JPH0785581A - Magnetic disk unit - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to provide a magnetic disk device capable of ensuring a sufficient starting torque even when a small spindle motor is adopted. A housing (4), a magnetic disk (2) rotatably housed in the housing (4), a spindle assembly (6) having a spindle motor for rotating the magnetic disk (2), and reading and writing information from the magnetic disk (2). Magnetic head 16 and a fixed shaft 12 for allowing the magnetic head 16 to access a desired track of the magnetic disk 2.
A magnetic disk device including a rotatable actuator 8 is provided with means for applying a driving force to the outer peripheral portion of the magnetic disk 2 when the spindle motor is started.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to a magnetic disk device, and more particularly to a magnetic disk device having auxiliary starting torque increasing means.

In recent years, there has been a demand for miniaturization and increase in capacity of magnetic disk devices, which are a type of external storage device for computers. The miniaturization has many mechanical advantages such as reduction of electric power and increase of resonance frequency.

On the other hand, in the design of a spindle motor for rotating a magnetic disk, the usable space becomes smaller and smaller due to downsizing, and it has become difficult to secure a sufficient starting torque.

[0004]

2. Description of the Related Art In a magnetic disk device for a computer, a CSS (Contact Start Stop) method is generally used in order to avoid damage due to contact of a magnetic head with a magnetic disk medium.

In the CSS system, the magnetic head balances the levitation force by the air fluid generated by the high speed rotation of the magnetic disk (for example, 3,600 rpm) and the force of the spring arm pressing the head against the disk.
Leaving with a minute gap (0.1 to 0.2 μm) maintained, data is read from and written to the magnetic disk.

When the rotation of the magnetic disk stops, the magnetic head contacts the magnetic disk by the spring force of the spring arm, and the head remains in contact with the magnetic disk while the rotation of the magnetic disk is stopped.

[0007]

From the standpoint of the design of the spindle motor that drives the magnetic disk, there is a trade-off relationship between the power consumption in the steady state and the starting torque, and if we try to reduce the power consumption in the steady state, The starting torque is also reduced.

In particular, in the case of a small-sized disc of 1.8 inches or less, it is strongly required to be driven by a battery because it is supposed to be portable. Therefore, there is no choice but to design in which the power consumption in the steady state is predominant, and in many cases the starting torque can be obtained only barely.

The spindle motor is an in-hub motor which is generally installed inside a magnetic disk, and particularly in the recent small-diameter disk such as a 1.8-inch disk, the inner diameter of the disk is relatively small (inner-outer diameter ratio 1: 4). ), It is very difficult to obtain a sufficient starting torque with a thin device having no margin in the height direction.

The load at the time of starting the magnetic disk device is roughly classified into a bearing friction load and a CSS system friction load between the head and the disk. In particular, when the head tends to be attracted to the disk, there is a problem that the latter becomes large and may fall into a state where it cannot start.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a magnetic disk device capable of ensuring a sufficient starting torque even when a small spindle motor is adopted. It is to be.

[0012]

In order to solve the above problems, the present invention provides a housing, a magnetic disk rotatably housed in the housing, and a spindle for rotating the magnetic disk. A magnetic disk device comprising a spindle assembly having a motor, a magnetic head for reading and writing information from and on the magnetic disk, and an actuator rotatable about a fixed axis for accessing the desired track of the magnetic disk, the spindle comprising: There is provided a magnetic disk device characterized in that means for applying a driving force to the outer peripheral portion of the magnetic disk when the motor is started is provided.

Examples of means for applying a driving force to the outer peripheral portion of the magnetic disk include the following means. (1) The torque of the head actuator is used in the outer diameter portion of the disk.

(2) Torque is applied to the disk by using a solenoid at the disk outer diameter portion. (3) Install a linear induction motor for start-up on the outer diameter of the disk.

[0015]

In view of the fact that the torque is represented by force × radius, the present invention increases the starting torque by driving the outer peripheral portion of the magnetic disk when the spindle motor is started. As a result, even when a small spindle motor with a small torque is adopted, it is possible to prevent the magnetic disk device from being unable to start.

[0016]

Embodiments of the present invention will now be described in detail with reference to the drawings. Referring to FIG. 1, there is shown a schematic plan view of the first embodiment of the present invention with a cover removed. The magnetic disk 2 is rotatably accommodated in the housing 4, and the magnetic field 2 is rotated in the direction of arrow A by the spindle motor assembly 6.

