JPH04273A - Access mechanism - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an access mechanism for a storage device such as a magnetic recording or an optical recording device, that is, a device including a rotating body and an access mechanism as basic mechanical elements.

[Conventional technology]

Conventionally, in storage devices such as magnetic disks and optical disks, long access stroke drives to recording disks,
In order to satisfy both functions of fine positioning for high recording density, a coarse access mechanism and a fine access mechanism are combined, and a configuration in which the fine access mechanism is usually placed on top of the coarse access mechanism is usually adopted. In optical storage devices, the coarse access mechanism is supported by a ball hair ring linear guide and positioned with an accuracy of several tens of micrometers by a stepping motor or voice coil motor. The system uses an optical head with a resolution on the order of microns.

[Problems to be Solved by the Invention] However, with regard to the above-mentioned storage devices, there is a demand for the development of compact devices with high recording density, but conventional access mechanisms are too large to realize this. In addition, there is a drawback that the number of parts constituting the mechanism is large. For example, in a linear guide supported by a ball bearing link, even if the ball bearing element itself is small, it is several layers in size, making it inconvenient to use in an access mechanism with a stroke of several times. was there.

SUMMARY OF THE INVENTION An object of the present invention is to provide an access mechanism that is small in size, simple in structure, and has fine resolution.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention includes a housing that accommodates an access mechanism, a wire stretched between opposing surfaces of the housing, and an axial direction of the wire, It has a through-hole through which the wire is passed through at approximately the center of the side surface, can move freely on the wire passed through the through-hole, and has a sliding surface parallel to the axial direction of the wire at the lower part. , a box-shaped movable member with openings on both sides, a coarse drive means for roughly driving the movable member, provided below the movable member, on which the movable member is mounted, and the movable member slides via the sliding surface. a mounting member, one end of which is attached to the side of the mounting member, the other end of which is attached to a mounting portion formed on the inner surface of the housing, and one piezoelectric element that drives the mounting member; Two piezoelectric elements are provided parallel to the axial direction of the wire at a predetermined interval, and a piezoelectric element is provided that is mounted on the mounting portion and contacts the wire at right angles to the axial direction of the wire, and the movable It is constructed by means for suctioning and fixing the member and the mounting member via the sliding surface.

[For production]

The present invention is configured as described above, and the movable member is restrained so as to be slidable only in the axial direction of the wire by a wire passing through its center and a plane of the mounting member on which the movable member is placed. The movable member is non-contact driven and roughly positioned by a rough drive unit such as a voice coil motor, and a laminated piezoelectric element is attached to the mounting member, and the movable member is moved by electromagnetic force or electrostatic force. The movable member is suctioned and fixed to the mounting member, fine positioning is performed by a piezoelectric element, and another piezoelectric element is brought close at right angles to the axial direction of the wire to vibrate the wire, and at the time of rough access, it is attached to the mounting member. By vibrating the piezoelectric element and reducing the friction between the movable member, the wire rod, and the mounting member, positioning and tracking performance can be improved.

〔Example〕

FIG. 1 is a partial perspective view of a crushing material according to an embodiment of the present invention, and FIG. 2 is a perspective view of a main part of the embodiment of FIG.

In Figures 1 and 2, ■ is a wire, 2 is a movable part, 3 is a piezoelectric element A, 4 is a coil, 5 is a permanent magnet, 6 is a yoke,
7 is a mounting section. The coil 4, permanent magnet 5, and yoke 6 constitute a rough drive section of the linear motor.

The wire rod 1 passes through a hole provided in a movable part 2, and the movable part 2 is guided by the wire rod 2 and assembled so as to be able to smoothly move relative to each other. The movable part 2 and the mounting part 7 are in surface contact, and the axial direction of the wire 1 and the movable part 2 and the mounting part 7 are in surface contact.
Since the movable part 2 is configured parallel to the contact surface of the wire l, the movable part 2 is restrained so as to be movable only in the axial direction of the wire l.

The movable part 2 includes a coil 4 attached to the movable part 2,
Driven by a linear motor consisting of a permanent magnet 5 and a yoke 6 on the fixed side, rough positioning is performed (sensors such as a linear scale for positioning are not shown). The movable part 2 is fixed to the mounting part 7 by applying attraction force or electrostatic attraction force of the electrode. A piezoelectric element A3 is attached to the mounting portion 7, and the movable portion 2 is positioned based on a signal for fine positioning.

For example, the piezoelectric element A3 is driven by a servo signal generated from a track signal on the recording disk, and a signal recording/reproducing head (not shown) attached to the movable part 2 is caused to follow the track. The laminated piezoelectric element A3 has a length of 10Ic.
1 and has a resolution on the order of 10 nm.
In combination with the voice coil motor coarse access mechanism shown, it is possible to cover track numbers on the order of 104.

When using the attractive force of a magnet to fix the movable part 2 and the mounting part 7, a permanent magnet is built into the mounting part 7, and the coil is energized to cut off the magnetic force during rough access, and the permanent magnet is removed during fine access. The movable part 2 and the mounting part 7 can be moved without generating heat due to the magnetic force of the magnet.
and can be fixed.

This access mechanism is applicable regardless of the recording/reproducing method. A positioning or position tracking mechanism in a direction perpendicular to the recording medium can be provided as necessary. For example, a scanning tunneling microscope S T
M (Scanning Tunneling Micro
When detecting by tunnel current according to the principle of oscoρe), a laminated or cylindrical piezoelectric element that is driven in a direction perpendicular to the recording medium is mounted on the movable part 2.

