JP2019019980A - Wrapped v-belt - Google Patents

Abstract

To provide a wrapped V-belt capable of preventing occurrence of a crack and excellent in durability.SOLUTION: A wrapped V-belt is an endless wrapped V-belt, and has, as shown in Fig.7, an endless rubber layer 5, an outside cloth 3 covering the whole rubber layer 5, and a high-strength fiber sheet 4. One sheet of outside cloth 3 is wound around the rubber layer 5 so that a circumferential direction of the rubber layer 5 is consistent with a longitudinal direction of the outside cloth 3. The high-strength fiber sheet 4 is wound around a boundary portion of the outside cloth 3.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a wrapped V-belt in which a friction transmission surface is covered with a covering cloth.

  The friction transmission belt, which has a V-shaped cross section and transmits power by friction transmission, covers the low-edge V-belt, which is a rubber layer with exposed friction transmission surfaces on both sides in the belt width direction, and the friction transmission surface. There is a Wrapped V-belt covered with a cloth, which is properly used depending on the application due to the difference in surface properties (friction coefficient) of the friction transmission surface. These friction transmission belts are used in a wide range of fields such as automobiles and industrial machines.

  Patent Document 1 discloses a wrapped V-belt in which a rubber layer is covered with a jacket cloth. Although there is no particular description in Patent Document 1, as shown in FIGS. 8 and 9, in a general endless wrapped V-belt 101, the circumferential direction of the rubber layer 105 and the longitudinal direction of the jacket cloth 103 coincide with each other. As described above, one outer cover 103 is wound, and the entire endless rubber layer 105 is covered with the outer cover 103. Further, in order to reliably cover the rubber layer 105, the winding start end portion 113a and the winding end end portion 113b of the covering fabric 103 are arranged so as to overlap each other in the belt circumferential direction.

JP 2010-125725 A

  The conventional wrapped V-belt 101 shown in FIGS. 8 and 9 has an overlapping portion 111 in which the winding start end portion 113a and the winding end end portion 113b overlap each other in the belt circumferential direction. . Since the object in which the winding start end portion 113a and the winding end end portion 113b are overlapped and wound in the belt circumferential direction is a three-dimensional rubber layer 105, particularly in the overlapping portion 111, It is difficult to wind the cloth 103 with high accuracy, and the thickness of the belt locally increases. Therefore, in this portion, the belt is difficult to bend and the bending stress is high. Accordingly, the temperature of the rubber layer 105 is likely to rise due to the self-heating caused by the bending in the portion where the covering cloth 103 overlaps. As a result, the rubber layer 105 loses elasticity and becomes hard, and there is a problem that cracks are likely to occur. When this crack progresses to the vicinity of the core line, or when a plurality of cracks are combined to grow into a large crack, the rubber layer 105 may be peeled off from the core line. Further, in the portion where the crack is generated in the rubber layer 105, the cover cloth 103 may be cracked. Further, in the overlapping portion 111 of the outer covering cloth 103, the outer covering cloth 103 may be cracked before the rubber layer 105. And it is not preferable from the viewpoint of durability (life) of the belt that the rubber layer 105 and the covering cloth 103 are easily cracked in the overlapping portion 111 of the covering cloth 103.

  In particular, due to the recent decrease in pulley diameter and diversification of functions, the wrapped V-belt is subject to an increase in driven shaft, high load, high tension, running for a long time, and the bending angle of the reverse bending pulley is large and the reverse bending is severe. But it is increasingly used. Therefore, there is a further need for a wrapped V-belt that does not easily crack even under severe bending conditions.

  Accordingly, an object of the present invention is to provide a wrapped V-belt that is less likely to crack and has excellent durability.

  An endless wrapped V-belt comprising an endless rubber layer, a core wire embedded in the rubber layer, and a single outer covering covering the rubber layer, the circumferential direction of the rubber layer and the outer covering The covering cloth is wound around the entire rubber layer so that the longitudinal directions of the covering cloths coincide with each other, and a boundary portion between the winding start end and the winding end end adjacent to the belt circumferential direction of the covering cloth is 2 A high-strength fiber sheet having a structure in which fiber bundles extending in the direction intersect is wound so as to commonly cover the winding start end portion and the winding end end portion of the jacket cloth. In the present invention, the “boundary portion of the outer covering cloth” refers to the case where the end portion of the outer covering cloth overlaps the end portion of the winding end and the end portion of the outer covering cloth and the end of the winding end. Including both cases where the end portions are arranged with a gap.

