JPH11159536A - Rotary structural body and related product using thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of oscillation and vibration of a rotary member due to defective precision of a ball bearing mounting part, to prevent the generation of rust of the rotary member and/or a supporting member consisting of a metallic member, and to effect manufacture with high efficiency. SOLUTION: By applying surface treatment coating on the surface, except a bearing mounting surface 14al, of a shaft 14, out gas or rust are prevented from occurring. The bearing mounting surface 14al for which surface precision is required ensures rotation precision so that a coating layer is prevented from formation due to masking or peeling.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a rotating member and / or a supporting member made of a metal member, which is capable of rotating a rotating member with respect to a supporting member via a ball bearing with high precision around a fixed rotation axis. It can also prevent the occurrence of rust etc. of the member,
Rotary structure and related products using the same, ie, spindle motor, recording disk drive using this spindle motor as recording disk drive means, and read / write for reading / writing information recorded on a recording disk equipped with this rotary structure The present invention relates to a pivot device for rotatably supporting a device.

[0002]

2. Description of the Prior Art FIGS. 4 and 5 are a plan view and a sectional view showing a hard disk drive as an example of a general recording disk drive.

[0003] This hard disk drive has a case 1
02 and 104, at least one recording disk 118 and this recording disk 1
A spindle motor 100 for rotationally driving the motor 18 and a pivot device 128 are housed. The spindle motor 100 has a motor shaft 106 fixed to the cases 102 and 104, a rotor hub 110 rotatably supported by the motor shaft 106 via a pair of ball bearings 108 and 109, and is attached to the rotor hub 110. At least one recording disk 118 is fixed to the outer peripheral surface of the rotor hub 110 of the spindle motor 100 by a clamp means 116 and includes a rotor magnet 112 and a stator 114 provided on the shaft 106 so as to face the rotor magnet 112. A pivot device 128 for rotating the recording disk 118 together with the rotor hub 110 rotatably supports a read / write unit 120 having a magnetic head 119 for reading and writing information recorded on the recording disk 118. , Composed of a rotating member 126 to the shaft 122 and the shaft 122 that is fixed to 104 is rotatably supported via a pair of bearings 124, 125.

In such a hard disk drive, in order to accurately read and write information recorded on the recording disk 118 by the magnetic head 119, it is necessary to maintain cleanliness in the hard disk drive.
With the recent trend toward higher capacity of recorded information and faster reading and writing of information, there has been a demand for a higher density of recording tracks on a recording disk and a shorter distance between a head and the recording disk. Ensuring cleanliness in the apparatus is becoming an increasingly important issue.

[0005] One of the factors that deteriorate the cleanliness described above is as follows.
There is scattering of rust and the like generated from members such as a metal shaft or a rotor used for a spindle motor and a pivot device. Conventionally, stainless steel, which has relatively high corrosion resistance, has been used to prevent the occurrence of rust and the like.However, even with this stainless steel, rust generation cannot be completely prevented, and passivation treatment is performed on stainless steel members. I have been.

[0006] Passivation treatment can be said to be an excellent surface treatment method in terms of rust prevention effect. For example, when passivation treatment is applied to a stainless steel material, a sulfur component or a sulfur compound which is a free-cutting component contained in the stainless steel material is used. Appear on the surface, deteriorating the cleanliness of the inside of the apparatus as so-called outgas, and causing problems such as corrosion of the magnetic head. For this reason, post-processing such as baking is necessary as post-processing for degassing, but this baking has caused a problem in that the passive bait portion collapses and rust or the like is generated from the collapsed portion. In addition, the post-treatment such as the baking treatment is a factor that hinders efficient production in terms of man-hours and time.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems in the prior art, and has as its object to provide a support member via a shaft center line of the support member and a ball bearing. The axis of the rotatable member rotatably supported by the motor coincides with the precision with relatively high accuracy, preventing runout, vibration, etc. of the rotatable member due to poor accuracy of the ball bearing mounting portion, and preventing the metal member from moving. An object of the present invention is to provide a rotating structure and a related product using the same, which can prevent the occurrence of rust or the like on the rotating member and / or the supporting member and can be manufactured efficiently.

[0008]

According to a first aspect of the present invention, there is provided a rotating structure, comprising: a rotating member; and a supporting member rotatably supporting the rotating member via at least one ball bearing. And / or a surface treatment coating is applied to a portion of the support member other than a bearing mounting portion to which the ball bearing is mounted.

As a raw material of the rotating member and / or the supporting member, it is preferable to use stainless steel from the viewpoint of material workability or rigidity. The surface treatment coating applied to the stainless steel rotating member and / or the supporting member is preferably a coating method that does not involve a post-treatment such as a baking treatment such as a passivation treatment and has a high rust prevention effect. This can be achieved by electroless nickel plating.

However, the electroless nickel-plated portion tends to have an error in the roundness and diameter of the plated surface, so that the bearing mounting portion for mounting a ball bearing requiring high surface accuracy is plated. It is preferable not to have a layer.

When the bearing mounting portion receives the inner ring of the ball bearing, the outer diameter of the bearing mounting portion is made larger than that of the other portion. When the bearing mounting portion receives the outer ring of the ball bearing, the inner diameter of the bearing mounting portion is changed. By forming a smaller diameter than the part and masking the bearing mounting part that has been subjected to surface precision processing in advance during plating, it is possible to prevent the plating layer from being formed,
The surface accuracy of the bearing mounting portion can be ensured.

As another means, when the bearing mounting portion receives the inner ring of the ball bearing, the outer diameter of the bearing mounting portion is made larger than that of the other portion. By making the inner diameter smaller than the other parts, a machining allowance is provided in the bearing mounting part, the rotating member and / or the entire supporting member is plated once, the plating layer is dried and solidified, and then separated by cutting or the like. It is also possible to determine the accuracy of the surface of the bearing mounting portion.

The rotating structure constructed as described above can be used as a rotor and a shaft of a spindle motor for rotationally driving a mounted recording disk in a recording disk drive which requires high cleanliness and rotational accuracy. it can.

Further, the rotary structure of the present invention is also used as a rotating member and a stationary member of a pivot device for rotatably supporting a reading / writing device for reading / writing information recorded on a recording disk in a recording disk drive. be able to.

Examples of the recording disk include a non-removable recording medium such as a hard disk and a removable recording medium such as a floppy disk.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS.

FIG. 1 schematically shows a surface treatment coating layer and a bearing mounting portion of a rotating structure according to the present invention. In this drawing, reference numeral 2 denotes a member such as a rotor or a shaft to which a surface treatment coating is applied, and reference numeral 4 denotes a coating layer formed by the surface treatment coating. 2a is a bearing mounting portion to which a ball bearing is mounted, and 2b is a bearing mounting surface on which precision processing has been performed. The coating layer 4 is formed to prevent rust of the member 2 made of iron or stainless steel or the like. However, since the coating layer forming portion is liable to cause an error in roundness and dimensional accuracy, the surface accuracy is low. It is preferable that the coating layer 4 is not formed on the bearing mounting surface 2b where is required.

In this rotary member, first, the bearing mounting portion 2a of the member 2 is formed to have a larger diameter than the other portions, and is processed in order to improve the surface accuracy and roundness of the bearing mounting surface 2b. After covering the bearing mounting surface 2b by means such as post-masking, a surface treatment coating such as electroless nickel plating is performed to form a coating layer 4 over the entire surface of the member 2. After the coating layer 4 is dried and solidified, if the masking is removed by means such as etching, a rotating structure having a rust-preventing effect while ensuring surface accuracy is completed.

Further, the entire surface of the member 2 is subjected to surface treatment coating without covering the surface of the bearing mounting surface 2b of the member 2 without masking or the like, and the coating layer 4 is dried and solidified. A similar rotating structure can be obtained when the surface layer is formed by peeling off the coating layer formed on the substrate.

It should be noted that the coating layer 4 for preventing rust does not exist on the bearing mounting surface 2b. However, the bearing mounting surface 2b is formed by the bearing outer ring and the adhesive interposed between the bearing outer ring at the time of mounting the bearing. Since it is completely covered, no rust or the like is generated.

FIG. 2 is a sectional view showing an embodiment of a spindle motor provided with a rotating structure according to the present invention.

The spindle motor 10 includes a bracket 12
Is rotatably supported via a shaft 14 made of iron or stainless steel fixed coaxially at the center of the shaft and a pair of ball bearings 16 and 17 mounted on a bearing mounting portion 14a provided on the shaft 14. A rotor hub 18 and a cylindrical yoke 2 formed of a magnetic material on an inner peripheral portion of the rotor hub 18.
1 and a stator 2 disposed at a position facing the rotor magnet 20.
Consists of two.

