JPS5885970A - Magnetic head assembly - Google Patents

Abstract

PURPOSE:To detect a fault in a magnetic head easily and to perform the assured maintenance in order to increase the reliability, by forming a thin film distortion gauge by vapor-depositing an insulated layer, resistance layer, electrode layer and a protecting layer respectively at the gimbal part of a CSS (constant start- stop) type magnetic head. CONSTITUTION:A gimbal 3 bites and holds the sliders 2 which hold a magnetic head core 8 forming a magnetic gap between them. The thin films of the insulated, electric resistance, electrode and protecting layers are laminated at a part of a spring region 9 of the gimbal 3 by a thin film processing technique. Thus a thin film distortion gauge 10 is obtained. Then an abnormal displacement of the gimbal 3 is detected with the output of the gauge 10 given from the lead wires 11a and 11b. The electric resistance layer uses a Cu-Ni alloy, Cr-Ni-Mo alloy, etc., for example, which have a large gauge coefficient and a small temperature coefficient. Thus the cleaning and repairs are carried out after detecting the degree of impact, the frequency of impact, etc. Thus, the reliability of a magnetic head assembly is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to a floating magnetic head assembly, and more particularly to the structure of a means for detecting abnormal head vibration in the magnetic head φ assembly.

(2) Background of the technology In magnetic disk drives, since the surface runout of the magnetic disk, which is a recording medium, is large, this surface runout is closely tracked to accurately read and write information. A floating magnetic head is used for this purpose.

A floating magnetic head is normally started and stopped with the slider placed on and in contact with the disk surface (088-c).
Also, the flying height of the slider is usually 0.2 to 0.5, by balancing the precious spring that presses the slider and the air film spring generated from the air flow accompanying the rotation of the disk. The recording density is improved by setting the height to an extremely small height on the order of [μ inertia]. Therefore, in order to establish high-density recording technology, it is necessary to
It is important to develop a combination of a head and a disk with high performance, and to improve the stability and reliability of the head under the above-mentioned low flying conditions. In order to do this, it is extremely important to detect and deal with abnormal head vibrations at an early stage due to the adsorption phenomenon of the slider during startup, which occurs due to the smooth disk surface, or due to minute protrusions on the disk surface formed by dust, etc. is important.

(3) Prior art and problems A typical floating head assembly for a magnetic disk has a shape as shown in FIG. Slider 2. Gimbal 3. Cam 'Horok 4° arm 5, 9R load spring 6. The mounting is made up of a stand 7 and the like.

To detect abnormal vibrations of the head in the floating magnetic helad assembly, an acoustic emissive sensor, which is conventionally used for detecting distortion of rigid bodies, etc. is used.
(miss/ion) elements and sheet-shaped strain gauges were mainly used. However, in the above-mentioned AE element, since the detection is performed using bulk piezo vibration, it is difficult to miniaturize the element. Therefore, when in use, it must be mounted on the arm (Fig. 1, 5). Furthermore, when a foot-shaped strain gauge is mounted on a gimbal, the load applied to the gimbal is large, which affects the flying stability of the head, so it must be mounted on an arm as described above. In this way, conventional detection means have poor detection sensitivity because they indirectly detect the vibrations of the magnetic head and gimbal system, and they do not necessarily detect the vibrations of the magnetic head and gimbal system.
The problem was that it lacked reliability because it did not necessarily capture only the vibrations of the gimbal system.

(4) Purpose of the invention The present invention addresses the above-mentioned problems and provides means for sensitively and reliably detecting abnormal vibrations of the head caused by adsorption of the head or shocks given by protrusions on the disk surface. An object of the present invention is to provide a floating magnetic head assembly having the following features.

(5) Structure of the Invention The present invention provides a magnetic head assembly having a floating structure, in which an insulating layer, an electrical resistance layer,
4) It consists of an electrode layer and a protective layer, and is equipped with a thin film strain gauge that has the function of detecting the deformation of the gimbal when the head is floating. be a sign.

(6) Embodiments of the Invention The present invention will be described below using a plan view of main parts in one embodiment shown in FIG. 2 and a plan view of a thin film strain gauge in an embodiment shown in FIG. This will be explained in detail.

For example, as shown in FIG. 2, the floating magnetic head assembly of the present invention employs a thin film process technology on the spring region 9 of the jaw 3 that holds the slider 2 holding the magnetic head core 8 between the legs. A thin film strain gauge 10 consisting of an insulating layer, an electrical resistance layer, an electrode layer, and a retention layer is formed using a mechanical force.The thin film strain gauge 10 during operation is
The change in resistance value of the electrical resistance layer is the lead l1l11.11b
is detected by a bridge circuit (not shown) or the like.

