| 摘要 |
PROBLEM TO BE SOLVED: To provide an auto tensioner capable of responding to a requirement of weight reduction and to reduce number of part items. SOLUTION: This auto tensioner comprises main components such as a fixing case 1 having shaft part 1a and bolt through holes 1e and 1f, an oscillating arm 2 in which a boss part 2a is engaged with the outside of the shaft part 1a of the fixing case 1 and oscillatingly mounted, a tension pulley 3 turnably mounted to the tip of the oscillating arm 2, a plain bearing 4 interposed between the shaft part 1a of the fixing case and the boss part 2a of the oscillating arm, and a torsion coil spring 5 mounted between the fixing case 1 and the oscillating arm 2 for energizing the oscillating arm 2 in one oscillation direction. The fixing case 1 is formed as a synthetic resin made molded article, thereby lightening the auto tensioner. Reinforcing metal cylinder 11a and 11b are disposed on the inner peripheral surfaces of the bolt through holes 1e and 1f and reinforced, and the plain bearing 4 is integrally molded with the outer peripheral surface of the shaft part 1a of the fixing case 1 using the synthetic resin to reduce the number of part items.
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