Thrust dynamic pressure bearing, spindle motor using thereof, and information recording/reproducing device using the spindle motor
View Patent ↗A thrust dynamic pressure bearing with high inclination-resistant rigidity against axis runout and additionally low bearing loss torque is implemented. Herringbone grooves ( 131 ) having intermediate bends ( 132 ) are provided on rotating-side bearing surface ( 11 ) provided on the rotating-side bearing member. When rotating-side bearing surface ( 11 ) rotates in direction A (clockwise), lubricating oil generates dynamic pressure in an area centering on intermediate bend ( 132 ) along radially outer part ( 133 ) and radially inner part ( 134 ) of herringbone groove ( 131 ). As a result that groove width (G) of a dynamic pressure generating groove and width (L) of a land adjacent to the dynamic pressure generating groove holds G>L at an arbitrary radius ( 2 ) position, a thrust dynamic pressure bearing with high inclination-resistant rigidity and additionally low bearing loss torque is provided.
1. A thrust dynamic pressure bearing comprising:
a bearing surface of a rotating-side bearing member; and
a bearing surface of a fixed-side bearing member, both surfaces facing each other axiswise through a minute interspace, wherein
the minute interspace is filled with lubricating oil;
a plurality of dynamic pressure generating grooves are formed on at least one of the bearing surfaces of the rotating-side bearing member and the fixed-side bearing member;
rotation is retained by dynamic pressure of lubricating oil being induced by means of the dynamic pressure generating grooves according to rotation of the rotating-side bearing member; and
groove width G in a circumferential direction of rotation of the rotating-side bearing member, of the dynamic pressure generating groove; and width L in a circumferential direction of rotation of the rotating-side bearing member, of a land circumferentially adjacent to the dynamic pressure generating groove hold G>L in an area of 80% or more of the area in which the dynamic pressure generating grooves provided on the bearing surface are formed.
2. The thrust dynamic pressure bearing as claimed in claim 1 , wherein the dynamic pressure generating groove has a herringbone shape.
3. The thrust dynamic pressure bearing as claimed in claim 2 , wherein relationship between groove width G of the dynamic pressure generating groove and width L of a land circumferentially adjacent to the dynamic pressure generating groove ranges from G:L=65:35 to G:L=75:25.
4. The thrust dynamic pressure bearing as claimed in claim 1 , wherein the dynamic pressure generating groove has a spiral shape.
5. The thrust dynamic pressure bearing as claimed in claim 4 , wherein relationship between groove width G of the dynamic pressure generating groove and width L of a land circumferentially adjacent to the dynamic pressure generating groove ranges from G:L=65:35 to G:L=80:20.
6. A thrust dynamic pressure bearing comprising:
a bearing surface of a rotating-side bearing member; and
a bearing surface of a fixed-side bearing member, both surfaces facing each other axiswise through a minute interspace, wherein
the minute interspace is filled with lubricating oil;
a plurality of dynamic pressure generating grooves having a herringbone shape are formed on at least one of the bearing surfaces of the rotating-side bearing member and the fixed-side bearing member;
rotation is retained by dynamic pressure of lubricating oil being induced by means of the dynamic pressure generating grooves according to rotation of the rotating-side bearing member; and
relationship between groove width G in a circumferential direction of rotation of the rotating-side bearing member, of the dynamic pressure generating grooves; and width L in a circumferential direction of rotation of the rotating-side bearing member, of a land circumferentially adjacent to the dynamic pressure generating groove ranges from G:L=65:35 to G:L=75:25.
7. A thrust dynamic pressure bearing comprising:
a bearing surface of a rotating-side bearing member; and
a bearing surface of a fixed-side bearing member, both surfaces facing each other axiswise through a minute interspace, wherein
the minute interspace is filled with lubricating oil;
a plurality of dynamic pressure generating grooves having a spiral shape are formed on at least one of the bearing surfaces of the rotating-side bearing member and the fixed-side bearing member;
rotation is retained by dynamic pressure of lubricating oil being induced by means of the dynamic pressure generating groove according to rotation of the rotating-side bearing member; and
relationship between groove width G in a circumferential direction of rotation of the rotating-side bearing member, of the dynamic pressure generating groove and width L in a circumferential direction of rotation of the rotating-side bearing member, of a land circumferentially adjacent to the dynamic pressure generating groove ranges from G:L=65:35 to G:L=80:20.
8. A spindle motor comprising a thrust dynamic pressure bearing as claimed in any one of claims 1 through 7 .
9. An information recording and reproducing device comprising a spindle motor having a thrust dynamic pressure bearing as claimed in any one of claims 1 through 7 .