公开(公告)号：JPH09282787A

公开(公告)日：1997-10-31

申请号：JP7485496

申请日：1996-03-28

Applicant: IBM

Inventor： SATO KIYOSHI ,  DEBITSUDO ARUBUREHITO ,  NEMOTO SUNAO

IPC: G11B19/20 ,  G11B17/022 ,  G11B33/08 ,  G11B33/14

Abstract: PROBLEM TO BE SOLVED: To reduce the deformation of a hub by providing a reduced stress region having an inner peripheral diameter of the hub in a part of a joined region larger than in other parts and reducing stress between the outer periphery of a sleeve and the inner periphery of the hub when a thermal expansion occurs because of a temperature change. SOLUTION: Because of a change in temperature, stress of vector A or B is produced in the full inner periphery of a hub, thus an imbalance occurs in a joined part between a hub 14 and a sleeve 11, distortion occurs in the hub and a thermal runout, that is, rotational shaking occurs in a disk loaded in the hub. The inner peripheral diameter of the center part of a joined region between the hub 14 and the sleeve 11 is larger than that of each of the upper and lower joined parts 24 and 25 of the joined region, thus a stress reducing region 23 is formed. In a left part V, a difference between the stress vectors A' and B' of the upper and lower ends of the reducing region is smaller than that between the vectors A and B. This is because no stress occurs between the hub 14 and the sleeve 11 caused by a linear expansion coefft. difference. By reducing the imbalance between the stress vectors, thermal runout is reduced.