JP6354464B2 - Bearing device - Google Patents

Description

  The present invention relates to a bearing device.

  8A to 8C show an example of a schematic configuration of a hard disk drive {Hard Disc Drive (hereinafter also referred to as HDD)}. The HDD includes a magnetic disk (hard disk) 2 for recording information (data), a spindle motor 4 for rotating the magnetic disk 2, a swing arm 8 as an actuator having a magnetic head 6 attached to the tip, and a swing arm. 8 and a voice coil 9 that rotationally drives the swing arm 8.

  The swing arm 8 is rotatably supported on the base Bs of the HDD via the bearing device 10, and when the swing arm 8 is rotationally driven by the voice coil 9, the magnetic head 6 is attached to the rotating magnetic disk 2. Translate (trace). Thereby, in the HDD, information can be read from the magnetic disk 2 via the magnetic head 6 or information can be written (recorded) to the magnetic disk 2.

  The bearing device 10 includes a central shaft 12 erected on the base Bs of the HDD, and a pair of ball bearings 14 and 16 fixed to the outer periphery of the central shaft 12. A sleeve 18 on which the swing arm 8 is externally mounted is fixed to the outer periphery of the pair of ball bearings 14 and 16. As described above, the pair of ball bearings 14, 16 enables relative rotation between the central shaft 12 and the sleeve 18.

  The pair of ball bearings 14 and 16 are a plurality of bearing rings that are rotatably arranged between the inner rings 14a and 16a and the outer rings 14b and 16b as a pair of bearing rings arranged to face each other so as to be relatively rotatable. Balls 14c and 16c as rolling elements, and retainers 14d and 16d for holding the balls 14c and 16c one by one rotatably. Between the inner rings 14a and 16a and the outer rings 14b and 16b, a pair of non-contact type shields 14e and 16e are interposed as sealing members for sealing the inside of the bearing. This prevents intrusion of foreign matter (for example, dust) from the outside of the bearing and prevents leakage of the grease composition sealed inside the bearing to the outside of the bearing.

  The ball bearings 14 and 16 are attached to the sleeve 18 and the sleeve 18 in a state where the inner rings 14 a and 16 a are fitted on the center shaft 12 and the outer rings 14 b and 16 b are fitted on the sleeve 18. The swing arm 8 is pivotally supported so as to be rotatable and swingable. Therefore, the sleeve 18 and the swing arm 8 constitute a swing member that swings around the central axis 12.

  An annular spacer 20 is fitted to the inner peripheral portion of the sleeve 18 so as to be interposed between the pair of ball bearings 14 and 16. As a result, the ball bearings 14 and 16 are positioned and fixed at a predetermined position with a predetermined preload applied, and can stably rotate and swing without rattling, and the swing arm 8 can be smoothly moved with good responsiveness. Can be rotated.

  Here, as pointed out in Patent Document 1, when the swing angle of the swing arm 8 is repeatedly swung within a relatively small range, the grease in the swung range is thinned by the balls 14c and 16c that pass repeatedly, A phenomenon occurs in which the scraped portion is moved toward the folded portion. When the swing arm 8 swings within a relatively small range and then swings beyond the range, the balls 14c and 16c exceed the grease piles formed so far. A large resistance is generated against the rotational force. Therefore, the bearing rotational torque is likely to fluctuate, and there is a risk of fretting wear due to poor lubrication.

  Therefore, in the invention described in Patent Document 1, a mechanism in which a ball is relatively less rotated in a specific direction than in other directions at a portion where the ball of the bearing contacts, more specifically, a spring in a cage. By providing the plate, the above-described problems are solved.

JP 2006-179104 A

  However, in the invention described in Patent Document 1, since it is necessary to strongly press the ball with a spring plate provided in the cage, there is a problem that the torque becomes heavy and unstable, and the control to follow a narrow recording track cannot be performed. there were.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a bearing device capable of preventing the formation of a crest of grease and preventing fretting wear while suppressing an increase in torque.

