JP2906589B2 - Bearing for electronic equipment and method of manufacturing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a dynamic pressure type bearing used for a rotary drum such as a VTR.

[Summary of the Invention]

The present invention provides a bearing for an electronic device having a sleeve in a rotating body and a shaft inserted into the sleeve rotatably supported by a fluid, wherein the rotating body and the sleeve are integrally formed of an aluminum alloy, The surface facing the shaft is plated with a copper alloy, which is softer than the aluminum alloy, to improve the accuracy of the vertical axis and eccentricity of the rotating part, as well as the accuracy and durability of the bearing itself. This makes it possible to improve the performance.

The present invention also provides a bearing for an electronic device having a sleeve integrally formed of the same material in a rotating body and supporting a shaft inserted in the sleeve so as to be rotatable by a fluid. After the step of processing the surface facing the shaft to an inner diameter larger than a predetermined inner diameter, a step of plating the surface facing the shaft with a material softer than the material forming the rotating body to form the surface facing the shaft to a predetermined inner diameter By having the above, the shape accuracy of the inner circumference of the sleeve is improved, and the inner diameter accuracy is improved.

[Conventional technology]

In general, bearings used for rotating drums such as VTRs are so-called that the shaft is rotatably supported in the bearing by the pressure of the fluid due to demands such as good rotation accuracy of the rotating shaft and reduction of noise as much as possible. Dynamic pressure bearings are being used.

The conventional bearing is, as shown in FIG.
A sleeve (24) is provided in a rotary drum (23) including a lower drum (22) and a shaft (25) extending from the lower drum (22) is rotatably supported in the sleeve (24).

The upper drum (21) and the lower drum (22) are formed of an aluminum alloy, and the sleeve (24) is formed of a material softer than the aluminum alloy, for example, a copper alloy. The lower drum (22) is fixed together with the shaft (25), and the sleeve (24) is fixed to the upper drum (21) so as to rotate together with the upper drum (21).

[Problems to be solved by the invention]

However, in this type of conventional bearing, since the upper drum (21) and the sleeve (24) are provided separately, in order to rotate the upper drum (21) around the shaft (25) with high accuracy. To do so, the sleeve (24) must be fixed to the upper drum (21) in some way. As a fixing method, for example, bonding or press-fitting can be considered, but in the case of bonding, it is necessary to take into consideration the thickness of the adhesive layer, while in the case of press-fitting, the assembly accuracy is better than in the case of bonding. On the other hand, the sleeve (24) may be deformed at the time of press-fitting, and there is a disadvantage that the assembly itself becomes complicated.

As described above, when the sleeve (24) is fixed to the upper drum (21), assembling accuracy is an important issue. There is a disadvantage that it is affected.

Therefore, a method of manufacturing the upper drum (21) and the sleeve (24) as an integral type is conceivable. However, simply manufacturing the upper drum (21) and the sleeve (24) leaves a problem in terms of the material. That is, as a material of the upper drum (21), an aluminum alloy is considered to be good in terms of processing and the like, whereas the sleeve (24) is provided with a shaft (25) when the upper drum (21) stops rotating. ), It has been found that, for example, a copper alloy, which is softer than an aluminum alloy, is optimal in preventing the shaft (25) from being worn.

The present invention has been made in view of such a point, and an object of the present invention is to improve the accuracy of the vertical axis and the amount of eccentricity of a rotating part and to improve the accuracy and durability of the bearing itself. An object of the present invention is to provide a bearing for an electronic device and a method for manufacturing the same.

[Means for solving the problem]

The present invention has a sleeve (5) in a rotating body (upper drum) (2), and a shaft (4) inserted in the sleeve (5).
In a bearing for electronic equipment (1), which is rotatably supported by a fluid, the rotating body (2) and the sleeve (5) are integrally formed of an aluminum alloy, and a surface facing the shaft (4) is formed of an aluminum alloy. It is also formed by plating (a) with a copper alloy which is a soft material.

Further, the manufacturing method of the present invention has a sleeve (5) integrally formed of the same material in a rotating body (upper drum) (2), and a shaft (4) inserted in the sleeve (5) is rotated by a fluid. A method of manufacturing a bearing (1) for electronic equipment freely supported, comprising: processing a surface of a sleeve (5) facing a shaft (4) into an inner diameter larger than a predetermined inner diameter 1; ), A step of applying plating (a) with a material softer than the material constituting the rotating body (2) to form a predetermined inner diameter 1 on the surface facing the rotating body (2).

[Action]

According to the configuration of the present invention described above, since the rotating body (2) and the sleeve (5) are formed integrally, there is no need to consider the assembly accuracy of the rotating body (2) and the sleeve (5). It is possible to reduce the manufacturing cost and the manufacturing cost, and to improve the accuracy of the vertical rotation and the eccentricity of the rotating body (2).

Further, since the plating (a) is applied to the surface facing the shaft (4) with a copper alloy that is softer than the aluminum alloy forming the rotating body (2), the rotating body (2) and the shaft (4) are plated. )
Can prevent the abrasion of the shaft (4) caused by the contact, and can improve the durability and the rotational accuracy.

Further, after the surface of the sleeve (5) facing the shaft (4) is machined to an inner diameter larger than the predetermined inner diameter 1, the surface of the sleeve (5) facing the shaft (4) is softer than the material forming the rotating body (2). By performing plating (a) with a padding material, irregularities generated during processing can be filled with plating (a), and as a result, the shape accuracy of the inner surface of the sleeve (5) facing the shaft (4) can be reduced. Can be improved.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a schematic sectional view showing a rotary drum (A) for a VTR according to the present embodiment, particularly a bearing (1) thereof as a main part.

