JPH02287986A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To miniaturize a magnetic disk device by attaching a magnet to a carriage and providing a coil for attracting or repelling the magnet at the time when a current is transmitted. CONSTITUTION:A magnet 14 fixed to a carriage 5 is attracted or repelled by coils 11a, 11b at the time when a current is transmitted. A magnetic head 1 loaded on the tip of an arm 2 moves to a magnetic head stop area of a magnetic disk 8. A rectifying circuit 19 allows a current to flow to the coils 11a, 11b. A switching circuit 20 connects a coil of a spindle motor 9 to a power source line, and the circuit 19, when the power source is turned on, and when the power source is turned off, respectively. By turning the carriage 5 by rectifying and applying a counter electromotive voltage generated by an inertia rotation of the motor 9 at the time when a power source supply to the coils 11a, 11b is disconnected, the head 1 can be moved to the magnetic head stop area. In such a way, the device having high reliability is obtained by a miniature and simple constitution.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides a method for moving a magnetic head to a magnetic head stop area when the operation is stopped in a magnetic disk device used as an external storage device for computers, word processors, etc. This invention relates to improvements in means for

(Prior Art) As shown in FIG. 3, a conventional magnetic disk device of this type includes a magnetic disk rotating section composed of a magnetic disk 8, a spindle motor 9, etc., a magnetic head 1, an arm 2,
A magnetic head positioning section composed of a carriage 5, a rotating shaft 7, bearings 6a, 6b, etc., a cover 18, and a base 17 that prevent dust from entering the interior and support internal components.
It is made up of a casing part made up of. A magnetic head positioning motor is connected to the carriage 5 of the magnetic head positioning unit, and by driving the magnetic head positioning motor, the magnetic head 1 is positioned at a target position on the magnetic disk 8, and writing and reading operations on the magnetic disk 8 are performed. will be held.

When starting or stopping a magnetic disk device, the magnetic head 1 comes into contact with the surface of the magnetic disk 8 and stops. However, in order to protect the information recorded on the magnetic disk, there is a dedicated area inside the information writing area. A magnetic head stop area is provided so that the magnetic disk and the magnetic head always come into contact in the magnetic head stop area when the magnetic disk drive is started or stopped.

This type of technology includes a technology that uses coil springs, magnetic springs, the weight of the carriage, etc. to position the magnetic head in the stop area when the power is turned off, and a technology that uses the magnetic head drive motor to
A technique is used to position the magnetic head in a magnetic head stopping area by applying a back electromotive force generated when the spindle motor is stopped.

(Problem to be Solved by the Invention) However, in the technology that uses coil springs, magnetic springs, or the dead weight of the carriage, a load is always generated to position the magnetic head in the stop area even when the magnetic disk device is operating. Especially in miniaturized magnetic disk drives, there are problems such as an increase in the power consumption required by the magnetic head positioning motor and heat generation in the magnetic disk drive due to the increase in power consumption. Furthermore, in the method using a coil spring, fine particles of dust generated from the spring connecting portion adhere between the magnetic disk and the magnetic head, causing information destruction. Furthermore, coil springs have a limited lifespan even after repeated use, and are inferior to the reliability of magnetic disk drives. In the method using the carriage's own weight,
This results in a problem in that freedom in selecting the installation direction of the device is lost, and the use of the downsized device is restricted.

In addition, in the technology of applying the back electromotive voltage generated when the spindle motor is powered off to the magnetic head drive motor, it is necessary to add a complicated additional circuit to the motor drive circuit, so the circuit has to be miniaturized. However, if there is a limitation on the mounting area, the disadvantage is that the circuit cannot be constructed.

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic disk drive having a function of automatically positioning a magnetic head to a stop area, which solves the drawbacks of the prior art described above.

(Means for Solving the Problems) The present invention has the following means configuration to achieve the above object. That is, the magnetic disk device of the present invention includes an arm on which a magnetic head is mounted, a carriage for moving the arm in a substantially radial direction of the magnetic disk, and an automatic return am when the magnetic disk is not in operation. In an apparatus: A magnet fixed to a carriage; When a current is passed through the magnet, the magnet is attracted or repelled so as to move a magnetic head mounted at the tip of an arm attached to the carriage to a magnetic head stop area of a magnetic disk. A fixed coil; A rectifier circuit for flowing a rectified current to the fixed coil; A switching circuit that connects the coil of the spindle motor to a power line when the power is on and to the rectifier circuit when the power is off; This is a magnetic disk device characterized by the following.

(Example) Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a longitudinal sectional view and a partial block diagram of an embodiment of the present invention.

The magnetic head °1 is fixed to the tip of the arm 2, and the magnetic head °1 is fixed to the tip of the arm 2.
It is fixed to the carriage 5 by a clamp plate 4 via. The carriage 5 rotates around the rotating shaft 7 by bearings 6a and 6b, and the zero rotation for positioning the magnetic head 1 at a desired position on the magnetic disk 8 is as follows:
This is realized by the force generated by a rotary motor, and the rotary motor directly or through a speed reduction mechanism drives the carriage 5.
is connected to.

