Patent ID: 6402385
Filing Date: 2002-06-11
Classification: F16C

Abstract:
A dynamic pressure bearing apparatus comprising:a rotary shaft; and a sintered oil retaining bearing rotatably supporting the rotary shaft, the sintered oil retaining bearing having an interior surface defining an internal surface configuration for generating dynamic pressure to thereby form a dynamic pressure bearing between the rotary shaft and the sintered oil retaining bearing, wherein the internal surface of the sintered oil retaining bearing comprises in a peripheral direction thereof: a minimum-gap section having a minimum gap between the rotary shaft and the internal surface of the sintered oil retaining bearing; a large-gap section continuous to the minimum-gap section, the large-gap section having a larger gap between the rotary shaft and the sintered oil retaining bearing than that at the minimum-gap section to thereby increase pressure of lubrication oil that is present between the rotary shaft and the sintered oil retaining bearing toward the minimum-gap section; and a separation groove section between the large-gap section and the minimum-gap section, the separation groove section having a gap greater than that of the large-gap section, wherein the internal surface of the sintered oil retaining bearing is provided with a plurality of dynamic pressure bearing surface sections, each being defined by the minimum-gap section and the large-gap section, the minimum-gap is located, in the peripheral direction, at a predetermined angular position with respect to a boundary between the separation groove section and the dynamic pressure bearing surface section in a manner that a ratio of an arc angle defined by the dynamic pressure bearing surface section to the predetermined angular position of the minimum-gap section is set between 1:0 and 1:0.2, and a maximum gap in the large-gap section is two times or less greater than a minimum gap at the minimum-gap section.