Patent ID: 7489056
Filing Date: 2009-02-10
Classification: B21K,B23P,F16D,G11B,H02K,Y10T

Abstract:
1. A bonded body composed of a bonding member and a member to be bonded, which are used in a device for rotating the bonding member on which rotary disks are stacked, with the member to be bonded serving as a rotary shaft, wherein: the bonding member has a bonding hole into which a fitting portion of the member to be bonded is insertable, with a first bonding mark, in the form of a first annular depression around the bonding hole, being formed on an axial face of the bonding member in a vicinity of the bonding hole, and a second bonding mark, in the form of a second annular depression around the bonding hole being formed at the bottom of the first bonding marks; formation of the first bonding mark causes a flow of the material of the bonding member in the vicinity of the bonding hole towards the fitting portion of the member to be bonded, to integrate the member to be bonded and the bonding member, a portion of the bonding member in the vicinity of the fitting portion of the member to be bonded being pressurized at a load that is in excess of an elastic limit of the material of the bonding member, for generating a stress that is sufficient to plastically deform the material of the bonding member, to effect preliminary plastic bonding; and in formation of the second bonding mark, a compression force in an axial direction of the member to be bonded is applied to the portion of the bonding member in the vicinity of the the bonding hole, such that part of the material of the bonding member in the vicinity of the bonding hole is allowed to plastic-flow so as to fill a groove defined between the member to be bonded and the bonding member; whereby the bonding member and the member to be bonded are tightly integrated with each other, with the first and second bonding marks remaining on the completed bonded body.