JP6902443B2 - Friction transmission belt - Google Patents

Description

The present invention relates to a friction transmission belt having a V-shaped cross section orthogonal to the belt circumferential direction and having friction transmission surfaces on both sides in the belt width direction.

The friction transmission belt, which has a V-shaped cross section and transmits power by friction transmission, is covered with a 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 sheet, and it is used properly according to the application due to the difference in the surface texture (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.

In the friction transmission belt, bending conditions such as a bending angle and the number of bending points are becoming stricter due to an increase in the driven shaft due to a smaller diameter of the pulley and diversification of functions. Therefore, it is required to improve the bending resistance of the friction transmission belt. Conventionally, various methods have been proposed to satisfy this requirement. For example, in order to reduce the bending stress, the thickness of the cross-sectional dimension is reduced, or a plurality of cogs are provided on the inner peripheral side of the belt. Further, in Patent Document 1, in order to prevent cracks on the inner peripheral side of the friction transmission belt, two diagonal blind cords are embedded in the vicinity of the inner peripheral surface of the belt so that the cords intersect. As the material of this diagonal blind cord, 6 nylon is described.

Special Publication No. 59-7859

By the way, for example, in a large agricultural machine or the like, a friction transmission belt having a large cross-sectional area is used. The belt mechanism of a large agricultural machine operates continuously for a long time with high load and high tension. In addition, the belt mechanism of large agricultural machinery often has a multi-axis layout. Therefore, the bending condition of the belt is stricter than that of the belt mechanism of a vehicle or a machine for general industry, and cracks are likely to occur on the inner peripheral side of the belt.

In addition, large agricultural machines are often equipped with a belt tension clutch mechanism. The belt tension clutch mechanism has a tension pulley whose position can be switched, and the tension pulley is brought into contact with the outer peripheral surface of the friction transmission belt to apply tension to transmit power, and the tension pulley is transferred to the friction transmission belt. Power transmission is cut off by not applying tension away from the outer peripheral surface of the belt. At the time of power transmission, the friction transmission belt is in a reverse bending state by the tension pulley. Moreover, in the belt tension clutch mechanism of a large agricultural machine, the contact angle (winding angle) of the belt with respect to the tension pulley is large. Therefore, in the belt tension clutch mechanism of a large agricultural machine, the bending condition of the belt is more severe, and cracks are more likely to occur on the inner peripheral side of the belt.

In addition, the belt mechanisms used for large compressors, crushers, generators, pumps, etc. have similar operating conditions to the belt mechanisms of large agricultural machines, so these belt mechanisms also have strict belt bending conditions and are on the inner circumference side of the belt. Is prone to cracking.

In order to prevent cracking of a large friction transmission belt used under such particularly severe bending conditions, it is conceivable to apply the technique of Patent Document 1. However, the friction transmission belt of Patent Document 1 is a small friction transmission belt used for machines for automobiles and general industries, and is not intended to be used with a high load and a high tension like a large agricultural machine. Therefore, even if the structure of the friction transmission belt of Patent Document 1 is applied to a large friction transmission belt, cracks on the inner peripheral side of the belt cannot be suppressed.

An object of the present invention is to provide a friction transmission belt capable of preventing cracks on the inner peripheral side of the belt even when used under severe bending conditions while suppressing a decrease in flexibility.

Means for Solving Problems and Effects of Invention

The friction transmission belt of the present invention is an annular friction transmission belt having a V-shaped cross section orthogonal to the belt circumferential direction and having friction transmission surfaces on both sides in the belt width direction, and is embedded in a rubber layer and the rubber layer. It has a belt main body including a core wire and a reinforcing sheet embedded in the rubber layer on the inner peripheral side of the belt of the core wire, and the inner peripheral surface of the belt main body is formed of the rubber layer. It is exposed to the outside or covered with a cover sheet, and the maximum length in the belt thickness direction from the center of the core wire to the inner peripheral surface of the belt body is the same from the center of the core wire to the inner peripheral surface of the belt body. The ratio of the maximum length in the belt thickness direction to the reinforcing sheet is 70% or more and 98% or less, and the reinforcing sheet has a structure in which fiber bundles of high-strength fibers are arranged so as to intersect and is woven. It is characterized by being composed of a high-strength fiber sheet having a structure or a knitted structure.

According to this configuration, a reinforcing sheet made of a high-strength fiber sheet is embedded in the vicinity of the inner peripheral surface of the belt body. The high-strength fiber sheet has a structure in which fiber bundles of high-strength fibers are arranged so as to intersect with each other. Therefore, at least a part of the fiber bundles of the high-strength fibers constituting the reinforcing sheet is arranged parallel to the belt circumferential direction or inclined with respect to the belt circumferential direction. Therefore, even if the friction transmission belt is used under severe bending conditions such as the belt mechanism of a large agricultural machine, it is possible to prevent the occurrence of cracks on the inner peripheral surface of the belt body. Further, even if a crack occurs on the inner peripheral surface of the belt body, the reinforcing sheet can prevent the propagation of the crack. Further, since the reinforcing sheet is composed of high-strength fibers, the thickness can be reduced. Therefore, even if the reinforcing sheet is embedded, it is possible to suppress a decrease in the flexibility of the friction transmission belt. As described above, the friction transmission belt of the present invention can prevent cracks on the inner peripheral side of the belt even when used under severe bending conditions while suppressing a decrease in flexibility.

In the friction transmission belt of the present invention, it is preferable that the cover sheet covers the entire circumference of the belt body and is composed of the high-strength fiber sheet.

According to this configuration, the inner peripheral surface of the belt body is covered with a cover sheet made of a high-strength fiber sheet. Therefore, the occurrence of cracks on the inner peripheral surface of the belt body can be prevented more reliably.
Further, when the friction transmission surface of the friction transmission belt is composed of a conventional cover sheet such as cotton, the friction transmission surface is worn, especially when used under high load and high tension conditions such as a large agricultural machine. It's easy to do. However, since the friction transmission surface of the friction transmission belt of the present invention is composed of a cover sheet of a high-strength fiber sheet, wear of the friction transmission surface can be suppressed.

In the friction transmission belt of the present invention, it is preferable that the reinforcing sheet is arranged so that the two intersecting directions of the fiber bundles are inclined with respect to the peripheral direction of the belt.

According to this configuration, the fiber bundles constituting the reinforcing sheet embedded in the belt body are arranged so as to be inclined with respect to the belt circumferential direction, so that a part of the fiber bundles constituting the reinforcing sheet is parallel to the belt circumferential direction. It is possible to increase the flexibility of the friction transmission belt as compared with the case where it is arranged in.

