| 摘要 |
<p>PURPOSE:To improve the durability of bellows made of thin metallic sheets to be used for a suspension device, etc., for vehicles by previously subjecting the outside surface side of the peak parts of the bellows and the inside surface side of the valley parts thereof to a surface hardening treatment by nitriding, etc., then striking the same with solid particles such as glass beads to generate compressive residual stresses. CONSTITUTION:A bellows body 12 made of the thin metallic sheets is provided between a metallic housing 2 and inside cylinder 18 of a suspension device 1 for vehicles. The metallic bellows body 12 is made of, for example, the thin metallic sheets of 0.1-0.3mm and is previously subjected to a nitriding treatment by gas nitriding or soft nitriding so that a hardened layer is formed thereon. Nozzles 29 are alternately disposed to open ends 12a, 12b at both sides of the bellows body and while the bellows 12 is rotated, the glass beads are blown to the inside peripheral face. The glass beads are blown from a nozzle 29 to the outside peripheral face of the bellows 12 in the contracted state. The compressive residual stresses are generated in the outside circumferential peak parts 14 and inside circumferential valley parts 15 of the bellows by this treatment. The wear resistance of the peak parts 14 which come into sliding contact with the inside wall surfaces of the housing 2 and the valley parts 15 which come into sliding contact with the outside peripheral faces of the inside cylinder 18 is thereby improved and the durability of the bellows is improved.</p> |
