JP2012189182A - Rolling bearing, bearing device, and information recording/reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rolling bearing that can restrain abnormal vibrations and load torque variations, a bearing device having the rolling bearing, and an information recording/reproducing device having the bearing device.SOLUTION: The rolling bearings 22A, 22B include inner rings 30A, 30B and outer rings 31A, 31B which are coaxially arranged, a plurality of rolling bodies 32A, 32B rotatably retained between the rolling surfaces 40A, 40B of the inner rings and the rolling surfaces 41A, 41B of the outer rings, and circular shield plates 33A, 33B which have outer peripheral parts fit to the outer rings and close circular spaces 34A, 34B formed between the outer rings and the inner rings. On at least one of the outer peripheral surface and rolling surface of the outer ring, a notch part 45 is so formed as to extend in the entire perimeter of each outer ring, and cut surfaces 46, 47 for forming the notch part are formed by being cut from one surface between the pressing points 62A, 62B wherein an outer peripheral part of the shield plate radially pushes the outer ring to the outside and the contact points 61A, 61B wherein the rolling bodies come into contact with the rolling surface of the outer ring.

Description

  The present invention relates to a rolling bearing with a shield plate, a bearing device including the rolling bearing, and an information recording / reproducing device including the bearing device.

  2. Description of the Related Art Conventionally, an information recording / reproducing apparatus such as a hard disk for recording and reproducing various kinds of information magnetically or optically on a disk is known. In general, this type of information recording / reproducing apparatus includes an actuator having a swing arm provided with a head portion at the tip thereof for recording / reproducing a signal on a disk. This actuator is rotatably supported by a bearing device provided on the base end side of the swing arm. In other words, the swing arm can be rotated along a horizontal plane by rotating the bearing device, and the signal can be recorded and reproduced by moving the head portion at the tip of the swing arm to a predetermined position of the disk. Is possible.

  By the way, the bearing device for rotating the swing arm is generally composed of a shaft, a sleeve, and a rolling bearing interposed between the shaft and the sleeve. In particular, rolling bearings used in this type of bearing device are required to operate stably over a long period of time.

  Therefore, conventionally, for example, a rolling bearing has been proposed in which an annular space defined between an outer ring and an inner ring is closed with a shield plate as shown in Patent Document 1 below. The shield plate described above is made of a metal plate formed in an annular shape, and is disposed at the end of the rolling bearing. The shield plate has an outer peripheral portion fitted to the outer ring and an inner peripheral portion separated from the inner ring, so that the shield plate is allowed in a state in which relative movement in the outer ring and the inner ring is allowed. It is installed.

  More specifically, a shield plate fitting portion (concave groove) having a shape in which an inner edge portion of the outer ring is cut out in a substantially L shape in cross section is formed at the end of the outer ring over the entire circumference. The inner peripheral wall surface of the shield plate fitting portion is formed in a tapered shape that is gradually expanded in diameter from the end surface of the outer ring toward the axial center. A plurality of obliquely bent protrusions are intermittently disposed in the circumferential direction on the outer edge of the shield plate. As a method of attaching the shield plate, first, the shield plate is pushed between the outer ring and the inner ring (annular space). At this time, the projections described above are slidably contacted with the inner peripheral wall surface of the shield plate fitting portion, so that the inner side of the shield plate fitting portion is bent and deformed from the connection portion with the outer edge of the annular portion of the shield plate. It will be inserted into. Then, when the shield plate is pushed to the back of the shield plate fitting portion, the above-described protrusion presses the inner peripheral wall surface of the shield plate fitting portion by the elastic restoring force and is hooked on the inner peripheral wall surface to be locked. Thereby, the outer peripheral part of a shield board is fitted by an outer ring | wheel, and a shield board is mounted | worn.

  According to the rolling bearing with the shield plate described above, it is possible to prevent dust from the outside from adhering to the rolling elements, the rolling surfaces of the outer ring and the inner ring, and internal lubricant leaks to the outside. It is possible to suppress this. Therefore, a rolling bearing with a shield plate is likely to operate stably over a long period of time compared with a bearing without a shield plate.

JP 2002-89574 A

  However, in the bearing device having the above-described conventional rolling bearing with a shield plate, when the shield plate is mounted, the inner peripheral wall surface of the shield plate fitting portion is strongly pressed by the projection protruding from the outer edge of the shield plate, There is a risk of unauthorized deformation such that a portion in the circumferential direction at the end of the outer ring bulges outward in the radial direction. In particular, in the sleeveless type bearing device in which the sleeve is omitted, there is nothing that restricts the outer ring from bulging outward in the radial direction. Thus, when the outer ring is deformed improperly, the roundness of the rolling surface of the outer ring is impaired, and problems such as abnormal vibration and load torque fluctuation occur.

  The present invention has been made in consideration of the above-described conventional problems, and an object thereof is to provide a rolling bearing, a bearing device, and an information recording / reproducing device capable of suppressing abnormal vibration and load torque fluctuation.

  A rolling bearing according to the present invention includes an inner ring and an outer ring arranged coaxially, and a rolling surface formed on the outer peripheral surface of the inner ring and a rolling surface formed on the inner peripheral surface of the outer ring. A plurality of rolling elements held in a freely rollable manner, and an annular shield plate having an outer peripheral portion fitted into the outer ring and closing an annular space defined between the inner ring and the outer ring. In the rolling bearing, at least one of the outer peripheral surface of the outer ring and the rolling surface of the outer ring is formed with a cutout portion extending over the entire outer ring, and cut from the one surface. A cutting surface rarely forming the notch, a pressing point where the outer peripheral portion of the shield plate presses the outer ring radially outward, and a contact point where the rolling element contacts the rolling surface of the outer ring, It is characterized by being located between.

Due to such features, the radially inner portion of the cut surface of the outer ring becomes thin, so that when the outer ring is pressed by the shield plate, the radially inner portion of the cut surface is positively deformed. By doing so, the pressing stress is released. As a result, the stress acting on the portion closer to the contact point than the notch is suppressed, and unauthorized deformation at the contact point portion with respect to the rolling elements of the rolling surface of the outer ring is suppressed.
The above-mentioned “pressing point” is not limited to a point, and when the outer peripheral portion of the shield plate is in line contact with the outer ring, it becomes a linear pressing point. It becomes a pressing point. In addition, the above-mentioned “contact point” is not limited to a point, and when the rolling element is in line contact with the rolling surface of the outer ring, it becomes a linear contact point, and when it is in surface contact, the surface shape This is the contact point.

