pair of pulleys 64a, 64b is clamped between the pair of pulleys 64a, 64b by two pairs of pressing dies (a first pair of pressing dies formed by combining an inner peripheral side die 62a and an outer peripheral side die 62b, and a second pair of pressing dies formed by combining an inner peripheral side die 63a and an outer peripheral side die 63b). In detail, as Fig. 9As shown, a pair of pressing dies has a structure in which an inner circumference side die 73 having a groove portion with an inverted trapezoidal cross-section corresponding to the wrapped V-belt portion is combined with an outer circumference side die 74 having a flat plate-like surface opposite to the inner circumference side die 73. In the pair of pressing dies, two or more wrapped V-belt precursors 71 arranged in the width direction are inserted into the groove portion formed in the inner circumference side die 73, and then a binding belt precursor 72 is set on the outer circumference side thereof. At this time, the rubber layer precursor 72a containing short fibers is set in such a manner that the arrangement direction of the short fibers extends in the belt width direction. As shown in FIG. Fig. 9 When the fabric layer precursor 72b is included in this manner, the first filaments forming the fiber structure are provided so as to extend in a predetermined direction with respect to the tape width direction.

[0250] The thus arranged binding band precursor 72 and the two or more wrapping V-belt precursors 71 are subjected to a cross-linking molding step (vulcanization step) in which they are sandwiched between an outer peripheral side mold 74 and an inner peripheral side mold 73 and pressurized and heated.

[0251] [Cross-linking molding step of integrating the constituent members through the cross-linking reaction of the rubber component]

[0252] In the cross-linking molding step, the connected V-belt precursor and the binding belt precursor are formed into a predetermined shape by applying pressure and heat in the pressing die, and the rubber components contained in each component are integrated by a cross-linking reaction. Figure 8 In the process, a pair of pulleys 64a and 64b are rotated to move the uncrosslinked portion of the annular body 61 to the pressing die to crosslink the portion. When this operation is repeated so that the annular body 61 is crosslinked over the entire circumference, a crosslinked sleeve is formed in which two or more wrapped V-belt portions are connected and combined by the binding belt.

[0253] It should be noted that in the cross-linking molding process, the cross-linking temperature can be selected according to the type of rubber component, for example, 120 to 200° C., preferably 150 to 180° C. The pressure can be selected according to the type of rubber component, for example, 0.1 to 10 MPa, preferably 0.5 to 3 MPa, and more preferably 0.9 to 1.5 MPa. It should be noted that in the present application, the above pressure is a value converted into a pressing surface pressure.

[0254] [Rib forming step of forming a rib (predetermined rib shape) on the outer peripheral side of the belt]

[0255] like Fig.10As shown, a cross-linked sleeve in which two or more wrapped V-belt portions 81 are connected and joined by a binding belt 82 is wound between a pair of V-belt pulleys 83. Then, while the cross-linked sleeve is running under a certain tension, a grinding wheel (grinder) 84 having protrusions of a V-shaped cross section corresponding to two or more ribs arranged at a predetermined interval (interval) in the circumferential direction is rotated, and a predetermined rib shape is formed on the outer peripheral side of the cross-linked sleeve by grinding processing pressed against the outer peripheral surface of the cross-linked sleeve. It should be noted that at this time, whether the connection portion is formed by the minimum thickness portion (rib valley portion) of the binding belt or the connection portion is formed by the maximum thickness portion (rib peak portion) of the binding belt can be adjusted by using a combination of a grinding wheel and a V-belt pulley separately.

[0256] By cutting the cross-linked sleeve thus formed into a specified width, a combined V-belt having a specified number of wrapped V-belt portions and two or more (specified number) ribs with inverted V-shaped (trapezoidal) cross-sections on the back can be obtained.

[0257] Example

[0258] The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples. It should be noted that the following shows the details of the materials used in the examples, the method for preparing the uncrosslinked rubber sheet, and the methods for measuring or evaluating various physical properties.

[0259] [Raw materials of rubber composition]

[0260] Neoprene: "PM-40" manufactured by DENKA Corporation

[0261] Magnesium oxide: Kyowa Chemical Industry Co., Ltd. "Kiowa Mag 30"

[0262] Stearic acid: "Stearic acid tsubaki" manufactured by NOF Corporation

[0263] Anti-aging agent: "NonFruit OD-3" manufactured by Seiko Chemical Co., Ltd.

[0264] Carbon black: "Size 3" manufactured by Tokai Carbon Co., Ltd.

[0265] Silica: "ULTRASIL (registered trademark) VN3" manufactured by Evonik Japan Co., Ltd., BET specific surface area 175 m 2 / g

[0266] Plasticizer: ADEKA Corporation's "ADEKA SIZER RS-700"

[0267] Cross-linking accelerator: "Nokusela TT" manufactured by Ouchi Shinko Chemical Industry Co., Ltd.

[0268] Zinc oxide: "Zinc oxide 3 types" manufactured by Shodo Chemical Industry Co., Ltd.

[0269] Cycloparaffin oil: "NS-900" manufactured by Idemitsu Kosan Co., Ltd.

[0270] N,N'-m-phenylene dimaleimide: "Valnok PM" manufactured by Ouchi Shinko Chemical Industry Co., Ltd.

[0271] Aramid staple fibers: "Conex staple fibers" manufactured by Teijin Limited (short fibers having an average fiber length of 3 mm and an average fiber diameter of 14 μm, which were bonded with an RFL liquid [2.6 parts by mass of resorcinol, 1.4 parts by mass of 37% formalin, 17.2 parts by mass of vinylpyridine-styrene-butadiene copolymer latex (manufactured by Nippon Zeon Co., Ltd.), and 78.8 parts by mass of water], and having a solid content adhesion rate of 6%)

[0272] Polyester staple fiber: "Tetron" manufactured by Teijin Limited (average staple fiber length 3 mm)

[0273] Nylon staple fiber: "Nylon 66" manufactured by Asahi Kasei Corporation (average staple fiber length 6 mm)

[0274] Cotton staple fibers (average staple fiber length 6 mm, average fiber diameter 15 μm)

[0275] [Core Wire]

[0276] Aramid fiber twisted rope (average wire diameter 1.190mm)

[0277] [Rubber composition]

[0278] The rubber compositions A to G shown in Tables 2 and 3 were mixed with a Banbury mixer to prepare a block-shaped uncrosslinked rubber composition. The obtained uncrosslinked rubber composition was passed through a calendering roll to form a calendered rubber sheet of a predetermined thickness, thereby preparing an uncrosslinked rubber sheet for forming each rubber layer. Then, the results of measuring the hardness and tensile strength of the crosslinked product (crosslinked rubber) of each rubber composition are also shown in Tables 2 and 3.

