JP2015130217A - Bearing device and information record reproduction device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bearing device and information record reproduction device that allow a stationary position of a hub cap to be highly appropriately positioned.SOLUTION: A bearing device comprises: a shaft 20; a rolling bearing that is externally inserted into the shaft 20; a sleeve that is formed so as to surround an outer peripheral face of the rolling bearing and is disposed coaxially with the shaft; and a hub cap 80 that is press-fitted to one of the outer peripheral face of the shaft 20 and an inner peripheral face of a rotating member, and covers the rolling bearing from an outer side in an axial direction of the rolling bearing. Of the outer peripheral face of the shaft 20 and the inner peripheral face of the rotating member, a press-fit peripheral face 21 into which the hub cap 80 is press-fitted and a press-fit peripheral face 81 of any one of the inner peripheral face of the hub cap 80 and the outer peripheral face thereof and becoming a peripheral face to be press-fitted into the press-fit peripheral face 21 are formed so that respective crest parts of process grids abut against each other in a state where the press-fit peripheral faces 21 and 81 are press-fitted.

Description

  The present invention relates to a bearing device and an information recording / reproducing 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 on a disk (magnetic recording medium) is known. In general, an information recording / reproducing apparatus includes a head gimbal assembly including a slider for recording / reproducing a signal on / from a disk, and an arm (rotating member) having the head gimbal assembly mounted on the distal end side. This arm is rotatable by a bearing device provided on the base end side. By rotating the arm, the slider can be moved to a predetermined position on the disk to record and reproduce signals.

  In the bearing device, there are a shaft, a pair of rolling bearing portions that are extrapolated to the shaft and arranged in the axial direction of the shaft, and an annular plate-like shape that is press-fitted into the shaft and covers the rolling bearing from the outside in the axial direction. And a hub cap. The hub cap is for preventing gas and dust generated from grease or the like filled in the rolling bearing from being released to the outside.

  Here, if gas or dust generated from grease or the like is released to the outside, the gas or dust adheres to the tip of the disk or arm, which causes recording and reproduction failure and damage to the arm. For this reason, it is important to manage the size of the gap between the rolling bearing and the hub cap. That is, by narrowing the space between the rolling bearing and the hub cap as much as possible, it is possible to effectively prevent the gas and dust generated from the grease and the like from being discharged to the outside.

JP 2004-92870 A JP 2013-48005 A

However, in the above-described prior art, there is a problem that when the hub cap is press-fitted into the shaft, it is difficult to accurately position the fixing position of the hub cap by stick slip.
Here, stick slip refers to a phenomenon in which sticking (stick) and sliding (slip) are repeatedly performed by the action of friction. In particular, when two members subjected to lathe processing are press-fitted or the like, a crest portion of a processing member of one member and a trough portion of a processing member of the other member are often fitted, and stick slip is often generated. Thus, in the process of press-fitting the hub cap into the shaft, if the hub cap does not move smoothly and stick-slip occurs, it is difficult to accurately position the hub cap.

  If the hub cap cannot be positioned with high precision and the space between the rolling bearing and the hub cap expands, it will not be possible to suppress the release of gas and dust generated from grease and the like to the outside. . On the other hand, if the hub cap is too close to the rolling bearing, the hub cap comes into contact with the outer ring of the rolling bearing, resulting in a defective rotation of the arm.

  Accordingly, the present invention has been made in view of the above-described circumstances, and provides a bearing device and an information recording / reproducing device capable of positioning a hub cap fixed position with high accuracy.

  In order to solve the above-mentioned problems, a bearing device according to the present invention is formed so as to surround a shaft, a rolling bearing inserted into the shaft, and an outer peripheral surface of the rolling bearing, and is coaxial with the shaft. A rotating member disposed so as to be rotatable with respect to the shaft, and press-fitted into one of an outer peripheral surface of the shaft and an inner peripheral surface of the rotating member, and the rolling bearing is connected to the shaft A hub cap that covers from the outside in the axial direction of the shaft, and of the outer peripheral surface of the shaft and the inner peripheral surface of the rotating member, a first press-fitting peripheral surface that is a peripheral surface into which the hub cap is press-fitted, and The second press-fit peripheral surface, which is either the inner peripheral surface or the outer peripheral surface of the hub cap and serves as a peripheral surface to be press-fitted into the first press-fit peripheral surface, is the first press-fit peripheral surface and the second press-fit peripheral surface. In a state where and are press-fitted, Wherein the each other crest of processing marks the respectively are formed so as to abut.

