Patent ID: 6733406
Filing Date: 2004-05-11
Classification: F16H

Abstract:
A variable-speed V-belt drive for a vehicle with an engine, comprising:a drive pulley mounted on a drive shaft; a thrusting mechanism mounted on the drive shaft and capable of exerting thrust to the drive pulley to vary effective pitch diameter of the drive pulley; a driven pulley mounted on a driven shaft, the driven pulley including a fixed sheave fixedly mounted on the driven shaft and a movable sheave, the fixed sheave being integrally provided with a cylindrical shaft, the movable sheave being mounted on the cylindrical shaft so that the movable sheave can rotate and axially move on the cylindrical shaft; a V belt extended between the drive pulley and the driven pulley; and a pressure mechanism of applying pressure to the movable sheave of the driven pulley, the pressure mechanism including a helical cam groove formed in one of the cylindrical shaft and the movable sheave of the driven pulley, and a roller mounted on other of the cylindrical shaft and the movable sheave of the driven pulley so that the roller engages with the cam groove, the cam groove having opposite side surfaces respectively serving as a first working surface with which the roller engages when the vehicle travels in an engine-driving mode in which the driven shaft is driven by the driven pulley and a second working surface with which the roller engages when the vehicle travels in an engine-braking mode in which the driven pulley is driven by the driven shaft, the second working surface of the cam groove having at a predetermined position in an axial direction a retaining surface that restricts movement of the roller toward a low reduction ratio side when the vehicle travels in the engine-braking mode.