JPH0454856A - Voice coil motor - Google Patents

Abstract

PURPOSE:To provide a coil with a low inductance and thin size so as to make high speed seek action possible by forming a coil holding member of conductive metal. CONSTITUTION:A coil holding unit 21 is fixed to one end part and a coil holding unit 22 or 23 is fixed to the other end part, of a carriage main unit 20. In the coil holding member 21, a base part 21a and arm parts 21b, 21c in both ends of the base part are integrally molded by copper or aluminum of conductive material to apply anodic oxidation treatment to the surface, and lowness of inductance of a coil and thinness in size of a coil, because of no necessity for a short ring, can be attained. When a current is allowed to flow in the coils 24, 25, a carriage 30 is guided by a guide rail to make a reciprocating motion in accordance with a direction of the current, and an optical head 29 makes a reciprocating motion in a radial direction of a disk medium.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a voice coil motor, and particularly to a voice coil motor that drives the movement of a head of a disk device.

In order to enable high-speed seek operations, the voice coil motor that drives the movement of the head in a disk drive is required to have 1) high thrust, 2) low coil inductance, and 2) high rigidity of the coil installation.

[Conventional technology]

As shown in FIG. 6, in a conventional voice coil motor, a voice coil 12 is formed by winding a coil 11 around a short ring 10 formed into a cylindrical shape made of copper or aluminum, and the inductance of the coil 11 is equalized by the short ring IO. It has been significantly lowered.

[Problem to be solved by the invention]

In the conventional voice coil motor, since the short ring 10 is used, the height (outer diameter) H of the voice coil 12 becomes large, and there is a problem that it cannot be made thinner. Since the holding member that is held and attached to the carriage is made of resin to reduce weight, it lacks rigidity and has a low mechanical resonance frequency, which hinders high-speed seek operations.

The present invention has been made in view of the above points, and an object of the present invention is to provide a voice coil motor capable of high-speed seek operation by reducing the inductance and thickness of the coil.

[Means to solve the problem]

The voice coil motor of the present invention uses permanent magnets to form a magnetic field perpendicular to the longitudinal direction of the yoke, passes current through the coil inserted through the yoke, gives the coil a thrust in the longitudinal direction of the yoke, and Drives carriage movement.

The coil is fixed to the carriage by a coil holding member made of conductive metal.

[Effect]

In the present invention, since the coil holding member is made of conductive metal, the inductance of the coil can be reduced without using a short ring as in the past, and the coil can be made thinner because a short ring is not required. becomes. In addition, the coil holding member is made of metal and has increased rigidity compared to conventional resin-made members, and the mechanical resonance frequency increases, eliminating resonance in the low frequency band and enabling high-speed seek operation.

〔Example〕

FIG. 1 shows an exploded perspective view of a carriage of a disk device to which the voice coil motor of the present invention is applied.

In the figure, 20 is a carriage body, and in the case of a magneto-optical disk device, an optical head is housed within this carriage body 20. A coil holder 21 is fixed to one end 20a of the carriage body 20, and a coil holder 22 or 23 is fixed to the other end 20b.

The coil holding member 21 has a base portion 21a and arm portions 2 at both ends of the base portion 21a.
1b and 21c are integrally molded from a conductive material such as copper or aluminum, and the surface is anodized.
1b and 21c each have an opening 21e facing each other.
, 21f are provided, and the coil is held and held by the arm portions 21b and 21c with both edges aligned with the openings 21e and 21f.

The coil holding member 22 has a base portion 22a and arm portions 2 at both ends of the base portion 22a.
2b, 22c and a horizontal frame 22d connecting the ends of the arm parts 22b, 22c are integrally molded from a conductive material such as copper or aluminum, and the surface is anodized. The openings 2 are facing each other.
The coil is attached to the arm portion 22 with both edges aligned with 2e and 22f.
b and 22c are clamped and held.

