JPH0143384B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an automatic loading mechanism for a floating head slider, and more particularly to an automatic loading mechanism for a slider suitable for separating a slider stuck to a disk surface while it is stationary without damage. It is something.

[Background of the invention]

The floating head slider stably floats about 0.2 μm above the disk surface when rotating at a constant speed, so a pressing force is always exerted on the disk surface.
Furthermore, in order to achieve such microlevitation, the disk surface and slider surface are polished to a very smooth finish. Therefore, when the disk is stationary, the two surfaces tend to stick together, which is a major technical problem regarding sliders. In the conventional automatic slider loading mechanism, the slider is raised and lowered by an acting force that is substantially perpendicular to the disk surface. Therefore, if the attracted slider is lifted from the disk surface, an accident may occur in which the slider or the slider mounting member is destroyed. There were flaws.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an automatic loading mechanism for a slider that solves the above-mentioned drawbacks by having a simple structure for separating the slider and the disk even if adhesion occurs between the slider and the disk.

[Summary of the invention]

The slider automatic loading mechanism of the present invention includes:
In addition to using a shape memory alloy based on thermoelastic martensite in the drive part of the automatic loading mechanism for a slider with a head, the slider adhering to the disk surface can be moved not in one degree of freedom but in multiple degrees of freedom with twisting. The feature is that loading is performed by peeling off from the disk surface by operation.

Here, shape memory alloys, particularly omnidirectional (reversible) shape memory alloys invented in recent years, will be explained. In the martensitic transformation, there is a regular crystal alignment relationship between the crystal lattice of the parent phase and the crystal lattice of martensite, and the chemical free energy of both phases is such that the martensitic phase is on the low temperature side of the transformation point, and the martensite phase is on the high temperature side. Since the parent phase is low and stable, it is possible to utilize the shape change associated with martensitic transformation (reverse transformation) by applying temperature changes above and below this transformation point.

In the present invention, this temperature control is performed using Joule heating based on self-resistance, but in this case, instead of heating the entire shape memory alloy at the same time, the current density difference is created in the current passing through the shape memory alloy. Keep it. Therefore, there is a time lag in reaching the transformation temperature, and even a flat shape memory alloy can perform complex three-dimensional movements. This operation allows the attracted slider to be peeled off from the disk surface.

[Embodiments of the invention]

Embodiments of the automatic loading type head slider mechanism of the present invention will be described below with reference to FIGS. 1 to 4. FIG. 1 shows a perspective view of the support of a slider with a magnetic head. On the rotating magnetic disk 1 is a magnetic head 2 for reading and writing data.
is attached to the rear end of the slider 3. This slider 3 is attached to the tip of a load arm 5, which is a pressing member that has an elastic force that presses against the magnetic disk surface with a constant pressure via a gimbal member 4, and furthermore, this load arm 5 has its root portion pressed against the magnetic disk surface. The guide bar 14 is connected to the tip of a movable guide bar 14 that allows access to any track of the guide bar 14. On the other hand, in order to lift the load arm 5 upward, hook members 6 and 7 engage with the left and right ends of the load arm.
An omnidirectional shape memory alloy member 8 made of Ni--Ti alloy having a tip thereof is located above the load arm 5, and its base is attached to the guide bar 14 by a fixing base 9. This shape memory alloy member 8 has electrodes 10 and 11 for heating with electricity, and has an oblong hole 12 in the center so that the current flowing between them branches into two paths. One of the branch parts 8a and 8b (branch part 8b in this embodiment) where the current branches into two paths has a notch 13 so that the current passage area is small and the surface area is large.

