JP2935651B2 - Swing type actuator for magnetic disk drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an improvement of a swing type actuator of a magnetic head in a magnetic disk drive.

[0002]

2. Description of the Related Art In a magnetic disk drive, for example, a magnetic head held at the tip of an actuator is moved by a swing type actuator that swings about a rotation axis to position the magnetic head with respect to a recording track on a rotary disk. Do.

[0003] In such a disk drive, a so-called contact start / stop system is adopted in most cases in order to simplify the mechanism.

Japanese Patent Application Laid-Open No. 4-229062 discloses such an actuator for a magnetic head.
There is disclosed an actuator in which an actuator is integrally formed of a thermoplastic plastic to reduce the weight and cost of the actuator.

[0005]

However, in the above-described contact start / stop method, friction occurs due to contact between the magnetic head and the rotating disk, so that static electricity is generated in the magnetic head.

In this case, if the actuator is made of a material having low conductivity, such as plastic, as described above, the magnetic head will be charged. Become. Such discharge generates an irregular electric pulse in the magnetic head, disturbs a normal electric pulse signal at the time of signal recording and reading, and causes a malfunction.

Further, if the entire actuator is formed of plastic, there is a limit to the reduction in thickness, particularly in the arm portion, and there is a problem that it is impossible to cope with the reduction in thickness of the hard disk.

An object of the present invention is to provide an actuator for a magnetic disk drive in which the arm is made thinner while preventing the magnetic head from being charged, by paying attention to such a problem.

[0009]

According to a first aspect of the present invention, there is provided an arm made of a conductive material for supporting a magnetic head, a sleeve made of a conductive material disposed on a base end side of the arm,
Non- locking and holding these arms and sleeves together
A holding member made of a conductive plastic material, the scan
A rotatable support member disposed in the sleeve to rotatably support the holding member.
A rotating shaft, the arm being in contact with the sleeve.
As a result , conduction was made to the rotating shaft side.

In a second aspect of the present invention, the arm is formed of a plurality of thin metal plates stacked at a predetermined interval.

In the first aspect of the present invention, since the conductive arm supporting the magnetic head comes into contact with the conductive sleeve and is electrically connected to the rotating shaft side, the holding member is non-conductive. Despite being plastic, static electricity generated in the magnetic head is released by flowing from the arm to the rotating shaft via the sleeve, and the actuator is properly grounded, thereby ensuring the reliability of the disk drive. Moreover, since the holding member integrally connects the arm and the sleeve by plastic injection molding or the like, the productivity is good and the weight of the entire actuator is reduced.

In the second invention, since the arm is formed of a plurality of thin metal plates laminated at predetermined intervals, the actuator can be made thin without reducing the strength of the arm.
In addition, since the plurality of thin metal plates are integrally connected to and held by the holding member together with the sleeve, even if the arm is made of metal, the stacked state of the arms is firmly maintained, and the entire actuator is reduced in weight and thickness.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a plan view of an actuator 1 according to the present embodiment. FIG. 2 is a sectional view taken along the line AA.

Here, the arm 2 is made of metal. In this embodiment, in particular, the arm 2 has a structure in which three thin metal plates are stacked at a predetermined interval. Here, as the metal thin plate, for example, a stainless steel plate having a thickness of 0.5 mm is used. Such a thin metal plate can be easily formed by, for example, press punching.

As described above, since the arm 2 is made of metal, the arm 2 can be formed thin while maintaining sufficient strength, the dimension of the actuator 1 in the height direction can be reduced, and the entire disk device can be downsized. This is particularly effective when a plurality of arms 2 are used as in the present embodiment.

A mounting hole 4 for the sleeve 3 is formed at the distal end of the arm 2, and a mounting hole 5 for the suspension 11 is formed at the base end on the opposite side. The metal sleeve 3 is fitted into the mounting hole 4,
The arm 2 and the sleeve 3 are electrically connected.

Here, as a method of conduction, a method of making the arm 2 and the sleeve 3 come into direct contact, a method of making contact with a conductive paint, a method of making contact with a conductive adhesive, and the like are also possible. .

Further, in the present embodiment, the sleeve 3 is fitted into the mounting hole 4 of the arm 2, but other forms may be used as long as the arm 2 and the sleeve 3 are electrically connected. Absent.

Here, the sleeve 3 is provided with the bearing 13 interposed therebetween. For example, as shown in FIG. 4, the sleeve 3 has a cylindrical shape in which the bearing 13 can be interposed. By making the sleeve 3 made of metal in this way, durability in the case where the bearing 13 is interposed is ensured. In particular, in the present invention, the fact that the sleeve 3 is made of metal means that the actuator 3 will be described later. 1 is required for grounding.
The form of the sleeve 3 may be, for example, a form having a cutout portion 20 as shown in FIG.

The arm 2, the sleeve 3, and the movable coil 7 are formed so as to be integrally held inside a plastic holding member 6. As a result, the arm 2 and the sleeve 3 are integrally connected with each other while maintaining the electrical continuity due to the metallic connection between the arm 2 and the sleeve 3.

The holding member 6 positions a plurality of laminated arms 2, sleeves 3 and movable coils 7 in a mold for injection molding, for example, and then injects a thermoplastic plastic into the mold. It is formed by doing.

As described above, since the holding member 6 is formed of plastic, the holding member 6 can be manufactured more easily and at lower cost than when formed of another material such as metal or ceramic. Can also be achieved. Further, it is also easy to firmly integrate the arm 2 in which a plurality of thin metal plates are stacked in a stacked manner together with the sleeve 3.