[0279]

[0280] [Table 3]

[0281]

[0282] [Rubber hardness Hs of cross-linked rubber]

[0283] Each rubber layer was pressed and heated with an uncrosslinked rubber sheet at a temperature of 160°C for 30 minutes to prepare a crosslinked rubber sheet (100 mm×100 mm×2 mm thickness). The laminate formed by overlapping three crosslinked rubber sheets was used as a sample, and the hardness of the crosslinked rubber sheet was measured using a type A durometer according to the spring Shore hardness test specified in JIS K6253 (2012).

[0284] [Tensile strength of cross-linked rubber]

[0285] A cross-linked rubber sheet prepared for measuring the rubber hardness Hs of the cross-linked rubber was used as a sample, and a test piece punched into a dumbbell shape (No. 5 shape) was made according to JIS K6251 (2017). In the sample containing short fibers, a dumbbell-shaped test piece was cut in such a way that the arrangement direction of the short fibers (texture parallel direction) was the tensile direction. Then, both ends of the test piece were clamped with a chuck (clamp), and the maximum tensile force recorded when the test piece was stretched at a speed of 500 mm / min until it was cut was divided by the initial cross-sectional area of ​​the test piece, and the value obtained (tensile strength T) was used as the tensile strength.

[0286] [Outer cloth]

[0287] Woven fabric using polyester fiber and cotton blended yarn (polyester fiber / cotton = 50 / 50 mass ratio) (120° wide-angle weaving, 20-count warp yarn and 20-count weft yarn, warp and weft yarn density 75 yarns / 50mm, unit area weight 280g / m 2 ) and the rubber composition B of Table 2, and the rubber composition B and the woven fabric were simultaneously passed between rollers with different surface speeds of the calender rolls. Then, a rubbing treatment was performed by rubbing the rubber composition B between the meshes of the woven fabric (once for each of the front and back sides of the woven fabric) to prepare a precursor of the cover fabric (a woven fabric with rubber).

[0288] [Fabric layer]

[0289] On both sides of a cloth (fiber structure) having a structure shown in Table 4, uncrosslinked cloth layer sandwiching rubber sheets formed from rubber composition C in Table 2 were stacked and pressed with rollers to prepare a cloth layer precursor in which the cloth (fiber structure) was sandwiched between the sandwiching rubbers.

[0290] [Table 4]

[0291]

[0292] [Overview of each specimen]

[0293] The outline of each test piece (combined V-belt) is shown below according to the order of the test pieces described in Tables 9 to 18 of the verification results described later.

[0294] Example 1 (a form in which the compression rubber layer is a single layer, there is no fabric layer, and the connecting portion is formed by the rib valley portion)

[0295] (Production of the front body of the wrapped V-belt)

[0296] As the compression rubber layer sheet and the stretching rubber layer sheet, the rubber composition E in Table 3 was used. The compression rubber layer sheet and the adhesive rubber layer sheet (rubber composition A) were wound around the outer periphery of the mandrel in sequence. A core wire was spirally wound around the outer periphery, and then the stretching rubber layer sheet was wound in sequence to form an uncrosslinked annular laminate, and a wrapped V-belt precursor was produced by the method described in the above embodiment (without using a reinforcing cloth layer fabric).

[0297] (Production of strapping belt precursor)

[0298] As the short fiber-containing rubber layer sheet, the rubber composition F shown in Table 3 was used, and a short fiber-containing rubber layer precursor (thickness 4.6 mm) was prepared by the method described in the above embodiment, and this was used as a binding band precursor.

[0299] (Manufacturing of combined V-belts)

[0300] exist Figure 8 In the device for cross-linking molding shown, 6 cloth-wrapped V-belt precursors and binding belt precursors are provided, and by the method described in the above embodiment, they are pressurized to 1.2 MPa and heated at a temperature of 160°C to produce a cross-linked sleeve in which 6 cloth-wrapped V-belts [ARPM A type, cross-sectional dimensions: width (W1) 13.2 mm × thickness (H1) 8.4 mm, belt length 122 inches] are connected by binding belts. Then, by grinding, a prescribed rib shape (type A shown in Table 1, H and d are numerical values ​​in parentheses) is formed on the outer peripheral side of the cross-linked sleeve. It should be noted that at this time, the connecting portion of the binding belt is formed by the rib valley portion (the minimum thickness portion of the binding belt). The obtained cross-linked sleeve is cut to produce a combined V-belt (having Figure 1 The dimensions of the obtained combined V-belt are: belt width (W) of 29.1 mm, belt thickness (H) of 13.0 mm, and belt length of 122 inches.

[0301] Example 2 (a mode in which the compression rubber layer is a single layer and does not have a fabric layer, and the connecting portion is formed by a rib peak portion)

[0302] In the step of forming a predetermined rib shape on the outer peripheral side of the cross-linked sleeve by grinding, a combined V-belt (having a V-belt having ... Figure 3It should be noted that the dimensions (width, thickness, length) of the obtained combined V-belt are also the same as those of Example 1.

[0303] Example 3 (Form in which the compression rubber layer is double-layered and does not have a fabric layer, and the connecting portion is formed by the rib valley portion)

[0304] A combined V-belt having two wrapped V-belt portions was produced by the same method as in Example 1 except that the compression rubber layer was double-layered, the rubber composition E was used for the second compression rubber layer sheet, and the rubber composition D having a relatively high hardness was used for the first compression rubber layer sheet and the extension rubber layer sheet. It should be noted that the dimensions (width, thickness, length) of the obtained combined V-belt were also the same as those in Example 1.

