JP3298227B2 - Swing type actuator - Google Patents

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 so that a functional member such as a magnetic head oscillates in an arc trajectory. In particular, the present invention relates to an oscillating actuator which is improved so as to be thinner and lower in cost.

[0002]

2. Description of the Related Art FIGS. 15 (a) and 15 (b) are explanatory views of a main part of an example of a conventional oscillating type actuator. FIG. 15 (a) is a partially broken plane, and FIG. FIG.
Reference numeral 1 denotes a yoke, which is formed in a flat plate shape from a ferromagnetic material such as soft iron, for example, and provided to face each other via a support column 2 provided at an end. 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. The magnetic gap 4 is formed.

An arm 5 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. The movable coil 6 is formed by the permanent magnet 3. And is rotatably or oscillated via a shaft 7 so as to be positioned within the magnetic gap 4.

When a signal current is applied to the movable coil 6 according to the above configuration, a driving force about the shaft 7 acts on the movable coil 6 according to Fleming's left-hand rule to rotate or swing the arm 5, For example, a magnetic head provided at the other end of the magnetic disk 5 can be positioned at 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. 16 is a perspective view showing the main parts of the magnetic circuit shown in FIG. 15, and FIG. 17 is an exploded perspective view showing the constituent parts in FIG.
5 are denoted by the same reference numerals. In FIGS. 16 and 17, reference numeral 8 denotes a stopper member, which is provided on the lower yoke 1 and is formed so as to engage with the arm 5 when the arm 5 shown in FIG. Prevent desired oscillations. Next, reference numeral 9 denotes 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 order to assemble the magnetic circuit as shown in FIG. 16, after the respective constituent members are processed, as shown in FIG. 17, the positioning pins 9 are first mounted at predetermined positions. , The permanent magnet 3 is fixed to the yoke 1 with an adhesive.
Stick to In this case, a process of heating and drying to cure the adhesive is required, and the work of fixing the permanent magnet 3 requires time and man-hours, resulting in an increase in cost. Further, when the adhesive is dried by heating, there is a problem that harmful outgas is generated from the adhesive and the environment may be polluted.

Next, after the permanent magnet 3 is fixed to the yoke 1, the column 2 and the stopper member 8 are fixed, the upper yoke 1 is mounted on the column 2, and fixed with the set screw 2a. In this case, the arm 7 on the outer periphery of the support 2 (FIG. 15)
An O-ring (not shown) is fitted as a cushioning material at a position opposed to the O-ring. However, since the fixing means of these components includes screwing and / or caulking, the ratio of manual work is high. Therefore, time and man-hours are increased, which causes an increase in cost.

Further, in order to increase the thrust on the movable coil 6, an example of using a permanent magnet 3 having a large magnetic energy product, for example, a rare-earth permanent magnet, has been increasing. However, there is a problem that the lower yoke 1 constituting the magnetic path may be magnetically saturated, and the high performance and high air gap magnetic flux density of the permanent magnet 3 cannot be exhibited. Increasing the thickness of the yoke 1 is not preferable because it increases the thickness of the actuator.

Further, when the permanent magnet 3 is formed of a sintered magnet material, it is inherently brittle, so that minute chips are easily generated and, for example, materials such as Nd-Fe-B magnets are used. When formed, the surface is easily oxidized during use. For this reason, it is necessary to perform a surface treatment such as plating on the surface of the permanent magnet 3, and there is a problem that the manufacturing cost increases.

On the other hand, in recent years, demands for thinning and cost reduction of this type of oscillating type actuator have become increasingly severe, and the above-mentioned conventional configuration has a large number of components and a high assembly cost. Because of the bulk, the above requirements cannot be satisfied.

[0011] The present invention solves the above-mentioned problems in the prior art, and provides an oscillating actuator which has a small number of constituent members, is easy to assemble, and can greatly reduce the manufacturing cost. It is intended to do so.

[0012]

According to a first aspect of the present invention, a permanent magnet is fixed to at least one of a pair of opposed yokes, and a surface of the permanent magnet is fixed to the permanent magnet. A housing formed with an air gap, and an arm formed with a movable coil at one end and a functional member fixed at the other end to be swingable, and the movable coil is formed along the surface of the permanent magnet in the magnetic air gap. In the oscillating actuator configured to be movable, a holding member and a column located near both sides of the holding member are erected on a substrate, and at least the substrate, the holding member and the column are integrally formed of a thermoplastic resin material. A permanent magnet formed in a flat shape by magnetizing the housing in the thickness direction, and a lower yoke made of a ferromagnetic material adsorbed on the back surface of the permanent magnet. Is integrally fixed so as to be held by the holding member at the time of molding the housing, and the ferromagnetic material is formed so that the permanent magnet can be included in a projected contour on a plane. Technical means was adopted in which the upper yoke was fixed to the column by a gap with the surface of the permanent magnet.

