JPH06251514A - Recorder - Google Patents

Abstract

PURPOSE:To provide a recorder which is small in the number of constituting members, can be easily assembled and is drastically reduced in production cost. CONSTITUTION:This recorder is provided with a recording medium in a case 10, a magnetic circuit part and an actuator consisting of an oscillatable arm 5 having a moving coil. A holding member 11 and posts existing near both side parts of this holding member 11 are respectively erected on the inside surface of this case 10 and these members are integrally formed of a thermoplastic resin material. A permanent magnet assembly formed of a permanent magnet 3 which is magnetized in a thickness direction and is formed to a flat planar shape and a lower yoke 19 which consists of a ferromagnetic material attracted to the rear surface of this permanent magnet 3 is integrally fixed to the case 10 so as to be embraced by the holding member 11 at the time of molding the case. An upper yoke 18 formed to include the permanent magnet 3 within the contour projected on the plane by the ferromagnetic material is fixed to the posts apart a spacing from the surface of the permanent magnet 3, by which the magnetic circuit part is constituted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording device such as a magnetic disk device, and more particularly to a thin recording device having an actuator which swingably supports an arm having a recording / reproducing head. The present invention relates to an improved product for cost reduction.

[0002]

2. Description of the Related Art FIG. 4 is a plan view of an essential part of a fragmentary crushing apparatus showing an example of a conventional magnetic disk device, and FIG. In FIGS. 4 and 5, 21, 2
Reference numerals 2 and 3 denote a case and a cover, which are made of a non-magnetic material such as an aluminum alloy and have a rectangular parallelepiped shape. In the case 21, a plurality of magnetic disks 24 are attached to a spindle 23 of a drive motor (not shown).
Are rotatably provided at a predetermined interval. Reference numeral 25 denotes an oscillating actuator, which has a magnetic head 26 facing the magnetic disk 24 at one end and a magnetic circuit unit 2 at the other end.
The arm 5 having the movable coil 6 facing the support shaft 7
It is configured to be rotatable or swingable via.

Next, reference numeral 1 denotes a yoke, which is made of a ferromagnetic material such as soft iron in a flat plate shape, and is provided so as to face each other via a pillar 2 provided at an end portion. 3 is a permanent magnet,
Formed in a substantially trapezoidal flat plate shape, magnetized in the thickness direction,
The yoke 1 is fixed to the surface of the lower yoke 1 so that the N and S magnetic poles appear on the surface, and the magnetic gap 4 is formed on the surface. The flat movable coil 6 fixed to one end of the arm 5 is
It is arranged so as to be located in the magnetic gap 4 formed by the permanent magnet 3.

When a signal current is applied to the movable coil 6 with the above-described structure, a driving force around the support shaft 7 acts on the movable coil 6 according to Fleming's left-hand rule, and the arm 5 is moved.
The magnetic head 26 provided at the end of the arm 5 can be positioned on a predetermined recording track on the magnetic disk 24 by rotating or swinging. The switching of the swinging direction is performed by reversing the direction of the current flowing through the movable coil 6.

FIG. 6 is an exploded perspective view of the components of the magnetic circuit unit 27 shown in FIGS. 4 and 5, and the same parts are designated by the same reference numerals as those shown in FIGS. 4 and 5.
In FIG. 6, reference numeral 9 is a positioning pin, which is provided on the lower yoke 1 and contacts the outer edge portion of the permanent magnet 3 so that the permanent magnet 3 can be fixed at a predetermined position.

[0006]

In assembling the magnetic circuit as described above, after processing the respective constituent members, first, as shown in FIG. 6, the positioning pin 9 is first mounted at a predetermined position, and then permanently. The magnet 3 is fixed to the yoke 1 with an adhesive. In this case, a treatment of heating and drying is required to cure the adhesive, and the fixing work of the permanent magnet 3 requires time and man-hours, resulting in a problem of high cost. Further, when the adhesive is dried by heating, harmful outgas may be generated from the adhesive, which may pollute the environment.