[0305] Example 4 (Form in which the compression rubber layer is double-layered and does not have a fabric layer, and the connecting portion is formed by a rib peak portion)

[0306] In the step of forming a predetermined rib shape on the outer peripheral side of the cross-linked sleeve by grinding, the connecting portion was changed to be formed by the rib peak portion (the maximum thickness portion of the binding belt), and a combined V-belt having two wrapped V-belt portions was produced in the same manner as in Example 3. It should be noted that the dimensions (width, thickness, length) of the obtained combined V-belt were also the same as those in Example 3.

[0307] Example 5 (Form in which the compression rubber layer is a single layer and has a fabric layer, and the connecting portion is formed by the rib valley portion)

[0308] The calendered sheet of the rubber sandwiched between the fabric layers and the fabric A (cord) were simultaneously passed between rollers of which the surface speeds of the calendering rollers were approximately the same. Then, the front and back sides of the cord were laminated (once for each of the front and back sides of the cord) by burying the cord in the rubber sandwiched between the fabric layers (rubber composition C) to prepare a sheet of rubber-attached cord (thickness 0.7 mm) as a fabric layer precursor.

[0309] Next, in the preparation of the strap precursor, a combined V-belt (having a thickness of 3.9 mm) having two wrapped V-belt portions was prepared in the same manner as in Example 1 except that a sheet (thickness: 3.2 mm) obtained by laminating a short fiber-containing rubber layer precursor and a fabric layer precursor was used as the strap precursor. Figure 2 The dimensions of the obtained combined V-belt were: belt width (W) of 29.1 mm, belt thickness (H) of 12.3 mm, and belt length of 122 inches.

[0310] Example 6 (a mode in which the compression rubber layer is a single layer and has a fabric layer, and the connecting portion is formed by a rib peak portion)

[0311] In the step of forming a predetermined rib shape on the outer peripheral side of the cross-linked sleeve by grinding, a combined V-belt (having a V-belt having ... Figure 4 It should be noted that the dimensions (width, thickness, length) of the obtained combined V-belt are also the same as those of Example 5.

[0312] Example 7 (Form in which the compression rubber layer is double-layered and has a fabric layer, and the connecting portion is formed by the rib valley portion)

[0313] A combined V-belt having two wrapped V-belt portions was produced by the same method as in Example 5 except that the compression rubber layer was double-layered, the rubber composition E was used for the second compression rubber layer sheet, and the rubber composition D having a relatively high hardness was used for the first compression rubber layer sheet and the extension rubber layer sheet. It should be noted that the dimensions (width, thickness, length) of the obtained combined V-belt were also the same as those in Example 5.

[0314] Example 8 (Form in which the compression rubber layer is double-layered and has a fabric layer, and the connecting portion is formed by a rib peak portion)

[0315] In the step of forming a predetermined rib shape on the outer peripheral side of the cross-linked sleeve by grinding, the connection portion was changed to be formed by the rib peak portion (the maximum thickness portion of the binding belt), and a combined V-belt having two wrapped V-belt portions was produced in the same manner as in Example 7. It should be noted that the dimensions (width, thickness, length) of the obtained combined V-belt were also the same as those in Example 7.

[0316] Comparative Example 1 (Form in which the compression rubber layer is a single layer and the binding band is formed of a flat fabric layer)

[0317] In the preparation of the strap precursor, a woven fabric with rubber (fabric type: fabric B) used as the precursor of the above-mentioned outer cover was used as the strap precursor. Then, when two or more cover V-belt precursors and the strap precursor were set in a pressing mold, the yarns constituting the woven fabric in the strap precursor were set in a manner such that the direction of the yarns was inclined relative to the belt width direction (the warp yarns and the weft yarns were 30 degrees relative to the belt width direction, that is, the yarns of both sides were symmetrical relative to the belt length direction) and the grinding process for forming a predetermined rib shape was not performed on the outer peripheral side of the belt. A combined V-belt (conventionally used combined V-belt) having two cover V-belt parts was prepared in the same manner as in Example 1. The dimensions of the obtained combined V-belt were a belt width (W) of 29.1 mm, a belt thickness (H) of 9.1 mm, and a belt length of 122 inches.

[0318] Comparative Example 2 (Form in which the compression rubber layer is double-layered and the binding band is formed of a flat cloth layer)

[0319] A combined V-belt having two wrapped V-belt portions was produced in the same manner as in Comparative Example 1, except that the compression rubber layer was double-layered, the rubber composition E was used for the second compression rubber layer sheet, and the rubber composition D having a relatively high hardness was used for the first compression rubber layer sheet and the extension rubber layer sheet. It should be noted that the dimensions (width, thickness, length) of the obtained combined V-belt were also the same as those in Comparative Example 1.

[0320] Comparative Example 3 (Form in which the compression rubber layer is a single layer and the binding band is formed of a flat short fiber-containing rubber layer)

[0321] A combined V-belt having two wrapped V-belt portions was produced in the same manner as in Example 1 except that the thickness of the calendered sheet was changed so that the finished thickness of the short fiber-containing rubber layer precursor was 2.1 mm and that the grinding process for forming a predetermined rib shape was not performed on the outer peripheral side of the belt. Figure 1 The dimensions of the obtained combined V-belt were: a belt width (W) of 29.1 mm, a belt thickness (H) of 10.5 mm, and a belt length of 122 inches.

[0322] Comparative Example 4 (Form in which the compression rubber layer is double-layered and the binding band is formed of a flat short-fiber-containing rubber layer)

[0323] A combined V-belt having two wrapped V-belt portions was produced in the same manner as in Comparative Example 3 except that the compression rubber layer was double-layered, the rubber composition E was used for the second compression rubber layer sheet, and the rubber composition D having a relatively high hardness was used for the first compression rubber layer sheet and the extension rubber layer sheet. It should be noted that the dimensions (width, thickness, length) of the obtained combined V-belt were also the same as those of Comparative Example 3.