  With this configuration, when the hub cap is in the press-fitted state, any one of the processed parts of the first press-fitted peripheral surface and the processed part of the second press-fitted peripheral surface fits into the valley part of the other processed part. Can be prevented. For this reason, in the press-fit state of the hub cap, stick slip can be prevented from occurring in the hub cap, and the hub cap can be smoothly moved. Therefore, the fixing position of the hub cap can be positioned with high accuracy.

  The first press-fitting peripheral surface and the second press-fitting peripheral surface of the bearing device according to the present invention are each formed by lathe processing, and a first pitch of the crest portion of the first press-fitting peripheral surface, The second pitch of the crests of the second press-fitting peripheral surface is set so that at least a part of the mutual pitch is different.

  Here, when lathe processing is performed on the first press-fitting peripheral surface and the second press-fitting peripheral surface, a crest and a trough are formed in a spiral shape in the processing stitch of each press-fitting peripheral surface. For this reason, the first pitch of the peak portion of the first press-fit peripheral surface and the second pitch of the peak portion of the second press-fit peripheral surface are set so that at least a part of the mutual pitch is different, In the press-fitted state of the hub cap, it is possible to prevent one of the crests of the first press-fitting peripheral surface and the second press-fitting peripheral surface from being fitted into the trough of the other processing. Therefore, stick slip can be prevented from occurring in the hub cap, and the fixing position of the hub cap can be positioned with high accuracy.

  The bearing device according to the present invention is characterized in that the first pitch is set to be constant and at least a part of the second pitch is set to a pitch different from the first pitch.

  In this way, changing the interval of the second pitch means changing the processing line of the second press-fitting peripheral surface of the hub cap. Since the processing of the hub cap can be easily performed as compared with the processing of the shaft and sleeve, the manufacturing cost of the entire bearing device can be reduced.

  In the bearing device according to the present invention, the first press-fitting peripheral surface and the second press-fitting peripheral surface are each formed by lathe machining, and the turning direction of the processing eye of the first press-fitting peripheral surface, The turning directions of the second press-fitting peripheral surface are set to be opposite to each other.

  The swivel direction of the first press-fit peripheral surface and the swivel direction of the second press-fit peripheral surface are set to be opposite to each other. That is, they are set in opposite directions. For this reason, in the press-fitted state of the hub cap, either one of the crests of the first press-fitting peripheral surface and the second press-fitting peripheral surface is fitted into the trough of the other process. Can be prevented. Therefore, the fixing position of the hub cap can be positioned with high accuracy.

  The bearing device according to the present invention is characterized in that knurling is performed on one of the first press-fitting peripheral surface and the second press-fitting peripheral surface so that a ridge line of the peak portion is along the axial direction. .

  With this configuration, when the hub cap is in the press-fitted state, any one of the processed parts of the first press-fitted peripheral surface and the processed part of the second press-fitted peripheral surface fits into the valley part of the other processed part. Can be prevented. For this reason, the fixed position of the hub cap can be positioned with high accuracy.

  The bearing device according to the present invention is characterized in that the first press-fitting peripheral surface is knurled.

  As described above, the knurling process is performed on the first press-fitting peripheral surface (particularly the shaft), so that the manufacturing cost can be reduced as compared with the case where the second press-fitting peripheral surface (hub cap) is subjected to the knurling process.

  An information recording / reproducing apparatus according to the present invention includes a bearing device, a housing that supports an end portion of the bearing device, a slider that is attached to the rotating member and records and reproduces information with a magnetic recording medium. , Provided.

  With this configuration, it is possible to prevent gas and dust generated from grease or the like of the bearing device from adhering to the rotating member and the magnetic recording medium. Therefore, it is possible to prevent defective recording and reproduction and damage to the arm, and provide a highly reliable information recording / reproducing apparatus.

  According to the present invention,

1 is a perspective view of an information recording / reproducing apparatus in a first embodiment of the present invention. It is sectional drawing which follows the AA line of FIG. It is an expanded sectional view of the important section of the bearing device in a 1st embodiment of the present invention. It is the B section enlarged view of FIG. It is an expansion perspective view of the shaft and hub cap in 2nd Embodiment of this invention. It is an expansion perspective view of the shaft and hub cap in 3rd Embodiment of this invention. It is a longitudinal cross-sectional view of the bearing apparatus in other embodiment of this invention.

