JPH07153207A - Structure of bearing of rocking actuator in magnetic disk device - Google Patents

Abstract

PURPOSE:To attain the high speed and sure seeking operation in the manner of making the resistance torque smaller at the time of seeking operation and also reducing the error in the inclination of a rocking shaft, by forming both tip parts of the rocking shaft to the conical state and providing plural poles on these parts while abutting thereon. CONSTITUTION:A suspension arm 20 carrying a magnetic head 3 on the one end is supported by the rocking shaft 21 so as to be freely rotatably rocked. Then, the constitution is made in such a manner that both tip parts of the rocking shaft 21 are formed to the conical state parts 21a and that both thrust and radial loads are placed by means of providing the plural poles 24 on the inclined surfaces of these parts while abutting thereon. By this arrangement, the deviation in the inclination from an ideal rotary shaft does not occur and the magnetic head is accurately positioned to a desired recording track on the magnetic disk, since the rocking shaft 21 is supported by bearings at the both ends. Also, the resistances at the bearing parts are sufficiently reduced, then the miniaturization of a voice coil motor and the reduction of an average access time by the increase of seek speed are attained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing structure for an oscillating actuator in a magnetic disk.

[0002]

2. Description of the Related Art As a typical example of a bearing structure of an oscillating actuator in a conventional magnetic disk drive, there is a structure disclosed in Japanese Patent Laid-Open No. 3-152768. Next, a typical example in the prior art will be described in detail with reference to the drawings.

FIG. 3 shows a magnetic disk device 1 having a conventional rocking type actuator bearing structure. In the figure, 1a is a disk enclosure base and 1b
Is a disk enclosure cover. These create a clean space that is sealed at the top and bottom, and store the mechanical parts inside this. Reference numeral 2 is a magnetic disk having a recording track for recording information, and 3 is a magnetic head for writing or reading information on the recording track of the magnetic disk 2. A suspension arm 4 carries a magnetic head 3 at one end and a movable coil 5 constituting a voice coil motor 8 at the other end. 6 is a swing shaft, and 7 is a ball bearing, which supports the suspension arm 4 so as to be rotatable and swingable around the swing shaft 6. The voice coil motor 8 forms a magnetic gap by a lower yoke 8a, an upper yoke 8b, and a permanent magnet 8c fixed to the lower yoke 8a, and the movable coil 5 is movably arranged in the magnetic gap. When a predetermined drive current is applied to the movable coil 5, the movable coil 5 receives a driving force according to Fleming's left-hand rule, and the suspension arm 4 rotates and swings around a swing shaft 6 by a ball bearing 7 to cause the magnetic head 3 to move. Is positioned on an arbitrary recording track of the magnetic disk 2.

[0004]

The above-mentioned conventional techniques have the following problems. One of the basic performances of the magnetic disk device is the average access time, and the shorter this time, the higher the performance. The most effective way to shorten the average access time is to speed up the so-called seek operation for positioning the magnetic head 3 on a desired recording track of the magnetic disk 2. For this purpose, it is necessary to reduce the resistance when the suspension arm 4 rotates and swings around the swing shaft 6. The rolling resistance of the balls of the ball bearing 7 is the main resistance of this bearing portion. Although it is difficult to directly reduce the rolling resistance itself, the resistance acts as torque because the motion is rotational oscillating. Therefore, if the arm length of the resistance torque is reduced, the bearing portion for the rotational oscillating motion of the suspension arm 4 is reduced. The resistance of can also be reduced. However, in the bearing structure of the swing type actuator in the conventional magnetic disk device, since the bearing fits into the outer diameter of the swing shaft 6, the arm length of the resistance torque should be smaller than the diameter of the swing shaft 6. I couldn't. Further, since the swing shaft 6 has a cantilever support structure, there is a problem that an inclination error from the ideal rotation shaft occurs and resistance to the rotary swing motion increases. Further, there is a problem that the tilt error of the swing shaft 6 from the ideal rotation axis makes it difficult to accurately position the magnetic head 3 on a desired recording track on the magnetic disk 2.

