JPH0325763A - Rotary actuator for recording and reproducing device - Google Patents

Abstract

PURPOSE:To easily perform assembly and to improve productivity by providing a first spring member to press an inner wheel in the axial direction of a fixed shaft, and a second spring member having an elastic modulus larger than that of the first spring member and to press an outer wheel in a direction opposite to the axial direction. CONSTITUTION:The outer wheel 15 is pressed downward with a wave washer 17 (second spring member) as a flat spring member to be interposed between a spring receiver 45 fixed at the upper end face part of a boss hole 41 with a tightening screw 43, and a pre-load is supplied to the wheel. Thereby, play in the axial direction can be prevented from occurring. Meanwhile, a compression coil spring (first spring member) 13 is interposed between the inner wheel 11 and a stopper part 37, and the inner wheel 11 is pressed upward in a direction opposite to the pressing direction of the washer 17. The elastic modulus of the spring 13 is set smaller than that of the washer 17. Since the elastic modulus of the washer 17 is set at a comparatively large value, it is easy to generate a large manufacturing error, but the manufacturing error can be absorbed by providing and deflecting the spring 13.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a low actuator for a recording and reproducing apparatus that includes a transducer that is movably positioned relative to a recording medium and records and reproduces information.

(Prior Art) In a Winchester type magnetic disk device, a magnetic head as a transducer is supported at the tip of an actuator arm and is moved and positioned to an arbitrary position on a magnetic disk as a storage medium. As the demand for high-capacity actuators capable of high-speed seeking is increasing, there is a need for actuators that are compact and suitable for devices capable of high-speed seeking.

An example of such a magnetic disk device is shown in FIGS. 4 and 5. In this system, a suspension 27 having a magnetic head 3 at its tip is supported by an actuator arm 5 that is rotated by a drive motor 23, and the rotation of the actuator arm 5 moves the magnetic head 3 to an arbitrary position on the surface of a magnetic disk. It has a configuration for positioning. The actuator arm 5 has a boss portion 21 on the base end side.
It is rotatably supported by two upper and lower ball bearings 9.19 interposed between the fixed shaft 7 and the fixed shaft 7.

The lower ball bearing 19 has an outer ring and an inner ring fixed to the actuator arm 5 and the fixed shaft 7, respectively. On the other hand, the inner ring 11 of the upper ball bearing 9 is fixed to the fixed shaft 7, but the outer ring 15 is rotatable with respect to the actuator arm 5.

The outer ring 15 is pressed upward in the axial direction by a compression coil spring 51 via an outer ring presser 55, thereby preventing backlash in the axial direction. Further, a coil spring 49 is provided between the outer ring 15 and the boss portion 21 to press the outer ring 15 toward the magnetic head 3 to prevent play in the radial direction. 57 is a housing in which the drive motor 23, actuator arm 5, magnetic disk 1, etc. are housed.

(Problem to be Solved by the Invention) In the low actuator of the recording/reproducing device as described above, a compression coil spring is provided on the outer ring of the bearing on the rotating actuator arm side to apply preload in the axial direction. When the actuator arm is rotated at high speed, rotational moment corresponding to its acceleration/deceleration is transmitted to the compression coil spring, and the compression coil spring generates transient vibration according to its torsional resonance frequency. This occurs and is transmitted to the actuator arm, causing the actuator arm to vibrate as well, which becomes an obstacle to increasing the seek speed.

The torsional resonance frequency of a compression coil spring is inversely proportional to the wire length of the coil, so reducing the number of turns of the coil increases it, causing excessive a
Although the vibration time is reduced, it is difficult to reduce the number of turns while satisfying the required manufacturing precision, and therefore it is difficult to achieve high-speed seek with such compression coil springs.

Also, after completing the seek, if you position with the positioning servo,
In the Jt actuator arm, transient vibrations corresponding to the torsional resonance frequency of the compression coil spring tend to occur, increasing servo errors and lowering the reliability of the device.