Next, in the second invention, a permanent magnet is fixed to at least one of a pair of yokes provided to face each other,
The permanent magnet comprises a housing having a magnetic gap formed on the surface thereof, and a movable coil at one end and an arm formed with a functional member fixed to the other end so as to be swingable. The movable coil is formed within the magnetic gap. In an oscillating actuator configured to be movable along the surface of a permanent magnet, a holding member and a column located near both sides of the holding member are erected on a substrate, and at least the substrate, the holding member and the column are formed. A housing is formed by integral molding with a thermoplastic resin material, and a magnet formed in a thickness direction is magnetized in a plate shape to form a permanent magnet, and a lower yoke made of a ferromagnetic material adsorbed on the back surface of the permanent magnet. The permanent magnet assembly formed as described above is integrally fixed so as to be held by the holding member when the housing is formed, and the permanent magnet assembly formed on the back surface of the lower yoke. An upper yoke formed by filling a closing member made of a thermoplastic resin into the mark of the determining pin by molding means, and forming an upper yoke formed of a ferromagnetic material so that the permanent magnet can be included in a projected contour onto a plane, is provided with a gap with the surface of the permanent magnet A technical means of fixing to the above-mentioned column through the support is adopted.

Further, in the third invention, a permanent magnet is fixed to at least one of a pair of yokes provided to face each other,
The permanent magnet comprises a housing having a magnetic gap formed on the surface thereof, and a movable coil at one end and an arm formed with a functional member fixed to the other end so as to be swingable. The movable coil is formed within the magnetic gap. In an oscillating actuator configured to be movable along the surface of a permanent magnet, a holding member and a column located near both sides of the holding member are erected on a substrate, and at least the substrate, the holding member and the column are formed. A housing is formed by integral molding with a thermoplastic resin material, and a magnet formed in a thickness direction is magnetized in a plate shape to form a permanent magnet, and a lower yoke made of a ferromagnetic material adsorbed on the back surface of the permanent magnet. Are fixed together so as to be held by the holding member at the time of molding the housing, and a ferromagnetic material is used to project a projection wheel onto a plane. By inserting an upper yoke formed so that the permanent magnet can be included in the column through a gap with the surface of the permanent magnet, and forming a locking portion by thermal melting at the end of the column. The technical means of sticking to the column was adopted.

In a fourth aspect, a permanent magnet is fixed to at least one of a pair of yokes provided to face each other.
The permanent magnet comprises a housing having a magnetic gap formed on the surface thereof, and a movable coil at one end and an arm formed with a functional member fixed to the other end so as to be swingable. The movable coil is formed within the magnetic gap. In an oscillating actuator configured to be movable along the surface of a permanent magnet, a holding member and a column located near both sides of the holding member are erected on a substrate, and a diameter of the column is reduced at an end of the column. A permanent magnet formed in a flat shape by forming a housing by providing a locking portion formed so as to be able to integrally mold at least the substrate, the holding member and the support column with a thermoplastic resin material, and magnetizing in the thickness direction. A permanent magnet assembly formed by a lower yoke made of a ferromagnetic material adsorbed on the back surface of the permanent magnet is held by the holding member when the housing is formed. And a locking hole formed by ferromagnetic material so that the permanent magnet can be included in the projected contour on a plane, and having an inner diameter smaller than the outer diameter of the locking portion. A technical means is adopted in which the upper yoke is fixed to the support column through a gap with the surface of the permanent magnet by fitting a locking hole to the locking portion.

Next, in a fifth aspect, a permanent magnet is fixed to at least one of a pair of yokes provided to face each other,
The permanent magnet comprises a housing having a magnetic gap formed on the surface thereof, and a movable coil at one end and an arm formed with a functional member fixed to the other end so as to be swingable. The movable coil is formed within the magnetic gap. In an oscillating actuator configured to be movable along the surface of a permanent magnet, a holding member and a column located near both sides of the holding member are erected on a substrate, and at least the substrate, the holding member and the column are formed. A housing is formed by integral molding with a thermoplastic resin material, and is magnetized in the thickness direction to form a flat permanent magnet, and a flat magnet made of a ferromagnetic material adsorbed on the back surface of the permanent magnet. A permanent magnet assembly formed by a lower yoke and an auxiliary yoke made of a ferromagnetic material and protruding from a longitudinal end of the lower yoke is used for molding the housing. An upper yoke held by the holding member and integrally fixed so as to include the auxiliary yoke in the support column, and formed by a ferromagnetic material so that the permanent magnet can be included in a projected contour onto a plane, is provided with a permanent yoke. A technical means of fixing the magnet to the column through the gap and the surface of the magnet was employed.