  According to the above configuration, since the high-strength fiber sheet is wound around the rubber layer so as to cover the entire boundary portion of the jacket cloth, the rubber layer and the jacket cloth are hardly cracked at the boundary portion. Even if a crack occurs in the rubber layer, the outer cover cloth is reinforced with a high-strength fiber sheet, so that the outer cover cloth is not easily torn. Therefore, the durability of the belt is improved.

  The winding start end portion and the winding end end portion of the jacket cloth are arranged with a gap therebetween so as not to overlap each other in the belt circumferential direction, and at the boundary portion, the high-strength fiber sheet is formed of the jacket cloth. The gap is covered with the winding start end and the winding end end overlapping each other.

  According to said structure, the edge part of the winding start of a jacket cloth and the edge part of winding end do not overlap. Therefore, since the belt thickness at the boundary portion does not have to be so thick, cracks hardly occur at the boundary portion.

  In the present invention, the high-strength fiber sheet is preferably thinner than the jacket cloth.

  Since the high-strength fiber sheet is thinner than the jacket cloth, even if the high-strength fiber sheet is stacked on the boundary portion of the jacket cloth, the amount of increase in the belt thickness is small. Therefore, the high-strength fiber sheets are not overlapped so that cracks are not easily generated at the boundary portion. On the other hand, since the boundary portion is reinforced by the thin and strong high-strength fiber sheet, the occurrence of cracks in the boundary portion can be reliably suppressed.

  In the present invention, the high-strength fiber sheet is preferably made of aramid fibers.

In the present invention, when the high-strength fiber sheet is composed of aramid fibers, the basis weight of the high-strength fiber sheet is preferably 90 to 870 g / m ² .

In this invention, when the said high strength fiber sheet consists of an aramid fiber, it is preferable that the tensile strength of the said high strength fiber sheet is 2060 N / mm < ² > or more.

  In this invention, when the said high strength fiber sheet consists of an aramid fiber, it is preferable that the thickness of the said high strength fiber sheet is 0.03-0.24 mm.

  In the present invention, the high-strength fiber sheet is preferably made of carbon fibers.

In the present invention, when the high-strength fiber sheet is made of carbon fiber, the basis weight of the high-strength fiber sheet is preferably 200 to 300 g / m ² .

In the present invention, when the high-strength fiber sheet is made of carbon fiber, the tensile strength of the high-strength fiber sheet is preferably 2900 N / mm ² or more.

  In this invention, when the said high strength fiber sheet consists of carbon fiber, it is preferable that the thickness of the said high strength fiber sheet is 0.05-0.09 mm.

  In the present invention, the high-strength fiber sheet is disposed so that two directions where the fiber bundles intersect each other are inclined with respect to the belt circumferential direction and the belt width direction.

  According to said structure, a wrapped V belt becomes easy to bend in a boundary part, it can suppress that a crack generate | occur | produces in a belt in a boundary part, and can improve durability more.

  In the present invention, the rubber layer comprises a compression rubber layer, an extension rubber layer, an adhesive rubber layer disposed between the compression rubber layer and the extension rubber layer, and a core wire embedded in the adhesive rubber layer. You may have.

  In the present invention, it is preferable that the surface on the rubber layer side of the high-strength fiber sheet is subjected to an adhesion treatment for improving the adhesion with the rubber layer.

  In the present invention, the belt width is preferably 13 to 70 mm, and the belt thickness is preferably 5 to 25 mm.

  As described in the above description, according to the present invention, it is possible to provide a wrapped V-belt that is less likely to crack and has excellent durability.

1 is an overall view of a wrapped V belt according to an embodiment of the present invention. It is a perspective view of the boundary part of the wrapped V belt concerning the embodiment of the present invention. It is a perspective view of the boundary part of the wrapped V belt before a high strength fiber sheet is wound. It is a top view of the jacket cloth before a cut. It is a top view of the jacket cloth before winding after cutting. It is a top view of the high strength fiber sheet before cutting. It is a perspective view of the boundary part of the wrapped V belt concerning the modification of the present invention. In the conventional wrapped V belt, it is a perspective view which shows the boundary part of the state by which a jacket cloth is wound. It is a perspective view which shows the boundary part of the conventional wrapped V belt around which the jacket cloth was wound. It is explanatory drawing of the wrapped V belt of Examples 1-4. It is explanatory drawing of the wrapped V belt of a comparative example. It is a schematic block diagram of the belt system of an Example and a comparative example.

[Configuration of Wrapped V Belt 1]
Next, the wrapped V-belt 1 according to the embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 2, the wrapped V-belt 1 includes an endless belt body 2, an outer covering 3 that covers the entire belt body 2, and a high-strength fiber sheet 4.