Note that 12 in the figure indicates a magnetic head gap.

The thin film strain gauge described above has a structure as shown in FIG. 3, for example. That is, the lowest layer on the spring region 9 of the gimbal 3 in which the strain gauge is in direct contact is made of aluminum dioxide t=
It consists of an insulating layer 13 with a thickness of about 1 μm, typically made of Az, O, or the like. The insulating layer is formed through sputtering and lithography techniques. A plurality of electrical resistance layers 14 are laminated on the insulation layer 13 along the longitudinal direction of the spring region 9 of the gimbal 3 in a meandering manner. The electrical resistance layer 14 is formed using sputtering technology and lithography technology, and is made of a material with a large gauge coefficient (ratio of resistance change rate to length change rate).
In addition, it is desirable to use a material with a small temperature coefficient of resistance, such as a steel (Ou)/=Niracle Ni) alloy represented by Adopyx (58%0u742j6Ni), or a chromium (Ni) alloy.
Or)/Nickel (Ni>/Molybdenum (Mo) alloy, Ni10r alloy is used to form a thickness of about 1 [voice] and a line width of about 10 to 100 [μ].Then, the electrical resistance layer 14, there is an electrode layer i for connecting 1 m of leads (not shown) made of gold (Au) or the like.
sa and isb are provided. The electrode layer 151.15
The layer b is formed using sputtering, vapor deposition, and lithography, and has a thickness on the order of 1Cμ.

Furthermore, a protective layer 16 made of silicon dioxide (StO, etc.) is formed on the region where the electrical resistance layer 14 is formed using sputtering technology. In a thin film strain gauge having such a structure, the amount of deformation and the resistance change of the electrical resistance layer 14 exhibit a core relationship, and the gauge coefficient is approximately 2 [
%]. Also, the strain gauge is laminated directly onto the gimbal as described above. Therefore, the Mukuro strain gauge detects only the deformation of the gimbal 3 caused by the impact applied to the head section (magnetic head core 8 and slider 2) in the magnetic head assembly shown in FIG. Since the deformation of the gimbal 3 is directly transmitted to the strain gauge, detection sensitivity and reliability are high. Further, the strain gauge has an extremely thin film structure as described above. Therefore, the weight is extremely small, and at the same time, it does not significantly change the springiness of the gimbal 3, so it does not adversely affect the stability of head flight.In the above embodiments, Although an alloy layer is used for the electrical resistance layer of the thin film strain gauge, the sensitivity of the thin film strain gauge can be further increased by using a semiconductor layer with an extremely large gauge coefficient for the skeleton electrical resistance layer. However, in the case of a semiconductor layer, since the temperature coefficient of resistance is large, it is necessary to correct this point.

(7) As described in detail, according to the present invention, the impact applied to the bed when the magnetic head is floating can be detected with high sensitivity and reliability.

Therefore, by cleaning and repairing the magnetic disk surface and magnetic head according to the magnitude and frequency of impact, the C8S resistance of magnetic disk devices that perform high-density recording and reading can be greatly improved, and data Improved reliability.

[Brief explanation of the drawing]

FIG. 1 is a plan view of the main surface of an ordinary floating magnetic head assembly for magnetic disks, FIG. 2 is a plan view of the main part of an embodiment of the present invention, and FIG. FIG. 2 is a plan view of a thin film strain gauge in one embodiment. In the figure, l is a magnetic head, 2 is a slider, 3 is a gimbal, 4 is a cam follower, 5 is an arm, 6 is a precious spring, 7 is a mounting base, 8 is a magnetic head core, 9 is a spring area, 10
1 is a thin film strain gauge, lla and llb are lead wires, 12 is a magnetic head gap, 13 is an insulating layer, 14 is an electrical resistance layer, 15a and tsb are electrode layers, and 16 is a film holding layer. Akira im Akira 3 Figure tb14:)

Claims (1)

[Claims] In a magnetic helad e assembly with a floating structure, an insulating layer, an electrical resistance layer, an electrode layer, and a protective layer are formed directly on the gimbal (support spring) that supports the magnetic head using thin film process technology. 1. A magnetic head assembly comprising: a thin film strain gauge having a function of detecting deformation of a gimbal when the head is floating.