JPH01106378A - Magnetic head positioning mechanism - Google Patents

Abstract

PURPOSE:To automatically restore a head to a CSS zone when a disk rotation is stopped by gradually increasing (decreasing) a cavity formed with an annular ring shaped permanent magnet fixed in a hollow sleeve to operate together with an arm holder and another annular ring shaped permanent magnet fixed at a position to correspond to that of the former permanent magnet. CONSTITUTION:When a current supplied to a coil 3 is disconnected while the head is separated from a specific area brought into contact with the head to be stopped on the disk (CSS zone), the N and S poles of a ring magnet 21 are attracted in the directions of the S and N poles of a ring magnet 15, an arm group 4 is turned up to the position where the head comes on the CSS zone, and strong restoring force can be obtained. On the other hand, at a positioner, the cavity formed with the ring magnets 15 and 21 is gradually increased (decreased) within a using range 23 so that the force by a lead wire to connect the head and an electronic circuit and the external force by a wind generated by the disk rotation can be canceled, and the synthesis of the external force and the force by the magnets becomes the restoring force.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a magnetic head positioning mechanism, and in particular to a so-called swing arm type voice coil that positions a magnetic head on an arbitrary track of a magnetic disk by rotational movement. The present invention relates to a magnetic head positioning mechanism using a motor.

[Conventional technology]

In general, a magnetic disk drive has multiple magnetic disks stacked on one spindle, rotated steadily by a spindle motor, and positioned by a magnetic head provided corresponding to the storage surface of the magnetic disk. mechanism(
Usually, this is called a carriage or a positioner, but hereinafter, these are representatively called a positioner).The magnetic disk has a configuration in which it positions a carriage or a positioner on a designated track of a magnetic disk to write or read information.

The operation of such a positioner is usually driven by a stepping motor in a small magnetic disk device that uses a magnetic disk with a diameter of about 13an, but the positioning operation by the stepping motor is controlled by oven loop control (servo control using feedback of positioning errors). Since the stepping angle is approximately 0.9 degrees, it is impossible to increase the track density of the magnetic disk beyond a certain level.

Therefore, in order to realize a device with high storage density even in a small magnetic disk device, it is necessary to use a voice coil motor and perform servo control to perform a positioning operation.

On the other hand, in order to improve the storage density of recent magnetic disk devices, when the magnetic disk is not rotating, the magnetic head is brought into contact with the corresponding storage surface of the magnetic disk and stopped. The so-called contact start-stop method (C8S method) is adopted, in which information is written and read while maintaining a fixed distance between the disk and the storage surface of the magnetic disk by floating it using the airflow generated by its rotation. . In such a C8S type magnetic disk drive, a specific area (hereinafter referred to as C8S zone) for contacting and stopping the magnetic head on the magnetic disk is designated as an area for writing and reading information (hereinafter referred to as R/ The magnetic head is installed outside (inner or outer circumferential side) of the C8S zone (referred to as the W zone), and when the information writing or reading operation (hereinafter referred to as R/W operation) is completed, the magnetic head is returned to the C8S zone and then the magnetic disk is A method is used to stop the rotation of the .

To execute such a return operation of the magnetic head to the C8S zone (hereinafter simply referred to as return operation), a program that causes the above return operation to be performed at the end of each business processing program of a system using a magnetic disk device is required. Therefore, conventionally, the above-mentioned matters have been noted in the business processing program creation manual to encourage each business program creator to incorporate the return operation program. However, in reality, not all business processing program creators strictly adhere to the above precautions, and as a result, a business processing program may be executed that lacks the automatic return program for the magnetic head. Since the rotation of the magnetic disk is stopped while the magnetic head remains on the R/W zone, the magnetic disk comes into contact with the magnetic head in the R/W zone and stops, thereby preventing damage to the storage surface of the magnetic disk ( This may result in a so-called head crash. Further, the same phenomenon as described above occurs when the power supply to the magnetic disk device is stopped for some reason during the R/W operation. Furthermore, when transporting or moving a magnetic disk device, impact force may be applied to the magnetic disk device, and this impact force may cause the magnetic head to move while in contact with the magnetic disk, causing scratches and damage to the storage surface. Sometimes.

