| 摘要 |
PROBLEM TO BE SOLVED: To prevent a defect from occurring due to a reduction in tension to zero without setting an initial belt tension so high by suppressing a reduction in the minimum tension on a belt 13 loose side when a damping resistance is increased by imparting a magnetic force to a magnetic viscous fluid MRF in an auto tensioner 16 capable of providing a damping force by the viscous resistance of a magnetic viscous fluid MRF. SOLUTION: The damper 24 of the auto tensioner 16 suppresses the vibration of an arm 18 by the viscous resistance of the magnetic viscous fluid MRF. An electronic magnet 34 imparting a magnetic force to the magnetic viscous fluid MRF by excitation is installed on the damper 24. When a variation in the rotation of an engine 1 is varied more than a predetermine level (YES in step S2) and a tension pulley 21 is moved in an anti-pressing direction (direction A) in which the tension pulley is pressed by a belt 13, the magnetic force is imparted to the magnetic viscous fluid MRF by the excitation of the electromagnet 34 of the damper 24 to increase the viscous resistance of the magnetic viscous fluid MRF so as to increase a damping force (damping resistance) (step S5). COPYRIGHT: (C)2006,JPO&NCIPI
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