Impact resistant rotating device with increased-thickness portion relationship and suction plate configuration
In a disk drive device, a magnetic recording disk is mounted on a hub. A base rotatably supports the hub via a bearing unit. The base has a ring-shaped wall that surrounds the bearing unit and that protrudes towards the hub. A laminated core is fixed to the base. The laminated core has a ring portion and twelve teeth that radially outwardly extend from the ring portion. Coils are wound around the twelve teeth. The base includes an increasing-thickness portion formed so that the less the distance between a part of the increasing-thickness portion and the ring-shaped wall is, the thicker the part of the increasing-thickness portion becomes.
1. A rotating device, comprising:
a hub on which a recording disk is to be mounted;
a base rotatably supporting the hub via a bearing unit, the base having a ring-shaped wall that surrounds the bearing unit and that protrudes towards the hub;
a core fixed to the base, the core having a ring portion and a plurality of teeth that radially extend from the ring portion; and
coils wound around the plurality of teeth,
wherein the base includes an increasing-thickness portion formed so that the less the distance between a part of the increasing-thickness portion and the ring-shaped wall is, the thicker the part of the increasing-thickness portion becomes and so that the following equation is satisfied:
H
(
x
)
H
0
≥
k
(
x
x
0
)
-
1.2
(
equation
1
)
where x is a distance between a part of the increasing-thickness portion and a rotational axis of the hub, x 0 is a predetermined reference distance, H(x) is a thickness of the increasing-thickness portion at the distance x, H 0 is a predetermined reference thickness, and k is a predetermined constant greater than zero,
wherein the base includes a coil-facing portion provided radially-outside and adjacent to the increasing-thickness portion, the coil-facing portion facing the coil in an axial direction and having a predetermined constant thickness,
wherein the coils have a decreasing-thickness portion, the thickness of which decreases in accordance with a profile of the increasing-thickness portion, and
wherein a portion of the hub that faces the coils in the direction along the rotational axis of the hub is thicker than the coil-facing portion.
2. The rotating device according to claim 1 , wherein the coils are formed so that a distance between the coils and the increasing-thickness portion is greater than a predetermined distance.
3. The rotating device according to claim 1 , wherein the increasing-thickness portion is formed so that the hub maintains a predetermined height even if a test impact load of 1200 G is applied.
4. The rotating device according to claim 1 , wherein, when a coordinate is defined along the rotational axis of the hub, the coordinate range of the core at least partly overlaps the coordinate range of a portion where the bearing unit touches the ring-shaped wall.
5. The rotating device according to claim 1 , wherein a space on the hub-side of the base is filled with a gas, which includes a predetermined ratio of Helium, and
a through hole is provided on the base, and
a seal member is provided along an edge of the through-hole on a surface of the base opposite to the hub.
6. The rotating device according to claim 1 , further comprising a ring-shaped thrust ring, the center of which is along the rotational axis of the huh, the ring-shaped thrust ring being fixed to the hub, and
the thrust ring has a substantially flat hub-facing surface that faces the hub in the direction along the rotational axis of the hub, and
a part of the hub-facing surface is in contact with the hub and the other part, when the hub rotates, suppresses the motion of the hub in the direction along the rotational axis of the hub in cooperation with the bearing unit.
7. The rotating device according to claim 6 , wherein the thrust ring is made of a material, the hardness of which substantially is equal to that of the hub.
8. A rotating device, comprising:
a hub on which a recording disk is to be mounted;
a base rotatably supporting the hub via a bearing unit, the base having a ring-shaped wall that surrounds the bearing unit and that protrudes towards the hub;
a core fixed to the base, the core having a ring portion and a plurality of teeth that radially extend from the ring portion; and
coils wound around the plurality of teeth,
wherein the base includes an increasing-thickness portion formed so that the less the distance between a part of the increasing-thickness portion and the ring-shaped wall is, the thicker the part of the increasing-thickness portion becomes and so that the following equation is satisfied:
H
(
x
)
H
0
≥
k
(
x
x
0
)
-
1.2
(
equation
1
)
where x is a distance between apart of the increasing-thickness portion and a rotational axis of the hub, x 0 is a predetermined reference distance, H(x) is a thickness of the increasing-thickness portion at the distance x, H 0 is a predetermined reference thickness, and k is a predetermined constant greater than zero,
wherein the base includes a coil-facing portion provided radially-outside and adjacent to the increasing-thickness portion, the coil-facing portion facing the coil in an axial direction and having a predetermined constant thickness,
wherein the coils have a decreasing-thickness portion, the thickness of which decreases in accordance with a profile of the increasing-thickness portion, and
wherein, when a coordinate is defined along the rotational axis of the hub, the coordinate range of the core at least partly overlaps the coordinate range of a portion where the bearing unit touches the ring-shaped wall.
9. The rotating device according to claim 8 , wherein the coils are formed so that a distance between the coils and the increasing-thickness portion is greater than a predetermined distance.
10. The rotating device according to claim 8 , wherein the increasing-thickness portion is formed so that the hub maintains a predetermined height even if a test impact load of 1200 G is applied.
11. The rotating device according to claim 8 , further comprising a ring-shaped thrust ring, the center of which is along the rotational axis of the hub, the ring-shaped thrust ring being fixed to the hub, and
the thrust ring has a substantially flat hub-facing surface that faces the hub in the direction along the rotational axis of the hub, and
a part of the hub-facing surface is in contact with the hub and the other part, when the hub rotates, suppresses the motion of the hub in the direction along the rotational axis of the hub in cooperation with the bearing unit.
12. The rotating device according to claim 11 , wherein the thrust ring is made of a material, the hardness of which substantially is equal to that of the hub.
13. A rotating device, comprising:
a hub on which a recording disk is to be mounted;
a base rotatably supporting the hub via a bearing unit, the base having a ring-shaped wall that surrounds the bearing unit and that protrudes towards the hub;
a core fixed to the base, the core having a ring portion and a plurality of teeth that radially extend from the ring portion; and
coils wound around the plurality of teeth,
wherein a space above an increasing-thickness portion is filled with a gas, which includes a predetermined ratio of Helium,
wherein the base includes the increasing-thickness portion which is formed so that the less the distance between a part of the increasing-thickness portion and the ring-shaped wall is, the thicker the part of the increasing-thickness portion becomes and so that the following equation is satisfied:
H
(
x
)
H
0
≥
k
(
x
x
0
)
-
1.2
(
equation
1
)
where x is a distance between a part of the increasing-thickness portion and a rotational axis of the hub, x 0 is a predetermined reference distance, H(x) is a thickness of the increasing-thickness portion at the distance x, H 0 is a predetermined reference thickness, and k is a predetermined constant greater than zero,
wherein the base includes a coil-facing portion provided radially-outside and adjacent to the increasing-thickness portion, the coil-facing portion facing the coil in an axial direction and having a predetermined constant thickness,
wherein the coils have a decreasing-thickness portion, the thickness of which decreases in accordance with a profile of the increasing-thickness portion, and
wherein, when a coordinate is defined along the rotational axis of the hub, the coordinate range of the core at least partly overlaps the coordinate range of a portion where the bearing unit touches the ring-shaped wall.
14. The rotating device according to claim 13 , wherein the coils are formed so that the distance between the coils and the increasing-thickness portion is greater than a predetermined distance.
15. The rotating device according to claim 13 , wherein the increasing-thickness portion is formed so that the hub maintains a predetermined height even if a test pact load of 1200 G is applied.