In order to avoid this, if a spring with a high resonance frequency in the rotational moment direction, such as a disc spring, is used, the elastic modulus is very high, so if a manufacturing error occurs in the spring itself, a large preload fluctuation will occur, resulting in a practical use. It is difficult to

The present invention solves these conventional drawbacks and provides a low actuator for a recording/reproducing device that is compact and suitable for high-speed seeking.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention fixes a transducer for recording and reproducing information on a recording medium using a ball bearing having an inner ring and an outer ring. A low actuator for a recording/reproducing device rotatably supported around a shaft, comprising: a first spring member that presses the inner ring in the axial direction of the fixed shaft; The low reactor actuator for a recording/reproducing device includes a second spring member that presses the outer ring in a direction opposite to the sleeve direction.

(Function) With the above configuration, the first spring member that presses the inner ring of the bearing is not affected by the rotating actuator, and transient vibrations due to the rotating operation are less likely to occur. Further, the second spring member has a larger elastic modulus than the first spring member, and therefore has a larger resonance frequency in the rotational direction of the actuator.

Therefore, not only is the outer ring of the bearing pressed to prevent rattling, but transient vibrations caused by the rotational movement of the actuator are less likely to occur, vibration of the transducer is also reduced, and high-speed seek is possible. On the other hand, since the second spring member has a relatively large elastic modulus, there are large variations in the elastic modulus due to processing accuracy, etc., but this variation is absorbed by the deflection of the first spring member that presses the inner ring of the bearing. .

(Example) Hereinafter, an example of the present invention will be described based on FIGS. 1 to 3.

1 and 2 show a first embodiment of the present invention, and the first embodiment will be described with reference to the above-mentioned FIG. 1, FIG. 2, and FIG. 4 used in the conventional example.

The actuator arm 5 has a boss portion 21 rotatably supported via ball bearings 9 and 19 around a vertical fixed shaft 7 fixed to a connecting plate 53, and a drive motor 23 consisting of a voice coil motor. It has a structure in which it rotates around a fixed shaft 7.

A magnetic head 3 as a transducer is provided at the tip side of each actuator arm 5 via a suspension 27. A magnetic disk 1 as a rotating recording medium is interposed between each of these magnetic heads 3, and these magnetic heads 3 are The structure is such that information is recorded and reproduced by moving and positioning it to an arbitrary position on the surface of the disk.

Ball bearings 9.19 are provided at the upper and lower parts of the fixed shaft 7 at a predetermined interval. The lower ball bearing 19 has an inner ring 35 and an outer ring 39. The inner ring 35 is fixed to the fixed shaft 7 while being in contact with the lower surface of a stopper part 37 formed at the lower part of the fixed shaft 7, and the outer ring 39 is fixed to the boss part 2.
The stopper 47 is fixed to the boss part 21 in a state where it is brought into contact with the top surface of a stopper 47 protruding from the bottom of the boss hole 41 of No. 1.

On the other hand, the upper ball bearing 9 has an inner ring 11 and an outer ring 1.
The inner ring 11 and the outer ring 15 are both movable in the axial direction of the fixed shaft 7 when assembled with respect to the fixed shaft 7 and the boss portion 21.

The outer ring 15 has a set screw 43 attached to the upper end surface of the boss hole 41.
The wavy washer 17 (second spring member) as a flat spring member interposed between the spring receiver 45 and the spring receiver 45 fixed thereto is pressed downward and preloaded. This results in
Prevents play in the axial direction. On the other hand, a compression coil spring 13 (first spring member) is interposed between the inner ring 11 and the stopper portion 37, and presses the inner ring 11 upward, which is the opposite direction to the direction in which the wave-like washer 17 is suppressed. The elastic modulus of the compression coil spring 13 is set smaller than the elastic modulus of the wavy washer 17. Since the wave-shaped washer 17 has a relatively large elastic modulus, manufacturing errors tend to be large, but by providing the compression coil spring 13, this bends and absorbs manufacturing errors.

