Hard disk drives (hereinafter, HDDS) most common as data storage means of computers each have the structure that a single magnetic disk or plural disk platters of magnetic disk are coaxially arranged on a shaft, and are driven by a spindle motor. A magnetic head provided with facing the above-described magnetic disk read and writes data, and this magnetic head is driven by an actuator, that is, generally, a voice coil motor (hereinafter, a VCM). The above-described magnetic disk, magnetic head, and actuator are contained in an enclosure called a disk enclosure. The disk enclosure consists of, for example, a shallow box-like base made of an aluminum alloy, and a top cover sealing an opening of the base. A gasket is provided in the circumference of the top cover facing the base. Hence, by assembling the base and top cover so that this gasket may be pressed to the edge side of the peripheral wall of the base, the inside of the disk enclosure can be hermetically sealed.
In the disk enclosure, temperature rises under the influence of the magnetic disk rotation and the like. Here, it is assumed that air in the disk enclosure that expands in connection with the temperature rise pushes the gasket aside and leaks outside. It is supposed that, if the temperature in the disk enclosure lowers, the air in the disk enclosure is shrunk, and now, on the contrary, air enters into the disk enclosure from the outside. At this time, if dust, vaporized organic substances, or vaporized inorganic substances enter into the disk enclosure with the air entering, the dust, above-described organic substances, or inorganic substances that are solidified collide against the magnetic head at the time of using the HDD to damage the magnetic head or magnetic disk. In order to prevent such entry of dust into the disk enclosure, a filter is provided in a top cover or a base in an actual HDD. This filter is called a breather filter. While becoming a passage for circulating air with the outside in connection with dilatation and contraction of the air in the disk enclosure caused by the temperature rise and fall, the filter reduces the entry of the dust, vaporized organic substances, or inorganic substances from the outside below such an amount that apparatus performance is not affected.
A conventional breather filter will be described with referring to drawings. In addition, the breather filter will be described in the case where it is attached to a top cover, although there are a case where it is attached to a top cover and a case where it is attached to a base.
FIG. 13 is a plan showing the back face of a top cover 100. Here, it is assumed that, at the top cover 100, a face exposed to the outside at the time of constituting the disk enclosure is called a front face and a face facing the inside of the disk enclosure and opposite to a base is called a back face. A gasket 101 for acquiring the hermeticity of the disk enclosure is stuck on the back face of the top cover 100 at the circumference thereof. Moreover, the breather filter 102 is stuck on the back face of the top cover 100 by double-sided adhesive tape. FIG. 13 also shows a perspective view of a breather filter 102 as well. In addition, the breather filter 102 shown in FIG. 13 is shown with a face, which is stuck on the top cover 100, being upward.
FIG. 14 is an assembly view of the breather filter 102. In addition, FIG. 14 shows the breather filter 102 with turning down the face stuck on the top cover 100. As shown in FIG. 14, the breather filter 102 mainly consists of a filter case 103, a filter body 104 contained in the filter case 103, and a permeable film 105 covering a surface of the filter body 104. In addition, FIG. 15A shows a front face of the filter case 103 and FIG. 15B shows a back face thereof.
In FIGS. 14, 15A, and 15B, the filter case 103 consists of a circular bottom wall 103a and peripheral wall 103b standing up from the circumference of the bottom wall 103a. A ventilation slot 103a1 is formed in the front face of the bottom wall 103a, and the ventilation slot 103a2 is formed in the back face. In addition, it is assumed that the front face of the bottom wall 103a in the filter case 103 means a lower face shown in a central portion of FIG. 14, and, the back face means an upper face shown in the central portion of FIG. 14. The ventilation slot 103a1 formed in the front face of the bottom wall 103a is a circular slot that starts from the center of the bottom wall 103a and stops at a ventilation hole 103a3 feeding through the bottom wall 103a. The ventilation slot 103a2 formed in the back face of the bottom wall 103a starts from the ventilation hole 103a3 and stops at the center of the bottom wall 103a. Thus, the ventilation slot 103a1 and the ventilation slot 103a2 communicate through the ventilation hole 103a3.
Double-sided adhesive tape 106 is stuck on the front face of the bottom wall 103a of the filter case 103, and double-sided adhesive tape 107 is stuck on the back face thereof. Therefore, the ventilation slot 103a1 forms a closed space with the double-sided adhesive tape 106, and the ventilation slot 103a2 forms a closed space with the double-sided adhesive tape 107. However, as shown in FIG. 14, since through holes 106a and 107a are formed in the centers of the double-sided adhesive tape 106 and the double-sided adhesive tape 107, parts corresponding to these holes communicate with the outside.
The filter body 104 is contained in the filter case 103. At this time, the filter body 104 is stuck and fixed by the double-sided adhesive tape 107 stuck on the back face of the bottom wall 103a. However, the fixing of the filter body 104 is not limited to the double-sided adhesive tape 107, but it is possible to use a mechanical constraint by a protrusion by providing the protrusion such as a rib in the filter case 103. The permeable film 105 is stuck on the upper face of the filter body 104 shown in a central portion of FIG. 14, and the breather filter 102 is united in one piece in this way.
The breather filter 102 is stuck on the top cover 100 through the double-sided adhesive tape 106 stuck on the front face of the bottom wall 103a. These conditions are shown in FIGS. 16 and 17. That is, a fresh air hole 100a formed in the top cover 100, the through hole 106a of the double-sided adhesive tape 106, and the breather filter 102 are centered, and the breather filter 102 is fixed to the top cover 100 by the double-sided adhesive tape 106.
When the air in the disk enclosure expands, air flows out to the outside in the following paths. That is, the air in the disk enclosure sequentially passes the permeability film 105, filter body 104, through hole 107a of the double-sided adhesive tape 107, the ventilation slot 103a2, ventilation hole 103a3, ventilation slot 103a1, through hole 106a of the double-sided adhesive tape 106, and the fresh air hole 100a of the top cover 100, and flows out to the outside. On the other hand, when the temperature in the disk enclosure lowers and fresh air flows into the disk enclosure, the fresh air sequentially passes the fresh air hole 100a of the top cover 100, through hole 106a of the double-sided adhesive tape 106, ventilation slot 103a1, ventilation hole 103a3, ventilation slot 103a2, through hole 107a of the double-sided adhesive tape 107, filter body 104, and permeable film 105. Even if dust, and vaporized organic substances or vaporized inorganic substances are mixed with the air flowing in, the air passes the filter body 104, whose principal component is activated carbon, and the permeable film 105. Hence, it is possible to reduce the entry of dust into the disk enclosure to a minute amount in such degree that the dust does not affect the apparatus performance.
Conventionally, the breather filter 102 is attached to the top cover 100 by manual operation. However, the top cover 100 may be assembled to a base without the breather filter 102 being attached. It is not easy to confirm whether the breather filter 102 has been attached to the top cover 100 after the top cover 100 and the base are assembled. Although there is also a method of confirming the presence of the breather filter 102 from fresh air hole 100a formed in the top cover 100, it does not become an exact confirmation method because of the fresh air hole 100a having only small diameter.
Moreover, the adhesion by the double-sided adhesive tape 107 may be insufficient even though the breather filter 102 has been attached to the top cover 100. In that case also, conventionally, it is not easy to confirm it.
Then, a subject of the present invention is to provide a method for making it possible to easily confirm whether the breather filter 102 is attached even after the top cover 100 is assembled to the base.
Furthermore, another subject of the present invention is to provide a method for making it possible to easily confirm whether the breather filter 102 is adequately attached to the top cover 100 even after the top cover 100 is assembled to the base.