JPS6356632B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic disk device which is an external storage device for a computer, and more particularly to a magnetic head positioning mechanism of a magnetic disk device.

Conventionally, in a rotating arm type magnetic disk device configured to position a magnetic head at a desired position on a magnetic disk surface by rotation of a magnetic head arm having a magnetic head fixed to the tip thereof, a rotational force is applied to the magnetic head arm. A pair of cams and cam rollers are often used to provide this. An example of this positioning system will be explained with reference to FIG. 1. A magnetic head 1 is fixed to a magnetic head arm 2, and the magnetic head arm 2 is provided with a pivot shaft 3 so that it can freely rotate around this axis. It's summery. A cam roller 4 (in this case, a ball bearing) is attached to the magnetic head arm 2, and is in contact with the outer peripheral curved surface of a cam 5 attached to the rotating shaft of the step motor 6 by the initial rotational force of a spring 7. The pivot rotation center axis, the roller rotation center axis, and the step motor rotation center axis are all configured to be parallel to each other. In the positioning system constructed in this manner, when the step motor is rotating steadily, the cam roller rotates and moves on the curved outer circumferential surface of the cam, and no slipping occurs on the contact surfaces thereof. However, when the step motor stops from steady rotation, the cam undergoes transient vibration, causing slippage at the contact surface between the cam and the cam roller. This slippage generates dust from the contact surface, which enters the small gap between the magnetic head and the magnetic disk, resulting in a head crash.

The present invention provides a magnetic head positioning mechanism that eliminates the slippage of the cam and cam roller during the transient state of the step motor by magnetizing the cam and the cam roller in opposite directions along their axial directions, and that does not generate dust. The purpose is to

The present invention has a cam that is magnetized along the axial direction and has a curved outer peripheral surface, a rotation center axis that is parallel to the rotation axis of the cam, and a rotation direction opposite to the cam along the direction of the rotation center axis. The cam roller is magnetically magnetized to the cam roller, and the cam and the cam roller are always attracted to each other, thereby eliminating slippage between the cam and the roller.

Embodiments of the present invention will be described below with reference to the drawings.

The present invention focuses on the fact that the magnetic force caused by the magnetization of the cam and the cam roller generates an attractive force on the contact surface between the cam and the cam roller, thereby preventing the cam and the cam roller from slipping. First, the external appearance of the magnetic head positioning mechanism in this embodiment is similar to that shown in FIG. However, the first
The cam roller 4 and cam 5 shown in the figure are magnetized in opposite directions along their axial directions. Second
The figure shows a cross-sectional view of the contact portion between the cam roller 4 and the cam 5. A cam roller 4 (a ball bearing in this example) is inserted into a roller shaft 9 and fixed to the magnetic head arm 2 with a fixing screw 11 through a spacer 10. The cam 5 is fixed to the rotating shaft of a step motor 6 with a nut 12, and the step motor 6 is attached to a magnetic disk device main body 8.
The cam 5 in this example is magnetized so that the upper surface is a north pole and the lower surface is a south pole, and the cam roller 4 is magnetized so that the upper surface is an south pole and the lower surface is a north pole. Due to this magnetic force, the outer circumferential cylindrical surface of the cam roller 4 is attracted to the outer circumferential curved surface of the cam 5, and even in a state of transient vibration of the step motor, no slipping occurs on the contact surface, and no dust is generated.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a magnetic head positioning mechanism in a rotating arm type magnetic disk device, and FIG. 2 is a longitudinal sectional view of a cam and a cam roller contact portion. 1...Magnetic head, 2...Head arm, 4...
...Cam roller, 5...Cam, 6...Step motor, 8...Magnetic disk device main body.

Claims (1)

[Claims] 1. In a magnetic disk device in which a magnetic head at the tip of the head arm moves as a cam roller pivotally supported by a head arm follows the movement of a cam attached to a step motor, the cam and the cam roller move along their respective axial directions and with respect to each other. A magnetic head positioning mechanism characterized by being magnetized in opposite directions.