(First embodiment)
Next, a first embodiment of the present invention will be described with reference to FIGS.
(Information recording / reproducing device)
FIG. 1 is a perspective view of the information recording / reproducing apparatus, and FIG. 2 is a cross-sectional view taken along line AA of FIG.
As shown in FIG. 1, the information recording / reproducing apparatus 1 is an apparatus that writes and reads data on a disk (magnetic recording medium) D having a recording layer.

  The information recording / reproducing apparatus 1 includes an arm (rotating member) 8, a head gimbal assembly 4 supported on the tip side of the arm 8, a slider 2 attached to the tip of the head gimbal assembly 4, and a head gimbal assembly 4. An actuator (VCM: voice coil motor) 6 for moving the scan, a spindle motor 7 for rotating the disk D, a control unit 5 for supplying a current modulated in accordance with information to the slider 2, and these components are housed inside. And a housing 9 to be provided.

  The housing 9 is made of a metal material such as aluminum and has a box-like shape having an opening at the top, and has a rectangular bottom 9a in plan view and a peripheral wall that stands vertically from the peripheral edge of the bottom 9a ( (Not shown). On the inner side of the housing 9 surrounded by the peripheral wall, a recess for accommodating the above-described components is formed. The above-described spindle motor 7 is attached to substantially the center of the bottom portion 9a, and the disk D is detachably fixed by fitting a center hole into the spindle motor 7.

  A bearing device 10 is disposed on the side of the disk D. As shown in FIG. 2, the bearing device 10 is inserted into a sleeve (rotating member) 8a, and the arm 8 is fixed to the outer peripheral surface of the sleeve 8a. As shown in FIG. 1, one side of the arm 8 across the bearing device 10 is connected to the actuator 6 described above. The other side of the arm 8 extends in parallel with the surface of the disk D, and the head gimbal assembly 4 is connected to the tip thereof.

The sleeve 8 a is formed in a cylindrical shape so as to surround the outer peripheral surface of the outer ring 40 of the rolling bearing 30, and is arranged coaxially with the shaft 20 (both will be described later).
The head gimbal assembly 4 includes a suspension 3 and a slider 2 that is attached to the tip of the suspension 3 and is disposed to face the surface of the disk D. The slider 2 includes a recording element for writing (recording) information on the disk D and a reproducing element for reading (reproducing) information from the disk D.

In the information recording / reproducing apparatus 1 configured as described above, in order to record or reproduce information, first, the spindle motor 7 is driven, and the disk D is rotated around the central axis L2.
Further, the actuator 6 is driven to rotate the arm 8 around the central axis L <b> 1 of the bearing device 10. As a result, the slider 2 disposed at the tip of the head gimbal assembly 4 can be scanned and moved to each part of the surface of the disk D. Then, by driving the recording element or reproducing element of the slider 2, information can be recorded or reproduced on the disk D.

(Bearing device)
FIG. 3 is an enlarged cross-sectional view of a main part of the bearing device. As shown in FIGS. 2 and 3, the bearing device 10 includes a shaft 20 and a pair of rolling bearings (a first rolling bearing 31 and a second rolling bearing that are extrapolated to the shaft 20 and arranged side by side in the axial direction of the shaft 20. Rolling bearing 32), a cylindrical spacer 70 disposed coaxially with the shaft 20 and disposed inside the axial direction of the pair of rolling bearings 31 and 32, and the shaft 20 are joined to each other. And a hub cap 80 covering from the outside in the axial direction.

  In the present application, a direction along the central axis (that is, the central axis of the shaft 20) L1 of the bearing device 10 is referred to as an “axial direction”. In the present application, the axially inner sides of the pair of rolling bearings 31 and 32 (the other rolling bearing side of the pair of rolling bearings 31 and 32 as viewed from one rolling bearing and the spacer 70 side of each rolling bearing 31 and 32). Is called the “inner side in the axial direction”, and the outer side in the axial direction of the pair of rolling bearings 31, 32 (the other side of the pair of rolling bearings 31, 32, the opposite side of the other rolling bearing, each rolling bearing The opposite side of the spacers 31 and 32 from the spacer 70 is referred to as “the outside in the axial direction”.

  The shaft 20 is formed in a substantially cylindrical shape from a metal material such as stainless steel, and is connected to the housing 9. A flange 25 is formed on one side of the shaft 20 in the axial direction. In addition, the shaft 20 is formed with a concave portion 27 that opens on an end surface in the axial direction of the shaft 20. The concave portion 27 penetrates the shaft 20 in the axial direction, and opens individually on both end surfaces of the shaft 20 in the axial direction. The recess 27 is arranged coaxially with the central axis L1.