In the friction transmission belt of the present invention, the reinforcing sheet may be arranged so that the two intersecting directions of the fiber bundles are the belt circumferential direction and the belt width direction.

According to this configuration, the fiber bundles constituting the reinforcing sheet embedded in the belt body are arranged along the belt circumferential direction and the belt width direction, so that the fiber bundles constituting the reinforcing sheet are inclined with respect to the belt circumferential direction. It is possible to increase the rigidity of the friction transmission belt in the belt circumferential direction and the belt width direction as compared with the case where the friction transmission belt is arranged.

In the friction transmission belt of the present invention, it is preferable that the cover sheet is arranged so that the two intersecting directions of the fiber bundles are inclined with respect to the peripheral direction of the belt.

According to this configuration, the fiber bundles constituting the cover sheet covering the entire circumference of the belt body are arranged so as to be inclined with respect to the belt circumferential direction, so that a part of the fiber bundles constituting the cover sheet is in the belt circumferential direction. The flexibility of the friction transmission belt can be improved as compared with the case where they are arranged in parallel.

In the friction transmission belt of the present invention, the cover sheet may be arranged so that the two intersecting directions of the fiber bundles are orthogonal to the belt circumferential direction and the belt circumferential direction.

According to this configuration, a part of the fiber bundles constituting the cover sheet covering the entire circumference of the belt body is arranged along the belt circumferential direction, so that the rigidity of the friction transmission belt in the belt circumferential direction can be increased. Further, since a part of the fiber bundles constituting the cover sheet is along the belt width direction on the inner peripheral surface and the outer peripheral surface of the belt body, the rigidity of the friction transmission belt in the belt width direction can be increased. ..

The friction transmission belt of the present invention preferably has a maximum length in the belt width direction of 12 to 70 mm and a belt thickness of 5 to 26 mm.

In the friction transmission belt of the present invention, the high-strength fiber sheet preferably has a tensile strength of 2000 N / mm ² or more in two directions in which the fiber bundles intersect.

In the friction transmission belt of the present invention, the high-strength fiber sheet at least one of the reinforcing sheet and the cover sheet preferably contains at least one of aramid fibers and carbon fibers.

In the friction transmission belt of the present invention, when the high-strength fiber sheet has a structure in which fiber bundles of aramid fibers are arranged intersecting with each other, the grain size is 90 to 870 g / m ² , and the fiber bundles of carbon fibers are formed. In the case of a structure arranged so as to intersect with each other, the amount of grain is preferably ^{200 to 300 g / m 2.}

In the friction transmission belt of the present invention, when the high-strength fiber sheet has a structure in which fiber bundles of aramid fibers are arranged so as to intersect, the thickness is 0.03 to 0.24 mm, and the fiber bundles of carbon fibers are formed. When the structures are arranged so as to intersect with each other, the thickness is preferably 0.05 to 0.09 mm.

In the friction transmission belt of the present invention, it is preferable that at least one of the reinforcing sheet and the cover sheet is subjected to an adhesive treatment for enhancing the adhesiveness with the rubber layer.

According to this configuration, it is possible to prevent the reinforcing sheet or the cover sheet that has been subjected to the adhesive treatment from being peeled off from the rubber layer.

It is sectional drawing of the friction transmission belt which concerns on embodiment of this invention. It is a top view of the high-strength fiber sheet. It is a perspective view explaining the manufacturing procedure of a friction transmission belt. It is sectional drawing in the process of manufacturing a friction transmission belt. It is a perspective view explaining another manufacturing procedure of a friction transmission belt. It is a figure explaining the use example of a friction transmission belt. It is a top view of the high-strength fiber sheet of a modified example. It is sectional drawing of the friction transmission belt which concerns on other embodiment of this invention. It is a schematic diagram of the large power transmission device used in the impact resistance test.

Next, an embodiment of the present invention will be described.
The friction transmission belt 1 of the present embodiment is used, for example, in a transmission mechanism of a large agricultural machine, a large compressor, a crusher, a generator, a pump, and the like. However, the friction transmission belt of the present invention can be applied to industrial machines and vehicles other than the above. As shown in FIG. 1, the friction transmission belt 1 is used by being wound around a pulley 100 having a V-shaped groove 101 (hereinafter, referred to as a V groove 101).

The friction transmission belt 1 is annular and is used by being wound around at least two pulleys 100 (drive pulley and driven pulley). In the following description, the belt circumferential direction, the belt width direction, the belt thickness direction, the belt outer peripheral side, and the belt inner peripheral side are the directions shown in FIG. The friction transmission belt 1 has a V-shaped cross section orthogonal to the belt circumferential direction, and is sandwiched between V grooves 101 of the pulley 100 for use. The friction transmission belt 1 has friction transmission surfaces 1a and 1b on both sides in the belt width direction. The friction transmission surfaces 1a and 1b come into contact with the V groove 101 of the pulley 100. Power is transmitted between the friction transmission belt 1 and the pulley 100 by the frictional force due to this contact. The maximum length of the friction transmission belt 1 in the belt width direction is, for example, 12 to 70 mm. Considering the effect described later of the friction transmission belt 1, 20 to 70 mm is more effective, and 30 to 70 mm is further effective. The belt thickness of the friction transmission belt 1 is, for example, 5 to 26 mm. Considering the effect described later of the friction transmission belt 1, 11 to 26 mm is more effective, and 18 to 26 mm is further effective.

The friction transmission belt 1 is a wrapped V-belt, and has a belt main body 2 and a cover sheet 3 that covers the entire circumference of the belt main body 2. The belt body 2 has a rubber layer 4, a core wire 5 embedded in the rubber layer 4, and a reinforcing sheet 6 embedded in the rubber layer 4. The inner peripheral surface and the outer peripheral surface of the belt body 2 are formed of the rubber layer 4.