On the surface of the shaft 14 of the spindle motor 10, as in the case of FIG.
A coating layer formed by electroless nickel plating is formed on a portion other than the outer peripheral surface 14a1 of the bearing mounting portion 14a having a larger outer diameter than other portions provided on the shaft 14, thereby preventing rust of the shaft 14. . Also, the outer peripheral surface 14a1 of the bearing mounting portion 14a formed on the shaft 14 has an accuracy corresponding to the inner diameter of the inner rings 16a, 17a of the ball bearings 16, 17 so that the rotor hub 18 does not vibrate or run out during rotation. Well processed. FIG. 1 shows a method of forming the outer peripheral surface 14a1 of the bearing mounting portion 14a.
As described above.

FIG. 3 is a sectional view showing another embodiment of the spindle motor provided with the rotating structure of the present invention.

The spindle motor 30 in this embodiment
Is a shaft 34 coaxially fixed to the center of the bracket 32, and a pair of ball bearings 3 attached to the shaft 34.
6, a rotor hub 38 made of iron or stainless steel rotatably supported via 37, a rotor magnet 40 fixed to the inner peripheral portion of the rotor hub 38, and a shaft 34 between a pair of ball bearings 36, 37 And a stator 42 disposed opposite to the rotor magnet 40.

The rotor hub 38 of the spindle motor 30 has a radially inward portion from an upper bearing mounting portion 39 having a reduced inner diameter at an upper end portion and an inner peripheral portion of a bush 44 attached to the inner peripheral portion at the lower end of the rotor hub 38. The outer ring 36 of the pair of ball bearings 36 and 37 is formed at the projecting annular projection 44a.
a, 37a. On the surface of the rotor hub 38 of the spindle motor 30, a coating layer formed by electroless nickel plating is formed on a portion other than the inner peripheral surface 39 a of the upper bearing mounting portion 39 having a smaller inner diameter than the other portions. Prevents rust. In the bush 44 interposed between the inner peripheral portion of the lower end of the rotor hub 38 and the outer ring 37a of the lower ball bearing 37, a coating layer is similarly formed on the surface other than the inner peripheral surface 44a1 of the annular projection 44a having a smaller inner diameter than the other portions. Is formed. Further, an outer peripheral surface 39 of a bearing mounting portion 39 formed on the rotor hub 38.
The inner peripheral surface 44a1 of the annular projection 44a formed on the a and the bush 44 is adjusted to the outer diameter of the outer rings 36a, 37a of the ball bearings 36, 37 so that the rotor hub 18 does not vibrate or run out during rotation. Processed with high accuracy. The inner peripheral surface 39a of the upper bearing mounting portion 39 of the rotor hub 38 and the inner peripheral surface 4 of the annular projection 44a of the bush 44
The method of forming 4a1 is as described in FIG.

FIGS. 3 and 4 show an embodiment in which the rotating structure of the present invention is used only for the shaft as the fixed member or the rotor hub and the bush as the rotating member, respectively. It is clear that the same effect is obtained even when used simultaneously.

In the embodiment shown in FIGS. 2 and 3, the shaft is fixed to a bracket, and a so-called fixed shaft type spindle motor which rotatably supports a rotor hub via a ball bearing is used as an example of the present invention. Has been described, but as will be apparent to those skilled in the art, one end of the shaft is fixed to the rotor hub or both are integrally formed, and the shaft is rotatably supported via a ball bearing. Also in a shaft rotation type spindle motor, members such as a rotating shaft to which an inner ring of a ball bearing is fixed and a bearing housing or a sleeve to which an outer ring is fixed are configured similarly to the rotating structure in the present invention. The same excellent effects as those of the embodiment shown in FIGS. 2 and 3 can be provided.

Further, in the case where the rotary structure of the present invention is used in a pivot device for rotating and supporting a head for reading and writing information recorded on a recording disk in a recording disk drive device, the configuration in the embodiment of the spindle motor described above. This can be achieved by using the same stationary member and rotating body as in.

It should be noted that the vertical positional relationship in the above description of the embodiment is merely for convenience of description based on the drawings, and does not limit the actual use state and the like.