As shown in FIG. 2, the bearing device 10 includes, as the rolling bearing 30, a first rolling bearing 31 disposed on one side in the axial direction of the shaft 20 and a second rolling bearing disposed on the other side in the axial direction of the shaft 20. And a rolling bearing 32.
In addition, the 1st rolling bearing 31 and the 2nd rolling bearing 32 are the same shapes, and are arrange | positioned at the surface object. The first rolling bearing 31 is arranged with the side surface of the inner ring 36 in contact with the flange 25. The first rolling bearing 31 is covered from the outside in the axial direction by the flange 25.

  As shown in FIG. 3, the rolling bearing 30 includes an inner ring 36 fixed to the shaft 20, an outer ring 40 that abuts against an end surface in the axial direction of the spacer 70, and a plurality of rollers disposed between the inner ring 36 and the outer ring 40. A rolling element 35, a retainer 50 that holds the rolling element 35 so as to be freely rotatable, a shield (outer shield 60b) that is disposed on both sides in the axial direction of the rolling element 35 and seals a gap between the inner ring 36 and the outer ring 40; It has. A sleeve 8 a is fitted and fixed to the outer peripheral surface of the outer ring 40.

The inner ring 36 and the outer ring 40 are formed in a substantially cylindrical shape from a metal material.
A rolling groove 38 is formed at the axial center of the outer peripheral surface of the inner ring 36. The rolling groove 38 is formed over the entire circumference of the inner ring 36.
An outer ring main body 45 is formed near the center of the outer ring 40 in the axial direction. A rolling groove 48 is formed at the center in the axial direction of the outer ring 40 on the inner peripheral surface of the outer ring main body 45. The rolling groove 48 is formed over the entire circumference of the outer ring main body 45.
The rolling element 35 is formed in a spherical shape from a metal material. The rolling element 35 is disposed inside each rolling groove 38, 48 and rolls along each rolling groove 38, 48.

  Here, an outer shield holding portion 40b for holding the outer shield 60b is formed on the outer side of the outer ring main body portion 45 in the axial direction. On the other hand, a spacer holding portion 40 a that holds a spacer protrusion 72 described later is formed on the inner side of the outer ring main body portion 45 in the axial direction.

  The outer diameter of the outer ring 40 is the same for the entire axial direction of the outer ring 40. On the other hand, the inner diameter of the outer ring 40 is formed such that the inner diameter of the outer ring main body 45 is minimized. The inner diameter of the spacer holding portion 40 a and the inner diameter of the outer shield holding portion 40 b are equal and are formed larger than the inner diameter of the outer ring main body portion 45.

  The outer shield 60 b is disposed on the inner side in the radial direction of the contact portion 63 and the contact portion 63 that contacts the side surface in the axial direction of the outer ring main body 45, and seals the gap between the inner ring 36 and the outer ring 40. And a connecting portion 62 that connects the contact portion 63 and the sealing portion 61. Further, the outer shield 60 b includes a claw portion 65 erected from the outer periphery of the contact portion 63 in the direction opposite to the rolling element 35. For example, a plurality of claw portions 65 are formed at equal angular intervals in the circumferential direction of the outer shield 60b.

  When the outer shield 60b is press-fitted between the inner ring 36 and the outer ring 40, the claw portion 65 comes into contact with the inner peripheral surface of the outer shield holding portion 40b of the outer ring 40, and the claw portion 65 faces inward in the radial direction of the outer shield 60b. Bends (elastically). Thereby, the outer shield 60b is held on the inner peripheral surface of the outer shield holding portion 40b.

  As shown in FIG. 2, the spacer 70 is formed in a cylindrical shape from a metal material. The outer diameter of the spacer 70 is slightly smaller than the outer diameter of the outer ring 40 of the rolling bearing 30. As shown in FIG. 3, spacer protrusions 72 are formed on both end surfaces of the spacer 70 in the axial direction. The spacer protrusion 72 is formed in a ring shape coaxial with the spacer 70. The outer diameter of the spacer protrusion 72 is formed to be equal to the inner diameter of the spacer holding portion 40 a of the outer ring 40.

  The hub cap 80 is a plate material formed in a substantially circular shape in a plan view when viewed from the axial direction with a metal material such as stainless steel, for example, and covers the second rolling bearing 32 from the outside in the axial direction. A small axial gap S <b> 1 is provided between the inner surface 80 a facing the inner side in the axial direction of the hub cap 80 and the second rolling bearing 32. The minute gap S1 is set to such a size that gas or dust generated from grease or the like filled in the rolling bearing 30 is not released to the outside.

