JP2003070200A - Coil for actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide coils of a voice coil motor used for a hard disc drive actuator for a computer, etc., which are coated partially or entirely with resin and solidified in a body. SOLUTION: For a turnable actuator which has a suspension 9 with a slider 7 to read or write data at the tip and driving coils 11 to rotate the slider 7, the coils 11 are coated partly or entirely with resin and solidified in a body. The resin used is a synthetic resin coating consisting of a fluorocarbon resin, acrylic resin, urethane resin, or unsaturated polyester, or UV curing resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coil of a voice coil motor used for an actuator of a disk device, for example, a hard disk drive device used in a computer or the like.

[0002]

2. Description of the Related Art An example of conventional technology will be described below with reference to FIGS. An actuator 1 used for a disk device, for example, a hard disk drive device of a computer, includes an arm 5 rotatably supported by a rotary shaft 4 via a bearing 3, and a suspension 9 is provided on one side of the arm 5. The slider 9 is provided at the tip of the suspension 9 to read from and write to the disk. A coil support 13 for holding the coil 11 is provided on the other side of the arm 5 with the rotary shaft 4 interposed therebetween.

When reading information from the disk 15,
The slider 7 attached to the tip of the suspension 9 at the same time as the disk 15 itself rotates at high speed, the slider 9 keeps a constant distance from the surface of the disk 15.
Along with the rotation axis 4, the disk 15 is constantly swung in the radial direction. A voice coil motor is used as a drive source of the actuator 1 for rotating the suspension 9. This voice coil motor
It comprises a coil 11 provided on a coil support 13 on the side opposite to the suspension 9 and a permanent magnet 17 attached to the apparatus main body side. An S pole 17b and an N pole 17a are formed adjacent to each other on an arc.

In such a voice coil motor, when an electric current is passed through the coil 11 provided in the actuator 1, an electromagnetic force acts between the coil 11 and the permanent magnet 17, and as a result, the actuator 1 can rotate. Becomes

The coil 11 provided in the actuator 1 generally has a coil width of 0.1% as shown in FIG.
Approximately 0.5 mm of copper wire or aluminum wire 19 is coated with an insulator 21 such as polyurethane, polyester, or polyesterimide, and is wound by a dedicated winding jig. There is. In order to enhance the adhesion between the adjacent wires, a fusion layer 23 made of a thermoplastic resin is formed on the outer periphery of the insulator in advance, and the adjacent wires are fused by hot air while winding, or after winding, A method is used in which adjacent wires are fused by heating.

[0006]

However, since the actuator 1 having the above-described structure is driven at high speed, breathing resonance or butterfly resonance of the coil occurs on the low frequency side, and the actuator 1 is controlled. There was a possibility of problems.

Generally, the breathing resonance of the coil is
This is due to an electromagnetic force generated when a current is applied to the coil 11 in the coil itself in the outward direction from the center of the rotation axis or in the direction of the center of the rotation axis. The operation will be described below with reference to FIG.

When a counterclockwise (m-direction) current flows through the coil 11, the coil side portion 11a moves clockwise (R direction) due to the electromagnetic force of the coil 11 and the permanent magnet 17.
Is obtained, the actuator 1 rotates clockwise.
Further, since the coil 11 is on the N pole when rotated clockwise, the coil outer side portion 11b receives a force in the outward direction (O direction) from the center of the rotation shaft 4.

On the other hand, when a current in the clockwise direction (n direction) opposite to the above flows in the coil 11, the coil side portion 11a is formed.
Receives a force in the counterclockwise direction (L direction) and the actuator 1 rotates counterclockwise. Further, when rotating in the counterclockwise direction, the coil is positioned on the S pole, so that the coil outer peripheral portion 11b receives a force in the direction (I direction) toward the center of the rotating shaft. Resonance occurs due to the repetition of such operations.

3 and 4 show the results of analysis by the finite element method. FIG. 3 shows the movement of the coil 11 when the actuator 1 receives the force of rotating in the clockwise direction, and FIG. 4 shows the movement of the coil 11 when the actuator 1 receives the force of rotating in the counterclockwise direction. The movement of the coil 11 is shown. According to this analysis result, when the actuator 1 receives a force to rotate clockwise or counterclockwise, the coil outer side portion 11b moves outward or around the rotary shaft 4 as described above. 4 It can be seen that the force is applied in the central direction.

The other butterfly resonance is caused by the structure of the actuator 1. Figure 5
Is an example of analyzing the structure of a general actuator 1 using the finite element method. From this analysis result, it can be seen that the coil support 13 and the tip of the arm 5 resonate greatly.

In order to avoid the resonance generated on the low frequency side as described above, it is necessary to increase the rigidity of the components constituting the actuator and set the natural frequency on the high frequency side. In order to shift the natural frequency to the high frequency side, there are many factors to be considered such as the composition and shape of the material forming the actuator, but the present invention focuses on the coil 11 provided in the actuator. That is, in the conventional coil, in order to improve the adhesion between the adjacent wires, a fusion layer made of resin is provided on the insulation-coated wires, and the fusion layer is formed into a coil by melting with hot air. Alternatively, a method of melting the coiled material in a high temperature atmosphere in the next step is used. However, due to the fact that the linear velocity when forming the coil is fast and the fusion layer cannot be melted sufficiently, or that sufficient heat is not applied to the center of the cross section of the bundled coils, the adhesion between the wires is insufficient. It was difficult to increase the rigidity.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of the conventional problems as described above. A rotatable actuator having a driving coil for moving is characterized in that the coil is entirely or partially coated with a resin and integrally solidified.

