JPS61178786A - Floating head for magnetic disk - Google Patents

Abstract

PURPOSE:To detect the presence or absence of contact between the head and the disk with high sensivity by preparing the head slider part from piezoelectric material, forming electrodes on opposing end faces respectively, and making it possible to use the slider as impact sensor. CONSTITUTION:The slider part 8 is formed of crystals of piezoelectric material such as lithium niobate or lithium tantalate, or piezoelectric ceramics such as lead zircontitanate or lead titanate. The electrodes 20 are formed on opposing end faces of the slider part 18 respectively. The electrode forming surfaces are formed on the radial opposing end faces of the disk as shown with slant lives. Since the slider part 18 itself is constituted of the piezoelectric composition, electric charges are produced by impact or vibrations produced upon contact between the disk and the head, thus producing electric signals between the electrodes. The presence or absence of the contact can be detected by detecting these signals.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a floating head in a magnetic disk recording device that is capable of detecting the presence or absence of contact between a disk and a head, and more specifically, the present invention relates to a floating head in which the presence or absence of contact between a disk and a head can be detected. This invention relates to a floating head for a magnetic disk that is configured to function as an impact detection sensor.

[Prior Art] A floating magnetic head of a magnetic disk device is usually attached to the tip of a rad arm via a support spring, and is composed of a magnetic head body for reading and writing data, and a slider portion to which the head body is attached. During normal operation, the slider section floats slightly (usually on the order of a few tenths of a micrometer) due to the pressure caused by the air flow generated by the rotation of the disk. If the disk and magnetic head come into contact at this point, the recorded content may be destroyed (called a "head crash"), and other problems may occur. Therefore, a polishing head called a burnish head made of hard material is A pseudo head is used to fly over the surface of the disk to be processed with a flying height smaller than that of an actual floating magnetic head, the protrusions are removed, and the contact points are polished so that all the contact points are smooth. It is necessary to confirm that this does not occur.

In the conventional technology, in order to detect the presence or absence of contact between the disk and the floating head, an AE sensor is attached to the head arm and the head and disk are connected to each other.
．． V→Kurachiba (→Go 1. It is detected by the acoustic signal transmitted through the acoustic propagation path via the sweet arm.

[Problems to be Solved by the Invention] However, in such a configuration, the acoustic waves generated by the impact at the time of contact propagate through several components and reach the AE sensor, so the acoustic propagation path is long and When tightening screws, there is severe attenuation at contact points such as parts and adhesives, which has the major disadvantage of deteriorating the S/N ratio and poor detection performance.

Also, since small AE sensors are extremely expensive,
The AE sensor is attached to the head arm during inspection, but it is removed after the inspection is completed, and the disk storage container, which has been kept dust-free, has to be opened and closed each time, increasing the chances of introducing dust. This is a major cause of head-disk contact accidents.

In order to improve the sensitivity of impact detection, it is possible to attach a piezoelectric chip directly to the floating head, but such a configuration will affect the flying characteristics, reducing the flying height and causing unstable operation. It cannot be implemented because it occurs.

The purpose of the present invention is to eliminate the above-mentioned drawbacks of the conventional technology, to detect the presence or absence of contact between a head and a disk with high sensitivity, and to make the sensor inexpensive, so that it is possible to remove the sensor each time an inspection is performed. An object of the present invention is to provide an improved floating head for a magnetic disk that does not require work such as attaching or removing.

[Means for Solving the Problems] The present invention, which can achieve the above-mentioned objects, comprises making the slider part of the head from a piezoelectric material, forming electrodes on the opposing end faces thereof, and This is a floating head for a magnetic disk having a configuration in which the slider portion can be used as an impact detection sensor.

The floating head in the present invention includes a floating magnetic head that actually reads and writes information, as well as a punisher for polishing a disk.
It also includes a head dedicated to inspecting the surface condition of the head and disk surface.

Piezoelectric crystals and piezoelectric ceramics are used as the piezoelectric material constituting the slider section. The end surfaces forming the electrodes are, for example, two surfaces facing each other in the radial direction of the disk, and leads are drawn out from these electrodes and passed through the support spring and the head arm to the outside.

Note that in the present invention, the "slider section" refers to a member other than the magnetic head main body made of a magnetic material in the case of a normal magnetic head.

[The working head is slightly floating due to the pressure caused by the air flow generated when the disk rotates. When the head and the disk come into contact, an electric charge is generated due to the shock vibration generated at the time of contact, and a voltage is induced between the two electrodes, so that it is possible to detect whether there is a contact or not. Since the slider section itself operates as an impact detection sensor, there is no acoustic propagation system and the impact is directly sensed, resulting in extremely high sensitivity.