The present invention solves the above-mentioned problems of the prior art by reducing the resistance torque when the suspension arm 4 oscillates about the oscillating shaft 6 to perform a seek operation, and is ideal. An object of the present invention is to provide a bearing structure of an oscillating actuator in a magnetic disk device capable of performing a reliable seek operation by reducing an error in inclination between the oscillating shaft and an actual oscillating shaft.

[0006]

In order to achieve the above object, the present invention provides a magnetic disk for recording information,
A magnetic disk device having a magnetic head for writing or reading information on or from the magnetic disk, a suspension arm carrying the magnetic head at one end, and a swing shaft for rotatably and swingably supporting the suspension arm. In the bearing structure of the oscillating type actuator, the tip end of the oscillating shaft has a conical portion, and a plurality of balls are brought into contact with the slope of the conical portion to receive both thrust and radial loads. It is characterized by being configured as follows.

Further, it is characterized in that the conical portion is a concave conical portion, and a ball is fitted into the concave conical portion so as to receive both thrust and radial loads.

[0008]

According to the above structure, both end portions of the swing shaft provided on the suspension arm have a conical portion, and a plurality of balls abut on the slopes of the conical portion to raise and lower the swing shaft. The rocking shaft is supported at both ends by supporting from
Further, since the ball contacts the conical portion, it can receive both thrust load and radial load.

Further, concave conical portions are provided at both ends of the swing shaft, and balls are fitted into and supported by the conical portions, so that the swing shaft has a structure of supporting both ends. Also, it becomes possible to receive both thrust and radial loads.

[0010]

1 is a sectional view of a magnetic disk device showing an embodiment according to claim 1 of the present invention, and FIG. 2 is a sectional view of a magnetic disk device showing the invention according to claim 2 of the present invention. Is. The members having substantially the same functions as those described in FIG. 3 have the same reference numerals.

FIG. 1 shows a magnetic disk device 1 as described in the prior art example of FIG. 3, and 2 is a magnetic disk having recording tracks on both sides for recording information. A magnetic head 3 writes or reads information to or from the recording track on the magnetic disk 2. 20 is a suspension arm which carries the magnetic head 3 at one end,
A movable coil 5 that constitutes a voice coil motor 8 at the other end
It carries. Reference numeral 21 is a swing shaft, and conical portions 21a are provided at both ends thereof. Further, a screw portion 21b is provided on the upper end side thereof, and a cutout portion 21d is provided on the lower end side thereof.
And a collar-shaped portion 21c having For the relative positioning and fixing of the suspension arm 20 and the swing shaft 21, the suspension arm 20 is provided with a through hole for accurately fitting the shaft diameter of the swing shaft 21.
In the up-down direction, the suspension arm 20 is brought into contact with the flange upper portion 21c provided on the lower end side of the swing shaft 21, and the nut 22 is fastened and fixed to the screw portion 21b provided on the upper end side. At this time, the projection 20a provided on the suspension arm 20 is accurately fitted into the notch 21d to position the suspension arm 20 and the swing shaft 21 in the rotational direction. A pivot bearing 23 is composed of a ball 24 made of a plurality of steel materials and a ball receiving plate 25. The ball receiving plate 25 forms a ball storage portion by an annular inner wall and an outer wall, and the balls 24 are preliminarily incorporated so as to be movable in the circumferential direction. The balls 24 are structured so as not to fall out in a state where they are housed in the ball receiving plate 25 during normal handling, so that there is no problem when the pivot bearing 23 is incorporated in the apparatus.
The inclined surface of the conical portion 20a formed at the upper and lower ends of the swing shaft 21 contacts the balls 24 of the pair of upper and lower pivot bearings 23 and is supported in both the radial and thrust directions. The lower pivot bearing 23 is fixed to the disk enclosure base 1a by screws 26. The upper pivot bearing 23 is firmly coupled to the lower pivot bearing 23 by a plurality of shafts 27 and has an integral structure, so that the upper and lower pivot bearings 23 are fixed to the disk enclosure base 1a.