The coil holding member 23 is attached to the base 2 similarly to the coil holding body 21.
3a and arm parts 23b and 23c at both ends thereof are integrally molded from a conductive material such as copper or aluminum, and the surfaces are anodized, and each of the arm parts 23b and 23c has an opening 23e facing each other. , 23f are provided, and this opening 23e.

With both edges aligned with 23f, the coil is attached to arm portions 23b and 2.
It is clamped and held by 3c.

The coil holding members 21 and 2 are attached to the carriage main body 20 described above.
2 (or 23) is fixed, and the carriage 30 is assembled as shown in the plan view of FIG. 2(A). Coils 24 and 25 are held in each of the coil holding members 21 and 22 (or 23), and rollers 26 and 2 are held in the carriage body 20.
7° 28 and an optical head 29 are provided.

This carriage 30 is attached to a disk device shown in the sectional view of FIG. 2(B). In the figure, guide rails 33.34 fixed to the frame 31.32 of the disk device
Rollers 26 and 27, 28 of the carriage are respectively guided. Each of the frames 31 and 32 has a yoke 35.
36 are fixed, and permanent magnets 37 and 38 are fixed to each of the yokes 35 and 36, and the permanent magnets 37 and 38
The outer peripheral surfaces of the coils 24 and 25 of the carriage 30 are opposed to each other. Both longitudinal ends of the yoke 35 (and 36) are bent as shown in the cross-sectional view of FIG.
(and 25) are connected to the yoke 41 (and 42) inserted through the openings 21e and 21f (and 22e and 22f) of the coil holding member 21 (and 22).

When current is applied to the coils 24 and 25, the carriage 30 is guided by the guide rails 33, 34 and performs reciprocating motion depending on the direction of the current, thereby causing the optical head 29 to move as shown by the two-dot chain line in FIG. 2(B). The disk medium 45 is reciprocated in the radial direction.

Here, the inductance/frequency characteristics at both ends and the center of the coil held by a resin coil holding member as in the past are shown by solid lines Ia, Ib, and Ic in Fig. 4, respectively, and at a frequency of IKHz. While the inductance of each part is 18 to 21 mH, when the coil holding member 21 of the present invention holds the same coil 24 as the conventional one, the inductance in the arm parts 21b, 21c and in the central part between both arm parts is large.・The frequency characteristics are shown by the solid line I [a, I
As shown in Ib and πC, the inductance of each part is halved to approximately 9 mH at a frequency of IKHz.

In this way, since the coil holding members 21, 22, and 23 are made of conductive metal, it is possible to reduce the inductance of the fill without using a short ring as in the past.
Since a short ring is not required, the coil can be made thinner. In addition, the coil holding members 21, 22, and 23 are made of metal and have increased rigidity compared to conventional resin ones, increasing the mechanical resonance frequency and eliminating resonance in the low frequency band, enabling high-speed seek operation. .

〔Effect of the invention〕

As described above, according to the voice coil motor of the present invention, the low inductance of the coil enables high-speed seek operation, the coil can be made thinner, and the mechanical resonance of the coil holding member including the coil can be reduced. It is possible to increase the frequency and enable high-speed seek operations, which is extremely useful in practice.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view of an embodiment of the carriage of a disk device to which the motor of the present invention is applied, FIG. 2 is a plan view of the carriage and a sectional view of the disk device, and FIG. 3 is a cross-sectional view of the voice coil motor. FIG. 4 is a characteristic diagram of a coil of a conventional motor, FIG. 5 is a characteristic diagram of a coil of a motor of the present invention, and FIG. 6 is a perspective view of an example of a coil of a conventional motor. 20... Carriage body, 21-23... Coil holding member, 24.25... Coil, 33.34... Guide rail, 35, 36, 41.42... Yoke, 3
7.38...Permanent magnet. Figure 1

Claims (1)

[Claims] A permanent magnet forms a magnetic field perpendicular to the longitudinal direction of the yoke, and a current is passed through a coil inserted through the yoke to apply a thrust in the longitudinal direction of the yoke. 1. A voice coil motor for driving movement of a voice coil motor, characterized in that the coil is fixed to the carriage by a coil holding member made of a conductive metal.