WO2002073774A1

WO2002073774A1 - Airtight structure of electronic device

Info

Publication number: WO2002073774A1
Application number: PCT/JP2001/001965
Authority: WO
Inventors: Keiichi Miyajima
Original assignee: Fujitsu Limited
Priority date: 2001-03-13
Filing date: 2001-03-13
Publication date: 2002-09-19

Abstract

An airtight structure of electronic device capable of increasing the airtightness of a magnetic disc device of such a type assembled by inserting a spindle motor stator yoke into a hole part formed in the base of a cabinet, comprising a spindle motor (10) having the stator yoke (12) and a rotor yoke (16), the stator yoke (12) comprising a peripheral projected part (26) made of elastic material installed on the lower surface of the upper stage part (20a) of a flange part (20) integrally with the upper stage port (20a), the base (14) comprising a lower stage part (14b) having a peripheral groove part (40) formed therein, wherein the lower stage part (20b) of the flange part (20) of the stator yoke (12) is inserted into the hole part (38) of the base (14), the upper stage part (20a) of the flange part (20) of the stator yoke (12) is disposed on the lower stage part (14b) of the base (14), and the peripheral projected part (26) is inserted into the peripheral groove part (40) so as to fix the stator yoke (12) to the base (14).

Description

Airtight structure of electronic equipment

The present invention relates to an airtight structure of an electronic device, and in particular, inserts a stator yoke of a spindle motor into a hole formed in a base of a housing, and engages a periphery of the stator yoke with a periphery of a hole of the base. The present invention relates to an airtight structure of a magnetic disk device in which an engaging portion is provided and the engaging portion is hermetically sealed by a seal portion. Background art

Electronic devices are designed in consideration of various points such as, for example, arranging related components in close proximity to sufficiently exert the function of the device, or reducing the external dimensions of the device as a whole. Each component is laid out and handled in a form in which each component is housed in a casing having a shape suitable for the layout. In this case, some electronic devices require a high degree of airtightness.

For example, in the case of the magnetic disk drive 1, as shown in FIG. 1, the rotating disk 1a is rotated by being urged by a spindle motor (not shown) to record information, and the rotating disk is urged by an actuator 1b. Information is exchanged between the heads 1c floating above 1a, and recording and reproduction are performed. In addition, in FIG. 1, reference numeral 2 indicates a base 2 that forms a housing. The separation between the rotating disk 1a and the head 1c is usually small, on the order of microns. In order to efficiently record and reproduce information on the rotating disk 1a, which is recorded at a higher density, the spacing between the rotating disk 1a and the head 1c must be even smaller than the micron order. Submicron level is required. As a result, the airtightness of the magnetic disk drive 1 decreases, and if dust or the like enters the inside of the drive from outside, the flying stability of the head 1c is impaired, and the head 1c and the rotating disk 1 There is a possibility that a head crash may occur which is damaged by contact with a.

Further, a decrease in the airtightness of the magnetic disk device 1 may cause various problems other than the above-described head crash. In such a magnetic disk drive, a good airtight structure is particularly essential. Hereinafter, among the hermetic structures of a conventional magnetic disk drive, the hermetic structure of the joint (engaging portion) between the spindle motor and the base of the housing will be described. When the spindle motor is driven, a pressure distribution lower than the atmospheric pressure is generated around the rotating motor inside the magnetic disk drive that is hermetically closed by the housing, so it is necessary to pay special attention to the airtight structure around the installed motor. There is.

By the way, in a conventional magnetic disk drive, there are two types of a structure for attaching a spinned motor to a housing, an integrated base type and a separated base type.

In the case of the former integrated base, as shown in FIG. 2, a rotor yoke (motor hub) 3a and a stator yoke (bracket) 3b, which are components of the spindle motor 3, are separately prepared. At this time, the stator yoke 3b is formed integrally with the base 2, and the rotor yoke 3a is attached to the stator yoke 3b when assembling the device. Note that, in FIG. 2 and FIG. 3 used in the following description, for convenience of description, the illustration of coils and the like is omitted, and the external shape of each member is indicated by hatching or the like instead of a complete cross-sectional view.