When the voice coil motor 8 is energized, a driving force acts on the movable coil 4 to rotate the swing shaft 21 and the magnetic head 3 carried on one end of the suspension arm 20.
Is positioned on an arbitrary recording track on the magnetic disk 2. At this time, the resistance torque against the rotational motion of the voice coil motor 8 is classified into the magnetic head 3 directly received by the magnetic disk 2 and the bearing resistance torque received by the contact portion of the swing shaft 21. Conventionally, since the outer shape of the swing shaft 6 has the ball bearing 7 as described with reference to FIG. 3, the arm length of the resistance torque is not smaller than the diameter of the swing shaft 6. However, as apparent from FIG. 1, the arm length of the resistance torque in the present invention can be made smaller than the diameter of the swing shaft 21, and the resistance of the bearing portion can be remarkably reduced as compared with the conventional case. Furthermore, in the prior art, the swing shaft 6 has a cantilever structure, and the tilt error with respect to the ideal rotation axis is likely to be large, which accurately positions the magnetic head 3 on a desired recording track on the magnetic disk 2. It was a major cause of so-called seek error, which was not possible. Further, the uneven contact between the rocking shaft and the bearing caused by the tilt of the shaft generates a large resistance torque, whereas the rocking shaft 21 of the present invention has a pair of upper and lower pivot bearings 23.
Due to the both-ends supporting structure, the tilt error with respect to the ideal rotation axis is very small, so that the seek error is less likely to occur and the resistance of the bearing portion against the swinging motion is also small.

FIG. 2 is a sectional view showing an embodiment according to claim 2 of the present invention in a magnetic disk device. The same members as those described in FIG. Omit it. A concave conical portion 30a is formed at both ends of the swing shaft 30. Reference numeral 31 is a ball made of steel, and 32 is a ball receiving plate, which presses the ball 31 against the concave conical portion 30a as in the case of FIG. 1 to support the swing shaft 30. Since the ball 31 contacts the slope of the concave conical portion 30a, the arm length of the resistance torque is determined by the swing shaft 3
It can be made sufficiently smaller than the diameter of zero. According to the present invention, although the same effect as the invention according to claim 1 described in FIG. 1 is obtained, the number of the balls 31 required is one, and the cost can be reduced.

[0014]

As described above, according to the present invention, since the swing shaft is supported by the bearings at both ends thereof, deviation of the inclination from the ideal rotary shaft does not occur and the probability of seek error can be reduced. It is possible to always accurately position the magnetic head on a desired recording track on the magnetic disk. In addition, the resistance of the bearing generated on the swing shaft can be made sufficiently small, the voice coil motor can be downsized, the seek speed can be increased, and the average access time can be shortened. It has the effect of being able to.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a magnetic disk device according to claim 1 of the present invention.

FIG. 2 is a sectional view showing an embodiment of a magnetic disk device according to claim 2 of the present invention.

FIG. 3 is a sectional view showing a conventional bearing structure in a magnetic disk device.

[Explanation of symbols]

 1 Magnetic Disk Unit 4 Suspension Arm 6 Swing Shaft 20 Suspension Arm 21 Swing Shaft 21a Cone Shaped Part 23 Pivot Bearing 30 Swing Shaft 30a Concave Conical Shaped Part

Claims (2)

[Claims] 1. A magnetic disk 2 for recording information,
A magnetic head 3 for writing or reading information on the magnetic disk 2, a suspension arm 20 carrying the magnetic head 3 at one end, and a swing shaft 21 for rotatably and swingably supporting the suspension arm 20. In the bearing structure of the oscillating actuator in the magnetic disk device 1 having the following, both end portions of the oscillating shaft 21 have a conical portion 21a, and a plurality of balls 24 abut on the slope of the conical portion 21a. Thus, the bearing structure of the swing-type actuator in the magnetic disk device 1 is configured to receive both thrust and radial loads. 2. A magnetic disk 2 for recording information,
A magnetic head 3 for writing or reading information to or from the magnetic disk 2, a suspension arm 20 carrying the magnetic head 3 at one end, and a swing shaft 30 supporting the suspension arm 20 so as to be rotatable and swingable. In the bearing structure of the oscillating actuator in the magnetic disk device 1 having, the both end portions of the oscillating shaft 30 have concave conical portions 30a.
A bearing structure for an oscillating actuator in a magnetic disk device 1 characterized in that a ball 31 is fitted in a and receives both a thrust load and a radial load.