[Details of belt body 2]
The endless belt body 2 includes an endless rubber layer 5 and a core wire 6 embedded in the rubber layer 5. The rubber layer 5 includes a compressed rubber layer 8 inside the belt, an extended rubber layer 9 outside the belt, and an adhesive rubber layer 7 provided between the compressed rubber layer 8 and the extended rubber layer 9. A core wire 6 is embedded in the adhesive rubber layer 7. The compressed rubber layer 8 is compressed in the belt circumferential direction when it is run around a pulley. The stretch rubber layer 9 is stretched in the belt circumferential direction when it is run around a pulley. The thickness of the compressed rubber layer 8 is larger than the thickness of the stretched rubber layer 9.

  The adhesive rubber layer 7, the compressed rubber layer 8, and the stretch rubber layer 9 are composed of a rubber composition. The rubber composition constituting the adhesive rubber layer 7 is different from the rubber composition constituting the compressed rubber layer 8 and the rubber composition constituting the stretched rubber layer 9. The rubber composition constituting the adhesive rubber layer 7 has higher adhesion to the core wire 6 than the rubber composition constituting the compressed rubber layer 8 and the rubber composition constituting the stretched rubber layer 9. The rubber composition constituting the stretched rubber layer 9 and the rubber composition constituting the compressed rubber layer 8 may be the same or different.

  As the rubber component of the rubber composition, vulcanizable or crosslinkable rubber is used. Specifically, for example, diene rubber (natural rubber, isoprene rubber, butadiene rubber, chloroprene rubber, styrene butadiene rubber, acrylonitrile butadiene rubber, hydrogenated nitrile rubber, etc.), ethylene-α-olefin elastomer, chlorosulfonated polyethylene rubber Alkylated chlorosulfonated polyethylene rubber, epichlorohydrin rubber, acrylic rubber, silicone rubber, urethane rubber, fluorinated rubber and the like. These rubber components can be used alone or in combination of two or more.

  The rubber composition may include a vulcanizing agent or a crosslinking agent, a co-crosslinking agent, a vulcanization aid, a vulcanization accelerator, a vulcanization retarder, a metal oxide (zinc oxide, magnesium oxide, calcium oxide, Barium oxide, iron oxide, copper oxide, titanium oxide, aluminum oxide, etc.), reinforcing agent (carbon black, silicon oxide such as hydrous silica), short fiber, filler (clay, calcium carbonate, talc, mica, etc.), softening Agents (paraffin oil, oils such as naphthenic oil), processing agents or processing aids (stearic acid, metal stearate, wax, paraffin, etc.), anti-aging agents (antioxidants, thermal anti-aging agents, bending) Anti-cracking agent, anti-ozone degradation agent, etc.), colorant, tackifier, plasticizer, coupling agent (silane coupling agent, etc.), stabilizer (ultraviolet absorber, heat stabilizer, etc.), flame retardant, antistatic It may be formulated and the like. In addition, you may mix | blend a metal oxide as a crosslinking agent.

  The rubber composition constituting the stretched rubber layer 9 and the compressed rubber layer 8 may contain short fibers. The rubber composition constituting the adhesive rubber layer 7 does not contain short fibers.

  The core wire 6 extends in the belt circumferential direction, and is buried at a certain interval in the belt width direction. The core 6 is made of a twisted cord (multi-twisted, single twisted, rank twisted, etc.) using a multifilament yarn. The material of the core wire 6 is, for example, a synthetic fiber such as an aramid fiber or an inorganic fiber such as a carbon fiber. The core 6 may be subjected to an adhesion treatment with an RFL liquid or the like for the purpose of enhancing the adhesion with the adhesive rubber layer 7.

[Details of outer covering 3]
Examples of the fiber constituting the outer cover cloth 3 include polyethylene terephthalate of polyalkylene arylate fiber such as polyethylene fiber of polyolefin fiber, polypropylene fiber, polyamide 6 fiber of polyamide fiber, polyamide 66 fiber, polyamide 46 fiber, aramid fiber, etc. (PET) fiber, poly C2-4 alkylene C6-14 arylate fiber such as polyethylene naphthalate (PEN) fiber, vinyl alcohol fiber, polyvinyl alcohol, ethylene-vinyl alcohol copolymer fiber, vinylon fiber, etc. Synthetic fibers such as polyparaphenylene benzobisoxazole (PBO) fibers, cellulose fibers, natural fibers such as wool, and inorganic fibers such as carbon fibers are widely used. The fibers constituting the covering fabric 3 may be single yarns using these fibers alone, or may be a blended yarn combining two or more kinds.

  The jacket cloth 3 is a plain woven cloth in which the intersecting angle between the warp and the weft is a right angle. It may be a plain woven fabric (wide angle canvas) having a wide angle such that the intersection angle between the warp and the weft is greater than 90 ° and not more than 120 °. In addition, examples of the type of cloth of the jacket cloth 3 include woven cloth, knitted cloth (weft knitted cloth, warp knitted cloth), and non-woven cloth woven in a form such as twill weave and satin weave.

