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US 2019/0078617 A1Published application
Dynamic pressure bearing and method for manufacturing same
AssigneeNtn Corporation
InventorKazuyoshi HARADA
Life of this patent
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Abstract
The fluid dynamic bearing including: a pair of bearing surfaces (8a1 and 8a2) having dynamic pressure generating grooves (G1 and G2) on an inner peripheral surface (8a); a pair of first smooth surfaces (8a4 and 8a5) formed between both the bearing surfaces (8a1 and 8a2) so as to be adjacent to the respective bearing surfaces (8a1 and 8a2); and a relief portion (8a3), which is formed between both the first smooth surfaces (8a4 and 8a5), and has a diameter larger than those of the pair of bearing surfaces (8a1 and 8a2).
Claims13
A fluid dynamic bearing, comprising:
- an inner peripheral surface comprising:
- a pair of bearing surfaces, which are formed in two regions separated from each other in an axial direction, and have dynamic pressure generating grooves;
- a pair of first smooth surfaces formed between the pair of bearing surfaces so as to be adjacent to the respective bearing surfaces;
- and
- a relief portion formed between the pair of first smooth surfaces, and has a diameter larger than a diameter of the pair of bearing surfaces;
- and
- an outer peripheral surface having pressure marks formed in entire axial regions covering the pair of bearing surfaces and the pair of first smooth surfaces.
4 more elements
A method of manufacturing a fluid dynamic bearing, comprising:
- inserting a core rod along an inner periphery of a bearing preform having a cylindrical shape, the core rod comprising a pair of molding patterns separated from each other in an axial direction and a first cylindrical region formed between the pair of molding patterns so as to be adjacent to the respective molding patterns, which are formed on an outer peripheral surface of the core rod;
- and
- pressing two regions of an inner peripheral surface of the bearing preform, which are separated from each other in the axial direction, against the molding patterns and the first cylindrical region of the core rod by pressing two regions of an outer peripheral surface of the bearing preform, which are separated from each other in the axial direction, radially inward to mold, on the inner peripheral surface of the bearing preform, a pair of bearing surfaces having dynamic pressure generating grooves and a pair of first smooth surfaces formed between the pair of bearing surfaces so as to be adjacent to the respective bearing surfaces, and to form a relief portion between the pair of first smooth surfaces, the relief portion having a diameter larger than a diameter of the pair of bearing surfaces.
Dependencies are inferred from the claim text.