JPS63206972A - Head positioning device - Google Patents

Abstract

PURPOSE:To eliminate an effect of the accuracy of tooth profile and to prevent the accuracy of positioning from deteriorating due to wear of teeth by multiplying the number of steps of a step motor by 1/2 or an integer for the number of teeth of a pinion. CONSTITUTION:By multiplying the number of steps of the step motor 11 by 1/2 for the number of teeth of the pinion 13, a contact part between a rack 18 and the pinion 13 is equalized on right and left relatively to their respective teeth each other. Consequently, at the time of positioning a head to a track position, the meshing position of the rack 18 with the pinion 13 in their respective teeth profiles is in their same positional relations with regard to any tracks, so that even if the accuracy of tooth profile on the pinion 13 and rack 18 is not so good, and on the other hand even if their teeth are worn out, it is not necessary to reposition in various points in the idle of their intermesh. In this way, the accuracy of their gear pitch will never be deteriorated.

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 composed of a rack and a pinion, there has been no example in which the number of teeth of the nion provided on the output shaft of a step motor is 2/1 or more of the number of steps of the step motor. Examples of head positioning devices using pinions include Utility Model Publication No. 49-34340, Japanese Unexamined Patent Publication No. 60-136067, and U.S. Patent No. 442801.
As described in Publication No. 2 and shown in FIG. 5, a step motor 1, a rack 2, and a pinion 3 in a disk device are
A head 4 positioning device was known.

FIG. 5 is a perspective view of a conventional head positioning device,
￥S6 Figure is a detailed diagram of the rack and pinion of a conventional head positioning device.

[Problems to be Solved by the Invention] However, in conventional head positioning devices, the pitch of concentric circles (self-recorded portions (hereinafter referred to as tracks)) is as small as several hundreds of μm or less. A hybrid step motor 1 with 100 divisions or more in one rotation of the motor is used, and the tooth 1 of the rack 2 pinion 3
The head 4 is positioned on five or more tracks while the sheets are engaged (the number of teeth on the pinion is less than one-fifth of the number of steps on the step motor), and the factors that determine the positioning accuracy of the head 4 are: The division accuracy of the step motor 1, the tooth profile accuracy of the rack 2, and the tooth profile precision of the nion 3 are related to each other, and high precision was required for each.

Furthermore, due to the repeated movement of the head 4 by the rack 3 and pinion 2, the tooth profiles of the rack 3 and pinion 2 are worn away at the shaded portions of the tooth profiles in FIG.
The reason for this is that even if the tooth profile is an involute tooth profile, slippage occurs at the contact area between the tooth profile of the rack 3 and the pinion 2 in the meshing area other than the pitch circle 5, which cannot be avoided. With such a worn tooth, in a head positioning device that positions the head on five or more tracks during meshing of one tooth, as the rack or pinion teeth wear progresses with respect to the initial positioning, There is also a problem that the positioning position changes.

Therefore, the present invention is intended to solve these conventional problems.The purpose of the present invention is to eliminate the influence of the tooth profile accuracy of the rack and pinion, and to prevent deterioration of head positioning accuracy due to wear of each tooth. The present invention provides a head positioning device using a rack and pinion instead of a rack and pinion.

[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 concentric recording or reproducing on a disc-shaped recording medium. , a step motor for moving and positioning the head in the radial direction of the recording medium every one step or every multiple steps, and two steps of the step motor provided on the output shaft of the step motor. It is characterized by comprising a pinion having teeth of 1/2 or more, a carriage on which the head is mounted, and a rack provided on the carriage and meshing with the pinion.

[Function] According to the above configuration of the present invention, when the head is positioned at a track position, the meshing position between the tooth profile of the rack and the tooth profile of the pinion is the same on every track (for example, when one track is When the step motor moves in one step, and the number of teeth on the pinion is half the number of steps on the step motor, it moves every other track.) Even if the tooth profile accuracy of the pinion and rack is poor,
Even if the teeth are polished, there is no need to position the head at multiple locations in between the meshing teeth, so as long as the pitch accuracy is maintained, there is no deterioration in the head positioning accuracy.

