JPH06284672A - Swing-type actuator - Google Patents

Abstract

PURPOSE:To surely perform a locking action at the time of being unoperated and at the same time reduce the number of a constituent parts and facilitate assembly by fixing an upper yoke to a support through the surface and the gap of a permanent magnet. CONSTITUTION:A support 2 and a holding member 11 for holding a permanent magnet assembly 13 in the surface of a basic plate 10 in one body respectively are projected to make a housing 20. A projection part 12 is provided in one body at one end part on the support 2 side of a permanent magnet 3, and a shield yoke 16 formed in the shape of a flat plate is provided close to the projection part 12. Next, a lower yoke is formed in the shape of a flat plate which has an outer contour corresponding to the outer contour of the permanent magnet 3 and is attracted in the rear surface of the permanent magnet 3 to constitute the shield yoke 16 and at the same time the permanent magnet assembly 13. An upper yoke 14 is formed in the shape of a quasi-triangular flat plate, and a mounting hole 15 is provided in the end part thereof. The upper yoke 14 is mounted on the support 2 of the basic plate 10 and fixed by a lock nut 2a.

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 a magnetic disk actuator, 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 that it can be made thin and cost-effective and the locking action is reliable when it is not operating.

[0002]

2. Description of the Related Art FIG. 4 is an explanatory view of a main part of 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. 4, reference numeral 1 denotes a yoke, which is formed in a flat plate shape with a ferromagnetic material such as soft iron, and is provided so as to face each other via a pillar 2 provided at an end portion. 3 is a permanent magnet, which is formed into 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 on the surface A magnetic gap 4 is formed.

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

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 switching of the swing direction is
This is performed by reversing the direction of the current supplied to the movable coil 6.

FIG. 5 is a perspective view of a main part showing the constituent members of the magnetic circuit in FIG. 4, and FIG. 6 is a perspective view showing the constituent members in FIG. 5 in an exploded manner. It shows with a code. In FIGS. 5 and 6, 8 is a stopper member, which is provided on the lower yoke 1,
When the arm 5 shown in FIG. 2 is stopped, a locking piece (not shown) made of a ferromagnetic material provided on the arm 5 and a locking permanent magnet (not shown) provided on the stopper member 8 are engaged. It is formed so as to match with each other, and prevents undesired swinging of the arm 5. Next, 9 is a positioning pin, which is provided on the lower yoke 1 and contacts the outer peripheral 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 shown in FIG. 5, after the respective constituent members are processed, the positioning pin 9 is first mounted at a predetermined position as shown in FIG. , The permanent magnet 3 is fixed to the yoke 1 with an adhesive. In this case, a process of heating and drying is required to cure the adhesive, and it takes time and man-hours to fix the permanent magnets 3, resulting in a problem of high cost. There is also a problem that harmful outgas is generated from the adhesive when the adhesive is heated and dried, 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 attached to 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 increase, which is a cause of high cost.

Further, it is necessary to lock the arm when the actuator is not in operation, and there have been conventionally provided mechanical lock mechanisms. However, it is often necessary to mount an extra member for mechanically locking them, and the life and reliability are often unsatisfactory. Therefore, a part of the drive permanent magnet is used,
Alternatively, a means has been proposed in which a locking permanent magnet is separately provided, and a magnetic attraction force is applied between the locking permanent magnet and a locking piece made of a ferromagnetic material provided in the movable coil to lock the moving coil (for example, Japanese Patent Publication No. 63-48110).

The magnetic attraction force, that is, the holding force, is
It is large when the moving coil is located in the latch zone (retraction zone) (for example, 15 gcm or more), and small in the data zone to facilitate the operation of the moving coil (for example, 1.5 gcm or less). ) Is required. However, the above-mentioned conventional device has a problem that such requirements cannot be satisfied.

The present invention solves the above-mentioned problems existing in the prior art, has a reliable locking action when not operating, has a small number of constituent members, and is easy to assemble,
Moreover, it is an object of the present invention to provide an oscillating actuator that can significantly reduce the manufacturing cost.

