JPH04302872A - Assembly structure of carriage arm driving mechanism - Google Patents

Abstract

PURPOSE:To prevent a top yoke from inclining and to facilitate assembly work and to enhance working efficiency by providing a supporting part on a device pedestal close to one part position of the top yoke on the side of a bottom yoke. CONSTITUTION:The bottom yoke 21 and a swing arm 11 are fitted to the device pedestal, and the top yoke 23 is placed on a side yoke. At this time, the yoke 23 is moved on the side of a projecting part 23a to the side of the yoke 21 to be inclined by a gap (t) by attraction force of a magnet 17, but the further inclination is prevented. As a result, a collision between the magnet 17 and the arm 11 does not occur, so as to prevent both parts from being damaged. Then, the gap (t) is formed after assembling the yoke 23 with the yoke 21, and the yoke 23 can be maintained with its prescribed distance from the yoke 21. In addition, the need of lifting and holding the yoke 23 at the time of the assembly work is eliminated.

Description

[Detailed description of the invention]

[Object of the invention]

0002

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an assembly structure for a drive mechanism for moving a carriage arm equipped with a magnetic head.

0003

2. Description of the Related Art FIG. 3 is a plan view schematically showing the internal structure of, for example, a magnetic disk drive having this type of carriage arm drive mechanism assembly structure. A magnetic disk 1, which is a recording medium, is driven by a spindle motor 5 mounted on a device base 3.
rotates at high speed. The magnetic head 7 that records and reproduces information on the magnetic disk 1 has a support spring mechanism 13 on the tip side of a swing arm 11 as a carriage arm that rotates with respect to the device base 3 about a central axis 9. It is attached through.

A coil 15, which is part of a voice coil motor constituting a drive mechanism for the swing arm 11, is provided on the base end side of the swing arm 11. As shown in FIG. 4, which is an enlarged cross-sectional view of FIG. 3, the coil 1
A magnet 17 is arranged above and close to the magnet 17, and the magnet 17 is attached to a yoke 19 made of a magnetic material that forms a magnetic circuit using magnetic flux generated from the magnet 17. The yoke 19 includes a bottom yoke 21 that is disposed between the device base 3 and the coil 15 and is attached to the device base 3, and a bottom yoke 21 that is attached to the device base 3.
The top yoke 23 is arranged on the opposite side, and a pair of side yokes 25 and 27 (not shown in FIG. 4) are used to attach the top yoke 23 to the bottom yoke 21. One side yoke 25 is composed of a plate-shaped vertical portion that is integrated with the bottom yoke 21, and the other side yoke 27 is composed of a rod-shaped member that stands up from the bottom yoke 21. A screw hole is formed at the upper end of the side yoke 27 of this rod-shaped member, and a screw insertion hole is formed in the top yoke 23 correspondingly, and a screw 29 is inserted through this insertion hole and screwed into the screw hole. The top yoke 23 has a bottom yoke 21 and a side yoke 25.
It will be attached via 27.

[0005]

By the way, the yoke 19 and the magnet 17 need to be placed on the rotation locus of the coil 15 of the swing arm 11 in order to maintain the driving force of the voice coil motor at a predetermined level. It is formed almost in an arc shape. Therefore, the center position Ys of the side yokes 25 and 27 that support the top yoke 23 is considerably shifted toward the center axis 9 side when viewed from the top yoke 23 as a whole, whereas the center position Ms of the attraction force of the magnet 17 is , is shifted to the side opposite to the center axis 9 with respect to the center position Ys of the side yokes 25 and 27.

For this reason, the bottom yoke 21 is attached to the device base 3.
After attaching the swing arm 11 to the device base 3 via the central shaft 9, when assembling the top yoke 23 to the bottom yoke 21 using the screws 29, the top yoke 23 is attached to the side yokes 25, 27. When placed on top, the top yoke 23, which is closer to the center position Ms of the attraction force of the magnet 17 than the center position Ys of the side yokes 25 and 27, moves as shown by arrow B in FIG. 4 due to the attraction force of the magnet 17 to the bottom yoke 21. It moves toward the bottom yoke 21 and tilts as shown by the two-dot chain line.

The attraction force of the magnet 17 is quite strong, so when it is tilted, the magnet 17 collides with the swing arm 11 and gives a shock, which may break the magnet 17 or damage the swing arm 11. The dust generated during this process may be taken into the device, causing
There is a possibility that the recording/reproducing operation of the magnetic head on the magnetic disk may be hindered. In order to prevent such tilting of the top yoke 23, it is necessary to carry out the assembly work while lifting and holding the top yoke 23, which results in extremely poor work efficiency.

Therefore, if the center position Ys of the side yokes 25, 27 is brought closer to the center position Ms of the attraction force of the magnet 17, the above problem can be solved to some extent, but the positions of the side yokes 25, 27 are After considering the rotation range of the swing arm 11, it is installed as close as possible to the center position Ms of the attraction force of the magnet 17 within the limited space inside the device, and the side yoke is 25 and 27 toward the center position Ms is virtually impossible.

SUMMARY OF THE INVENTION An object of the present invention is to improve the ease of assembling a top yoke to a bottom yoke.

[Configuration of the invention]

[0011]

Means for Solving the Problems In order to achieve the above object, the present invention includes a movable carriage arm for moving a magnetic head over a recording medium and positioning it at a predetermined information track position. The driving mechanism for moving the carriage arm includes a coil provided on the carriage arm, a magnet placed close to the coil, and a yoke provided on the device base with the magnet attached to form a magnetic circuit by magnetic flux generated from the magnet. The yoke consists of a bottom yoke that is placed between the device base and the coil and is attached to the device base, and a top yoke that is placed on the opposite side of the coil to the bottom yoke and is attached to the bottom yoke. A supporting portion is provided on the device base, and the supporting portion is disposed close to at least one portion of the top yoke on the bottom yoke side in a state where the top yoke is attached to the bottom yoke.

