JPH08111077A - Actuator latch - Google Patents

Abstract

PURPOSE: To reduce magnetic attracting force of leakage flux from front of a magnetic shield plate to an under yoke as much as possible by interposing a magnetic piece immediately before a movable coil is locked (when the movable coil starts), and immediately after the movable coil was unlocked (when the movable coil operates). CONSTITUTION: Notched part 6 of an under yoke 31b starting from the vicinity of the magnetic shield plate 5 stops the density of the leakage flux from front of the magnetic shield plate 5 to the under yoke 31b to be a low density by having the magnetic piece 3 interposed. The magnetic attracting force acting on the magnetic piece 3 is reduced immediately before the movable coil of a voice coil motor is locked and immediately after the movable coil was unlocked.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an actuator latch provided with a coil lock mechanism for locking a movable coil in a retracted position when the magnetic disk device is not operating.

[0002]

2. Description of the Related Art Conventionally, in a magnetic disk device or the like, the power source is
Then, the carriage in the CSS zone (zone unrelated to the data zone) on the inner circumference side of the disk flies and the magnetic head at the tip moves to the data zone on the outer circumference side of the disk to store or reproduce data. In a magnetic disk device or the like, as shown in FIG. 6, the voice coil motor 31 is moved to lock the magnetic head 21 in a stopped state so that the magnetic head 21 does not move unnecessarily from the CSS zone 22 when the power is turned off. Some use a coil lock mechanism a for locking the coil 31d. This coil lock mechanism a is provided with a magnetic piece 3 on a movable coil 31d of a voice coil motor 31, and drives the voice coil motor 31 obtained by an electromotive current generated by inertial rotation of a disk drive motor (not shown) when the power is turned off. When the carriage 11 is rotated in the inner circumferential direction of the disk by the force and the magnetic head 21 at the tip reaches the CSS zone 22, the latch magnet 4 for magnetically attracting the magnetic piece 3 which is close to the upper side is attached to the voice coil motor 31. It is installed on the lower yoke 31b, and the magnetic shield plate 5 is attached to the side surface of the latch magnet 4 on the rotation direction side of the magnetic piece 3. Originally, the characteristics required for the coil lock mechanism a are that the lock value of the movable coil 31d is as large as possible on the one hand, and on the other hand, the influence of the magnetic attraction force of the latch magnet 4 on the magnetic piece 3 other than the locked position is suppressed. In this respect, in the coil lock mechanism a described above, the required characteristics are satisfied because the magnetic attraction force of the latch magnet 4 is electromagnetically shielded by the magnetic shield plate 5 when unlocked.

[0003]

However, when the magnetic piece 3 is actually locked, the leakage flux 200 reaches the upper yoke 31a via the magnetic piece 3 as shown in FIG. During the period immediately after the release, as shown in FIG. 8, in addition to the leakage flux 200 reaching the upper yoke 31a via the magnetic piece 3, the leakage flux 100 reaching from the front of the magnetic shield plate 5 to the lower yoke 31b with the magnetic piece 3 interposed. To generate. The leakage magnetic flux 100 produces an external force (magnetic attraction force) that hinders the rapid movement of the magnetic piece 3 when the magnetic zone 3 is rotated from the CSS zone 22 to the data zone 12 or when the magnetic zone 3 is rotated from the data zone 12 to the CSS zone 22. In cooperation with the leakage magnetic flux 200, it becomes a factor that makes it difficult to control the seek operation and makes it impossible to record / reproduce data with high accuracy.

The present invention has been made in view of the conventional circumstances, and its technical problem is to provide an actuator latch equipped with a coil lock mechanism immediately before the movable coil is locked (when the movable coil is activated) or when the movable coil is not activated. Until the lock is released (when the movable coil is operating), the magnetic attraction force of the leakage magnetic flux from the front of the magnetic shield plate to the lower yoke is stopped as small as possible through the magnetic piece.

[0005]

[Means for Solving the Problems] Technical means taken to achieve the above-mentioned object are: a movable coil of a voice coil motor or a magnetic piece attached to the rear end of a carriage; and a latch magnet fixed to a lower yoke. , A magnetic shield plate provided on the side surface of the latch magnet on the side of the magnetic piece, the magnetic piece is arranged close to the magnetic shield when the carriage is in a stopped state, and is locked by magnetic attraction of the latch magnet. In the actuator latch provided with the coil lock mechanism, the notch portion starting from the vicinity of the magnetic shield plate is provided in the lower yoke portion along the rotation direction of the magnetic piece.

[0006]

According to the above technical means, the cutout portion of the lower yoke starting from the vicinity of the magnetic shield plate reduces the density of the leakage magnetic flux from the front of the magnetic shield plate to the lower yoke through the magnetic piece. As a result, the magnetic attraction force acting on the magnetic piece is made small just before the movable coil of the voice coil motor is locked or immediately after the lock is released.

[0007]

As described above, the present invention is an actuator latch in which a wide space is formed in the cutout portion in front of the magnetic shield plate for reducing the density of leakage magnetic flux reaching the lower yoke via the magnetic piece. The lock force (magnetic attraction force) of the latch magnet acting on the moving coil during operation is made small and weak. Therefore, it is possible to provide an actuator latch that can obtain stable control without affecting the seek operation by a simple method in which the lower yoke is provided with the cutout portion.

[0008]

Embodiments of the present invention will now be described with reference to the drawings. The drawing shows an actuator latch of the present embodiment, reference numeral A is an actuator latch having a coil lock mechanism a, and 2 is a storage medium set in a magnetic disk device.