[0011]

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 magnet is attached to the surface of the permanent magnet. It consists of a housing with an air gap and an arm with one end fixed to the movable coil and the other end fixed to a functional member to allow it to swing. The movable coil is formed along the surface of the permanent magnet in the magnetic gap. In an oscillating actuator configured to be movable and to lock an arm when it is inoperative, a holding member and columns located near both sides of the holding member are erected on a substrate. , A housing is formed by integrally molding these members with a thermoplastic resin material, and is magnetized in the thickness direction to form a flat plate and a protruding portion is formed at the end portion on the side of the pillar. The holding member includes a permanent magnet assembly formed by a permanent magnet, a shield yoke made of a ferromagnetic material provided close to the protruding portion, and a lower yoke made of a ferromagnetic material attracted to the back surface of the permanent magnet. An upper part which is press-fitted and fixed to the movable coil and which is provided with a locking piece made of a ferromagnetic material at a portion corresponding to the projecting portion of the movable coil so that the permanent magnet can be included in the projected contour on the plane by the ferromagnetic material. The technical means of fixing the yoke to the pillar through a gap from the surface of the permanent magnet was adopted.

Next, in the second invention, a permanent magnet is fixed to at least one of a pair of yokes provided facing each other,
A housing having a magnetic air gap formed on the surface of the permanent magnet and an arm having a movable coil fixed to one end and a functional member fixedly attached to the other end to be swingable are provided. In a swing-type actuator configured to be movable along the surface of a permanent magnet and to lock an arm when it is inoperative, a holding member on a substrate and a support column located near both sides of the holding member. And a stand, and a housing is formed by integrally molding these members with a thermoplastic resin material, magnetized in the thickness direction, and formed into a flat plate shape and a projecting portion at the end portion on the side of the pillar. The formed permanent magnet, the shield yoke made of a ferromagnetic material provided close to the protrusion, and the lower yoke made of a ferromagnetic material attracted to the back surface of the permanent magnet. The permanent magnet assembly thus formed is integrally fixed so as to be held by the holding member when the housing is molded, and a locking piece made of a ferromagnetic material is provided at a portion of the movable coil corresponding to the projecting portion. The technical means is 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, 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, further thinning and higher performance are required. Therefore, in order to secure a high magnetic flux density in the magnetic gap, R-Fe-B system (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, known resins such as polyphenylene sulfide resin, polybutylene terephthalate resin, polyamide resin, polyimide resin, polyamideimide resin, polyester resin (preferably heat-resistant 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, 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 at the time of molding, the longitudinal elastic modulus in that direction becomes 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 liquid crystal has high fluidity and the molding becomes 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. Specific examples of such a liquid crystal polymer include Vectra A130 (1) which is a wholly aromatic thermotropic liquid crystalline polyester.
8 × 10 ⁴ ) (Unit: kg / cm ² , same hereafter), C130
(16 × 10 ⁴ ), A230 (30 × 10 ⁴ ), B23
0 (38 × 10 ⁴ ), A410 (21 × 10 ⁴ ), A4
22 (18 × 10 ⁴ ), C400 (17 × 10 ⁴ ), A
540 (16 × 10 ⁴ ) (above Celanese), XYD
AR RC-210 (16.2 × 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
× 10 ⁴ , polystyrene resin: 3.2 to 3.6 × 10 ⁴ , polyphenylene sulfide resin: 10 × 10 ⁴ (both units are kg / cm ² ), so a rigidity greater than that of general thermoplastic resin is used. Obtainable. Further, as the liquid crystal polymer, in order to improve mechanical strength, heat resistance and the like, a material 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 ×
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 and Sustain) and other polyphenylene sulphide
Do and the like.

[0020]

With the above construction, when the movable coil is inoperative, the magnetic attraction force acting between the protrusion provided on the end of the permanent magnet on the column side and the locking piece provided on the movable coil causes the movable coil to move. That is, the arm can be reliably locked. Further, when the movable coil is operated, since the locking piece is located away from the protruding portion, the magnetic attraction force does not act, and the swing of the movable coil, that is, the arm is not affected at all.

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. Become.

[0022]

FIG. 1 is an exploded perspective view showing 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. 4 to 6. In Figure 1,
Reference numeral 10 denotes a substrate, which is a holding member 1 which integrally holds a pillar 2 on the surface and a permanent magnet assembly 13 formed as described later.
1 and 1 are integrally projected to form a housing 20. In order to form such a housing 20, a mold for injection molding may be used, for example, a heated melt 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. .