The above object of the present invention can be achieved by the following constitution.
(1) a shaft member;
Two or more ball bearings fixed to the outer periphery of the shaft member;
A bearing device comprising:
Each of the two or more ball bearings includes an inner ring fixed to the outer periphery of the shaft member, an outer ring disposed radially outside the inner ring, and a plurality of balls disposed between the inner ring and the outer ring. With
A swing member that swings around the shaft member is fixed to the outer periphery of the two or more ball bearings,
The bearing device, wherein the inner ring or the outer ring is inclined in a direction in which a radial load applied to two or more ball bearings changes when the swinging member swings.
(2) The shaft member or the swing member has a protruding portion that protrudes in a radial direction and abuts against an axial side surface of the inner ring or the outer ring,
The projecting portion is formed with a convex portion or a concave portion capable of adjusting the inclination of the inner ring or the outer ring, The bearing device according to (1).
(3) Between the inner ring or the outer ring adjacent in the axial direction, a spacer that contacts the axial side surface of the inner ring or the outer ring is disposed.
The bearing device according to (1) or (2), wherein the spacer is capable of adjusting an inclination of the inner ring or the outer ring by changing an axial width in a direction in which the radial load changes. .
(4) Between the inner ring or the outer ring adjacent in the axial direction, a plate that is in contact with a part of the axial side surface of the inner ring or the outer ring and that can adjust the inclination of the inner ring or the outer ring is disposed. The bearing device according to any one of (1) to (3), wherein:
(5) The ball bearing is incorporated in the shaft member and the swinging member while a preload is applied,
(1) to (4), wherein the inclination of the inner ring or the outer ring can be adjusted by shifting the center of gravity of the preload load from the center of the ball bearing in a direction in which the radial load changes. The bearing apparatus as described in any one of these.
(6) The bearing device according to any one of (1) to (5), wherein the bearing device is marked so that a direction in which the inner ring or the outer ring is inclined can be identified.
(7) The diameter of the ball is Da,
When the pitch circle radius of the balls is dm,
The inclination angle of the inner ring or the outer ring is set in a range of 0.009 × Da ^0.5 / dm ^{0.6 to} 0.0015 × Da ^0.5 / dm ^0.6 (radian). The bearing device according to any one of (1) to (6).
(8) The diameter of the ball is Da,
When the pitch circle radius of the balls is dm,
The inclination angle of the inner ring or the outer ring is set in a range of 0.003 × Da ^0.5 / dm ^{0.6 to} 0.006 × Da ^0.5 / dm ^0.6 (radian). The bearing device according to any one of (1) to (6).
(9) A pair of the ball bearings are provided,
The inclination direction of the inner ring or the outer ring of one of the ball bearings and the inclination direction of the inner ring or the outer ring of the other ball bearing are opposite directions (1) to (8) The bearing apparatus as described in any one.
(10) The bearing device according to any one of (1) to (9), wherein the swing member includes a swing arm of a hard disk drive.

  According to the bearing device of the present invention, the inner ring or the outer ring is inclined in a direction in which the radial load applied to the plurality of ball bearings changes when the swing member swings. The relative contact positions of the raceways of the inner ring and the outer ring and the balls are shifted in the rotation direction. Therefore, the crest of grease does not increase, the torque is stabilized, and fretting wear can be prevented. Moreover, in the present invention, while having a simple configuration in which the inner ring or the outer ring is tilted, the above-described remarkable effects are exhibited. And in this invention, since the spring plate which restrains a ball | bowl is not provided in a holder | retainer like the prior art, the problem that torque becomes heavy and becomes unstable does not arise.

It is sectional drawing of the bearing apparatus which concerns on 1st Embodiment. FIG. 2 is an enlarged view around a portion A in FIG. 1. It is sectional drawing of the bearing apparatus which concerns on 2nd Embodiment. It is sectional drawing of the bearing apparatus which concerns on 3rd Embodiment. It is sectional drawing of the bearing apparatus which concerns on 4th Embodiment. It is a graph which shows the relationship between the inclination of an inner ring | wheel or an outer ring | wheel, and the number of seeks to a torque fluctuation | variation. It is sectional drawing which shows the modification of a convex part. (A) is a schematic sectional view showing the entire configuration of the HDD, (b) is a plan view showing the entire configuration of the HDD, and (c) is a half sectional view showing a conventional bearing device.

  Hereinafter, a bearing device according to an embodiment of the present invention will be described with reference to the drawings.

(First embodiment)
As shown in FIG. 1, the bearing device 10 </ b> A of the present embodiment has the same schematic configuration as the bearing device 10 shown in FIGS. Therefore, the description is omitted or simplified. Further, the bearing device 10A of the present embodiment is used for the purpose of pivoting and swinging the HDD swing arm 8 as shown in FIGS. 8A to 8C. For example, a high-speed oscillating rotating part such as a head part of a chip mounter or a part that oscillates within a narrow range by a servo motor or the like may be used for axial support.

