JP2001012466A - Method of forming clearance between shaft fitting members - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of forming a specified clearance between shaft fitting members easily with high accuracy and high mass productivity at a low cost. SOLUTION: A first groove with a first depth and a second groove 6 with a second depth shallower by a portion of a thrust clearance 54 than the first depth are provided, and after the shaft reference end side of a shaft fitted into a journal bearing 58, a first thrust bearing and a second thrust bearing 52 is inserted in the first groove, the second thrust bearing 52 is rigidly fixed to the shaft so as to have no clearance between the journal bearing 58 and each of the first thrust bearing and second thrust bearing 52. The shaft reference end side is then inserted in the second groove 6, and in this state, the first thrust bearing is rigidly fixed to the shaft to form the thrust clearance 54 between the journal bearing 58 and each of the first thrust bearing and second thrust bearing 52.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gap forming method for forming a gap when a member fitted to a shaft rotates or slides, and more particularly to a magnetic field having a rotating bearing. The present invention relates to a motor bearing device used for a disk device, an optical disk device, a polygon mirror, and the like.

[0002]

2. Description of the Related Art Heretofore, it has been important to regulate a member fitted to a shaft with another member having a certain gap in order to rotate or slide. At this time, it was very difficult and difficult to regulate the gap to a required constant size. In the following, the present application will be described in its entirety by taking a bearing device for a motor as an example, but it is needless to say that the present invention is not limited to the embodiment described above, and other applications are possible within the scope of the gist.

In recent spindle motors for driving magnetic disk devices and the like, dynamic bearing motors have been used for the purpose of minimizing shaft runout and minimizing positioning errors of a magnetic head and a beam spot in order to improve recording density. Used. In digital information equipment, a scanner motor is used in an optical unit that converts a light image read by a CCD into digital image information and irradiates the drum, but higher speed and higher definition directly affect the performance of applications. Because it is the most important unit, a dynamic pressure bearing motor has been adopted.

As described above, in order to minimize shaft runout, which is a feature of the hydrodynamic bearing motor, the dimensional tolerance of each member and each gap of the hydrodynamic bearing device is finished with high precision. FIG. 9 is a schematic sectional view of the dynamic pressure bearing portion of the dynamic pressure bearing device. Dynamic pressure bearing 67
Are fixed above and below a shaft 50 having one end as a shaft reference end 51.
The thrust bearing 63, the second thrust bearing 52, and the journal bearing 58 having a journal bearing thickness 62 sandwiched between the thrust bearings 52 and 63, facing the outer diameter of the shaft 50, and mounted on the inner wall of the housing 57. Become.

A gap between a journal facing surface 59 of the journal bearing 58 facing the shaft 50 and a shaft outer diameter surface 69 of the shaft 50 is a journal gap 60. The journal end surface 61 (upper and lower surfaces) of the journal bearing 58 and the first thrust facing surface 6 of the first thrust bearing 63
4 is a first thrust gap 54a, and a gap between the second thrust bearing 52 and the second thrust facing surface 53 is a second thrust gap 54b.
The sum of a and 54b is the thrust gap 54.

The journal gap 60 and the thrust gap 54 are filled with a fluid 66 such as a magnetic fluid or a lubricating oil.
9, a journal dynamic pressure groove 90 for generating a dynamic pressure in the journal direction in the journal direction, and a thrust direction formed on one or both of the journal end face 61 or the two thrust facing faces 53, 64. A dynamic pressure is generated during rotation of the shaft 50 by a thrust dynamic pressure groove (not shown) for generating a dynamic pressure, and the shaft 50 can fly at high speed and rotate. The dynamic pressure grooves include a herringbone groove and a helical bone groove.

The dimensional accuracy of each of the journal gap 60 and the thrust gap 54 is required to be 10 ± 2 μm, and the primary finished thickness accuracy and external dimensional accuracy of each peripheral member constituting the gap are approximately ± 5 μm. It has become. In particular, in the case of the H-type dynamic pressure bearing member configuration as shown in FIG. 9, the thrust gap 54 is finished with high precision because the three-dimensional stacking accuracy of the respective thrust bearing thickness 56 and journal bearing thickness 62 is effective. Things are difficult.
Hereinafter, the dimensional accuracy of the thrust gap 54 is 10 ± 2μ.
A conventional method for realizing m will be described.