  Further, in the rolling bearing according to the present invention, a shield plate fitting portion having a shape in which an inner edge portion of the end portion of the outer ring is cut out in a step shape is formed at the end portion of the outer ring over the entire circumference. It is preferable that the groove-shaped cutout portion extending along the circumferential direction of the outer ring is formed at a position outside the outer ring of the outer ring in the radial direction of the shield plate fitting portion.

  In such a rolling bearing, the outer peripheral surface of the outer ring is constricted by the groove-shaped notch, and the constricted portion is easily deformed. However, the groove-shaped notch is the diameter of the shield plate fitting portion. Since it is arranged at a position on the outer side in the direction, the thickness of the above-described constricted portion is reduced, and the constricted portion is particularly easily deformed. As a result, the pressing stress is reliably released, and unauthorized deformation at the contact point portion of the rolling surface of the outer ring is further suppressed.

  Further, the rolling bearing according to the present invention is the groove-shaped cutout portion extending along the circumferential direction of the outer ring at a position radially outside the rolling surface of the outer ring, of the outer circumferential surface of the outer ring. Is preferably formed.

  In such a rolling bearing, the outer peripheral surface of the outer ring is constricted by a groove-shaped notch, and the constricted portion is easily deformed. However, the groove-shaped notch is radially outside the rolling surface. Accordingly, the thickness of the constricted portion is reduced, and the constricted portion is particularly easily deformed. As a result, the pressing stress is reliably released, and unauthorized deformation at the contact point portion of the rolling surface of the outer ring is further suppressed.

  In the rolling bearing according to the present invention, it is preferable that the groove-shaped notch extending along the circumferential direction of the outer ring is formed on the rolling surface of the outer ring.

  As a result, the radially outer portion of the groove-shaped notch is easily deformed. However, since the groove-shaped notch is disposed on the rolling surface, the outer side of the notch is radially outer. The thickness of the portion is reduced, and the portion is particularly easily deformed. As a result, the pressing stress is reliably released, and unauthorized deformation at the contact point portion of the rolling surface of the outer ring is further suppressed.

  Further, in the rolling bearing according to the present invention, a shield plate fitting portion having a shape in which an inner edge portion of the end portion of the outer ring is cut out in a step shape is formed at the end portion of the outer ring over the entire circumference. Of the outer peripheral surface of the outer ring, the notch portion having a shape in which the outer edge portion of the end portion of the outer ring is cut out in a step shape is formed at a position radially outside the shield plate fitting portion. preferable.

  Thereby, the whole edge part of an outer ring becomes thin, and becomes easy to deform | transform especially. As a result, the pressing stress is reliably released, and unauthorized deformation at the contact point portion of the rolling surface of the outer ring is further suppressed.

  A bearing device according to the present invention includes the above-described rolling bearing and a shaft that is fitted inside the inner ring.

  Such a feature suppresses unauthorized deformation in the contact point portion of the outer ring rolling surface with respect to the rolling elements, thereby suppressing abnormal vibration and load torque fluctuation during the rotation operation.

  In addition, the bearing device according to the present invention preferably includes a sleeve that is fitted onto the outer ring.

  As a result, the pressing stress due to the shield plate is released to the sleeve, and unauthorized deformation of the outer ring radially outward is suppressed, so that abnormal vibration and load torque fluctuation during rotation operation can be suppressed, and the inner peripheral portion of the shield plate The gap between the inner ring and the inner ring is prevented from being widened, and the lubricant inside the rolling bearing can be prevented from leaking out.

  An information recording / reproducing apparatus according to the present invention includes the above-described bearing device, and an arm portion that is externally fitted to the outer ring and is rotatable about the axis of the shaft together with the outer ring, and supports the head gimbal assembly. A carriage, a rotation drive unit that rotates the magnetic recording medium, and an actuator that rotates the carriage and moves the head gimbal assembly in a direction parallel to the surface of the magnetic recording medium. It is a feature.

  According to this information recording / reproducing apparatus, since the bearing device that can suppress the unauthorized deformation at the contact point portion with respect to the rolling element of the rolling surface of the outer ring is provided, abnormal vibration and load torque fluctuation during the rotation operation are prevented. It is suppressed, and the operation accuracy of the carriage can be improved.

  An information recording / reproducing apparatus according to the present invention includes a bearing device having the above-described sleeve, and an arm that is externally fitted to the sleeve and is rotatable about the axis of the shaft together with the sleeve to support the head gimbal assembly. And a rotation drive unit that rotates the magnetic recording medium, and an actuator that rotates the carriage and moves the head gimbal assembly in a direction parallel to the surface of the magnetic recording medium. It may be a configuration.

  According to this information recording / reproducing apparatus, since the bearing device capable of suppressing the unauthorized deformation of the outer ring is provided, abnormal vibration and load torque fluctuation during rotation of the bearing device can be reliably suppressed, and the operation accuracy of the carriage can be improved. Further improvement can be achieved. In addition, since the bearing device described above can prevent the gap between the inner peripheral portion of the shield plate and the inner ring from widening and prevent the leakage of the lubricant, the amount of lubricant inside the rolling bearing can be reduced. Carriage malfunction due to decrease can be prevented, read / write error due to leaked lubricant adhering to magnetic recording medium can be prevented, and leaked lubricant adheres to the adhesive surface It is possible to prevent poor adhesion due to the operation.

  According to the rolling bearing, the bearing device, and the information recording / reproducing device according to the present invention, it is possible to prevent unauthorized deformation at the contact point portion with respect to the rolling element of the rolling surface of the outer ring. Load torque fluctuation can be suppressed.