  The density of the warp and weft of the jacket cloth 3 is, for example, about 60 to 100 pieces / 50 mm, preferably about 70 to 90 pieces / 50 mm, and more preferably about 75 to 85 pieces / 50 mm. Moreover, the thickness of a jacket cloth is 0.4-2 mm, for example, Preferably it is 0.5-1.4 mm, More preferably, it is 0.6-1.2 mm.

  As shown in FIG. 4, a plurality of jacket fabrics 3 made of plain woven fabrics having a right angle of warp and weft crossing, preferably obliquely 45 ° with respect to the warp and weft along the cut line 14. Cut it. If necessary, a plurality of parallelogram-shaped outer cover cloths 3 formed by cutting are connected together so that a length suitable for covering the belt main body 2 is obtained. Thereafter, the outer covering cloth 3 is cut in parallel with the longitudinal direction of the outer covering cloth 3 so as to have an appropriate width for covering the belt body 2, thereby obtaining a plurality of covering cloths 3. One of the plurality of jacket cloths 3 is shown in FIG. As shown in FIG. 3, one outer cover cloth 3 is wound around the belt body 2 so that the circumferential direction of the rubber layer 5 and the longitudinal direction of the outer cover cloth 3 coincide with each other. The covering cloth 3 is overlapped on the bottom surface which is the inner surface of the belt. The covering cloth 3 is wound around the gap 12 so that the winding start end 13a and the winding end end 13b adjacent to each other in the belt circumferential direction of the covering cloth 3 do not overlap each other. In the following description, the portion including the winding start end portion 13a, the winding end end portion 13b, and the gap 12 adjacent to each other in the belt circumferential direction of the covering cloth 3 is referred to as a boundary portion 10 of the covering cloth 3. The jacket 3 is wound so that the angle formed by the warp with the belt circumferential direction and the angle formed by the weft with the belt width direction are both 45 °. The jacket 3 may be wound so that the angle formed by the warp with the belt circumferential direction and the angle formed by the weft with the belt width direction are both angles other than 45 °.

[Details of high-strength fiber sheet 4]
The high-strength fiber sheet 4 has a structure in which fiber bundles extending in two directions intersect. As shown in FIG. 6, the high-strength fiber sheet 4 is woven with a plurality of first fiber bundles 4a and a plurality of second fiber bundles 4b orthogonal to the first fiber bundle 4a. In addition, the 1st fiber bundle 4a and the 2nd fiber bundle 4b do not need to orthogonally cross.

The fiber bundle is composed of, for example, high-strength fibers such as aramid fibers and carbon fibers. The fibers constituting the first fiber bundle 4a and the second fiber bundle 4b are made of the same material. Each fiber bundle has a configuration in which a plurality of filaments (long fibers) are aligned. The tensile strength in the orientation direction of the first fiber bundle 4a and the orientation direction of the second fiber bundle 4b of the high-strength fiber sheet 4 is preferably, for example, 2000 N / mm ² or more. When the fiber bundle is an aramid fiber, for example, it is 2060 N / mm ² or more, and when the fiber bundle is a carbon fiber, it is, for example, 2900 N / mm ² or more. The basis weight of the high-strength fiber sheet 4 is, for example, 90 to 870 g / m ² when the fiber bundle is an aramid fiber, and is 200 to 300 g / m ² when the fiber bundle is a carbon fiber, for example. The thickness of the high-strength fiber sheet 4 is thinner than the thickness of the jacket cloth 3. By using the high-strength fiber sheet 4 that is thinner than the jacket cloth 3, even if the high-strength fiber sheet 4 is stacked on the boundary portion 10 of the jacket cloth 3, the amount of increase in the belt thickness is small. For this reason, the boundary portion 10 is not easily cracked by overlapping the high-strength fiber sheets 4. The thickness of the high-strength fiber sheet 4 is, for example, 0.03 to 0.24 mm when the fiber bundle is an aramid fiber, and is 0.05 to 0.09 mm, for example, when the fiber bundle is a carbon fiber. The fibers constituting the first fiber bundle 4a and the second fiber bundle 4b may be made of different materials.