A recess 48 is formed in the inner surface of the boss hole 41 facing the outer circumferential portion of the outer ring 15 of the upper ball bearing 9. A compression coil spring 49 and a pressing piece 50 are housed in the recess 48, and the outer ring 15 is magnetized. The head is pressed in three directions. This prevents play in the axial direction and allows the fixed shaft 7 and inner ring 11 to
This improves positioning accuracy.

After the ball bearing 9, the corrugated washer 17, the compression coil spring 13, etc. are assembled, the inner ring 11 of the ball bearing 9 and the fixed shaft 7 are fixed with adhesive. This fixes the clearance between the fixed shaft 17 and the inner ring 11, and prevents positioning errors when the magnetic head 3 seeks.

The wavy washer 17 with a relatively large elastic modulus that preloads the outer ring 15 of the upper ball bearing 9 has an extremely high resonance frequency in the rotational direction of the actuator arm 5 compared to the compression coil spring 13. Transient vibrations due to the rotational movement of No. 5 are less likely to occur.

As a result, vibration of the actuator arm 5 is also reduced, making high-speed seek possible. Moreover, this wave-shaped washer 17 has a large elastic modulus, and therefore the elastic modulus varies widely depending on processing accuracy, etc., but the compression coil spring 13 allows the inner ring 1 to
1 is also preloaded, and the compression coil spring 13 is deflected, thereby absorbing the above-mentioned variations.

Moreover, by adopting such a structure, no special jig or skill is required during assembly, and assembly is simple and productivity is improved.

Further, the elastic modulus of the second spring member may be set to be approximately 5 times or more, preferably 10 times or more, than the first spring member.
Experiments have shown that this is suitable for achieving the effects of the present invention.

FIG. 3 shows a second embodiment of the invention.

The difference from the first embodiment is that a compression coil spring 18 is used instead of the wavy washer 17 as a flat spring member that applies a preload force to the outer ring 15, and a stopper part 37 of the fixed shaft 7 is replaced by a ball bearing on the upper side. 9, and the compression coil spring 13 is interposed between this stop collar portion 37 and the inner ring 35 of the lower ball bearing 19.

In order to obtain a high resonant frequency, the coil spring 18 has a thicker linear line than the compression coil spring 13 and has a very small number of turns, such as one or two turns, and its elastic modulus is equal to that of the wavy washer 17. Similarly, it is set larger than the compression coil spring 13. This results in ′
Almost the same effect as the is1 embodiment can be obtained.

[Effects of the Invention] As described above, according to the present invention, the second spring member prevents axial play, making it difficult for transient vibrations to occur due to the rotational movement of the actuator. - Vibration of the sensor is also reduced, making high-speed seek possible. On the other hand, since the second spring member has a relatively large elastic modulus, there are large variations in the elastic modulus due to processing accuracy, etc., but this variation is absorbed by the deflection of the first spring member that presses against the inner ring. Since the first spring member that presses the inner ring is provided on the fixed shaft side, it is not affected by the rotating actuator, and therefore does not excite vibrations in the actuator.

[Brief explanation of drawings]

FIG. 1 is a side sectional view of the main parts according to the first embodiment of the present invention, FIG. 2 is an overall sectional view of the first embodiment, and FIG. 3 is a side view of the main parts according to the twelfth embodiment of the invention. 4 is an internal perspective view of a conventional magnetic disk device, and FIG. 5 is a sectional view of the device. 1... Magnetic disk (recording medium) 3... Magnetic head (transducer) 5... Actuator arm 7... Fixed shaft 9... Ball bearing 11... Inner ring 13... Compression coil Spring (first spring member) 15...outer ring

Claims (2)

[Claims] (1) A rotary actuator for a recording and reproducing device in which a transducer for recording and reproducing information on a recording medium is rotatably supported around a fixed shaft by a ball bearing having an inner ring and an outer ring, wherein the inner ring is connected to the A first spring member that presses in the axial direction of the fixed shaft; and a second spring member that has a larger elastic modulus than the first spring member and presses the outer ring in the opposite direction to the axial direction. A rotary actuator for a recording/playback device. (2) The rotary actuator for a recording/reproducing apparatus according to claim 1, wherein a flat spring member is used as the second spring member.