[0324] Comparative Example 5 (Form in which the compression rubber layer is a single layer and the binding tape is formed of a laminate of a flat fabric layer and a flat short fiber-containing rubber layer)

[0325] A combined V-belt having two wrapped V-belt portions was prepared in the same manner as in Example 5 except that the binding belt precursor was a sheet (thickness: 2.1 mm) formed by laminating a rubber layer precursor (thickness: 1.4 mm) containing short fibers and a fabric layer precursor containing fabric A (cord), and that the outer peripheral side of the belt was not ground to form a predetermined rib shape. Figure 2 The dimensions of the obtained combined V-belt were: a belt width (W) of 29.1 mm, a belt thickness (H) of 10.5 mm, and a belt length of 122 inches.

[0326] Comparative Example 6 (Form in which the compression rubber layer is double-layered and the binding tape is formed of a laminate of a flat fabric layer and a flat short fiber-containing rubber layer)

[0327] A combined V-belt having two wrapped V-belt portions was produced in the same manner as in Comparative Example 5, except that the compression rubber layer was double-layered, the rubber composition E was used for the second compression rubber layer sheet, and the rubber composition D having a relatively high hardness was used for the first compression rubber layer sheet and the extension rubber layer sheet. It should be noted that the dimensions (width, thickness, length) of the obtained combined V-belt were also the same as those of Comparative Example 5.

[0328] Examples 9 to 12

[0329] The rib height H2 (and thus the thickness H3 of the entire strapping belt) was changed as shown in Tables 11 and 12 (gradually thinner), and the combined V-belts having two wrapped V-belt parts were produced in the same manner as in Example 8. It should be noted that the dimensions (width, thickness, length) of each combined V-belt obtained were the same as those of Example 8 except for the belt thickness H.

[0330] Embodiments 13 to 15

[0331] The rib height H2 (and thus the thickness H3 of the entire strapping belt) was changed as shown in Tables 11 and 12 (gradually thicker), and the combined V-belts having two wrapped V-belt parts were produced in the same manner as in Example 4. It should be noted that the dimensions (width, thickness, length) of each combined V-belt obtained were the same as those of Example 4 except for the belt thickness H.

[0332] Examples 17 to 20

[0333] The arrangement pitch P2 of the ribs was changed as shown in Tables 13 and 14, and the combined V-belts having two wrapped V-belts were produced in the same manner as in Example 8. It should be noted that the dimensions (width, thickness, length) of each combined V-belt obtained were the same as those of Example 8 except for the rib shape (peaks, valleys) at the connecting portion.

[0334] Example 16

[0335] A combined V-belt having two wrapped V-belt portions was produced in the same manner as in Example 17 except that the rib height H2 (and thus the thickness H3 of the entire strapping belt) was changed as shown in Tables 13 and 14. It should be noted that the dimensions (width, thickness, length) of the obtained combined V-belt were the same as those of Example 17 except for the belt thickness H.

[0336] Embodiment 21

[0337] A combined V-belt having two wrapped V-belt portions was produced in the same manner as in Example 20 except that the cloth layer was changed to a non-cloth layer and the rib height H2 (and thus the thickness H3 of the entire strapping belt) was changed as shown in Tables 13 and 14. It should be noted that the dimensions (width, thickness, length) of the obtained combined V-belt were the same as those of Example 20 except for the belt thickness H.

[0338] Example 22, Comparative Example 7

[0339] Including the presence or absence of the short fiber-containing rubber layer constituting the strapping belt, the type of the rubber composition constituting the rubber layer of the strapping belt was changed as shown in Tables 15 and 16, and a combined V-belt having two wrapped V-belt portions was produced in the same manner as in Example 8. The dimensions (width, thickness, length) of each combined V-belt obtained were also the same as in Example 8.

[0340] Comparative Example 8

[0341] A combined V-belt having two wrapped V-belt portions was produced in the same manner as in Example 4 except that the type of the rubber composition constituting the rubber layer of the strapping belt was changed to the rubber composition E not containing short fibers as shown in Tables 15 and 16, including the presence or absence of the short fiber-containing rubber layer constituting the strapping belt. The dimensions (width, thickness, length) of the obtained combined V-belt were also the same as those in Example 4.

[0342] Embodiment 23

[0343] A combined V-belt having two cloth-wrapped V-belt portions was produced in the same manner as in Example 8 except that the type of fabric constituting the fabric layer was changed to a plain woven fabric (fabric C) as shown in Tables 17 and 18. It should be noted that, as for the fabric layer precursor, a sheet of rubberized plain woven fabric (thickness 0.7 mm) was prepared by the same method as in Example 5, and this was used as the fabric layer precursor. In addition, in the production of the combined V-belt, the direction of the yarns constituting the fabric (fabric C) was arranged to be inclined relative to the belt width direction (the warp and weft yarns were 30° relative to the belt width direction, that is, the yarns of both sides were symmetrical relative to the belt length direction). The dimensions (width, thickness, length) of the obtained combined V-belt were also the same as those in Example 8.

[0344] [Evaluation of combined V-belts: items, methods, and criteria]

[0345] For each of the test pieces shown in Tables 9 to 18, the transmission performance (slip ratio) and durability performance of the belt back surface were verified in order to confirm whether a combined V-belt that can solve the present problem was obtained.

[0346] [Transmission performance (slip ratio)]

[0347] (Test name) Transmission performance (slip ratio) measurement test

[0348] (Testing machine)

[0349] In the experiment, use Fig.11 The multi-axis layout of the multi-axis traveling testing machine is shown.

[0350] In this test machine, the pulleys of the layout consisting of the driving pulley (Dr1), the driven pulleys (Dn2 and Dn3), the tension pulley (Ten4) and the idler pulley (ID5) shown in Table 5 are arranged in the order of the driving pulley (Dr1) 91, the tension pulley (Ten4) 94, the driven pulley (Dn3) 93, the driven pulley (Dn2) 92, and the idler pulley (ID5) 95. This test machine is capable of confirming the transmission performance (slip ratio) and the durability performance (presence or absence of belt failure) under various conditions (load, etc.).