On the other hand, in the case of the latter base-separated type, as shown in FIG. 3, the spindle motor 3 is a motor separated from the base 2 in a state where the rotor yoke 3a and the stator yoke 3b, which are the component parts, are integrated. Prepared as a finished part. Then, the stator yoke 3 b is inserted into the hole 4 formed in the base 2, and the periphery 5 of the stator yoke 3 b is engaged with the periphery 6 of the hole 4 of the base 2 to form an engagement portion a. Then, the engagement part a is hermetically sealed by the O-ring 7. At this time, with the O-ring 7 attached to the outer periphery of the lower end of the stator yoke 3b, the O-ring 7 is positioned on the orbiting step (groove) 8 formed on the peripheral edge 6 of the base 2, and the O-ring 7 is positioned. The parts of the stator yoke 3 b at several places on the outer periphery of the attachment point and the part of the base 2 are fastened by the fastening member 9, and the O-ring 7 is elastically deformed by the pressing force, and the periphery of the stator yoke 3 b The airtightness is achieved by bringing the portion 5 and the peripheral portion 6 of the base 2 into close contact.

As is clear from Figs. 2 and 3, in both the former integrated base type and the latter separated base type, the lower surface of the stator yoke 3b and the lower surface of the base 2 are flush with each other. (Same surface) Alternatively, do not provide the stator yoke 3b on the base 2. The reason why the lower end of the stator yoke 3b is provided so as to protrude downward from the base 2 is to reduce the height of the entire apparatus.

In the case of the former base integrated type, since the stator yoke 3b is formed integrally with the base 2, there is no problem with the airtightness at the motor mounting portion. On the other hand, the manufacturing method in which the stator yoke 3b is formed integrally with the base 2 has a disadvantage that the manufacturing cost is higher than the latter motor-separated type.

For this reason, the latter base-separated type is being adopted from the viewpoint of manufacturing cost reduction rather than the former integrated base type.

However, in the base-separated type, as described above, the step portion 8 is formed in the peripheral portion 6 of the hole portion 4 of the base 2, so that the thickness t2 of the base 2 of the step portion 8 is thin. Then, if the load of the spindle motor 3 continues to be applied to the step portion 8 of the base 2 after assembling the device, the step portion 8 may bend downward and the hermeticity of the O-ring 7 may be impaired.

Then, the magnetic disk (not shown) to be mounted 1K For example, when the size of the magnetic disk is reduced from 3.5 inches to 2.5 inches, the original thickness t of the portion other than the step portion 8 of the base 2 due to the device design. 1 becomes thinner, for example, from about 2.5 mm to about 1.5 mm, and accordingly, the thickness t 2 of the base 2 of the stepped portion 8 becomes thinner by one layer. Such a problem of airtightness deterioration becomes more remarkable. In this case, it is conceivable that a circumferential groove is formed at a position of the base 2 away from the hole 4 without forming a step 8 at the peripheral edge 6 of the hole 4 of the base 2. Since it is not always easy to insert and install in the orbital groove with high positioning accuracy, sufficient airtightness may not be ensured. Disclosure of the invention

The present invention has been made in view of the above problems, and has a stator yoke inserted into a hole formed in a base of a housing, and a peripheral edge of the stator yoke is engaged with a peripheral edge of the hole of the base. An object of the present invention is to provide a good sealing structure of an electronic device in which an engaging portion is provided and the engaging portion is hermetically sealed.

To achieve the above objectives, the airtight structure of the electronic device of this effort should be The stator yoke of the motor is inserted into the formed hole, and the peripheral portion of the stator yoke is engaged with the peripheral portion of the hole of the base to form an engaging portion. In the hermetic structure of the electronic device thus airtight, the seal portion is made of an elastic material, and is located at a predetermined distance from the outer periphery of the hole portion, at a peripheral portion of the stator yoke or at a peripheral portion of the base. A peripheral convex portion integrally formed with at least one of the portions, wherein the peripheral convex portion is pressed into contact with a mating member to be engaged and deformed to hermetically seal the engaging portion. And

According to the above configuration of the present invention, it is not necessary to reduce the thickness of the end (outer perimeter) of the peripheral portion of the hole of the base, so that a good airtight structure of the engaging portion between the base and the stator yoke of the motor can be achieved. Obtainable.

The hermetic structure of the electronic device according to the present invention may be configured such that at least one of the stator yoke or the base is separated from the outer periphery of the hole by a predetermined distance in an assembled state.

A plurality of through-holes are formed at the position of the peripheral edge of one surface, and a concave or orbital groove-shaped mold is formed at a position corresponding to the through-hole, the through-hole having a large diameter. An elastic material is injected and molded using a lower mold having a tee and an upper mold having a concave cavity in which the diameter of the through hole is also large at a position corresponding to the through hole. The peripheral convex portion, an insertion portion connected to the peripheral convex portion and penetrating the through hole portion, and a dimension larger than the diameter of the through hole portion connected to the penetrating portion, And a convex or circumferentially projecting locking portion protrudingly provided on the surface on the opposite side to the above.