  The bearing device 10 </ b> A includes a center shaft 12 as a shaft member having a center O and extending in the axial direction, and a pair of ball bearings 14 and 16 fixed to the outer periphery of the center shaft 12. A sleeve 18 on which the swing arm 8 is externally mounted is fixed to the outer periphery of the pair of ball bearings 14 and 16. As described above, the pair of ball bearings 14, 16 enables relative rotation between the central shaft 12 and the sleeve 18. The central shaft 12 has a cylindrical shape with a screw hole 13 passing through the center, and is fixed to a base Bs of the HDD or the like by a screw (not shown) that is screwed into the screw hole 13.

  The pair of ball bearings 14 and 16 are a plurality of bearing rings that are rotatably arranged between the inner rings 14a and 16a and the outer rings 14b and 16b as a pair of bearing rings arranged to face each other so as to be relatively rotatable. Balls 14c and 16c as rolling elements, and retainers 14d and 16d that hold the balls 14c and 16c one by one rotatably. The ball bearings 14 and 16 of this embodiment are not provided with the shields 14e and 16e as in the bearing device 10 of FIG. 8C, but similar shields may be provided. The pair of ball bearings 14 and 16 are assembled and fixed between the central shaft 12 and the sleeve 18 by a bonding or press-fitting method while a preload is applied.

  The ball bearings 14 and 16 are attached to the sleeve 18 and the sleeve 18 in a state where the inner rings 14 a and 16 a are fitted on the center shaft 12 and the outer rings 14 b and 16 b are fitted on the sleeve 18. A swing arm 8 (see FIGS. 8A to 8B) is pivotally supported so as to be rotatable and swingable. Therefore, the sleeve 18 and the swing arm 8 constitute a swing member that swings around the central axis 12 (center O). The sleeve 18 is not necessarily provided, and the swing arm 8 may be directly fitted on the outer rings 14b and 16b. Even when the bearing device 10A is used for purposes other than the purpose of pivotally supporting the swing arm 8 of the HDD, swing members are fixed to the outer circumferences of the outer rings 14b and 16b.

  The sleeve 18 is formed with a protruding portion 18a that protrudes radially inward (center O side) and contacts the axial side surfaces 14f and 16f of the adjacent outer rings 14b and 16b. The protrusions 18a appropriately position the relative positions of the outer rings 14b and 16b and the sleeve 18 in the axial direction.

  A protruding portion 12 a that protrudes radially outward is formed at the axial end of the central shaft 12. The protruding portion 12a is in contact with the axial side surface 16g of the inner ring 16a and is connected to the wide portion 12b extending to the outside in the radial direction from the inner ring 16a and the wide portion 12b, and the outer ring 16b and the sleeve 18 are interposed through a gap. And a narrow portion 12c opposed to each other, and has a substantially stepped cross section as a whole.

  When the bearing device 10 </ b> A configured in this way is applied to an application for supporting the HDD swing arm 8, a radial load is applied to the pair of ball bearings 14, 16 when the swing arm 8 swings. This radial load changes so as to synchronize with the swing of the swing arm 8, and the change direction F is relative to the direction connecting the swing arm 8 and the voice coil 9 as shown in FIG. Vertical direction.

  In the bearing device 10A, the inner rings 14a and 16a or the outer rings 14b and 16b of the ball bearings 14 and 16 are tilted in the radial load change direction F. More specifically, in the virtual plane parallel to the radial load change direction F as shown in FIG. 1, the inner ring moves toward the circumferential direction R connecting the radial load change direction F and the axial direction (direction in which the center O extends). 14a, 16a or outer rings 14b, 16b are inclined.

  In the present embodiment, in the pair of ball bearings 14 and 16, the inner rings 14a and 16a are inclined in the radial load change direction F, and the outer rings 14b and 16b are not inclined.

  When the ball bearing 14 on the upper side in the figure is assembled into the central shaft 12 and the sleeve 18 while being applied with a preload, the center of gravity of the preload is shifted from the center O of the ball bearing 14 to one side F1 in the radial load changing direction F. It is shifted. Thereby, since a slight fitting gap is provided, the inner ring 14a is inclined in the radial load change direction F. At this time, the contact angle α4 on the one side F1 in the radial load change direction F of the ball bearing 14 is larger than the contact angle α3 on the other side F2 (α4> α3).

