A synchronous belt having a tensile member layer with a tensile member embedded in an elastomeric body, a toothed surface with a plurality of regularly spaced, transverse teeth protruding from the body, a jacket covering the toothed surface, and a unidirectional fabric layer suspended in the belt between the jacket and the tensile member layer and following the approximate contour of the jacket.

A synchronous belt having a tensile member layer with a tensile member embedded in an elastomeric body, a toothed surface with a plurality of regularly spaced, transverse teeth protruding from the body, a jacket covering the toothed surface, and a unidirectional fabric layer suspended in the belt between the jacket and the tensile member layer and following the approximate contour of the jacket.

The present invention relates to a helical toothed belt including: a back portion in which a tension member is buried; and a plurality of tooth portions, in which: the plurality of tooth portions have a tooth pitch of 2 mm or more and less than 4 mm, in a case where the tooth pitch of the plurality of tooth portions is 2 mm or more and less than 3 mm, the back portion has a thickness of 0.4 mm or more and 1.2 mm or less, in a case where the tooth pitch of the plurality of tooth portions is 3 mm or more and less than 4 mm, the thickness of the back portion is 0.6 mm or more and 1.8 mm or less; and the tension member is a twisted cord including a high-strength glass fiber or a carbon fiber.

The present invention relates to a helical toothed belt including: a back portion in which a tension member is buried; and a plurality of tooth portions, in which: the plurality of tooth portions have a tooth pitch of 2 mm or more and less than 4 mm, in a case where the tooth pitch of the plurality of tooth portions is 2 mm or more and less than 3 mm, the back portion has a thickness of 0.4 mm or more and 1.2 mm or less, in a case where the tooth pitch of the plurality of tooth portions is 3 mm or more and less than 4 mm, the thickness of the back portion is 0.6 mm or more and 1.8 mm or less; and the tension member is a twisted cord including a high-strength glass fiber or a carbon fiber.

A cover fabric for a power transmission belt, the fabric woven from warp yarns and weft yarns; the warp yarns and weft yarns each plied from a first filament yarn and a second filament yarn; the first filament yarn comprising higher tensile strength fibers than the second filament yarn; and the fabric woven in a modified twill pattern. A toothed belt with the cover fabric on the teeth, oriented on a bias, with the fabric having a bias angle less than 90.

A cover fabric for a power transmission belt, the fabric woven from warp yarns and weft yarns; the warp yarns and weft yarns each plied from a first filament yarn and a second filament yarn; the first filament yarn comprising higher tensile strength fibers than the second filament yarn; and the fabric woven in a modified twill pattern. A toothed belt with the cover fabric on the teeth, oriented on a bias, with the fabric having a bias angle less than 90.

A synchronous belt drive system having: a synchronous belt with a tensile cord of high-modulus fiber such as glass, carbon, PBO, or aramid; a driver sprocket and at least one driven sprocket, at least one of which is an obround sprocket; and a tensioner having: a base having a cylindrical portion extending axially with a radially outer surface and a receiving portion, an eccentric arm pivotally engaged with the radially outer surface, a torsion spring disposed within the receiving portion, the torsion spring applying a biasing force to the eccentric arm, and a pulley journalled to the eccentric arm. Preferably, no one of the eccentric arm, pulley, or torsion spring is axially displaced along an axis A-A from the others. The obround sprocket has a toothed surface and at least one linear portion disposed between two arcuate portions having a constant radius, the linear portion having a predetermined length.

A synchronous belt drive system having: a synchronous belt with a tensile cord of high-modulus fiber such as glass, carbon, PBO, or aramid; a driver sprocket and at least one driven sprocket, at least one of which is an obround sprocket; and a tensioner having: a base having a cylindrical portion extending axially with a radially outer surface and a receiving portion, an eccentric arm pivotally engaged with the radially outer surface, a torsion spring disposed within the receiving portion, the torsion spring applying a biasing force to the eccentric arm, and a pulley journalled to the eccentric arm. Preferably, no one of the eccentric arm, pulley, or torsion spring is axially displaced along an axis A-A from the others. The obround sprocket has a toothed surface and at least one linear portion disposed between two arcuate portions having a constant radius, the linear portion having a predetermined length.

A resin belt includes: a plurality of teeth disposed at predetermined intervals along a longitudinal direction of the belt on a running surface of a belt body made of a thermoplastic resin; and a cloth covering the teeth, characterized in that: the cloth is a woven cloth obtained by weaving a thermoplastic synthetic resin fiber used as a warp yarn in the longitudinal direction of the belt and a fluorine resin fiber used as a weft yarn in a width direction of the belt; and a percentage of the fluorine resin fiber exposed on a side of a cloth surface of the teeth is 50% or more per unit area, and a percentage of the fluorine resin fiber exposed on a side of a bonded surface with the belt body is 50% or less per unit area.

A resin belt includes: a plurality of teeth disposed at predetermined intervals along a longitudinal direction of the belt on a running surface of a belt body made of a thermoplastic resin; and a cloth covering the teeth, characterized in that: the cloth is a woven cloth obtained by weaving a thermoplastic synthetic resin fiber used as a warp yarn in the longitudinal direction of the belt and a fluorine resin fiber used as a weft yarn in a width direction of the belt; and a percentage of the fluorine resin fiber exposed on a side of a cloth surface of the teeth is 50% or more per unit area, and a percentage of the fluorine resin fiber exposed on a side of a bonded surface with the belt body is 50% or less per unit area.