The spindle motor assembly 6 has a known structure, and has, for example, a fixed spindle shaft, a spindle hub rotating around the spindle shaft, and an in-hub spindle motor provided between the spindle shaft and the spindle hub. ing. The magnetic disk 2 is fixed to the spindle hub.

Reference numeral 8 is an actuator for allowing the magnetic head 16 to access a desired track on the magnetic disk 2.
The arm 10, which supports the magnetic disk 16 at its tip, swings around the fixed shaft 12 by the voice coil motor 11. The attachment portion 10a of the actuator 8 to the fixed shaft 12 has a substantially circular cross section.

The outer periphery of the magnetic disk 2 and the actuator 8
The circular cross-section mounting portions 10a face each other with a narrow gap. A wedge-shaped contact 18 made of resin, for example, is arranged in this gap.

The contactor 18 is urged by a spring 20 and pressed against a gap between the outer periphery of the magnetic disk 2 and the mounting portion 10a of the actuator 8, and is excited from the gap by exciting the solenoid 22. .

When the rotation of the magnetic disk 2 is stopped, the magnetic head 16 is moved to the inner side of the disk 2 and stands by while contacting the disk 2. When the spindle motor is activated, the magnetic disk 2 starts rotating in the direction of arrow A. Almost at the same time, a current for the actuator 8 to rotate in the direction of arrow B is applied to the boil coil motor 11 of the actuator 8.

As a result, the starting torque of the actuator 8 is transmitted to the outer periphery of the magnetic disk 2 via the wedge-shaped contactor 18, and assists the magnetic disk 2 in the direction of arrow A.

Generally, the torque of the actuator 8 is 2 to 3 times the starting torque of the spindle motor, and assuming that the inner / outer diameter ratio of the magnetic disk 2 is 1: 4, the starting torque of the spindle motor alone is 10 in simple calculation. More than twice the starting torque will be obtained at the outer peripheral portion of the magnetic disk.

Immediately after starting, the torque of the actuator 8 is transmitted to the magnetic disk 2 via the wedge-shaped contactor 18. Immediately after that, the solenoid 22 is excited to contact the contactor 18.
To pull out the contact with the disc 2
8 does not adversely affect the disk 2.

Even when the contactor 18 makes contact with the outer periphery of the disk 2 for a moment at the time of start-up, since it is a moment during an extremely low speed, the generation of dust or the like is slight and no problem occurs. Further, even when the magnetic head 16 and the magnetic disk 2 are attracted to each other, the actuator 8 can be slightly rotated due to the lateral rigidity of the head arm 10, and the starting torque of the actuator 8 is transmitted to the magnetic disk 2.

Referring to FIG. 2, there is shown an enlarged view of the contactor portion. In FIG. 2A, the wedge-shaped contactor 18 connects the outer circumference of the magnetic disk 2 and the mounting portion 10a of the actuator 8 by the spring 20. 2B shows a state in which the contact 18 is pulled out from the gap against the biasing force of the spring 20 by exciting the solenoid 22. FIG.

Referring to FIG. 3, there is shown a schematic plan view of the second embodiment of the present invention. In the description of the present embodiment, the constituents substantially the same as those in the first embodiment shown in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted.

This second embodiment is similar in principle to the above-mentioned first embodiment. However, in this second embodiment, not the starting torque of the actuator 8 but the attraction force of the solenoid 22 itself is used.

That is, while the magnetic disk 2 is not rotating, the wedge-shaped contactor 18 is pressed against the outer circumference of the magnetic disk 2 by the urging force of the spring 20. The solenoid 22 is excited almost at the same time when the spindle motor is started to start rotating the magnetic disk 2 in the direction of arrow A.

Then, the wedge-shaped contactor 18 is pulled in the direction of arrow C by the solenoid 22 against the urging force of the spring 20. At this time, the torque in the direction of arrow A is transmitted to the magnetic disk 2 by the frictional force generated between the contact 18 and the outer peripheral portion of the magnetic disk 2.

Referring now to FIG. 4, there is shown a schematic plan view of the third preferred embodiment of the present invention. FIG. 5 is a sectional view taken along line VV of FIG. The third embodiment has the same concept of driving the outer circumference of the magnetic disk 2 as the first and second embodiments described above, but is different in that a linear induction motor is used as a driving means.