In the sixth invention, a permanent magnet is fixed to at least one of a pair of yokes provided to face each other,
The permanent magnet comprises a housing having a magnetic gap formed on the surface thereof, and a movable coil at one end and an arm formed with a functional member fixed to the other end so as to be swingable. The movable coil is formed within the magnetic gap. In an oscillating actuator configured to be movable along the surface of a permanent magnet, a holding member and a column located near both sides of the holding member are erected on a substrate, and at least the substrate, the holding member and the column are formed. A housing is formed by integral molding with a thermoplastic resin material, and a magnet formed in a thickness direction is magnetized in a plate shape to form a permanent magnet, and a lower yoke made of a ferromagnetic material adsorbed on the back surface of the permanent magnet. The permanent magnet assembly formed by the above is held by the holding member at the time of molding the housing, and integrally fixed so as to cover the surface of the permanent magnet, The formed upper yoke so that the permanent magnets within the projection contour of the plane by a magnetic material may be included, via the surface and gaps of the permanent magnet is fixed to the support column, employing the technical means of.

In the first to sixth aspects of the present invention, a buffer member made of an elastic resin material can be fixed to the outer periphery of the column at least at a portion facing the arm by molding means. In the second aspect, the fixing of the cushioning member may be performed simultaneously with the molding of the closing member.

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

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, polyamide imide resin and polyester resin (preferably resins having heat resistance) are used. ) Can be used.

Among the above resins, the longitudinal elastic modulus (measuring method:
(ASTM D-638) is preferably 10 × 10 ⁴ kg / cm ² or more (preferably 13 × 10 ⁴ kg / cm ² or more). 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 (having 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, an aromatic dicarboxylic acid, and an aromatic diol; c)
There are those having various basic compositions, such as a copolymer of poly-p-hydroxybenzoate and naphthoic acid, and those of wholly aromatic (b) and (c) are preferred in terms of strength and elastic modulus, (C) is more preferred. In particular, the wholly aromatic polyester resin (c) has rigid molecular chains oriented in the flow direction at the time of molding, so that not only the longitudinal elastic modulus in that direction is large, but also the vibration absorption characteristics are good and the linear expansion coefficient is high. There is an advantage that it is small (close to a metal material).

When the liquid crystal polymer is molded at a liquid crystal state temperature lower than the complete melting temperature, the flowability is high and the molding is easy. Particularly, the longitudinal elastic modulus (tensile elastic modulus) is 16 × 10 ⁴ kg /
It is preferable 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 is kg / cm ² , the same applies hereinafter), 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 ) (Dartco).

Incidentally, the modulus of longitudinal elasticity 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 (all units are kg / cm ² ), so that the rigidity is greater than that of using a general thermoplastic resin. Obtainable. Further, as the liquid crystal polymer, a material to which a filler such as glass fiber or carbon fiber is added in order to improve mechanical strength and heat resistance can be used. The addition amount is 10
It is desirably 50% by weight, more preferably 20 to 40% by weight.

In the present invention, the above-mentioned thermoplastic resin
Flexural modulus as fat (Measurement method: ASTM D-792)
Is 13 × 10^Fourkg / cm^TwoThese can also be used effectively
You. As such a resin, for example, the aforementioned Vectra A
130 (15 × 10^Four) (Unit is kg / cm^TwoEtc.
), C130 (14 × 10^Four), A230 (29 × 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), Ryton R
-4 (14 × 10^Four) (Philips Oil), DIC P
PS FZ ・ 1140 (14 × 10^Four) 、 ASAHI ・
PPS RG-40JA (14.4 × 10^Four) (Asahi Glass),
Fortron 1140A1 (13 × 10^Four) (Polyplastic
Styx), GS-40 (15 × 10^Four), G-10
(20 × 10^Four), G-6 (18 × 10^Four), G-4F
(14 × 10 ^Four), FC-5 (16 × 10^Four) (East
Polyphenylene sulphie such as So Sussteel)
And the like.

In the third aspect of the present invention, as the means for forming the engaging portion at the end of the support by heat melting, for example, high-frequency heating, vibration heating by ultrasonic waves, or other known heating means can be used. In short, it is only necessary to locally heat the end of the column above the softening point of the thermoplastic resin, and it is also possible to use pressing means for forming the locking portion in combination with the heating means.

Next, in the fifth invention, since the auxiliary yoke is included in the support, it is preferable to form the cross section into a hollow cylindrical shape or an arc shape. Further, the auxiliary yoke and the lower yoke may be separately manufactured and integrated by known fastening means or fixing means. However, it is effective to integrally form them by, for example, pressing means.

[0028]

According to the above construction, the number of constituent members can be reduced, and since most of the constituent members are integrally formed, the assembling work is facilitated and the production cost can be greatly reduced. .

According to the fifth aspect of the present invention, since the auxiliary yoke is protruded from the lower yoke, magnetic saturation of the yoke member can be prevented, and the air gap magnetic flux density can be maintained at a high level. In the sixth invention, a coating is simultaneously formed on the surface of the permanent magnet at the time of the molding, so that a rustproof function is provided.