In order to prevent damage to the magnetic disk due to such causes, an automatic return mechanism is installed that automatically returns to the C8S zone if the magnetic disk stops rotating while the magnetic head is on the R/W zone. You need to be prepared. For positioners that use a voice coil motor, especially a so-called swing arm type voice coil motor that rotates and oscillates around a fixed rotating shaft, the automatic return mechanism described above is not suitable for large magnetic disk drives. Some methods use a spring spring to automatically return the device to its original position, but this method requires a considerable amount of space to mount the related parts, so it is not suitable for small magnetic disk drives. However, it is difficult to provide this means because the necessary space is not available.

On the other hand, the positioner receives external forces from the lead wires (generally FPC) connecting the magnetic head and the electronic circuit, and from the wind caused by the rotation of the magnetic disk. This external force is large and, depending on the direction, may cause the magnetic head to move in the opposite direction to the direction in which it returns to the C8S zone.

Further, if this external force differs depending on the cylinder, the speed at which the positioner moves to the positioning operation varies, which may cause a positioning error or increase the error.

Conventional examples for solving such problems (Japanese Patent Application 1986-
113503) will be explained. FIG. 3 is a plan view showing the main parts of a conventional mechanism. Referring to FIG. 3, arms 4a to 4d each having a magnetic head 5 mounted on the tip thereof (in order to be able to mount a magnetic head on a magnetic field corresponding to the storage surface of a magnetic disk 22 equipped with a magnetic disk device) are shown in FIG. As shown, the rear parts of the arms (of which a plurality of arms are usually provided) are stacked and mounted on the arm holder 11 at predetermined intervals to form the arm group 4, and rotate as one unit around the rotation axis 6. It can be performed. A single coil 3 is provided at the rear of the arm group 4 (on the opposite side of the rotation axis 6 from the magnetic head 5), and permanent magnets 7 are provided above and below the coil 3, and Yokes are provided surrounding the top and bottom, left and right sides, and a magnetic circuit is constituted by the permanent magnet 7 and the yokes. Therefore, the coil 3 is directed in the positive direction or
By passing an appropriate current in the opposite direction, the coil 3 performs a rotational movement in the direction of the arrow IN or OUT, and the magnetic head 5
is positioned on a predetermined track of the magnetic disk 22.

4(a) and (b) are enlarged sectional views showing details of the XX section in FIG. 3 and Y-Y in FIG. 4(a).
FIG.

As shown in FIG. 4, the arms 4a to 4d have holes provided in their rear portions that fit into the outer periphery of the hollow cylindrical portion 11a of the arm holder 11, and spacer rings 12a to 12c.
The arms are stacked at a predetermined interval and are integrated into an arm group 4. The arm holder 11 is usually made of a lightweight material such as aluminum, and a hollow sleeve 13 made of carbon steel or stainless steel is fitted inside its hollow cylindrical portion 11a.

The arm holder 11 and the sleeve 13 are joined together by a manufacturing method such as uniform die casting, and are completely integrated within the operating temperature range of a normal magnetic disk device.

Ball bearings 16 and 17 are mounted inside the sleeve 13 at its upper and lower ends. The outer side of the outer ring of the lower ball bearing 17 is in close contact with the inner surface of the sleeve 13, and the inner side of the inner ring is fixed to the outer side of the rotating shaft 6 by adhesive. On the other hand, the inner ring of the upper ball bearing 16 is fixed to the rotating shaft, but there is a very small play between the outer ring and the sleeve 13, and the lower surface of the outer ring is constantly pressed upward by the compression spring 19. is recieving. Such a configuration eliminates play between the ball bearings 16 and 170 poles and the inner and outer races.

An annular iron piece holder 20 is fixed near the center of the inner surface of the sleeve 13, and its upper surface serves as a pedestal for supporting the lower surface of the compression spring 19. Iron piece holder 2
A piece of soft iron (or a piece of ferromagnetic material or a permanent magnet, hereinafter referred to as a representative piece of iron) 14 having a thickness substantially equal to 0 is fixed.

