JP2016091588A - Pivot assembly bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pivot assembly bearing that facilitates a narrower labyrinth gap for suppression of leakage and scattering of the lubricating oil and for contamination suppression of foreign matter.SOLUTION: A pivot assembly bearing 10A includes a shaft 40, and a sleeve 20 rotatably supported in an outer circumference of the shaft 40 through a pair of roller bearings 30. While applying preload in an inner ring 31 of one roller bearing 30 toward the axial inside, an end face 31a of the inner ring 31 is positioned in the axial inside more than the end face 32a of an outer ring 32 by fixing the inner ring 31 to the shaft 40, and a seal plate 50 being brought into abutment with the end face 32a of the outer ring 32 is fixed in an inner circumferential surface of the sleeve 20. A first labyrinth gap 61 is formed between the seal plate 50 and the end face 31a of the inner ring 31, and a second labyrinth gap 62 is formed between the seal plate 50 and the shaft 40.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a pivot assembly bearing used in a magnetic disk drive or the like, and more particularly to a seal structure using a labyrinth gap.

  This type of pivot assembly bearing generally has a structure in which a sleeve is rotatably supported on the outer periphery of a shaft via a rolling bearing, and the rolling bearing is provided in a pair of states separated in the axial direction. There are many. Between the shaft and the sleeve at both axial ends, a ring-shaped seal member or shaft is connected to prevent leakage or scattering of the lubricating oil filled in the rolling bearing, or to prevent foreign matter from entering. It is known that an integral flange portion is disposed and a labyrinth-like gap is formed between the seal or flange portion and a rolling bearing or shaft (Patent Documents 1 and 2, etc.).

JP 2006-077924 A JP 2008-069920 A

  The labyrinth-like gap (hereinafter referred to as labyrinth gap) described in the above-mentioned patent document is formed by, for example, fixing a seal member to a sleeve or a shaft by bonding or the like. The labyrinth gap is preferably as narrow as possible in terms of its function. However, in order to narrow the labyrinth gap, it is necessary to improve component processing accuracy and assembly accuracy by adhesion, which is difficult. In recent years, as the storage density of magnetic disk devices has increased, there has been a strong demand for pivot assembly bearings that can more reliably suppress the leakage of lubricant.

  The present invention has been made in view of the above, and its main purpose is to easily form a narrower labyrinth gap for suppressing the leakage and scattering of lubricating oil or the mixing of foreign substances. A pivot assembly bearing capable of maintaining cleanliness in a hard disk drive is provided.

  The pivot assembly bearing of the present invention includes a sleeve, a shaft inserted into the sleeve, an inner ring fixed to the shaft, an outer ring fixed to the sleeve, and a roller interposed between the inner ring and the outer ring. A pivot assembly including a moving body and a pair of rolling bearings spaced apart in the axial direction between the sleeve and the shaft, at least at one end in the axial direction, the inner ring A preload is applied to the inner side in the axial direction so that the end face of the inner ring is positioned axially inward of the end face of the outer ring, and the end face of the inner ring comes into contact with the end face of the outer ring at the one end. A first labyrinth gap is formed between the first labyrinth and an end structure provided with a seal member that forms a second labyrinth gap between the shaft and the shaft (claim 1).In this invention, the said edge part structure includes the form provided in the axial direction both ends (Claim 2).

  According to the pivot assembly bearing of the present invention, the first labyrinth gap obtained by applying a preload to the end face of the inner ring is equivalent to the internal gap formed inside the original rolling bearing. The labyrinth gap can be formed easily and more narrowly. For this reason, it is possible to more effectively prevent leakage or scattering of the lubricating oil or mixing of foreign matter from the outside.

  Next, a hard disk drive device according to the present invention is provided with the pivot assembly bearing according to claim 1 or 2 that supports a magnetic head arm for moving the magnetic head on the magnetic disk in a swingable manner. Claim 3).