As a first method, as shown in FIG. 10, a first thrust bearing 63 is fixed to a fixed position of a shaft 50,
Next, the assembly a in which the journal bearing 58 is fitted into the shaft 50 and then the second thrust bearing 52 is fitted into the shaft 50 is added to the total thickness of the three members by adding a thickness of the thrust gap 54 of 10 μm as shown in FIG. The first thrust end face 65 and the second thrust end face 55, which are opposite to the thrust facing surfaces 53, 64 of the thrust bearings 52, 63, respectively, are disposed on the assembling jig A having the fixed portion 81 having the width 80 as the width.
The second thrust bearing 52 is joined and fixed to the shaft 50 in a state where the second thrust bearing 52 is pressed against the wall portions 82 at both ends in the longitudinal direction of the shaft 50 of the fixing portion 81, thereby forming a thrust gap 54.
Is formed.

In this method, the dimensional accuracy of the thrust gap 54 is ±
The thickness accuracy of each of the three members fitted into the shaft 50 for realizing 2 μm is required to be ± 0.5 μm or less, and cannot be achieved with the primary finished dimensional accuracy of ± 5 μm as described above. It is necessary to perform secondary processing and tertiary processing to achieve the above thickness accuracy.

As a second method, the assembly a is
A micrometer is added to the above-mentioned assembly jig A, and the width 81
Is slightly widened and placed on an assembling jig B (not shown) having a width of 81 ′. The second thrust bearing 52 is slid in the direction opposite to the journal bearing 58, and the amount of movement is read by a micrometer. There is a method of increasing the dimensional accuracy of the thrust gap 54.

[0011]

However, each of the above methods has the following problems. First, in the first method, the dimensional accuracy of the thickness processing finish of each member is strictly ± 0.5 μm or less, and although assembly is easy, it requires costly pre-processing by grinding and polishing each member, so it is not cost-effective. There was a problem.

In the second method, in order to maintain the dimensional accuracy of the thrust gap 54, assembly with good composite sliding accuracy such as reading accuracy of the micrometer, play amount of the moving amount, parallelism in the moving direction, etc. In addition to preparing a jig, it also takes time to maintain the sliding surface constantly in a smooth state and always clean the measurement terminal surface of the micrometer. It takes a long time to perform the fine adjustment even when adjusting, so that there is a problem that the mass productivity and the cost power are lacking.

When the thrust bearings 63 and 52 and the shaft 50 are joined by an adhesive using the above-described methods, for example, when the shaft 50 and the first thrust bearing 63 are joined together, When the adhesive is applied and the first thrust bearing 63 is inserted from the end face of the shaft 50 on the side where the first thrust bearing 63 is fixed, the adhesive protrudes into a portion where the thrust gap 54 is opposite to the insertion direction. In some cases, there is a problem that the thrust gap 54 is partially narrowed or closed. Similarly, when the adhesive is applied to the position pressed in the direction of the thrust gap 54, the same problem occurs in other joints.

An object of the present invention is to solve the above-mentioned problems and to provide a method for forming a specified gap size between shaft fitting members with high accuracy, ease, high mass productivity, and low cost.

[0015]

In order to achieve the above object, a method of forming a gap in a shaft fitting member according to a first aspect of the present invention forms a specified gap between a plurality of members fitted into a shaft. A first groove having a first depth and a second groove having a second depth shallower by the gap than the first groove, and the plurality of members are fitted therein. After inserting one end of the shaft into the first groove, the uppermost member is fixed to the shaft so that the gap between the plurality of members becomes zero, and then one end of the shaft is inserted into the second groove. In this state, by fixing the lowermost member to the shaft, a prescribed gap is formed between the plurality of members.

According to a second aspect of the present invention, there is provided a method of forming a gap in a shaft fitting member, comprising: a cylindrical shaft serving as a rotation shaft; a journal bearing driven to rotate or slide with respect to the shaft; First to regulate the thrust direction of the bearing
A gap formed between the first and second thrust bearings and the journal bearing, the first groove having a first depth, the first groove having a first depth, and the second thrust bearing. A second groove having a second depth shallower than the first groove by the gap, and after inserting one end of the shaft into which the journal bearing and the first and second thrust bearings are fitted, into the first groove; A second thrust bearing is fixed to the shaft so that a gap between the journal bearing and each of the first and second thrust bearings is zero. Then, after inserting one end of the shaft into the second groove, By fixing a first thrust bearing to the shaft, a prescribed gap is formed between the first and second thrust bearings and the front journal bearing.