Here, the locking portion may be formed in the same shape as the orbital convex portion, and the diameter of the through-hole portion may be formed in a plurality of protrusions provided with slightly larger dimensions. . According to the above configuration of the present invention, the orbiting convex portion can be reliably formed integrally with the stator yoke, and can be formed with high positioning accuracy, so that the airtightness can be further improved.

Further, the hermetic structure of the electronic device of the present invention is characterized in that a circumferential groove into which the circumferential protrusion is inserted is formed in a mating member to be engaged.

According to the above configuration of the present invention, a large contact area between the orbiting convex portion and the base can be obtained, and airtightness can be achieved over a long portion of a path through which outside air enters the device. Therefore, the airtightness can be further improved.

The airtight structure of the electronic device according to the present invention is such that the electronic device is a magnetic disk device, and the motor is a spindle motor that urges and rotates a disk of the magnetic disk device. Can be suitably performed. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic perspective view of the magnetic disk drive with a cover removed.

FIG. 2 is a sectional view of a conventional base-integrated magnetic disk drive.

FIG. 3 is a sectional view of a conventional base-separated magnetic disk drive.

FIG. 4 is a plan view of a spindle motor and a base of the magnetic disk drive of the present invention.

FIG. 5 is a sectional view of the spindle motor and the base of the magnetic disk device of the present invention, taken along line VV in FIG.

FIG. 6 is a plan view showing only the upper part of the flange part of the stator yoke of the magnetic disk drive of the present invention.

FIG. 7 is a view for explaining a molding method by injecting an elastic material into the stator yoke of the present invention, and a cross section of the upper portion of the flange portion of FIG. 6 on the line VII-VII is arranged in a mold. It is a fragmentary sectional view showing a state.

FIG. 8 is a partial perspective view showing only the elastic members formed by the molding method of the present invention.

FIG. 9 is a perspective view of a spindle motor for explaining a method of attaching the spindle motor of the present invention to a base.

FIG. 10 is a sectional view showing a modification of the elastic member of the present invention.

FIG. 11 is a sectional view showing another modification of the elastic member of the present invention.

FIG. 12 is a view for explaining a state in which the base and the stator yoke are in close contact with each other due to deformation of the elastic member.

FIG. 13 is a partial cross-sectional view of a spindle motor and a base for explaining a first modification of the present invention.

FIG. 14 shows a spindle motor and a base for explaining a second modification of the present invention. It is a fragmentary sectional view of a case.

FIG. 15 is a partial sectional view of a spindle motor and a base for explaining a third modification of the present invention.

FIG. 16 is a partial sectional view of a spindle motor and a base for explaining a fourth modification of the present invention.

FIG. 17 is a partial cross-sectional view of a spindle motor and a base for explaining a fifth modification of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

A preferred embodiment of the present invention will be described below with reference to FIGS. 4 to 10 taking an airtight structure of a magnetic disk device as an example.

The configuration of the main part of the magnetic disk drive of the present invention is the same as that of the magnetic disk drive shown in the conventional example, so that illustration and description are omitted.

The magnetic disk drive of the present invention belongs to the separated base type described in the conventional example.

FIG. 4 is a plan view showing a state in which the spindle motor 10 is mounted on the base 14, and FIG. 5 is a cross-sectional view taken along line VV of FIG. The figure is shown.

The spindle motor 10 for rotating the recording disk (disk) 1 a has a stator yoke 12 and a rotor yoke 16.

The stator yoke 12 has a cylindrical portion 18, and an upper step portion 20 a and a lower step portion 20 which extend around the lower end of the cylindrical portion 18 in a stepwise manner in a direction orthogonal to the axis of the cylindrical portion 18. b, and a disk-shaped flange portion (peripheral portion) 20 made of b. A plurality of holes (through holes) 44 are formed in the flange portion 20. A plurality of sets of stator cores 22 and coils 24 are attached to the outer periphery of the cylindrical portion 18.

On the lower surface of the upper portion 20a of the flange portion 20 (the lower surface in FIG. 5), a circumferential protrusion 26 made of an elastic material is provided at a predetermined distance D1 from the center end. ing. The orbital protrusion 26 may be formed by attaching an annular elastic material to the lower surface of the upper portion 20a as an orbital protrusion, but in the present embodiment, the orbital protrusion 26 is formed as It is formed integrally with the upper portion 20a of the flange portion 20. How to do it Will be described later.

The rotor yoke 16 is erected on the bottom 28 and on the periphery of the bottom 28 (in FIG. 5, the rotor yoke is suspended). And a cylindrical portion 32 having a hollow portion 32a penetrating to the bottom portion 28. A plurality of magnets 34 are attached to the inner surface of the outer wall portion 30.

