Fluid dynamic bearing device

A fluid dynamic bearing device, comprising:

• a shaft member;
• a bearing member having the shaft member inserted along an inner periphery of the bearing member;
• and
• a radial dynamic pressure generating portion configured to support the shaft member in a relatively rotatable and non-contact manner with pressure of a fluid film formed in a radial bearing gap defined between an outer peripheral surface of the shaft member and an inner peripheral surface of the bearing member,
• wherein the radial dynamic pressure generating portion comprises:
• a plurality of polygonal hill portions pattern-arranged on any one of the inner peripheral surface of the bearing member and the outer peripheral surface of the shaft member;
• a same number of polygonal groove portions as the polygonal hill portions, each of the polygonal groove portions formed in such a manner as to surround the polygonal hill portions;
• and
• connection groove portions each configured to connect adjacent polygonal groove portions, and
• wherein a sectional area of one of the connection groove portions is set to be larger than a sectional area of one of the polygonal groove portions.