Further, according to a third aspect of the present invention, in the method of forming a gap in a shaft fitting member, when each thrust bearing is fitted into the shaft and both are fixed with an adhesive, an adhesive to the shaft or each thrust bearing is used. The adhesive is extruded toward the end face of the shaft when viewed from the journal bearing.

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 to 5 are sectional views showing an embodiment of the present invention, and FIG. 6 is a flowchart showing an assembling procedure. As shown in FIG. 1, a shaft 50 is inserted into a first groove 2 having a first depth 3 formed in a first assembly jig 1.
Insert the shaft reference end 51 side
Is brought into contact with the groove bottom of the first groove 2. Next, the first thrust bearing 63 is fitted into the shaft 50, and the first thrust end face 65 is brought into contact with the upper surface of the first assembly jig 1. Next, the journal bearing 58 is fitted into the shaft 50, and one journal end surface 61 is brought into contact with the first thrust facing surface 64.

Next, an appropriate amount of the adhesive 4 is applied to the inner wall portion of the second thrust bore 68 of the second thrust bearing 52, the second thrust bearing 52 is fitted into the shaft 50, and the other journal end face 61 is formed. The state shown in FIG. 2 is obtained by bringing the shaft 50 and the second thrust bearing 52 into contact with the second thrust facing surface 53, curing the adhesive 4 and joining the shaft 50 and the second thrust bearing 52.
Thereby, each thrust bearing thickness 5 described in the prior art can be obtained.
A thrust gap 54, which will be described later, is formed with the total thickness of the sum of 6 and the journal bearing thickness 62 as a zero point (the gap between the members is zero). Also, a second thrust gap 54 is formed.
Since the adhesive 4 is extruded in the direction opposite to the thrust facing surface 53, it does not hinder the formation of the thrust gap 54.

Next, as shown in FIG. 3, the shaft 50 is removed from the first groove 2 to separate the first assembly jig 1 from the assembly.
Only the first thrust bearing 63 on the side is removed, and an appropriate amount of the adhesive 4 is applied to the inner wall of the first thrust bore 70.

Subsequently, as shown in FIG. 4, a second assembly jig having a second groove 6 of a second depth 5 formed shallower by the thrust gap 54 than the first depth 3 described above. 7, the first thrust end face 65 side of the first thrust bearing 63 is placed so that the opening of the second groove 6 and the first thrust bore 70 coincide with each other, and then the journal bearing 58 is fitted. Then, the shaft reference end 51 of the shaft 50 on which the second thrust bearing 52 is mounted is brought into contact with the groove bottom of the second groove 6 through the first thrust bore 70, and the adhesive 4 is cured. As shown in FIG. 5, the bearing portion 8 in which a gap between the journal bearing 58 and the second thrust bearing 52 becomes a thrust gap 54.
Get. As a result, the adhesive 4 is formed in a direction opposite to the first thrust facing surface 64 for forming the thrust gap 54 as described above.
Is extruded, so that it does not hinder the formation of the thrust gap 54.

Here, the dimensional accuracy of the first depth 3 and the second depth 5 is finished to about ± 0.5 μm, and the thrust is formed by forming the bearing 8 by the above-described assembly procedure. The thrust gap 54 can be formed irrespective of the thickness accuracy of each member such as the bearing thickness 56 and the journal bearing thickness 62.

FIGS. 7 and 8 are schematic sectional views showing another embodiment of the present invention. A shaft groove 10 is formed in the assembly jig 9, and a groove bottom 11 is formed from a lower portion of the shaft groove 10.
Are slidably mounted in the depth direction of the shaft groove 10. The groove bottom 11 is formed such that the first groove 2 is formed at a position indicated by a solid line shown in FIG. 7 and a second groove 6 is formed at a position indicated by a dotted line by a positioning means (not shown). Utilizing the difference in groove depth of the thrust gap 54
Can be formed.

In the assembling method shown in FIGS. 1 to 6, the first assembling jig 1 and the shaft 5 as shown in FIG.
0, the first thrust bearing 63 is once removed, and the adhesive 4 is applied to the inner wall of the first thrust bore 70, but without removing the shaft 50 from the first thrust bore 70 as shown in FIG. May be applied to a predetermined location. Further, by combining the methods shown in FIGS. 1 to 6 and FIGS. 7 and 8, it becomes possible to assemble without transferring an assembling jig.

