JPS5996571A - Disk head drive mechanism - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a head drive mechanism for aligning a head for writing or reading information to a track on a disk surface.

[Prior art]

FIG. 1 shows an outline of a conventional head drive mechanism.

1 is a disk, 2 is a head for writing or reading information from tracks on the disk surface, 3 is a guide arm that supports the head 2, 4 is a carriage that supports the head 2,
5 is a voice coil motor for positioning the head 2 to a target track, and 6 is a base. Generally, the positioning accuracy for the target track needs to be less than a few microns.
For this reason, the following countermeasures have been taken: (1) The factors contributing to position 11L determination errors cannot be reduced by mechanical and thermal design not only of the disk head drive mechanism but also of the entire device.

(2) The ability to follow the target track is improved by improving the performance of the positioning +t+lJ control circuit.

However, specifications for positioning accuracy become stricter as the storage density of disks increases. In particular, in a head drive mechanism configured as shown in Figure 1, it is necessary to position the head and the entire drive mechanism five times closely, so if the weight is reduced in order to meet the positioning accuracy specifications, the mechanical strength will decrease. However, if the driving force of the voice coil motor is increased, vibration may increase. As a result, the measures mentioned in (1) and (2) above become complicated and sophisticated, and there is a limit to the positioning accuracy. This hinders improvement in storage density.

[Purpose of the invention]

An object of the present invention is to provide a head and a drive mechanism that enable high-density and miniaturization of disks by performing highly accurate positioning.

[Summary of the invention]

The present invention is characterized by a first real frame mechanism using a motor for roughly aligning the drive means for positioning the head on the disk surface within a predetermined distance from the target track; It is mounted and follows the target truck to a treetop density of 1
[Embodiment of the Invention] A first embodiment of the head drive mechanism of the present invention will be described below with reference to FIG. 2. . FIG. 2 is an enlarged cross-sectional view of the guide arm 3, which is the main part of this implementation row. A cylindrical sliding part 7 is provided at the tip of the guide arm 3, and a disc-shaped piezoelectric body 8, a movable body 9, and a disc-shaped piezoelectric body 1 are mounted on this sliding part 7.
They are fitted together in the order of o. Reference numeral 11 denotes a support member that positions the movable body 9 at the reference position A. 12 is head 2 at the tip
It is a gimbal having a gimbal and is fixed to the movable body 9.

Next, the operation of the first embodiment of the head drive mechanism of the present invention described above will be explained. FIG. 3 is a sequence chart showing the operation when accurately positioning the head 2 to the target track. This sequence drives the voice coil motor 5 to roughly move the head 2 within a predetermined distance from the target track. The alignment sequence and the post-pressure r6 body 8
．． By applying a necessary voltage to lO, the movable body 9 between the piezoelectric bodies 8 and 10 is slid from a reference position of 1 tA along the sliding portion 7 of the guide arm, and the head 2 is aligned 41 by following the target track. It consists of a sequence of

The range of this rough alignment is determined by the maximum movement distance of the movable body 9 by the piezoelectric body 8.10.

Next, the precise positioning operation by the piezoelectric bodies 8 and 10 will be explained in detail. First, it is determined whether the head 2 is on the right or left side with respect to the target track. As this method, for example, IE E E'l'ransacti
on Qn MagrLetics (VoL-
MAGl 4, A4, Jlly 1978
5ervo as disclosed on page 176)
I) isk positionEncoding
Methods such as those described above can be applied. If the target trunk is sealed and the head is on the right, 111 on the right in Figure 2! A voltage JJl+ is applied to the piezoelectric body 10 of I to expand it in the vertical direction or thickness direction and move the dJ moving body 9 to the left with respect to the reference position A. If the head is on the left with respect to the target trunk, apply '-pressure/JO to the piezoelectric body 8 on the left side in Fig. 2 to expand it vertically and move the movable body 9 to the reference position +itA. Figure 4 shows this control principle.For example, the applied voltage is supplied according to the method described above. With a proportional system like 1 wholesaler,
By expanding the piezoelectric body 8 or 10 by the required amount, the movable body 9 can be moved and the head 2 can be precisely aligned with the target track.
i indicates the rightward displacement of the movable body 9 with respect to the reference position A due to the expansion of the piezoelectric body 8, XL indicates the leftward displacement of the movable body 90 with respect to the reference position A due to the expansion of the piezoelectric body 10, and y indicates the applied voltage.

Note that the maximum moving distance, the 1liJ elevation accuracy of proportional control, and the responsiveness are determined by the thickness of the piezoelectric body 8, IO, and the applied voltage.

