Abstract: A drive belt includes a foamed undercord layer having void spaces located throughout the foamed undercord layer. The void spaces extend from a backing layer of the undercord layer to an exterior surface of the backing layer, and may include some void spaces at the exterior surface that are open to the external environment. The foamed undercord layer may exhibit a 20% reduction in specific gravity as compared to an unfoamed version of the undercord layer. The manufacturing process for making the foamed undercord layer can include incorporating foaming agent in the undercord layer such that the undercord layer both foams and cures when heat and pressure are applied to the undercord layer. The foamed drive belt incorporating the foamed undercord layer may exhibit reduced bending stiffness and improved energy efficiency.

Abstract: A drive belt includes an undercord layer having a first region proximate a backing layer surface of the undercord layer and a second region proximate the exterior surface of the undercord layer, the first region being foamed and the second region either being foamed to a lesser extent than the first region or not being foamed. The drive belt further includes a cover layer formed over the exterior surface of the undercord layer. Alternatively, the drive belt may be foamed throughout the undercord layer thickness, with a cover layer formed on the exterior surface of the undercord layer. The manufacturing process for making the foamed undercord layer can include incorporating a first quantity of foaming agent in a first sheet of undercord layer material and either a second quantity of foaming agent in a second sheet of undercord layer material, the second quantity being less than the first quantity, or including no foaming agent in the second sheet.

Abstract: Compositions for material layers suitable for use in power transmission belts are described. The composition includes millable polyurethane, such as polyester-based millable polyurethane or polyether-based millable polyurethane, such that material layers formed from the composition are solid but pliable. The disclosed material layers can be used to form the main body portion of power transmission belts, such as synchronous belts, V-belts, and micro-V belts.

Abstract: A synchronous belt with a tensile member layer having a tensile member embedded in an elastomeric body; a toothed surface with a plurality of regularly spaced, transverse teeth protruding from the body; and a jacket covering the toothed surface; wherein the teeth comprise a plurality of fabric insert layers that increase the stiffness of the tooth, the insert layers separated from each other by layers of an elastomer composition. The layers may be oriented parallel to the tensile member layer, perpendicular to the tensile member, or following the contour of the tooth. The layers may be a single piece of fabric folded into layers, or separate pieces of fabric.

Abstract: A synchronous belt with a tensile member layer having a tensile member embedded in an elastomeric body; a toothed surface with a plurality of regularly spaced, transverse teeth protruding from the body; and a jacket covering the toothed surface; wherein the teeth comprise a plurality of fabric insert layers that increase the stiffness of the tooth, the insert layers separated from each other by layers of an elastomer composition. The layers may be oriented parallel to the tensile member layer, perpendicular to the tensile member, or following the contour of the tooth. The layers may be a single piece of fabric folded into layers, or separate pieces of fabric.