[0351] [Table 5]

[0352]

[0353] (Test method)

[0354] The combined V-belts of each test piece were run under the load shown in Table 6 (9.5 kW applied to the driven pulley Dn2, 23.0 kW applied to the driven pulley Dn3, a total of 32.5 kW) before and after the running to evaluate the durability performance described later. Then, the speed (rpm) of the driven pulley (back driven pulley) Dn2 was measured, and the slip ratio was calculated according to the following formula. It should be noted that the speeds of the driving pulley Dr1 and the driven pulley Dn2 when there is no load in the measurement, and the speed of the driving pulley Dr1 when there is a load are shown in Table 7.

[0355] Slip rate (%) = [(K2-K1) / K1] × 100

[0356] [In the formula, K1=R1 / N1, K2=R2 / N2, R1 represents the speed of the driving pulley during no-load operation (rpm), N1 represents the speed of the driven pulley during no-load operation (rpm), R2 represents the speed of the driving pulley during load operation (rpm), and N2 represents the speed of the driven pulley during load operation (rpm)]

[0357] [Table 6]

[0358]

[0359] [Table 7]

[0360]

[0361] (Judgment Criteria)

[0362] Whether double-sided transmission can be performed with high performance can be determined from the perspective of how much the transmission performance on the belt outer peripheral side (back side) is improved compared with the wrapped V-belts (Comparative Examples 1 and 2) whose belt outer peripheral surface (back side) is formed flat.

[0363] As a judgment of the transmission performance of the outer peripheral side (back side) of the belt, the slip ratio between the friction transmission surface on the outer peripheral side of the belt and the back driven pulley Dn2 is used as an index [the smaller the slip ratio, the better the transmission performance of the outer peripheral side (back side) of the belt, and the more high-performance double-sided transmission can be performed].

[0364] The slip rate value [the larger value before and after running (before running, after 240 hours of running)] (%):

[0365] If the percentage is less than 0.5%, it is judged as a.

[0366] If the rate is more than 0.5% and less than 0.6%, it is judged as b.

[0367] If the value is more than 0.6% and less than 0.7%, it is judged as c.

[0368] The case exceeding 0.7% is judged as d.

[0369] From the perspective of suitability for actual use (transmission performance of the belt back side of the combined V-belt) in this application (a combined V-belt requiring double-sided drive), any of the belts in judgments a to c is considered to be acceptable.

[0370] [Durability]

[0371] (Test name) Durability test

[0372] (Testing machine)

[0373] In the test, the same multi-axis running tester as in the above-mentioned durability transmission performance (slip ratio) measurement test was used.

[0374] (Test method)

[0375] The combined V-belts of each test piece were run for 240 hours under the conditions shown in Table 8. The belts were visually observed over time, and the presence or absence of abnormalities such as cracking and peeling, and the time until the belts broke were evaluated according to the following criteria. It should be noted that the load during running was applied to the driven pulley (back driven pulley) Dn2 (9.5 kW) and the driven pulley Dn3 (23.0 kW), with a total load of 32.5 kW, as shown in Table 6. It should be noted that in Examples 1 to 23 and Comparative Examples 7 to 8, V-belt pulleys were used for Dr1 and Dn3, V-ribbed pulleys were used for Dn2, and flat pulleys were used for Ten4 and ID5. In Comparative Examples 1 to 6, V-belt pulleys were used for Dr1 and Dn3, and flat pulleys were used for Dn2, Ten4, and ID5.

[0376] [Table 8]

[0377]

[0378] (Judgment Criteria)

[0379] As a judgment of the durability of each belt,

[0380] The case where the 240-hour durability test can be carried out and no abnormalities such as cracks and peeling are found is set as judgment a;

[0381] The case where the 240-hour durability test can be carried out and some abnormalities such as cracks and peeling are observed (to a degree that does not affect the performance of the combined V-belt) is regarded as judgment b;

[0382] The case where the endurance running time is 200 hours or more and less than 240 hours and abnormalities (cracks, peeling) of a degree that hinders the performance of the combined V-belt occur is set as c judgment;

[0383] The case where the endurance running time is less than 200 hours and abnormality (cracks, peeling) occurs to the extent that the performance of the combined V-belt is impaired is regarded as judgment d.

[0384] It should be noted that the “durable running time” refers to the time during which the durability performance test was conducted.

[0385] From the perspective of suitability for actual use (durability of the combined V-belt) in this application (a combined V-belt requiring double-sided drive), any of the belts in the evaluations a to c is considered to be acceptable.

[0386] (Comprehensive judgment)

[0387] As a criterion for comprehensive evaluation (grading) of the combined V-belt that can solve the present problem, based on the evaluation results of the above two evaluation items (transmission performance (slip ratio), durability performance), a grade of C or higher is regarded as acceptable as follows.

[0388] Rank A: When all the above evaluation items are judged as a, it is judged that there is no problem at all in practical use and it is set to the best rank.

[0389] Level B: When there is no c judgment in the above evaluation items but there is one b judgment, there is no problem in practical use and it is set to a slightly worse level.

[0390] Level C: If there is no d decision in the above evaluation items but there is one c decision, there is no problem in practical use and the level is set to be slightly worse than level B.

[0391] Level D: If at least one of the above evaluation items is judged as d, it is set to a level that is not enough to solve the problem (failure).

[0392] [Verification results]

[0393] Tables 9 to 18 show the results of evaluating the combined V-belts obtained by the above tests.

[0394]

[0395]

[0396] (Examples 1 to 8, Comparative Examples 1 to 6)

[0397] The V-belts of Examples 1 to 8 did not show any significant abnormality before the end time of 240 hours in the above durability test and completed the test. It was found that the method of providing a high-hardness rubber layer on the core layer side in the compression rubber layer, as in Examples 3, 4, 7, and 8, has an effect on durability (especially the durability of the V-belt portion).

[0398] Furthermore, it was found that the method in which the connecting portion is formed by the maximum thickness portion (rib crest portion) of the binding band as in Examples 2, 4, 6, and 8 also has an effect on durability (particularly the durability of the connecting portion).