A plurality of bearings 36 are disposed inside the cylindrical portion 18 of the stator yoke 1 2, and the cylindrical portion 32 of the rotor yoke 16 is fitted inside the bearing 36, and the stator yoke 1 and the rotor yoke 1 are provided. 6 is an integrated spindle motor. The base 14, which forms a housing together with a lid (not shown) of the magnetic disk device, has a penetrating hole 38 formed therein, and the peripheral portion A of the hole 38 has an upper step 14 a and a lower step 14. and b. A circumferential groove portion 40 is formed in the lower portion 14b at a predetermined distance D2 that is the same as the predetermined distance D1 from the outer periphery of the hole 38. In addition, a plurality of female screw-shaped holes 42 penetrating therethrough are formed at equal intervals in the circumferential direction outside the orbiting groove 40.

In the assembled state, the lower portion 20 b of the flange portion 20 of the stator yoke 12 passes through the hole 38 of the base 14 and projects therefrom, thereby positioning the spindle motor 10 on the base 14. ing. An upper portion 20a of the flange portion 20 of the stator is disposed on a lower end portion 14b of the base 14, and an engaging portion is constituted by the lower portion 14b and the upper portion 20a.

Then, the orbital convex portion 26 is inserted into the orbital groove portion 40, the male screw 46 is inserted into the hole portion 42, and the stator yoke 12 is attached to the base 14 by screwing into the hole portion 4. Fixed. The orbital protrusion 26 is elastically deformed according to the shape of the orbital groove 26 by the tightening force of the screw, and adheres to the base 14 (see FIG. 12).

The lower surface of the male screw 46 is attached with a sheenor material 48 a made of a silver thin film, for example, made of a silver thin film, and the cylindrical portion 1 is also provided on the lower surface of the stator yoke 12. A seal member 48 b having a large dimension is attached to the hollow portion of the hollow portion 8, and the gap between the male screw 46 and the hole portion 42 is made airtight in the hollow portion of the cylindrical portion 18. The integrated structure of the orbital protrusion 26 and the flange 20 used in the airtight structure of the magnetic disk drive configured as described above will be further described with reference to FIGS. Will be explained.

Fig. 6 shows a plan view of the upper portion 20a of the flange portion 20 with other parts omitted, and Fig. 7 shows a cross-sectional view of a state in which the flange portion 20 is arranged in a mold to form an elastic member. FIG. 8 is a perspective view showing only the molded elastic member, and FIG. 9 is a perspective view showing the stator yoke 12 and the base 14 for explaining how to attach the stator yoke 12 to the base 14. FIG.

Stator yoke 12 has a plurality of through-holes 50 formed in upper part 20 a of flange 20. The stator yoke 12 is made up of an upper die (upper die) 54 having a slightly larger diameter than the through-hole portion 50 and a circular groove-shaped cavity portion 52 having a rectangular cross section. The lower die (lower die) 58, which has a circular groove-shaped cavity part 56 with a larger diameter than the part 50 and a semicircular cross-section, is sandwiched between the lower die 58 and an elastic material such as synthetic rubber. Pour into part 52 and mold.

Thus, the elastic member in which the orbital protrusion 26 having a semicircular cross-section and the engaging portion 60 having the same orbital shape are connected by a shaft portion (through portion) 62 which passes through the hole 50. 64 are formed integrally with the upper portion 20a.

Here, as described later, it is desirable that the orbital convex portion 26 be shaped so that the contact area with the base 14 can be as large as possible when pressed and deformed. The diamond (diamond) shown in FIG. 10 is also suitable. In addition, instead of the above-mentioned circular shape, the locking portion 60 may be a convex shape as shown in FIG. 11 using an upper die having a concave cavity.

The hermetic structure of the magnetic disk drive of the present invention configured as described above does not have the circular step 8 around the hole 4 unlike the conventional example in the lower part 14 b of the base 14. The lower peripheral portion 14b has the same thickness as the other portions without reducing the thickness of the peripheral portion on the center side, so that the engaging portion between the base 14 and the stator 12 of the spindle motor 10 is formed. A good airtight structure of A can be obtained.

Further, in the airtight structure of the magnetic disk device of the present invention, since the orbital convex portion 26 is formed integrally with the flange portion 20 of the stator yoke 12 by a molding method, the positioning of the orbital portion 26 is performed. Accuracy is good and airtightness can be ensured. In addition, as shown in FIG. 12, the orbital convex portion 26 is elastically deformed and closely adheres to the orbital groove portion 40. Therefore, the contact area between the orbital protrusion 26 and the base 14 can be increased, and the air can be airtight over a long part of the path (L 1 + L 2 + L 3) into which the outside air enters the device. .