Embodiment J FIG. 1 is a perspective view of a head positioning device for a disk drive 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 upper carriage 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 has a rack plate 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 to act as a stopper for 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, since the rack plate 19 was made of a magnetic material, 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 (module 0.11).
9) It is (2 of the number of steps of the step motor)
l) When configured as above, 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 step motor 11 is rotated for one step (in this embodiment, a 4-phase permanent step motor is used, When switching only one phase to the next excitation phase from a state where two phases are energized, the step motor rotates 18 degrees in one step.) The pinion 13 also rotates 18 degrees, and the pinion 13 and rack 18
The meshing is as shown in Figure 3. As can be seen from these figures, by setting the number of teeth of the pinion 13 to half the number of steps of the step motor 11, the contact area between the rack 18 and the pinion 13 becomes equal on the left and right sides of each tooth. Even if the teeth of the rack 18 or pinion 13 are worn out as shown in FIG. 6, the deterioration in positioning accuracy can be minimized.

Note that although Figures 2 and 3 show the case where the WR adjustment is ideally made so that the teeth of the rack 18 and pinion 13 are evenly meshed on the left and right sides, Even without it, the above-mentioned effect can be obtained.

Furthermore, a small gear with a module of 0.119,
By combining a step motor with a small number of steps (20 steps), the outer diameter of the pinion tooth can be reduced to 1.5 mm, and the pinion can be configured directly on the shaft of the step motor.
In addition to improving the precision of the pinion, the motor shaft diameter is small, reducing friction loss on the motor shaft, making it possible to replace the motor bearing with an inexpensive metal bearing instead of an expensive ball bearing. .

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.

In this embodiment as well, the head positioning device has the same structure as that shown in FIG.

In FIG. 4, the rack 18 and the pinion 13 are engaged, and there are three contact points A, B, and C.

The number of teeth of the pinion 13 is the same as the number of steps of the step motor 11.

In such a configuration, when the step motor 11 is rotated step by step, the pinion 13 also moves by one tooth, so the contact area between the rack 18 and the pinion 13 is almost the same as the three teeth A, B, and C before the movement. 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 increasing the number of teeth of the pinion 13 in Fig. 4 by n times the number of steps of the step motor 11 (n is an integer).
, and the teeth of the pinion 13 mesh every n teeth with the teeth of the rack 18 for positioning. Therefore, the contact between the teeth of the rack 18 and the teeth of the pinion 13 is the same as in this embodiment, and the same effect can be obtained. Obtainable.

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 has the advantage of increasing the number of teeth of the pinion to half or an integral multiple of the number of steps of the step motor. It is no longer necessary to position the head at the same time, and as long as the pitch accuracy of the rack and pinion teeth is sufficient, the influence of the accuracy of the tooth profile can be eliminated, and the head positioning device of the disk device can be created that can prevent the deterioration of positioning accuracy due to tooth wear. It has the effect of being able to provide

[Brief explanation of the drawing]

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・・・・・・
・・・・・・・・・・・・Lack and above Applicant Seiko Epson Co., Ltd. Representative Patent Attorney Tsutomu Mogami and 1 other person

Claims (1)

[Claims] 1) A head for performing concentric recording or reproduction on a disk-shaped recording medium, and a head for moving and positioning the head in the radial direction of the recording medium every one step or every several steps. A step motor and 2 steps of the step motor installed on the output shaft of the step motor to perform
A head positioning device comprising a pinion having teeth of 1/2 or more, a carriage on which the head is mounted, and a rack provided on the carriage and meshing with the pinion. 2) In the disk device, the head according to claim 1, wherein the pitch of the teeth of the rack provided on the carriage is twice or less the pitch of concentric recording of the recording medium. Positioning device.