  According to the present invention, a pivot assembly that can easily form a narrower labyrinth gap for suppressing leakage and scattering of lubricating oil or for preventing foreign matter from being mixed, thereby maintaining cleanliness in the hard disk drive. There is an effect that a bearing is provided.

(A) The perspective view which shows the hard-disk drive device with which the pivot assembly bearing which concerns on one Embodiment was applied, (b) It is a perspective view of a pivot assembly bearing. 1 is an overall cross-sectional view of a pivot assembly bearing according to an embodiment. It is a partially expanded sectional view which shows the labyrinth clearance gap formed in the edge part of the right side of FIG. It is a partially expanded sectional view of the edge part of the left side of FIG. It is sectional drawing which shows the labyrinth clearance gap formed in the part shown in FIG. It is a whole sectional view of a pivot assembly bearing concerning other embodiments of the present invention. It is sectional drawing which shows the principal part of the pivot assembly bearing of other embodiment.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[1] Configuration of One Embodiment FIG. 1A shows a hard disk drive 1 that is one of storage devices of a computer to which a pivot assembly bearing 10A according to an embodiment is applied. In this hard disk drive 1, information is transferred to the magnetic disk 5 by moving the magnetic head 4 provided at the tip of the magnetic head arm 3 supported so as to be swingable by the pivot assembly bearing 10 </ b> A on the magnetic disk 5. Recording is performed, and the recorded information is read from the magnetic disk 5.

  As shown in FIG. 1B, the pivot assembly bearing 10A is inserted into a rolling bearing 30 disposed inside the cylindrical sleeve 20, whereby the sleeve 20 and the shaft 40 shown in FIG. Is a bearing device that enables relative rotation.

  In the pivot assembly bearing 10A, the shaft 40 is fixed to the shaft support portion 7 provided at the bottom of the case 6 shown in FIG. 1A, and the sleeve 20 rotates. The sleeve 20 is press-fitted into the mounting hole 2 a of the base 2 of the magnetic head arm 3, and the magnetic head arm 3 swings as the sleeve 20 rotates.

Hereinafter, a pivot assembly bearing 10A according to an embodiment will be described with reference to FIGS.
As shown in FIG. 2, the pivot assembly bearing 10 </ b> A has a shaft 40 with a shaft 40 interposed between a pair of rolling bearings 30 that are spaced apart in the axial direction (left-right direction in FIG. 2) inside a cylindrical sleeve 20. It has a structure that is rotatably supported.

  The rolling bearing 30 is a ball bearing that includes an inner ring 31 and an outer ring 32, and a plurality of spherical rolling elements 33 are held between the inner ring 31 and the outer ring 32. The plurality of rolling elements 33 are held by a retainer (not shown) fitted between the inner ring 31 and the outer ring 32 so as to be rotatable and in a row in the circumferential direction. The inner ring 31 is fixed to the outer peripheral surface of the shaft 40, and the outer ring 32 is fixed to the inner peripheral surface of the sleeve 20. The rolling bearing 30 is fixed to the shaft 40 and the sleeve 20 by means such as adhesion. In the rolling bearing 30, lubricating oil such as grease is enclosed between the inner ring 31 and the outer ring 32.

  The shaft 40 has a cylindrical shape having a hollow portion 40a at the axis, and a flange portion 41 is formed at the right end in FIG. The flange part 41 has a disk part 41b extending in the radial direction and a cylindrical part 41c protruding in the axial direction from the outer periphery of the disk part 41b. On the end surface of the shaft 40 on the side where the flange portion 41 is formed, an annular convex portion 42 is provided so as to surround the opening of the hollow portion 40a. The outer peripheral surface of the cylindrical portion 41 b of the flange portion 41 faces an annular recess 20 a formed at the end of the inner peripheral surface of the sleeve 20. The inner peripheral surface of the cylindrical portion 41 b of the flange portion 41 faces the outer peripheral surface of the outer ring 32 of the right rolling bearing 30. An annular groove 41a is formed on the inner surface side of the flange portion 41, and the end surface of the outer ring 32 in the right rolling bearing 30 is opposed to the annular groove 41a. The inner ring 31 of the right rolling bearing 30 is preloaded on the inner side in the axial direction by pressing the inner surface of the flange portion 41 against the inner ring 31.

