JPS6334138Y2 - - Google Patents

Description

Detailed Description of the Invention This invention relates to a swing arm type magnetic head positioning device which positions a magnetic head relative to a magnetic disk by swinging a head arm to which a magnetic head is attached in the radial direction of the magnetic disk.

Conventionally, in magnetic disk devices, a swing arm type head positioning device as shown in FIG. 1 has been widely used as a device for positioning a magnetic head on an arbitrary information track on a magnetic disk. In this device, the magnetic head 3 is connected to the swinging arm 2.
The movable element 4 of the electromagnetic actuator is attached to the other end of the arm. The swinging arm has an electromagnetic actuator 4 centered around a rotating shaft 6.
and 5 to position the magnetic head 3 to any information track on the magnetic disk.
Generally, a closed loop control method using position signals read out by a magnetic head is used for this positioning. Therefore, if there is a gap in the radial direction between the swing arm 2 and the rotating shaft 6, the positioning error of the magnetic head increases, and sometimes the servo system oscillates, making highly accurate positioning impossible. In particular, when a ball bearing is provided in a portion of the swing arm 2 that contacts the rotating shaft 6, the gap between the ball and the inner and outer rings becomes a problem. Therefore, in conventional devices, as shown in FIG. 2, a method has been adopted in which the inner ring is pressed using a preload spring.

In FIG. 2, a fixed shaft 8 is fixed on a base 7, and a swing arm 2 is rotatably supported by a cylinder 9 and a pair of ball bearings 11 and 12. The preload spring 13 pushes down the inner ring of the ball bearing 11, and further pushes down the inner ring of the ball bearing 11.
By pushing down the outer rings of No. 2, the balls are attached so that each of the inner and outer rings and the balls are brought into close contact with each other. The inner ring of the ball bearing 12 is tightly press-fitted into the fixed shaft 8, but there is a slight gap between the inner ring of the ball bearing 11 and the fixed shaft 8 so that it can be easily pushed down by the preload spring 13. is provided. This gap reaches several microns (μm) with normal dimensional accuracy, and higher dimensional accuracy is required for more accurate positioning, which also poses a problem in terms of cost.

An object of the present invention is to provide a head positioning device that can reduce the influence of the gap without increasing the dimensional accuracy of the rotary bearing.

The device of the present invention is a swinging arm type head positioning device that positions the magnetic head at a predetermined position on a magnetic recording medium by rotating the swinging arm portion on which the magnetic head is mounted around a fixed axis. a ball bearing having an outer ring and an inner ring for rotatably supporting the swing arm part on the fixed shaft; one recess on the outer periphery of the fixed shaft facing the inner ring of the ball bearing; The present invention is characterized in that the protrusions are provided at equal intervals, and a spring means for pressing the inner ring of the ball bearing is accommodated in the recess.

Hereinafter, the apparatus of the present invention will be explained in detail with reference to Examples. FIG. 3 is a diagram for explaining an embodiment of the present invention. FIG. 3a is a schematic diagram showing a cross section near the fixed shaft, showing the fixed shaft 8, the bearing 15 of the swinging arm, and the cylinder 9. In this case, there is a recess 1 on the fixed shaft side in the circumferential area where the fixed shaft and the swinging arm should come into contact.
9 is provided, in which spring means 20 are provided. This spring means is connected to the bottom of the recess 19 and the bearing 1
5, and has the effect of minimizing the play between the fixed shaft and the swinging arm. In this embodiment, two protrusions 17 and 18 are further provided at equal intervals on the same circumference as the recess of the fixed shaft. This structure consists of a fixed shaft 8 and a cylinder 9.
This is useful because the center of the image can be accurately located.
In this case, the fixed shaft and the spring means come into contact with each other at three locations on the two protrusions 17 and 18, and play between them can be effectively suppressed.

3b and 3c show two specific examples of the spring means, FIG. 3b using a leaf spring 21, and FIG. 3c showing a coil spring 22 and a contact 2.
3 is used.

The device of the present invention can be applied in various ways other than the above embodiments. That is, the recesses and the spring means may be provided at a plurality of locations, or may be provided on the swing arm side. However, from the viewpoint of cost and manufacturing technology, it is better to provide the minimum required number on the fixed shaft side.

As described above, the head positioning device of the present invention can realize highly accurate head positioning using relatively simple means.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining a swinging arm, FIG. 2 is a diagram for explaining a conventional swinging arm, and FIG. 3 is a diagram for explaining one embodiment of the present invention. . 1... Magnetic disk, 2... Swinging arm, 3...
...Magnetic head, 4...Mover, 5...Stator, 6
...Rotating axis, 7...Base, 8...Fixed axis, 9...
Cylindrical, 11 and 12...Ball bearing, 1
3...Preload spring, 15...Bearing, 17 and 1
8... protrusion, 19... recess, 20... spring means,
21...Plate spring, 22...Coil spring, 23...
contact child.

Claims (1)

[Claims for Utility Model Registration] A swinging arm type head positioning device that positions a magnetic head at a predetermined position on a magnetic recording medium by rotating a swinging arm portion on which a magnetic head is mounted around a fixed axis. The ball bearing has an outer ring and an inner ring for rotatably supporting the swing arm portion on the fixed shaft, and a recess is provided on the outer periphery of the fixed shaft opposite to the inner ring of the ball bearing. A head positioning device characterized in that two protrusions are provided at equal intervals, and a spring means for pressing the inner ring of the ball bearing is accommodated in the recess.