[0030]

FIG. 1 is an exploded perspective view showing components of a magnetic circuit according to a first embodiment of the present invention, and the same parts are denoted by the same reference numerals as those in FIGS. In FIG. 1, reference numeral 10 denotes a substrate, on the surface of which is a column 2, a stopper member 8, and a permanent magnet assembly 13 formed as described later.
Are integrally formed to form a housing 20. Projecting the above components integrally,
And, in order to integrally hold the permanent magnet assembly 13 by the holding member 11, an injection mold described later is used, and a heated melt of, for example, a polyphenylene sulfide resin containing glass fiber is injected into the molding space, After cooling and solidifying, it may be taken out of the molding space. If the permanent magnet assembly 13 is inserted at a predetermined position in the injection molding die before molding, the holding member 11 is formed by injection of the heated melt, and at the same time, the holding member 11 The magnet assembly 13 is held and fixed.

Next, the permanent magnet 3 constituting the permanent magnet assembly 13 is formed in a substantially fan-shaped or pseudo-triangular flat plate shape using, for example, Nd—Fe—B-based magnet material, magnetized in the thickness direction, and formed on the surface. The configuration is such that N and S magnetic poles appear. When manufacturing such a permanent magnet 3, two permanent magnets may be joined together at 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 form a permanent magnet. The magnet assembly 13 is constituted.

Reference numeral 14 denotes an upper yoke, which is formed in a pseudo-triangular plate shape using the same ferromagnetic material as the lower yoke, and has a mounting hole 15 at an end. The upper yoke 14
Are formed such that the permanent magnet 3 can be included in a contour projected on a plane. 2a is a set screw.

With the above configuration, when assembling the magnetic circuit, the constituent members are integrally protruded, and the permanent magnet assembly 13 is integrally held and fixed in the holding member 11 on the support column 2 of the substrate 10. The upper yoke 14 may be placed and fixed with the set screw 2a.

FIG. 2 is a longitudinal sectional view of an essential part showing an example of an injection mold for molding the housing 20 shown in FIG. FIG.
In the figure, reference numerals 21 and 22 denote a fixed type and a movable type, respectively, and a guide hole 23 provided in the fixed type 21 is configured to be engaged with a guide pin 24 provided in a movable type 22 formed to be vertically movable. The fixed mold 21 is configured by integrally fastening a lower mold 25, a support 26, and a template 27, and the movable mold 22 is configured by integrally fastening an upper mold 28 and a template 29.

Next, the lower mold 25 is provided with a housing 20 having the support 2, the substrate 10, the holding member 11 and the like shown in FIG.
A cavity 30 for molding corresponding to the contour of is provided, and a positioning pin 31 and a core pin 32 are provided so as to face the cavity 30. Reference numeral 33 denotes an extruding plate, which is provided with an extruding pin 34 having a tip portion which coincides with the contour of the cavity 30, and is provided with an extruding rod 35 and a returning rod 36. Reference numeral 37 denotes a positioning pin provided on the upper die 28, which is provided so as to come into contact with the lower yoke 38 fixed to the permanent magnet 3 inserted into the cavity 30 for molding. A sprue 39 is provided over the upper mold 28 and the mold plate 29 and is formed so as to communicate with the cavity 30 via the gate 40.

An embodiment in which the housing 20 which is a component of the swing type actuator of the present invention is formed by using the injection mold having the above-described structure will be described. First, the permanent magnet 3
The lower yoke 38 is inserted into the cavity 30 in a state where the lower yoke 38 is adsorbed to the rear surface of the cavity. In this case, the positioning in the horizontal direction is performed by the positioning pin 31, and the permanent magnet assembly including the permanent magnet 3 and the lower yoke 38 is set at a predetermined position in the cavity 30.

Next, when the movable mold 22 is set on the fixed mold 21 via the guide pins 24 and the guide holes 23, the front ends of the positioning pins 37 abut on the back surface (the upper surface in FIG. 2) of the lower yoke 38. The permanent magnet 3 and the lower yoke 38 are prevented from floating due to molding pressure during injection molding. In this state, if a hot melt of polyphenylene sulfide resin containing glass fiber is injected and filled into the cavity 30 via the sprue 39 and the gate 40, the housing as shown in FIG. 1 is formed.

After the filled resin material is solidified, the movable mold 22 is moved upward, and the extruded plate 33 is moved upward through the rod 35 for extrusion. Can be extruded. After the interior of the cavity 30 is cleaned, the permanent magnet 3 and the lower yoke 38 which are to be formed into the next molded body are inserted into the cavity 30, and the next molding operation is performed. When the movable mold 22 is set to the fixed mold 21, the return rod 36
Is pushed into contact with the surface of the upper mold 28, and the extrusion plate 33 is pushed back downward, so that the extrusion pin 34 returns to the state before molding.

FIG. 3 is an exploded perspective view showing components of a magnetic circuit according to a second embodiment of the present invention, and the same parts are denoted by the same reference numerals as in FIG. In FIG. 3, reference numeral 16 denotes a shock-absorbing member, which is integrally fixed to the outer periphery of the column 2 by filling an elastic resin material such as urethane rubber in another molding die after the housing 20 is molded.