Next, after the permanent magnet 3 is fixed to the yoke 1, the support pillar 2 is fixed, the upper yoke 1 is mounted on the support pillar 2 and fixed by the setscrew 2a. Due to screwing and / or caulking, the percentage of manual work is high. Therefore, time and man-hours are increased, which causes a high cost.

On the other hand, in recent years, for example, magnetic disk devices provided with this type of oscillating actuator have been increasingly demanded to be thin and low in cost. However, the assembly cost is high and the above requirements cannot be satisfied.

The present invention solves the above-mentioned problems existing in the prior art, provides a small number of constituent members, facilitates assembly, and can significantly reduce the manufacturing cost, for example, a magnetic disk device. The purpose is to do.

[0010]

In order to achieve the above object, in the present invention, a case made of a non-magnetic material is provided so as to face a recording medium rotatably provided via a drive motor. A magnetic circuit part formed by fixing a permanent magnet to at least one of the pair of yokes, and a movable head facing the magnetic circuit part at one end and a recording head facing the recording medium, and a supporting shaft. In a recording apparatus including an arm formed to be swingable via a holding member, a holding member and columns located near both sides of the holding member are erected on the inner surface of the case, and these members are made of a thermoplastic resin material. A permanent magnet assembly that is integrally formed by magnetizing in the thickness direction and is formed in a flat plate shape, and a lower yoke made of a ferromagnetic material that is attracted to the back surface of the permanent magnet. The body is integrally fixed so as to be held by the holding member when the case is molded, and the upper yoke is formed by a ferromagnetic material so that the permanent magnet can be included in the contour projected onto the plane. The technical means of forming a magnetic circuit unit by being fixed to the pillar via a surface and a gap is adopted.

In the present invention, since the permanent magnet as a constituent member has a limited thickness, it cannot have a high operating point. Therefore, it is preferable to use a rare earth magnet having a large coercive force. Further, in recent years, since further thinning and higher performance are required, in order to secure a high magnetic flux density in the magnetic gap, R-Fe-B-based (R: Y, Nd, etc. rare earth element It is more preferable to use one or more permanent magnets.

Next, as the thermoplastic resin material in the present invention, for example, known resins such as polyphenylene sulfide resin, polybutylene terephthalate resin, polyamide resin, polyimide resin, polyamideimide resin, polyester resin (preferably heat resistance Resin) can be used.

Among the above resins, the longitudinal elastic modulus (measurement method:
Those having an ASTM D-638) of 10 × 10 ⁴ kg / cm ² or more (preferably 13 × 10 ⁴ kg / cm ² or more) are preferable. In particular, it is preferable to use, as the thermoplastic resin, a liquid crystalline polyester resin (polyester having a rigid straight chain in the main chain) which is a kind of liquid crystal polymer (which exhibits liquid crystallinity in a molten state).

The liquid crystalline polyester resin includes (a) a copolymer of parahydroxybenzoic acid and polyethylene terephthalate, (b) a copolymer of poly-p-hydroxybenzoate and an aromatic dicarboxylic acid, and an aromatic diol, ( c)
Although there are those having various basic compositions such as copolymers of poly-p-hydroxybenzoate and naphthoic acid, wholly aromatic compounds (b) and (c) are preferable in terms of strength and elastic modulus, The thing of (c) is more preferable. In particular, in the wholly aromatic polyester resin (c), since the rigid molecular chains are oriented in the flow direction during molding, the longitudinal elastic modulus in that direction is large, and in addition, it has good vibration absorption characteristics and a linear expansion coefficient. It has the advantage of being small (close to a metallic material).

When a liquid crystal polymer is molded at a liquid crystal state temperature lower than the complete melting temperature, it has high fluidity and facilitates molding. Especially the longitudinal elastic modulus (tensile elastic modulus) is 16 × 10 ⁴ kg /
It is advisable to use a liquid crystal polymer of cm ² or more. A specific example of such a liquid crystal polymer is Vectra A130 (1) which is a wholly aromatic thermotropic liquid crystalline polyester.
8 × 10 ⁴ ) (Unit: kg / cm ² , the same applies below), C130
(16 × 10 ⁴ ), A230 (30 × 10 ⁴ ), B23
0 (38 x 10 ⁴ ), A410 (21 x 10 ⁴ ), A4
22 (18 × 10 ⁴ ), C400 (17 × 10 ⁴ ), A
540 (16 x 10 ⁴ ) (above Celanese), XYD
AR RC-210 (16.2 x 10 ⁴ ), G-43C (1
6.1 × 10 ⁴ ) (above Dartco) and the like.

Incidentally, the longitudinal elastic modulus is steel: 220 × 10 ⁴ ,
Aluminum: 68 × 10 ⁴ , methacrylic resin: 4.2
X10 ⁴ , polystyrene resin: 3.2 to 3.6 x 10 ⁴ , polyphenylene sulfide resin: 10 x 10 ⁴ (both units are kg / cm ² ), which is larger than the use of ordinary thermoplastic resins. The rigidity can be obtained. Further, as the liquid crystal polymer, in order to improve mechanical strength, heat resistance and the like, one to which a filler such as glass fiber or carbon fiber is added can be used. Addition amount is 10
50% by weight is desirable, and more preferably 20-40% by weight.

Further, in the present invention, the above-mentioned thermoplastic resin is used.
Flexural modulus as fat (Measurement method: ASTM D-792)
Is 13 × 10^Fourkg / cm²The above can also be used effectively
It Examples of such a resin include the above-mentioned Vectra A.
130 (15 x 10^Four) (Unit is kg / cm², The same below
), C130 (14 x 10)^Four), A230 (29 x 1
0^Four), B230 (36 × 10^Four), A410 (18 x
10^Four), A422 (17 × 10^Four), A540 (14
× 10^Four), XYDAR RC-210 (13.6 × 1)
0 ^Four), G-43C (14.9 × 10^Four) And Ryton R
-4 (14 x 10^Four) (Phillips Oil), DIC / P
PS FZ-1140 (14 x 10^Four), ASAHI
PPS RG-40JA (14.4 x 10^Four) (Asahi Glass),
Fortron 1140A1 (13 x 10^Four) (Polyplastic
Sticks), GS-40 (15 x 10)^Four), G-10
(20 x 10^Four), G-6 (18 × 10^Four), G-4F
(14 x 10 ^Four), FC-5 (16 × 10^Four) (Above East
Saw Sustil) and other polyphenylene sulphies
Do and the like.

[0018]

With the above construction, the number of constituent members can be reduced, and since most of the constituent members are integrally molded, the assembling work is facilitated and the manufacturing cost can be greatly reduced. .

[0019]

1 is an exploded perspective view of a main part of a magnetic circuit according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of the main part of an embodiment of the present invention, and FIG. FIG. 7 is a partial cross-sectional view of an essential part taken along the line B in FIG.
The same reference numerals are used. 1 to 3, 1
Reference numeral 0 denotes a case, on the inner surface of which a holding member 11 for integrally holding a support 2 and a permanent magnet assembly 13 formed as will be described later is integrally projected, and a support shaft 16 fixed to the arm 5 is provided. The bearing 17 supporting the lower end is embedded and held.

In order to integrally form each of the above-mentioned components and to hold the permanent magnet assembly 13 integrally by the holding member 11, an injection molding die is used, and the molding space is filled with, for example, glass fiber. The heated melt of the polyphenylene sulfide resin in 1 above may be injected, cooled and solidified, and then taken out from the molding space. If the permanent magnet assembly 13 is inserted into a predetermined portion of the injection molding die before molding, the holding member 11 is formed by the injection of the heated melt, and at the same time, the permanent magnet assembly 13 is made permanent. The magnet assembly 13 is held and fixed. By inserting the bearing 17 into a predetermined portion in the mold, the case 10 is molded, and at the same time, the bearing 17 is integrally embedded in a predetermined position in the case 10.

