US 6,637,248 B2Granted

Method for machining protuberance of special-shaped tube

AssigneeSakamoto Industry Co., Ltd.

InventorsAkira Ishii, Akihiro Endo

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Abstract

A revolution center line (C) of a roll (R) is made eccentric with respect to an axis (L) of an elliptic tube (1). The eccentric amount ε is set such that when the revolution radius of the roll (R) is gradually reduced from a state in which the roll (R) is not in contact with any part of the elliptic tube (1), the roll (R) contacts one (4) of the two protuberances (4, 4) which is located on the opposite side to the eccentric direction generally earlier than any other part of the eccentric tube (1). The roll (R) is revolved and reciprocally moved in a direction of the revolution center line (C). At least at one end portion of the reciprocal movement, the roll (R) is moved towards the revolution center line (C) side. By repeating this procedure, the roll (R) is press contacted with the first-mentioned protuberance (4) so as to crush it for elimination.

Claims7

Dependent claims

A machining method for reducing, by spinning, an amount of projection of a first of two protuberances of a special shaped tube comprising steps of:

mounting a flattened tube stock part of a sectional configuration having a short axis and a long axis and a reduced-diameter part of a circular sectional configuration,
said reduced-diameter part being formed at one end portion of said tube stock part by spinning which is executed by revolving a forming tool with respect to said tube stock part, and
said two protuberances being formed on two intersection parts between an outer peripheral portion in the short axis direction of said tube stock part and an outer peripheral portion of said reduced diameter part, and projecting outward in the short axis direction;
mounting said forming tool for the spinning with respect to said special shaped tube about a revolution center line;
locating the revolution center line offset from a center between said two protuberances in an eccentric direction towards a second of said two protuberances;
and
press contacting said forming tool with only said first of said two protuberances located with respect to the center between said two protuberances in a direction opposite to the eccentric direction so as to spin only said first of said two protuberances.

4 more elements

Dependencies are inferred from the claim text.