1 is a perspective view showing an embodiment of an information recording / reproducing apparatus according to the present invention. It is a longitudinal section showing a pivot shaft which is an embodiment of a bearing device concerning the present invention. It is a top view of the 1st and 2nd rolling bearing which is 1st embodiment of the rolling bearing which concerns on this invention. It is sectional drawing between AA shown in FIG. It is sectional drawing which shows 1 process of the manufacturing method of the pivot axis | shaft shown in FIG. 2, and is a figure which shows the state which inserted the 2nd rolling bearing in the shaft. It is sectional drawing which shows 1 process of the manufacturing method of the pivot axis | shaft shown in FIG. 2, and is a figure which shows the state just before covering a sleeve. It is sectional drawing which shows 1 process of the manufacturing method of the pivot axis | shaft shown in FIG. 2, and is a figure which shows the state just before inserting a 1st rolling bearing in a shaft. It is sectional drawing which shows 1 process of the manufacturing method of the pivot axis | shaft shown in FIG. 2, and is a figure which shows the state which has provided the preload to the 1st rolling bearing and the 2nd rolling bearing. It is an expanded sectional view of the 1st rolling bearing in the state shown in FIG. It is an expanded sectional view of the 2nd rolling bearing in the state shown in FIG. It is a longitudinal cross-sectional view which shows the 1st, 2nd rolling bearing which is 2nd embodiment of the rolling bearing which concerns on this invention. It is a longitudinal cross-sectional view which shows the 1st, 2nd rolling bearing which is 3rd embodiment of the rolling bearing which concerns on this invention. It is a longitudinal cross-sectional view which shows the 1st and 2nd rolling bearing which is 4th embodiment of the rolling bearing which concerns on this invention. It is a longitudinal cross-sectional view which shows the 1st and 2nd rolling bearing which is a modification of the rolling bearing which concerns on this invention. It is a longitudinal cross-sectional view which shows the pivot shaft which is a modification of the bearing apparatus which concerns on this invention.

  Hereinafter, embodiments according to the present invention will be described with reference to the drawings. In the present embodiment, the case where the bearing device is used for the pivot shaft of the information recording / reproducing apparatus will be described.

(Information recording / reproducing device)
As shown in FIG. 1, an information recording / reproducing apparatus 1 of the present embodiment is an apparatus for writing on a disk (magnetic recording medium) D having a vertical recording layer by a vertical recording method. 2, a laser light source 4 that supplies a light beam from the base end side through the optical waveguide 3, a head gimbal assembly (HGA) 5 supported on the tip end side of the carriage 2, and the head gimbal assembly 5 on the disk surface (disc D Surface) Actuator 6 that scans and moves in a horizontal plane parallel to D1, a spindle motor (rotation drive unit) 7 that rotates disk D around a rotation axis L1 in a fixed direction, and a current modulated according to information in the head A control unit 8 that supplies the slider 5b of the gimbal assembly 5 and a housing 9 that houses these components therein are provided. To have.

The housing 9 has a box-like shape having a top opening made of a metal material such as aluminum, and has a rectangular bottom portion 9a as viewed from above, and a peripheral wall erected in the vertical direction with respect to the bottom portion 9a at the periphery of the bottom portion 9a. (Not shown). And the recessed part which accommodates each component mentioned above is formed in the inner side enclosed by the surrounding wall.
In FIG. 1, the peripheral wall surrounding the housing 9 is omitted for easy understanding.

  Further, a lid (not shown) is detachably fixed to the housing 9 so as to close the upper opening of the housing 9. The spindle motor 7 is attached to substantially the center of the bottom portion 9a, and the disc D is detachably fixed by fitting a center hole into the spindle motor 7.

The actuator 6 described above is attached to one corner of the bottom 9a outside the disk D. The actuator 6 is provided with a carriage 2 that can rotate around a rotation axis L2 in a horizontal plane around the pivot shaft 10.
The carriage 2 has an arm portion 2a extending from the base end portion toward the front end portion (in the direction of the disk D), and a base portion 2b supported in a cantilever manner via the arm portion 2a. It is integrally formed by processing or the like. The base 2b is formed in a substantially rectangular parallelepiped shape, and is supported so as to be rotatable around the pivot shaft 10. That is, the base portion 2 b is connected to the actuator 6 via the pivot shaft 10, and the pivot shaft 10 is the rotation center of the carriage 2.

The arm portion 2a extends in parallel to the surface direction (horizontal plane direction) of the upper surface of the base portion 2b on the side surface 2d opposite to the side surface 2c to which the actuator 6 is attached in the base portion 2b (side surface opposite to the corner portion). It has a flat plate shape and extends three along the height direction (vertical direction) of the base portion 2b.
Specifically, the arm portion 2a is formed in a tapered shape that tapers from the proximal end portion toward the distal end portion, and is arranged so that the disk D is sandwiched between the arm portions 2a. That is, the arm portion 2a and the disk D are configured to be alternately arranged, and the arm portion 2a can be moved in a direction parallel to the disk surface D1 (horizontal plane direction) by driving the actuator 6.
The carriage 2 and the head gimbal assembly 5 are retracted from the disk D by driving the actuator 6 when the rotation of the disk D is stopped.

The head gimbal assembly 5 is connected to the distal end of the arm portion 2a, and includes a suspension 5a and a slider 5b attached to the distal end of the suspension 5a.
Further, the head gimbal assembly 5 guides a light beam from the laser light source 4 to a slider 5b having a near-field light generating element (not shown) to generate near-field light, and uses the near-field light to generate various information on the disk D. Is recorded and reproduced.
Note that the near-field light generating element includes, for example, an optical minute aperture, a protrusion formed in a nanometer size, and the like.

(Bearing device)
Next, the configuration of the pivot shaft 10 as an embodiment of the bearing device according to the present invention will be described with reference to FIG.

As shown in FIG. 2, the pivot shaft 10 is a bearing device that pivotally supports the carriage 2 so as to be rotatable around the rotation axis L2. As a schematic configuration thereof, the pivot shaft 10 is erected on the bottom 9a of the housing 9 shown in FIG. A substantially cylindrical shaft 20, a sleeve 21 that is provided on the outer side in the radial direction of the shaft 20 and is disposed coaxially with the shaft 20 with the rotation axis L 2 as a common axis, and the shaft 20 and the sleeve 21. And first and second rolling bearings 22A and 22B interposed therebetween.
In the present embodiment, the direction along the rotation axis L2, that is, the axial direction is defined as the “axial direction”, the direction orthogonal to the rotation axis L2, that is, the radial direction is defined as the “radial direction”, and the circuit circulates around the rotation axis L2. The direction to perform is the “circumferential direction”. Further, one side in the axial direction (upper side in FIG. 2) is “upper”, and the other side, that is, the other side in the axial direction (lower side in FIG. 2) is “lower”.

  The shaft 20 is a shaft member that extends in the axial direction about the rotation axis L2. The shaft 20 includes a substantially cylindrical shaft core portion 20a, a flange portion 20b projecting radially outward from a lower end portion of the shaft core portion 20a, and a male screw portion 20c provided vertically on the lower end surface of the shaft core portion 20a. It is equipped with. The flange portion 20b is a ring-shaped flange portion in plan view formed on the outer periphery of the shaft core portion 20a, and the upper surface of the flange portion 20b is such that the inner peripheral portion is higher than the outer peripheral portion. It is formed in a step shape. The male screw portion 20c is a screwed portion having a male screw (not shown) formed on the outer peripheral surface. The male screw portion 20c is screwed into a female screw hole (not shown) formed in the bottom portion 9a (shown in FIG. 1) of the housing 9, so that the shaft 20 is erected on the bottom portion 9a of the housing 9. At this time, the shaft 20 is positioned in the height direction by the lower surface of the flange portion 20 b being in contact with the bottom portion 9 a of the housing 9.