Next, automatic loading operation will be explained using FIGS. 2 to 4. FIG. 2 shows a side view of the automatic slider loading mechanism of the present invention. In the initial state, the slider 3 is pressed against the disk surface 1 by the elastic force acting below the load arm 5, and in this state, the hook member 6,
7 maintains a non-contact state with the load arm 5.
In the low-temperature phase below the transformation point, the shape memory alloy assumes a linear shape as shown by the solid line in the figure.
1, when heated above the transformation point, reverse transformation occurs,
Eventually, the head will rise due to recovery deformation to the previously memorized shape (dotted line in the figure). after that,
When the rotation of the disk is started and the required speed is reached, the current heating is stopped and the temperature of the shape memory plate becomes below the transformation point, and the slider smoothly descends and floats above the disk surface 1. The detailed movement of this slider 3 will be explained using FIGS. 3 and 4. FIG. 3 shows the current circuit passing through the shape memory alloy member 8. It is assumed that the current flowing is i, the currents passing through the branches 8a and 8b are i ₁ and i ₂ , and the respective resistances are R ₁ and R ₂ . Letting the amount of heat generated in both branch parts 8a and 8b be Q ₁ and Q ₂ , Q ₁ = i ₁ ²・R ₁ = i ²・R ₁・R ₂ / (R ₁ + R ₂ ) ² × R ₂ Q ₂ = i ₂ ² · R ₂ = i ² · R ₁ · R ₂ / (R ₁ + R ₂ ) ² × R ₁ . Since the branch part 8b has a notch and has a small cross-sectional area, R ₁ < R ₂ , that is, Q ₁ > Q ₂ , and assuming that the masses of both branch parts are approximately equal, the branch part 8 a has a smaller cross-sectional area. It rises earlier than the branch part 8b. On the other hand, when the current supply is stopped after both branch parts rise to the same temperature, the branch part 8b having a large surface area is cooled to a large extent, and transformation proceeds first. The movement of the head slider in response to this temperature change, viewed from the side of the slider, is shown in FIGS. 4a to 4f. The initial state of the disk 1 before rotation is a. If this grounded state is left for a long time or under a specific environment, adhesion will occur between the slider 3 and the surface of the disk. When electricity is applied in this state, the bridge girder 12
reaches the transformation point first, so a twisting force as shown in b can be applied to the slider. The adsorbed surfaces are separated from each other by such torsional force rather than the acting force perpendicular to the surfaces. It can be separated with very little force and without damage. As time passes, the temperature of the branched portion 8b also rises and reaches the transformation point, so both the branched portions 8a and 8b are displaced to their original memorized shape from c to d. Next, disk rotation is started while maintaining this state. When it is detected that the predetermined rotational speed has been reached and the energization is stopped, the branch part 8
Since the slider b is cooled first, the slider 3 descends in a posture that is susceptible to buoyancy as shown in e, and when it finally maintains a predetermined flying height, the hook member 6 and the 7 is out of contact with the load arm 5. To stop the rotation of disk 1,
The order of operations explained above is completely reversed, from f to a. In the above embodiment, the front of the slider is always raised not only during heating but also during cooling, which has the effect of providing stable automatic loading.

As another example, by connecting an insulating member with a large heat capacity to one of the branch parts, it is possible to differentiate the temperature rise.

In yet another embodiment, the temperature can be controlled by applying a magnetic field change from the outside and arbitrarily controlling the current flowing through one of the branch parts by the electromagnetic induction.

As yet another example, a dissimilar metal having a Peltier effect can be placed on one side of the branch to utilize the effect of endothermic or exothermic effects.

〔Effect of the invention〕

As described above, according to the present invention, complex sequence operations with multiple degrees of freedom can be performed with simple energization by utilizing the difference in time at which transformation starts in a shape memory alloy based on the energization heating method that causes a difference in heat generation distribution. This can be done with just a few operations. Therefore, it is possible to peel off the slider adsorbed to the disk surface by applying twisting force, which has the effect of not destroying the slider or gimbal portion.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an embodiment of an automatic loading mechanism for a slider according to the present invention, FIG. 2 is a side view of FIG. 1, and FIG. 3 is an embodiment of the present invention shown in FIGS. 1 and 2. FIGS. 4a to 4f are side views illustrating changes in the slider posture during automatic loading in the embodiment of the present invention shown in FIGS. 1 to 3. FIGS. DESCRIPTION OF SYMBOLS 1...Disk, 2...Magnetic head, 3...Slider, 4...Gimbal part, 5...Load arm, 6...Hook member, 7...Hook member, 8...Shape memory alloy member, 9...
Fixed base, 10...electrode, 11...electrode, 14...guide bar.

Claims (1)

[Claims] 1. An automatic loading mechanism for a slider comprising a slider with a head attached thereto, a pressing member that fixes the slider to its tip and applies a pressing force onto the disk surface, and a loading means facing the pressing member, wherein the loading means A shape memory alloy member exhibiting a shape memory effect based on thermoelastic martensitic phase transformation is used as a driving element, and a joule heating effect due to self-energization is used as a heating method for the shape memory joint member, and the difference in current density is An automatic slider loading mechanism is characterized in that it is possible to arbitrarily create a change in shape in an intermediate process between the start and end of phase transformation by creating a difference in heat generation distribution.