JPH0330158A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To enable an acceleration feed forward operation with good accuracy by constituting the subject device in such a manner that the movement of a head disk assembly upon being acted by reaction force at the time of driving an oscillatory type head positioner is restricted to a rotative direction relative to a bearing means, and an output of an acceleration sensor is given to a head positioning servo means. CONSTITUTION:The device is composed of a buffer means 43 for attenuating rotary motion of the head disk assembly 31, which is provided between the head disk assembly 31 and a case 38, and the acceleration sensor 45 for detecting an acceleration component in the rotative direction relative to the bearing means of the head disk assembly 31, which is provided on the head disk assembly 31. The device is constituted in such a manner that the movement of the head disk assembly 31 upon being acted by reaction force at the time of driving the oscillatory type head positioner is restricted to the rotative direction relative to the bearing means, and the output of the acceleration sensor is given to the head positioning servo means 5. By this method, the acceleration feed forward operation with good accuracy is performed without attending upon a phase shift, etc.

Description

[Detailed Description of the Invention] [Summary] Regarding a magnetic disk device having a configuration including a head disk assembly equipped with a swinging type head positioner, the present invention enables highly accurate acceleration feedforward in a magnetic disk device having a swinging type head positioner. A seven-piece head disk assembly having a swing-type head positioner and a head positioning servo means, a casing for accommodating the head disk assembly, and a case in which the head disk assembly is mounted on the casing with respect to the head disk. 7
bearing means that passes through the center of gravity of the assembly and is rotatably supported around an axis that is parallel to the central axis of swing of the swing type head positioner; m* means for attenuating the rotational motion of the assembly; and an acceleration sensor provided in the head disk assembly for detecting an acceleration component in the rotational direction of the bearing means of the head disk assembly; The movement of the head disk assembly when a reaction force is applied to the drive of the position sensor is limited to movement in the rotational direction with respect to the bearing means, and the output of the acceleration sensor is applied to the head positioning servo means. It's structured like this.

[Industrial application field]

The present invention relates to a magnetic disk device having a seven-piece head disk assembly equipped with a swing type head positioner.

In magnetic disk drives, the seek operation in which the magnetic head is moved from one track to another on the magnetic disk involves transmitting track signals read by the magnetic head to the head positioner in order to accurately position the magnetic head on the target track. This is done by giving feedback.

However, head positioning accuracy deteriorates due to the reaction of the head position controller's own first seek operation and unbalanced vibrations in the disk rotation system.

Therefore, it is desirable to be able to seek with a magnetic head with high precision and without delay despite these influences.

[Conventional technology]

FIG. 6 shows an example of a conventional magnetic disk device 1. As shown in FIG.

Reference numeral 2 denotes a head disk assembly (hereinafter referred to as OA), which is provided with a magnetic disk 3, a linear head positioner 4 that moves linearly in eight directions indicated by arrows, and the like.

5 is the housing, and the mouth DA2 is on this mountain part! ! ! It is supported and accommodated by a shock member 6.

The magnetic disk device 1 is assembled into equipment with the housing 5 fixed.

7 is an acceleration sensor, which is fixed to the mouth DA2, and detects the acceleration of the mouth DA2 in the eight directions indicated by the arrows, which occurs with the operation of the head positioner 4.

8 is a head positioning servo circuit.

9 is the first addition point, and 10f and tl2 are added.

13 is an integrator for converting acceleration into displacement, and integrates twice.

14 is an amplifier.

The track information signal read by the magnetic head 11 is fed back to the first summing point 9.

Further, the output of the acceleration sensor 7 is applied to a second summing point 1o via an integrator 13.

When a target track signal is received at the terminal 12, the head positioner 4 is driven and the magnetic head 11 is moved in the direction of the target track. A signal obtained by correcting the target track position using a signal from the acceleration sensor 7, that is, a signal predicting a head positioning error due to low-frequency vibrations generated in a seek operation is added to the hend position 3/4. Track information signals from the magnetic head 11 are fed back, and the magnetic head 11 is accurately positioned on the target track.

In this manner, the magnetic disk device 1 described above employs an acceleration noise forward method in which a head positioning error due to low m vibrations caused by a seek operation is predicted and corrected by the servo.

[Problem to be solved by the invention]

As mentioned above, when the head positioner is a linear type, the direction of the acceleration generated at the mouth DA is the same as the moving direction of the head positioner, so the above acceleration feedforward method uses a single acceleration sensor. This can be achieved by simply setting it up.

However, as shown in FIG. 7, in a magnetic disk drive 21 having a swing type head positioner 20, if the acceleration feedforward method shown in FIG. 6 is directly applied, the following problems arise. . In FIG. 7, the same reference numerals are given to the parts that substantially correspond to the constituent parts shown in FIG. 6.