  Further, the outer diameter of the hub cap 80 is set substantially equal to the outer diameter of the second rolling bearing 32. On the other hand, the inner diameter of the hub cap 80 is set to be slightly smaller than the outer diameter of the shaft 20. Thereby, the hub cap 80 is fixed by being press-fitted into the shaft 20. That is, the outer peripheral surface corresponding to the hub cap 80 of the shaft 20 is a press-fit peripheral surface (first press-fit peripheral surface) 21, and the inner peripheral surface of the hub cap 80 is a press-fit peripheral surface (second press-fit peripheral surface) 81. Is done.

  Here, the press-fitting peripheral surface 21 of the shaft 20 and the press-fitting peripheral surface 81 of the hub cap 80 are formed by lathing the surfaces. Hereinafter, the processing stitches (surface roughness) of the press-fit peripheral surfaces 21 and 81 will be described in detail.

FIG. 4 is an enlarged view of a portion B in FIG. In each drawing used in the following description, the scale of each part is appropriately changed so that each part can be recognized.
As shown in FIG. 4, the press-fitting peripheral surface 21 of the shaft 20 is formed by performing a lathe process, and therefore, a crest portion 21 a and a trough portion 21 b are formed in that order, and each crest portion is formed. 21a and trough part 21b will be in the state formed in spiral. The press-fitting peripheral surface 21 is formed such that the pitch P1 of the peak portions 21a is a constant pitch. The pitch P1 is set to about 10 μm, for example.

On the other hand, the press-fitting peripheral surface 81 of the hub cap 80 is also formed by lathe processing, so that the processing portion is formed with a peak portion 81a and a valley portion 81b in order, and a peak portion 81a and a valley portion, respectively. 81b is formed in a spiral shape.
Here, the press-fitting peripheral surface 81 is formed such that the pitch P2 of the crests 81a in a part of the whole is different from the pitch P3 of the crests 81a in other parts.
In the following description, in the press-fit peripheral surface 81, a range in which the peak portions 81a are formed at the pitch P2 is referred to as a range X, and a range in which the peak portions 81a are formed at the pitch P3 is referred to as a range Y.

  The range X of the press-fit peripheral surface 81 is set on the second rolling bearing 32 side (the lower side in FIG. 4) of the entire press-fit peripheral surface 81. The pitch P <b> 2 of the crest 81 a formed in the range X is set to a dimension different from the pitch P <b> 1 of the crest 21 a formed on the press-fit peripheral surface 21 of the shaft 20. For example, when the pitch P1 of the peak portion 21a is set to about 10 μm, the pitch P2 of the peak portion 81a in the range X is set to about 7 μm.

Here, it is desirable to set the dimensional relationship between the pitch P1 and the pitch P2 so that the common divisor is only one. In the case of the first embodiment, when the pitch P1 is 10 μm and the pitch P2 is 7 μm, the common divisor is only 1.
The range X is set to a range of at least 1/3 with respect to the thickness T1 of the hub cap 80. That is, if the thickness T1 of the hub cap 80 is 0.15 mm, for example, the range of at least 0.05 mm in thickness is set as the range X in the entire press-fitting peripheral surface 81 of the hub cap 80. The dimension of the range X with respect to the wall thickness T1 of the hub cap 80 is not limited to the above-mentioned 1/3, and may be smaller than 1/3.

  On the other hand, the range Y of the press-fit peripheral surface 81 is set on the side opposite to the second rolling bearing 32 (upper side in FIG. 4) in the entire press-fit peripheral surface 81. The pitch P3 of the ridges 81a formed in the range Y is set to be substantially the same as the pitch P1 of the ridges 21a formed on the press-fit peripheral surface 21 of the shaft 20. That is, when the pitch P1 of the peak 21a is set to about 10 μm, the pitch P3 of the peak 81a in the range Y is also set to about 10 μm.

(Operation when hub cap is assembled)
Next, an operation when the hub cap 80 is assembled to the shaft 20 will be described.
First, the hub cap 80 is press-fitted into the shaft 20 from the outer side in the axial direction of the second rolling bearing 32 (upper side in FIG. 4) toward the second rolling bearing 32 side (lower side in FIG. 4). Then, first, the range X of the press-fit peripheral surface 81 of the hub cap 80 contacts the press-fit peripheral surface 21 of the shaft 20. Then, the hub cap 80 is press-fitted into the shaft 20 as it is.