[0399] Furthermore, it was found that the binding tape having a fabric layer including a fiber structure (cord) on the inner peripheral side of the tape as in Examples 5 to 8 also has an effect on durability (particularly the durability of the connecting portion and the binding tape other than the connecting portion).

[0400] On the other hand, in the combined V-belts of Comparative Examples 1 to 6 in which the back side of the belt is formed into a flat shape (flat), except for Comparative Example 1 (the conventionally used cloth-wrapped combined V-belt), no significant abnormalities were found before the above-mentioned cut-off time, and the running was completed (the durability performance was judged as a or b). Regarding the transmission performance (slip rate), in the method (Comparative Example 2) in which the outer peripheral side (back side) of the belt is formed by a cloth layer (woven fabric with rubber), it was 1.00% before durable running and 1.30% after durable running, which was judged as d (the overall judgment was also grade D). In the method (Comparative Examples 3 to 6) in which the outer peripheral side (back side) of the belt is formed by a rubber layer containing short fibers, it was 0.60% before durable running and 0.71 to 0.73% after durable running, which was judged as d (the overall judgment was also grade D).

[0401] In contrast, the transmission performance (slip rate) of the combined V-belts of Examples 1 to 8 was 0.40% before the endurance running and 0.48 to 0.52% after the endurance running (a judgment), which is a judgment or b judgment (comprehensive judgment is also grade A or grade B). That is, compared with the cloth-wrapped combined V-belt in which the back of the belt is formed to be flat, it can be said that the combined V-belt formed in a manner that the back of the belt includes two or more ribs suppresses the slip rate on the outer peripheral side (back side) of the belt, and the transmission performance is improved. Therefore, it can be said that the connected combined V-belt having an inverted V-shaped side surface (friction transmission surface) that can contact the V-rib pulley not only on the inner peripheral side but also on the outer peripheral side can perform double-sided transmission with high performance and can perform high-capacity transmission.

[0402]

[0403]

[0404] (Examples 8 to 12)

[0405] The belt of Example 8 (a double-layer compression rubber layer, a fabric layer, a connecting portion formed by rib peaks, and an arrangement pitch of ribs of 3.975 mm) was used as the base, in which the length ratios in the belt thickness direction, H2 / H1, were 0.30 and H3 / H1, were 0.46. The rib height was changed to 2.5 mm for comparison.

[0406] As the rib height (H2) decreases, the slip rate of the belt back surface tends to increase. In Example 10, the rib height was reduced to 1.1 mm, and as a result, the ratio (H2 / H1) of the rib height (H2) to the thickness (H1) of the wrapping V-belt portion was reduced to 0.13, and the ratio (H3 / H1) of the thickness (H3) of the strapping band to the thickness (H1) of the wrapping V-belt portion was reduced to 0.30. The transmission performance (slip rate) of the acceptable level (b judgment) was ensured, and the grade was B. In Example 9, the rib height was further reduced to 0.9 mm, H2 / H1 was reduced to 0.11, and H3 / H1 was reduced to 0.27, and the transmission performance (slip rate) of the acceptable level was ensured, and the grade was C.

[0407] (Examples 8, 13 to 15)

[0408] The belt of Example 8 (the compression rubber layer is a double layer, the connecting portion is formed by rib peaks, and the arrangement pitch of the ribs is 3.975 mm) with a length ratio of H2 / H1 of 0.30 and H3 / H1 of 0.46 in the belt thickness direction was used as a base, and the structure was changed to a structure without a cloth layer in the strapping belt (a structure in which the thickness of the strapping belt was further increased), and the rib height was changed to 2.5 mm for comparison.

[0409] As the rib height (H2) increases, the following tendency is observed: although the slip rate on the back side of the belt decreases, cracks are easily introduced in the ribs, possibly due to the decrease in bending resistance, and the durability performance decreases. In Example 14, the rib height is increased to 2.9 mm for Example 8, and as a result, the ratio (H2 / H1) of the rib height (H2) to the thickness (H1) of the wrapping V-belt portion increases to 0.35, and the ratio (H3 / H1) of the thickness (H3) of the strapping band to the thickness (H1) of the wrapping V-belt portion increases to 0.60. The durability performance of the passing level (b judgment) is ensured, and the grade is B. In Example 15, the rib height is further increased to 3.8 mm for Example 8, H2 / H1 is increased to 0.45, and H3 / H1 is increased to 0.70. Although the durability performance of the passing level is ensured (c judgment), it is slightly worse than that of Example 14, and the durability performance of the passing level (c judgment) is ensured, and the grade is C.

[0410] [Table 13]

[0411]

[0412] [Table 14]

[0413]

[0414] (Examples 8, 17-18)

[0415] The belt of Example 8 (double-layer compression rubber layer, cloth layer, connecting part formed by rib peaks, rib height 2.5 mm) in which the arrangement pitch ratio (P1 / P2) of the cloth-wrapped V-belt part to the ribs is 4 is used as the base, and the arrangement pitch of the ribs is changed to 3.975 mm for comparison.

[0416] As the rib arrangement pitch (P2) increases, the slip rate of the belt back side tends to increase. In Example 18, the rib arrangement pitch is increased to 10.6 mm, and as a result, the ratio of the arrangement pitch of the wrap V-belt portion to the rib (P1 / P2) is reduced to 1.5. The transmission performance (slip rate) of the qualified level can be ensured (b judgment), and the grade is B. In Example 17, the rib arrangement pitch is further increased to 15.9 mm and P1 / P2 is reduced to 1, which is slightly worse than Example 18, but the transmission performance (slip rate) of the qualified level can be ensured (c judgment), and the grade is C.

[0417] (Examples 8, 19-20)

[0418] The belt of Example 8 (double-layer compression rubber layer, cloth layer, connecting part formed by rib peaks, rib height 2.5 mm) in which the arrangement pitch ratio (P1 / P2) of the cloth-wrapped V-belt part to the ribs is 4 is used as the base, and the arrangement pitch of the ribs is changed to 3.975 mm for comparison.