Next, the permanent magnet 3 which constitutes the permanent magnet assembly 13 is formed into a substantially fan-shaped flat plate shape by using, for example, an Nd-Fe-B type magnet material, magnetized in the thickness direction, and N, S is formed on the surface.
It is configured so that the magnetic pole appears. When manufacturing such a permanent magnet 3, two permanent magnets may be joined together by a broken line portion to be integrated. Next, the lower yoke 19 is formed of a ferromagnetic material such as soft iron into a flat plate shape having an outer contour corresponding to the outer contour of the permanent magnet 3, and the lower yoke 19 is attracted to the back surface of the permanent magnet 3 to be attached to the permanent magnet assembly 13. Make up.

Reference numeral 14 denotes an upper yoke, which is formed of a ferromagnetic material similar to that of the lower yoke 19 into a pseudo-triangular flat plate shape, and has a mounting hole 15 at the end and a support shaft 1 for the arm 7.
A bearing 18 for supporting the upper end portion of 6 is provided. The upper yoke 14 is formed so that the permanent magnet 3 can be included in the contour projected onto the plane. 2a is a set screw.

In the case of assembling a magnetic circuit with the above-described structure, the constituent members are integrally provided, and the permanent magnet assembly 13 is integrally held and held in the holding member 11. The yoke 14 may be placed and fixed by the set screw 2a.

In the present embodiment, an example was described in which the peripheral edge of the holding member 11 integrally provided on the case 10 was formed continuously, but it may be formed discontinuously or in the form of a plurality of protrusions. Are the same, and in short, it suffices to have a function of holding and fixing the permanent magnet assembly 13. Further, as a means for fixing the upper yoke 14 to the column 2, not only the set screw 2a but also a rivet-like one is driven,
Alternatively, it may be press-fitted and fastened. Further, although the actuator for the magnetic head has been described in the present embodiment, the function member to be provided at one end of the arm is not limited to the magnetic head, but the optical head or the like has the same operation.

[0025]

Since the present invention has the structure and operation as described above, the number of constituent members can be significantly reduced by integrally molding most of the constituent members of the magnetic circuit of the actuator. Assembling work is facilitated, and productivity can be significantly improved, resulting in a significant reduction in manufacturing cost. Furthermore, by integrating most of the constituent members, there is an effect that the entire recording device such as a magnetic disk device can be made smaller and thinner.

[Brief description of drawings]

FIG. 1 is a perspective view of a main part of a magnetic circuit according to an embodiment of the present invention, showing constituent members in an exploded manner.

FIG. 2 is a sectional view of an essential part showing an embodiment of the present invention.

3 is a partial cross-sectional view of a main part of the BB line in FIG.

FIG. 4 is a plan view of a partial crushing essential part showing an example of a conventional magnetic disk device.

5 is a partially sectional enlarged A arrow view in FIG.

FIG. 6 is an exploded perspective view showing constituent members of the magnetic circuit unit in FIGS. 4 and 5;

[Explanation of symbols]

 3 Permanent magnet 5 Arm 6 Moving coil 10 Case 11 Holding member 14 Upper yoke 19 Lower yoke

Claims (1)

[Claims] 1. A permanent magnet is fixed to at least one of a recording medium rotatably provided through a drive motor and a pair of yokes provided to face each other in a case made of a non-magnetic material. And a magnetic circuit section, and a recording head that faces the recording medium at one end and a movable coil that faces the magnetic circuit section at the other end, respectively, and an arm swingably formed through a support shaft. A holding member and columns located near both sides of the holding member are erected on the inner surface of the case, and these members are integrally formed of a thermoplastic resin material and are magnetized in the thickness direction to form a flat plate. A permanent magnet assembly formed by a permanent magnet formed in a shape of a ring and a lower yoke made of a ferromagnetic material attracted to the back surface of the permanent magnet is held by the holding member when the case is molded. Fixed integrally with the,
An upper yoke formed of a ferromagnetic material so that the permanent magnet can be included in a contour projected on a plane is fixed to the pillar via a surface and a gap of the permanent magnet to form a magnetic circuit unit. Recording device.