JPH0482061A - Swing arm driving device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of backlash due to gears by shifting teeth of first and second gears from each other in the initial position and providing a tension generating spring which turns and returns the second gear. CONSTITUTION:At the time of positioning (initial state), teeth 5c... of a transmission gear 5 and teeth 6e... of a tension gear 6 are shifted from each other by a half pitch. In this state, teeth 2a... of a swing arm 2 turn the tension gear 6 counterclockwise against a tension generating spring 7 and are fitted between teeth 5c and 5c of the transmission gear 5 and are engaged with them. The tension gear 6 is pressed to teeth 2a of the swing arm 2 by the tension generating spring 7. Thus, the occurrence of backlash is prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a swing arm drive device incorporated in a magnetic recording/reproducing device, etc., and particularly relates to a swing arm drive device that transmits the driving force of a drive motor to the swing arm via a gear. The present invention relates to a swing arm drive device.

[Conventional technology]

Conventionally, in magnetic recording and reproducing devices using hard-type magnetic disks, a magnetic head is mounted on the tip of the magnetic disk by swinging a rotatably supported swing arm. A method of transporting in the radial direction is adopted. In order to swing the swing arm, a steel belt whose middle portion is wound around a pulley rotated by a drive motor is stretched along the wall of the swing arm, and the pulley is driven to rotate. , winding and unwinding steel belts. In other words, this steel belt is
Both ends are screwed to the swing arm, and are constantly biased by a tensioner such as a leaf spring in order to reliably transmit the driving force, so when the pulley winds and unwinds the steel belt, , the swing arm swings about the rotation axis, making it possible to transport the magnetic head to a predetermined position.

In addition, as a rotating magnetic sheet recording and/or reproducing device using a flexible type magnetic disk,
-4262, and this device has a head attached via a plate spring to the tip of an L-shaped head moving arm whose midway part is rotatably supported by a pivot shaft mounted on the case board. A slider is attached. Further, the base end of the moving arm is abutted and engaged with a retaining shaft mounted on a ratchet that is rotatable around the ratchet shaft. The ratchet wheel is meshed with a pinion that is integrated with the ratchet wheel, and by rotating the ratchet wheel, the arm rotates around the ratchet shaft, moves the retaining shaft around the ratchet shaft, and moves the movable arm around the pivot shaft. It is designed so that it can be rotated.

The base end of this head moving arm is pressed against the engagement shaft by a tension spring to suppress backlash of the pinion.

[Problem to be solved by the invention]

However, in the former type of conventional swing arm drive device, the steel belt is fixed to the swing arm using screws, so there has been a problem that assembly is poor when the steel heald is stretched.

In addition, the strength of the part where the steel belt is screwed is slightly weaker, and stress is concentrated there, so
There was a risk that the steel belt would break after a long period of time. Furthermore, if the steel belt part is tightly attached to the wall surface of the steel belt and secured with screws, the extension side of the steel belt near the screwed portion will tend to separate from the wall surface of the swing arm when tension is applied. This causes variations in tension, which causes a deterioration in the feeding accuracy of the magnetic head.

On the other hand, the latter, like the former, is difficult to assemble and requires a space for installing a tension spring, which is an obstacle to miniaturization. Further, since the spring force due to the tension springs is applied to one direction of the head transport direction, the head position differs depending on the transport direction, resulting in deterioration of feeding accuracy.

The present invention has been made in view of the problems of the prior art described above, and aims to prevent the occurrence of backlash caused by gears, to simplify assembly, to achieve miniaturization, and to improve feed accuracy. An object of the present invention is to provide an improved swing arm drive device.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a drive motor;
In the swing arm drive device, the swing arm is connected to the drive motor via a transmission means and is swingably driven; a gear mechanism meshed with the teeth and attached to the drive shaft of the drive motor; the gear mechanism includes a first gear fixedly attached to the drive shaft; and a gear mechanism loosely fitted to the drive shaft. a second gear disposed between the first gear and the second gear, the initial position being a state in which the teeth of the first gear and the teeth of the second gear are shifted; This configuration includes a tension generating spring that causes the second gear to return to rotation.

[Effect]

By the means, the teeth of the second gear are rotated against the tension generating spring, and the teeth of the swing arm are meshed between the teeth of the first gear. Therefore, the teeth of the second gear and the teeth of the first gear engage with each other in a sandwiching manner, thereby preventing backlash from occurring.

〔Example〕

Hereinafter, embodiments of the present invention will be described based on the drawings.

Fig. 1 is a vertical sectional view of the main part of the swing arm drive device according to the present invention, Fig. 2 is a plan view of the main part of Fig. 1, Fig. 3 is an exploded perspective view of the gear mechanism, and Fig. 4 (a) is An explanatory diagram of the gear mechanism in a state where the gears of the swing arm are not engaged, Figure 4 (
b) is an explanatory view of the gear mechanism in a state where the teeth of the swing arm are in mesh with each other.