The rubber layer 4 has an adhesive rubber layer 7 in which a core wire 5 is embedded, a compressed rubber layer 8 in which a reinforcing sheet 6 is embedded, and an stretch rubber layer 9. The compression rubber layer 8 is provided on the inner peripheral side of the belt of the adhesive rubber layer 7. When the compressed rubber layer 8 is wound around the pulley 100 and traveled, the compressed rubber layer 8 is compressed in the circumferential direction of the belt. The stretch rubber layer 9 is provided on the outer peripheral side of the belt of the adhesive rubber layer 7. The stretch rubber layer 9 is stretched in the circumferential direction of the belt when it is wound around the pulley 100 and traveled. The thickness of the compressed rubber layer 8 is larger than the thickness of the stretched rubber layer 9. In FIG. 1, the entire core wire 5 is embedded in the adhesive rubber layer 7, but only a part of the core wire 5 (for example, the portion on the inner peripheral side of the belt) may be embedded in the adhesive rubber layer 7. The reinforcing sheet 6 is embedded on the inner peripheral side of the belt of the core wire 5. That is, the reinforcing sheet 6 is embedded in the compressed rubber layer 8. The reinforcing sheet 6 is embedded in the vicinity of the inner peripheral surface of the belt main body 2. Let L1 be the maximum length in the belt thickness direction from the center of the core wire 5 to the inner peripheral surface of the belt body 2. Let L2 be the maximum length in the belt thickness direction from the center of the core wire 5 to the reinforcing sheet 6. The ratio of the length L2 to the length L1 is 70% or more and 98% or less.

The adhesive rubber layer 7, the compressed rubber layer 8, and the stretched 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 adhesiveness to the core wire 5 and the reinforcing sheet 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, vulcanized or crosslinkable rubber is used. Specifically, for example, diene rubber (natural rubber, isoprene rubber, butadiene rubber, chloroprene rubber, styrene butadiene rubber, acrylonitrile butadiene rubber, hydride nitrile rubber, etc.), ethylene-α-olefin elastomer, chlorosulphonized polyethylene rubber, etc. , Alkylated chlorosulphonized 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.

Vulcanization agents or cross-linking agents, co-cross-linking agents, vulcanization aids, vulcanization accelerators, vulcanization retarders, metal oxides (zinc oxide, magnesium oxide, calcium oxide, etc.) may be added to the rubber composition, if necessary. Barium oxide, iron oxide, copper oxide, titanium oxide, aluminum oxide, etc.), enhancer (carbon black, silicon oxide such as hydrous silica, etc.), short fibers, filler (clay, calcium carbonate, talc, mica, etc.), softening Agents (oils such as paraffin oils and naphthenic oils), processing agents or processing aids (stearic acid, metal stearate, wax, paraffin, etc.), antioxidants (antioxidants, heat antiaging agents, bending Crack inhibitor, ozone deterioration inhibitor, etc.), colorant, tackifier, plasticizer, coupling agent (silane coupling agent, etc.), stabilizer (ultraviolet absorber, heat stabilizer, etc.), flame retardant, antistatic Agents and the like may be blended. The metal oxide may be blended as a cross-linking 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 5 extends in the circumferential direction of the belt and is embedded at regular intervals in the width direction of the belt. The core wire 5 is composed of a twisted cord (various twists, single twists, rank twists, etc.) using a multifilament yarn. The material of the core wire 5 is, for example, a synthetic fiber such as an aramid fiber or an inorganic fiber such as a carbon fiber. The core wire 5 may be subjected to an adhesive treatment with an RFL liquid or the like for the purpose of enhancing the adhesiveness with the adhesive rubber layer 7.

As shown in FIG. 2, the reinforcing sheet 6 and the cover sheet 3 are made of the same high-strength fiber sheet 10. The high-strength fiber sheet 10 is woven with a plurality of first fiber bundles 10a and a plurality of second fiber bundles 10b orthogonal to the first fiber bundle 10a.

The first fiber bundle 10a and the second fiber bundle 10b of the reinforcing sheet 6 are inclined with respect to the belt circumferential direction. Further, the first fiber bundle 10a and the second fiber bundle 10b of the cover sheet 3 are also inclined with respect to the belt circumferential direction. For example, the first fiber bundle 10a is inclined by 45 ° with respect to the belt circumferential direction.

The first fiber bundle 10a and the second fiber bundle 10b of the reinforcing sheet 6 may be along the belt circumferential direction and the belt width direction, respectively. Further, the first fiber bundle 10a and the second fiber bundle 10b of the cover sheet 3 may be along the belt circumferential direction and the direction orthogonal to the belt circumferential direction, respectively. In these cases, the direction of the first fiber bundle 10a does not have to be exactly parallel to the belt circumferential direction. The first fiber bundle 10a may be tilted by about 2 ° with respect to the belt circumferential direction. Further, the second fiber bundle 10b may be inclined by about 2 ° with respect to the belt width direction. In the present invention, the two directions of the fiber bundle, the belt circumferential direction and the belt width direction, include the case where the fiber bundle is inclined by about 2 ° with respect to the belt circumferential direction and the belt width direction, respectively.

The fiber bundles 10a and 10b are composed of high-strength fibers such as aramid fibers and carbon fibers. The fibers constituting the first fiber bundle 10a and the second fiber bundle 10b may be the same or different. Each fiber bundle has a structure in which a plurality of filaments (long fibers) are aligned. The tensile strength in the orientation direction of the first fiber bundle 10a and the orientation direction of the second fiber bundle 10b is preferably ^{2000 N / mm 2 or more, for example.} When both the first fiber bundle 10a and the second fiber bundle 10b are composed of aramid fibers, for example, it is 2060 N / mm ² or more, and both the first fiber bundle 10a and the second fiber bundle 10b are composed of carbon fibers. In this case, for example, it is 2900 N / mm ² or more. The amount of the high-strength fiber sheet 10 is, for example, 90 to 870 g / m ² when both the first fiber bundle 10a and the second fiber bundle 10b are composed of aramid fibers, and the first fiber bundle 10a and the second fiber bundle 10a and the second fiber bundle 10a. When both of the fiber bundles 10b are composed of carbon fibers, it is, for example, 200 to 300 g / m ² . The thickness of the high-strength fiber sheet 10 is, for example, 0.03 to 0.24 mm when both the first fiber bundle 10a and the second fiber bundle 10b are composed of aramid fibers, and the first fiber bundle 10a and the first fiber bundle 10a have a thickness of 0.03 to 0.24 mm. When both of the two fiber bundles 10b are composed of carbon fibers, it is, for example, 0.05 to 0.09 mm.