The magnetic disk 8 is connected to a spindle motor 9 by a clamper 1.
It is fixed by 0 and rotates. When the power is turned off to stop the operation of the device, the power supply to the spindle motor 9 is cut off.
The spindle motor continues its rotational motion due to its inertial motion, and as the coil passes through the internal magnetic circuit, an electromotive force (this is called a back electromotive force or back electromotive force) is generated in the coil of the spindle motor. The coil housed in the carriage 5 is wound in two parts, a coil lla and a coil llb, and is fixed to a rotating shaft 7.
The direction of the magnetic field formed by b is perpendicular to the axial direction of the rotating shaft 7, as shown by the dotted line. The coil lead wires 13a and 13b are connected to the groove 1 provided on the rotating shaft 7.
2 and is pulled out to the outside of the magnetic disk device.

The rotating shaft 7 itself does not rotate, the magnet 14 has a cylindrical shape and is fixed inside the carriage 5, and in this embodiment,
A yoke 15, which is a magnetic material, is provided inside the carriage 5, and the magnet 14 is fixed inside the yoke 15. The magnetic poles are exactly axially symmetrical with respect to the rotation axis 7.
inside the spot. The yoke 15 increases the efficiency of the magnet 14, prevents leakage of magnetic flux to the outside, and is useful for downsizing the magnet and protecting recorded information.

The spacers 16a and 16b are used to support the bearings 6a and 6b in position, and the base 17 supports the internal structure, and together with the cover 18, prevents dust from entering from the outside and protects the device. It has the function of constantly filling the interior with clean air.

As described above, even if the power supply to the spindle motor 9 is turned off during the operating state, the rotation does not suddenly stop due to the inertia of the magnetic disk 8, so a back electromotive force is generated in the drive coil of the spindle motor.

Therefore, a magnetic head stopping area is provided in advance inside or outside the information recording area on the magnetic disk 8, and the back electromotive voltage of the spindle motor is rectified by the rectifier circuit 19 to be connected to the coils 1)a and 11b. When applied, the coil l
The magnetic force formed by la and llb and the magnetic pole of the magnet 14 attract each other, causing the carriage 5 to rotate. This rotation is used to move the magnetic head 1 to the magnetic head stopping area of the magnetic disk 8.

A simple switching circuit 2 using a relay or transistor connects the coil of the spindle motor 9 to the power line when the power is on, and connects it to the rectifier circuit 19 when the power is off.
It is done by 0.

Note that the electromotive force generated by the spindle motor is a pseudo alternating current whose amplitude converges, so the coils 11a and 11
When applying voltage b, as shown in FIG. 2, the automatic return mechanism is rectified and operates only in one direction.

In this embodiment, the coil is wound in two parts and is fixed to the rotating shaft 7, and the magnet is cylindrical and fixed in the carriage 5, but the shapes and fixing positions of each are different from those in this embodiment. The carriage may be rotated by attracting (or repelling) a magnet attached to the carriage when a current due to a back electromotive force flows through the coil from the spindle motor. As long as the shape and arrangement are possible, it is sufficient.

(Effects of the Invention) As explained above, the magnetic disk device of the present invention has a magnet attached to the carriage, and a coil that attracts or repels the magnet when current is passed through it. The structure is such that the carriage is rotated and the magnetic head is moved to the magnetic head stopping area by rectifying and applying the back electromotive force generated by the inertial rotation of the spindle motor. This has the advantage of being a highly reliable device that does not have the drawbacks seen in .

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of a magnetic disk device of the present invention, FIG. 2 is a rectification diagram of an electromotive force of a spindle motor, and FIG. 3 is a longitudinal sectional view of a conventional magnetic disk device. 1...Magnetic head, 2...Arm,
3... Screw, 4... Clamp plate, 5... Carriage, 6a, 6b...
... Bearing, 7 ... Rotating shaft, 8 ...
・Magnetic disk, 9... spindle motor,
10... Clamper, lla, Ilb...
... Coil, 12 ... Groove, 13a, 13
b... Lead wire, 14... Magnet,
15...Yoke, 16.16a, 16b-...
----- Spacer, 17... Base, 18.
...Cover 19... Rectifier circuit, 20.
...Switching circuit. Agent Patent Attorney Yoshihiro Hachiman

Claims (1)

[Claims] In a magnetic disk drive equipped with an arm on which a magnetic head is mounted, a carriage for moving the arm in a substantially radial direction of a magnetic disk, and an automatic return mechanism when the magnetic disk is not in operation; a magnet fixed to the carriage; ; a fixed coil that attracts or repulses the magnet so as to move the magnetic head mounted on the tip of the arm attached to the carriage to a magnetic head stopping area of the magnetic disk when current is passed therethrough; A magnetic disk drive comprising: a rectifier circuit for flowing current; and a switching circuit that connects a coil of a spindle motor to a power line when the power is on and to the rectifier circuit when the power is off.