| 摘要 |
<p>Provided are a hollow coil spring and a method for manufacturing the hollow coil spring, whereby inner surface corrosion can be prevented, and product appearance can be improved. In an end sealing step, the core material of an end (Wa) of a spring material (W) is gathered by machining to seal the end (Wa). Spinning is preferably carried out as the form of machining. While pressing the end of the spring material (W) with a squeezing roller (R), for example, toward the inside in the radial direction, the squeezing roller (R) is appropriately moved in the axial direction as necessary. The end (Wa) of the spring material (W) is thus occluded, as shown in figure 3, eliminating the need to use a separate member such as a lid member. Such an end sealing step can be carried out immediately after an inner surface processing step, for example. In a coil forming step performed after the end sealing step, even if the end (Wa) of the spring material (W) is gripped and the spring material (W) is wrapped around a rod, the formation of a gap at the end (Wa) will be prevented.</p> |