Here, the plastic molding is performed so as to enclose the base end of the arm 2 within a range of 180 degrees or more with respect to the center of the sleeve 3. As a result, the holding member 6 is formed to have sufficient strength, and high durability is maintained with respect to the operation of the actuator 1 while maintaining conduction by the metallic joining of the arm 2 and the sleeve 3.

Further, when there are a plurality of arms 2 as in the present embodiment, this plastic molding is performed so that all the gaps between the arms 2 are filled at the base end of the arm, and the uppermost arm is formed. 2 upper surface and lowermost arm 2
At least a portion of the lower surface of the is covered with plastic.

The interior of the sleeve 3 is not filled with plastic so that the bearing 13 can be installed, and a cavity is maintained.

It is also possible to insert another sleeve between the sleeve 3 and the holding member 6 by coining.

Although an air-core coil may be used as the movable coil 7, a coil having a coil bobbin is effective in preventing deformation of the coil due to injection pressure during molding.

On the other hand, FIG. 3 is a sectional view of the actuator 1 and the like when the actuator 1 thus configured is mounted on the chassis 15 of the magnetic disk drive.

Here, a thin plate-shaped suspension 11 for supporting the magnetic head 10 at the tip thereof is attached to the tip of the adjacent arm 2 so that the magnetic head 10 faces the arm.

The rotating disk 12 has a disk shape.
It is interposed between the magnetic heads 10 facing each other. As a result, the magnetic head 10 is arranged so as to sandwich the rotary disk 12 from both sides.
Writing and reading of data from the rotating disk 12 are performed.

A bearing 13 is provided inside the sleeve 3, and the actuator 1 is rotatably mounted on a rotating shaft 14 provided on a chassis 15 via the bearing 13. Here, the bearing 13, the rotating shaft 14, and the chassis 15 are all formed of a conductive material, and are connected to the actuator 1 through the arm 2 and the sleeve 3.
Will be grounded.

Next, the operation will be described.

The actuator 1 rotates about the rotation shaft 14 by the driving force applied to the movable coil 7, and the magnetic head 10 supported in front of the actuator 1 accesses an arbitrary portion of the rotary disk 12 in the radial direction.

Here, an appropriate magnetic field is formed near the movable coil 7 by a permanent magnet (not shown). When a current is applied to the movable coil 7, a driving force in accordance with Fleming's left hand rule acts on the movable coil 7, and the actuator is actuated. 1
Rotate around the rotation shaft 14.

In this case, since friction occurs between the magnetic head 10 and the rotating disk 12, static electricity is generated in the magnetic head 10. In contrast, in the present invention, since the arm 2 is made of metal, static electricity generated in the magnetic head 10 flows into the arm 2 through the suspension 11. In addition, the arm 2 has a sleeve 3 which is also made of metal.
This static electricity is released to the sleeve 3. Finally, the static electricity is released from the conductive bearing 13 in contact with the sleeve 3 to the chassis 15 through the conductive rotating shaft 14 to which the bearing 13 is fitted, and the actuator 1 is grounded. It will be. As a result, static electricity generated in the magnetic head 10 is not accumulated in the actuator 1 and normal operation of the magnetic head 10 is not hindered. FIG. 3 shows, as an imaginary line, the path of the flow of electricity in this case.

Further, since the arm 2 is formed of a thin metal plate, sufficient strength can be maintained even if the arm 2 is thin, and the holding member 6 integrally connects the arm 2 and the sleeve 3 with plastic. Are firmly supported by the holding member 6. Thereby, the actuator 1 can maintain high reliability in strength and durability during operation.

[0038]

According to a first aspect of the present invention, there is provided an actuator of a disk drive in which a holding member is formed of a non-conductive plastic to reduce the weight and cost of the actuator and to facilitate manufacture thereof. Since the conductive arm supporting the magnetic head comes into contact with the conductive sleeve and is electrically connected to the rotating shaft side, the actuator is suitable even if the holding member is a non-conductive plastic. And the static electricity generated in the magnetic head is appropriately released, so that the reliability of the disk drive is ensured. Moreover, since the holding member integrally connects the arm and the sleeve by plastic injection molding or the like, the productivity is good and the weight of the entire actuator is reduced.

In the second invention, the arm is formed of a plurality of thin metal plates laminated at predetermined intervals in the first invention, so that the actuator can be made thinner without reducing the strength of the arm. In addition, since the plurality of thin metal plates are integrally connected and held by the holding member together with the sleeve, even if the arms are made of metal, the stacked state of the arms is firmly maintained, and the weight and thickness of the entire actuator can be reduced.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a cross-sectional view of the actuator and the like when the actuator according to the embodiment of the present invention is mounted on a chassis of a magnetic disk drive.

FIG. 4 is a perspective view showing a sleeve according to the embodiment.

FIG. 5 is a perspective view showing a sleeve according to another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Actuator 2 Arm 3 Sleeve 6 Holding member 10 Magnetic head 14 Rotation axis

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G11B 21 / 02,19 / 00

Claims (2)

(57) [Claims] 1. An arm made of a conductive material for supporting a magnetic head, a sleeve made of a conductive material disposed on the base end side of the arm, and a non- joint which integrally connects and holds the arm and the sleeve.
A holding member made of a conductive plastic material, and a holding member disposed in the sleeve so that the holding member is rotatable.
A swing type actuator for a magnetic disk drive, comprising: a rotating shaft for supporting the arm; and the arm being in contact with the sleeve to conduct to the rotating shaft side. 2. A swing type actuator for a magnetic disk drive according to claim 1, wherein said arm is formed of a plurality of thin metal plates laminated at a predetermined interval.