JP2005207455A - Pivot bearing device of bearing device hdd and assembling method for bearing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To allow easy setting of the preload even if four ball bearings are set in and enhance the resistance against shock. <P>SOLUTION: A bearing device according to this invention is structured so that four ball bearings 1, 2, 3, 4 are installed on a shaft 8 and a preload is applied in the axial direction, wherein two or more bearings have such a structured that the widths L1 and L2 of the inner ring and outer ring differ. Therein a spacer 19 is installed between the inner rings 1b and 2b of two bearings 1 and 2 confronting each other on the inside in the axial direction, and at least either of the outer rings 1a and 2a constituting the ball bearings 1 and 2 located inside. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a magnetic disk device (HDD: Hard Disk).
The present invention relates to a bearing device used for a pivot portion that rotatably supports a read / write head of a disk memory device such as a drive).

Conventionally, for example, in the case of a 3.5-inch magnetic disk device, two ball bearings incorporated between a fixed shaft and a housing are used with a preload applied.
In recent years, magnetic disk devices have become increasingly denser and faster accessible. For this reason, the pivot bearing device is also strongly required to have high rigidity and low torque without increasing the outer diameter.
Therefore, it is conceivable to increase the number of bearings. For large angular contact ball bearings and the like, there is a method of adjusting the differential width and pre-loading four rows in combination, but it is very difficult to adjust the differential width with a small diameter miniature bearing.

Conventionally, there is a prior art related to a bearing device that incorporates two ball bearings in which the inner ring width dimension (axial width dimension) is narrower than the outer ring width dimension (axial width dimension) in order to eliminate the outer ring spacer. It is known (see Patent Document 1).
JP 10-318255 A

However, according to the technique disclosed in Patent Document 1, the outer ring spacer can be eliminated,
The demand for higher rigidity could not be met.
The present invention has been made in view of such problems of the prior art, and an object of the present invention is to easily set a preload and to achieve high rigidity while incorporating four ball bearings.

In a first invention for achieving the above object, in a bearing device in which four ball bearings are incorporated in a shaft and preloaded in the axial direction, a difference is provided in the width dimension between the inner ring and the outer ring of two or more bearings. It is in the point made into the bearing device characterized by this.
According to the present invention, it is not necessary to adjust the difference width, and a preload can be applied to each.

According to a second aspect of the present invention, in the first aspect of the invention, the width of the ball bearing incorporated in the axially inner side is narrower than the width of the ball bearing incorporated outside.
According to the present invention, since the width of the bearing incorporated inside is smaller than that of the bearing incorporated outside, the position of the ball of the inner bearing can be arranged on both outsides and the moment rigidity can be increased compared to incorporating the same width bearing. Can do.

According to a third invention, in the first or second invention described above, a spacer is provided between inner rings of two ball bearings facing each other on the inner side in the axial direction, and the inner ball bearings of the two are configured. The bearing device is characterized in that at least one of the outer rings is not abutted.
According to the present invention, the preload setting can be easily performed without adjusting the width between the spacer inserted into the inner ring and the outer ring of the housing and the difference width between the bearings.

According to a fourth invention, in any one of the first to third inventions, a bearing device is characterized in that the width of the inner ring is narrower than the width of the outer ring.
According to the present invention, since the inner ring is narrower than the outer ring, preload setting is facilitated in the direction in which the inner rings of the bearings arranged on both outer sides are pushed inward, and the outer rings of the bearings arranged on both outer sides are arranged inward. Rather than preloading in the pushing direction, the moment stiffness can be increased.

According to a fifth aspect of the present invention, in any of the first to fourth aspects of the present invention, the ball bearing incorporated inside does not include a sealing plate.
According to the present invention, since the bearing sealing plate incorporated inside is eliminated, the bearing width dimension can be reduced, and the overall width dimension of the apparatus can be reduced.
According to the present invention, since the bearing incorporated in the inner side does not include a sealing plate, the width of the bearing can be reduced, and the position of the ball of the inner bearing can be arranged on both outer sides than incorporating the bearing of the same width. Can be bigger.