The high-strength fiber sheet 10 constituting the reinforcing sheet 6 may be subjected to an adhesive treatment for enhancing the adhesiveness with the rubber layer 4 (compressed rubber layer 8). The high-strength fiber sheet 10 constituting the cover sheet 3 may be subjected to an adhesive treatment for enhancing the adhesiveness with the rubber layer 4.
The adhesive treatment may be an RFL treatment in which the fibers constituting the high-strength fiber sheet 10 or the high-strength fiber sheet 10 are immersed in an RFL liquid, or an impregnated resin treatment in which the fibers are immersed in a resin solution. The RFL solution is a mixture of an initial condensate of resorcin and formalin into latex, and the latex used here includes styrene-butadiene-pyridine ternary copolymer, hydrogenated nitrile rubber, chlorosulfonated polyethylene, and epichlorohydrin. Such as latex. The resin solution used for the impregnating resin treatment is, for example, an isocyanate solution or an epoxy solution. After the impregnated resin treatment, an adhesion treatment using an RFL liquid treatment may be performed.
Further, as an adhesive 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 10, and then the solvent is evaporated to the surface of the high-strength fiber sheet 10. A rubber glue treatment for forming a film of the unvulcanized rubber composition may be performed. The rubber glue treatment may be performed after the RFL treatment or the impregnated resin treatment.
Further, as the bonding treatment, a friction treatment may be performed. In the friction treatment, a calendar roll is used, and the unvulcanized rubber composition and the cover sheet 3 are simultaneously passed between the rolls rotating at different surface speeds, so that the unvulcanized rubber composition is passed between the fibers of the cover sheet 3 at the same time. This is a process of rubbing the rubber composition.

Next, the manufacturing procedure of the friction transmission belt 1 will be described with reference to FIGS. 3 and 4.
First, as shown in FIG. 3, the unvulcanized rubber sheet 118A forming a part of the compressed rubber layer 8 is wound around the cylindrical molding drum M. Next, a long strip 116 of the high-strength fiber sheet 10 is prepared. The strip 116 serves as a reinforcing sheet 6. The strip 116 may be subjected to an adhesive treatment such as an RFL treatment, an impregnated resin treatment, or a rubber glue treatment in order to enhance the adhesive strength with the surrounding rubber layer. The width of the strip 116 is smaller than the total width of the sleeve (cylindrical body) formed of the unvulcanized rubber sheet 118A. The width of the strip 116 may be larger or smaller than the belt width of the friction transmission belt 1. The strip 116 is spirally wound at the same pitch as the width of the strip 116. That is, the adjacent strips 116 are wound so as not to overlap. When the direction of the first fiber bundle 10a of the strip 116 coincides with the longitudinal direction of the strip 116, the direction of the first fiber bundle 10a of the reinforcing sheet 6 is substantially parallel to the belt circumferential direction. When the direction of the first fiber bundle 10a of the strip 116 is inclined with respect to the longitudinal direction of the strip 116, the direction of the first fiber bundle 10a of the reinforcing sheet 6 is the direction inclined with respect to the belt circumferential direction. ..

Subsequently, the unvulcanized rubber sheet 118B (see FIG. 4) constituting the remaining portion of the compressed rubber layer 8 is wound, and then the unvulcanized rubber sheet 117A (see FIG. 4) constituting a part of the adhesive rubber layer 7 is wound. ) Wrap. After that, one core wire 5 is spirally wound. Alternatively, a plurality of core wires 5 are wound at predetermined intervals. Next, the unvulcanized rubber sheet 117B (see FIG. 4) constituting the remaining portion of the adhesive rubber layer 7 is wound, and then the unvulcanized rubber sheet 119 (see FIG. 4) constituting the stretched rubber layer 9 is wound. To form an unvulcanized belt sleeve.

Next, the unvulcanized belt sleeve is cut to a predetermined width and cut so that the cross section has a V shape, and the belt body 2 in the unvulcanized state is processed. After that, the belt body 2 is covered with the cover sheet 3 which has been subjected to an adhesive treatment such as friction treatment to form an unvulcanized belt. Then, the unvulcanized belt is fitted into a molding die and heated and pressed to vulcanize (or crosslink) the unvulcanized rubber. As a result, the friction transmission belt 1 is formed.

In the above manufacturing procedure, the components on the inner peripheral side of the friction transmission belt 1 are wound around the molding drum M in order, but the components on the outer peripheral side of the friction transmission belt 1 may be wound around the molding drum M in order. ..

Further, in the above manufacturing procedure, the strip-shaped body 116 constituting the reinforcing sheet 6 is spirally wound, but as shown in FIG. 5, the width is the same as the total width of the sleeve formed of the unvulcanized rubber sheet 119. The reinforcing sheet 6 to be held may be wound around.

According to the friction transmission belt 1 of the present embodiment, the following effects can be obtained.
A reinforcing sheet 6 made of a high-strength fiber sheet 10 is embedded in the vicinity of the inner peripheral surface of the belt body 2. The high-strength fiber sheet 10 has a structure in which fiber bundles 10a and 10b of high-strength fibers are arranged so as to intersect with each other. Therefore, at least a part of the fiber bundles 10a and 10b constituting the reinforcing sheet 6 is arranged parallel to the belt circumferential direction or inclined with respect to the belt circumferential direction. Therefore, even if the friction transmission belt 1 is used under severe bending conditions such as the belt mechanism of a large agricultural machine, it is possible to prevent the occurrence of cracks on the inner peripheral surface of the belt body 2. Further, even if a crack occurs on the inner peripheral surface of the belt body 2, the reinforcing sheet 6 can prevent the propagation of the crack. Further, since the reinforcing sheet 6 is made of high-strength fibers, the thickness can be reduced. Therefore, even if the reinforcing sheet 6 is embedded, it is possible to suppress a decrease in the flexibility of the friction transmission belt 1. As described above, the friction transmission belt 1 can prevent cracks on the inner peripheral side of the belt even when used under severe bending conditions while suppressing a decrease in flexibility.

Further, the inner peripheral surface of the belt body 2 is covered with a cover sheet 3 made of a high-strength fiber sheet 10. Therefore, the occurrence of cracks on the inner peripheral surface of the belt body 2 can be prevented more reliably.

As described above, at least a part of the fiber bundles 10a and 10b constituting the reinforcing sheet 6 is arranged parallel to the belt circumferential direction or inclined with respect to the belt circumferential direction. Therefore, the rigidity of the friction transmission belt 1 in the belt circumferential direction can be increased.

