Magnetic disk drive

Abstract: A drive capable of preventing dust-containing air from standing around the inner periphery of a magnetic disk. The disk spins in such a manner as to move from a magnetic head (12) toward a head drive section (1) so as to prevent dust-containing air from standing around a spindle (10). A stream of air flows along an arm (13) supporting the head. A filters (16,17) are is located on the path along which air flows, thereby removing dust efficiently.

Description: BACKGROUND OF THE INVENTION The present invention relates to a magnetic disk drive and, more particularly, to a magnetic disk drive capable of preventing dust-containing air from standing around the inner periphery of a magnetic disk. It it a common practice with a magnetic disk drive to support a magnetic head on an arm and move the head substantially in the radial direction of a disk mounted on a spindle. As the disk spins, a stream of air is generated between the disk and the head to cause the head to float a small distance away from the disk. In this condition, desired data is recorded in or reproduced from the disk. However, the conventional disk drive described above has a problem that since the stream of air is generated at the side where the arm supporting the head is located, it entangles dust existing between the head and the disk and in the vicinity of a positioner therein while flowing toward the inner periphery of the disk, i.e., toward the spindle. As such dust-containing air stands around the spindle, the dust is apt to deposit on the disk and is likely to damage it particularly when the disk drive is started up. Another problem is that the dust cannot be removed efficiently since the head is moved by the arm substantially in the radial direction of the disk, changing the path of the air stream every moment. To absorb the dust around the disk, there has been proposed to arrange an electrostatic filter or similar implement around the spindle, as taught in, for example, Japanese Utility Model Laid-Open Publication (Kokai) No. 62-61099 and Japanese Patent Laid-Open Publication No. 2-185785. However, even the filter scheme is not fully satisfactory since the relative position of the head to the disk in the radial direction of the disk changes, changing the path along which air flows. JP-A-192987discloses a single- disk magnetic disk drive in which the disk spins in the vicinity of the magnetic head in a direction from the head towards the driving means of the arm carrying the head. A filter is located in the path of the air stream which passes between the head and the disk. This prior art disk drive however does not tackle the problem of the change of the path of the air stream when the head is moved. SUMMARY OF THE INVENTION It is, therefore, an object of the present invention to provide a reliable magnetic disk drive which maintains the interior thereof clean at all times to insure a desirable data recording and reproducing characteristic. It is another object of the present invention to provide a magnetic disk drive which prevents dust-containing air from standing around the inner periphery of a magnetic disk. It is a further object of the present invention to provide a magnetic disk drive capable of removing dust efficiently despite that the path of air flow changes with the position of a magnetic head. A magnetic disk drive of the present invention is defined in claim 1. BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description taken with the accompanying drawings in which: FIG. 1 is a plan view of a magnetic disk drive showing certain features of the magnetic disc drive of Fig. 4. FIG. 2 is a plan view showing certain features of the disk drive of Fig. 4; FIG. 3 is a plan view showing certain features of the disk drive of Fig. 4; FIG. 4 is a plan view showing an embodiment of the present invention; and FIG. 5 is a plan view of a conventional magnetic disk drive. DESCRIPTION OF THE PREFERRED EMBODIMENTS To better understand the present invention, a brief reference will be made to a conventional magnetic disk drive, shown in FIG. 5. As shown, the disk drive has a spindle 30 driven by a motor, not shown, magnetic disks 31 mounted on the spindle 30 at equally spaced locations along the axis of the spindle 30, magnetic heads 32 each facing a respective disks 31, arms 33 each supporting a respective head 32, and head drive sections 35 each rotating a respective arm 33 to thereby move the associated head 32 substantially in the radial direction of the disk 31. In this configuration, each disk 31 is caused to spin clockwise by the spindle 30, as indicated by an arrow P in the figure. As a result, a stream of air is generated between the disk 31 and the associated head 32 to cause the head 32 to float a small distance away from the disk 31. In this condition, desired data is recorded in or reproduced from the disk 31.. However, the conventional disk drive described above has some problems left unsolved, as discussed earlier. Specifically, the stream of air is generated at the side where the arm 33 supporting the head 32 is located. Consequently, the air stream entangles dust existing between the head 32 and the disk 31 and in the vicinity of a positioner, not shown, therein while flowing toward the inner periphery of the disk 31, i.e., toward the spindle 30. As such dust-containing air stands around the spindle 30, the dust is apt to deposit on the disk 31 and is likely to damage it particularly when the disk drive is started up. Moreover, the head 32 is moved by the arm 33 substantially in the radial direction of the disk 31, changing the path of the air stream every moment. This prevents the dust from being removed efficiently. To absorb the dust around the disk 31, there has been proposed to arrange an electrostatic filter or similar implement around the spindle 30. However, even this kind of implement cannot remove the dust satisfactorily. Referring to FIG. 1, a magnetic disk drive will be described which is free from the problems discussed above. As shown, magnetic disks 11 are securely mounted on a spindle 10 at equally spaced locations along the axis of the spindle 10. Magnetic heads 12 are each positioned to face a respective disk 11 and supported by a respective arm 13. The arm 13 is driven by a respective head drive section 15 to move the associated head 12 substantially in the radial direction of the disk 11. In Fig. 1, the disk 11 spins counterclockwise, as indicated by an arrow P in the figure. As a result, a stream of air is generated between the disk 11 and the head 12 to cause the head 12 to float a small distance away away from the disk 11. In this condition, desired data is recorded in or reproduced from the disk 11. Since the disk 11 spins counterclockwise, the stream of air is generated at the side where the tip of the head 12 is located, i.e., at the side remote from the head drive section 15. Consequently, the air stream flows from the head 12 toward the head drive section 15, entraining dust existing between the head 12 and the disk 11 along the arm 13. This is successful in preventing air containing dust from standing around the inner periphery of the disk 11. In figure 2, the same constituents as the constituents shown in FIG. 1 are designated by the same reference numerals, and a detailed description thereof will not be made in order to avoid redundancy. As shown, the disc drive of Fig. 2 includes an electrostatic filter, or small pressure loss filter, 16 located on the path along which the stream of air flows, as described in relation to Fig. 1. The filter 16 is capable of collecting even dust floating in air since it is implemented by an intertwined structure of filaments which are weakly statically electrified. Further, since the filter 16 has only small pressure loss, a great amount of air is allowed to flow therethrough, promoting efficient dust collection. An embodiment of the present invention will be described with reference to FIG. 4. In figures 3 and 4, the same constituents as the constituents shown in FIG. 2 are designated by the same reference numerals, and a detailed description thereof will not be made in order to avoid redundancy. FIGS. 3 and 4 are respectively indicative of a condition wherein the head 12 adjoins the inner periphery of the disk 11 and a condition wherein it adjoins the outer periphery of the disk 11. In the condition shown in FIG. 3, air flows along the side of the disk 11 remote from the spindle 10 while, in the condition shown in FIG. 4, it flows along the other side of the disk 11 which faces the spindle 10. As a result, the path along which air flows changes, following a change in the position of the head 12. In this embodiment of Fig. 4, another electrostatic filter 17 is located on the path along which air flows when the head 12 adjoins the outer periphery of the disk 11, as shown in FIG. 4. With this embodiment, it is possible to remove dust even more positively than with the disc drive of Fig. 2 and 3. In summary, it will be seen that the present invention provides a magnetic disk drive which prevents air containing dust from standing around the inner periphery of a magnetic disk, and removes dust efficiently despite that the path along which air flows changes with the position of a magnetic head. Hence, the interior of the disk drive remains clean at all times, insuring reliable recording and reproduction of data.