  Further, a part of the portion of the wide portion 12b that contacts the side surface 16g in the axial direction of the inner ring 16a is more specifically a part of the other side F2 in the radial load changing direction F (indicated by symbol A in the figure). As shown in FIG. 2, the portion) is provided with a convex portion 19 capable of adjusting the inclination of the inner ring 16a. The convex part 19 of this embodiment consists of a pair of convex piece 19a, 19b spaced apart to radial direction. The pair of convex pieces 19a, 19b is formed by providing an indentation 19c between them. The inner ring 16 a is tilted in the radial load change direction F by the convex portion 19. At this time, the contact angle α1 on the one side F1 in the radial load change direction F of the ball bearing 16 is smaller than the contact angle α2 on the other side F2 (α1 <α2).

  Here, when the ball bearings 14 and 16 are rotated, the ball 14c on the one having a larger contact angle, that is, on the one side F1 in the radial load changing direction F if the ball bearing 14 is on the other side F2 on the other side F2. The rotation speed of 16c increases. For this reason, when the central shaft 12 or the sleeve 18 swings in the rotational direction, a slight difference occurs in the rolling length of the balls 14c and 16c between the one side F1 and the other side F2, and the ball having the larger contact angle The rolling lengths of 14c and 16c are slightly increased.

  Further, when the radial load changes so as to synchronize with the swing, the contact pressure between the balls 14c and 16c on the side receiving the load and the inner rings 14a and 16a and the outer rings 14b and 16b increases, and the balls 14c and 16c on the opposite side increase. The contact pressure between the inner ring 14a, 16a and the outer ring 14b, 16b is reduced. For this reason, the whole balls 14c and 16c are pulled in the ball rolling range with higher surface pressure.

  Therefore, when the swinging is repeated, the relative contact positions of the balls 14c and 16c with the inner rings 14a and 16a and the outer rings 14b and 16b are shifted in the rotation direction with time. Therefore, the crest of grease does not increase, the torque is stabilized, and fretting wear is prevented. Further, in the present invention, the above-described remarkable effects can be achieved with a simple configuration in which the inner rings 14a and 16a or the outer rings 14b and 16b are inclined. And in this invention, since the spring plate which restrains a ball | bowl is not provided in a holder | retainer like the prior art, the problem that torque becomes heavy and becomes unstable does not arise.

  Note that the bearing device 10A in which the inner rings 14a and 16a or the outer rings 14b and 16b are tilted needs to be fixed to the HDD or the like so that the tilted direction coincides with the radial load change direction F. Therefore, the bearing device 10A is marked at a position having a certain relationship with the tilted direction so that the tilted direction of the inner rings 14a, 16a or the outer rings 14b, 16b can be identified. The marking method is not particularly limited, and for example, an arrow may be indicated in a tilted direction, or a protrusion or a groove may be provided in the tilted direction. Further, marking may be performed in a direction perpendicular to the tilted direction, and the marking may be aligned and incorporated in the direction in which the swing arm 8 and the voice coil 9 are connected. When the central shaft 12 is fixed to the base Bs of the HDD, a projection or the like may be provided on the lower surface of the central shaft 12 so that the tilted direction and the radial load changing direction F may be matched.

  Further, when a screw thread is formed on the base Bs and the central shaft 12 of the HDD and the bearing device 10 and the swing arm 8 are fixed to the base Bs by screwing each other, the central shaft with respect to the base Bs. 12 is defined by the phase relationship between the base Bs and the thread of the central shaft 12. Therefore, the inclination directions of the inner rings 14a, 16a or the outer rings 14b, 16b coincide with the radial load change direction F, that is, the direction perpendicular to the direction connecting the swing arm 8 and the voice coil 9 while being fixed to the base Bs. As described above, it is preferable to process the threads of the base Bs and the central shaft 12 and adjust their phases in advance. By adjusting the thread phase in this way, it is possible to perform a reliable operation without being aware of the directionality during assembly, and the work efficiency can be improved.

(Second Embodiment)
FIG. 3 shows a bearing device 10A according to the second embodiment. In the present embodiment, in the pair of ball bearings 14 and 16, the outer rings 14b and 16b are inclined in the radial load change direction F, and the inner rings 14a and 16a are not inclined.