By driving the swing type head positioner 10, the opening OA2A
vibrates in the X direction, the Y direction, and the direction of rotation around the center of gravity G. Since the rigid body motion of the entire 10A has three degrees of freedom, if we know the acceleration vectors at three locations that are not on the same straight line, we can find them.

Therefore, in the mouth DΔ2A, acceleration sensors are provided at three locations whose sensitivity directions are not on the same straight line.

The calculation circuit 25 calculates the output of each acceleration sensor 22, 23, 24.
The rotational direction component (angular acceleration of the entire 10A) calculated from the mounting position of each acceleration sensor is outputted, and this output is supplied to the summing point 1o.

As a result, the swing type head positioner 20 of the magnetic disk device 21 is driven by an acceleration feedforward method, and the magnetic head 11 is positioned on the target track.

However, this includes calculation errors in the calculation circuit 25 and variations in the characteristics of the acceleration sensor, which deteriorates the accuracy of acceleration feedforward and takes time to position the magnetic head 11 to the target track.

Furthermore, three acceleration sensors, which are generally expensive, are required, which increases the cost accordingly.

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic disk device equipped with a swing type head positioner that enables accurate acceleration feedforward.

[Means to solve the problem]

The present invention provides: a head disk assembly having a swing type head positioner and head positioning servo means; a casing housing the head disk assembly; and the head disk assembly. a bearing means rotatably supporting the iA casing around an axis passing through the center of gravity of the head disk assembly and parallel to the central axis of swing of the swing type head positioner; and the head disk assembly and the casing. and an acceleration sensor provided in the head disk assembly to detect an acceleration component in the rotational direction of the bearing means of the head disk assembly. The movement of the head disk assembly when a reaction force is applied during driving of the swing type head positioner is limited to movement in the rotational direction with respect to the bearing means, and the output of the acceleration sensor is transmitted to the head positioning servo. This is a configuration that can be added to the means.

[Effect]

The bearing means limits vibrations of the head disk assembly in the direction of rotation.

Since the vibration direction of the head disk assembly is limited to one direction, a single acceleration sensor is sufficient.

As a result, compared to a configuration in which three acceleration sensors are installed, the viscosity of the acceleration feedforward is improved and the cost is reduced.

(Embodiment) FIGS. 1 and 2 show a magnetic disk device 30 according to an embodiment of the present invention. FIGS. 3 and 4 schematically show FIGS. 1 and 2.

31 is a head disk assembly (mouth DA);
A plurality of magnetic disks 32, a swing type head positioner 33, etc. are assembled.

The swing type head positioner 33 includes a swing center shaft 34, an arm 35 pivotally supported by the swing center shaft, a magnetic head 36 at one end of the arm 35, a novoile coil motor 37 at the other end of the arm 35, etc. .

38 is a casing, inside of which l-ID A 3 1
is accommodated.

40,408 is an axis, as shown in FIG.
It is provided so as to protrude from the opening DA31 on both sides, passing through the center of gravity G of A31 and coinciding with a line 41 parallel to the swing center axis 34.

The HDA 31 connects the shafts 40 and 40a to the bearings 4 of the housing 38, respectively.
2.42a.

As a result, the opening DA31 is restrained from displacement in the X direction and the Y direction, and can be moved around the line 41, so that the opening DA31 can move around the housing 3.
It is housed within 8.

43 is! ! It is a vibration isolating rubber member as a means of impact, and the mouth DA
It is interposed between the outer periphery of the housing 31 and the inner periphery of the housing 38 .

Reference numeral 44 denotes an auxiliary vibration-proofing rubber member, which is attached to the outer peripheral surface of the housing 38.

The vibration isolating rubber member 43 has a small spring constant, and has a small spring constant.
The rotational motion of A31 regarding the bearings 42, 42a is damped.

The auxiliary anti-vibration rubber member 44 has a larger spring constant than the above-described anti-vibration rubber member 43, and when installed, the auxiliary anti-vibration rubber member 44
0 and absorbs vibrations applied to the magnetic disk device 30 from the outside, and also absorbs vibrations in the X and Y directions to the DA 31.

There is a 45-meter acceleration sensor, which is installed on the outer periphery of HDA31.

As shown in FIG. 3, the acceleration sensor 45 has a sensitivity direction indicated by an arrow 46 between the sensor installation position and the center of gravity
It is installed in a direction that does not coincide with the line connecting 0a>.

The distance 11t (radius) from the center of gravity G of the acceleration sensor 45 is
, If the sensitivity direction 46 is in the X direction, the radius makes an angle with the
It becomes θ0.

The conversion from the acceleration a to the angular acceleration α can be accomplished by multiplying the acceleration II a by a constant 1 r sin θ0, and specifically by providing the gain adjustment section 49.

50 is a head positioning servo circuit.

51 is a first addition point, and 52 is a second addition point.

The track information signal read by the magnetic head 11 is fed back to the first summing point 51.