  At this time, the pitch P1 of the peak portion 21a on the press-fit peripheral surface 21 of the shaft 20 and the pitch P2 of the peak portion 81a in the range X among the press-fit peripheral surface 81 of the hub cap 80 are set to different pitches. In the press-fitting process of the hub cap 80, the peak portion 21a of the press-fit peripheral surface 21 and the peak portion 81a of the press-fit peripheral surface 81 are always in contact with each other. In other words, the peak portion 81 a of the hub cap 80 does not fit into the valley portion 21 b in the press-fit peripheral surface 21 of the shaft 20. For this reason, the hub cap 80 moves smoothly during the press-fitting process of the hub cap 80.

  While maintaining such a state, the hub cap 80 is press-fitted, and when the minute gap S1 between the inner surface 80a of the hub cap 80 and the second rolling bearing 32 reaches a predetermined dimension, the press-fitting operation of the hub cap 80 is performed. To stop. Thereby, the assembly of the hub cap 80 to the shaft 20 is completed.

  Here, as described above, the dimensional relationship between the pitch P1 and the pitch P2 is desirably set so that the common divisor is only one. When the common divisor exists other than 1, there are exactly two or more peak portions 81a of the hub cap 80 in the valley portion 21b of the press-fit peripheral surface 21 of the shaft 20. In such a case, exactly two or more peak portions 81a of the hub cap 80 are fitted into the valley portion 21b of the press-fitting peripheral surface 21 of the shaft 20, and the hub cap 80 is in the process of press-fitting the hub cap 80. May cause stick-slip.

  Thus, in the first embodiment described above, the pitch P2 of the crests 81a at some locations (range X) of the press-fitting peripheral surface 81 of the hub cap 80 is equal to the crests on the press-fitting peripheral surface 21 of the shaft 20. It is set to be different from the pitch P1 of 21a. For this reason, in the range X of the press-fitting peripheral surface 81 of the hub cap 80, in the press-fitting process of the hub cap 80, the crest portion 21a of the press-fitting peripheral surface 21 and the crest portion 81a of the press-fit peripheral surface 81 are always in contact. Therefore, in the press-fitting process of the hub cap 80, the hub cap 80 can be moved smoothly, and the minute gap S1 between the inner surface 80a of the hub cap 80 and the second rolling bearing 32 can be managed with high accuracy. become.

  Further, in processing the press-fit peripheral surface 81 of the hub cap 80, the pitch P2 of the peak portion 81a in the range X is set to about 7 μm, for example, whereas the pitch P3 of the peak portion 81a in the range Y is For example, it is set to about 10 μm. As described above, the pitch P2 of the peak portion 81a in the range X is set finely, while the pitch P3 of the peak portion 81a in the range Y is set coarsely, so that the entire press-fitting peripheral surface 81 of the hub cap 80 has high accuracy (for example, The processing man-hours can be shortened compared with finishing with a pitch interval of 7 μm. For this reason, the manufacturing cost of the hub cap 80 can be reduced.

  Here, it is also possible to set the pitch of the peak portions 81 a of the entire press-fit peripheral surface 81 of the hub cap 80 to be different from the pitch P 1 of the peak portions 21 a on the press-fit peripheral surface 21 of the shaft 20.

In the first embodiment described above, the press-fit peripheral surface 21 of the shaft 20 is formed so that the pitch P1 of the peak portions 21a is a constant pitch, while the press-fit peripheral surface 81 of the hub cap 80 is The case where the pitch P2 of the peak portion 81a of the portion (range X) is formed to be different from the pitch P1 has been described. However, the present invention is not limited to this, and the press-fitting peripheral surface 81 of the hub cap 80 is formed so that the crests 81a have a constant pitch, while the press-fitting peripheral surface 21 of the shaft 20 is formed with a part of the crests 21a. The pitch may be different from the pitch of the peaks 81a of the hub cap 80.
Since the processing of the shaft 20 requires a processing cost compared to the processing of the hub cap 80, the processing cost can be reduced by changing the pitch of the peak portions 81a of the hub cap 80.