According to a sixth invention, in any one of the first to fifth inventions, each ball bearing is characterized in that each raceway groove is offset from a central position in the axial direction of each of the inner ring and the outer ring. This is in the point that the bearing device is used.
According to the present invention, by providing a sealing plate in both outer directions by offsetting, a bearing having a narrow width can be formed, and each width can be narrower than a bearing not offset. For this reason, each ball can be arrange | positioned on both outer sides rather than the bearing apparatus incorporating a wide bearing, and moment rigidity can be enlarged.

According to a seventh invention, in any one of the first to sixth inventions, two ball bearings to be incorporated on the inner side are preliminarily applied and fixed, and then the ball bearings to be incorporated on both outer sides are applied with a preload and fixed. The bearing device is characterized by the above.
According to the present invention, the O-type preload can be performed by the inner two rows of bearings, and the O-type preload can also be performed by the outer bearing, so that the moment rigidity can be increased as compared with the case where either one is the X-type preload. .

According to an eighth aspect of the present invention, there is provided an HDD pivot bearing device including the bearing device according to any one of the first to seventh aspects of the invention.
According to the present invention, since the bearing device has high rigidity, the head can be moved at a high speed and the position can be reliably controlled to a required position, and the data access speed of the HDD is improved.

According to a ninth aspect of the invention, there is provided a method for assembling the bearing device according to any one of claims 1 to 6, wherein the ball bearings are first fixed with two preloaded ball bearings and then assembled on both outer sides. The ball bearing is preassembled with a preload, and the bearing device is assembled.
According to the present invention, the O-type preload can be performed with the inner two rows of bearings, and the O-type preload can also be performed with the outer bearings. Therefore, the moment rigidity can be increased as compared with the case where either one is the X-type preload. .

  According to the present invention, in a bearing device in which four ball bearings are incorporated and preloaded in the axial direction, there is a difference in the width dimension between the inner ring and the outer ring of two or more bearings. Since the preload can be applied to each of them without necessity, the manufacture of the bearing becomes easy.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
In addition, this embodiment is only one embodiment of the present invention, and is not construed as being limited thereto. The design can be changed within the scope of the present invention.
In this embodiment, a swing bearing pivot bearing device of a magnetic disk device will be described as an example. In addition, according to the present embodiment, a useful effect can be obtained for improving the rigidity of 3.5 inches or less used for server HDDs that require high-speed access in particular.

  FIG. 1 shows a pivot bearing device for a swing arm of a magnetic disk device according to the present embodiment, which includes a shaft (fixed shaft) 8, a housing 9, and four rolling ball bearings incorporated between the shaft 8 and the housing 9. 1, 2, 3, 4, and shows a state where four bearings are preloaded and fixed. A swing arm (not shown) is provided on the outer periphery of the apparatus.

  Each rolling ball bearing 1 (2, 3, 4) includes an outer ring 1a (2a, 3a, 4a), an inner ring 1b (2b, 3b, 4b), and a cage 6 between the outer inner rings 1a, 1b. A plurality of rolling elements (balls) 5 to be incorporated and a sealing plate 7 disposed between the outer and inner rings 1a and 1b.

  In this embodiment, the two opposing bearings 1 and 2 incorporated inside the shaft 8 are configured such that the width dimension L1 of the inner rings 1b and 2b is narrower than the width dimension L2 of the outer rings 1a and 2a, respectively. Yes. Further, the outer rings 1 a and 2 a of the respective bearings 1 and 2 incorporated inside the abutting end surfaces 1 c and 2 c abut against the end surfaces 11 and 12 of the step portion 10 of the housing 9.