[0419] When the arrangement pitch (P2) of the ribs becomes smaller, the following tendency is found: although the slip rate on the back side of the belt decreases, cracks are easily introduced in the ribs, which may be due to the decrease in lateral pressure resistance, and the durability performance decreases. In addition, in Example 19, the arrangement pitch of the ribs is reduced to 2.271 mm with the result that the arrangement pitch ratio (P1 / P2) of the wrap V-belt portion to the ribs is increased to 7, and the durability performance (b judgment) of the qualified level can be ensured, and the grade is B. In Example 20, the arrangement pitch of the ribs is further reduced to 1.988 mm and P1 / P2 is increased to 8 for Example 8, the transmission performance (slip rate) of the qualified level can be ensured (c judgment) and the grade is C.

[0420] (Examples 16 and 21)

[0421] Example 16 is an example in which the transmission performance (slip ratio) is near the lower limit, and is an example in which the rib height H2 of 0.9 mm, which is the lowest (slip ratio is the highest) in Examples 8 to 15, and the rib arrangement pitch P2 of 15.9 mm, which is the highest (slip ratio is the highest) in Examples 8 and 17 to 20. As with Examples 9 and 17, the durability performance is determined as a, but the transmission performance (slip ratio) is determined as c, which is a critical pass level, and is grade C.

[0422] Example 21 is an example in which the durability performance is near the lower limit, and is an example in which the rib height H2 of Examples 8 to 15 is the highest (durability performance is the worst) of 3.8 mm and the rib arrangement pitch P2 of Examples 8 and 17 to 20 is the smallest (durability performance is the worst) of 1.988 mm. As with Examples 15 and 20, the transmission performance (slip ratio) is determined as a, but the durability performance is determined as c, which is a critical pass level, and is grade C.

[0423] (Summary of the results in Tables 11 to 14)

[0424] As in Example 16, by providing a V-shaped groove on the outer peripheral surface of the belt that can contact the V-shaped side surface (friction transmission surface) of the back driven pulley (V-rib pulley), even if their contact area is small (rib height 0.9mm, rib arrangement pitch 15.9mm), the slip rate of the outer peripheral surface (back side) of the belt can be effectively suppressed (no excessive slip), and the transmission performance (slip rate) can be ensured. It can be confirmed that the result is that double-sided drive can be effectively performed.

[0425] On the other hand, in the configuration where the contact area between the V-shaped side surface (friction transmission surface) of the back driven pulley (V-rib pulley) and the cross-sectional V-shaped groove becomes larger (the rib height is increased and the arrangement pitch of the ribs is reduced), there is a concern that the durability performance may be reduced due to cracks introduced into the ribs. However, even the configuration of Example 21 (rib height 3.8 mm, rib arrangement pitch 1.988 mm) can be confirmed to be effective in ensuring durability.

[0426] Based on the results in Tables 11 to 14, it can be said that in a wide range of combinations of rib height H2 (0.9 to 3.8 mm) and rib arrangement spacing P2 (1.988 to 15.9 mm), it is possible to achieve both qualified level transmission performance (slip rate) and durability performance effective for double-sided drive.

[0427] In addition, considering that the ratio of the rib height (H2) to the thickness of the wrapped V-belt portion (H1), which is the length ratio in the belt thickness direction (H2 / H1), is about 0.11 to about 0.45, the ratio of the thickness of the strapping belt (H3) to the thickness of the wrapped V-belt portion (H1) (H3 / H1) is about 0.27 to about 0.7, and the arrangement pitch ratio (P1 / P2) of the wrapped V-belt portion to the rib is about 1 to about 8, it can be said that both the transmission performance (slip rate) and the durability performance at a qualified level effective for double-sided drive can be achieved.

[0428] In particular, the ranges of H2 / H1 of about 0.13 to about 0.35, H3 / H1 of about 0.3 to about 0.6, and P1 / P2 of about 1.5 to about 7 are preferable from the viewpoint of the balance between the transmission performance (slip ratio) and the durability performance.

[0429]

[0430]

[0431] (Examples 8, 22, Comparative Examples 7, 8)

[0432] The belt of Example 8 (compression rubber layer is double-layered, has a cloth layer, connecting portion is formed by rib peak portion, rib height is 2.5 mm, rib arrangement pitch is 3.975 mm) in which the type of rubber composition constituting the short fiber-containing rubber layer of the strapping tape is rubber composition F was used as a base, and the type of rubber composition constituting the rubber layer of the strapping tape was changed, including the presence or absence of the short fiber-containing rubber layer, for comparison.

[0433] In Example 22 of the strapping belt having a structure in which the ratio of short fibers and the type of short fibers are different from those in Example 8 and a rubber layer (rubber composition G) containing short fibers is laminated on the outer peripheral surface of a fabric layer, the belt performance [transmission performance (slip rate), durability performance] of the qualified level can be ensured equally with Example 8, and the comprehensive judgment is grade A.

[0434] On the other hand, in Comparative Example 7 of the strapping tape having a structure in which a rubber layer (rubber composition E) not containing short fibers is laminated on the outer peripheral surface of the fabric layer, the transmission performance (slip rate) of the back side of the tape was judged as c. However, the durable running time was less than 200 Hr and cracks occurred in the ribs, the durability performance was judged as d, and the overall judgment was grade D.

[0435] In addition, in Comparative Example 8, which has a strapping tape without a fabric layer and composed only of a rubber layer (rubber composition E) without short fibers, the transmission performance (slip rate) of the back side of the belt is also judged as c, compared with Example 8, in which the strapping tape has no fabric layer. However, the durable running time is less than 200 hours and interlayer peeling occurs between the strapping tape portion and the wrapped V-belt portion, so the durability is judged as d, and the overall judgment is grade D.

[0436] Based on the above results, it can be said that the binding belt formed by a rubber layer containing short fibers and a fabric layer containing a fiber structure laminated on the inner side of the belt of the rubber layer containing short fibers is preferred in terms of having the effect of ensuring the belt performance [transmission performance (slip rate), durability performance] of the qualified level.