  In the first embodiment described above, the pitch P1 of the crests 21a on the press-fitting peripheral surface 21 of the shaft 20 is set to, for example, about 10 μm, and the crests 81a in the range X on the press-fitting peripheral surface 81 of the hub cap 80 are set. The case where the pitch P2 is set to about 7 μm, for example, has been described. However, the present invention is not limited to this, and it is sufficient that the dimensions of the pitches P1 and P2 are different from each other, and the respective dimensions can be arbitrarily set.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG.
FIG. 5 is an enlarged perspective view of a shaft and a hub cap in the second embodiment. In addition, the same code | symbol is attached | subjected to the aspect same as 1st Embodiment, and description is abbreviate | omitted (same also about the following embodiment).

  As shown in FIG. 5, in the second embodiment, the press-fitting peripheral surface 21 of the shaft 20 and the press-fitting peripheral surface 81 of the hub cap 80 are formed by lathe processing, etc. This is the same as the embodiment. However, the turning direction of the crests 21a and troughs 21b formed on the press-fitting peripheral surface 21 of the shaft 20 and the turning direction of the crests 81a and troughs 81b formed on the press-fitting peripheral surface 81 of the hub cap 80 are: They are set in opposite directions, and this is different from the first embodiment described above.

  In order to form the turning direction of the crests 21a and troughs 21b of the shaft 20 and the turning direction of the crests 81a and troughs 81b of the hub cap 80 in opposite directions, a lathe machine (not shown) is used. When processing, the rotation direction of the base material (the shaft 20 and the hub cap 80) chucked by this lathe processing machine may be reversed.

  As described above, when the turning direction of the peak portion 21a and the valley portion 21b of the shaft 20 and the turning direction of the peak portion 81a and the valley portion 81b of the hub cap 80 are opposite to each other, in the press-fitting process of the hub cap 80, The peak portion 81 a of the hub cap 80 does not fit into the valley portion 21 b of the 20 press-fitting peripheral surfaces 21. That is, during the press-fitting process of the hub cap 80, the crest 21a of the press-fitting peripheral surface 21 and the crest 81a of the press-fitting peripheral surface 81 are always in contact.

  Therefore, according to the second embodiment described above, even if the pitch P4 of the peak portion 21a of the shaft 20 is the same as the pitch P5 of the peak portion 81a of the hub cap 80, the same as in the first embodiment described above. There is an effect.

  In the first and second embodiments described above, the case where the outer peripheral surface corresponding to the hub cap 80 of the shaft 20 is the press-fit peripheral surface (first press-fit peripheral surface) 21 has been described. However, the entire axial direction of the outer peripheral surface of the shaft 20 may be processed in the same manner as the press-fit peripheral surface 21.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG.
FIG. 6 is an enlarged perspective view of a shaft and a hub cap in the third embodiment.
As shown in the figure, in the third embodiment, the press-fitting peripheral surface 81 of the hub cap 80 is formed by performing a lathe process and the like, as in the first embodiment. However, a knurled portion 91 is formed on the press-fitting peripheral surface 21 of the shaft 20 by performing knurling, which is different from the first embodiment described above.

The knurled portion 91 is formed so that the ridge line at the peak portion 91a of the processed portion is along the central axis L1.
Under such a configuration, in the press-fitting process of the hub cap 80, the crest 91a of the knurled portion 91 and the crest 81a on the press-fitting peripheral surface 81 of the hub cap 80 are always in contact with each other.

Therefore, according to the above-described third embodiment, the same effects as those of the above-described first embodiment can be obtained.
In the above-described third embodiment, the case where the knurling process is performed on the press-fitting peripheral surface 21 of the shaft 20 has been described, but the press-fitting peripheral surface 81 of the hub cap 80 may be knurled.

The present invention is not limited to the above-described embodiment, and includes various modifications made to the above-described embodiment without departing from the spirit of the present invention.
For example, in each of the above-described embodiments, the case where the hub cap 80 is assembled by press-fitting the hub cap 80 into the shaft 20 has been described. However, the present invention is not limited to this, and the hub cap 80 may be press-fitted into the sleeve 8a as shown in FIG.

  In this case, the inner diameter of the hub cap 80 is set to be slightly larger than the inner diameter of the second rolling bearing 32 (the outer diameter of the shaft 20). On the other hand, the outer diameter of the hub cap 80 is set to be slightly smaller than the inner diameter of the sleeve 8a. Thereby, the hub cap 80 is fixed by being press-fitted into the sleeve 8a. That is, the inner peripheral surface of the sleeve 8a corresponding to the hub cap 80 is a press-fit peripheral surface (first press-fit peripheral surface) 8b, and the outer peripheral surface of the hub cap 80 is a press-fit peripheral surface (second press-fit peripheral surface) 82. Is done.