That is, as shown in FIG. 4, three small electromagnets 32 each having a coil 30 wound around each yoke 28 are arranged on the outer peripheral portion of the magnetic disk 2 so that the yoke 2 sandwiches the disk 2, and the linear induction motor 26 is provided. Make up.

Rotating torque is generated by sequentially energizing the coil 30 with a predetermined phase difference. The linear induction motor 26 uses the magnetic field of the coil 30 to drive the magnetic disk 2
The eddy current is generated in the aluminum plate constituting the and the force generated between the eddy current and the magnetic field is used.

In this embodiment as well, as in the first and second embodiments described above, since the outer peripheral portion of the magnetic disk 2 is used, a starting torque can be obtained. The magnetic disk 2 can always be rotated by the linear induction motor 26, but it is used here only at the time of startup.

This is because when the linear induction motor 26 is driven, a large eddy current will flow through the magnetic disk 2, and this eddy current may be mixed into the minute signal read by the head 16 as noise. is there.

In the present embodiment, by using the linear induction motor 26 only at the time of starting, the temperature rise of the coil 30 can be ignored, and as a result, a very small electromagnet can be used.

[0037]

As described above in detail, according to the present invention, by driving the outer peripheral portion of the magnetic disk, the starting torque of the small disk can be greatly increased, and a small spindle motor with low power consumption is adopted. It has the effect of being able to.

Further, without adopting a complicated mechanism such as a magnetic head loading / unloading mechanism, it is possible to avoid the trouble of being unable to start, and it is possible to realize a highly reliable magnetic disk device.

[Brief description of drawings]

FIG. 1 is a schematic plan view of a first embodiment of the present invention.

FIG. 2 is an enlarged view of a contactor portion.

FIG. 3 is a schematic plan view of a second embodiment of the present invention.

FIG. 4 is a schematic plan view of a third embodiment of the present invention.

5 is a sectional view taken along line VV of FIG.

[Explanation of symbols]

 2 magnetic disk 6 spindle motor assembly 8 actuator 10 arm 10a circular section mounting portion 16 magnetic head 18 wedge-shaped contactor 22 solenoid 26 linear induction motor 28 yoke 30 coil 32 electromagnet

Claims (4)

[Claims] 1. A housing (4) and a magnetic disk for storing information rotatably accommodated in the housing (4).
(2), a spindle assembly (6) having a spindle motor for rotating the magnetic disk (2), a magnetic head (16) for reading and writing information from the magnetic disk (2), and the magnetic head (16) A magnetic disk device comprising an actuator (8) rotatable around a fixed shaft (12) for accessing a desired track of the magnetic disk (2), wherein the magnetic disk (2) is activated when the spindle motor is started.
A magnetic disk drive characterized in that a means for applying a driving force is provided on the outer peripheral portion of the magnetic disk drive. 2. The fixed shaft (1) of the actuator (8)
The mounting portion (10a) to the (2) has a substantially circular cross section, and the means for applying the driving force is the biasing means (20) when the power is off, the circular cross section mounting portion (10a) and the magnetic disk (2). ) Of the magnetic disk.
Wedge-shaped contactor (18) pressed against the outer periphery of (2),
Suction means (22) for separating the contact (18) from between the mounting portion (18a) and the outer peripheral portion of the magnetic disk (2) against the urging force of the urging means (20) when the spindle motor is started. 3. The magnetic disk drive according to claim 1, further comprising a drive force applied to the outer circumference of the magnetic disk by the torque of the actuator (8) when the spindle motor is started. 3. A contactor (18) for applying the driving force to the outer peripheral portion of the magnetic disk (2) by a biasing means (20) when the power is turned off, and the contactor when the spindle motor is started. A suction means (2) for separating the (18) from the outer peripheral portion of the magnetic disk (2) against the urging force of the urging means (20).
2. The driving force is applied to the outer circumference of the magnetic disk (2) by a frictional force between the magnetic disk (2) and the magnetic disk (2) when attracting the contact (18). The magnetic disk device described. 4. A magnetic disk as the means for applying the driving force.
(2) is composed of a plurality of electromagnets (32) installed so as to sandwich it, and the plurality of electromagnets (32) are sequentially energized to act as an induction motor only when the spindle motor is started,
The magnetic disk drive according to claim 1, wherein a driving force is applied to the outer peripheral portion of the magnetic disk (2).