A ring magnet (15) composed of a permanent magnet is provided inside the iron piece holder 20 at a position corresponding to the iron piece 14, and its inner surface is fixed to the rotating shaft 6. The S pole corresponds to the iron piece 14. Note that the lower end of the rotating shaft 6 is fixed to a yoke 8 attached to the substrate IO, and the upper end thereof is screwed and fixed to the holding plate 2 via a fixing ring 18. The operation of the magnetic head positioning mechanism configured as described above is as described above, in which the magnetic head 5 is positioned on a predetermined track of the magnetic disk 22 by passing an appropriate current through the coil 3.

This positioning operation causes the iron piece holder 20, and therefore the iron piece 14, to rotate relative to the ring magnet 15, so that the iron piece 14 is located away from the ON and S poles of the ring magnet 15. If the current supplied to the coil 3 is cut off for some reason in this state,
The iron piece 14 is attracted to the ON and S poles of the ring magnet 15 and rotates the arm group 4 to the closest position, that is, to the position where the magnetic head 5 is above the C3S zone of the magnetic disk 22. (When the iron piece 14 is closest to the N and S poles of the ring magnet 15, the magnetic head
The relative positions of the iron piece 14 and the ring magnet 15 are determined so that they are above the 8S zone. ) When there is no external force such as the above-mentioned FPC force or the wind force caused by the rotation of the magnetic disk, the rotational force of this iron piece stops the rotational movement of the magnetic disk no matter where the magnetic head is located on the magnetic disk. When this happens, the magnetic head can be automatically returned to the C3S zone.

[Problem that the invention seeks to solve]

Although this mechanism of automatically returning the magnetic head to the C8S zone using a ring magnet and a corresponding iron piece is an extremely effective mechanism, the iron piece is held by an iron piece holder and attached to the inner surface of the sleeve. This has the disadvantage that the structure is complicated and assembly is not easy, and there is also a problem that it is difficult to obtain a sufficient return force due to leakage magnetic flux due to the structure. Furthermore, there are external forces such as FPC and wind power, and if the resultant force of this external force and the return force differs from cylinder to cylinder, there is a drawback that positioning error increases in normal R/W operation.

Therefore, an object of the present invention is to provide a C8 with a simple structure and easy assembly work, correct the external force applied to the positioning mechanism, reduce the positioning error, and increase the return force.
An object of the present invention is to provide a head positioning mechanism capable of returning the head to the S zone.

[Means for solving problems]

The magnetic head positioning mechanism of the present invention includes a hollow arm holder on which at least one arm carrying a magnetic head that writes information to or reads information from a magnetic disk is mounted, and a hollow arm holder provided inside the arm holder. a hollow sleeve that operates integrally with the arm holder; a first ball bearing having an outer ring fixed inside one end of the sleeve; and one end attached to the inner ring of the first ball bearing. A fixed rotating shaft, a second ball bearing having an inner ring fixed to the other end of the rotating shaft, and one end face of the outer ring of the second ball bearing contact with the end face of the outer ring of the second ball bearing to connect the two ball bearings. a compression spring that presses outward;
a first permanent magnet having at least a pair of annular magnetic poles that supports the other end surface of the compression spring and is fixed inside the sleeve; and a first permanent magnet on the rotating shaft. An annular second permanent magnet fixed at a corresponding position and having a magnetic pole at a position corresponding to the magnetic pole of the first permanent magnet is configured to gradually increase (reduce) a gap formed by the second permanent magnet.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1(a) is a cross-sectional view showing details of the main part of an embodiment of the present invention, and is a cross-sectional view corresponding to the XX cross-section of FIG. 3. Figure 1(b) is Y in Figure 1(a)
-Y sectional view.