  The high-strength fiber sheet 4 may be subjected to an adhesive treatment for enhancing the adhesiveness between the rubber layer 5 and the covering cloth 3. The adhesion treatment may be RFL treatment in which the high-strength fiber sheet 4 or the fibers constituting the high-strength fiber sheet 4 is immersed in an RFL solution, or an impregnation resin treatment in which the fibers are immersed in a resin solution. The RFL liquid is obtained by mixing an initial condensate of resorcin and formalin into a latex. Examples of the latex used here include styrene / butadiene / pyridine terpolymer, hydrogenated nitrile rubber, chlorosulfonated polyethylene, epichlorohydrin. Such as latex. The resin solution used for the impregnation resin treatment is, for example, an isocyanate solution or an epoxy solution. After the impregnation resin treatment, an adhesion treatment using an RFL liquid treatment may be performed. Further, as an adhesion treatment, an unvulcanized rubber composition dissolved in a solvent to form a rubber paste is applied to the surface of the high-strength fiber sheet 4, and then the solvent is evaporated to the surface of the high-strength fiber sheet 4. You may perform the rubber paste process which forms the film | membrane of an unvulcanized rubber composition. Further, after the adhesion treatment using the RFL liquid, rubber paste treatment may be performed.

  The high-strength fiber sheet 4 is preferably cut at an angle of 45 ° with respect to the first fiber bundle 4a and the second fiber bundle 4b. Here, the width of the gap 12 in the belt circumferential direction is W1, the width of the high-strength fiber sheet 4 in the belt circumferential direction is W2, and the width of the portion where the outer cover cloth 3 and the high-strength fiber sheet 4 overlap in the belt circumferential direction is W3. Keep it as The high-strength fiber sheet 4 is cut so that W3 falls within the range of 12.5% to 37.5% of W2. Thereby, the high-strength fiber sheet 4 and the covering fabric 3 can be sufficiently bonded without causing any trouble in the bending of the belt. As shown in FIGS. 1 and 2, the high-strength fiber sheet 4 is wound so as to cover the entire boundary portion 10 of the jacket cloth 3. That is, the high-strength fiber sheet 4 is wound so as to cover the winding start end portion 13 a and the winding end end portion 13 b that are adjacent to each other in the belt circumferential direction of the jacket cloth 3. At this time, the area where the high-strength fiber sheet 4 and the end portion 13a of the covering cloth 3 overlap is overlapped with the area where the high-strength fiber sheet 4 and the end portion 13b of the covering end of the covering 3 overlap. Wrapped. The high-strength fiber sheet 4 is preferably wound so that the angle formed by the first fiber bundle 4a with the belt circumferential direction and the angle formed by the second fiber bundle 4b with the belt width direction are both 45 °. At this time, the warp and weft of the jacket cloth 3 are the same as the directions of the first fiber bundle 4a and the second fiber bundle 4b of the high-strength fiber sheet 4. The high-strength fiber sheet 4 may be wound so that the angle formed by the first fiber bundle 4a with the belt circumferential direction and the angle formed by the second fiber bundle 4b with the belt width direction are both angles other than 45 °.

  The above-described wrapped V-belt 1 is manufactured as follows, for example. First, as described above, the jacket cloth 3 is cut obliquely with respect to the warp and the weft. Then, as shown in FIG. 3, one outer cover cloth 3 is wound around the belt main body 2 including the rubber layer 5 and the core wire 6 so that the circumferential direction of the rubber layer 5 and the longitudinal direction of the outer cover cloth 3 coincide with each other. . The covering cloth 3 is overlapped on the bottom surface which is the inner surface of the belt. At this time, the covering cloth 3 is wound around the gap 12 so that the winding start end 13a and the winding end end 13b adjacent to each other in the belt circumferential direction of the covering cloth 3 do not overlap each other. The jacket 3 is wound so that the angle formed by the warp with the belt circumferential direction and the angle formed by the weft with the belt width direction are both 45 °. The jacket 3 may be wound so that the angle formed by the warp with the belt circumferential direction and the angle formed by the weft with the belt width direction are both angles other than 45 °.

  Next, the high-strength fiber sheet 4 is cut obliquely with respect to the first fiber bundle 4a and the second fiber bundle 4b as described above. As shown in FIGS. 1 and 2, the high-strength fiber sheet 4 is wound so as to cover the entire boundary portion 10 of the jacket cloth 3. That is, the high-strength fiber sheet 4 is wound so as to cover the winding start end portion 13 a and the winding end end portion 13 b that are adjacent to each other in the belt circumferential direction of the jacket 3. At this time, the area where the high-strength fiber sheet 4 and the end portion 13a of the covering cloth 3 overlap is overlapped with the area where the high-strength fiber sheet 4 and the end portion 13b of the covering end of the covering 3 overlap. Wrap. The high-strength fiber sheet 4 is wound so that the angle formed by the first fiber bundle 4a with the belt circumferential direction and the angle formed by the second fiber bundle 4b with the belt width direction are both 45 °. That is, the warp and the weft of the jacket cloth 3 are the same as the directions of the first fiber bundle 4a and the second fiber bundle 4b of the high-strength fiber sheet 4. The high-strength fiber sheet 4 may be wound so that the angle formed by the first fiber bundle 4a with the belt circumferential direction and the angle formed by the second fiber bundle 4b with the belt width direction are both angles other than 45 °.