And since there is no need to separately attach a piezoelectric chip,
[Embodiment] The present invention will be described in more detail below with reference to the drawings. FIG. 1 is an explanatory diagram showing an example of the mounting structure of a floating magnetic head for a magnetic disk. The floating magnetic head 10 is
It is attached via a support spring 14 to the tip of a helad arm 12 that can be swung horizontally by a voice coil or the like, and floats by a few tenths of a micrometer due to the pressure of the air flow generated by the rotation of a disk (not shown). .

An example of the floating magnetic head 10 is shown in FIG.

The floating magnetic head shown in this embodiment is an example of a positive pressure composite type. The magnetic head main body 16 for reading and writing information is embedded in the slider section 18 in order to effectively receive the laminar flow of air above the disk. The slider section 18 has a disk facing surface (top surface in FIG. 2).
It has a unique shape with grooves to receive the upward force from the airflow.

These are the material of the slider section 18 and its structure.

In other words, in the present invention, the slider section 18 is made of a piezoelectric crystal such as lithium niobate or lithium tantalate, or a piezoelectric ceramic such as lead zirconate titanate or lead titanate, and electrodes are provided on opposing end surfaces of the slider section 18, respectively. 20 is formed. Regarding the surface on which electrodes are to be formed, it is difficult to attach electrodes to the end surface that protrudes opposite to the disk, and the magnetic head main body 16 is attached in the circumferential direction of the disk, which is not very preferable. Therefore, in this embodiment, as indicated by diagonal lines in FIG. 2, the grooves are formed on opposite end surfaces of the disk in the radial direction. Each electrode 2
Leads (not shown) are pulled out from each of the leads (not shown), and are pulled out through the support spring 14 and the head arm 12.

As the electrode forming surface, in addition to the positions shown in the above embodiments, the groove and back surface of the disk facing surface, the side surface of a protrusion formed on the disk facing surface, etc. may be used.

When such a floating magnetic head 10 is used, since the slider section 18 itself is made of a piezoelectric composition, the shock and vibration that occur when the head and disk come into contact generate a corresponding charge, and both electrodes Since an electrical signal is generated between the two, it is possible to detect the presence or absence of contact by detecting it. Therefore, it is functionally the same as the conventional AE sensor. In the present invention, the slider section 18 itself that receives an impact acts as an impact detection sensor, and there is no need for a long and complicated acoustic propagation system as in the prior art. Since it is directly sensed, it has extremely high sensitivity, and since the slider section 18 may have the same shape as the conventional one, there is no adverse effect on the flying characteristics during use.

The above description has been made using an ordinary floating magnetic head that reads and writes data as an example, but the present invention applies not only to such floating heads but also to vanish heads, inspection heads,
It goes without saying that this can also be applied to NM heads and the like. In the case of a burnish head, most of the slider portion may be made of a piezoelectric material, the surface facing the disk may be covered with a hard material, and the electrode surface may be formed in the same manner.

[Effects of the Invention] As described above, the present invention is a floating head in which the slider part is made of a piezoelectric material, and electrodes are formed on the opposite end surfaces of the slider part so that the leads can be pulled out. It functions as a shock detection sensor, and has extremely high sensitivity because it can directly convert the shock it senses into an electrical signal. Since the head functions as a sensor, it can be made to have exactly the same shape as a conventional head, and there is no risk of adversely affecting the flying characteristics during operation.

In addition, the slider part is a relatively large part, and unlike the ultra-small AE sensor that was conventionally attached to the rad arm separately, it can be manufactured at low cost and can be incorporated as a component of the magnetic head device, so it can be assembled once assembled. Once removed, there is no need to take it out, and the inside of the disk device storage container can be made dust-free, greatly improving the reliability of the device.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an example of the mounting structure of a floating magnetic head for a magnetic disk, and FIG. 2 is an explanatory diagram showing an embodiment of the floating magnetic head for a magnetic disk according to the present invention. 10...Floating magnetic head, 12...Head arm,
14... Support spring, 16... Magnetic head body, 18
...Slider part, 20...electrode.

Claims (1)

[Claims] 1. A floating head for a magnetic disk, characterized in that the slider part of the head is made of a piezoelectric material, and electrodes are formed on opposing end faces of the slider part, so that the slider part can be used as an impact detection sensor.