  As shown in FIG. 3, a labyrinth gap 63 is formed between the flange portion 41 and the outer ring 32 of the right rolling bearing 30 and the inner peripheral surface of the sleeve 20. Further, a labyrinth gap 63 a is formed between the end surface of the outer ring 32 of the rolling bearing 30 and the disk portion 41 b of the flange portion 41, and a labyrinth gap 63 b between the outer peripheral surface of the outer ring 32 and the cylindrical portion 41 c of the flange portion 41. Is formed. Thereby, the labyrinth gap of a longer distance than before is obtained.

  A spacer portion 21 having an inner diameter smaller than both end portions is formed concentrically at the axially intermediate portion of the inner peripheral surface of the sleeve 20. As shown in FIG. 4, the stepped surface of the spacer portion 21 is formed with a positioning portion 21a orthogonal to the inner peripheral surface of the sleeve 20, and an inclined relief portion 21b cut out axially inward from the positioning portion 21a. ing. The two rolling bearings 30 are axially positioned by bringing the outer ring 32 into contact with the positioning portion 21a. In such a positioned state, the outer ring 32 is fixed to the inner peripheral surface of the sleeve 20 by means such as adhesion.

  An annular seal plate 50 is disposed in the left end of the pivot assembly bearing 10A in FIG. The seal plate 50 is disposed to close the gap between the sleeve 20 and the shaft 40, and the outer peripheral surface thereof is fixed to the inner peripheral surface of the sleeve 20 by means such as adhesion.

  As shown in FIG. 5, the end surface 31a of the inner ring 31 of the left rolling bearing 30 is axially inner than the end surface 32a of the outer ring 32 at the left end of the pivot assembly bearing 10A in FIG. It is located on the right). The seal plate 50 is in contact with the end surface 32a of the outer ring 32, the first labyrinth gap 61 is formed between the end surface 31a of the inner ring 31 and the inner peripheral surface of the seal plate 50 and the shaft 40. A second labyrinth gap 62 is formed between the two.

  In order to obtain the structure as described above, preload is applied to the inner ring 31 toward the inner side in the axial direction, and the inner ring 31 is fixed to the shaft 40 in this state. As a result, as shown in FIG. 5, the end surface 32a of the outer ring 32 is positioned on the axially outer side (left side in FIG. 5) from the end surface 31a of the inner ring 31 by an amount corresponding to the axial gap. Then, the seal plate 50 is brought into contact with the end surface 32 a of the outer ring 32 and the outer ring 32 and the seal plate 50 are fixed to the inner peripheral surface of the sleeve 20, so that the first between the seal plate 50 and the end surface 31 a of the inner ring 31. A labyrinth gap 61 is formed. By bringing the seal plate 50 into contact with the end surface 32a of the outer ring 32 positioned on the outer side in the axial direction from the end surface 31a of the inner ring 31, a labyrinth gap can be easily formed using a flat disk having no step as the seal plate 50. be able to. Therefore, the seal plate 50 can be manufactured at a low cost by pressing or the like. A second labyrinth gap 62 is formed between the seal plate 50 and the shaft 40. The second labyrinth gap 62 can be formed by means such as adjusting the inner diameter of the seal plate 50, but the second labyrinth gap 62 is preferably smaller than the first labyrinth gap 61.

[2] Action and Effect of One Embodiment In the pivot assembly bearing 10A described above, leakage or scattering of the lubricating oil filled in the inside or contamination from the outside is caused at the left end where the seal plate 50 is disposed. The first labyrinth gap 61 and the second labyrinth gap 62 are suppressed by the labyrinth gap 63, the labyrinth gap 63a, and the labyrinth gap 63b at the right end where the flange portion 41 is formed.