In addition, in order to increase the rigidity at the stop position and maintain positional accuracy, a bias voltage is applied to the piezoelectric body 8.9 in advance, and vertical pressure can be applied by the support member 11 in this embodiment. , the motor used for the first drive means is
It only needs to be the same as the conventional one, and the specifications can be reduced. It's a size.
The piezoelectric body used for the second driving means is piezoelectric body 8. lO-\
By simply adjusting the applied voltage, extremely small displacements can be easily obtained, making it possible to achieve highly accurate alignment. The second embodiment of the head drive mechanism of the present invention will be explained with reference to FIG. 5. FIG. 5 also shows the mounting part of this embodiment. FIG. 3 is an enlarged cross-sectional view of a certain guide arm portion. In this embodiment, a disc-shaped piezoelectric body 8 and a movable body 9 are fitted into the cylindrical sliding portion 7 of the guide arm 3. The movable body 9 is positioned at a reference position A by means of a support member 11. The rest of the structure is the same as that shown in FIG. 2. The operation of this embodiment is shown in the same sequence chart as shown in Fig. 3, but the sequence for precise positioning involves applying a certain voltage only to the piezoelectric body 8 to make it follow the target trunk. The method for this is to apply a bias voltage to the piezoelectric body 8 and move it slightly in the vertical direction.
It is fixed with a support member 11 in the stretched state and this is used as a reference position. When the head 2 is on the right side with respect to the target track, the initial bias Ichikawa is decreased, the piezoelectric body 8 is contracted, and the movable body 9 is moved in the direction of the loaf relative to the reference position A. In addition, when the head 2 is on the left with respect to the target track, the initial bias pressure is increased, the pressure rlf is increased, and the rest 8 is further expanded to move the movable body 8 to the right with respect to the reference position 1fA. let Fig. 6 shows the entire principle of this suppression, and by increasing or decreasing the pressure to the initial bias r, the pressure body 8 is expanded or contracted by the necessary amount 1s. J'!1fJJ1000 can be used to precisely align the head with the first entertainment track at f-6.

In FIG. 6, XR is 11'J due to the expansion of the piezoelectric body 8.
'Reference position A K of moving object 9 9. Right displacement to lj, x
/ , , is the leftward displacement of the movable body 90 with respect to the reference position A due to the contraction of the piezoelectric body 8, y is the mark /JOi [pressure, and Vr is the initial bias-royal position.

In this embodiment, in addition to the effects of the first embodiment shown in Figs. 4 and 2, the structure and tUIJ 1. NI can be simplified.

Each of the above) @ In the example, 14G1's kaku・nh '1
The motor in the '= stage may be of any type, 1-stroke, Mu-suke-dan, or Nan-to-be-no-ki, and the IW etc. may be of 1-gen type as well as 1., so the specifications are The diameter will be reduced by 11. Further, as the piezoelectric body in the second driving means, a plate-shaped piezoelectric body that is displaced in the vertical direction or the thickness direction depending on the applied voltage is suitable, and it may be of any type, single type, or laminated type. .

As shown in FIG. 1, a plurality of head drive mechanisms are often used as a set depending on the number of heads. In this case, it is preferable to use the head drive mechanism of the present invention for the dedicated disk on which the track reference position has been rewritten, and to use the conventional one for the other disks. Further, in the case where each disk has a reference track position, it is preferable to use the head driver (14') of the present invention for each disk.

〔Effect of the invention〕

According to the present invention, by performing highly accurate alignment,
The higher performance and smaller size of discs led to IIJ Noh.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a conventional head drive mechanism, FIG. 2 is a cross-sectional view 1 showing essential parts of a first embodiment of an uninvented head drive mechanism, and FIG. 3 is a diagram showing a first embodiment 0. FIG. 4 is a sequence chart showing the operation, FIG. 4 is a diagram explaining the operation of the first embodiment, and FIG. Figure 6 is a diagram explaining the operation of Figure 2. 1... Disc, 2... Head, 3... Guide arm, 4... Carriage, 5... Motor, 6... Base, 7... Sliding body, 8, 10... Piezoelectric body, 9...
- Movable body, 11... Supporting material, 12... Ginopal. Figure 1 Figure 3 Roy 4- Figure XL A χF

Claims (1)

[Claims] 1. Align the head with the track on the disk surface! A first one-stop groove that uses motor sound to roughly align the ll71 mechanism within a predetermined distance from the target track, and a piezoelectric body mounted thereon that follows the target track for precise positioning. 1. A disk head drive mechanism comprising: a second drive mechanism;