The present invention relates to a core wire for a frictional power-transmission belt, the core wire including a Lang lay cord, having a total fineness of 300 to 1000 tex, and including a rubber component adhered to at least a part of a surface of the core wire, in which the Lang lay cord comprises a first-twisted yarn, and in which the first-twisted yarn comprises a carbon fiber.

The present invention relates to a core wire for a frictional power-transmission belt, the core wire including a Lang lay cord, having a total fineness of 300 to 1000 tex, and including a rubber component adhered to at least a part of a surface of the core wire, in which the Lang lay cord comprises a first-twisted yarn, and in which the first-twisted yarn comprises a carbon fiber.

A friction transmission belt includes a compression layer forming a pulley contact portion, the compression layer includes an inner layer formed from a rubber composition and an outer layer provided on a pulley contact side of the inner layer and formed from a fiber member, and a ratio (M10 modulus/M50 modulus) of an modulus at 10% elongation in a belt longitudinal direction (M10 modulus) to an modulus at 50% elongation in the belt longitudinal direction (M50 modulus), of the rubber composition, is not less than 1.5.

The frictional power transmission belt includes a frictional power transmission surface formed of a composite fibrous layer containing a fibrous member, an isocyanate compound, and a resin component, wherein the fibrous member contains a cellulose-based fiber. A proportion of each of the isocyanate compound and the resin component in the composite fibrous layer may be 2 to 15% by mass.

The frictional power transmission belt includes a frictional power transmission surface formed of a composite fibrous layer containing a fibrous member, an isocyanate compound, and a resin component, wherein the fibrous member contains a cellulose-based fiber. A proportion of each of the isocyanate compound and the resin component in the composite fibrous layer may be 2 to 15% by mass.

The present invention relates to a core wire for a frictional power-transmission belt, the core wire including a Lang lay cord, having a total fineness of 300 to 1000 tex, and including a rubber component adhered to at least a part of a surface of the core wire, in which the Lang lay cord comprises a first-twisted yarn, and in which the first-twisted yarn comprises a carbon fiber.

The present invention relates to a core wire for a frictional power-transmission belt, the core wire including a Lang lay cord, having a total fineness of 300 to 1000 tex, and including a rubber component adhered to at least a part of a surface of the core wire, in which the Lang lay cord comprises a first-twisted yarn, and in which the first-twisted yarn comprises a carbon fiber.

A high efficiency belt having reduced bending stiffness while maintaining a high coefficient of friction. The belt includes a backing layer, a rib material layer, and cords embedded within, wherein the coefficient of friction of the high efficiency belt is greater than or equal to 0.03 mm/N times the bending stiffness for belts having a thickness in the range of from 2.6 mm to 4.2 mm. The belt can include a bending stiffness in the range of from about 30 N/mm to about 65 N/mm and an anisotropic modulus of elasticity ratio of between 1.1 and 5.0. Methods of manufacturing the high efficiency belt are also described and can include forming sheets of rib material with parallel aligned reinforcement fibers transverse to the direction of rotation of the high efficiency belt.

The present invention relates to a V-ribbed belt that has a medium elongation of 0.8% or more when the load of 4 cN/dtex is applied, and that contains a twisted cord in which a high-elongation aramid fiber having a tensile modulus of 50-100 GPa and a low-modulus fiber having a lower tensile modulus than the high-elongation aramid fiber are blended and twisted.

The present invention relates to a V-ribbed belt that has a medium elongation of 0.8% or more when the load of 4 cN/dtex is applied, and that contains a twisted cord in which a high-elongation aramid fiber having a tensile modulus of 50-100 GPa and a low-modulus fiber having a lower tensile modulus than the high-elongation aramid fiber are blended and twisted.