With such a configuration, when the arm 5 as shown in FIG. 15 is interposed, undesired deformation occurs in the movable coil 6 even when the movable coil 6 comes into contact with the column 2. Can be prevented.

FIG. 4 is a plan view of an essential part showing an example of a housing 20 according to a second embodiment of the present invention, and FIG.
FIG. 4 is a sectional view taken along the line B, and the same parts are denoted by the same reference numerals as those in FIGS. 2 and 3. 4 and 5, 31
a and 37a are positioning pins 31, 3 shown in FIG.
7 are formed on a part of the substrate 10 and the holding member 11. If such pin traces 31a and 37a are present, there is a possibility that burrs may fall off and foreign matter may be deposited, and the lower yoke 38 is usually formed of a steel material (for example, soft iron or steel). For example, when used without a surface treatment such as plating, if exposed to the atmosphere, the lower yoke 38 will rust, so in the present invention, the pin marks 31a,
37a is filled with closing members 41 and 42.

That is, the housing 20 is housed in a mold provided with a cavity corresponding to the contours of the support 2, the substrate 10 and the holding member 11, and the thermoplastic resin is pin-marked 31a, 3b.
The sealing members 41 and 42 are formed by filling the inside of the inside 7a. Next, the outer periphery of the column 2 is filled with an elastic resin material such as urethane rubber using another molding die to form a ring-shaped buffer member 16. The molding of the cushioning member 16
It may be performed simultaneously with the molding of the closing members 41 and 42.
In this way, the molding die can be shared, and
This is effective for shortening the molding process.

FIG. 6 is a perspective view showing a magnetic circuit according to a third embodiment of the present invention.
Are indicated by the same reference numerals. In FIG. 6, when assembling the magnetic circuit, the upper yoke 14 is mounted on the support 2 of the substrate 10 in which the constituent members are integrally protruded and the permanent magnet assembly 13 is integrally held and fixed in the holding member 11. Is placed, and by locally heating the end of the column 2 (above the softening point of the resin) to form the locking portion 17 by thermal melting, the column 2 and the upper yoke 14 can be fixed.

FIGS. 7A and 7B are enlarged cross-sectional views of a main part showing the vicinity of the end of the column 2 in FIG. 6, wherein FIG. 7A shows a state before fixing, and FIG. 7B shows a state after fixing. That is, after the upper yoke 14 is placed on the end 2b of the support column 2 via the mounting hole 15, the end 2b is locally heated by, for example, an ultrasonic vibrator or the like, and is connected as shown in FIG. A stop 17 is formed. The locking portion 17 has a larger diameter than the mounting hole 15,
Further, since the upper yoke 14 is sandwiched between the column 2 and the support 2, the fixed state is completed.

FIG. 8 is a perspective view showing a magnetic circuit according to a fourth embodiment of the present invention, and FIG. 9 is an enlarged perspective view showing the vicinity of the end of the column 2 in FIG. Are indicated by the same reference numerals. 8 and 9,
Reference numeral 18 denotes a locking portion which is formed in a hollow cylindrical shape and has a tapered portion 19 at an end. Next, reference numeral 18a denotes a split groove, which is radially provided on the locking portion 18 and the tapered portion 19, and the locking portion 18 and the tapered portion 19 are formed so as to be able to reduce the diameter.

With the above configuration, when assembling a magnetic circuit, the constituent members are integrally protruded, and the permanent magnet assembly 13 is integrally held and fixed in the holding member 11 on the support column 2 of the substrate 10. Then, the upper yoke 14 is placed, and the mounting hole 15 may be fitted to the locking portion 18 at the end of the column 2. That is, since the inner diameter of the mounting hole 15 is formed smaller than the outer diameter of the engaging portion 18, the engaging portion 18 is reduced in diameter by the above-mentioned fitting, and the upper yoke 14 is supported by the repulsive force of the supporting column 2. It can be fixed to Since the tapered portion 19 is provided at the end of the locking portion 18 as shown in FIG.
The work of fitting the upper yoke 14 is easy.

FIG. 10 is a partial cross-sectional plan view showing a housing 20 in a fifth embodiment of the present invention, and FIG. 11 is a cross-sectional view taken along the line CC in FIG. 10, where the same reference numerals are used as in FIG. Indicated by In FIG. 10 and FIG.
Is a lower yoke, which is formed of a ferromagnetic material such as soft iron in a flat plate shape as described above, has a portion corresponding to the outer contour of the permanent magnet 3, and has a longitudinal end portion of the support column 2. It is formed to reach the part.

Reference numeral 47 denotes an auxiliary yoke, which is formed of the same material as that of the lower yoke 46, for example, has a C-shaped or arcuate cross section, and is fixed to the longitudinal end of the lower yoke 46. Known fastening means, welding means, and the like can be used as the means for fixing the auxiliary yoke 47 and the lower yoke 46.
Both may be integrally formed by press molding means or the like.

