US Patent 7169072 Metal push belt and oil specification related thereto

A composite driving belt provided with a carrier and a plurality of transverse elements assembled slidably thereon, the carrier including one or more bands, preferably composed of a plurality of endless metal bands disposed radially around each other, each element being provided with a radially outward directed carrier contact plane for contacting a radial inner contact plane of the carrier while in operation, wherein the contact plane of both the carrier and the element have a non profiled surface. In particular the roughness and shape of the relevant contacting faces of a belt are adapted to achieve a hydrodynamic lubricating condition, while the lubricating oil is defined to meet the requirements of an improved efficiency push belt.