Claims: A magnetic disk drive comprising: a plurality of magnetic disks (11) mounted on a spindle (10) at equally spaced locations on an axis of said spindle (10) and driven to spin by said spindle; a plurality of magnetic heads (12) each facing a respective magnetic disk (11) for selectively writing or reading data in or out of said magnetic disk (11); a plurality of arms (13) supporting a respective magnetic head (12); each of said plurality of magnetic heads (12) being caused to float a predetermined distance away from said magnetic disk (11) by a stream of air flowing between said magnetic disk (11) and said magnetic head (12); head drive means (15) for driving said plurality of arms (13) in a rotary motion around a head drive section (15), whereby said disks (11) spin in the vicinity of the heads in a direction from said magnetic heads (12) towards said head drive section (15); each of said arms being such that said stream of air flows along a first side of said magnetic arm (13) towards said head drive section (15) when said arm is in a first position where the associated head adjoins the inner periphery of the disk and said stream of air flows along a second side of said magnetic arm (13) towards said head drive section (15) when said arm is in a second position where the associated head adjoins the outer periphery of the disk, said first side of said arm (13) being remote from said spindle (10) and said second side of said arm (13) being opposite said first side and facing said spindle (10); and a first filter (16) located in the vicinity of said magnetic disks on a path along which said stream of air flows when the corresponding arm is in said first position; and a second filter (17) is located in the vicinity of said magnetic disk on a path along which said stream of air flows when the corresponding arm is in said second position. A magnetic disk drive as claimed in claim 1, characterized in that said first (16) and second (17) filters are electrostatic filters or small pressure loss filters.

Inventors: HARUYAMA HIROYUKI, HARUYAMA, HIROYUKI, HARUYAMA, HIROYUKI, C/O NEC CORPORATION
Applicants: NIPPON ELECTRIC CO, NEC CORPORATION
Application year: 1993
Main classification: G11B25
IPC codes: G11B25, G11B33