The permanent magnet 3 is attracted to the lower yoke 46 having the above-described structure to form the permanent magnet assembly 13, and if the injection molding is performed using the injection molding die as described above, the permanent magnet 3
Are held and fixed by the holding member 11, and the lower yoke 46 and the auxiliary yoke 47 are included in the substrate 10 and the support column 2, respectively, and are integrated therewith. According to the above configuration, the magnetic saturation conventionally experienced in the lower yoke 46 can be eliminated, and the air gap magnetic flux density on the surface of the permanent magnet 3 can be maintained at a high level. The auxiliary yoke 4
7 may be provided at the position 47a shown in FIGS.

When assembling the magnetic circuit according to the above configuration, the constituent members are integrally protruded, and the permanent magnet assembly 13 is integrally held and fixed in the holding member 11 on the column 2 of the substrate 10. As shown in FIG. 1, the upper yoke 14 may be placed and fixed by the set screw 2a.

FIG. 12 is an exploded perspective view showing components of a magnetic circuit according to a sixth embodiment of the present invention, and the same parts are denoted by the same reference numerals as in FIG. In FIG.
Reference numeral 48 denotes a cover, which is formed integrally with the holding member 11 and is provided so as to cover the surface of the permanent magnet 3. In this case, if the thickness of the coating 48 is large, the decrease in the magnetic flux density in the magnetic air gap is large, while if the thickness is too small, the rust prevention effect on the permanent magnet 3 is reduced.
The range is preferably 3 mm, more preferably 0.05 to 0.1 mm.

FIG. 13 is a longitudinal sectional view of an essential part showing an example of an injection mold for molding the housing 20 in FIG. 12, and the same parts are denoted by the same reference numerals as in FIG. FIG.
In FIG. 3, the lower mold 25 has a support 2 shown in FIG.
A molding cavity 30 corresponding to the contour of the housing 20 having the substrate 10, the holding member 11 and the like is provided, and positioning pins 31, 49 and a core pin 32 are provided so as to face the cavity 30. Reference numeral 33 denotes an extruding plate, which is provided with an extruding pin 34 having a tip portion which coincides with the contour of the cavity 30 or slightly protrudes into the cavity 30, and includes an extruding rod 35 and a returning rod 36. Provide. Other configurations are the same as those shown in FIG.

An embodiment in which the housing 20 which is a component of the swing type actuator of the present invention is formed by using the injection mold having the above-described structure will be described. First, the permanent magnet 3
The lower yoke 38 is inserted into the cavity 30 in a state where the lower yoke 38 is adsorbed to the rear surface of the cavity. In this case, the positioning in the horizontal direction is performed by the positioning pin 31, the positioning in the vertical direction is performed by the positioning pin 49 and the pushing pin 34, and the permanent magnet assembly including the permanent magnet 3 and the lower yoke 38 is inserted into the cavity 30. Is set at a predetermined position.

Next, when the movable mold 22 is set on the fixed mold 21 via the guide pins 24 and the guide holes 23, the front ends of the positioning pins 37 abut on the back surface (the upper surface in FIG. 13) of the lower yoke 38. The permanent magnet 3 and the lower yoke 38 are prevented from floating due to the molding pressure during injection molding. In this state, if a hot melt of polyphenylene sulfide resin containing glass fiber is injected and filled into the cavity 30 through the sprue 39 and the gate 40, the housing 20 shown in FIG.
Is molded. FIG. 14 is a sectional view of a main part showing an example of the housing 20 in FIG.
2 and FIG. 14, 31a, 37a, 49a and 34a are pin marks of the positioning pins 31, 37 and 49 and the push-out pin 34 shown in FIG.
Formed in a part of Such pin marks 31a, 37
If a, 49a and 34a are present, there is a risk that burrs may fall off and foreign matter may be deposited. The lower yoke 38
Is usually formed of a steel material such as soft iron or mild steel, and the permanent magnet 3 is formed of, for example, an Nd—Fe—B based magnet material, and is used without being subjected to surface treatment such as plating for cost reduction. In this case, since the lower yoke 38 and the permanent magnet 3 rust when exposed to the atmosphere, the pin marks 31 are formed as follows in the present invention.
a, 37a, 49a and 34a to the closing members 41, 4
2, 43 and 44 are filled. That is, the support 2, the substrate 10
The housing 20 is housed in a mold provided with a cavity corresponding to the contour of the holding member 11, and the thermoplastic resin is filled in the pin marks 31a, 37a, 49a, and 34a to form the closing members 41 to 44. is there.