A magnetic recording/reproducing device, for example, a floppy disk drive device, includes a frame, a slide plate that is slidable on the upper surface of the frame, a holder that holds the disk cartridge, a carriage on which a magnetic head is mounted, and a carriage that supports the disk. a carriage transport mechanism for transporting the magnetic head in the radial direction of the magnetic disk, a turntable on which the disk is placed, a motor for rotationally driving the turntable, and a swing arm drive mechanism 1 for transporting the magnetic head in the radial direction of the magnetic disk. It mainly consists of

This swing arm drive mechanism 1 includes a swing arm 2 rotatably supported by a frame, and a toothed portion 2a carved along the wall surface of the swing arm 2 on the antimagnetic head mounting side.
, 2a......, a gear mechanism 3 that meshes with this tooth portion 2a, and a motor 4 to which this gear mechanism 3 is attached.
The motor 4 is driven to rotate the drive shaft 9a, and the swing arm 2 is connected to the swing arm 2 via the teeth 2a of the drive shaft 4a meshing with the gear mechanism 3.
I'm trying to rotate it.

The gear mechanism 3 is configured to eliminate pack runsh caused by such meshing of gears. That is, the gear mechanism 3 has a transmission gear 5 which is a first gear fixed to the drive shaft 4a, and is loosely fitted to the drive shaft 4a.
A molded tension gear 6, which is a second gear laminated on the transmission gear 5, and a storage recess 6a for the tension gear 6.
A coil portion 7a is housed therein, and both bent ends 7b are connected to a tension gear 6 and a transmission gear 5.
and a tension generating spring 7 that can come into contact with the abutment walls 6c, 6c, and 5a, 5a. 5b, 6d
is a hole through which the drive shaft 4a is inserted.

In addition, 8 is an E ring, 9 is a hair ring, and 10 is a case.

The operation of the embodiment configured in this way will be explained. In the non-meshing state, both ends 7b, 7b of the tension generating spring 7 abut against the contact walls 5a, 5a, 7c, 7c of the transmission gear 5 and the tension gear 6, respectively, as shown in FIG. 4(a). There is. Therefore, the tension gear 6 is positioned with respect to the transmission gear 5 defined on the drive shaft 4a. During this positioning (initial state), each tooth portion 5c of the transmission gear 5 and the tension gear 6...
e...... is in a state where the pitch is shifted by half.

From the state shown in FIG. 4(a), the toothed portion 2a of the swing arm 2 is moved to connect the tension gear 6 to the tension generating spring 7, as shown in FIG. 4(b). The tooth portions 5c, 5 of the transmission gear 5 are rotated counterclockwise against the
It is inserted between C and engaged.

The tension gear 6 is pressed against the teeth 2a of the swing arm 2 by a tension generating spring 7 to prevent backlash from occurring.

In the embodiment configured in this way, the tension generating spring 7 is built into the gear mechanism 3, and the structure is simple, making it possible to achieve miniaturization and space saving.

Further, since the transmission gear 5 has only a hole 5b having an irregular shape in the radial direction, it can be easily manufactured by a sheet metal cutting method.

Further, by making the transmission gear 5 made of metal, loosening of the fitting (press fit) to the drive shaft 4a, removal due to creep, etc. are less likely to occur.

Furthermore, as described above, backlash can be prevented from occurring, and the same effect can be achieved in either direction of rotation of the drive shaft 4a, which is advantageous in terms of the operation of the swing arm 2.

Further, the gear mechanism 3 can be assembled in a sequentially stacked manner, and although some jigs are required for assembling the tension generating spring 7, overall assemblability is improved.

Further, since the tension generating spring 7 is attached to the transmission gear 5 and the tension gear 6 in such a manner as to generate an initial pressure, the tension generating spring 7 will not come off inadvertently.

Incidentally, the present invention is not limited to the above-mentioned embodiments, but the present invention may use a coil spring as the tension generating spring, and have both ends of the coil spring in contact with the transmission gear and the tension gear.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to provide a swing arm drive device that prevents the occurrence of backlash caused by gears, is easy to assemble, can be downsized, and has good feed accuracy. .

[Brief explanation of the drawing]

Fig. 1 is a vertical sectional view of the main part of the swing arm drive device according to the present invention, Fig. 2 is a plan view of the main part of Fig. 1, Fig. 3 is an exploded perspective view of the gear mechanism, and Fig. 4 (a) is An explanatory diagram of the gear mechanism in a state where the teeth of the swing arm are not engaged, Figure 4 (
b) is an explanatory view of the gear mechanism in a state where the teeth of the swing arm are in mesh with each other. 1... Swing arm drive mechanism, 2...
・・・・・・Swing arm, 3・・・・・・・・・
Gear mechanism, 4...Moori, 5...
...Transmission gear, 6...Tension gear, 7...Tension generation spring. Figure 4 (a)

Claims (1)

[Claims] A swing arm drive device comprising a drive motor and a swing arm connected to the drive motor via a transmission means and driven to swing freely, the transmission means comprising:
It consists of a toothed part carved into the wall surface of the swing arm, and a gear mechanism that meshes with the toothed part and is attached to the drive shaft of the drive motor. a fixedly installed first gear, a second gear loosely fitted to the drive shaft, and a tooth portion of the first gear and a second gear disposed between the first gear and the second gear; and a tension generating spring that causes the second gear to return to its rotational position by setting the second gear to an initial position shifted from the teeth of the swing arm drive device.