  The protruding portion 18a of the sleeve 18 is formed on a part of the portion in contact with the axial side surface 14f of the outer ring 14b on the upper side in the figure, more specifically on a part of one side F1 in the radial load changing direction F (in the figure, A convex portion (not shown because it is a minute convex portion) capable of adjusting the inclination of the outer ring 14b is provided on the portion indicated by the symbol B). As the shape of the convex portion, for example, the same shape as the convex portion 19 (see FIG. 2) of the first embodiment is employed. The outer ring 14b is tilted in the radial load change direction F by this convex portion. At this time, the contact angle α4 on the one side F1 in the radial load change direction F of the ball bearing 14 is larger than the contact angle α3 on the other side F2 (α4> α3).

  Further, the protruding portion 18a of the sleeve 18 is a part of the portion in contact with the axial side surface 16f of the lower outer ring 16b in the drawing, more specifically, a part of the other side F2 in the radial load changing direction F ( In the drawing, a convex portion (not shown because it is a minute convex portion) capable of adjusting the inclination of the outer ring 16b is provided in a portion indicated by a symbol C). As the shape of the convex portion, for example, the same shape as the convex portion 19 (see FIG. 2) of the first embodiment is employed. The outer ring 16b is tilted in the radial load change direction F by this convex portion. At this time, the contact angle α1 on the one side F1 in the radial load change direction F of the ball bearing 16 is smaller than the contact angle α2 on the other side F2 (α1 <α2).

  Thus, even when the outer rings 14b and 16b are tilted in the radial load change direction F, the same effects as those of the above-described embodiment can be obtained.

(Third embodiment)
FIG. 4 shows a bearing device 10A according to the third embodiment. This embodiment is the same as the second embodiment in that the outer rings 14b and 16b are tilted in the radial load change direction F, and the inner rings 14a and 16a are not tilted, but the outer ring 16b below the drawing is tilted. The difference is that the direction is reversed.

  That is, in the present embodiment, the protruding portion 18a of the sleeve 18 is partly part of the portion in contact with the axial side surface 16f of the lower outer ring 16b in the figure, more specifically, one side in the radial load changing direction F. A convex portion (not shown because it is a minute convex portion) capable of adjusting the inclination of the outer ring 16b is provided in a part of F1 (the portion indicated by reference sign D in the drawing). As the shape of the convex portion, for example, the same shape as the convex portion 19 (see FIG. 2) of the first embodiment is employed. The outer ring 16b is tilted in the radial load change direction F by this convex portion. At this time, the contact angle α1 on the one side F1 in the radial load change direction F of the ball bearing 16 is larger than the contact angle α2 on the other side F2 (α1> α2).

  In this way, when the radial direction is received by receiving the radial load by making the inclination direction of the outer ring 14b of one ball bearing 14 and the inclination direction of the outer ring 16b of the other ball bearing 16 opposite (symmetrical direction), It can suppress that it vibrates to an axial direction by the difference in rigidity of each part. Further, the inclination of the sleeve 18 with respect to the center axis 12 (center O) can also be reduced.

  Even when the inner rings 14a and 16a are inclined as in the first embodiment, the inclination direction of the inner ring 14a of one ball bearing 14 and the inclination direction of the inner ring 16a of the other ball bearing 16 are reversed. The direction (symmetrical direction) is desirable.

(Fourth embodiment)
FIG. 5 shows a bearing device 10A according to the fourth embodiment. In this embodiment, the outer rings 14b and 16b are tilted in the radial load change direction F, and the inner rings 14a and 16a are the same as in the third embodiment in that they are not tilted. However, a method of tilting the outer rings 14b and 16b is used. Different.

  The sleeve 18 of the present embodiment is not provided with the protruding portion 18a. Instead of the projecting portion 18a, a substantially annular spacer 20 is disposed between the outer rings 14b and 16b adjacent in the axial direction so as to come into contact with the axial side surfaces 14f and 16f of the outer rings 14b and 16b.

  The spacer 20 is configured to have different axial widths in the radial load change direction F. That is, the spacer 20 is set so that the axial width L1 of the one side F1 in the radial load change direction F is larger than the axial width L2 of the other side F2.

  By this spacer 20, the outer rings 14b and 16b are inclined in the radial load changing direction F. At this time, the contact angle α4 on the one side F1 in the radial load change direction F of the ball bearing 14 is larger than the contact angle α3 on the other side F2 (α4> α3), and the contact angle on the one side F1 of the ball bearing 16 is increased. α1 is larger than the contact angle α2 on the other side F2 (α1> α2).