The output of the acceleration sensor 45 passes through the gain adjustment section 49 and the integrator 13, and is converted into the angular acceleration of the mouth DA31 and added to the second addition point 52.

Next, the operation of the mouth DA31 having the above configuration will be explained.

When a target track signal is applied to the terminal 53, the voice coil motor 37 is driven, and the swing type head positioner 3
3 is operated, the arm 35 rotates around the shaft 34, and the magnetic head 36 moves in the direction of the target track.

Due to the reaction force due to the operation of the swing type head positioner 33 and the unbalanced vibration of the spindle, the HDA 31 receives a force in the X direction, a force in the Y direction, and a force in the rotation direction (moment).
act.

Here, the mouth DA31 is @40.40a and the bearings 42, 42a
Since it is supported by, it does not vibrate in the X direction or the Y direction, and the direction of vibration is limited to the rotation direction.

In other words, the low-frequency vibrations that occur in the mouth DA31 during seek operation are limited to those in the rotational direction (in the case of a positioner with a well-balanced mass around the center axis of rotation, the head positioning error also occurs in the rotational direction). It is limited to only those caused by directional vibration.Therefore, the signal predicting this positioning error is
It can be obtained from the angular acceleration of the mouth DA31, and the eye DA31
The angular acceleration of can be obtained by the acceleration sensor of
A single acceleration sensor is sufficient to be installed.

A signal output from the acceleration sensor 45 and passed through the gain adjustment section 49 is added to the second addition point 52, and the signal is added to the line 54.
A signal predicting the head positioning error is outputted to the voice coil motor 37.

As a result, the acceleration feedforward is performed with high precision, and the magnetic head 36 reaches very close to the target track.

Eventually, the magnetic head 36 is accurately positioned on the target track by the track information signal fed back from the magnetic head 36, and the seek operation is completed.

FIG. 5 shows a magnetic disk device 6 according to another embodiment of the present invention.
Indicates 0.

This magnetic disk device 60 has a rubber sleeve 61.6 on the il1140.40a of the device 30 of the above embodiment.
1a and is rotatably supported by bearing sleeves 62 and 62a. Other than this,
It is the same as ¥AN30 above, and corresponding parts are given the same reference numerals and their explanation will be omitted.

The rubber sleeve 61.61a serves as the auxiliary vibration isolating rubber member 44.

〔Effect of the invention〕

As explained above, according to the present invention, the bearing means is provided to limit the vibration direction of the head disk assembly to only the rotational direction, and accordingly, it is only necessary to detect acceleration in the rotational direction, and the acceleration sensor is the only one. Since the configuration is such that acceleration feedforward is performed based on the output of the single acceleration sensor and taking head positioning errors into consideration, acceleration feedforward is can be performed with high precision without causing any phase shift. Furthermore, since a single acceleration sensor is sufficient, it is advantageous in terms of cost.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional front view of a magnetic disk @ storage according to an embodiment of the present invention, Fig. 2 is a cross-sectional view taken along line 1 and 2 in Fig. 1, and Fig. 3 corresponds to Fig. 1. 4 is a schematic diagram corresponding to FIG. 2, FIG. 5 is a diagram showing a magnetic disk device according to another embodiment of the present invention, and FIG. 6 is a diagram showing an example of a conventional magnetic disk device. FIG. 7 is a diagram showing an example in which the method shown in FIG. 6 is directly applied to a magnetic disk device having a swing type head positioner. In the figure, 30.60 is a magnetic disk device, 31 is a head disk assembly (DA), and 32 is a magnetic disk device.
33 is a magnetic disk, 33 is a swing type head positioner, 34 is a swing center shaft, 35 is an arm, 36 is a magnetic head, 37 is a voice coil motor, 38 is a housing, 40.40a is a shaft, 41 is a wire, 42 42a is a bearing, 43 is a vibration isolating rubber member, 44 is an auxiliary vibration isolating rubber member, 45 is an acceleration sensor, 49 is a gain adjustment section, 50 is a head positioning servo circuit, 51 is a first addition point, 52 is a first addition point 2, and 53 indicates a target track signal input terminal.

Claims (1)

[Claims] A head disk assembly (31) having a swing type head positioner (33) and a head positioning servo means (50); a casing (38) housing the head disk assembly (31); The head disk assembly is rotatably supported with respect to the housing around an axis (41) passing through the center of gravity (G) of the head disk assembly and parallel to the swing center axis (34) of the swing type head positioner. Bearing means (42
, 42a, 62, 62a), the head disk assembly (31) and the housing (3
8) for attenuating the rotational motion of the head disk assembly; and a buffer means (43) for damping the rotational motion of the head disk assembly; an acceleration sensor (45) for detecting the acceleration; the movement of the head disk assembly when a reaction force is applied during driving of the swing type head positioner is limited to movement in the rotational direction with respect to the bearing means; A magnetic disk drive characterized in that the output of the sensor (45) is applied to the head positioning servo means (50).