Although the planar appearance of this embodiment is the same as that of the conventional positioning device shown in FIG. 2, the parts constituting the automatic return mechanism installed inside the sleeve are different. That is,
As shown in FIGS. 1(a) and 1(b), the ring magnet 15 is attached to the rotating shaft 6, which is the same as the conventional example shown in FIG.
A second ring magnet 21 is fixed to the inner surface of the ring. This ring magnet 21 is provided with a magnetic pole at a position corresponding to the magnetic pole of the ring magnet 15, and furthermore, the gap formed between the ring magnet 15 and the ring magnet 21 is gradually increased (decreased) within the range of use. The structure of the parts other than those mentioned above is the same as that of the conventional example explained based on FIG. 4.

Therefore, in the case of this embodiment, as in the conventional example, if the current supplied to the coil 3 is cut off when the magnetic head is away from the C8S zone, the N of the ring magnet 21
The poles and S poles are the S and N poles of ring magnet) 15.
The arm group 4 is rotated to a position where the magnetic head is attracted to the pole and closest to each other, that is, a position where the magnetic head is on the C8S zone of the magnetic disk. At this time, a strong return force can be obtained because a strong magnetic material can be used as the ring magnet 21, and because the magnetic circuit through which the magnetic flux passes is continuous, leakage magnetic flux is small. At this time, the force is applied to the ring magnet 15 and the ring magnet so as to cancel the external force 50 generated by the force of the FPC attached to the magnetic head, the force of the wind caused by the magnetic disk, etc., as shown in FIG. The gap formed by 21 is gradually increased (decreased) in the usage range 23, and the generated force is 51, which is the external force 50 and the force 51 due to the magnet.
The combined 52 becomes the restoring force.

Furthermore, since the ring magnet 21 can be constructed from a single component, the structure is simple and its assembly work is also easy.

Note that the ring magnet 15 and the corresponding ring magnet 21 can be configured to have two or more pairs of N-3 poles, if necessary.

〔Effect of the invention〕

As explained in detail above, by using the magnetic head positioning mechanism of the present invention, if the rotation of the magnetic disk stops while the magnetic head is on the R/W zone of the magnetic disk, it will automatically move to the C8S zone. Let's bring it back, the so-called head club.

This has the effect that the operation can be performed reliably when preventing the shock, and the manufacturing cost can be reduced because the assembly can be performed easily. Therefore, it is possible to obtain a magnetic disk drive having a low manufacturing cost, a small variation in external force due to each cylinder, that is, a small positioning error, and a highly reliable automatic return mechanism.

[Brief explanation of the drawing]

Figures 1 (a) and (b) are a cross-sectional view and a Y-Y cross-sectional view showing one embodiment of the present invention, Figure 2 is a diagram showing the return force distribution in the cylinder, and Figure 3 is a diagram showing a conventional magnetic head. A plan view showing the configuration of the positioning mechanism, FIG. 4(a) is
-X sectional view, and FIG. 4(b) is a YY sectional view of FIG. 4(a). 6...Rotating shaft, 11...Arm holder, 13...Sleeve, 15...Ring magnet. Agent Patent Attorney Uchihara Oto 3ρ: Ff'C, -1Jil=j, generated 13 return force'
! tJZ times 2; Keisai Kawara 2: Rotation ψum axis 3 Nikoil 7: Higashikyu, no;;; r4: End-
Mu snoring /f” arm small rugta: mee ki,
, ): 222 );b'? , Desashiku $3
@

Claims (1)

[Claims] a hollow arm holder on which an arm carrying a magnetic head for writing or reading information on a magnetic disk is mounted; a hollow sleeve provided inside the arm holder and operating in unison with the arm holder; , a first ball bearing having an outer ring fixed inside one end of the sleeve, a rotating shaft having one end fixed to the inner ring of the first ball bearing, and the other rotating shaft. a second ball bearing having an inner ring fixed to its end; a compression spring that contacts and presses the outer ring of the second ball bearing outward at one end thereof; and the other end surface of the compression spring. a first magnet having at least one pair of annular magnetic poles that supports the rotary shaft and is fixed inside the sleeve; and a first permanent magnet that is fixed at a position corresponding to the first permanent magnet on the rotating shaft. 1. A magnetic head positioning mechanism characterized in that the gap formed by a second annular permanent magnet having a magnetic pole at a position corresponding to the magnetic pole of the first permanent magnet is gradually increased.