Dynamic pressure air bearing

TLDR: In this paper, a bearing face is formed on the inner peripheral surface of a bearing body formed of a sintered alloy into a porous cylindrical shape, and the bearing face has a first dynamic pressure generating area m1 with a plurality of dynamic pressure grooves 5 inclined in one direction in relation to an axial direction and arranged in a circumferential direction.

Abstract: PROBLEM TO BE SOLVED: To provide a low-cost bearing of high accuracy by forming the bearing of a sintered alloy, providing a bearing face opposed to the outer peripheral surface of a shaft through a clearance, and inclined dynamic pressure grooves formed on the bearing face, and levitating to support the shaft by dynamic pressure action of air in the clearance. SOLUTION: A bearing face 4 opposed to the outer peripheral surface of a shaft through a bearing clearance is formed on the inner peripheral surface of a bearing body 1 formed of a sintered alloy into porous cylindrical shape. The bearing face 4 has a first dynamic pressure generating area m1 with a plurality of dynamic pressure grooves 5 inclined in one direction in relation to an axial direction and arranged in a circumferential direction, a second dynamic pressure generating area M2 axially separated from the first area M1 and having a plurality of dynamic pressure grooves inclined in the other direction in relation to the axial direction and arranged in the circumferential direction, and an annular smooth part (n) formed between both areas M1, m2. Air is collected to the smooth part (n) by the relative rotation of the shaft and bearing body 1, and dynamic pressure at this part is heightened. Bearing rigidity is increased because of no dynamic pressure groove in the smooth part (m). The grooves 5 can be formed by compression molding so as to reduce cost, and thermal deformation is small because of the sintered alloy so as to be able to maintain high accuracy even under high temperature.