Next, five modifications of the hermetic structure of the magnetic disk device of the present invention will be described below with reference to partial cross-sectional views of the pace 14 and the stator yoke 12 in FIGS. 13 to 17.

The first modified example shown in FIG. 13 has substantially the same structure as the hermetic structure of the magnetic disk drive of the present invention, except that the lower groove 14b is not formed in the lower portion 14b of the base 14, and The difference from the hermetic structure of the magnetic disk drive of the present invention is that the entire surface of the step portion 14b is formed flat.

In the first modified example, the processing of the base 14 is simple because the orbital groove is not formed in the lower portion 14 b of the base 14, and the central side peripheral portion of the lower portion 14 b Deflection is more reliably prevented.

The second modified example shown in FIG. 14 is a modification of the first modified example shown in FIG.

That is, the orbital protrusion 26 is formed on the lower portion 14 b of the base 14. The second modification can provide the same effect as the first modification.

In a third modified example shown in FIG. 15, the members forming the circumferential convex portion and the circumferential groove portion of the hermetic structure of the magnetic disk device of the present invention are arranged in reverse.

That is, the orbital protrusion 26 is formed in the lower portion 14 b of the base 14, and the orbital groove 40 is formed in the upper portion 20 a of the stator 12.

The third modification can provide the same effect as the hermetic structure of the magnetic disk drive of the present invention.

In the fourth modified example shown in FIG. 16, the orbital protrusion 26 is provided on the lower part 14 b and the base 14 of the base 14 and the upper part 20 a of the stator yoke 12 and the orbital groove is formed. I haven't.

The fourth modification can achieve more airtightness than the first modification. The fifth modification shown in FIG. 17 corresponds to the lower projections 14 b of the base 14 and the upper projection of the stator yoke 12 corresponding to the two orbiting projections 26 of the fourth modification. 2 0 a Each of them has a circumferential groove 40 formed thereon.

The fifth modified example can achieve more airtightness than the fourth modified _example.c

Claims

The scope of the claims

1. The stator yoke of the motor is inserted into a hole formed in the base of the housing, and the periphery of the stator yoke is engaged with the periphery of the hole of the base to form an engagement portion. In a hermetic structure of an electronic device in which a portion is hermetically sealed by a seal portion, the seal portion is made of an elastic material, and is located at a predetermined distance from an outer periphery of the hole portion. A peripheral portion formed integrally with at least one of the peripheral portions;

An airtight structure of an electronic device, wherein the orbiting convex portion is pressed against an engaging member to be engaged and deformed to make the engaging portion airtight.

2. The hermetic structure of an electronic device according to claim 1, wherein the orbital groove into which the orbital convex is inserted is formed in a mating member to be engaged.

3. In the assembled state, a plurality of through-holes are formed at a position of a peripheral edge of at least one surface of the stator yoke or the base which is separated from the outer periphery of the hole by a predetermined distance; The lower die having a circular groove-shaped cavity formed at a position corresponding to the diameter of the through-hole portion and having a size of a circular groove-like cavity. The diameter of the through-hole portion at a position corresponding to the through-hole portion is also reduced. An elastic material is injected and molded by using an upper mold having a concave cavity formed in a large dimension, and the circular convex portion is connected to the circular convex portion to penetrate the through hole. And a portion which is connected to the communicating portion, is formed to have a size larger than the diameter of the through hole portion, and is provided with a convex locking portion projecting from the surface opposite to the one surface. The airtight structure of the electronic device according to claim 1.

4. In the assembled state, a plurality of through-holes are formed at a position of a peripheral edge of at least one surface of the stator yoke or the base which is separated from an outer periphery of the hole by a predetermined distance; And a lower mold having a circumferential groove-shaped cavity formed at a position larger than the diameter of the through hole at the position corresponding to the through hole, and a large diameter of the through hole at the position corresponding to the through hole. An elastic material is injected and molded by using an upper mold having a circular groove-shaped cavity formed in the circular convex portion, a through portion connected to the circular convex portion and penetrating through the through-hole portion, And a diameter larger than the diameter of the through-hole portion connected to the communication portion, and provided with a circumferentially projecting locking portion projecting from the surface opposite to the one surface. The airtight structure of the electronic device according to claim 1.

5. The hermetic structure of the electronic device according to claim 1, wherein the electronic device B is a magnetic disk device, and the motor is a spindle motor for urging and rotating the disk of the magnetic disk device. . .