The sleeve 21 is a substantially cylindrical member that is fitted around outer rings 31A and 31B of a first rolling bearing 22A and a second rolling bearing 22B, which will be described later, and the first rolling bearing 22A is located inside the upper end of the sleeve 21. And the second rolling bearing 22B is fitted inside the lower end of the sleeve 21. Further, the axial distance between the first rolling bearing 22A and the second rolling bearing 22B is set to a predetermined distance on the inner peripheral surface of the axially intermediate portion of the sleeve 21 (the portion between the upper and lower rolling bearings 22A and 22B). A spacer portion 21a to be held is formed. The spacer portion 21a is an annular convex portion projecting radially inward over the entire circumference, and outer rings 31A and 31B of first and second rolling bearings 22A and 22B, which will be described later, respectively. It is hanging. That is, the outer edge of the lower end portion of the outer ring 31A of the upper first rolling bearing 22A is hooked to the upper end surface of the spacer portion 21a, and the outer ring 31B of the lower second rolling bearing 22B is hooked to the lower end surface of the spacer portion 21a. The outer edge of the upper end is hooked.
The sleeve 21 is integrally assembled with the carriage 2 by being press-fitted or adhesively fitted inside a mounting hole (not shown) formed in the base 2b of the carriage 2 shown in FIG.

(First embodiment of rolling bearing)
Then, the structure of 22 A of 1st rolling bearings and 22B of 2nd rolling bearings which are 1st embodiment of the rolling bearing which concerns on this invention is demonstrated with reference to FIGS.

  As shown in FIG. 2, the first rolling bearing 22 </ b> A and the second rolling bearing 22 </ b> B are bearings with shield plates that are pivotally supported by the shaft 20, and are respectively mounted on the shaft 20 and spaced in the axial direction. It is installed. Further, the first rolling bearing 22A located on the upper side in the axial direction and the second rolling bearing 22B located on the lower side in the axial direction have the same configuration, and are arranged in directions that are vertically reversed.

  As shown in FIGS. 3 and 4, the schematic configuration of the first rolling bearing 22A (second rolling bearing 22B) is an inner ring 30A having an annular inner ring 30A (30B) in plan view and a rotation axis L2 as a common axis. An outer ring 31A (31B) disposed coaxially with (30B), and a plurality of rolling elements 32A (32B) that are rotatably held between the inner ring 30A (30B) and the outer ring 31A (31B), An annular shield plate 33A (33B) is provided between the inner ring 30A (30B) and the outer ring 31A (31B). The annular shield plate 33A (33B) closes the annular annular space 34A (34B) in plan view.

The inner ring 30A (30B) is a cylindrical cylindrical body that extends in the axial direction around the rotation axis L2, and is externally fitted to the shaft core portion 20a of the shaft 20 shown in FIG.
A curved groove-shaped rolling surface 40A (40B) into which a rolling element 32A (32B) is fitted so as to be capable of rolling is formed on the outer peripheral surface of the central portion in the axial direction of the inner ring 30A (30B). The rolling surface 40A (40B) is an arc-shaped groove portion extending in the circumferential direction along the vertical surface of the rotation axis L2, and extends over the entire circumference of the outer circumferential surface of the inner ring 30A (30B). It is installed.

  As shown in FIG. 2, the lower end surface of the inner ring 30B of the second rolling bearing 22B is in contact with the upper surface 20d of the flange portion 20b of the shaft 20 (the upper surface of the inner peripheral portion of the flange portion 20b). The lower end surface of the inner ring 30B of the two-rolling bearing 22B is locked by the flange portion 20b.

  As shown in FIGS. 3 and 4, the outer ring 31A (31B) is a cylindrical cylindrical body that surrounds the inner ring 30A (30B) and extends in the axial direction about the rotation axis L2, and the inner ring 30A ( 30B) and are provided around the outer side in the radial direction at intervals.

  A shield plate fitting portion 39A (for fitting the outer peripheral portion of the shield plate 33A (33B) to the outer end portion (end portion on the opening side of the sleeve 21 shown in FIG. 2) of the outer ring 31A (31B). 39B) is formed. More specifically, at the upper end portion of the outer ring 31A of the first rolling bearing 22A and the lower end portion of the outer ring 31B of the second rolling bearing 22B, the inner edge portion is cut out in a substantially L shape (stepped shape) in sectional view. The shield plate fitting portion 39A (39B) is formed over the entire circumference. The peripheral wall surface 39a (rising surface) of the shield plate fitting portion 39A (39B) is an undercut portion that locks a claw portion 36 of a shield plate 33A (33B) described later, from the end surface of the outer ring 31A (31B). It is formed in a tapered shape that is gradually expanded in diameter toward the center in the axial direction.

  Further, the rolling element 32A (32B) rolls at a position facing the rolling surface 40A (40B) of the inner ring 30A (30B) on the inner peripheral surface of the axially central portion of the outer ring 31A (31B). A curved groove-like rolling surface 41A (41B) is formed that can be fitted. The rolling surface 41A (41B) is an arc-shaped groove portion extending in the circumferential direction along the vertical surface of the rotation axis L2, and extends over the entire circumference of the inner circumferential surface of the outer ring 31A (31B). It is extended. Further, the rolling surface 41A (41B) of the outer ring 31A (31B) is formed in a shape obtained by inverting the rolling surface 40A (40B) of the inner ring 30A (30B) described above in a longitudinal sectional view.