In the above embodiment, an example was described in which the periphery of the holding member 11 integrally projecting from the substrate 10 was formed continuously. However, the holding member 11 may be formed in a discontinuous shape or a plurality of protrusions. The operation is the same, that is, it is sufficient to have a function of holding and fixing the permanent magnet assembly 13. Note that another permanent magnet is provided in the upper yoke 14 so that the lower yoke 38
May be configured to be opposed to the permanent magnet 3 provided in the above. The means for fixing the upper yoke 14 to the column 2 is not limited to the set screw 2a, but may be, for example, a rivet-shaped one that is driven or press-fitted and fastened.
Further, in this embodiment, the actuator for the magnetic head has been described. However, the function is the same even if the functional member to be provided at one end of the arm is not only the magnetic head but also an optical head or the like.

[0056]

Since the present invention has the above-described structure and operation, by molding most of the components of the magnetic circuit integrally, the number of components can be greatly reduced, and the assembling work can be performed. As a result, the productivity can be greatly improved, and as a result, the production cost can be significantly reduced. Further, by integrating most of the constituent members, there is an effect that the size and thickness of the entire swing type actuator can be reduced.

[Brief description of the drawings]

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

FIG. 2 is a longitudinal sectional view of an essential part showing an example of an injection mold for molding the housing 20 shown in FIG.

FIG. 3 is an exploded perspective view showing components of a magnetic circuit according to a second embodiment of the present invention.

FIG. 4 is a main part plan view showing an example of a housing 20 according to a second embodiment of the present invention.

FIG. 5 is a sectional view taken along line BB in FIG. 4;

FIG. 6 is a perspective view showing a magnetic circuit according to a third embodiment of the present invention.

FIGS. 7A and 7B are enlarged cross-sectional views of a main part showing the vicinity of an end of the column 2 in FIG. 6, wherein FIG. 7A shows a state before fixing and FIG. 7B shows a state after fixing.

FIG. 8 is a perspective view showing a magnetic circuit according to a fourth embodiment of the present invention.

FIG. 9 is an enlarged perspective view showing the vicinity of the end of the support column 2 in FIG.

FIG. 10 shows a housing 20 according to a fifth embodiment of the present invention.
FIG.

11 is a sectional view taken along line CC in FIG.

FIG. 12 is an exploded perspective view showing constituent members of a magnetic circuit according to a sixth embodiment of the present invention.

13 is a vertical sectional view of an essential part showing an example of an injection mold for molding the housing 20 in FIG.

FIG. 14 is a sectional view of a main part showing an example of a housing 20 in FIG.

15A and 15B are explanatory views of a main part showing an example of a conventional swing type actuator, wherein FIG. 15A is a partially broken plane, and FIG. 15B is a view in the direction of arrow A in FIG.

FIG. 16 is a perspective view of relevant parts showing constituent members of the magnetic circuit in FIG. 15;

FIG. 17 is an exploded perspective view showing constituent members in FIG. 16;

[Explanation of symbols]

 2 Support 3 Permanent magnet 10 Substrate 11 Holding member 14 Upper yoke 16 Buffer member 17, 18 Locking portion 38, 46 Lower yoke 47 Auxiliary yoke 48 Coating

 ──────────────────────────────────────────────────続 き Continued on front page (31) Priority claim number Japanese Patent Application No. 4-166530 (32) Priority date June 25, 1992 (1992.6.25) (33) Priority claim country Japan (JP) (31) Priority claim number Japanese Patent Application No. 4-166531 (32) Priority date June 25, 1992 (1992.6.25) (33) Priority claim country Japan (JP) (31) Priority claim number Japanese Patent Application No. 5-21034 (32) Priority date February 9, 1993 (1993.2.9) (33) Priority claiming country Japan (JP)

Claims (7)