  Here, in the present embodiment, the first labyrinth gap 61 obtained by applying a preload to the end surface 31a of the inner ring 31 of the rolling bearing 30 is originally at the left end where the seal plate 50 is disposed. This is equivalent to the internal gap formed inside the rolling bearing 30. Therefore, the first labyrinth gap 61 can be formed easily and narrower than before. For this reason, it is possible to more effectively prevent leakage or scattering of the lubricating oil or mixing of foreign matter from the outside.

[3] Other Embodiments Next, with reference to FIGS. 6 and 7, a pivot assembly bearing 10 </ b> B according to another embodiment having a configuration similar to the above-described embodiment will be described. In the reference drawing, the same reference numerals are given to the same components as those of the above-described embodiment, and the description thereof is omitted.

  The pivot assembly bearing 10 </ b> B according to another embodiment has the same labyrinth clearance structure at both ends, and the flange portion 41 is not formed on the shaft 40. In the one embodiment, a seal plate 50 fixed to the inner peripheral surface of the sleeve 20 is disposed at the right end portion that is closed by the flange portion 41 of the shaft 40. At both ends, an annular outer seal plate 51 is disposed outside each seal plate 50. The outer seal plate 51 is fixed to the shaft 40 by press-fitting or bonding step portions 43 formed at both ends of the shaft 40, and is disposed inside the both ends of the sleeve 20 in the fixed state. . As shown in FIG. 7, gaps 64 and 65 are formed between the outer seal plate 51, the sleeve 20, and the seal plate 50, respectively.

  A seal plate 50 and an outer seal plate 51 are disposed at both ends of the pivot assembly bearing 10B. As shown in FIG. 7, the seal plate 50 is in contact with the end surface 32 a of the outer ring 32 at the both ends as shown in FIG. 7, and between the seal plate 50 and the end surface 31 a of the inner ring 31. In addition, a first labyrinth gap 61 is formed, and a second labyrinth gap 62 is formed between the seal plate 50 and the shaft 40.

  Even in other embodiments, the first labyrinth gap 61 is formed by applying a preload to the end surface 31 a of the inner ring 31 of each rolling bearing 30 as in the above-described embodiment. Therefore, the first labyrinth gap 61 can be formed easily and as narrowly as possible. As a result, the pivot assembly bearing 60B can more effectively leak or scatter lubricating oil or foreign matter from the outside. It can prevent mixing.

  The hard disk drive 1 shown in FIG. 1 in which the magnetic head arm 3 is swingably supported by the pivot assembly bearing 10A (10B) according to each of the above embodiments can maintain the internal cleanliness. It becomes possible to improve the reliability of the apparatus.

DESCRIPTION OF SYMBOLS 1 ... Hard disk drive device 3 ... Magnetic head arm 4 ... Magnetic head 5 ... Magnetic disk 10A, 10B ... Pivot assembly bearing 20 ... Sleeve 30 ... Rolling bearing 31 ... Inner ring 31a ... End surface 32 of inner ring ... Outer ring 32a ... End surface 33 of outer ring Rolling element 40 ... Shaft 50 ... Seal plate (seal member)
61 ... 1st labyrinth gap 62 ... 2nd labyrinth gap

Claims (3)

Sleeve,
A shaft inserted into the sleeve;
An inner ring fixed to the shaft, an outer ring fixed to the sleeve, and a rolling element interposed between the inner ring and the outer ring, and spaced apart in the axial direction between the sleeve and the shaft. A pair of rolling bearings installed;
With
At least at one end in the axial direction, a preload is applied to the inner ring toward the inner side in the axial direction, whereby the end face of the inner ring is positioned axially inward from the end face of the outer ring, and And an end portion structure in which a seal member is formed to contact the end surface of the outer ring and form a first labyrinth gap between the inner ring and the shaft, and to form a second labyrinth gap between the shaft and the shaft. This is a pivot assembly bearing.   The pivot assembly bearing according to claim 1, wherein the end structures are provided at both axial ends.   A hard disk drive comprising the pivot assembly bearing according to claim 1 or 2, wherein a magnetic head arm for moving the magnetic head on the magnetic disk is supported in a swingable manner.

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