[0025]

According to the method of forming a gap between shaft fitting members according to the present invention, a predetermined gap such as a thrust gap is determined by the total thickness of the shaft fitting member such as the total thickness obtained by adding the thickness of the thrust bearing and the thickness of the journal bearing. The dimensions are zero-adjusted, and then the positioning and assembly of the shaft fitting member is performed with the difference between the two groove depths as the specified gap size.
It can be obtained easily, inexpensively, and with high productivity. Further, since the upper and lower shaft fitting members such as the shaft and the thrust bearing are bonded and fixed in a procedure in which the adhesive does not protrude in the direction of the specified gap, the specified gap can be reliably formed.

[0026]

[Brief description of the drawings]

FIG. 1 is an assembled sectional view showing an embodiment of a gap forming method according to the present invention.

FIG. 2 is an assembled sectional view showing an embodiment of the gap forming method of the present invention.

FIG. 3 is an assembled sectional view showing an embodiment of the gap forming method of the present invention.

FIG. 4 is an assembled sectional view showing an embodiment of the gap forming method of the present invention.

FIG. 5 is an assembled sectional view showing an embodiment of the gap forming method of the present invention.

FIG. 6 is a flowchart illustrating an embodiment of a gap forming method according to the present invention.

FIG. 7 is a schematic sectional view showing another embodiment of the gap forming method of the present invention.

FIG. 8 is a schematic sectional view showing another embodiment of the gap forming method of the present invention.

FIG. 9 is a schematic sectional view of a bearing portion of the dynamic pressure bearing device.

FIG. 10 is a schematic sectional view showing a conventional gap forming method.

FIG. 11 is a schematic sectional view showing a conventional gap forming method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st assembly jig 2 1st groove 3 1st depth 4 Adhesive 5 2nd depth 6 2nd groove 7 2nd assembly jig 8 Bearing part 9 Assembly jig 10 Shaft groove 11 Groove bottom 50 Shaft 51 Shaft Reference End 52 Second Thrust Bearing 53 Second Thrust Opposing Surface 54 Thrust Gap 54a First Thrust Gap 54b Second Thrust Gap 55 Second Thrust End Face 56 Thrust Bearing Thickness 58 Journal Bearing 61 Journal End Face 62 Journal Shaft Thickness 63 First Thrust bearing 64 First thrust facing surface 65 First thrust end surface

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kazuo Shiba 6-11-12 Honcho, Tanashi-shi, Tokyo Citizen Watch Co., Ltd. Tanashi Factory (72) Inventor Toyoji Kanazawa 6-1-1, Honcho, Tanashi-shi, Tokyo No.12 Citizen Watch Co., Ltd. Tanashi Factory F term (reference) 3J102 AA08 BA03 BA19 CA16 CA17 CA20 GA02 GA03

Claims (3)

[Claims] 1. A gap forming method for forming a prescribed gap between a plurality of members fitted into a shaft, wherein a first groove having a first depth and a second groove shallower than the first groove by the gap. And a second groove having a depth of, and after inserting one end side of the shaft into which the plurality of members are fitted into the first groove, the uppermost member such that a gap between the plurality of members becomes zero. After fixing one end of the shaft into the second groove, and then fixing the lowermost member to the shaft in that state, a prescribed gap is formed between the plurality of members. A method of forming a gap between shaft fitting members. 2. A cylindrical shaft serving as a rotation shaft, a journal bearing which is driven to rotate or slide relative to the shaft, and first and second thrust bearings which regulate a thrust direction of the journal bearing. , The first and second
In a gap forming method for forming a predetermined gap between a thrust bearing and the journal bearing, a first groove having a first depth and a second depth shallower than the first groove by the gap are provided. After inserting one end side of the shaft into which the journal bearing and the first and second thrust bearings are fitted into the first groove, the journal bearing and the first and second thrust bearings are inserted.
A second thrust bearing is fixed to the shaft such that a gap between the thrust bearings is zero, and then, after inserting one end of the shaft into the second groove, the first thrust bearing is fixed to the shaft in that state. A clearance between the first and second thrust bearings and the front journal bearing, thereby forming a clearance between the shaft fitting members. 3. When each of the thrust bearings is fitted to the shaft and both are fixed with an adhesive, the application position of the adhesive to the shaft or each of the thrust bearings is viewed from the journal bearing. The method for forming a gap between shaft fitting members according to claim 2, wherein the adhesive is extruded in a direction toward an end face of the shaft.