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Title:
HOLLOW COIL SPRING AND METHOD FOR MANUFACTURING SAME
Document Type and Number:
WIPO Patent Application WO/2012/073786
Kind Code:
A1
Abstract:
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.

Inventors:
YAJIMA, Takashi (10, Fukuura 3-chome, Kanazawa-ku, Yokohama-sh, Kanagawa 04, 〒2360004, JP)
矢嶋 隆 (〒04 神奈川県横浜市金沢区福浦3丁目10番地 日本発條株式会社内 Kanagawa, 〒2360004, JP)
Application Number:
JP2011/077055
Publication Date:
June 07, 2012
Filing Date:
November 24, 2011
Export Citation:
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Assignee:
NHK SPRING CO., LTD. (10 Fukuura 3-chome, Kanazawa-ku Yokohama-sh, Kanagawa 04, 〒2360004, JP)
日本発條株式会社 (〒04 神奈川県横浜市金沢区福浦3丁目10番地 Kanagawa, 〒2360004, JP)
YAJIMA, Takashi (10, Fukuura 3-chome, Kanazawa-ku, Yokohama-sh, Kanagawa 04, 〒2360004, JP)
International Classes:
B21D41/04; B21D22/14; B21F35/00; B21H1/18; F16F1/06
Foreign References:
JPS4728125U1972-11-30
JPS5665738U1981-06-02
JPS5933041A1984-02-22
JPS48101356A1973-12-20
JP2007127227A2007-05-24
Other References:
See also references of EP 2647449A4
Attorney, Agent or Firm:
SUENARI, Mikio (Asaco Kyobashi Building 3rd floor, 6-13 Kyobashi 1-chome, Chuo-k, Tokyo 31, 〒1040031, JP)
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Claims: