| 摘要 |
PROBLEM TO BE SOLVED: To actuate a bearing as a dynamic pressure bearing when hydraulic oil supply is cut off so as to dispense with an auxiliary hydraulic oil source for protecting a rotary shaft by arranging an axis directional land part, which is arranged in the axis direction of a bearing pocket and ranges so as to be limiting an angle clamped from the shaft center, just below the shaft center in the vertical surface. SOLUTION: In a land part 4 in the boundary between a bearing pocket 2 and a bearing pocket 2, an angle clamping its both edges from the center of a rotary spindle 3 is limited to about 20-30 deg., and in addition, the land part 4 is arranged at a bearing clearance (m) of several 10μm to the rotary spindle 3. The axis directional land part 4 between the bearing pockets 2 is arranged so as to be positioned right below the shaft center in the vertical surface. Moreover, an oil recovering chamber 5 recovering oil flowing out from the bearing pockets 2 is arranged between two static pressure radial bearings A, A arranged in a bearing metal 1. Therefore, a large quantity of the leakage oil filling the oil recovering chamber 5 serves as lubrication oil so as to work in the similar wag to an impregnated type bearing in a dynamic pressure bearing when hydraulic oil supply to be fed to the bearing pockets 2 is cut off.
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