The actuator latch A is a voice coil motor (V
CM) 31 is driven to rotate about the shaft 41 to move the magnetic head 21 in the radial direction of the storage medium 2 to store data in the data zone 12 on the outer peripheral side of the storage medium 2 or reproduce the data. Let

The storage medium 2 is provided with a CSS zone (zone unrelated to the data zone) 22 adjacent to the inner side of the data zone 12, and the magnetic head 21 stops on the CSS zone 22 when the power is turned off. , Seek on the data zone 12 when the power is turned on.

A voice coil motor (VCM) 31 for rotating the carriage 11 has a pair of upper and lower yokes 31a, 31.
b, a magnet 31c fixed to the yoke 31b, and a movable coil 31d fixed to the rear end of the carriage 11, which magnet is generated by energization of the movable coil 31d synchronized with turning on the power of the magnetic disk device. 31c
The electromagnetic action causes the carriage 11 to rotate in the radial direction of the storage medium 2 to seek on the data zone 12 as described above, and when the power is turned off, the electromotive current generated from the inertial rotation of the disk drive motor is used. The carriage 11 is rotated in the opposite direction by the obtained driving force, and the CS of the innermost circumference of the storage medium 2 is
The magnetic head 21 is moved to the S zone 22.

It is the coil lock mechanism a that fixes the magnetic head 21 on the CSS zone 22.

This coil lock mechanism a includes a magnetic piece 3 and
Latch magnet 4, magnetic shield plate 5, lower yoke
It is composed of a notch portion 6 provided in 31b.

The magnetic piece 3 is attached to the movable coil 31d of the voice coil motor 31 or the rear end of the carriage 11. In the embodiment, the magnetic head 21 moves to the innermost CSS zone 22 of the storage medium 2. The lower yoke 31b is sometimes attached to a position where it is moved to the vicinity of one end of the lower yoke 31b by rotating.

The latch magnet 4 is the magnetic piece 3 in the above case.
Are fixed to the lower yoke 31b so that they are diagonally adjacent to each other and are permanent magnets.

The magnetic shield plate 5 is adhered and fixed to the side surface on the magnetic piece 3 side so that the magnetic attraction force of the latch magnet 4 acts on the magnetic piece 3 located immediately above and close to it when locked. (Fig. 4). However, when the notch 6 is not provided, the leakage flux 200 reaching the upper yoke 31a through the magnetic piece 3 just before locking and immediately after unlocking as in the above-described conventional example, the magnetic piece 3 is used. Generates a relatively large leakage flux from the front of the magnetic shield plate 5 to the lower yoke 31b, and this leakage flux rotates from the CSS zone 22 to the data zone 12 or from the data zone 12 to the CSS.
A relatively large lock force (magnetic attraction force) is applied to the movable coil 31d when the movable coil 31d is rotated to the zone 22d.
This is one of the factors that interfere with the control during startup and operation. In order to prevent this, the lower yoke 31b is provided with the cutout portion 6.

The notch 6 is formed in the lower yoke 31b along the direction of rotation of the magnetic piece 3, specifically in the outer edge of the lower yoke 31b, with the vicinity of the magnetic shield plate 5 as the starting end. As long as the cutout area starts from the vicinity of the magnetic shield plate 5, the cutout area is free even if it is a part or the entire length of the outer edge of the lower yoke 31b.

Due to the notch 6, the density of the leakage magnetic flux (which will be described with reference numeral 100) from the front of the magnetic shield plate 5 to the lower yoke 31b with the magnetic piece 3 interposed is increased to be a lower density. Therefore, the magnetic attraction force acting on the magnetic piece 3 can be kept small (FIG. 5).

Therefore, during the period immediately before the movable coil 31d is locked or immediately after it is unlocked, specifically, when the movable coil 31d is rotated from the CSS zone 22 to the data zone 12 or from the data zone 12 to the CSS zone 22. Magnetic pieces of time 3
It is possible to weaken the total magnetic attraction force due to the leakage magnetic fluxes 100 and 200 acting on to the extent that the seek operation control is not hindered.

[Brief description of drawings]

FIG. 1 is a plan sectional view of a main part showing a usage state. .

FIG. 2 is a cross-sectional view of the same main portion with the magnetic piece locked, in the same plane.

FIG. 3 is an enlarged view showing the gist of a coil lock mechanism with a magnetic piece locked.

FIG. 4 is an enlarged view showing a coil lock mechanism in a locked state.

FIG. 5 is an enlarged view showing a coil lock mechanism immediately before locking and immediately after unlocking.

FIG. 6 is a plan sectional view showing a usage state of a conventional actuator latch.

FIG. 7 is an enlarged view showing a coil lock mechanism in a locked state.

FIG. 8 is an enlarged view showing the coil lock mechanism immediately before locking and immediately after unlocking.

[Explanation of symbols]

A: Actuator latch 31: Voice coil motor 11: Carriage 3: Magnetic piece 31d: Moving coil 5: Magnetic shield plate 4: Latch magnet a: Coil lock mechanism 6: Notch 31b: Lower yoke

Claims (1)

[Claims] 1. A magnetic piece attached to a movable coil of a voice coil motor or a rear end of a carriage, a latch magnet fixed to a lower yoke, and a magnetic shield plate provided on a side surface of the latch magnet on the magnetic piece side. Rotation of the magnetic piece in an actuator latch that is configured and has a coil lock mechanism that locks by magnetic attraction of a latch magnet when the magnetic piece is arranged close to the magnetic shield plate when the carriage is stopped. An actuator latch characterized in that a notch portion starting from the vicinity of a magnetic shield plate is provided in a lower yoke portion along the direction.