  A groove-shaped notch 45 is formed over the entire outer peripheral surface of the outer end portion of the outer ring 31A (31B). More specifically, the notch 45 is a groove extending in the circumferential direction along the vertical surface of the rotation axis L2, and of the outer peripheral surface of the outer ring 31A (31B), the shield plate fitting portion 39A (39B). It is formed at a radially outer position. Further, the notch 45 is a groove having a V-shape in a longitudinal sectional view, and is formed by a pair of cut surfaces 46 and 47 cut obliquely from the outer peripheral surface of the outer ring 31A (31B). The axial positions of the pair of cut surfaces 46 and 47 are such that the outer peripheral portion of the shield plate 33A (33B) presses the outer ring 31A (31B) radially outward and the rolling element 32A (32B). Is in the range between the contact point 61A (61B) that contacts the rolling surface 41A (41B) of the outer ring 31A (31B), and the corner portion 48 formed by the pair of cut surfaces 46 and 47 is fitted with a shield plate It is at substantially the same axial position as the step surface 39b of the joint portion 39A (39B). The above-described pressing point 62A (62B) is a portion where the tip of a claw portion 36 described later comes into contact with the peripheral wall surface 39a of the shield plate fitting portion 39A (39B), and the step surface of the shield plate fitting portion 39A (39B) It is located on the outer end side than 39b. Further, the above-described contact point 62A (62B) is a contact point between the rolling element 32A (32B) and the rolling surface 41A (41B) of the outer ring 31A (31B) after applying a preload described later.

  As shown in FIG. 2, the lower end surface of the outer ring 31B of the second rolling bearing 22B is separated from the flange portion 20b of the shaft 20, and the lower end surface of the outer ring 31B of the second rolling bearing 22B is locked. Absent.

  The rolling element 32A (32B) is a sphere (ball), and is interposed between the rolling surface 40A (40B) of the inner ring 30A (30B) and the rolling surface 41A (41B) of the outer ring 31A (31B). These rolling surfaces 40A and 41A (40B and 41B) are sandwiched so as to be rotatable from both radial sides. The radius of this rolling element 32A (32B) is slightly smaller than the radius of curvature of the rolling section 40A, 41A (40B, 41B) in the longitudinal sectional view. In addition, a plurality of rolling elements 32A (32B) are arranged in parallel in the circumferential direction, and these rolling elements 32A (32B) are held so as to be rollable by a retainer (not shown). The number is 7 which is a prime number of 2 or more.

  As shown in FIG. 2, the shield plates 33A and 33B are closed in an annular shape in plan view that closes the annular spaces 34A and 34B from the outer end side (opening side of the sleeve 21) of the inner rings 30A and 30B and the outer rings 31A and 31B. This is a plate, and the outer peripheral portions of the shield plates 33A and 33B are fitted to the above-described shield plate fitting portions 39A and 39B, and are attached to the outer rings 31A and 31B. Further, the inner peripheral portions of the shield plates 33A and 33B are separated from the inner rings 30A and 30B, thereby allowing relative axial displacement between the inner rings 30A and 30B and the outer rings 31A and 31B.

  More specifically, as shown in FIGS. 3 and 4, the schematic configuration of the shield plate 33 </ b> A (33 </ b> B) includes an annular shield main body 35 formed in a plane perpendicular to the rotation axis L <b> 2, A plurality of claw portions 36 projecting from the outer peripheral edge of the shield main body 35.

  The outer peripheral portion 35a of the shield body 35 is stepped so as to protrude toward the annular space 34A (34B) over the entire circumference in order to increase the rigidity, and the bottom surface thereof is a shield plate fitting portion 39A. (39B) of the stepped surface 39b. Further, the inner diameter of the shield main body 35 is larger than the outer diameter of the inner ring 30A (30B), and a gap is formed across the entire circumference between the inner edge of the shield main body 35 and the inner ring 30A (30B).

The claw portion 36 is a protruding portion that obliquely protrudes radially outward from the outer peripheral edge portion of the shield main body 35, and is undercut fit to the tapered peripheral wall surface 39a of the shield plate fitting portion 39A (39B). Are combined. That is, the claw portion 36 has a distal end shield plate fitting portion 39A (39B) in a state in which the claw portion 36 is elastically bent and deformed radially inward from the connection portion with the outer peripheral edge portion of the shield body 35 as a base point. It is latched by the peripheral wall surface 39a. Thus, the claw portion 36 is locked to the peripheral wall surface 39a of the shield plate fitting portion 39A (39B), and the bottom surface of the outer peripheral portion 35a of the shield body 35 is the step surface 39b of the shield plate fitting portion 39A (39B). By being placed, the shield plate 33A (33B) is fitted to the outer ring 31A (31B). The shield plate 33A (33B) is intermittently provided with a plurality of claw portions 36 along the outer peripheral edge portion of the shield body 35, and the plurality of claw portions 36 are spaced in the circumferential direction in plan view. Are arranged evenly.
Note that the number of the claw portions 36 described above is five, and the number of the rolling elements 32 (seven) and the number of the claw portions 36 (five) are relatively prime.

  Incidentally, as shown in FIG. 2, the inner ring 30A of the first rolling bearing 22A and the inner ring 30B of the second rolling bearing 22B are arranged in the axial direction along the axial direction of the shaft 20 (arrow side shown in FIG. 2). Preload is applied, and as a result, the axial center 40a of the rolling surface 40A of the inner ring 30A of the first rolling bearing 22A and the axial central portion 40b of the rolling surface 40B of the inner ring 30B of the second rolling bearing 22B, The axial interval T1 of the first rolling bearing 22A is the axial center 41a of the rolling surface 41A of the outer ring 31A of the first rolling bearing 22A and the axial center 41b of the rolling surface 41B of the outer ring 31B of the second rolling bearing 22B. It is smaller than the interval T2 in the direction.

  At this time, the contact point 60A between the rolling contact surface 40A of the inner ring 30A of the first rolling bearing 22A and the rolling element 32A is more than the axial center portion 40a of the rolling contact surface 40A of the inner ring 30A of the first rolling bearing 22A. The contact point 60B between the rolling surface 40B of the inner ring 30B of the second rolling bearing 22B and the rolling element 32B is located on the upper side (outer end side), and the rolling surface 40B of the inner ring 30B of the second rolling bearing 22B. It is located on the lower side (outer end side) than the axial central portion 40b. Further, the contact point 61A between the rolling surface 41A of the outer ring 31A of the first rolling bearing 22A and the rolling element 32A is lower than the axial center portion 41a of the rolling surface 41A of the outer ring 31A of the first rolling bearing 22A ( The sleeve 21 is positioned in the axial direction center end direction, that is, in the direction of the inner end portion on the opposite side of the outer end portion, and is in contact with the rolling surface 41B of the outer ring 31B of the second rolling bearing 22B. The contact point 61B with the moving body 32B is located above (inner end side) the axial center portion 41b of the rolling surface 41B of the outer ring 31B of the second rolling bearing 22B.

