Loading patent…
AssigneeHitachi, Ltd.
InventorsYuji Yoshitomi, Zensuke Tamura, Hideaki Kamohara, Keiji Omura, Yoshimasa Murakami, Tadasi Takata, Teruo Nuwa
Estimating the term…
A tube-hole structure for an expanded tube-to-tube-sheet joint which is formed by axially moving a rod within each tube member in each tube hole of the tube sheet by external drive means, thereby imparting an elastic mass placed inside the tube with a sufficient compressive load to expand the tube uniformly in the radial direction to provide a rigid joint between the tube and tube hole, characterized in that each tube hole has at least one circumferential groove with an axial dimension or length of 1.5/.beta. to 3.0/.beta. (.beta. being ##EQU1## WHERE R is the mean radius of the tube member to be expanded, t is the wall thickness of the tube, and .nu. is the Poisson's ratio).
A tube-hole structure for an expanded tube-to-tube-sheet joint wherein at least one circumferential groove is formed on the surrounding wall of each tube hole of a sheet into which each tube member is inserted and uniformly expanded to provide a joint, characterized in that the axial dimension of each said groove is in the range from about 1.5/.beta. to about 3.0/.beta. (.beta. being calculated from ##EQU7## wherein R is the mean radius of the tube member to be expanded, t is the wall thickness of the tube member, and .nu. is the Poisson's ratio).
A method of manufacturing a tube-hole structure for an expanded tube-to-tube-sheet joint comprising the steps of:
Dependencies are inferred from the claim text.