(57) [Claims] 1. A housing in which a permanent magnet is fixed to at least one of a pair of yokes provided facing each other, a magnetic gap is formed on the surface of the permanent magnet, a movable coil is provided at one end, and a functional member is provided at the other end. Are fixed to each other, and are formed so as to be swingable. A swinging type actuator in which a movable coil is movable along the surface of the permanent magnet in the magnetic gap is provided. Supports located near both sides of the member are erected and a housing is formed by integrally molding at least the substrate, the holding member and the support with a thermoplastic resin material, and magnetized in the thickness direction to form a flat plate. The permanent magnet assembly formed by the permanent magnet formed in (1) and the lower yoke made of a ferromagnetic material adsorbed on the back surface of the permanent magnet An upper yoke which is integrally fixed to be held by a holding member and is formed of a ferromagnetic material so that the permanent magnet can be included in a contour projected onto a plane; An oscillating-type actuator, wherein the oscillating-type actuator is fixed to a surface. 2. A housing having a permanent magnet fixed to at least one of a pair of yokes provided facing each other, a magnetic gap formed on a surface of the permanent magnet, a movable coil at one end, and a functional member at the other end. Are fixed to each other, and are formed so as to be swingable. A swinging type actuator in which a movable coil is movable along the surface of the permanent magnet in the magnetic gap is provided. Supports located near both sides of the member are erected and a housing is formed by integrally molding at least the substrate, the holding member and the support with a thermoplastic resin material, and magnetized in the thickness direction to form a flat plate. The permanent magnet assembly formed by the permanent magnet formed in (1) and the lower yoke made of a ferromagnetic material adsorbed on the back surface of the permanent magnet It is fixed integrally so as to be held by the holding member, and the positioning pin mark formed on the back surface of the lower yoke is filled with a closing member made of a thermoplastic resin by molding means, and the ferromagnetic material is used to fill the projected contour onto a plane. An oscillating-type actuator, wherein an upper yoke formed so as to be able to contain the permanent magnet is fixed to the support via a gap with the surface of the permanent magnet. 3. A housing in which a permanent magnet is fixed to at least one of a pair of yokes provided facing each other, a magnetic gap is formed on the surface of the permanent magnet, a movable coil is provided at one end, and a functional member is provided at the other end. Are fixed to each other, and are formed so as to be swingable. A swinging type actuator in which a movable coil is movable along the surface of the permanent magnet in the magnetic gap is provided. Supports located near both sides of the member are erected and a housing is formed by integrally molding at least the substrate, the holding member and the support with a thermoplastic resin material, and magnetized in the thickness direction to form a flat plate. The permanent magnet assembly formed by the permanent magnet formed in (1) and the lower yoke made of a ferromagnetic material adsorbed on the back surface of the permanent magnet An upper yoke which is integrally fixed to be held by a holding member and is formed of a ferromagnetic material so that the permanent magnet can be included in a contour projected onto a plane; A rocking-type actuator which is fixedly attached to a column by being inserted into the column and forming a locking portion by thermal melting at an end of the column. 4. A housing in which a permanent magnet is fixed to at least one of a pair of yokes provided facing each other, a magnetic gap is formed on the surface of the permanent magnet, a movable coil is provided at one end, and a functional member is provided at the other end. Are fixed to each other, and are formed so as to be swingable. A swinging type actuator in which a movable coil is movable along the surface of the permanent magnet in the magnetic gap is provided. A column located near both sides of the member is erected, and a locking portion is formed at an end of the column so that the diameter can be reduced. At least the substrate, the holding member, and the column are integrally formed of a thermoplastic resin material. A permanent magnet formed into a flat plate by magnetizing in the thickness direction to form a housing
A permanent magnet assembly formed by a lower yoke made of a ferromagnetic material adsorbed on the back surface of the permanent magnet is integrally fixed so as to be held by the holding member when the housing is formed, and is formed by a ferromagnetic material. An upper yoke provided with a locking hole formed so that the permanent magnet can be included in the outline of the projection and having an inner diameter smaller than the outer diameter of the locking portion. An oscillating actuator characterized in that it is fixed to said support column through a gap with the surface of a permanent magnet by being fitted to a stop. 5. A housing having a permanent magnet fixed to at least one of a pair of yokes provided facing each other, a magnetic gap formed on the surface of the permanent magnet, a movable coil at one end, and a functional member at the other end. Are fixed to each other, and are formed so as to be swingable. A swinging type actuator in which a movable coil is movable along the surface of the permanent magnet in the magnetic gap is provided. Supports located near both sides of the member are erected and a housing is formed by integrally molding at least the substrate, the holding member and the support with a thermoplastic resin material, and magnetized in the thickness direction to form a flat plate. , A flat lower yoke made of a ferromagnetic material adsorbed on the back surface of the permanent magnet, and a projecting end of the lower yoke made of a ferromagnetic material. A permanent magnet assembly formed by the auxiliary yoke is held by the holding member during molding of the housing, and is integrally fixed so as to include the auxiliary yoke in the support, and is projected onto a plane by a ferromagnetic material. An oscillating-type actuator, wherein an upper yoke formed so as to be able to include the permanent magnet in a contour is fixed to the column through a gap with the surface of the permanent magnet. 6. A housing in which a permanent magnet is fixed to at least one of a pair of yokes provided facing each other, a magnetic gap is formed on the surface of the permanent magnet, a movable coil is provided at one end, and a functional member is provided at the other end. Are fixed to each other, and are formed so as to be swingable. A swinging type actuator in which a movable coil is movable along the surface of the permanent magnet in the magnetic gap is provided. Supports located near both sides of the member are erected and a housing is formed by integrally molding at least the substrate, the holding member and the support with a thermoplastic resin material, and magnetized in the thickness direction to form a flat plate. The permanent magnet assembly formed by the permanent magnet formed in (1) and the lower yoke made of a ferromagnetic material adsorbed on the back surface of the permanent magnet An upper yoke held by a holding member and integrally fixed so as to cover the surface of the permanent magnet, and formed by a ferromagnetic material so that the permanent magnet can be included in a projected contour onto a plane; A rocking-type actuator fixed to the support via a gap between the surface of the actuator and the support. 7. The oscillating actuator according to claim 1, wherein a buffer member made of an elastic resin material is fixed to at least a portion of the outer periphery of the column facing the arm by molding means.