[0014]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described below with reference to FIG. FIG. 6 is a schematic explanatory view and a sectional explanatory view of the coil after resin coating. As for the internal coil, as in the conventional case, a wire 19 such as a copper wire or an aluminum wire having a thickness of about 0.1 to 0.5 mm is coated with an insulator 21 such as polyurethane, polyester or polyester imide, and the insulation is performed. A fusion bonding layer 23 made of a thermoplastic resin is formed on the outer periphery of the body, and a winding wire for a dedicated winding jig is simultaneously blown with hot air to improve the adhesion between adjacent wires, or a dedicated winding wire After being wound around a jig, the entire coil is heated in an oven or the like to improve the adhesion between adjacent wires.

In order to improve the adhesion between the adjacent wires, the coil is dipped in a molten resin and pulled up, so that the resin 25 is attached to the outermost circumference of the coil as an outermost circumference coating layer to be integrated. Has solidified. Therefore, the rigidity of the coil itself can be further increased by the synergistic effect of the adhesion between the adjacent wires by performing the conventional method and the reinforcement by covering the entire outer peripheral surface of the coil with the resin 25 and solidifying the resin. It will be possible.

As the resin 25, a synthetic resin paint such as a fluororesin-based resin, an acrylic resin-based resin, a urethane resin-based resin, an unsaturated polyester-based resin, or an ultraviolet curable resin is used.
The viscosity of the resin 25 is preferably in the range of 5 to 10 Pa · s for the purpose of preventing bubbles from being mixed between the coil and the resin and keeping the thickness of the resin attached to the coil constant. . Further, in the present embodiment, the method of immersing the coil in the molten resin has been described, but the same applies when the coil is put in a mold to attach the resin or the resin is sprayed on the coil. You can get Further, in the present embodiment, the method of adhering the resin to the entire coil has been described. It is possible.

Table 1 shows an example of experimental results according to this embodiment.

[0018]

[Table 1] Samples 1 and 2 were coated with synthetic resin paint and UV curable resin on the entire outer circumference of the coil, and Sample 3 was a resin manufactured by the conventional method without applying resin, and the deflection of the coil was evaluated for each sample. It was done. As a measuring method, as shown in FIG. 7, the load when the deflection amount of the center line of the coil reaches a certain distance (y) is measured. From these experimental results, it can be seen that in both Samples 1 and 2, the load until the amount of deflection reaches the constant distance (y) is improved as compared with the conventional product.

[0019]

The effect of the present invention is that after the coil is formed, the resin is applied to the entire coil and integrally solidified, whereby the rigidity of the coil itself is increased, and as a result, the resonance point of the actuator itself can be shifted to the high frequency side. Therefore, the conventional problems described above can be solved.

[Brief description of drawings]

FIG. 1 is an actuator cross-sectional explanatory view.

FIG. 2 is an explanatory diagram of an actuator principle.

FIG. 3 is a diagram showing a finite element method analysis result when an actuator rotates clockwise.

FIG. 4 is a diagram showing a finite element method analysis result when the actuator rotates counterclockwise.

FIG. 5 is a diagram showing a finite element method analysis result of butterfly resonance.

FIG. 6 is a schematic explanatory view and a cross-sectional explanatory view of an embodiment.

FIG. 7 is an explanatory diagram of a deflection amount evaluation method.

[Explanation of symbols] 1: Actuator 3: Bearing 4: Rotation axis 5: Arm 7: Slider 9: Suspension 11: coil 11a: Side of coil 11b: Outer edge of coil 13: Coil support 15: Disc 17: Permanent magnet 17a: N pole 17b: S pole 19: Wire 21: Insulator 23: Fusing layer 25: Resin

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 5D068 AA01 BB01 CC12 EE19 GG25                 5H603 AA03 BB01 BB14 CA02 CA05                       CB01 CB22 CB23 CB25 CC14                       CC19 CD13 CD21 CD32 CE01                       CE13 CE14 EE09 EE10 FA08                       FA18 FA20 FA22 FA26                 5H604 AA05 BB01 BB11 CC02 CC04                       CC20 DA16 DA18 DA23 DB03                       DB05 DB19 PB01 PB02 PB04                       PE06                 5H633 BB02 GG06 GG09 GG16 HH02                       HH08

Claims (2)

[Claims] 1. A rotatable actuator equipped with a suspension having a slider for reading and writing data at its tip and a drive coil for rotating the slider, wherein the coil has an entire circumference or a part thereof. A coil for an actuator, characterized in that the coil is integrally solidified by coating a resin on the coil. 2. The coil for an actuator according to claim 1, wherein the resin is a synthetic resin paint made of a fluororesin type, an acrylic resin type, a urethane resin type, or an unsaturated polyester type, or an ultraviolet curable resin.