Further, the two bearings 3, 4 incorporated outside the respective inner bearings 1, 2 have the same width of the outer rings 3a, 4a and the inner rings 3b, 4b (the inner ring width dimension L1 and the outer ring The width dimension L2 is the same).
The outer bearings 3 and 4 have their bearing outer ring end faces 3c and 4c in contact with the end faces 1d and 2d of the inner bearing outer rings 1a and 2a.
Further, the inner rings 1b, 2b of the inner bearings 1, 2 have both end faces 1e, 1f, 2e, 2f, the stepped end faces 11, 12 of the housing 9, and the inner ring end faces 3d, 4d of the outer bearings 3, 4. Not touching. In other words, the inner rings 1b, 2b, 3b, 4b are pushed in with a preload, but the gaps S1, S2, S3, S4 are vacant because the inner inner rings 1b, 2b are narrow.
The respective bearing width dimensions are not particularly limited, but it goes without saying that the object of the present invention is achieved.

  In this embodiment, rolling elements are provided in the raceway grooves d provided in the outer ring 1a (2a, 3a, 4a) and the inner ring 1b (2b, 3b, 4b) constituting each bearing 1 (2, 3, 4). , But each track groove d is provided at the center position in the width direction of the outer ring 1a (2a, 3a, 4a) and the inner ring 1b (2b, 3b, 4b).

  Further, in this embodiment, sealing plates (shields) 7 are provided on both sides of each bearing 1 (2, 3, 4). The sealing plate 7 is not limited to the shield of the shape shown in the figure, and may be a shield of another shape, or may be a non-contact seal or a contact seal, and the design can be changed within the scope of the present invention. It is.

  In addition, as a pivot bearing apparatus, a seal ring may be further fixed to both sides, and a magnetic body seal may be used.

FIG. 2A shows a state in which the two inner bearings 1 and 2 are opposed to each other and incorporated between the shaft 8 and the housing 9 to set the preload.
In the figure, reference numerals 15 and 16 denote an upper preload jig and a lower preload jig for the inner bearings 1 and 2, respectively, and the lower preload jig 16 has a role of relative positioning between the shaft 8 and the housing 9.
The inner rings 1b and 2b can be fixed by press-fitting while observing the resonance frequency, or can be fixed by adhesion while applying a load such as a weight or a spring.

  FIG. 2B shows an example in which two outer bearings 3 and 4 are opposed to each other and assembled between the shaft 8 and the housing 9 and fixed while applying a preload. In this case, since the inner bearing inner rings 1b, 2b fixed earlier are narrower than the outer rings 1a, 2a, the outer bearing outer rings 3a, 4a are directly applied to the inner bearing outer rings 1a, 2a to set the preload. It is possible. In the figure, 17 and 18 are an upper preload jig and a lower preload jig for the outer bearing, which are prepared separately from the preload jigs 15 and 16 for the inner bearing, respectively. These preloading jigs 15 and 16 for bearings can also be used, and the design can be changed within the scope of the present invention.

  In the present embodiment, there is shown a mode in which a difference is provided in the width dimension between the outer rings 1a, 2a and the inner rings 1b, 2b of the two inner bearings 1, 2, but the inner ring and outer ring of two or more bearings There is no limitation as long as a difference is provided in the width dimension.

Example 2 is shown in FIG.
In this embodiment, the four bearings 1, 2, 3 and 4 are configured such that the width dimension L1 of the inner rings 1b, 2b, 3b and 4b is narrower than the width dimension L2 of the outer rings 1a, 2a, 3a and 4a. Has been. A raceway groove d is provided at a position shifted (offset) from the center of the width of each of the outer ring 1a (2a, 3a, 4a) and the inner ring 1b (2b, 3b, 4b). In addition, there is no sealing plate on the inner side, so that the bearing width dimension can be reduced correspondingly and the width dimension of the entire apparatus is reduced. The preload setting is the same as in the first embodiment.