  Since the high-strength fiber sheet 4 is wound around the rubber layer 5 so as to cover the entire boundary portion of the outer cover cloth 3, the rubber layer 5 and the outer cover cloth 3 are hardly cracked at the boundary portion. Even if the rubber layer 5 is cracked, the outer cover cloth 3 is reinforced by the high-strength fiber sheet 4, and therefore the outer cover cloth 3 is hardly broken. Therefore, the durability of the belt is improved.

  Since the winding start end portion 13a and the winding end end portion 13b of the covering cloth 3 do not overlap with each other at the boundary portion 10 of the covering cloth 3, the belt thickness at the boundary portion 10 does not become so much thick. This makes it difficult to crack.

  Since the high-strength fiber sheet 4 is thinner than the jacket cloth 3, even if the high-strength fiber sheet 4 is stacked on the boundary portion 10 of the jacket cloth 3, the amount of increase in the belt thickness is slight. For this reason, the boundary portion 10 is not easily cracked by overlapping the high-strength fiber sheets 4. On the other hand, since the boundary portion 10 is reinforced by the thin and strong high-strength fiber sheet 4, the occurrence of cracks in the boundary portion 10 can be reliably suppressed.

  The high-strength fiber sheet 4 is preferably made of aramid fibers.

When the high-strength fiber sheet 4 is made of aramid fibers, the basis weight of the high-strength fiber sheet 4 is preferably 90 to 870 g / m ² .

When the high-strength fiber sheet 4 is composed of aramid fibers, the tensile strength of the high-strength fiber sheet 4 is preferably 2060 N / mm ² or more.

  When the high-strength fiber sheet 4 is made of aramid fibers, the thickness of the high-strength fiber sheet 4 is preferably 0.03 to 0.24 mm.

  The high-strength fiber sheet 4 is preferably made of carbon fiber.

When the high-strength fiber sheet 4 is made of carbon fiber, the basis weight of the high-strength fiber sheet 4 is preferably 200 to 300 g / m ² .

When the high-strength fiber sheet 4 is made of carbon fiber, the tensile strength of the high-strength fiber sheet 4 is preferably 2900 N / mm ² or more.

  When the high strength fiber sheet 4 is made of carbon fiber, the thickness of the high strength fiber sheet 4 is preferably 0.05 to 0.09 mm.

  The high-strength fiber sheet 4 is arranged so that two directions where the fiber bundles intersect are inclined with respect to the belt circumferential direction and the belt width direction. The wrapped V-belt 1 can be easily bent at the boundary portion 10, and the belt can be prevented from cracking at the boundary portion 10, and the durability can be further improved.

  The rubber layer 5 includes a compression rubber layer 8, an extension rubber layer 9, an adhesive rubber layer 7 disposed between the compression rubber layer 8 and the extension rubber layer 9, and a core wire 6 embedded in the adhesive rubber layer 7. , May be included.

  The surface on the rubber layer 5 side of the high-strength fiber sheet 4 is preferably subjected to an adhesion treatment for improving the adhesion with the rubber layer 5.

  It is preferable that the belt width is 13 to 70 mm and the belt thickness is 5 to 25 mm.

(Examples and Comparative Examples)
Next, the wrapped V belts of Examples 1 to 4 and the comparative example were produced. The belts of Examples 1 to 4 are the wrapped V belt 1 of the above embodiment. The belt of the comparative example is the conventional wrapped V-belt 101. Examples 1 to 4 and the wrapped V-belt of the comparative example use the same rubber layer and core wire of the belt body. The specifications are the same for the outer covering.

(Specifications of wrapped V-belt)
The rubber compositions used for the rubber layers of the belts of Examples 1 to 4 and Comparative Example are shown in Table 1 below. The friction rubber is a rubber composition for the friction processing of the outer cover cloth described later.

