JPS60140573A - Positioning mechanism of magnetic head - Google Patents

Abstract

PURPOSE:To remove relative slip between an inner ring of bearing and a rotation shaft without spoiling easiness of disassembling and assembling by providing a preloading device that fixes a bearing holding member the inner diameter face of which fits to the rotation shaft to the inner ring of the bearing and acts in radial direction and a preloading device that preloads in axial direction. CONSTITUTION:When driving current is applied to a voice coil motor consisting of a voice coil 4 and a permanent manget fixed on a supporting base 5, turning force is given by the permanent magnet to the voice coil 4, and a supporting body 3 is rotated around a rotation axis 6 through bearings 7a, 7b. A head arm 2 attached to the supporting body 3 is rotated, and the magnetic head 1 is positioned to a desired track on a magnetic disk. Under this condition, a preloading spring 14 provided on the lower face of a bush 15 acts to energize the inner ring of the bearing 7b in axial direction through the bush 15. Accordingly, radial gaps between inner and outer rings of bearings 7a, 7b and bearing balls 21 are eliminated. Inclination of the supporting body 3 caused by change of temperature is reduced remarkably.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a magnetic head positioning mechanism, and more particularly to a rotary magnetic head positioning mechanism suitable for improving positioning accuracy. [Background of the Invention] As shown in FIG. 1 shows a rotary magnetic head positioning mechanism according to the prior art.

A head arm 2 carrying a magnetic head 1 is fixed to a support 3, and a voice coil 4 is attached to the opposite side of the support 3. The rotating shaft 6 is rotatably supported by bearings 7a and 7b attached to the support base 5, and the support body 3 is fixed to the rotating shaft 6. A bushing 8 is fixed to the outer ring of the bearing 7a, and a small hole is provided in the horizontal direction in a part of the support base 5 that corresponds to the bushing 8, and a pusher 9 is inserted into the small hole. A preload spring 10 is buried therein. Further, a preload spring 14 is provided on the upper surface of the bush 8, and presses the spring 14 downward.

FIG. 2 is a sectional view taken along line A--A in FIG. 1. The states of the bushing 8 and pusher 9 will be explained with reference to this figure.

As shown in the figure, the bushing 8 has two protrusions 12.1.
3 is formed, so that the pusher 9 can fit into the recess 1 of the bush 8.
1, the bushing 8 comes into contact with the support base 5 at three points: the recess 11 and the projections 12 and 13. In this state, the pressing force of the preload spring 14 acts on the upper surface of the bush 8, and the outer ring of the bearing 7a is pressed in the axial direction.
The radial clearance of the bearing existing between the inner and outer shafts of a and 7b and the bearing ball 21 is removed. As a result, the rotation axis 6
This prevents vibration and enables precise positioning of the magnetic head.

However, in general, the support base 5, the bearing 7a, and the bushing 8
The materials of the bearings are different, and in the method of removing the radial clearance of the bearing as described above, the difference in thermal expansion coefficient between the support base 5 and the bushing 8 occurs when starting the equipment or when the ambient temperature changes. 〇 changes to the fitting gap. This change in the fitting gap ΔQ causes the entire support body 3 to be inclined with respect to the support base 5, resulting in so-called thermal off-track, which reduces the positioning accuracy of the magnetic head.

By the way, the rotating shaft 6 and the inner rings of the bearings 7a and 7b are bonded together.
They are engaged by fitting with a very small gap. If they are engaged by adhesive, it will be difficult to disassemble and reassemble the bearings 7a, 7b, rotating shaft 6, support base 5, etc. when trying to disassemble them for reasons such as replacing the magnetic head after the bearings are assembled. It will be damaged by external force during disassembly.

In addition, in the case of fitting with a small gap, disassembly and assembly are easy, but since the degree of engagement between the rotating shaft 6 and the inner rings of the bearings 7d and 7b is low, the rotating shaft 6 and the bearings 7a and 7b are closed when the device is driven. Relative slippage occurs in the rotational direction between the inner ring and the so-called radial runout of the bearing, which reduces the magnetic/rad positioning accuracy.

[Purpose of the invention]

The purpose of the present invention is to eliminate the drawbacks of the prior art as described above,
A rotary magnetic head positioning mechanism that eliminates the radial clearance of the bearing without tilting the rotating shaft due to temperature changes, and eliminates relative slip between the inner ring of the bearing and the rotating shaft without impairing ease of disassembly and assembly. Our goal is to provide the following.

[Summary of the invention]

In order to achieve the above object, the present invention provides a head arm having a magnetic head mounted on one end, a rotational driving force generating means for generating a rotational driving force, and a head arm having a magnetic head mounted on one end thereof, a rotational driving force generating means for generating a rotational driving force, and a rotational driving force generating means for generating a rotational driving force between the other end of the head arm and the rotational driving force generating means. A magnetic head positioning mechanism that includes a magnetic head support that is connected to a rotating shaft and rotatably supports the magnetic head, and a support base that supports the rotating shaft via a bearing, the inner diameter surface of which is connected to the rotating shaft. A bearing holding member that is fitted with the bearing holding member is fixed to the inner ring of the bearing, and a preloading means that acts in the radial direction between the bearing holding member and the rotating shaft, and a preloading means that preloads the bearing holding member in the axial direction,
A feature is that the bearing holding member and the rotating shaft are engaged with each other through a protrusion and a notch formed therein.

[Embodiments of the invention]

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

FIG. 3 is a sectional view showing a magnetic head positioning mechanism according to an embodiment of the present invention.

