JPS63276766A - Head positioning device - Google Patents

Abstract

PURPOSE:To prevent the worsening of a positioning accuracy due to the wear of a tooth by making the pitch of the tooth of a rack into the prescribed magnification or below of the pitch of the concentric circle of a recording medium. CONSTITUTION:The pitch of the tooth of a rack 18 is constituted to two times or below of a track pitch. Thus, when a head is positioned onto a track, the gearing position of the tooth form of the rack 18 and the tooth form of a pinion 13 comes to be the same position relation, which is equal in the right and left directions in any track, the accuracy of the tooth form is bad, and even at the time of the wear of the tooth, it is not necessary to position some places at the middle of the gearing of the tooth, and when the pitch accuracy is secured, the head positioning accuracy is not worsened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to head positioning of a disk device, and more particularly to a head positioning device constituted by a rack and pinion.

[Prior Art] Conventionally, in a head positioning device using a rack and pinion, there is no example in which the pitch of the rack teeth is less than twice the track pitch. However, as an example of a head positioning device using a rack and pinion, , Jitsukō 49-3
No. 4340, JP 60-136067, U.S. Patent 4
As described in Publication No. 428012 and shown in Figure 5,
A device for positioning a head 4 in a disk device using a step motor 1, a rack 2, and a pinion 3 has been known.

FIG. 5 is a perspective view of a conventional head positioning device,
FIG. 6 is a detailed view of the rack and pinion of a conventional head positioning device.

[Problems to be Solved by the Invention] However, in the conventional head positioning device, the pitch of the concentric recording portions (hereinafter referred to as tracks) is several hundred.
Because it is minute, less than tm, for highly accurate positioning,
A structure in which a hybrid step motor 1 with 100 or more divisions is used to position the head 4 on 10 or more tracks while one tooth of the rack 2 and pinion 3 is engaged (
The pitch of the rack teeth is more than 10 times the track pitch), and the factors that determine the positioning accuracy of the head 4 are:
The division accuracy of the step motor 1, the tooth profile precision of the rack 2, and the tooth profile precision of the pinion 3 are involved, and high precision was required for each.

Furthermore, due to the repeated operation of moving the head 4 by the rack 3 and pinion 2, the tooth profile of the rack 3 and pinion 2 is worn out at the oblique part of the tooth profile shown in FIG.
This is because even if the tooth profile is an involute tooth profile, the teeth of the rack 3 and pinion 2 will slip at areas other than the pitch circle 5.

With such worn teeth, in a head positioning device that positions the head on several tracks, for example 10 or more, while a single tooth is engaged, the position of the head may be lower than the initial position.
Another problem is that the stopping position of the head changes as the teeth wear down.

The present invention is intended to solve these conventional problems, and its purpose is to provide a head positioning device using a rack and pinion that does not deteriorate the tooth profile accuracy of the rack and pinion or the head positioning accuracy due to tooth profile wear. It is in a place where we provide.

[Means for Solving the Problems] In order to solve the above problems, a head positioning device for a disk device according to the present invention includes a head for concentrically recording or reproducing on a recording medium on a disk; a step motor for moving and positioning the head in the radial direction of the recording medium; a pinion provided on the output shaft of the step motor; a carriage on which the head is mounted; The rack has a pitch that is less than twice the pitch of concentric recording of the medium.

[Function] According to the above configuration of the present invention, when positioning the head on a track, the tooth profile of the rack and the meshing position of the tooth profile of the pinion have the same positional relationship on any track (for example, the pitch of the rack (If the pitch is twice the track pitch, it will be every other track.) Even if the tooth profile is not accurate or the teeth are worn, there is no need to position at multiple points in the middle of the tooth engagement, so the pitch accuracy will be improved. If this is ensured, there will be no deterioration in head positioning accuracy.

[Embodiment] FIG. 1 is a perspective view of a head positioning device for a disk device in an embodiment of the present invention, and FIG.

FIG. 3 is a detailed diagram illustrating the engagement of the rack and pinion in FIG. 1.

In this embodiment, the outer diameter of the flexible disk, which is generally called a 3.5-inch flexible disk, is 3.5 inches.
This will be explained by referring to devices around the inch.

In FIG. 1, a pinion 13 is integrated with an output shaft 12 of a step motor 11. As shown in FIG.

A lower head 16 and an upper carriage 17 are mounted on a carriage 15 which is configured to be movable in the axial direction with respect to the guide shaft 14 . In FIG. 1, the upward ridge 17 is partially omitted to make the figure easier to understand.

The carriage 15 is configured to be rotatable around the guide shaft 14, and is equipped with a rack brake (19) provided with a rack 18.
is fixed to the carriage 15, and the rack 18 and pinion 13 are fixed to the carriage 15.
is engaged with the stopper in the direction of rotation of the carriage 15.

