JPH07101489B2 - Head crash detector for magnetic disk unit - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a detection device for detecting a collision (head crush) between a disk and a magnetic head of a magnetic disk device, and more specifically to a measurement disk and a magnetic disk. The present invention relates to a head crash detection device that determines a head crash by detecting dust generated when a head collides.

[Prior Art] In the conventional head crash detection device, all of the inside of the shroud into which the measurement disk is thrust is based on the fact that dust is always generated when the measurement disk and the magnetic head collide. A head crash was detected by counting dust with a dust counter.

[Problems to be Solved by the Invention] However, when the area of the measurement disk in the shroud becomes large, dust due to head crash diffuses throughout the measurement disk, and the dust counter collects and detects the dust. Becomes difficult. Further, it is very difficult to detect a small amount of dust change due to a weak head crash between the measuring disk and the magnetic head. Further, when the rotation of the measuring disk is stopped, it is easily affected by the environment around the shroud, and the head crash detection time becomes long.

An object of the present invention is to provide a head crash detection device that has a short head crash detection time and high detection accuracy.

[Means for Solving the Problems] In order to achieve the above object, the head crash detecting device according to the present invention has the following features. That is, the present invention has a mechanism for rotating the measuring disk,
In a head crash detection device for a magnetic disk device, a shroud that encloses the entire measurement disk, a cutout portion for inserting a magnetic head, a dust collection groove, and a dust collection space communicating with this groove. And a shroud having a dust counter connection port communicating with the dust collecting space, and a clean air supply mechanism for supplying clean air into the shroud.

[Operation] When the measurement disk and the magnetic head cause a head crash, dust is always generated. The dust collects in the dust space through the groove of the shroud due to the flow of air accompanying the rotation of the measuring disc. The dust is sucked into the dust counter by negative pressure from the dust counter connection port communicating with the dust collecting space. Then, the number of dust is measured by the dust counter, and it is possible to know from this whether or not the head crash has occurred. Further, by supplying clean air into the shroud by the clean air supply mechanism when the measurement disk is stopped, it is possible to prevent dust from entering the shroud from the outside of the shroud. further,
The dust counter can be calibrated by counting dust while supplying clean air.

[Embodiment] Next, an embodiment of the present invention will be described with reference to the drawings.

The drawing is an exploded perspective view showing the structure of an embodiment of the present invention. In the head crash detecting device of this embodiment, the lower plate 2, the side wall 3, and the acrylic lid 7 form a shroud, and the shroud can enclose the measuring disk 6. The lower plate 2 is provided with a notch 8 for inserting the magnetic head 10. Further, on the lower plate 2 on both sides of the cutout 8, the dust collecting grooves 1a and 1b and the dust collecting spaces 4a and 4b communicating with the grooves 1a and 1b, respectively.
And are provided.

The dust collecting grooves 1a and 1b are preferably formed along the rotation direction (circumferential direction) of the measuring disk 6. Dust counter connection ports 5a and 5b for connecting an external dust counter communicate with the dust collection spaces 4a and 4b, respectively. Further, the side wall 3 is provided with a clean air supply port 9 for supplying clean air.

Next, the operation of this head crash detection device will be described. First, the measurement disk 6 is set inside the shroud, the acrylic lid 7 is closed, and the dust counter connection port 5a,
Connect the dust counter to 5b. Next, the magnetic head 10 is inserted into the notch 8. And the magnetic head from below
10 is set on the measuring disk 6. After completing the setting of the magnetic head 10, rotate the measuring disk 6 in the direction of arrow A,
The measuring head 10 is levitated from the measuring disc 6. If a crash occurs between the measuring disk 6 and the magnetic head 10 in this state, dust is generated. Since the measuring disk 6 rotates in the direction of arrow A, dust passes through the groove 1b and collects in the dust collecting space 4b. Since the groove 1b and the dust collecting space 4b are provided near the notch 8, the dust is efficiently collected in the dust collecting space 4b without being diffused into the entire shroud as compared with the conventional device.
Dust that has reached the dust collection space 4b is connected to the dust counter connection port.
5b is sucked into the dust counter by negative pressure. Then, the number of dust is measured in the dust counter.

When the rotation of the measuring disc 6 is stopped, clean air 9a is supplied from the clean air supply port 9 into the shroud,
Eliminate environmental dust entering the shroud interior from the outside (especially through the notch 8). When the measurement disk 6 starts rotating, the supply of clean air is stopped.

When the measuring disk 6 is rotated in the direction of arrow B, the dust passes through the groove 1a, passes through the dust collecting space 4a, and is sucked into the dust counter from the dust counter connection port 5b.

If dust is measured while supplying clean air while the measurement disk is stopped, the dust counter can be calibrated without head crash and without being affected by the external environment. That is, the dust counter can be calibrated with the dust counter still connected to the shroud.

In the drawing, only three of these grooves are shown in order to make the structure of the grooves 1a and 1b easy to understand, but a larger number of these grooves may be formed.

[Effect of the Invention] As described above, according to the present invention, the dust generated by the head crash is efficiently collected in the dust collecting space through the groove of the shroud, and then the dust is sucked into the dust counter. A clean air supply mechanism supplies clean air into the shroud. With these,
The present invention has the following effects.

(1) The dust generated by the head crash can be collected in the dust collection space without being diffused in the entire shroud, that is, the entire circumference of the measurement disk, and the dust can be efficiently sent to the dust counter. Therefore, the dust measurement time can be shortened and the measurement accuracy can be improved.

(2) By supplying clean air, dust outside the shroud does not enter the inside of the shroud, so erroneous measurement of dust can be prevented.

(3) By measuring dust while supplying clean air, the dust counter can be calibrated with the dust counter attached.

[Brief description of drawings]

The drawing is an exploded perspective view showing the structure of an embodiment of the present invention. 1a, 1b ... Groove 2 ... Lower plate (part of shroud) 3 ... Side wall (part of shroud) 4a, 4b ... Dust collection space 5a, 5b ... Dust counter connection port 6 ... Measurement circle Plate 7 ... Acrylic lid (part of shroud) 8 ... Notch 9 ... Clean air supply port 10 ... Magnetic head

Claims (1)

[Claims] 1. A head crash detection device for a magnetic disk device, comprising a mechanism for rotating a measuring disc, said shroud enclosing the entire measuring disc, and a cutout portion for inserting the magnetic head, A shroud having a groove for dust, a dust collecting space communicating with the groove, and a dust counter connection port communicating with the dust collecting space, and a clean air supply mechanism for supplying clean air into the shroud. A head crash detection device comprising: