JP2000337367A - High speed spindle motor and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-speed spindle motor suppressing the deviation of a shaft and the deviation of a plane at high-speed rotation. SOLUTION: This spindle motor loosely fits a retainer 11 and a revolving shaft 7 inside of a bearing housing 1 attached at the center of a stator base 4. In the roller holding part of the retainer 11, the roller group 9 at the first row that revolves on the track at the first distance from the center of the rotation and also the roller group 10 at the second row that revolves on the track at the second distance from the center of the rotation are inserted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-speed spindle motor equipped with a rolling bearing for mounting and rotating a disk-shaped storage medium, and more particularly to a high-speed spindle motor having a long life and a roller bearing free from shaft runout and surface runout. It relates to a spindle motor.

[0002]

2. Description of the Related Art Conventionally, ball bearings are often used in rolling bearings used in high-speed spindle motors. However, when ball bearings are used as bearings, two points must be used on the output side and the opposite output side of the motor rotation shaft. In addition, the preloading method is complicated, and the workability is poor due to small balls. there were. Therefore, a configuration in which the periphery of the rotating shaft is held by roller bearings has been proposed. However, such a configuration in which the rollers are held by roller bearings has a large backlash, and particularly when the motor rotates at a high speed, there is a disadvantage that the rotors run out due to the backlash of the roller bearings and the surface runout. Hereinafter, this point will be described with reference to FIG. FIG.
FIG. 1 is a view schematically showing a conventional roller bearing, in which a rotating shaft is supported via a roller bearing inside a bearing housing implanted in a stator base (not shown). In the figure, reference numeral 1 denotes a substantially cylindrical bearing housing which is implanted in a central portion of a stator base (not shown), and a rotating shaft 2 is supported by a roller bearing 3 at a central opening of the housing. However, in order to incorporate the rotating shaft into the bearing housing via the roller bearing, the diameter of the roller bearing must be set to (the inner diameter of the bearing housing −
It cannot be assembled unless it is formed (with a play) smaller than half (rotation axis). Therefore, the diameter of the roller bearing is naturally limited to a thickness having a play.

[0003]

Therefore, when the conventional roller bearing is used for a small motor, when the small motor rotates at a high speed, the rotor inevitably causes the shaft runout and the surface runout due to the play of the bearing. Had a problem.

An object of the present invention is to provide a high-speed spindle motor in which a rotating shaft is supported by a bearing having no backlash for mounting a bearing, thereby suppressing shaft runout during high speed rotation.

[0005]

In order to solve the above-mentioned problems, a bearing housing is implanted in a central portion of a stator base, and a rotating shaft is provided inside the bearing housing. A spindle motor having a first row of rollers revolving on a track at a first distance from the rotation center, and a second row of rollers revolving on a track at a second distance from the rotation center. This can be achieved by supporting the rotating shaft. Further, as described in claim 2, the first group of rollers and the second group of rollers can be achieved by being positioned by a retainer made of resin. Further, as set forth in claim 3, it is possible to achieve this by setting the track at a first distance from the rotation center as the outer peripheral surface of the rotation shaft and the track at a second distance from the rotation center as the inner peripheral surface of the bearing housing.
Furthermore, a bearing housing is implanted in the center of the stator base, and a rotating shaft is provided inside the bearing housing, and the rotating shaft revolves on a track at a first distance from the center of rotation. In a method of manufacturing a spindle motor that is supported by a first-row roller group and a second-row roller group that revolves on a track at a second distance from the rotation center, a retainer and a rotation shaft are provided inside a bearing housing. This can be achieved by including a first step of loosely fitting and a second step of inserting a roller into the roller holding portion of the loosely fitted retainer.

[0006]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a sectional view showing a first embodiment of the present invention, and FIG. 2 is a sectional view taken along line CC of FIG. FIG.
FIG. 2 is an enlarged sectional view of a main part showing a retainer and rollers of FIG. 1. 1 to 3, reference numeral 4 denotes a stator base which is provided with a substantially cylindrical bearing housing 1 implanted in the center.
Reference numeral 5 denotes a stator core fixed to the bearing housing 1 by press fitting or the like, and reference numeral 6 denotes a coil wound around the stator core 5. Reference numeral 7 denotes a rotating shaft supported inside the bearing housing 1. Reference numeral 8 denotes an inverted deep dish type rotor case fixed to the outer periphery of the rotating shaft 7 by press fitting or the like. A permanent magnet is provided on the inner periphery of the rotor case. 14 are provided. The permanent magnet 14 may be a ring magnet, or may be divided into two parts or divided into n parts and fixed along the inner circumference. Reference numeral 9 denotes rollers in the first row. The roller group 9 in the first row rotates and revolves on a first orbit at a first distance from the center of rotation, that is, on an outer peripheral surface of the rotating shaft 7.
Reference numeral 10 denotes a second row of roller groups. The second row of roller groups 10 is on a second orbit at a second distance from the rotation center, that is,
The track on the inner peripheral surface of the bearing housing 1 rotates and revolves. Reference numeral 11 denotes a retainer that regulates a space between adjacent rollers of the first group of rollers 9, and also restricts this group of rollers from contacting the outer peripheral surface of the rotating shaft 7. In addition, the retainer 11 regulates the space between the adjacent rollers of the roller group 10 in the second row, and regulates the roller group to contact the inner peripheral surface of the bearing housing 4. That is, the retainer 11 has a first roller holding portion 11a for guiding the rollers to be on the first track, and a second roller holding portion 11b for guiding the rollers to be on the second track.
And (FIG. 2) In addition, the back surfaces 11C of the roller holding portions 11a and 11b for regulating the roller groups 9 and 10 of the retainer 11 to the outer peripheral surface of the rotating shaft 7 or the inner peripheral surface of the bearing housing 1 have an arcuate shape in the axial direction. It is formed (FIG. 3) to facilitate insertion at the time of roller insertion and to reduce frictional resistance at the time of rotation by pressing only near the center in the longitudinal direction of the roller groups 9 and 10. Reference numeral 12 denotes a washer for preventing the rollers inserted into the first roller holding portion 11a and the second roller holding portion 11b from coming out. Reference numeral 13 denotes a ball for smoothing the rotation of the retainer 11 in the bearing housing 1. The ball may be separately guided by a retainer, but may not be used without using a retainer, since the influence is not so great.

In the first embodiment, since the center of the stator core 5 and the center of the permanent magnet 14 are shifted by D, they are attracted by a magnetic force, and the rotor does not come off during rotation. The rotor is constituted by a rotor case 8 and a permanent magnet 14, and the stator is a bearing housing 1.
The stator core 5 in which the coil 6 is wound around the outer periphery of the rotor is fixed, but it is natural that a magnet may be placed on the stator side, the coil may be brought on the rotor side, and power may be supplied by a commutator. is there.

Next, FIG. 4 is a sectional view showing a second embodiment. In the figure, 15 is a bearing housing,
A retainer holding portion is provided near the bottom of the bearing housing 15 to support the lower portion of the retainer 11. Also in this embodiment, since the center of the stator core 5 and the center of the permanent magnet 14 are shifted by D, they are attracted by the magnetic force and the rotor does not come off during rotation.

Next, an assembling process of the high-speed spindle motor having such a structure will be described. A first step in which a bearing housing is implanted in the center of the stator base, while a rotor case is fixedly mounted on the rotating shaft and the retainer and the rotating shaft are loosely fitted inside the bearing housing; Subsequent to the first step, the second step is to insert a roller into the first roller holding portion 11a and the second roller holding portion 11b of the loosely fitted retainer to complete the second step.

[0010]

By assembling in such a process, the gap (play) required for inserting the roller bearing between the bearing housing and the rotating shaft is no longer required. Therefore, a high-speed spindle motor having no backlash between the bearing housing, the roller bearing, and the rotary shaft can be configured.
Therefore, the problem of the shaft runout and surface runout of the rotor, which has been inevitably caused by the play, is solved. Also, Retainer 1
Since the back surfaces 11C of the first roller holding portions 11a and 11b are formed in an arc shape in the axial direction, it is possible to easily insert the rollers and to reduce frictional resistance during rotation.

[Brief description of the drawings]

FIG. 1 is a sectional view of an essential part showing a first embodiment of the present invention;

FIG. 2 is a plan sectional view showing a bearing housing part of a section taken along line CC of FIG. 1;

FIG. 3 is an enlarged sectional view of a main part showing a retainer and rollers of FIG. 1;

FIG. 4 is a sectional view showing a second embodiment.

FIG. 5 is a sectional plan view showing a conventional roller bearing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 15 Bearing housing 2, 7 Rotating shaft 3 Roller bearing 4 Stator base 5 Stator core 6 Coil 8 Rotor case 9 Roller group in 1st row 10 Roller group in 2nd row 11 Retainer 12 Washer 14 Magnet

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3J101 AA13 AA33 AA42 AA52 AA62 AA72 BA11 FA01 FA15 FA46 GA24 5H605 BB05 BB15 BB19 CC02 CC04 DD09 EB10 EB16 GG04 5H621 BB07 GA01 JK08 JK13 JK19

Claims (4)

[Claims] 1. A first row in which a bearing housing is implanted in a central portion of a stator base and a rotary shaft is provided inside the bearing housing, and the orbit revolves on a track at a first distance from a rotation center. And a second row of rollers that revolves on a trajectory at a second distance from the center of rotation to support the rotating shaft. 2. The high-speed spindle motor according to claim 1, wherein the first group of rollers and the second group of rollers are positioned by a retainer made of resin. 3. The trajectory at a first distance from the rotation center is defined as an outer peripheral surface of the rotation shaft, and the trajectory at a second distance from the rotation center is defined as an inner peripheral surface of the bearing housing. Alternatively, the high-speed spindle motor according to claim 2. 4. A first row in which a bearing housing is implanted in a central portion of a stator base, a rotating shaft is provided inside the bearing housing, and the rotating shaft revolves on a track at a first distance from the center of rotation. In the method for manufacturing a spindle motor supported by a group of rollers and a group of rollers that revolves on a track at a second distance from the center of rotation, the retainer and the rotating shaft are loosely fitted inside the bearing housing. A method for manufacturing a high-speed spindle motor, comprising: a first step; and a second step of inserting a roller into a roller holding portion of a loosely fitted retainer.