[0031]

According to the rotary structure of the present invention, since the rotary member and / or the support member are subjected to surface treatment coating and the ball bearing is directly mounted on the bearing mounting portion, the shaft center line of the support member and the ball bearing are mounted. The axis of the rotatable member rotatably supported by the support member is relatively accurately coincident with the rotatable member, thereby preventing runout, vibration, etc. of the rotatable member due to poor accuracy of the ball bearing mounting portion. In addition, the generation of rust or the like on the rotating member and / or the supporting member made of a metal member is prevented, and post-treatment such as baking is not required.

According to the spindle motor of the present invention, the rotor and the axis of the shaft located at the rotation axis of the rotor match with relatively high accuracy, and the rotor bearing due to the poor accuracy of the ball bearing mounting portion. Oscillation, vibration, and the like are prevented from occurring, and rust, etc., on the rotor and / or shaft made of a metal member is prevented, and post-treatment such as baking treatment is not required. .

According to the recording disk drive device provided with the spindle motor of the present invention, the rotational vibration and vibration of the rotor are prevented, and the generation of outgas from the rotor and / or the shaft of the spindle motor and the scattering of rust. Can be prevented, and since the cleanliness in the apparatus is maintained, it is possible to reliably read and write the information on the recording disk mounted on the rotor.

Further, by using the rotary structure of the present invention for a pivot device for rotatably supporting a read / write device for reading and writing information recorded on a recording disk in a recording disk drive, the rotary structure of the present invention described above is used. The same effect as when a spindle motor having a body is used can be obtained.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view schematically illustrating a distribution state of a coating agent on a member surface.

FIG. 2 is a half sectional view showing an embodiment of a spindle motor provided with a rotating structure of the present invention.

FIG. 3 is a half sectional view showing another embodiment of the spindle motor provided with the rotating structure of the present invention.

FIG. 4 is a plan view showing a general hard disk drive.

FIG. 5 is a sectional view of a general hard disk drive.

[Explanation of symbols]

 10, 30 Spindle motor 12, 32 Bracket 14, 34 Shaft 14a Bearing mounting portion 14a1 Outer peripheral surface 16, 17, 36, 37 Ball bearing 16a, 17a Inner ring 36a, 37a Outer ring 18, 38 Rotor hub 20, 40 Rotor magnet 21, Yoke 22, 42 Stator 39 Upper bearing mounting portion 39a Inner peripheral surface 44 Bush 44a Annular protrusion 44a1 Inner peripheral surface

Claims (10)

[Claims] 1. A rotary member and a support member rotatably supporting the rotary member via at least one ball bearing, excluding a bearing mounting portion to which the ball bearing of the rotary member and / or the support member is mounted. A rotating structure characterized in that a surface treatment coating is applied to a part thereof. 2. The rotating structure according to claim 1, wherein the rotating member and / or the supporting member are made of stainless steel. 3. The method according to claim 1, wherein said surface treatment coating is made by electroless nickel plating.
3. The rotating structure according to 1. 4. An outer diameter of the bearing mounting portion of the shaft receiving the inner race of the ball bearing is larger than an outer diameter of a portion of the shaft on which the surface treatment coating is applied. The rotating structure according to claim 1. 5. The rotary structure according to claim 1, wherein an inner diameter of said bearing mounting portion for receiving an outer ring of said ball bearing is smaller than an inner diameter of a portion to which said surface treatment coating is applied. . 6. The rotating structure according to claim 4, wherein the bearing mounting portion is prevented from adhering a coating agent during surface treatment coating by masking. 7. After the surface treatment coating is applied to the entire rotating member or support member, the bearing mounting portion having a larger outer diameter or a smaller inner diameter than other portions is used to obtain the accuracy of the bearing mounting portion. The rotating structure according to claim 4, wherein the coating layer is cut by the processing performed. 8. A spindle motor comprising a rotor, a rotor magnet attached to the rotor, a stator provided to face the rotor magnet, and a shaft located at the rotation axis of the rotor. A spindle motor comprising the rotary structure according to claim 1, 2, 3, 4, 5, 6, or 7 as the rotor and the shaft. 9. A hard disk drive comprising at least one recording disk, a head unit for reading and writing information recorded on the recording disk, and driving means for driving the recording disk to rotate. A recording disk drive, comprising: the drive means provided with the spindle motor according to claim 8. 10. A pivot device for rotatably supporting a read / write device for reading and writing information recorded on a recording disk mounted in a recording disk drive device having at least one recording disk, Claims 1, 2, 3, 4, 5, as a rotating body and a stationary member of the pivot device.
A pivot device comprising the rotating structure according to claim 6 or 7.