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.

A projecting portion 12 is integrally provided at one end of the permanent magnet 3 on the side of the column 2, and a shield formed in a flat plate shape with a ferromagnetic material such as soft iron in close proximity to the projecting portion 12 is provided. A yoke 16 is provided. In this case, the shield yoke 16 can be attracted and held by the magnetic attraction force of the permanent magnet 3, but an adhesive may be used together. 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. A permanent magnet assembly 13 is configured with the shield yoke 16.

In the above case, the permanent magnet assembly 13
As a means for integrally holding the holding member 11,
There are press-fitting means and integral molding means. First, in the case of using the press-fitting means, the inner contour dimension of the holding member 11 is formed to be equal to or slightly smaller than the outer contour dimension of the permanent magnet assembly 13, and the permanent magnet assembly 13 is fixed. By press-fitting the inside, the holding member 11 can hold and fix. In this case, an adhesive may be used together.

On the other hand, in the case of the integral molding means, if the permanent magnet assembly 13 is previously inserted in a predetermined portion of the injection molding space and the above-mentioned molten material is injected,
At the same time when the substrate 10, the support 2 and the holding member 11 are formed, the holding member 11 holds and fixes the permanent magnet assembly 13 integrally.

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-described structure, the constituent members are integrally projected and the permanent magnet assembly 13 is integrally 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 setscrew 2a.

Next, FIG. 2 is a plan view showing the arm 5 in the embodiment of the present invention, and the same parts are designated by the same reference numerals as those in FIG. In FIG. 2, 7a is a hole through which the shaft 7 in FIG. 4 is inserted. Reference numeral 17 denotes a locking piece, which is provided at one side end portion of the movable coil 6 and has the protruding portion 1 shown in FIG.
It is provided in the part corresponding to 2. The locking piece 17 is preferably made of a ferromagnetic material such as soft iron, and is preferably provided integrally with the arm 5. In this case, the arm 5 is made of the above-mentioned glass fiber-containing polyphenylene sulfide resin, and can be molded integrally with the movable coil 6 and the locking piece 17 by the injection molding means.

A rocking type actuator can be constructed by assembling the magnetic circuit and the arm having the above construction as shown in FIG. The result of evaluating the locking characteristic of the arm 5 with respect to this swing type actuator will be described.

FIG. 3 is a diagram showing the relationship between arm angle and torque in the embodiment of the present invention. In FIG. 3, the position where the arm angle is 0 ° shows the case where the movable coil 6 of the arm 5 shown in FIG. 2 is located at the S pole side end of the permanent magnet 3 shown in FIG. At this position, the locking piece 17 shown in FIG. 2 faces the protrusion 12 shown in FIG. Therefore, the locking piece 17 is in the magnetic field of the protrusion 12 and is attracted to the protrusion 12, so that the arm 5 is locked.

Curves a and b in FIG. 3 respectively correspond to the one lacking the shield yoke 16 shown in FIG. 1 and the one attached. In this case, the torque means that when the arm 5 shown in FIG. 2 is at the position of the arm angle shown on the horizontal axis,
The torque required to swing the arm 5 in the horizontal direction is shown. First, as shown by the curve a, in the case where the shield yoke 16 shown in FIG. 1 is lacking, the torque at the arm angle of 0 ° is 25 g · cm or more, which is sufficient for the locking action of the arm 5. ， Arm angle 3.
Even in the data zone when rocking over 6 °,
The torque value is 3 g · cm. If the torque in the data zone is large as described above, the swing of the arm 5 is hindered. Therefore, in the data zone, it is required to be 1.5 g · cm or less as described above.

On the other hand, the curve b indicates that the shield yoke 16 is provided on the protrusion 12 as shown in FIG. 1, so that the strength of the magnetic field acting on the locking piece 17 shown in FIG. As a result of a slight decrease, as shown in FIG.
At the position of °, the torque has dropped to over 20 g · cm. However, this torque value is sufficiently higher than 15 g · cm required for locking the arm 5,
It is a value that can sufficiently satisfy the request. When the arm 5 oscillates and exceeds the arm angle of 3.6 °, which is the boundary between the latch zone and the data zone, the torque value drops drastically.
It is less than g · cm. Therefore, the arm 5 can be swung smoothly.

In the present invention, the shape and size of the shield yoke 16 shown in FIG. 1 are appropriately selected in accordance with the shape and size and the magnetic characteristics of the permanent magnet 3 and the protruding portion 12 which constitute the applicable swing type actuator. However, if the thickness is made too large, the torque value at the locking position, that is, the position where the arm angle is 0 ° is lowered, and a negative torque is generated in the data zone, which is not preferable.

In this embodiment, the example in which the peripheral edge of the holding member 11 which is integrally projected on the substrate 10 is formed continuously has been described, but it may 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 means for fixing the upper yoke 14 to the column 2, the set screw 2
Not only a, but also a rivet-like object may be driven in or press-fitted for fastening. Further, although the actuator for the magnetic head is described in the present embodiment, 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 the optical head and others.

[0036]

Since the present invention has the structure and operation as described above, the protrusion provided at the end of the permanent magnet on the column side and the movable coil are provided when the swinging actuator is inoperative. The movable coil, that is, the arm can be reliably locked by the magnetic attraction force acting between the locking piece. Further, when the movable coil is operated, since the locking piece is located away from the protruding portion, the magnetic attraction force does not act, and the swing of the movable coil, that is, the arm is not affected at all.

Further, by integrally molding most of the constituent members of the magnetic circuit, the number of constituent members can be greatly reduced, the assembling work can be facilitated, and the productivity can be greatly improved. It is possible to significantly reduce the manufacturing cost. Further, 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.

FIG. 2 is a plan view showing an arm according to an embodiment of the present invention.

FIG. 3 is a diagram showing a relationship between an arm angle and torque in the embodiment of the present invention.

4A and 4B are explanatory views of a main part showing an example of a conventional oscillating actuator, in which FIG. 4A is a partially crushed plane, and FIG. 4B is a view in the direction A in FIG.

5 is a perspective view of relevant parts showing constituent members of the magnetic circuit in FIG. 4. FIG.

FIG. 6 is an exploded perspective view showing constituent members in FIG.

[Explanation of symbols]

 2 Supports 3 Permanent magnets 10 Substrate 11 Holding member 12 Projection portion 16 Shield yoke 17 Locking piece

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. And an arm that is fixed and swingably formed. The movable coil is configured to be movable along the surface of the permanent magnet in the magnetic gap, and the arm is configured to be locked when it is inoperative. In an oscillating actuator, a holding member and struts located near both sides of the holding member are erected on a substrate, and a housing is formed by integrally molding these members with a thermoplastic resin material. , A permanent magnet magnetized in the thickness direction and having a flat plate shape and having a protrusion at the end on the side of the column, and a sheet made of a ferromagnetic material provided close to the protrusion. A permanent magnet assembly formed by a dough yoke and a lower yoke made of a ferromagnetic material adsorbed on the back surface of the permanent magnet is press-fitted and fixed to the holding member, and a ferromagnetic material is formed on a portion of the movable coil corresponding to the protruding portion. An upper yoke formed of a ferromagnetic material so that the permanent magnet can be included in a projected contour on a plane, and the upper yoke is fixed to the support via a surface and a gap of the permanent magnet. Characteristic swing actuator. 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. And an arm that is fixed and swingably formed. The movable coil is configured to be movable along the surface of the permanent magnet in the magnetic gap, and the arm is configured to be locked when it is inoperative. In an oscillating type actuator, a holding member and columns located near both sides of the holding member are erected on a substrate, and a housing is formed by integrally molding these members with a thermoplastic resin material. , A permanent magnet magnetized in the thickness direction and having a flat plate shape and having a protrusion at the end on the side of the column, and a sheet made of a ferromagnetic material provided close to the protrusion. And Doyoku, a permanent magnet assembly which is formed by a lower yoke made of a ferromagnetic material is adsorbed on a back surface of the permanent magnet,
When the housing is molded, it is integrally fixed so as to be held by the holding member, and a locking piece made of a ferromagnetic material is provided at a portion corresponding to the projecting portion of the movable coil. An oscillating actuator, wherein an upper yoke formed so that the permanent magnet can be contained therein is fixed to the support via a surface and a gap of the permanent magnet.