(Pivot shaft manufacturing method)
Next, a method for manufacturing the pivot shaft 10 configured as described above will be described with reference to FIGS.
First, as shown in FIG. 5, an adhesive (not shown) (for example, anaerobic adhesive) (not shown) is applied to the outer peripheral surface of the lower end portion of the shaft core portion 20 a of the shaft 20. Then, the second rolling bearing 22B is inserted through the shaft core portion 20a of the shaft 20, and the second rolling bearing 22B is pushed in until the lower end surface of the inner ring 30B comes into contact with the upper surface 20d of the flange portion 20b.

  Next, as shown in FIG. 6, after applying an adhesive (not shown) to the inner peripheral surfaces of the upper end portion and the lower end portion of the sleeve 21, the sleeve 21 is inserted through the shaft core portion 20 a of the shaft 20, and the spacer portion The sleeve 21 is pushed in until the lower end surface of 21a contacts the upper end surface of the outer ring 31B of the second rolling bearing 22B.

  Next, as shown in FIG. 7, the first rolling bearing 22 </ b> A is inserted into the shaft core portion 20 a of the shaft 20, and the annular space defined between the shaft core portion 20 a of the shaft 20 and the sleeve 21 is inserted. The first rolling bearing 22A is inserted into the outer ring 31A until the lower end surface of the outer ring 31A contacts the upper end surface of the spacer portion 21a.

Next, a preload is applied in the axial direction to the first rolling bearing 22A and the second rolling bearing 22B.
That is, as shown in FIG. 8, the first rolling bearing 22A and the second rolling bearing 22B are pressed against the shaft 20 and the sleeve while pressing the inner ring 30A of the first rolling bearing 22A toward the second rolling bearing 22B with a predetermined pressure. 21 is fixed.
A pressing jig J is used to press the inner ring 30A of the first rolling bearing 22A with a predetermined pressure. The pressing jig J is a pusher having a tip formed on a flat surface, and the tip can be reliably and stably brought into contact with the upper end surface of the inner ring 30A of the first rolling bearing 22A.

  As described above, when the inner ring 30A is pressed by the pressing jig J, as shown in FIG. 9, the rolling surface 40A of the inner ring 30A and the rolling element 32A of the first rolling bearing 22A are in the axial direction of the rolling surface 40A. Point contact is made on the pressing jig J side (upper side) from the central portion 40a (contact point 60A). Further, the rolling contact surface 41A of the outer ring 31A and the rolling element 32A make point contact on the second rolling bearing 22B side (lower side) with respect to the axial center portion 41a of the rolling contact surface 41A (contact point 61A). Therefore, the preload direction is the arrow direction shown in FIG.

On the other hand, since the inner ring 30B of the second rolling bearing 22B is pressed from the flange portion 20b side, as shown in FIG. 10, the rolling surface 40B of the inner ring 30B of the second rolling bearing 22B and the rolling element 32B are Point contact is made on the flange portion 20b side (lower side) with respect to the axial center portion 40b of the rolling surface 40B (contact point 60B). Further, the rolling contact surface 41B of the outer ring 31B and the rolling element 32B make point contact on the first rolling bearing 22A side (upper side) with respect to the axial center portion 41b of the rolling contact surface 41B (contact point 61B). Therefore, the preload direction is the arrow direction shown in FIG.
Thus, preload is applied to the first rolling bearing 22A and the second rolling bearing 22B, and the pivot shaft 10 is completed.

  According to the first rolling bearing 22A and the second rolling bearing 22B described above, the radially inner portions (corner portions 48) of the pair of cut surfaces 46, 47 of the outer rings 31A, 31B are thinned so that the outer ring 31A, The outer peripheral surface of 31B becomes a constricted shape. Since the constricted portion (corner portion 48) is easily deformed, when the outer rings 31A and 31B are pressed by the shield plates 33A and 33B, the above-described corner portion 48 is positively deformed to release the pressing stress. As a result, the stress acting on the contact points 61A and 61B side of the notch 45 is suppressed, and unauthorized deformation of the rolling surfaces 41A and 41B of the outer rings 31A and 31B is suppressed. Therefore, abnormal vibrations and load torque fluctuations during the rotation operation of the carriage 2 can be suppressed.

  In particular, in the first rolling bearing 22A and the second rolling bearing 22B described above, the groove-shaped notch 45 is formed at a position radially outside the shield plate fitting portions 39A and 39B on the outer peripheral surfaces of the outer rings 31A and 31B. Since it is formed, the thickness of the above-described constricted portion (corner portion 48) is reduced, and the constricted portion is easily deformed. Accordingly, the pressing stress is reliably released, and the unauthorized deformation of the rolling surfaces 41A and 41B of the outer rings 31A and 31B is reliably suppressed.

  Therefore, according to the information recording / reproducing apparatus 1 including the pivot shaft 10 having the first rolling bearing 22A and the second rolling bearing 22B described above, abnormal vibration and load torque fluctuation during the rotation operation of the carriage 2 can be suppressed. 2 can be improved.

(Second embodiment of bearing device)
Next, a first rolling bearing 122A and a second rolling bearing 122B, which are the second embodiment of the rolling bearing according to the present invention, will be described with reference to FIG.
In addition, the same code | symbol is attached | subjected about the structure similar to 22 A of 1st rolling bearings of the above-mentioned 1st embodiment, and the 2nd rolling bearing 22B, and description is abbreviate | omitted.

  As shown in FIG. 11, the first rolling bearing 122A (second rolling bearing 122B) is located on the outer peripheral surface of the outer ring 31A (31B) on the outer side in the radial direction of the rolling surface 41A (41B) of the outer ring 31A (31B). At the position, a groove-shaped notch 145 is formed over the entire circumference. The notch 145 is a groove extending in the circumferential direction along the vertical plane of the rotation axis L2, and is vertically cut by a pair of cut surfaces 146, 147 cut obliquely from the outer peripheral surface of the outer ring 31A (31B). It is formed in a V shape when viewed from the top.

  According to the first rolling bearing 122A and the second rolling bearing 122B described above, the groove-shaped notch 145 is disposed at the radially outer position of the rolling surface 41A (41B). The thickness of the portion (the portion on the inner side in the radial direction of the notch portion 145) that is confined by the thickness decreases, and the constricted portion is easily deformed. Accordingly, the pressing stress is surely released, and unauthorized deformation in the contact point 61A (61B) portion of the rolling surface 41A (41B) of the outer ring 31A (31B) is reliably suppressed.

