JPH0622530A - Rocking actuator - Google Patents

Abstract

PURPOSE:To reduce the number of parts of constituent members, and facilitate the assembling work, and cut down the manufacture cost by molding a board, where a holding frame for a permanent magnet, a holding member, and a pole are erected, respectively, integrally by thermoplastic resin material thereby forming a housing. CONSTITUTION:A pole 2, a holding frame 17 for holding a permanent magnet 16 for locking, and a holding member 11 for holding a permanent magnet 13 are erected each integrally so as to complete a housing 20, and using a mold for injection molding, heated and fused substance of resin is injected into the space for molding, and after cooling, it is taken out. What is more, by inserting the permanent magnet 16 for locking and the permanent magnet assembly 13 into the specified places in molds before molding, they are held and fixed, respectively, at the same time with the formation of the holding frame 17 and the holding member 11. Accordingly, in case of assembling a magnetic circuit, it will do to place an upper yoke 14 on the pole 2 of a board 10 and fix it with screws 2a, so the assembling work becomes easy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oscillating actuator such as an actuator for a magnetic disk, that is, an actuator configured such that a functional member such as a magnetic head oscillates so as to draw an arc locus. In particular, the present invention relates to an oscillating actuator improved so as to be thin and low cost.

[0002]

2. Description of the Related Art FIG. 2 is an explanatory view of a main part showing an example of a conventional rocking type actuator, in which (a) is a partially crushed plane,
(B) shows the arrow direction A in (a). In FIG. 2, reference numeral 1 denotes a yoke, which is formed of a ferromagnetic material such as soft iron into a flat plate shape, and is provided so as to face each other via a pillar 2 provided at an end portion. Reference numeral 3 denotes a permanent magnet, which is formed in a substantially trapezoidal flat plate shape, is magnetized in the thickness direction, and is fixed to the surface of the lower yoke 1 so that N and S magnetic poles appear on the surface, and the magnet is attached to the surface. A magnetic gap 4 is formed.

Reference numeral 5 denotes an arm, one end of which is fixed with a flat movable coil 6 and the other end of which is fixed with a functional member (not shown) such as a magnetic head. The movable coil 6 is formed by the permanent magnet 3. It is disposed so as to be rotatable or swingable via a shaft 7 so as to be positioned inside the magnetic gap 4.

When a signal current is applied to the movable coil 6 with the above-described structure, a driving force around the shaft 7 acts on the movable coil 6 according to Fleming's left-hand rule, causing the arm 5 to rotate or swing to move. For example, a magnetic head provided at the other end of 5 can be positioned on a predetermined recording track on the magnetic disk. The swing direction can be changed by
This is performed by reversing the direction of the current supplied to the movable coil 6.

FIG. 3 is a perspective view of the essential parts showing the constituent members of the magnetic circuit shown in FIG. 2, and FIG. 4 is an exploded perspective view showing the constituent members of FIG. 3, with the same parts referring to the same parts as in FIG. It shows with a code. In FIGS. 3 and 4, 8 is a stopper member, which is provided on the lower yoke 1,
When the arm 5 shown in FIG. 2 is stopped, the engaging piece (not shown) made of a ferromagnetic material provided on the arm 5 and the engaging permanent magnet (not shown) provided on the stopper member 8 are engaged. They are formed so as to fit together, and prevent undesired swinging of the arm 5. Next, 9 is a positioning pin, which is provided on the lower yoke 1 and is brought into contact with the outer peripheral portion of the permanent magnet 3 so that the permanent magnet 3 can be fixed at a predetermined position.

[0006]

In the case of assembling the magnetic circuit as shown in FIG. 3, after processing the respective constituent members, as shown in FIG. 4, first, the positioning pin 9 is mounted at a predetermined position. , The permanent 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 2 and the stopper member 8 are fixed, the upper yoke 1 is mounted on the support 2, and the set screw 2a is used to fix them. Since the fixing means of the members is screwing and / or caulking, the ratio of manual work is high.
Therefore, time and man-hours are increased, which causes a high cost.

On the other hand, in recent years, demands for thinning and cost reduction of this type of oscillating actuator have become increasingly strict, and in the above-mentioned conventional structure, the number of constituent members is large and the assembling cost is high. Since it is bulky, the above requirements cannot be satisfied.

The present invention solves the above-mentioned problems existing in the prior art, and provides an oscillating actuator which has a small number of constituent members, is easy to assemble, and can significantly reduce the manufacturing cost. The purpose is to do.

[0010]

In order to achieve the above object, in the first invention, a permanent magnet is fixed to at least one of a pair of yokes provided facing each other, and a magnetic field is applied to the surface of the permanent magnet. The housing is formed with an air gap, and the arm is formed with a movable coil at one end and a functional member fixed at the other end, and the arm is swingably formed. The movable coil is formed along the surface of the permanent magnet in the magnetic air gap. A swing-type actuator configured to be movable and configured to lock the arm by engaging a locking piece provided on the movable coil side of the arm and a permanent magnet for locking provided on the housing when the arm is inoperative. In the above method, the holding frame, the holding member, and the columns located near both sides of the holding member are erected on the substrate, and these members are integrally molded by a thermoplastic resin material. The permanent magnet assembly is formed by a permanent magnet that forms a housing and is magnetized 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 permanent magnet may be integrally fixed so as to be held by the holding member when the housing is molded, and the locking permanent magnet may be press-fitted and fixed to the holding frame, and the permanent magnet may be included in the contour projected onto the plane by the ferromagnetic material. The technical means of fixing the thus formed upper yoke to the pillar via the surface of the permanent magnet with a gap.

Next, in the second invention, a permanent magnet is fixed to at least one of a pair of yokes provided so as to face each other,
A housing having a magnetic gap formed on the surface of the permanent magnet and an arm having a movable coil fixed to one end and a functional member fixed to the other end to be swingable are provided. The arm is configured to be movable along the surface of the permanent magnet, and the arm is locked by the engagement of the locking piece provided on the movable coil side of the arm and the locking permanent magnet provided on the housing when not operating. In the swing-type actuator configured as described above, the holding frame, the holding member, and the columns located near both sides of the holding member are erected on the substrate, and these members are integrally formed of a thermoplastic resin material. To form a housing,
A permanent magnet magnetized in the thickness direction and formed in a flat plate shape,
A permanent magnet assembly formed by a lower yoke made of a ferromagnetic material attracted to the back surface of the permanent magnet and a locking permanent magnet are held by the holding member and the holding frame when the housing is molded. Fixed together,
A technical means has been adopted in which an upper yoke formed of a ferromagnetic material so that the permanent magnet can be included in a projected contour on a plane is fixed to the pillar through a gap from the surface of the permanent magnet.

In the present invention, since the permanent magnet as a constituent member has a limited thickness, its operating point cannot be set high, so that a rare earth magnet having a large coercive force is preferably used. 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 is preferable). 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 with 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 the liquid crystal polymer is molded at a liquid crystal state temperature lower than the complete melting temperature, the fluidity is high and the molding is easy. 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.

[0019]

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. .

[0020]

FIG. 1 is an exploded perspective view showing the components of a magnetic circuit according to an embodiment of the present invention, and the same parts are designated by the same reference numerals as those in FIGS. In FIG.
Reference numeral 10 is a base plate, on the surface of which a pillar 2 and a permanent magnet 16 for locking are attached.
And a holding member 17 for integrally holding a permanent magnet assembly 13 formed as will be described later.
Are integrally projected to form a housing 20. An injection mold is used to integrally project the above-mentioned constituent members and to hold the locking permanent magnet 16 and the permanent magnet assembly 13 integrally by the holding frame 17 and the holding member 11, respectively. For example, a heated and melted product of polyphenylene sulfide resin containing glass fibers may be injected into the molding space, and after cooling and solidification, it may be taken out from the molding space. Note that the permanent magnet for locking 1
If the 6 and the permanent magnet assembly 13 are inserted into a predetermined position in the injection molding die before molding, the holding frame 17 and the holding member 11 are formed at the same time when the heating melt is injected. The holding permanent magnet 16 and the permanent magnet assembly 13 are held and fixed by the holding frame 17 and the holding member 11, respectively.

Since the locking permanent magnet 16 is generally small in size, it is often difficult to insert the locking permanent magnet 16 into the injection molding die. In such a case, only the holding frame 17 may be integrally molded together with other components, and the locking permanent magnet 16 may be press-fitted and fixed in the holding frame 17 after the molding. An adhesive may be used together when press-fitting.
In this case, the magnetic pole direction of the locking permanent magnet 16 is the vertical direction,
It may be horizontal.

Next, the permanent magnet 3 constituting the permanent magnet assembly 13 is formed of, for example, an Nd-Fe-B based magnet material into a substantially fan-shaped flat plate, magnetized in the thickness direction, and has N, S 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, a lower yoke (not shown) 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 is attracted to the back surface of the permanent magnet 3 to be permanently attached. The magnet assembly 13 is configured.

Reference numeral 14 denotes an upper yoke, which is formed of a ferromagnetic material similar to that of the lower yoke into a pseudo-triangular flat plate shape, and a mounting hole 15 is provided at an end thereof. 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 structure, the constituent members are integrally projected and the permanent magnet assembly 13 is integrally held and held in the holding member 11 on the support column 2 of the substrate 10. The upper 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 projecting integrally on the substrate 10 was formed continuously, but it may also be formed discontinuously or in the form of a plurality of protrusions. Are the same, in short, the permanent magnet assembly 1
It suffices to have a function capable of holding and fixing 3. Further, as a means for fixing the upper yoke 14 to the column 2, a set screw 2
Not only a, but also a rivet-like object may be driven in or press-fitted for fastening. Further, in the present embodiment, the actuator for the magnetic head is described, but the functional member to be provided at one end of the arm is
The operation is the same not only for the magnetic head but also for an optical head and others.

[0026]

Since the present invention has the structure and operation as described above, the number of the constituent members can be greatly reduced by integrally molding most of the constituent members of the magnetic circuit. As a result, the productivity can be significantly improved, and as a result, the manufacturing cost can be significantly reduced. Furthermore, by integrating most of the constituent members, there is an effect that the oscillation type actuator as a whole can be made smaller and thinner.

[Brief description of drawings]

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

2A and 2B are explanatory views of a main part showing an example of a conventional swing-type actuator, in which FIG. 2A is a partially crushed plane, and FIG. 2B is a view in the direction A in FIG.

FIG. 3 is a perspective view of relevant parts showing constituent members of the magnetic circuit in FIG.

FIG. 4 is a perspective view showing the constituent members in FIG. 3 in an exploded manner.

[Explanation of symbols]

 2 Supports 3 Permanent magnets 10 Substrate 11 Holding member 14 Upper yoke 16 Permanent magnets 17 for locking Holding frame

Claims (2)

[Claims] 1. A housing in which a permanent magnet is fixed to at least one of a pair of yokes facing each other, and a magnetic gap is formed on the surface of the permanent magnet, and a movable coil is provided at one end and a functional member is provided at the other end. Each of which is fixed and swingably formed, and the movable coil is configured to be movable along the surface of the permanent magnet in the magnetic gap, and is provided on the movable coil side of the arm when not operating. An oscillating actuator configured to lock an arm by engaging a locking piece with a locking permanent magnet provided in a housing, a holding frame, a holding member, and both side parts of the holding member on a substrate. Protrusions located near each other are respectively provided upright, and these members are integrally molded with a thermoplastic resin material to form a housing, which is magnetized in the thickness direction and formed into a flat plate shape. A permanent magnet assembly formed by a magnet and a lower yoke made of a ferromagnetic material attracted to the back surface of the permanent magnet is integrally fixed so as to be held by the holding member when the housing is molded, and is also held. An upper yoke formed by press-fitting and fixing a locking permanent magnet to a frame so that the permanent magnet can be included in a projected contour on a plane by a ferromagnetic material is attached to the pillar through a gap with the surface of the permanent magnet. An oscillating actuator characterized by being fixed. 2. A housing in which a permanent magnet is fixed to at least one of a pair of yokes provided facing each other, and a magnetic gap is formed on the surface of the permanent magnet, and a movable coil is provided at one end and a functional member is provided at the other end. Each of which is fixed and swingably formed, and the movable coil is configured to be movable along the surface of the permanent magnet in the magnetic gap, and is provided on the movable coil side of the arm when not operating. An oscillating actuator configured to lock an arm by engaging a locking piece with a locking permanent magnet provided in a housing, a holding frame, a holding member, and both side parts of the holding member on a substrate. Properly arranging the pillars located in the vicinity, and forming a housing by integrally molding these members with a thermoplastic resin material, magnetized in the thickness direction and formed into a flat plate shape. A permanent magnet assembly formed by a magnet and a lower yoke made of a ferromagnetic material attracted to the back surface of the permanent magnet, and a locking permanent magnet are held by the holding member and the holding frame when the housing is molded. The upper yoke formed so that the permanent magnet can be included in the projected contour on the plane by the ferromagnetic material is fixed to the column via the surface and the gap of the permanent magnet. Characteristic swing actuator.