FIG. 6A is a schematic view of the belt tension clutch mechanism. The belt tension clutch mechanism has a tension pulley 103 that can move over a position where tension is applied to the friction transmission belt 1 and a position where tension is not applied. When the tension pulley 103 applies tension to the friction transmission belt, the friction transmission belt 1 transmits power, and when the tension pulley 103 does not apply tension to the friction transmission belt 1, the friction transmission belt 1 transmits power. do not. At the time of power transmission, the friction transmission belt 1 is in a reverse bending state. In the belt tension clutch mechanism of a large agricultural machine, the contact angle (winding angle) θ of the belt with respect to the tension pulley 103 is large, and bending fatigue tends to be large. Further, the position of the tension pulley 103 is switched in a state where the drive pulley is rotated. Therefore, when tension is applied by the tension pulley 103, the friction transmission belt 1 receives a strong impact. If a conventional friction transmission belt having low rigidity in the belt circumferential direction is used for the belt tension clutch mechanism, the friction transmission belt may break at an early stage. On the other hand, since the friction transmission belt 1 of the present embodiment has high rigidity in the belt circumferential direction, the impact force can be dispersed even if a strong impact is received, and the durability can be improved.

Further, at least a part of the fiber bundles 10a and 10b constituting the reinforcing sheet 6 is parallel to the belt width direction or inclined with respect to the belt width direction on the inner peripheral surface and the outer peripheral surface of the belt body 2. Be placed. Therefore, the rigidity of the friction transmission belt 1 in the belt width direction can be increased.

By increasing the rigidity (side pressure resistance) in the belt width direction, it is possible to prevent the friction transmission belt 1 from buckling and deforming so as to fall into the V groove 101 even when used under a high load or high tension. When buckling deformation occurs, shear stress is generated inside the belt. In particular, shear stress tends to concentrate on interfaces with different mechanical properties, causing interfacial delamination. In the present embodiment, by preventing buckling deformation, interfacial peeling due to shear stress can be suppressed.

When the friction transmission surface of the friction transmission belt is made of a conventional cover cloth such as cotton, the friction transmission surface is likely to be worn when used under high load and high tension conditions such as in a large agricultural machine. In particular, when the friction transmission belt is buckled and deformed so as to fall into the V-groove, a part of the friction transmission surface is locally and greatly worn. Further, for example, as shown in FIG. 6B, when the distance between the pulleys 100 is long, the runout of the friction transmission belt 1 tends to increase when the belt travels. The greater the runout, the more likely the friction transmission surface will wear.
However, since the friction transmission surfaces 1a and 1b of the friction transmission belt 1 of the present embodiment are composed of the cover sheet 3 of the high-strength fiber sheet 10, even if the vibration of the belt is large, the friction transmission surfaces 1a and 1b Abrasion can be suppressed. Further, as described above, buckling deformation can be prevented by increasing the rigidity in the belt width direction, so that local wear of the friction transmission surfaces 1a and 1b can be prevented.

The entire circumference of the belt body 2 is covered with a cover sheet 3 made of a high-strength fiber sheet 10. At least a part of the fiber bundles 10a and 10b of the high-strength fibers constituting the cover sheet 3 is arranged parallel to the belt circumferential direction or inclined with respect to the belt circumferential direction. Therefore, the rigidity of the friction transmission belt 1 in the belt circumferential direction can be increased.
Further, the fiber bundles 10a and 10b constituting the cover sheet 3 are arranged on the inner peripheral surface and the outer peripheral surface of the belt main body 2 in parallel with the belt width direction or inclined with respect to the belt width direction. Therefore, the rigidity of the friction transmission belt 1 in the belt width direction can be increased.

When the fiber bundles 10a and 10b constituting the reinforcing sheet 6 embedded in the belt body 2 are arranged so as to be inclined with respect to the belt circumferential direction, a part of the fiber bundles constituting the reinforcing sheet 6 is aligned with the belt circumferential direction. The flexibility of the friction transmission belt 1 can be improved as compared with the case where the belts are arranged in parallel.

On the other hand, when the fiber bundles 10a and 10b constituting the reinforcing sheet 6 embedded in the belt body 2 are arranged along the belt circumferential direction and the belt width direction, the fiber bundles constituting the reinforcing sheet 6 are arranged in the belt circumferential direction. On the other hand, the rigidity of the friction transmission belt 1 in the belt circumferential direction and the belt width direction can be further increased as compared with the case where the friction transmission belt 1 is arranged at an inclination.

When the fiber bundles 10a and 10b constituting the cover sheet 3 covering the entire circumference of the belt body 2 are arranged so as to be inclined with respect to the belt circumferential direction, a part of the fiber bundles constituting the cover sheet 3 is in the belt circumferential direction. The flexibility of the friction transmission belt 1 can be improved as compared with the case where the belt is arranged in parallel with the above.

On the other hand, when the fiber bundles 10a and 10b constituting the cover sheet 3 covering the entire circumference of the belt main body 2 are arranged along the belt circumferential direction and the direction orthogonal to the belt circumferential direction, the cover sheet 3 is configured. The rigidity of the friction transmission belt 1 in the belt circumferential direction and the belt width direction can be further increased as compared with the case where the fiber bundles are arranged so as to be inclined with respect to the belt circumferential direction.

The reinforcing sheet 6 and the cover sheet 3 are subjected to an adhesive treatment that enhances the adhesiveness with the rubber layer 4.
Therefore, peeling of the reinforcing sheet 6 and the cover sheet 3 from the rubber layer 4 can be prevented.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made as long as they are described in the claims.

In the above embodiment, the reinforcing sheet 6 and the cover sheet 3 are made of the same high-strength fiber sheet 10. However, the material of the high-strength fiber sheet 10 constituting the reinforcing sheet 6 may be different from the material of the high-strength fiber sheet 10 constituting the cover sheet 3. Further, the structure of the high-strength fiber sheet 10 constituting the reinforcing sheet 6 may be different from the structure of the high-strength fiber sheet 10 constituting the cover sheet 3.

In the above embodiment, the reinforcing sheet 6 and the cover sheet 3 are each arranged in only one layer, but may be arranged in two or more layers. When two or more layers of the reinforcing sheets 6 are stacked, the condition that the ratio of the length L2 to the length L1 is 70% or more and 98% or less is satisfied for each reinforcing sheet 6. When two or more layers of the reinforcing sheets 6 are stacked, a rubber layer may be interposed between the reinforcing sheets 6. When manufacturing a friction transmission belt in which two or more layers of reinforcing sheets 6 are laminated using the band-shaped body 116 (see FIG. 3), the band-shaped body 116 is spirally wound at a pitch of the width of the band-shaped body 116, and then on the belt-shaped body 116. Another strip 116 is spirally wound at a pitch of the width of the strip 116. At this time, the ends of the strip 116 are prevented from overlapping. Thereby, the misalignment of the band-shaped body 116 can be prevented.

