Abstract: Each steel element for a V-belt of a continuously variable transmission has a flank (4a) that comprises a plurality of equally spaced raised portions (41) each being placed between two fine grooves (42). A flat flatness ratio (FR) given by the equation (1) is set to the highest one of values that are capable of practically machining the flank (4a) of the steel element (4) and capable of causing the flank (4a) to exhibit a given and satisfied lubrication oil discharging effect, and a groove pitch (GP) that is a distance between the two fine grooves (42) is set to a value that is capable of practically machining the flank of the steel element and capable of causing the flank to exhibit a given and satisfied lubrication oil discharging effect. The groove pitch thus set is a value that is permitted by the higher value of the flatness ratio thus set. FR (%)=WRP/(WRP+WG)×100??(1) wherein: FR: Flatness ratio WRP: Width of the raised portion (41) WG: Width of the groove (42).

Abstract: Under control of rotation of a crankshaft 41, a friction roller 32 is pressed against a friction roller 31 in a radial direction, so as to achieve torque transmission between the rollers 31, 32. An inter-roller radial pressing reaction is canceled as an internal force in bearing supports 23, 25, with no input to a housing 11. The reaction causes a radial displacement of a bearing-fitting portion provided with inner and outer bearings 21, 42 in double layer arrangement, wherein the radial displacement is larger than that of a bearing-fitting portion provided with a bearing 18, 19, 22 in single arrangement, so as to cause unbalanced contact between rollers 31, 32. In order to prevent this, support stiffness of bearing support 23 against the inter-friction-roller radial pressing reaction is set higher than that of bearing support 25.

Abstract: Under control of rotation of a crankshaft 41, a friction roller 32 is pressed against a friction roller 31 in a radial direction, so as to achieve torque transmission between the rollers 31, 32. An inter-roller radial pressing reaction is canceled as an internal force in bearing supports 23, 25, with no input to a housing 11. The reaction causes a radial displacement of a bearing-fitting portion provided with inner and outer bearings 21, 42 in double layer arrangement, wherein the radial displacement is larger than that of a bearing-fitting portion provided with a bearing 18, 19, 22 in single arrangement, so as to cause unbalanced contact between rollers 31, 32. In order to prevent this, support stiffness of bearing support 23 against the inter-friction-roller radial pressing reaction is set higher than that of bearing support 25.

Abstract: Each steel element for a V-belt of a continuously variable transmission has a flank (4a) that comprises a plurality of equally spaced raised portions (41) each being placed between two fine grooves (42). A flat flatness ratio (FR) given by the equation (1) is set to the highest one of values that are capable of practically machining the flank (4a) of the steel element (4) and capable of causing the flank (4a) to exhibit a given and satisfied lubrication oil discharging effect, and a groove pitch (GP) that is a distance between the two fine grooves (42) is set to a value that is capable of practically machining the flank of the steel element and capable of causing the flank to exhibit a given and satisfied lubrication oil discharging effect. The groove pitch thus set is a value that is permitted by the higher value of the flatness ratio thus set.