クロロプレンゴムとしてＤＥＮＫＡ（株）製のＰＭ−４０を、酸化マグネシウムとして協和化学工業（株）製のキョーワマグ３０を、ステアリン酸として日油（株）製のステアリン酸つばきを、老化防止剤として精工化学（株）製のノンフレックスＯＤ−３を、カーボンブラックとして東海カーボン（株）製のシースト３を、可塑剤としてＡＤＥＫＡ（株）製のＲＳ−７００を、加硫促進剤として大内新興化学工業（株）製のノクセラーＴＴを、酸化亜鉛として正同化学工業（株）製の酸化亜鉛３種を使用した。

Seiko Chemical Co., Ltd. uses PM-40 manufactured by DENKA Corporation as chloroprene rubber, Kyowamag 30 manufactured by Kyowa Chemical Industry Co., Ltd. as magnesium oxide, and stearic acid camellia manufactured by NOF Corporation as stearic acid. Non-flex OD-3 manufactured by Tokai Carbon Co., Ltd. as carbon black, RS-700 manufactured by ADEKA Co., Ltd. as plasticizer, and Ouchi Shinsei Chemical Industry as vulcanization accelerator Noxeller TT manufactured by Co., Ltd. was used, and three types of zinc oxide manufactured by Shodo Chemical Industry Co., Ltd. were used as zinc oxide.

  The core wire is a twisted cord of polyester fiber, and the average wire diameter is 1.518 mm.

The jacket fabric is a plain woven cotton fabric. The fineness of the warp and the weft is both 20th, and the density of the warp and the weft is 75/50 mm. The basis weight of the covering fabric is 280 g / m ² . The outer cover cloth is subjected to friction processing once for each of the front surface and the rear surface, and friction rubber is rubbed between the fibers of the outer cover cloth. The friction process is a process in which a calendar roll is used, the friction rubber and the fabric are simultaneously passed between rolls having different surface speeds, and the friction rubber is rubbed between the fibers of the fabric.

  As shown in FIG. 10A, in the wrapped V-belt 1 of Examples 1 to 4, a gap 12 is provided between the winding start end portion 13a and the winding end end portion 13b of the jacket cloth 3, and the gap 12 and the winding belt 1 are wound. The high-strength fiber sheet 4 formed of high-strength fibers such as aramid fibers or carbon fibers is wound so as to cover the boundary portion 10 including the start end portion 13a and the end end portion 13b. On the other hand, as shown in FIG. 10B, in the wrapped V-belt 101 of the comparative example, the outer covering cloth 103 is wound so that the end portion 113a at the start of winding and the end portion 113b at the end of winding overlap. Further, in the belt 101 of the comparative example, the overlapping portion 111 of the outer covering cloth 103 is not covered with the high-strength fiber sheet.

  In Examples 1 to 4, high-strength fiber sheets 4 having different specifications were used. Table 2 below shows the specifications of the high-strength fiber sheets 4 of Examples 1 to 4.

  Table 3 below shows the dimensions of the wrapped V-belts of Examples 1 to 4 and the comparative example. As shown in FIG. 10B, W4 is the width in the belt circumferential direction of the overlapping portion 111 in the wrapped V-belt 101 of the comparative example.

(Durability test)
Next, durability tests of the wrapped V belts of Examples 1 to 4 and the comparative example were performed. In particular, the impact resistance under reverse bending conditions with a tension pulley was verified. As shown in FIG. 11, a durability test was performed with a belt system 16 including a wrapped V belt, a drive pulley 17 (Dr), a driven pulley 18 (Dn), and a tension pulley 19 (Ten). The driving pulley 17 and the driven pulley 18 are formed with V grooves that can be engaged with the wrapped V belt. The wrapped V-belt is wound around the driving pulley 17 and the driven pulley 18 so that each V groove of the driving pulley 17 and the driven pulley 18 contacts the side surface of the wrapped V-belt. The tension pulley 19 is a flat pulley and can come into contact with the outer peripheral surface of the wrapped V-belt. The tension pulley 19 functions as a clutch in the belt system 16. When the tension pulley 19 applies tension to the belt, power transmission is started (clutch ON state), and when the belt tension is relaxed, power transmission is interrupted (clutch OFF state).

  The test conditions for the durability test are shown in Table 4 below. The “load” is a load torque applied to the drive pulley 17 and is calculated by multiplying the radius of the drive pulley 17 by the power transmitted from the wrapped V belt to the drive pulley 17. The Ten load is a force that the wrapped V-belt receives from the tension pulley 19 when the clutch is ON.

  In the durability test, in the belt 1 of Examples 1 to 4, cracks occurred in the overlapping portion 15 of the high-strength fiber sheet 4 and the covering cloth 3 as shown in FIG. 10A. On the other hand, as shown in FIG. 10B, in the belt 101 of the comparative example, a crack occurred in the overlapped portion 111 of the jacket cloth 103. Table 5 shows the results of measuring the time until the occurrence of each crack.