(Third embodiment of bearing device)
Next, a first rolling bearing 222A and a second rolling bearing 222B, which are a third embodiment of the rolling bearing according to the present invention, will be described with reference to FIG.
In addition, the same code | symbol is attached | subjected about the structure similar to 22 A of 1st rolling bearings of the above-mentioned 1st embodiment, and the 2nd rolling bearing 22B, and description is abbreviate | omitted.

  As shown in FIG. 12, the first rolling bearing 222A (second rolling bearing 222B) has an annular rolling surface at the position of the axial center portion of the rolling surface 41A (41B) of the outer ring 31A (31B). A groove-shaped notch 245 extending along 41A (41B) is formed over the entire circumference. The notches 245 are grooves extending in the circumferential direction along the vertical plane of the rotation axis L2, and a pair of cut surfaces cut obliquely from the rolling surface 41 (41B) of the outer ring 31A (31B). 246 and 247 are formed in a V shape in a longitudinal sectional view.

  According to the first rolling bearing 222A and the second rolling bearing 222B described above, since the groove-shaped notch 245 is disposed on the rolling surface 41A (41B), the portion that is confined by the notch 245 (the notch). The thickness of the part 245 in the radial direction of the notch 245 is reduced, and the constricted part is easily deformed. Accordingly, the pressing stress is surely released, and unauthorized deformation in the contact point 61A (61B) portion of the rolling surface 41A (41B) of the outer ring 31A (31B) is reliably suppressed.

(Fourth embodiment of bearing device)
Next, a first rolling bearing 322A and a second rolling bearing 322B, which are a fourth embodiment of the rolling bearing according to the present invention, will be described with reference to FIG.
In addition, the same code | symbol is attached | subjected about the structure similar to 22 A of 1st rolling bearings of the above-mentioned 1st embodiment, and the 2nd rolling bearing 22B, and description is abbreviate | omitted.

  As shown in FIG. 13, the first rolling bearing 322A (second rolling bearing 322B) is disposed on the outer peripheral surface of the outer ring 31A (31B) at a position radially outside the shield plate fitting portion 39A (39B). A cutout portion 345 having a shape in which the outer edge portion of the outer end portion of 31A (31B) is cut out in a stepped shape is formed over the entire circumference. More specifically, the notch 345 has a substantially L-shaped cross-sectional view formed on the outer peripheral surface of the upper end portion of the outer ring 31A of the first rolling bearing 322A and the outer peripheral surface of the lower end portion of the outer ring 31B of the second rolling bearing 322B. It is a step part. The peripheral wall surface 346 (rising surface) of the notch 345 is a wall surface cut from the end surface on the outer end side of the outer ring 31A (31B) toward the axial center, and extends along the axial direction. Has been. Further, the step surface 347 (cut surface) of the notch 345 is a wall surface cut along the vertical surface of the rotation axis L2 from the outer peripheral surface of the outer ring 31A (31B) toward the radially inner side, and the shield plate It is substantially in the same axial position as the step surface 39b of the fitting portion 39A (39B).

  According to the first rolling bearing 322A and the second rolling bearing 322B described above, since the stepped notch 345 is formed on the outer edge of the outer end portion of the outer ring 31A (31B) over the entire circumference, the outer ring 31A ( The thickness of the entire outer end portion 31B) is reduced, and the outer end portion is easily deformed. Accordingly, the pressing stress is reliably released, and unauthorized deformation of the rolling surface 41A (41B) of the outer ring 31A (31B) is reliably suppressed.

As described above, the embodiments of the rolling bearing, the bearing device, and the information recording / reproducing device according to the present invention have been described. However, the present invention is not limited to the above-described embodiment, and may be changed as appropriate without departing from the scope of the present invention. Is possible.
For example, in the above-described embodiment, the case where the bearing device is applied to the pivot shaft 10 of the information recording / reproducing apparatus having near-field light has been described as an example. The present invention can be applied to a bearing device and a rotating shaft portion of various devices.

  In the first to third embodiments described above, the groove-shaped notches 45, 145, and 245 are formed in a V shape in a longitudinal sectional view, but the present invention is a cross-section of the groove-shaped notch. The view shape can be appropriately modified, and may be, for example, a cutout portion 445 having a right triangle shape in cross section as shown in FIG. 14 (a), or a circular arc in cross section as shown in FIG. 14 (b). The shape may be a cutout 545, or may be a cutout 645 having a quadrangular sectional shape as shown in FIG.

  In the first to fourth embodiments described above, the spacer portion 21a is formed on the inner peripheral surface of the sleeve 21, but the present invention accommodates a spacer member separate from the sleeve inside the sleeve, and It is also possible to adopt a configuration in which it is interposed between 31A and 31B. Furthermore, the spacer can be omitted by using an outer ring having a longer axial dimension than the inner ring and abutting the end faces of the outer ring.

  In the first to fourth embodiments described above, the sleeve-type pivot shaft 10 (bearing device) having the sleeve 21 is described. However, in the present invention, the sleeve 21 as shown in FIG. 15 is omitted. It is particularly suitable for the sleeveless type bearing device 110. In the sleeveless type bearing device 110, the outer rings 131A and 131B are directly attached to an attachment hole or the like, and the outer rings 131A and 131B are placed inside an attachment hole (not shown) formed in the base 2b of the carriage 2 shown in FIG. May be an information recording / reproducing apparatus in which the bearing device is integrally combined with the carriage 2 by being press-fitted or adhesively fitted. The sleeveless type bearing device includes a spacer member 50 interposed between the outer rings 131A and 131B. The outer rings 131A and 131B are thicker than the sleeve type outer rings 31A and 31B. Yes, thicker than the inner rings 30A, 30B.

  In the first embodiment described above, the pivot shaft 10 having two rolling bearings (the first rolling bearing 22A and the second rolling bearing 22B) has been described. However, the present invention includes three or more rolling bearings. For example, a configuration in which a third rolling bearing is disposed between the first rolling bearing 22A and the second rolling bearing 22B may be used.

  In the first to fourth embodiments described above, one shield plate 33A, 31B is attached to one rolling bearing 22A-322A, 22B-322B, and between the outer rings 31A, 31B and the inner rings 30A, 30B. The annular spaces 34A and 34B defined in the above are closed on one side in the axial direction, but the shield plates are positioned so as to be positioned on both sides of the rolling elements 32A and 32B with respect to one rolling bearing 22A to 322A and 22B to 322B. A configuration may be adopted in which two 33A and 33B are mounted and both sides of the annular spaces 34A and 34B in the axial direction are closed.

  Moreover, although the number of the claw portions 36 of the shield plates 33A and 33B is five, the number is not limited to this number and may be set freely. However, it is preferable to use a prime number of 3 or more from the viewpoint of being able to be arranged without facing the radial direction across the rotation axis L2 and easily contributing to the roundness of the outer rings 31A and 31B.

The rolling elements 32A and 32B are balls. However, the rolling elements are not limited to balls, and any rolling elements such as rollers may be used. And although the number of rolling elements 32A, 32B in one rolling bearing 22A, 22B is seven, it is not limited to this number and may be set freely.
However, it is preferable that the number of the claw portions 36 and the number of the rolling elements 32A and 32B are combined so that they have a relatively prime relationship. For example, as described above, not only a combination of prime numbers such that the number of claw portions 36 is 5 and the number of rolling elements 32A and 32B is 7, but the number of claw portions 36 is 5 and the number of rolling elements 32A and 32B. Can be a combination of a prime number and an odd number such that the number of nail portions 36 is 9, and a combination of odd numbers such that the number of rolling elements 32A and 32B is 25 is also possible. Combinations of odd and even numbers in which the number of 36 is 9 and the number of rolling elements 32A and 32B is 16 are also possible.

Further, the shield plate fitting portions 39A and 39B may not be formed in an annular shape over the entire circumference of the inner rings 30A and 30B, and may be formed in a plurality at intervals along the circumferential direction. In this case, after the shield plates 33A and 33B are attached to the inner rings 30A and 30B, there is an advantage that the shield plates 33A and 33B can easily be restricted from rotating in the circumferential direction with respect to the inner rings 30A and 30B.
However, since the shield plates 33A and 33B can be attached to the inner rings 30A and 30B without worrying about the relative circumferential relationship between the inner rings 30A and 30B and the shield plates 33A and 33B, the shield plate fitting portion 39A and 39B are preferably formed in an annular shape.

  In addition, it is possible to appropriately replace the constituent elements in the above-described embodiments with known constituent elements without departing from the gist of the present invention, and the above-described first to fourth embodiments may be appropriately combined. In addition, modifications may be combined as appropriate.

DESCRIPTION OF SYMBOLS 1 ... Information recording / reproducing apparatus 2 ... Carriage 2a ... Arm part 5 ... Head gimbal assembly 6 ... Actuator 7 ... Spindle motor (rotation drive part)
10 ... Pivot shaft (bearing device)
20 ... Shaft 21 ... Sleeve 22A ... First rolling bearing (rolling bearing)
22B ... Second rolling bearing (rolling bearing)
30A ... Inner ring 30B ... Inner ring 31A ... Outer ring 31B ... Outer ring 32A ... Rolling body 32B ... Rolling body 33A ... Shield plate 33B ... Shield plate 34A ... Annular space 34B ... Annular space 39A ... Shield plate fitting portion 39B ... Shield plate fitting portion 41A ... rolling surface 41B ... rolling surface 45 ... notch 46 ... cut surface 47 ... cut surface 61A ... contact point 61B ... contact point 62A ... pressure point 62B ... pressure point 110 ... bearing device 131A ... outer ring 131B ... outer ring 122A ... first rolling bearing 122B ... second rolling bearing 145 ... notch 146 ... notch surface 147 ... notch surface 222A ... first rolling bearing 222B ... second rolling bearing 245 ... notch part 246 ... notch surface 247 ... notch surface 322A ... first rolling bearing 322B ... second rolling bearing 345 ... notch 347 ... step surface (cut surface)
445 ... notch 545 ... notch 645 ... notch D ... disk (magnetic recording medium)

Claims (9)

An inner ring and an outer ring arranged on the same axis;
A plurality of rolling elements that are movably held between a rolling surface formed on the outer peripheral surface of the inner ring and a rolling surface formed on the inner peripheral surface of the outer ring;
An annular shield plate having an outer peripheral portion fitted into the outer ring and closing an annular space defined between the inner ring and the outer ring;
In a rolling bearing equipped with
At least one of the outer peripheral surface of the outer ring and the rolling surface of the outer ring is formed with a notch extending over the entire outer ring,
A cut surface that is cut from the one surface to form the cutout portion is a pressing point at which the outer peripheral portion of the shield plate presses the outer ring radially outward, and the rolling element is a rolling surface of the outer ring. A rolling bearing characterized by being located between the contact point and the contact point. The rolling bearing according to claim 1,
At the end of the outer ring, a shield plate fitting portion having a shape in which the inner edge portion of the end of the outer ring is cut out in a stepped shape is formed over the entire circumference,
The groove-shaped notch extending along the circumferential direction of the outer ring is formed in the outer circumferential surface of the outer ring at a radially outer position of the shield plate fitting portion. Rolling bearing. In the rolling bearing according to claim 1 or 2,
The groove-shaped notch extending along the circumferential direction of the outer ring is formed at a position radially outside the rolling surface of the outer ring, of the outer circumferential surface of the outer ring. Rolling bearing. In the rolling bearing according to any one of claims 1 to 3,
A rolling bearing characterized in that a groove-shaped notch extending along a circumferential direction of the outer ring is formed on a rolling surface of the outer ring. In the rolling bearing according to any one of claims 1 to 4,
At the end of the outer ring, a shield plate fitting portion having a shape in which the inner edge portion of the end of the outer ring is cut out in a stepped shape is formed over the entire circumference,
Of the outer peripheral surface of the outer ring, the notch portion having a shape in which the outer edge portion of the end portion of the outer ring is notched in a step shape is formed at a position radially outside the shield plate fitting portion. Characteristic rolling bearing.   A bearing device comprising: the rolling bearing according to any one of claims 1 to 5; and a shaft inserted into the inner ring. The bearing device according to claim 6,
A bearing device comprising a sleeve fitted on the outer ring. A bearing device according to claim 6,
A carriage that is externally fitted to the outer ring and is rotatable about the axis of the shaft together with the outer ring, and has an arm portion that supports a head gimbal assembly;
A rotation drive for rotating the magnetic recording medium;
An actuator for rotating the carriage and moving the head gimbal assembly in a direction parallel to the surface of the magnetic recording medium;
An information recording / reproducing apparatus comprising: A bearing device according to claim 7,
A carriage that is externally fitted to the sleeve and is rotatable about the axis of the shaft together with the sleeve, and has an arm portion that supports the head gimbal assembly;
A rotation drive for rotating the magnetic recording medium;
An actuator for rotating the carriage and moving the head gimbal assembly in a direction parallel to the surface of the magnetic recording medium;
An information recording / reproducing apparatus comprising:

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