Patent ID: 7478951
Filing Date: 2009-01-20
Classification: F16C,H02K

Abstract:
1. A hydrodynamic bearing device, comprising: a fixed shaft; a base fixed to a first end portion of the shaft; a bearing body comprising a cylindrical sleeve, the bearing body surrounding an outer peripheral surface of the shaft and rotatably supported by the shaft; a hub fixed to the bearing body and having a hole therein, the shaft being located in said hole in said hub; at least one radial bearing having a first gap between the outer peripheral surface of the shaft and an inner peripheral surface of the bearing body and having a radial dynamic pressure generating groove in at least one of the outer peripheral surface of the shaft and the inner peripheral surface of the bearing body; a thrust bearing having a second gap between a first end face of the bearing body and the base and having a thrust dynamic pressure generating groove in at least one of a first end face of the bearing body and a surface of the base facing the first end face of the bearing body, the gaps of the radial bearing and the thrust bearing being connected and filled with an operating fluid; a slip-out preventing device for preventing the bearing body from slipping out in an axial direction away from the base past a predetermined point, the slip-out preventing device including a first side engaging part on the outer peripheral surface of the bearing body, said first side engaging part rotatable with the bearing body and comprising an outer collar part, and a fixed second side engaging part on the base, said fixed second side engaging part comprising an annular slip-out preventing member including an inner collar part on an inner periphery of the fixed second side engaging part, the second side engaging part for preventing the first side engaging part from slipping out in an axial direction away from the base, thereby preventing the bearing body from moving in such axial direction; a third gap between the outer collar part of the sleeve and the inner peripheral surface of the slip-out preventing member, the third gap connected to the second gap; wherein the hub is located on a second end face of the bearing body opposite the first end face of the bearing body; an annular inner groove located between the inner collar part and the base; the hub comprising a cover part covering the second end face of the bearing body along a periphery of the hole; a fourth gap connected to the first gap located between the cover part and the second end face of the bearing body; and operating fluid filling the third and fourth gaps.