  In the durability test, with the wrapped V-belt reversely bent by the tension pulley 19, the tension pulley 19 is intermittently moved toward and away from the belt to apply an impact to the belt. Under such severe traveling conditions, in the belt 101 of the comparative example, a crack occurred in the overlapped portion 111 of the covering fabric 103 in the traveling time of 32 hours. On the other hand, in the belts 1 of Examples 1 to 4 using the high-strength fiber sheet 4, the running time until cracks occurred was 5 to 10 times that of the belt 101 of the comparative example. Thereby, it turned out that the belt 1 of Examples 1-4 is excellent in the impact resistance under reverse bending conditions.

(1) In the above-described embodiment, the high-strength fiber sheet 4 has both the angle formed by the first fiber bundle 4a with the belt circumferential direction and the angle formed by the second fiber bundle 4b with the belt width direction. Although it is wound so as to be 45 °, the angle formed by the first fiber bundle 4a with the belt circumferential direction and the angle formed by the second fiber bundle 4b with the belt width direction are both wound so as to be 60 °. Also good. This may effectively suppress the occurrence of cracks in the wrapped V-belt.

(2) In the above-described embodiment, the winding start end 13a and the winding end 13b that are adjacent to each other in the belt circumferential direction of the jacket 3 are arranged with a gap 12 therebetween so as not to overlap each other. However, as shown in FIG. 7, there may be an overlapping portion 11 in which the winding start end portion 13 a and the winding end end portion 13 b adjacent to each other in the belt circumferential direction of the jacket cloth 3 overlap each other. Thereby, the belt thickness at the boundary portion is larger than that in the embodiment. However, even in this case, since the high-strength fiber sheet 4 is superimposed on the boundary portion, the occurrence of cracks at the boundary portion is suppressed.

DESCRIPTION OF SYMBOLS 1 Wrapped V belt 2 Belt body 3 Cover cloth 4 High-strength fiber sheet 5 Rubber layer 6 Core wire 7 Adhesive rubber layer 8 Compressed rubber layer 9 Stretched rubber layer 10 Boundary portion 12 Gap 13a Winding end 13b Winding end

Claims (15)

An endless wrapped V-belt comprising an endless rubber layer, a core wire embedded in the rubber layer, and one outer covering covering the rubber layer,
The outer cover cloth is wound around the entire rubber layer so that the circumferential direction of the rubber layer and the longitudinal direction of the outer cover cloth coincide with each other,
A high-strength fiber sheet having a structure in which fiber bundles extending in two directions intersect at a boundary portion between a winding start end and a winding end end adjacent to the belt circumferential direction of the jacket cloth, A wrapped V-belt, wherein the wrapped V-belt is wound so as to cover a winding start end and the winding end end in common. The winding start end and the winding end end of the jacket cloth are arranged with a gap without overlapping each other in the belt circumferential direction,
The said high-strength fiber sheet has covered the said gap | interval in the said boundary part in the state which overlapped with the edge part of the said winding start of the said covering cloth, and the edge part of the said winding end, respectively. Wrapped V-belt as described in 1.   The wrapped V-belt according to claim 1 or 2, wherein the high-strength fiber sheet is thinner than the jacket cloth.   4. The wrapped V-belt according to claim 1, wherein the high-strength fiber sheet is made of an aramid fiber. Wrapped V belt according to claim 4, wherein the basis weight of the high-strength fiber sheets are 90~870g / m ^2. The wrapped V-belt according to claim 4 or 5, wherein the tensile strength of the high-strength fiber sheet is 2060 N / mm ² or more.   The wrapped V-belt according to any one of claims 4 to 6, wherein the high-strength fiber sheet has a thickness of 0.03 to 0.24 mm.   The wrapped V-belt according to any one of claims 1 to 3, wherein the high-strength fiber sheet is made of carbon fiber. Wrapped V belt according to claim 8, wherein the basis weight of the high-strength fiber sheets are 200-30Og / m ^2. The wrapped V-belt according to claim 8 or 9, wherein the high-strength fiber sheet has a tensile strength of 2900 N / mm ² or more.   The wrapped V-belt according to any one of claims 8 to 10, wherein the high-strength fiber sheet has a thickness of 0.05 to 0.09 mm.   12. The high-strength fiber sheet is arranged such that two directions where the fiber bundles intersect each other are inclined with respect to a belt circumferential direction and a belt width direction. The wrapped V-belt according to claim 1. The rubber layer is
2. A compression rubber layer, an extension rubber layer, an adhesive rubber layer disposed between the compression rubber layer and the extension rubber layer, and a core wire embedded in the adhesive rubber layer. 13. The wrapped V belt according to any one of 12 above.   The surface of the high-strength fiber sheet on the rubber layer side is subjected to an adhesion treatment for improving the adhesion with the rubber layer. Wrapped V belt. The belt width is 13 to 70 mm,
The wrapped V-belt according to any one of claims 1 to 14, wherein a belt thickness is 5 to 25 mm.

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