According to the present embodiment, the inner bearing outer rings 1a, 2a have opposite end faces 1c, 1d abutting against the stepped end faces 11, 12 of the housing 9, and the outer bearing outer rings 3a, 4a are respectively end faces. 3c and 4c are in contact with inner bearing outer ring end faces 1d and 2d. Further, the inner bearing inner rings 1b and 2b are positioned such that the opposed end faces 1e and 2e are respectively spaced from the stepped end faces 11 and 12 of the housing 9 with desired gaps S1 and S2, and the outer bearing inner rings 3b. , 4b are positioned with desired gaps S3, S4 between the end surfaces 1f, 2f of the inner bearing inner rings 1b, 2b.
Other configurations, functions, and effects are the same as those in the first embodiment, and thus description thereof is omitted.

Example 3 is shown in FIG.
In the present embodiment, the inner bearings 1 and 2 have no sealing plate, and the bearing width dimension W1 is narrower than the width dimension W2 of the outer bearings 3 and 4. Further, in this embodiment, the inner bearings 1 and 2 are not provided with any sealing plate, and the bearing width dimension can be reduced correspondingly, thereby reducing the overall width dimension of the apparatus.

The inner two bearings 1 and 2 have the same outer ring width L2 and inner ring width L1, but the two outer bearings have a smaller inner ring width L1 than the outer ring width L2. ing.
Further, in this embodiment, the housing step portion 10 has a step 14, and the portions of the inner bearings 1 and 2 where the outer ring end surfaces 1c and 2c face each other are opposed to the portions where the inner ring end surfaces 1e and 2e face each other. Projects outward in the direction. Accordingly, the outer ring end surfaces 1c and 2c of the inner bearings 1 and 2 are in contact with the housing stepped end surfaces 11 and 12, but the inner ring end surfaces 1e and 2e are not in contact but are positioned with desired gaps S1 and S2. Further, the end faces 3d, 4d of the outer bearing inner rings 3b, 4b are positioned with desired gaps S3, S4 between the end faces 1f, 2f of the inner bearing inner rings 1b, 2b.

The inner rings 3b and 4b of the outer bearings 3 and 4 are in positions where the position of the raceway groove d is shifted (offset) from the center of the width. In the outer bearings 3, 4, the end faces 3e, 4e of the outer rings 3a, 4a opposite to the inner bearings 1, 2 and the end faces 3d, 4d of the inner rings 3b, 4b coincide with each other on the same plane. The inner bearings 1 and 2 have an inner ring width dimension L1 that is narrower than the outer ring width dimension L2.
Other configurations, functions, and effects are the same as those in the first embodiment, and thus description thereof is omitted.

A fourth embodiment of the present invention is shown in FIG.
This embodiment has the same bearing configuration as that of the first embodiment, but the length of the housing step 10 located between the inner bearings 1 and 2 is shorter than that of the housing step 10 of the first embodiment. In addition, a spacer 19 is provided between the inner inner rings 1 b and 2 b between the step portion tip 13 and the shaft outer diameter 8 a, and the inner inner rings 1 b and 2 b are pressed against each other by the spacer 19.
Further, according to this embodiment, the inner outer ring 1a has the end surface 1c abutting against the housing step end surface 11, but the other outer ring 1b does not hit the housing step end surface 12, and the gap Arranged with S5.
In the present embodiment, a collar portion 8 b is provided at one end of the shaft 8.
20 and 21 in the figure indicate an upper preload jig and a lower preload jig for the inner bearing.
In this case, the two inner bearings and the two outer bearings can be bonded and fixed by setting the preload at a time using the aforementioned preload jig.
In the figure, the end surface 1c portion of the outer ring 1a is abutted against the housing stepped end surface 12, but it may be adhered and fixed while adjusting the relative position between the shaft and the housing without abutting both outer ring end surface portions. .
Other configurations, functions, and effects are the same as those in the first embodiment, and thus description thereof is omitted.

