Title:
RACK AND PRODUCTION METHOD THEREOF
Document Type and Number:
WIPO Patent Application WO/2008/053896
Kind Code:
A1
Abstract:
A light-weight structure capable of sufficiently ensuring any of the width size,
strength and rigidity of a rack tooth (10), and a production method thereof. A
rack tooth (10) is formed by plastic working on one side surface in the radial direction
of a part in the axial direction of a sectionally circular rod unit (9). The radius
of curvature of the section shape of a portion deviated in the circumferential
direction from a rack-tooth (10) forming portion is set to be larger than the radius
of curvature of the section shape of an outer circumferential surface of the remaining
part in the axial direction of the rod unit (9). For this purpose, as shown by (A)→(B),
the part in the axial direction and the remaining part in the circumferential
direction are formed into a partially cylindrical surface portion (17) having
a radius of curvature larger than that of the outer circumferential surface of
a material (13) while a portion in the axial direction of the material (13) and
a portion in the circumferential direction are being crushed, thereby defining
an intermediate material (20).Then, as shown by (C)→(D), the above rack
tooth (10) is formed at a portion in the axial direction of the intermediate material
(20) and a portion in the circumferential direction. Finally, as shown by (E)→(F),
it is subjected to sizing to complete a rack (8).
Inventors:
KOBAYASHI KAZUTO (JP)
MIZUSHIMA YUKI (JP)
HIROTA KOTARO (JP)
TSUBOUCHI AKIRA (JP)
MIZUSHIMA YUKI (JP)
HIROTA KOTARO (JP)
TSUBOUCHI AKIRA (JP)
Application Number:
PCT/JP2007/071140
Publication Date:
May 08, 2008
Filing Date:
October 30, 2007
Export Citation:
Assignee:
NSK LTD (JP)
KOBAYASHI KAZUTO (JP)
MIZUSHIMA YUKI (JP)
HIROTA KOTARO (JP)
TSUBOUCHI AKIRA (JP)
KOBAYASHI KAZUTO (JP)
MIZUSHIMA YUKI (JP)
HIROTA KOTARO (JP)
TSUBOUCHI AKIRA (JP)
International Classes:
B21K1/06; B21J5/02; B21J5/08; B21J5/12; B21K1/76; F16H55/26
Foreign References:
| JPS5813431A | 1983-01-25 | |||
| JPS5881535A | 1983-05-16 | |||
| JPS597456A | 1984-01-14 | |||
| JPS59104237A | 1984-06-16 | |||
| JPH0158081B2 | 1989-12-08 | |||
| JP2001079639A | 2001-03-27 | |||
| JP3442298B2 | 2003-09-02 | |||
| JP2006103644A | 2006-04-20 | |||
| JP2007056867A | 2007-03-08 |
Other References:
See also references of EP 2082818A4
Attorney, Agent or Firm:
KAMODA, Tetsuaki (Nishi-Shimbashi, Minato-ku Tokyo 03, JP)
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