The high-strength fiber sheet 10 of the above embodiment is woven with fiber bundles arranged so as to be orthogonal to each other, but the high-strength fiber sheet of the present invention is woven with fiber bundles intersecting at angles other than right angles. May be good.

The high-strength fiber sheet of the present invention may be knitted by fiber bundles of high-strength fibers so that the fiber bundles of high-strength fibers intersect. The angle at which the fiber bundles intersect may or may not be a right angle.

In the high-strength fiber sheet of the present invention, for example, as in the high-strength fiber sheet 210 shown in FIG. 7A, the fiber bundles 210a and 210b of the high-strength fibers are arranged so as to intersect (orthogonally in FIG. 7A). The fibers may be woven by the fiber bundles 210a and 210b and the auxiliary threads 206c and 206d so as to have the structure.
The plurality of first fiber bundles 210a are arranged as a whole on the back surface of the plurality of second fiber bundles 210b in the drawing. The first auxiliary thread 210c is arranged between the first fiber bundles 210a in parallel with the first fiber bundle 210a. The second auxiliary thread 210d is arranged between the second fiber bundles 210b in parallel with the second fiber bundle 210b. The first auxiliary thread 210c and the second auxiliary thread 210d hold the first fiber bundle 210a and the second fiber bundle 210b in an intersecting state. The auxiliary threads 210c and 210d are, for example, multifilament threads. The auxiliary yarn is made of high-strength fibers. The first auxiliary thread 210c and the second auxiliary thread 210d may be formed of the same fiber or may be formed of different fibers. The auxiliary threads 210c and 210d may be formed of the same fibers as at least one of the first fiber bundle 210a and the second fiber bundle 210b, or may be formed of fibers different from those of the fiber bundles 210a and 210b.

In the high-strength fiber sheet of the present invention, for example, as in the high-strength fiber sheet 310 shown in FIG. 7 (b), the fiber bundles 310a and 310b of the high-strength fibers are arranged so as to intersect (orthogonally in FIG. 7 (b)). It may have a structure and a knitting structure.
The plurality of first fiber bundles 310a are arranged as a whole on the back surface of the plurality of second fiber bundles 310b in the drawing. The high-strength fiber sheet 310 has a first auxiliary thread 310c and a second auxiliary thread 310d. The first auxiliary yarn 310c and the second auxiliary yarn 310d are knitted through between the first fiber bundle 310a and the second fiber bundle 310b. The first auxiliary thread 310c and the second auxiliary thread 310d hold the first fiber bundle 310a and the second fiber bundle 310b in an intersecting state. The auxiliary threads 310c and 310d are, for example, multifilament threads. The auxiliary threads 310c and 310d are made of high-strength fibers. The first auxiliary thread 310c and the second auxiliary thread 310d may be formed of the same fiber or may be formed of different fibers. The auxiliary threads 310c and 310d may be formed of the same fibers as at least one of the first fiber bundle 310a and the second fiber bundle 310b, or may be formed of fibers different from those of the fiber bundles 310a and 310b.

The friction transmission belt of the present invention may be a low-edge V-belt in which both side surfaces of the belt body in the belt width direction are not covered with a cover sheet. In this case, the cover sheet may not be provided at all, and at least one of the outer peripheral surface and the inner peripheral surface of the belt body may be covered with the cover sheet. The cover sheet that covers the inner peripheral surface of the belt body may or may not be a high-strength fiber sheet. The cover sheet that covers the outer peripheral surface of the belt body may or may not be a high-strength fiber sheet.

The friction transmission belt of the present invention may be a cog belt having a plurality of cogs arranged in the belt circumferential direction on at least one of the inner peripheral surface of the belt and the outer peripheral surface of the belt. An example thereof is shown in FIG. The cog belt 401 shown in FIG. 8 is composed of only the belt main body 402 and does not have a cover sheet for covering the belt main body 402. The inner peripheral surface of the belt body 402 has a plurality of cogs 402a and is uneven. The belt main body 402 has a reinforcing sheet 406 embedded in the compressed rubber layer 408 along the unevenness of the inner peripheral surface of the belt main body 402. The reinforcing sheet 406 is composed of a high-strength fiber sheet 10. The ratio of the maximum length L42 from the center of the core wire 5 to the reinforcing sheet 6 with respect to the maximum length L41 from the center of the core wire 5 to the inner peripheral surface of the belt body 2 is 70% or more and 98% as in the above embodiment. It is as follows. For molding the cog 402a, the unvulcanized belt sleeve or the unvulcanized belt body 402 is fitted into a molding base mold (mold or rubber mold) having irregularities formed in the same manner as a general cog belt. Do it with. At least one of the inner peripheral surface and the outer peripheral surface of the belt body of the cog belt may be covered with a cover sheet. This cover sheet may or may not be a high-strength fiber sheet.

When the high-strength fiber sheet 10 forming the reinforcing sheet 6 is subjected to an adhesive treatment such as RFL treatment, impregnation resin treatment, and rubber glue treatment, the rubber sheet 118A is provided if the above-mentioned conditions of length L1 and length L2 are satisfied. (See FIG. 4) does not have to be wound around the molding drum M.

In the above embodiment, both sides of the reinforcing sheet 6 in the belt thickness direction are formed of the same rubber composition, but may be formed of different rubber compositions. That is, the compositions of the rubber sheet 118A and the rubber sheet 118B in FIG. 4 may be different.

In the above embodiment, the rubber layer 4 has the adhesive rubber layer 7 between the compressed rubber layer 8 and the stretched rubber layer 9, but the adhesive rubber layer 7 may not be provided. In this case, the rubber layer 4 is preferably composed of the compressed rubber layer 8 and the stretched rubber layer 9 composed of a rubber composition different from the rubber composition of the compressed rubber layer 8. The core wire 5 may be embedded in the compression rubber layer 8, may be embedded in the stretch rubber layer 9, or may be buried between the compression rubber layer 8 and the stretch rubber layer 9. Further, the rubber layer 4 may be composed of one kind of rubber composition.

Next, specific examples of the present invention will be described.

As the unvulcanized rubber sheets forming the rubber layer of the belt body of the friction transmission belts of Examples 1 to 8 and Comparative Examples 1 to 3, the unvulcanized rubber sheets of the rubber compositions 1 to 3 shown in Table 1 below were prepared. did.

Details of the formulations in Table 1 are as follows.
-Chloroprene rubber: "PM-40" manufactured by DENKA Co., Ltd.
-Magnesium oxide: "Kyowa Mag 30" manufactured by Kyowa Chemical Industry Co., Ltd.
・ Stearic acid: "Stearic acid camellia" manufactured by NOF CORPORATION
・ Anti-aging agent: "Non-flex OD-3" manufactured by Seiko Chemical Co., Ltd.
-Carbon black: "Seast 3" manufactured by Tokai Carbon Co., Ltd.
-Plasticizer: "RS-700" manufactured by ADEKA Corporation
-Vulcanization accelerator: "Noxeller TT" manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.
-Zinc oxide: "Zinc oxide 3 types" manufactured by Shodo Chemical Industry Co., Ltd.

Using the unvulcanized rubber sheets of the rubber compositions 1 to 3, the friction transmission of Examples 1 to 8 and Comparative Examples 1 to 3 having the configurations shown in Table 2 was carried out in the same procedure as the friction transmission belt 1 of the above embodiment. I made a belt. The friction transmission belts of Examples 1 to 8 and Comparative Examples 1 to 3 are V-belts having a circumference of 120 inches and a belt type of C type. Note that L2 / L1 in Table 2 is the belt thickness direction from the center of the core wire to the reinforcing sheet with respect to the maximum length (L1) in the belt thickness direction from the center of the core wire to the inner peripheral surface of the belt body. The ratio of the maximum length (L2) of is shown.

Table 3 shows the configurations of the aramid sheets 1 to 3 and the carbon sheets 1 and 2 used as the cover sheet and the reinforcing sheet of Examples 1 to 8 and Comparative Example 1. Both the aramid sheets 1 to 3 and the carbon sheets 1 and 2 are knitted so that fiber bundles of high-strength fibers intersect. The cover sheet and the reinforcing sheet composed of the aramid sheets 1 to 3 and the carbon sheets 1 and 2 were subjected to friction treatment using the unvulcanized rubber composition 3.

The cotton cloth used as the cover sheet of Example 8 and Comparative Examples 2 and 3 and the reinforcing sheet of Comparative Example 2 is a plain weave woven cloth woven with a 20-count cotton warp and a 20-count cotton weft. The yarn densities of the warp and weft were 75 threads / 50 mm, respectively, and the basis weight of the woven fabric was 280 g / m ² . The cover sheet or reinforcing sheet made of cotton cloth was subjected to friction treatment using the unvulcanized rubber composition 3.

For the core wires of the friction transmission belts of Examples 1 to 8 and Comparative Examples 1 to 3, a twisted cord of polyester fibers having an average wire diameter of 1.985 mm was used.

[Impact resistance test]
The friction transmission belts of Examples 1 to 8 and Comparative Examples 1 to 3 were subjected to an impact resistance test using the large power transmission device shown in FIG. The large power transmission device includes a drive pulley Dr with an outer diameter of 245 mm, a driven pulley Dn with an outer diameter of 330 mm, and a tension pulley Tn with an outer diameter of 80 mm. The drive pulley Dr and the driven pulley Dn are V pulleys having a V groove. The tension pulley Tn is movable over a position where it does not contact the belt and a position where it contacts the belt and applies tension. When the tension pulley Tn is in a position where it does not contact the belt (a position where tension is not applied to the belt), power is not transmitted from the drive pulley Dr to the driven pulley Dn. While alternately switching the position of the tension pulley Tn between the position where tension is applied to the belt (40 seconds) and the position where tension is not applied (20 seconds), the drive pulley Dr is rotated at a rotation speed of 1800 rpm to run the belt. .. The load of the tension pulley Tn when the tension pulley Tn applies tension to the belt was 17 kg, and the load of the drive pulley Dr was 15 ps.

The friction transmission belt was run for 72 hours while confirming that there were no cracks on the inner peripheral side of the friction transmission belt. The contact angle θ of the belt with respect to the tension pulley Tn at the position where tension is applied to the belt after the running is stopped (see FIG. 9), the shortest distance D of the inner peripheral surface of the belt (see FIG. 9), the rideout RO, and the belt. The temperature of each side surface was measured, and it was visually confirmed whether or not a crack had occurred on the inner peripheral side of the belt. The results are shown in Table 4. The rideout RO is the length in the belt thickness direction from the outer peripheral surface of the belt 10 to the outer peripheral surface of the drive pulley Dr. Before traveling, the contact angle θ of the friction transmission belt with respect to the tension pulley Tn at the position where the tension pulley Tn applies tension to the belt is 135 °, the shortest distance D of the inner peripheral surface of the belt is 142 mm, and the rideout. The RO was 2.4 mm.

As shown in Table 4, in Examples 1 to 8 in which the reinforcing sheet of the high-strength fiber was used and the L2 / L1 was 70 to 98%, no crack was generated after running for 72 hours. From the results of Examples 1 to 3, it can be seen that there is no difference in crack resistance even if L2 / L1 is changed within the range of 70 to 98%. From the results of Examples 4 to 8, it can be seen that there is no difference in crack resistance even if the types of high-strength fibers constituting the reinforcing sheet are changed under the same conditions of L2 / L1.

In Comparative Example 1 in which the material is the same as in Examples 1 to 3 and L2 / L1 is less than 70%, the contact angle θ of the belt with respect to the tension pulley Tn, the shortest distance D of the inner peripheral surface of the belt, and the ride-out RO before and after running. Although no major changes were seen, cracks occurred on the inner circumference of the belt. Further, the belt side surface temperature of Comparative Example 1 after traveling for 72 hours was higher than that of Examples 1 to 3. From this result, in Comparative Example 1, since the reinforcing sheet was closer to the axis of the tension pulley Tn than in Examples 1 to 3, the stress at the time of reverse bending by the tension pulley Tn became higher, and as a result, self-heating was generated. Is thought to have increased. Then, it is considered that the increase in the belt temperature promotes the curing due to the thermal deterioration of the rubber, and the cracks caused by the curing of the rubber are generated.