[0437] [Table 17]

[0438]

[0439] [Table 18]

[0440]

[0441] (Examples 4, 8, 23)

[0442] The strapping tape of Example 8 (the compressed rubber layer is a double layer, the connecting portion is formed by rib peaks, the rib height is 2.5 mm, and the rib arrangement pitch is 3.975 mm) is used as the base, in which a fabric layer comprising a fabric (fiber structure) as a curtain fabric (fabric A) and a rubber layer containing short fibers are formed. The type of fabric constituting the fabric layer of the strapping tape is changed, including the presence or absence of the fabric layer, for comparison.

[0443] In Example 23 in which the type of fabric constituting the fabric layer is a plain fabric (fabric C), the transmission performance (slip rate) on the back side of the belt was judged as b, probably due to slightly reduced bending properties compared to Example 8 in which the fabric was a cord fabric (fabric A), and the durability performance was also observed to have some interlayer peeling (to a degree that did not hinder the performance of the coupled V-belt) and was judged as b (the overall judgment was also grade B).

[0444] In Example 4, in which the strapping tape is composed only of a rubber layer containing short fibers (rubber composition F) and has no fabric layer, as described above, the transmission performance (slip rate) on the back side of the tape is judged as a, which is equivalent to Example 8, and the durability performance is judged as b (some cracks are generated in the ribs), and the overall judgment is also grade B.

[0445] Based on the above results, it can be said that although it is not necessary for the strapping belt to include a fabric layer, the fabric (fiber structure) in the fabric layer formed by the cord (fabric A) is preferred in terms of having the effect of more reliably ensuring the belt performance [transmission performance (slip rate), durability performance] of the qualified level.

[0446] Based on all the above verification results, it can be confirmed that the transmission performance (slip ratio) and durability performance (capable of high-performance double-sided transmission and high-capacity transmission) of the qualified level effective for double-sided drive can be achieved by the binding belt at least on the outer peripheral side (back side) of the belt containing a short fiber-containing rubber layer in which the short fibers are oriented in the belt width direction, and the short fiber-containing rubber layer has two or more ribs extending in the belt length direction. The above two performances cannot be achieved by a wrapped V-belt whose back side is formed flat or a V-belt whose back side is formed to include two or more ribs but does not contain short fibers in the rubber composition constituting the rubber layer of the binding belt.

[0447] The present invention is described in detail and with reference to specific embodiments, but it is obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention. This application is based on Japanese patent applications (Japanese patent application 2022-121172) filed on July 29, 2022 and Japanese patent applications (Japanese patent application 2023-120314) filed on July 24, 2023, the contents of which are incorporated herein by reference.

[0448] Industrial Applicability

[0449] The combined V-belt of the present invention can be used as various friction transmission belts requiring double-sided drive, and can be used for general industrial machinery such as compressors, generators, pumps, etc.; fiber machinery such as spinning machines, textile machines, looms, knitting machines, dyeing and finishing machines, etc.; agricultural machinery such as tillers, rice transplanters, vegetable transplanters, transplanters, reapers, combine harvesters, bean harvesters, corn crushers, potato harvesters, beet harvesters, vegetable harvesters, mowers, threshers, rice mills, rice mills, etc. Among them, it is suitable for high-load and large agricultural machinery used in Europe and the United States, such as tillers, reapers, combine harvesters, vegetable harvesters, threshers, bean harvesters, corn crushers, potato harvesters, beet harvesters, etc.

[0450] Explanation of symbols

[0451] 1…Combined V-belt

[0452] 2…Cloth-wrapped V-belt

[0453] 3…Extended rubber layer

[0454] 4…Core layer

[0455] 4a…Core

[0456] 5…Compression rubber layer

[0457] 6…Outer cloth

[0458] 7…Straps

[0459] 7a…ribs

[0460] 7b…Short fibers

Claims

1. A combined V-belt comprising two or more cloth-wrapped V-belt portions and a binding belt, wherein: The outer peripheral surfaces of each V-belt portion are connected by the binding belt. Each wrapper V-belt portion includes a belt body and an outer wrapper covering the outer surface of the belt body. The belt body includes a core layer including a core, a stretch rubber layer laminated on the belt outer peripheral side of the core layer, and a compression rubber layer laminated on the belt inner peripheral side of the core layer. The strapping belt comprises a rubber layer containing short fibers, wherein the short fibers are oriented in the width direction of the belt. The short fiber-containing rubber layer has two or more ribs extending in the belt length direction.

2. The combined V-belt according to claim 1, wherein: The arrangement pitch of the ribs is smaller than the arrangement pitch of the wrapping V-belt portions.

3. The combined V-belt according to claim 1 or 2, wherein: The arrangement pitch of the ribs is greater than the width of the gap between adjacent wrapping V-belt portions.

4. The combined V-belt according to any one of claims 1 to 3, wherein: The strapping tape comprises the short fiber-containing rubber layer and a fabric layer. The fabric layer includes a fiber structure laminated on the inner peripheral surface of the short fiber-containing rubber layer.

5. The combined V-belt according to claim 4, wherein: The fiber structure is a cord fabric including two or more first filaments extending in the belt width direction and two or more second filaments extending in a direction intersecting the belt width direction. The arrangement density of the second filaments is smaller than the arrangement density of the first filaments.

6. The combined V-belt according to any one of claims 1 to 5, wherein: The top center of the rib is located in the gap between adjacent wrapping V-belt parts.

7. The combined V-belt according to any one of claims 1 to 6, wherein: The thickness of the binding belt is 0.3 to 0.7 times the thickness of the cloth-wrapped V-belt portion.

8. The method for manufacturing a combined V-belt according to any one of claims 1 to 7, comprising: A connecting step of connecting two or more cloth-wrapped V-belt precursors using a strapping belt precursor; A cross-linking molding step of heating and pressurizing the connected wrapping V-belt precursor and the binding belt precursor to perform cross-linking molding; as well as A rib forming step is a step of forming a rib on the outer peripheral side of the obtained cross-linked shaped body.

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