As shown, the rotary drum (A) is composed of an upper drum (2) and a lower drum (3), and has a sleeve portion (5) that supports a shaft (4) extending upward from the lower drum (3). It is formed integrally with the upper drum (2) with aluminum alloy,
Further, the surface of the sleeve portion (5) facing the axis (4) is plated with a material softer than the aluminum alloy constituting the upper drum (2), for example, a copper alloy (a). In the drawings, (6) shows a rotary transformer, (7) shows a rotor, (8) shows a stator, and (9) shows a magnetic head having a head chip (not shown) fixed at the tip. The pressing force on the shaft (4) generated by the rotation of the upper drum (2) of the fluid existing in the bearing (1), that is, the sleeve portion (5) causes the upper drum (2) to rotate. With a head (9) fixed to the upper drum (2) and running helically on the surface of the rotating drum (1) with respect to a magnetic tape (not shown). Perform recording and playback. V-shaped groove (10) provided on shaft (4)
Is for stably rotating the upper drum (2) with respect to the shaft (4). When the fluid flows along the groove (10), the V-shaped apex portion has high pressure, That is, the upper drum (2) is rotated with high precision as a so-called wedge of a metal bearing.

Next, the rotary drum according to the present example, in particular, the sleeve portion (5)
And the formation of copper alloy plating (a) will be described with reference to FIGS. 2 and 3. FIG.

Generally, the clearance (interval) between the shaft (4) and the inner diameter of the sleeve portion (5) is usually several μm to several tens of μm. This value depends on the specifications of the bearing (1).
Determine the performance of

Incidentally, the accuracy of the inner diameter of the sleeve portion (5) depends on the accuracy of the processing (drilling), and as shown in FIG. 2A, the maximum protruding portion (5a) formed by the processing has a reference dimension (indicated by a dashed line) l. 2B is a defective product. Usually, as shown in FIG. 2B, in the subsequent finishing process, the tip of the maximum protruding portion (5a) is at least on the reference dimension l. Eggplant

Thus, in this example, since the copper alloy plating (a) is applied to the inner surface of the sleeve part (5), as shown in FIG.
Thereafter, as shown in FIG. 3B, when the copper alloy plating (a) is applied, the plating layer (a) is used to adjust the inner diameter to a predetermined value. At this time, since the plating layer (a) is formed so as to fill in the irregularities of the inner periphery in the pre-processing shown in FIG. 3A, the shape accuracy of the inner periphery of the sleeve portion (5) is improved, and the inner diameter accuracy is good. Becomes

As described above, according to the present embodiment, since the upper drum (2) and the sleeve portion (5) are formed integrally, there is no need to consider the assembly accuracy of the upper drum (2) and the sleeve portion (5). In addition, easiness of manufacturing and cost reduction can be achieved. Further, the accuracy of the vertical axis and the amount of eccentricity of the upper drum (2) can be improved without being affected by the assembling accuracy.

Further, since the copper alloy plating (a) is applied to the surface of the sleeve portion (2) facing the shaft (4), the shaft (4) generated when the upper drum (2) comes into contact with the shaft (4). ) Can be prevented, and the durability of the bearing (1) itself and the rotation accuracy can be improved. Then, the surface of the sleeve (5) facing the shaft (4) is processed into an inner diameter larger than the desired inner diameter 1, and then the copper alloy plating (a) is performed to form the inner surface at the desired inner diameter 1. Therefore, the sleeve (5) Inner surface accuracy can be improved.

In the above embodiment, an example in which the lower drum (3) is fixed and the upper drum (2) rotates is shown. However, the present invention is also applicable to a rotating drum of the opposite type or a rotating drum in which only a head disk rotates. is there.

〔The invention's effect〕

ADVANTAGE OF THE INVENTION According to the bearing for electronic devices which concerns on this invention, while being able to improve the precision of the axis perpendicularity and eccentricity of a rotating part, the rotation precision and durability of a bearing itself can be improved.

Further, according to the method of manufacturing a bearing for an electronic device according to the present invention, it is possible to improve the shape accuracy of the inner surface of the rotating portion facing the shaft and obtain a good inner diameter accuracy.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a main part showing a configuration of a bearing according to the present embodiment, FIG. 2 is a process diagram showing a normal processing method, FIG. FIG. 4 is a schematic sectional view of a main part showing a conventional example. (A) is a rotating drum, (1) is a bearing, (2) is an upper drum, (3) is a lower drum, (4) is a shaft, (5) is a sleeve portion, and (a) is a plating layer.

Claims (2)

(57) [Claims] 1. A bearing for an electronic device having a sleeve in a rotating body and rotatably supporting a shaft inserted in the sleeve by a fluid, wherein the rotating body and the sleeve are integrally formed of an aluminum alloy. A bearing for electronic equipment, wherein a surface facing the shaft is plated with a copper alloy that is softer than the aluminum alloy. 2. A method for manufacturing a bearing for an electronic device, comprising a sleeve integrally formed of the same material in a rotating body, wherein a shaft inserted into the sleeve is rotatably supported by a fluid. After the step of processing the surface of the sleeve facing the shaft to an inner diameter larger than a predetermined inner diameter, the surface facing the shaft is plated with a material softer than the material constituting the rotating body to form the predetermined inner diameter. And producing the bearing for electronic equipment.