A fifth embodiment of the present invention is shown in FIG.
This embodiment has the same bearing configuration as that of the third embodiment, but the length of the housing step 10 located between the inner bearings 1 and 2 is shorter than that of the housing step 10 of the third embodiment. In addition, a spacer 19 is provided between the inner inner rings 1 b and 2 b between the step portion tip 13 and the shaft outer diameter 8 a, and the inner inner rings 1 b and 2 b are pressed against each other by the spacer 19.
Further, according to the present embodiment, since the step 14 is provided on the housing step end surface 11 opposite to the inner one outer ring end surface 1c, the outer ring end surface 1c abuts against the housing step 10, Since the housing step portion end surface 12 facing the outer ring end surface 2c has no step, the other outer ring end surface 2c does not abut against the housing step end surface 12 and is provided with a gap S5.
Since the preload setting method is the same as the method described in the description of the fourth embodiment, the description thereof is omitted in this embodiment.
Other configurations, functions, and effects are the same as those in the first and third embodiments, and thus description thereof is omitted.

A sixth embodiment of the present invention is shown in FIG.
This embodiment has the same bearing configuration as that of the second embodiment, but the length of the housing step 10 located between the inner bearings 1 and 2 is shorter than that of the housing step 10 of the second embodiment. In addition, a spacer 19 is provided between the inner inner rings 1 b and 2 b between the step portion tip 13 and the shaft outer diameter 8 a, and the inner inner rings 1 b and 2 b are pressed against each other by the spacer 19.
Further, according to this embodiment, one outer ring end surface 1c on the inner side is in contact with the housing step portion 10, but the other outer ring end surface 2c is not in contact with the housing step portion end surface 12, and is provided with a gap S5. . In the present embodiment, a collar portion 8 b is provided at one end of the shaft 8.
Since the preload setting method is the same as the method described in the description of the fourth embodiment, the description thereof is omitted in this embodiment.
Other configurations, functions, and effects are the same as those in the first and second embodiments, and thus description thereof is omitted.

Sectional drawing which shows Example 1 of this invention. (A) shows a state where preload is applied to the inner bearing of the first embodiment, and (b) shows a state where preload is applied to the outer bearing of the first embodiment. Sectional drawing which shows Example 2. FIG. Sectional drawing which shows Example 3. FIG. Sectional drawing which shows Example 4. FIG. Sectional drawing which shows Example 5. FIG. Sectional drawing which shows Example 6. FIG.

Explanation of symbols

1, 2: Inner bearing 3, 4: Outer bearing 8: Shaft 9: Housing 19: Spacer d: Track groove L1: Inner ring dimension width L2: Outer ring dimension width W1, W2: Bearing width dimension

Claims (9)

  A bearing device in which four ball bearings are incorporated in a shaft and preloaded in the axial direction, wherein a difference is provided in the width dimension between an inner ring and an outer ring of two or more bearings.   2. The bearing device according to claim 1, wherein a width dimension of the ball bearing incorporated in the inner side in the axial direction is made narrower than a width dimension of the ball bearing incorporated in the outer side.   A spacer is provided between the inner rings of the two ball bearings facing each other on the inner side in the axial direction, and at least one of the outer rings constituting each inner ball bearing is not abutted. The bearing device according to claim 1 or 2.   The bearing device according to any one of claims 1 to 3, wherein a width dimension of the inner ring is narrower than a width dimension of the outer ring.   5. The bearing device according to claim 1, wherein the ball bearing incorporated inside does not include a sealing plate.   6. The bearing device according to claim 1, wherein each of the ball bearings has a respective raceway groove that is offset from a central position in the axial width of each of the inner ring and the outer ring.   7. A bearing device according to claim 1, wherein two ball bearings incorporated on the inner side are preloaded and fixed first, and then the ball bearings incorporated on both outer sides are preloaded and fixed. .   A pivot bearing device for an HDD comprising the bearing device according to claim 1. A method for assembling the bearing device according to any one of claims 1 to 6,
Two ball bearings to be incorporated on the inside are preloaded and fixed in advance.
Thereafter, a ball bearing assembled on both outer sides is fixed by applying a preload to the ball bearing.

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