  Further, in the above-described embodiment, the bearing device 10 has the sleeve 8a that is externally fitted and fixed to the outer peripheral surface of the outer ring 40 of the rolling bearing 30, and the arm 8 is fixed to the outer peripheral surface of the sleeve 8a. Explained. However, the present invention is not limited to this, and the arm 8 may be directly fitted and fixed to the outer peripheral surface of the outer ring 40. In this case, the hub cap 80 may be press-fitted into the arm 8. That is, the inner peripheral surface corresponding to the hub cap 80 of the arm 8 may be a press-fit peripheral surface (first press-fit peripheral surface) 8b.

  Furthermore, in the above-described embodiment, the case where the cylindrical spacer 70 and the sleeve 8a arranged inside the pair of rolling bearings 31 and 32 in the axial direction are separated is described. However, the present invention is not limited to this, and the sleeve 8a and the spacer 70 may be integrally formed. Also, the shape of the spacer 70 can be arbitrarily designed.

  Furthermore, in order to secure a gap between the pair of rolling bearings 31 and 32, the spacer 70 may not be provided and the following configuration may be used. That is, the outer ring 40 of each of the rolling bearings 31 and 32 is extended and formed on the inner side in the axial direction by a predetermined length (for example, about ½ of the axial length of the spacer 70). And the inner ends of the axial direction in the outer ring | wheel 40 of each rolling bearing 31 and 32 are made to contact | abut. Thereby, you may comprise so that a clearance gap may be ensured between a pair of rolling bearings 31 and 32. FIG.

DESCRIPTION OF SYMBOLS 1 ... Information recording / reproducing apparatus 2 ... Slider 8 ... Arm (rotating member)
8a ... Sleeve (rotating member)
8b, 21 ... press-fit peripheral surface (first press-fit peripheral surface)
DESCRIPTION OF SYMBOLS 9 ... Housing 10 ... Bearing apparatus 20 ... Shaft 21a, 81a ... Mountain part 30 ... Rolling bearing 31 ... 1st rolling bearing 32 ... 2nd rolling bearing 80 ... Hub cap 81, 82 ... Press-fit peripheral surface (2nd press-fit peripheral surface)
91 ... Knurled portion P1 ... Pitch (first pitch)
P2 ... Pitch (second pitch)
P3, P4 ... Pitch D ... Disk (magnetic recording medium)

Claims (7)

A shaft,
A rolling bearing externally inserted into the shaft;
A rotating member that is formed so as to surround the outer peripheral surface of the rolling bearing and is arranged coaxially with the shaft, and is provided so as to be rotatable with respect to the shaft;
A hub cap that is press-fitted into one of the outer peripheral surface of the shaft and the inner peripheral surface of the rotating member, and covers the rolling bearing from the outside in the axial direction of the shaft,
Of the outer peripheral surface of the shaft and the inner peripheral surface of the rotating member, one of the first press-fit peripheral surface that is the peripheral surface into which the hub cap is press-fitted, and the inner peripheral surface and the outer peripheral surface of the hub cap And the second press-fitting peripheral surface, which is a peripheral surface that is press-fitted into the first press-fitting peripheral surface, is a crest of each machining in the state where the first press-fitting peripheral surface and the second press-fitting peripheral surface are press-fitted. A bearing device characterized in that the portions are formed so as to contact each other. The first press-fitting peripheral surface and the second press-fitting peripheral surface are each formed by lathe processing,
The first pitch of the crests of the first press-fitting peripheral surface and the second pitch of the crests of the second press-fitting peripheral surface are set so that at least a part of the mutual pitch is different. The bearing device according to claim 1.   The bearing device according to claim 2, wherein the first pitch is set to be constant, and at least a part of the second pitch is set to a pitch different from the first pitch. The first press-fitting peripheral surface and the second press-fitting peripheral surface are each formed by lathe processing,
2. The bearing device according to claim 1, wherein a turning direction of the machining of the first press-fit peripheral surface and a turning direction of the work of the second press-fit peripheral surface are set to be opposite to each other. .   2. The bearing device according to claim 1, wherein either one of the first press-fit peripheral surface and the second press-fit peripheral surface is knurled so that a ridge line of the peak portion is along the axial direction. .   The bearing device according to claim 5, wherein the first press-fitting peripheral surface is knurled. The bearing device according to any one of claims 1 to 6,
A housing that supports an end of the bearing device;
An information recording / reproducing apparatus comprising: a slider attached to the rotating member and configured to record and reproduce information with a magnetic recording medium.

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