Further, the lower part of the rack plate 19 is bent into an L-shape, and the rack plate 19 is absorbed by an adsorption magnet 21 provided on the frame 20, thereby applying appropriate pressurization to the rack 18 and pinion 13. In this embodiment, the rack plate 19 was made of a magnetic material, so the above structure was possible. However, if the rack plate 19 is made of a non-magnetic material, another magnetic material may be attached to the carriage 15. Alternatively, it is also possible to attach the attraction magnet 21 to the carriage 15 and fix the magnetic material to the frame 20.

In this example, the pitch between tracks is 187.5μ.
m, and the pitch of the teeth of the rack 18 is 2 of the track pitch.
The diameter of the output shaft 12 is 1.5 mm, and the number of teeth of the pinion 13 is 10.

In the case of the above configuration, the rack 18 and pinion 13
The engagement is as shown in Figures 2 and 3.

In Fig. 2, when the pinion 13 and the rack 18 are engaged as shown in the figure, when the rack 18 is moved by 1/72 minutes, the rack 18 will move 1/2 the pitch of the teeth at the arrow 1 in the figure.
It moves in the direction of 0, as shown in Figure 3. Figure 3 is the second
Rack 18 is 1/
This is a diagram that has been moved two pitches. As can be seen from these figures, by making the tooth pitch of the rack 18 twice the track pitch, the contact area between the rack 18 and the pinion 13 is
Even if the teeth of the rack 18 or the pinion 13 are worn out as shown in FIG. 6, the teeth of the pinion 13 will mesh with the rack 18 evenly when the pinion 13 is stopped.
The relative positional relationship is always maintained in the same phase, and even if the engagement depth increases, the deterioration of positioning accuracy in the direction of movement of the carriage 15 can be suppressed to a minimum.

In addition, although FIGS. 2 and 3 show cases in which the teeth of the rack 18 and pinion 13 are ideally adjusted so that they are even on the left and right sides, it is possible that these teeth are not completely evenly engaged on the left and right sides. However, the above-mentioned effects can be obtained.

FIG. 4 is a diagram illustrating the engagement of the rack and pinion of the head positioning device of the flexible disk drive device in another embodiment of the present invention.

This embodiment also uses a head positioning device.

The structure is the same as that shown in FIG.

In FIG. 4, the rack 18 and pinion 13 are engaged, and the contact points are three points A, B, and C. The pitch P1 of the teeth of the rack 18 is the same as the track pitch.

In such a configuration, even if the rack 18 is moved by one track in the direction of arrow 20 in FIG.
When positioning the rack 18 on each track, as long as the pitch accuracy of the points A, B, and C is sufficient, the accuracy of the tooth profile along the way has no effect on the positioning accuracy.

Similarly, by setting the tooth pitch P1 of the rack 18 in FIG. 4 to 1/n of the track pitch (n is an integer), n
The contact portions between the teeth of every other rack 18 and the teeth of the pinion 13 have the same relationship as in this embodiment, and the same effect can be obtained.

Although the flexible disk drive device has been described above based on a specific embodiment, the present invention can be similarly implemented in hard magnetic disk devices, optical disk devices, etc., and has a wide range of applications.

[Effects of the Invention] As explained above, the present invention positions the head at several locations between the pinion and one tooth of the rack by configuring the pitch of the teeth of the rack to be twice the track pitch or less. As long as sufficient pitch accuracy of the rack and pinion teeth can be obtained, it is possible to provide a head positioning device that can eliminate the influence of tooth profile accuracy and prevent deterioration of positioning accuracy due to tooth wear.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a head positioning device of a flexible disk drive device according to the present invention. FIGS. 2, 3, and 4 are detailed views illustrating the engagement of the rack and pinion of the head positioning device of the present invention. FIG. 5 is a perspective view of a conventional head positioning device. FIG. 6 is a detailed view of the rack and pinion of a conventional head positioning device. 11・・・・・・・・・・・・・・・Step motor 13・・・・・・・・・・・・Pinion 15
・・・・・・・・・・・・・・・ Carriage 16...
・・・・・・・・・・・・Lower head 18・・・・・・
・・・・・・・・・Applicant Rudge and above Seiko Epson Co., Ltd. Agent 5? Physician Tsutomu Mogami and 1 other person Figure 1 Q School Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] 1) A head for performing concentric recording or reproduction on a disk-shaped recording medium, a step motor for moving and positioning the head in the radial direction of the recording medium, and the step motor A head positioning device comprising a pinion provided on the output shaft of the head, a carriage on which the head is mounted, and a rack provided on the carriage and having a tooth pitch that is less than twice the pitch of concentric recording of the recording medium. . 2) The head positioning device according to claim 1, wherein the pitch of the teeth of the rack is twice the pitch of concentric recording. 3) The head positioning device according to claim 1, wherein the pitch of the teeth of the rack is the same as the pitch of concentric recording. 4) The head positioning device according to claim 1, wherein the pitch of the teeth of the rack is set to an integer fraction of the pitch of concentric recording.