Bearing device and swing arm assembly for magnetic disk
View Patent ↗A bearing device includes a shaft having an axis, plural rolling bearings arranged at axially separated positions and rotatably supporting the shaft, a first cylindrical member for supporting the rolling bearings therein and having a first screw on a part of an outer surface thereof, a second cylindrical member having a second screw engaging with the first screw on an inner surface thereof and mounted to the outer surface of the first cylindrical member by engaging the first screw with the second screw, a restricting member provided on the outer surface of the second cylindrical member for preventing relative axial movement of the second cylindrical member with respect to the first cylindrical member when a portion of the second member contacts the restricting member.
1. A bearing device comprising:
a shaft having an axis;
plural rolling bearings arranged at axially separated positions and rotatably supporting the shaft;
a first cylindrical member for supporting the rolling bearings on an inner surface thereof and having a first screw formed on an outer surface thereof;
a second cylindrical member having a second screw formed on an inner surface thereof and mounted to the outer surface of the first cylindrical member by engagement of the first screw with the second screw; and
a restricting member provided on the outer surface of the first cylindrical member for preventing relative axial movement of the second cylindrical member with respect to the first cylindrical member when a portion of the second cylindrical member contacts the restricting member, wherein
the first cylindrical member and the second cylindrical member form a sleeve assembly, and the sleeve assembly is supported by the plural rolling bearings and is relatively rotatable with respect to the shaft, and
the first screw and the second screw are fixed to each other by an adhesive.
2. The bearing device according to claim 1 , wherein a resonance frequency thereof is adjustable by adjusting a tightening torque of the second cylindrical member with respect to the first cylindrical member.
3. The bearing device according to claim 1 , wherein a gap is provided between the outer surface of the first cylindrical member and the inner surface of the second cylindrical member except for a portion in which the first screw and the second screw are engaged.
4. The bearing device according to claim 3 , wherein a resonance frequency thereof is adjustable by an adjustment of a tightening torque of the second cylindrical member with respect to the first cylindrical member, and a thickness of at least a part of a portion of the first cylindrical member forming the gap is changed, whereby an adjustable range of resonance frequency is obtained.
5. A swing arm assembly for a magnetic disc, comprising:
a swing arm for the magnetic disc; and
a bearing device according to claim 1 rotatably supporting the swing arm.
6. A swing arm assembly for a magnetic disc, comprising:
a swing arm for the magnetic disc; and
a bearing device according to claim 1 rotatably supporting the swing arm;
wherein an end portion of a screw for mounting the swing arm to the bearing device contacts the outer surface of the second cylindrical member.
7. The bearing device according to claim 1 , wherein the second cylindrical member is composed of one member.
8. The bearing device according to claim 1 , wherein the restricting member of the first cylindrical member is a flange provided at one end side of the outer surface of the first cylindrical member,
the first screw of the first cylindrical member is formed at another end side of the outer surface of the first cylindrical member,
the portion of the second cylindrical member is an end surface of one end side of the second cylindrical member, and
when a tightening torque is increased and the second cylindrical member is strongly tightened to the first cylindrical member, the end surface of one end side of the second cylindrical member presses the flange of the one end side of the first cylindrical member toward a direction directed from the another end side to the one end side of the first cylindrical member.
9. The bearing device according to claim 4 , wherein a groove is provided at the outer surface of the first cylindrical member, and the thickness of the first cylindrical member is adjusted by the groove of the first cylindrical member.
10. A bearing device comprising:
a shaft having an axis;
plural rolling bearings arranged at axially separated positions and rotatably supporting the shaft;
a first cylindrical member for supporting the rolling bearings on an inner surface thereof and having a first screw formed on an outer surface thereof;
a second cylindrical member having a second screw formed on an inner surface thereof and mounted to the outer surface of the first cylindrical member by engagement of the first screw with the second screw; and
a restricting member provided on the outer surface of the first cylindrical member for preventing relative axial movement of the second cylindrical member with respect to the first cylindrical member when a portion of the second cylindrical member contacts the restricting member, wherein
the first cylindrical member and the second cylindrical member form a sleeve assembly, and the sleeve assembly is supported by the plural rolling bearings and is relatively rotatable with respect to the shaft,
the second cylindrical member is composed of one member,
the restricting member of the first cylindrical member is a flange provided at one end side of the outer surface of the first cylindrical member,
the first screw of the first cylindrical member is formed at another end side of the outer surface of the first cylindrical member,
the portion of the second cylindrical member is an end surface of one end side of the second cylindrical member, and
when a tightening torque is increased and the second cylindrical member is strongly tightened to the first cylindrical member, the end surface of one end side of the second cylindrical member presses the flange of the one end side of the first cylindrical member toward a direction directed from the another end side to the one end side of the first cylindrical member.
11. The bearing device according to claim 10 , wherein a resonance frequency thereof is adjustable by adjusting the tightening torque of the second cylindrical member with respect to the first cylindrical member.
12. The bearing device according to claim 10 , wherein a gap is provided between the outer surface of the first cylindrical member and the inner surface of the second cylindrical member except for a portion in which the first screw and the second screw are engaged.
13. The bearing device according to claim 12 , wherein a resonance frequency thereof is adjustable by an adjustment of the tightening torque of the second cylindrical member with respect to the first cylindrical member, and a thickness of at least a part of a portion of the first cylindrical member forming the gap is changed, whereby an adjustable range of resonance frequency is obtained.
14. A swing arm assembly for a magnetic disc, comprising:
a swing arm for the magnetic disc; and
a bearing device according to claim 10 rotatably supporting the swing arm.
15. A swing arm assembly for a magnetic disc, comprising:
a swing arm for the magnetic disc; and
a bearing device according to claim 10 rotatably supporting the swing arm;
wherein an end portion of a screw for mounting the swing arm to the bearing device contacts the outer surface of the second cylindrical member.
16. The bearing device according to claim 10 , wherein the first screw and the second screw are fixed to each other by an adhesive.
17. The bearing device according to claim 13 , wherein a groove is provided at the outer surface of the first cylindrical member, and the thickness of the first cylindrical member is adjusted by the groove of the first cylindrical member.
18. A bearing device comprising:
a shaft having an axis;
plural rolling bearings arranged at axially separated positions and rotatably supporting the shaft;
a first cylindrical member for supporting the rolling bearings on an inner surface thereof and having a first screw formed on an outer surface thereof;
a second cylindrical member having a second screw formed on an inner surface thereof and mounted to the outer surface of the first cylindrical member by engagement of the first screw with the second screw;
a restricting member provided on the outer surface of the first cylindrical member for preventing relative axial movement of the second cylindrical member with respect to the first cylindrical member when an end surface of one end side of the second cylindrical member contacts the restricting member; and
a slit provided at an end surface of another end side of the second cylindrical member, wherein
the first cylindrical member and the second cylindrical member form a sleeve assembly, and the sleeve assembly is supported by the plural rolling bearings and is relatively rotatable with respect to the shaft, and
the slit of the second cylindrical member is adapted to receive an end portion of a torque driver, such that a tightening torque of the second cylindrical member with respect to the first cylindrical member can be adjusted by the torque driver to thereby adjust a resonance frequency of the bearing device.