| 摘要 |
A device which maintains a predetermined tensioning force on the endless drive belt for vehicle accessories by use of a one-way clutch which prevents return of the tensioning means from its forwardmost tensioning position. In the preferred embodiment, a cylindrical shaft is mounted in a fixed position adjacent the drive belt. A roller clutch assembly is mounted on the shaft and includes an outer clutch housing rotatably mounted on the shaft. An outwardly extending lever is attached to the clutch housing and has an idler pulley rotatably mounted on the extended end of the lever. The pulley is moved into tensioning engagement with the drive belt by a torsional spring which is telescopically mounted on the shaft and clutch housing. The spring moves the pulley in a belt tensioning direction. The one-way clutch assembly preferably includes a roller clutch which consists of a plurality of rollers which are interposed between and are biased by a plurality of leaf springs into a wedging relationship with the shaft surface and ramps formed on a bearing cup. The rollers permit free movement of the clutch housing and attached lever in the belt tensioning direction while preventing movement of these components and associated idler pulley in the opposite nontensioning direction because of the wedging action of the rollers. |