FIG. 3 is a side view of a main part of an embodiment in which a piezoelectric element for slowly moving the wire 1 of FIG. 1 is provided.

In FIG. 3, 8 is a piezoelectric element B for wire vibration, and l
, 2, 3.7 are the same as in FIG.

In FIG. 3, a piezoelectric element B8 for vibration is brought into contact with the axial direction of the wire l at right angles near the fixed part of the wire l, and the piezoelectric element B8 is driven to vibrate the wire l and rough At the time of access, the piezoelectric element A3 is also caused to expand and contract, causing the movable part 2 and the mounting part 7 to vibrate relative to each other, thereby reducing the friction between the movable part 2 and the wire 1, and between the movable part 2 and the mounting part 7, and when positioning. Errors and stick-slip instability can be eliminated. The effect of such vibrations on reducing friction is known, and detailed research is being conducted [
Literature: Precision Machinery Vol. 32, No. 6, (1966).

P2O3-408).

FIG. 4 is a side view of a main part of an embodiment in which two piezoelectric elements are provided in place of the piezoelectric element 3 of FIG. 1.

FIG. 4 shows an embodiment in which two piezoelectric elements C9 and DIO are used instead of piezoelectric element A3, and these are arranged vertically parallel to the direction of expansion and contraction and at a predetermined interval. During rough positioning, voltages are applied in opposite phases to each other.

Then, one side of the piezoelectric element expands and the other contracts, so
As a result, the mounting section 7 attached thereto vibrates in a direction perpendicular to the direction of expansion and contraction of the piezoelectric element, that is, a direction perpendicular to the facing surfaces of the movable section 2 and the mounting section 7. In this case, in addition to the friction reduction effect due to the vibration described above, the following phenomenon can be utilized.

As shown in the explanatory diagram of the squeezing effect of the gas film shown in FIG. 5, when the mounting part 7 is subjected to high frequency vibration, the movable part 2
If the facing surfaces of the two are finished smoothly, the gas has viscosity in the periphery of the gas film 11 with a small gap between the two, so its movement in and out is restricted, and the movable part 2 follows due to inertia. The result is almost no vibration, as if a high-frequency volume change were caused in a sealed compressible fluid. In this case, pressure generation with respect to displacement becomes non-linear, and a gas film 11 having a pressure higher than the ambient pressure on a time average basis is formed. In FIG. 5, the movable part 2 is supported on the mounting part 7 in a non-contact manner. This phenomenon is known as the effect of compressible squeeze film [Reference: Lubrication, Vol. 18, No. 10,
(1973), P773-779].

Therefore, when the piezoelectric elements C9 and DIO are vibrated as described above, together with the vibration of the wire l, the movable part 2 is supported with low friction, and errors and stick-slips are prevented during rough positioning by the linear motor. The instability of can be eliminated. In this embodiment, the movable part 2 and the mounting part 7 are not in contact with each other, so that the wear of the movable part 2 is extremely small.

As described above, the fine positioning of the movable part 2 is performed by applying suction force to fix the movable part 2 to the mounting part 7, and then moving the piezoelectric element C9.
, it is preferable to drive the same DIO with voltages of the same phase and use the same method as the piezoelectric element A3 in FIGS. 2 and 3.

〔Effect of the invention〕

As explained in detail above, the access mechanism according to the present invention is small in size and has a simple structure, and is capable of minute positioning, so it has the effect of obtaining high resolution, and is useful for memories that require such performance. Significant effects can be expected when applied to equipment, etc.

[Brief explanation of drawings]

FIG. 1 is a partially exploded perspective view of an embodiment of the present invention, FIG. 2 is a perspective view of a main part of the embodiment of FIG. 1, and FIG. 3 is a wire rod 1 shown in FIG. 1.
FIG. 4 is a side view of a main part of an embodiment in which a piezoelectric element is provided to vibrate, FIG. It is an explanatory view of the squeeze effect of a gas film. DESCRIPTION OF SYMBOLS 1... Wire rod, 2... Movable part, 3... Piezoelectric element A,
4... Coil, 5... Permanent magnet, 6... Yoke,
7... Mounting part, 8... Piezoelectric element B, 9... Piezoelectric element C110... Piezoelectric element D, 11... Gas film. Patent applicant Nippon Telegraph and Telephone Corporation

Claims (3)

[Claims] 1. a housing, a wire stretched across opposing surfaces of the housing;
A through hole through which the wire is passed in the axial direction of the wire is provided at approximately the center of the side surface, the wire can be freely moved on the wire passed through the through hole, and a hole is provided at the bottom in the axial direction of the wire. a box-shaped movable member having a sliding surface parallel to the surface and opening on both sides; a rough drive means for roughly driving the movable member; a mounting member having a sliding surface that is in close contact with the sliding surface of the mounted movable member and on which the movable member can slide; one end is attached to the side of the mounting member, and the other end is formed on the inner surface of the housing. mounted on the mounting part, and provided parallel to the axial direction of the wire;
An access mechanism comprising: one piezoelectric element that drives the mounting member; and means for suctioning and fixing the movable member and the mounting member via the sliding surface. 2. 2. The access mechanism according to claim 1, wherein a piezoelectric element that abuts the wire is mounted on a mounting portion formed on the inner surface of the housing perpendicularly to the axial direction of the wire. 3. A claim in which two piezoelectric elements are provided between a mounting portion formed on an inner surface of the housing and the mounting member, and are mounted parallel to the axial direction of the wire at a predetermined distance from above and below. 1. The access mechanism according to claim 2.