  Even when configured in this way, it is possible to achieve the same effects as those of the third embodiment.

  A substantially annular spacer that abuts against the axial side surfaces 14g and 16g of the inner rings 14a and 16a is disposed between the inner rings 14a and 16a adjacent in the axial direction, and the axial width of the spacer is changed by changing the radial load. The inner rings 14a and 16a may be tilted by making them different in the direction F.

(Fifth embodiment)
In addition, between the inner rings 14a, 16a or the outer rings 14b, 16b adjacent in the axial direction, a part of the axial side faces 14g, 16g of the inner rings 14a, 16a or the axial side faces 14f, 16f of the outer rings 14b, 16b are in contact. A metal arcuate plate (not shown) that can adjust the inclination of the inner rings 14a, 16a or the outer rings 14b, 16b may be arranged.

  The arcuate plate is, for example, disposed between the inner rings 14a, 16a or the outer rings 14b, 16b only on one side F1 in the radial load changing direction F, and the axial side surfaces 14g, 16g or the outer rings 14b, 16b of the inner rings 14a, 16a. It is configured not to be disposed between the inner rings 14a, 16a or the outer rings 14b, 16b on the other side F2 in the radial load changing direction F. Also with this configuration, α4> α3 and α1> α2 can be satisfied, and therefore the same effects as those of the fourth embodiment can be achieved.

(Example)
Next, the bearing device 10A is incorporated in the HDD, and a test is conducted as to how the torque fluctuation is affected when the inclination of the inner ring 14a, 16a or the outer ring 14b, 16b in the radial load change direction F is changed. went.

  FIG. 6 shows the torque fluctuation when a constant seek is performed with the swing angle of the swing arm 8 being 0.5 degrees in the bearing device 10A having an inner diameter of 5 mm, and the swing arm 8 is periodically swung larger than 0.5 degrees. FIG. 9 is a graph showing the number of seeks when the current value fluctuations observed by the current value fluctuations of the voice coil 9 and exceeding the initial 200% are shown. The horizontal axis in FIG. 6 indicates the inclination of the inner rings 14a, 16a or the outer rings 14b, 16b with respect to the central axis 12, and the vertical axis indicates the number of seeks when the current value changes.

  In the range indicated by the cross, the current value fluctuation did not exceed 200% of the initial value even after 100 million seeks, and was below the judgment level. In the range indicated by the rhombus marks, the current value fluctuation exceeded 200% of the initial value after 1 million seeks to 100 million seeks. When this bearing race surface was observed, no abnormality was found. In the range indicated by the triangle mark, the current value fluctuation exceeded 200% of the initial value after 10,000 to 100 million seeks. When this bearing race surface was observed, wear was observed.

  Thus, if the tilt angle is too large, the contact surface pressure between the balls 14c and 16c and the raceways of the inner rings 14a and 16a and the outer rings 14b and 16b increases in part, shortening the service life and increasing the loss torque. Become. If the tilt angle is too small, the effect of shifting the relative contact positions of the balls 14c, 16c with the inner rings 14a, 16a and the outer rings 14b, 16b in the rotational direction due to swinging will be reduced. The effect of reducing the formation of the peaks is reduced, and there is a possibility that a reading error occurs in the HDD.

Therefore, the inclination of the inner ring 14a, 16a or the outer ring 14b, 16b in the radial load change direction F is set to 0.009 × Da ^0.5 / dm ^{0.6 to} 0.0015 × Da ^0.5 / dm ^0.6 ( It is preferable to set in the range of radians. Da is the diameter of the balls 14c and 16c, and dm is the pitch circle radius of the balls 14c and 16c. By setting the inclination in this manner, the relative contact position between the balls 14c and 16c and the inner rings 14a and 16a and the outer rings 14b and 16b is rotated in the rotational direction within a range in which the loss torque does not increase and the life is not problematic. The effect which shifts to is obtained.

Therefore, the inclination of the inner ring 14a, 16a or the outer ring 14b, 16b in the radial load change direction F is set to 0.003 × Da ^0.5 / dm ^{0.6 to} 0.006 × Da ^0.5 / dm ^0.6 ( By setting in the range of radians), there is almost no effect on the loss torque, and the effect that the relative contact positions of the balls 14c, 16c with the inner rings 14a, 16a and the outer rings 14b, 16b are shifted in the rotational direction by swinging. Can be obtained sufficiently.

  In addition, this invention is not limited to embodiment mentioned above, A change, improvement, etc. are possible suitably.

  The number of ball bearings constituting the bearing device 10A is not particularly limited as long as it is two or more, and an arbitrary plurality of ball bearings may be provided.

  In the above-described embodiment, the protrusions 12a and 18a of the central shaft 12 and the sleeve 18 are provided with convex portions that can adjust the inclination of the inner rings 14a and 16a or the outer rings 14b and 16b. May be provided. Further, the convex portion is not necessarily formed integrally with the protruding portions 12a and 18a, and may be a separate member. FIG. 7 shows an example in which a convex portion is formed by fixing the thin plate 22 to the wide portion 12b of the protruding portion 12a by adhesion or the like.

2 Magnetic disk 4 Spindle motor 6 Magnetic head 8 Swing arm (swing member)
9 Voice coil 10, 10A Bearing device 12 Center shaft (shaft member)
12a Protruding part 12b Wide part 12c Narrow part 13 Screw hole 14, 16 Ball bearings 14a, 16a Inner ring 14b, 16b Outer ring 14c, 16c Ball 14d, 16d Cage 14e, 16e Shield 14f, 16f Axial side face 14g, 16g Axial direction Side 18 Sleeve (Oscillating member)
18a Protrusion 19 Protrusion 19a, 19b Protrusion 19c Indentation 20 Spacer 22
Bs base O center

Claims (10)

A shaft member;
Two or more ball bearings fixed to the outer periphery of the shaft member;
A bearing device comprising:
Each of the two or more ball bearings includes an inner ring fixed to the outer periphery of the shaft member, an outer ring disposed radially outside the inner ring, and a plurality of balls disposed between the inner ring and the outer ring. With
A swing member that swings around the shaft member is fixed to the outer periphery of the two or more ball bearings,
The bearing device, wherein the inner ring or the outer ring is inclined in a direction in which a radial load applied to two or more ball bearings changes when the swinging member swings. The shaft member or the swing member has a protruding portion that protrudes in a radial direction and abuts against an axial side surface of the inner ring or the outer ring,
2. The bearing device according to claim 1, wherein the protruding portion is formed with a convex portion or a concave portion capable of adjusting an inclination of the inner ring or the outer ring. Between the inner ring or the outer ring adjacent in the axial direction, a spacer that contacts the axial side surface of the inner ring or the outer ring is disposed,
3. The bearing device according to claim 1, wherein the spacer is capable of adjusting an inclination of the inner ring or the outer ring by changing an axial width in a direction in which the radial load changes. Between the inner ring or the outer ring adjacent in the axial direction, a plate that is in contact with a part of the axial side surface of the inner ring or the outer ring and that can adjust the inclination of the inner ring or the outer ring is disposed. The bearing device according to any one of claims 1 to 3, wherein The ball bearing is incorporated into the shaft member and the swing member while being applied with a preload,
5. The inclination of the inner ring or the outer ring can be adjusted by shifting the center of gravity of the preload load from the center of the ball bearing in a direction in which the radial load changes. The bearing device according to claim 1. The bearing device according to claim 1, wherein the bearing device is marked so that a direction in which the inner ring or the outer ring is inclined can be identified. The diameter of the ball is Da,
When the pitch circle radius of the balls is dm,
The inclination angle of the inner ring or the outer ring is set in a range of 0.009 × Da ^0.5 / dm ^{0.6 to} 0.0015 × Da ^0.5 / dm ^0.6 (radian). The bearing apparatus of any one of Claims 1-6. The diameter of the ball is Da,
When the pitch circle radius of the balls is dm,
The inclination angle of the inner ring or the outer ring is set in a range of 0.003 × Da ^0.5 / dm ^{0.6 to} 0.006 × Da ^0.5 / dm ^0.6 (radian). The bearing apparatus of any one of Claims 1-6. A pair of the ball bearings are provided,
The tilt direction of the inner ring or the outer ring of one of the ball bearings and the tilt direction of the inner ring or the outer ring of the other ball bearing are opposite directions. 2. A bearing device according to item 1. The bearing device according to claim 1, wherein the swing member includes a swing arm of a hard disk drive.

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