0012

[Operation] In such an assembly structure of the carriage arm drive mechanism, when assembling the top yoke to the bottom yoke, if the top yoke is placed on the bottom yoke, the top yoke will move toward the bottom yoke due to the magnetic attraction force. A force is applied to move the top yoke, but at this time, a portion of the top yoke comes into contact with the support portion on the device base side to prevent the top yoke from tilting.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view schematically showing the internal structure of a magnetic disk drive according to an embodiment of the present invention, and FIG. 2 is an enlarged sectional view taken along line CC in FIG. Here, the same components as in FIGS. 3 and 4 are given the same reference numerals. As shown in FIG. 1, the top yoke 23 of the voice coil motor that rotates the swing arm 11 in this magnetic disk device has a protrusion 23a that protrudes leftward in the figure with respect to the bottom yoke 21. Part 23a
On the device base 3, facing the bottom yoke 21 side surface,
A top yoke support protrusion 31 serving as a support portion is integrally molded.

When the top yoke 23 is assembled to the bottom yoke 21, the top yoke support protrusion 31
A slight gap t is formed between the top yoke 23 and the lower surface of the top yoke 23. In assembling the top yoke 23, first the bottom yoke 21 and the swing arm 11 are sequentially attached to the device base 3, and then the top yoke 23 is placed on the side yokes 25 and 27. At this time, magnet 17
Due to the suction force of the top yoke 23, the side yoke 2
The center position Ms side of the attraction force of the magnet 17 receives a force that tends to approach the bottom yoke 21 from the center position Ys of the magnets 5 and 27. As a result, the protrusion 23a side of the top yoke 23 moves toward the bottom yoke 21 and is slightly inclined by an amount corresponding to the gap t, but the lower surface of the protrusion 23a contacts the upper end of the top yoke support protrusion 31 and the top yoke 2
3 large tilts are prevented.

As a result, collision of the magnet 17 with the swing arm 11 is avoided, and as a result, the magnet 17
breakage and damage to the swing arm 11 are prevented. Thereafter, the top yoke 23 is assembled to the bottom yoke 21 by tightening the screws 29. After assembly, a gap t is formed between the lower surface of the protrusion 23a of the top yoke 23 and the top yoke support protrusion 31.
The top yoke 23 is maintained at a predetermined distance from the bottom yoke 21, resulting in a good assembled condition.

By preventing damage to the magnet 17 and the swing arm 11, the generation of dust is avoided, so that there is no adverse effect on the recording/reproducing operation of the magnetic head on the magnetic disk due to dust being taken into the device. Prevented. Also, during assembly work, the top yoke support protrusion 31 supports the top yoke 23, so
It is no longer necessary to lift and hold the top yoke 23, improving work efficiency.

In the above embodiment, the magnet 17 is attached to the top yoke 23, but the magnet 17 is attached to the bottom yoke 21, or the top yoke 23 and the bottom yoke 2 are attached.
The present invention may be applied to devices that are attached to both. In addition to the swing arm 11 that rotates, the carriage arm may be a slide arm that moves linearly.

[0019]

As described above, according to the present invention, when the top yoke is attached to the bottom yoke, the support portion disposed close to at least one portion of the top yoke on the bottom yoke side can be attached to the device base. Because it is installed on the stand, when assembling the top yoke to the bottom yoke,
Even if the top yoke is placed on the bottom yoke and a force is applied to the top yoke to move toward the bottom yoke due to the attraction force of the magnet, a part of the top yoke will be attached to the support on the device base side. This can prevent a large tilt of the top yoke by contacting the top yoke. This makes it possible to avoid collision of the top yoke with the swing arm, and eliminates the need to lift and hold the top yoke during assembly work, thereby improving work efficiency.

[Brief explanation of drawings]

FIG. 1 is an enlarged cross-sectional view taken along line C-C of the magnetic disk device shown in FIG. 2 according to an embodiment of the present invention.

FIG. 2 is a cross-sectional plan view showing the internal structure of a magnetic disk device according to an embodiment of the present invention.

FIG. 3 is a plan cross-sectional view showing the internal structure of a conventional magnetic disk device.

FIG. 4 is an enlarged cross-sectional view taken along line AA in FIG. 3;

[Explanation of symbols]

1 Magnetic disk (recording medium) 3 Device base 7 Magnetic head 11 Swing arm (carriage arm) 15
Coil 17 Magnet 19 Yoke 21 Bottom yoke 23 Top yoke

Claims (1)

[Claims] 1. A movable carriage arm for moving a magnetic head over a recording medium and positioning it at a predetermined information track position, and a drive mechanism for moving the carriage arm comprising a coil provided on the carriage arm and a coil provided on the carriage arm. It consists of a magnet placed close to the coil, and a yoke installed on the device base to which the magnet is attached and forms a magnetic circuit using the magnetic flux generated from the magnet. It consists of a bottom yoke placed between and attached to the device base, and a top yoke placed on the opposite side of the coil to the bottom yoke and attached to the bottom yoke, with the top yoke attached to the bottom yoke. ,
An assembly structure for a carriage arm drive mechanism, characterized in that the device base is provided with a support portion disposed close to at least a portion of the top yoke on the bottom yoke side.