In Comparative Examples 2 and 3 having the same configuration as in Example 8 except that the reinforcing sheet of high-strength fiber was not used, cracks were generated on the inner peripheral side of the belt at an early stage. In Comparative Example 2 using the reinforcing sheet of cotton cloth, the contact angle θ of the belt with respect to the tension pulley Tn and the change of the ride-out RO before and after running were larger than those of Example 8. Further, in Comparative Example 3 without the reinforcing sheet, the changes in the contact angle θ of the belt with respect to the tension pulley Tn, the shortest distance D of the inner peripheral surface of the belt, and the ride-out RO before and after running were further larger than those in Comparative Example 2. From this result, in Example 8, by using the reinforcing sheet of high-strength fiber, the belt does not fall into the V-groove of the pulley, the contact angle θ of the belt with respect to the tension pulley Tn, and the ride-out RO. It is probable that the change could be suppressed. By suppressing the belt from falling into the V-groove, it is possible to prevent the belt winding diameter from becoming smaller. As a result, the flexibility of the reinforcing sheet can be maintained. In addition, bending fatigue of the belt can be reduced. Furthermore, self-heating due to bending can be suppressed. In Example 8, it is considered that the occurrence of cracks due to the hardening of the rubber could be suppressed by suppressing the self-heating due to bending.
Further, in Example 8, since the belt is suppressed from falling into the V-groove as compared with Comparative Examples 2 and 3, it can be inferred that wear due to the pulleys (drive pulley Dr and driven pulley Dn) on the side surface of the belt can be suppressed. .. Therefore, it is presumed that not only the crack resistance but also the wear resistance can be improved by using the reinforcing sheet of high-strength fiber.

In Examples 1 to 7 using the high-strength fiber cover sheet, the contact angle θ of the belt with respect to the tension pulley Tn and the shortest distance D of the inner peripheral surface of the belt are compared with Example 8 in which the high-strength fiber cover sheet is not used. , And the change in ride-out RO before and after running was small. Further, the belt side surface temperature after running for 72 hours in Examples 1 to 7 was suppressed to be lower than that in Example 8. In Examples 1 to 7, by using the cover sheet of high-strength fiber, the belt does not fall into the V-groove of the pulley, the contact angle θ of the belt with respect to the tension pulley Tn, and the shortest distance between the inner peripheral surfaces of the belt. It is considered that the changes in D and rideout RO could be suppressed. By suppressing the belt from falling into the V-groove, it is possible to prevent the belt winding diameter from becoming smaller. As a result, the flexibility of the reinforcing sheet can be maintained. In addition, bending fatigue of the belt can be reduced. Furthermore, self-heating due to bending can be suppressed. It is considered that Examples 1 to 7 were able to suppress self-heating due to bending as compared with Example 8. Therefore, it can be seen that it is preferable to use a high-strength fiber as the cover sheet as in Examples 1 to 7 in order to suppress curing due to thermal deterioration of the rubber and further improve the crack resistance.
Further, in Examples 1 to 7, since the belt is suppressed from falling into the V groove as compared with Example 8, it can be inferred that wear due to the pulleys (drive pulley Dr and driven pulley Dn) on the side surface of the belt can be suppressed. .. Therefore, it is presumed that not only crack resistance but also wear resistance can be improved by using a cover sheet made of high-strength fiber.

1,401 Friction transmission belt 1a, 1b Friction transmission surface 2,402 Belt body 3 Cover sheet 4 Rubber layer 5 Core wire 6,406 Reinforcing sheet 10, 210, 310 High-strength fiber sheet 10a, 210a, 310a First fiber bundle 10b , 210b, 310b 2nd fiber bundle L1, L41 Maximum length in the belt thickness direction from the center of the core wire to the inner peripheral surface of the belt body L2, L42 Maximum length in the belt thickness direction from the center of the core wire to the reinforcing sheet

Claims (9)

An annular friction transmission belt having a V-shaped cross section orthogonal to the belt circumferential direction and friction transmission surfaces on both sides in the belt width direction.
With a rubber layer
The core wire embedded in the rubber layer and
A belt body including a reinforcing sheet embedded in the rubber layer on the inner peripheral side of the belt of the core wire is provided.
The inner peripheral surface of the belt body is formed of the rubber layer and is exposed to the outside or covered with a cover sheet.
The ratio of the maximum length in the belt thickness direction from the center of the core wire to the reinforcing sheet is 70% of the maximum length in the belt thickness direction from the center of the core wire to the inner peripheral surface of the belt body. More than 98% and less
The reinforcing sheet has a structure in which fiber bundles in which a plurality of high-strength fibers are aligned are crossed and arranged, and is composed of a high-strength fiber sheet having a woven structure or a knitted structure.
The fiber bundle constituting the high-strength fiber sheet is composed of only aramid fibers or only carbon fibers.
When the high-strength fiber sheet has a structure in which the fiber bundles of the aramid fibers are arranged so as to cross each other, the thickness is 0.03 to 0.24 mm.
The high-strength fiber sheet, wherein when the fiber bundle of carbon fibers is arranged crossing structure, Ri thickness 0.05~0.09mm der,
The high-strength fiber sheet is a friction transmission belt characterized in that the tensile strength of the fiber bundles in two intersecting directions is 2000 N / mm ² or more. The friction transmission belt according to claim 1, wherein the cover sheet covers the entire circumference of the belt body and is composed of the high-strength fiber sheet. The friction transmission belt according to claim 1 or 2, wherein the reinforcing sheet is arranged so that the two intersecting directions of the fiber bundles are inclined with respect to the belt circumferential direction. The friction transmission belt according to claim 1 or 2, wherein the reinforcing sheet is arranged so that the two intersecting directions of the fiber bundles are the belt circumferential direction and the belt width direction. The friction transmission belt according to claim 2, wherein the cover sheet is arranged so that the two intersecting directions of the fiber bundles are inclined with respect to the peripheral direction of the belt. The friction transmission belt according to claim 2, wherein the cover sheet is arranged so that the two intersecting directions of the fiber bundles are orthogonal to the belt circumferential direction and the belt circumferential direction. The friction transmission belt according to any one of claims 1 to 6, wherein the maximum length in the belt width direction is 12 to 70 mm, and the belt thickness is 5 to 26 mm. The high-strength fiber sheet is
In the case of a structure in which fiber bundles of aramid fibers are arranged so as to intersect, the basis weight is 90 to 870 g / m ² .
The friction transmission belt according to claim 1 , wherein when the structure is such that the fiber bundles of carbon fibers are arranged so as to cross each other, the basis weight is 200 to 300 g / m ^2. The high-strength fiber sheet at least one of the reinforcing sheet and the cover sheet is according to any one of claims 1 to 8 , wherein the high-strength fiber sheet is subjected to an adhesive treatment for enhancing the adhesiveness with the rubber layer. Friction transmission belt.

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