A head arm 2 and a voice coil 4 are attached to the support 3 in opposite directions, and the head arm 2 carries the magnetic head 1. The rotary lll16 is rotatably supported by bearings 7a and 7h attached to the base 5, and is fixed to the three-piece rotary support 1iII16. Bearing 7b
A bushing 15 is fitted into the inner ring. A small hole is provided in a part of the rotating shaft 6 corresponding to the bush 15, and a presser metal 16 and a preload spring 17 are embedded therein. A preload spring 14 is provided on the lower surface of the bushing 15.
The inner ring of the bearing 7b is urged in the axial direction via the inner ring of the bearing 7b.

The magnetic head positioning mechanism configured in this way includes a permanent magnet (
When a drive current rl is applied to the voice coil motor (not shown), the voice coil 4 receives a rotational force from the permanent magnet, and the support body 3
It rotates around the rotating shaft 6 via a and 7b. As a result, the head arm 2 mounted on the support 3 rotates, and the magnetic head 1 is positioned at a desired track on the magnetic disk (not shown).

Using FIG. 4 which shows the sectional view taken along the line B-B in FIG.
The state of the bushing 15 will be explained.

The pusher 16 embedded in the small hole of the rotating shaft 6 presses the bush 15 by the elastic force of the preload spring I7.

This pressing point is 18. The rotating shaft 6 has a shape in which the side surface of a cylinder whose diameter is the inner diameter of the bushing 15 is shaved, and three vertices are formed at approximately equal angles, so that the rotation speed is 1 fill 116.
The bush 15 and the bush 15 touch at three points: the suppression point 18 and the apex 19.20.

In this state, the preload spring 1/I provided on the lower surface of the bushing 15 acts and biases the inner ring of the bearing 7b in the axial direction via the bushing 15, so that the inner and outer shafts of the bearings 7a and 7h and the bearing The radial gap existing between the ball 21 and the ball 21 is removed.

In the radial gap removal mechanism configured as described above, the components, particularly the bushing 15, which cause the rotating shaft 6 and the entire support body 3 to tilt due to temperature changes, are significantly smaller than the conventional ones. Therefore, in this embodiment, the difference in thermal deformation among the rotating shaft 6, the bearing 7b, and the bushing 15￥f when the temperature changes is reduced, and the tilt 4'1 of the support body 3 due to the temperature change is reduced.
can be significantly reduced, eliminating the heat-off 1-rank problem. I can do two things. Note that the rotating shaft 6, bearings 7a, 7b, bushing 15, etc. are made of the same material.
It is clear that the difference in thermal deformation disappears and the occurrence of thermal off-trunk can be almost completely prevented.

In addition, as shown in FIG.
2 is provided and engages with a notch provided in the bush 15. Therefore, it is possible to prevent the inner ring of the bearing 7b from rotating, and to prevent relative slippage between the rotation ΦIIIG and the bearing 7a in the rotational direction, thereby preventing the magnetic head positioning accuracy from becoming low.

Furthermore, according to this embodiment, the rotating shaft 6 and the bearings 7a, 7b
Since it is possible to create a structure that does not cause the above (1 line) burr without modifying theory 1 of the above, it is possible to make an IA measure with good disassembly and assembly.

FIG. 5 is a partial cross-sectional view of another embodiment of the invention. The difference from the above embodiment lies in the relative slip prevention mechanism. That is, in this embodiment, the bottle 22 is provided in the bush I5 fixed to the inside of the bearing 7b, and the rotation 4i111 G
It is configured to prevent relative slippage between the rotating shaft 6 and the inner ring of the bearing 7b by engaging with a notch formed in the inner ring.

In each of the above embodiments, the preload spring 7 acting between the rotating shaft 6 and the bushing 15 is provided at a position corresponding to the lower bearing 7b, but the preload spring 7 is provided at a position corresponding to the lower bearing 7a. It is also possible to provide it at a position where Furthermore, although springs were used as preload means in the radial and axial directions,
It is clear that other preload means can achieve the same effect.

〔Effect of the invention〕

As explained above, according to the rotary magnetic head positioning mechanism of the present invention, the radial clearance of the bearing can be removed without causing the rotation axis to tilt due to temperature changes, and the bearing can be removed without impairing the ease of disassembly and assembly. It is possible to eliminate slippage and I slip between the inner ring and the rotating shaft.

It is possible to improve positioning accuracy.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing a rotary magnetic head positioning mechanism according to the prior art, FIG. 2 is a cross-sectional view taken along line A-A in FIG. 1, and FIG. 3 is a rotary magnetic head according to an embodiment of the present invention. FIG. 4 is a sectional view taken along line R-B in FIG. 3, and FIG. 5 is a partial sectional view showing another embodiment of the present invention. 3: Support body, 6: Rotating shaft, 7a, 7b: Bearing, 14.1
7: T-pressure spring, 15: Bush, 16: Push metal, I8:
Push point, 19, 20: vertex, 22: pin. Figure 1/Figure 2 Figure 3a Continuation of Cow Figure Page 1

Claims (2)

[Claims] (1) A head arm having a magnetic head mounted on one end, a rotational driving force generation means for generating a rotational driving force, and a rotating shaft of the rotational driving force generation means connected to the other end of the head arm, In a magnetic head positioning mechanism including a magnetic head support that rotatably supports a head and a support base that supports the rotating shaft via a bearing, a bearing holding member whose inner diameter surface fits with the rotating shaft is provided. A preload means is provided that is fixed to the inner ring of the bearing and acts in a radial direction between the bearing holding member and the rotating shaft, and a preload means that preloads the bearing holding member in the axial direction. magnetic head positioning mechanism. (2) A notch or a protrusion is provided in a part of the bearing holding member, and a protrusion or a notch is provided in a part of the rotating shaft, and these notches and the protrusion are engaged. A magnetic head positioning mechanism according to claim 1, characterized in that: