JPS6243880A - Dynamic characteristic inspecting device for magnetic head support system - Google Patents

Abstract

PURPOSE:To attain stable, simple and proper inspection up to a high frequency region of the dynamic characteristic of a magnetic head support system by using a high speed flow a reduced flow nozzle as the vibrating method. CONSTITUTION:A head assembly 6 consists of a magnetic head 1, a slider 2, a gimbal 3 and a support spring 4. The high speed flow from the nozzle 9 is set so as to contact the support spring 4 at a right angle. The head assembly 6 is fitted to a support base 5, a disc 7 is rotated to float the slider 2 on the disc 7, interference fringe is observed by using a light source 22, a half mirror 20 and a camera 21 so as to confirm that the slider 2 is in the normal floating state. A blower is started and a flow speed at the outlet of the nozzle 9 is adjusted to a desired flow speed, the movement of the slider 2 is observed in a form of floating quantity fluctuation by using the half mirror 20, the camera 21, the light source 22 and a processing device 23 so as to obtain the dynamic characteristic.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an inspection device for inspecting the dynamic characteristics of a magnetic head support system in a magnetic disk device, and in particular to an inspection device for inspecting the dynamic characteristics of a support system having a support spring with a relatively high natural frequency. The present invention relates to an inspection device suitable for inspecting characteristics.

[Background of the invention]

As a conventional device for inspecting the characteristics of a magnetic head support system, for example, "Image scanning method magnetic disk slider submicron levitation measurement" in Proceedings of the Japan Society of Mechanical Engineers, A33O-14, pp. 138-140, published on July 25, 1980. There is something disclosed in "Development of Equipment". This measuring device is
The objective is to measure the static characteristics of the gap between the slider and disk that supports the magnetic head, in other words, the time average value of the gap, and a means to actively vibrate the support system is not provided. Not yet. In addition, Transaction of CI, published in January 1982, Engineering 8. Engineering, E Journal of Replication Chikunoroshii (Tran
actions of the ASMEJourn
al of publication technology
Visible Laser Interferometer Fore-Air Bearing Separation Measurement to Submicron Accuracy (AVisibl) disclosed in Vol.
e 1aser interferometer fo
r AirBearing 5 separation M
easurement t.

Submlcron Accuracy) shows an example of measuring the change in gap over time. In this case as well, no active means of remediation is provided.

In the head support system used in the same document, the main frequencies of temporal changes in the gap are 200°, 340°, and 580°.
Since the frequency is relatively low in z, etc., the amplitude is relatively large, and the dynamic characteristics of the support system can be measured even without providing any active vibration excitation means. However, recent advances in head support systems have increased the main frequency to about 2 kHz, and normally the i
- stabilized at t. Therefore, it is necessary to provide active vibration excitation means to check for abnormalities in dynamic characteristics.

[Purpose of the invention]

An object of the present invention is to provide a dynamic characteristic of a magnetic head support system that is equipped with an excitation means capable of stable excitation up to a high frequency range and a dynamic characteristic measurement means capable of accurately evaluating the dynamic characteristics of the support system. The purpose is to install inspection equipment.

[Summary of the invention]

The purpose of dynamic characteristic testing of support systems is to detect variations between products and to select products with abnormalities in amplitude and frequency. Therefore, the frequency characteristics of the amplitude of the excitation force must be stable and do not change each time a product is inspected. On the other hand, the frequency characteristics of the excitation force do not need to have a uniform amplitude distribution. We have tried conventional methods of excitation that meet this condition, such as using a moving coil type exciter or a piezo element.
In both cases, in the frequency range higher than about 100 to 1 kHz, resonance appears in the structural system in which the excitation system and the support spring that is the object to be inspected are integrated, and it is clear that stable loading cannot be achieved. Became.

Therefore, it is important to note that the support spring vibrates relatively easily due to the wind, that the frequency characteristics of the wind speed uniformly decrease in the region of about 100 Hz or more, and that the Focusing on the fact that vibration can be caused by contact, we tried an excitation method that placed a support spring in a high-speed flow, and found that the frequency characteristics of the excitation force had no specific peaks up to the high frequency region, and the excitation was stable. It turns out that is possible.

On the other hand, the following can be said about the measurable quantities that can be used to evaluate dynamic characteristics. In other words, the purpose of evaluating the dynamic characteristics of the support system is to keep the influence of the dynamic characteristics of the support system on the flying height of the head below a certain level. Therefore, in the present invention, it was decided to use the frequency characteristics of flying height fluctuations as an evaluation quantity. Flying height fluctuations can be measured using optical interferometry, reading a magnetic signal written on a disk and calculating the flying height fluctuation from changes in the output voltage, or detecting the capacitance between the head and disk. Known methods such as the following can be used.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. In FIG. 1, 1 is a magnetic head, 2 is a slider, 3 is a gimbal, and 4 is a support spring. These k constitute a head assembly 6.

5 is a support stand. 7 is a transparent disk that rotates in the direction of arrow A, and an air film is formed between it and the slider 2;
floats above the disk with a minute gap. An 8-piece windbreak enclosure prevents the influence of the flow caused by the simultaneous rotation of the disc 7. Reference numeral 9 denotes a nozzle, which is set so that the high-speed flow from the nozzle hits the support spring 4 at right angles. FIG. 2 shows details of the configuration of the nozzle 9. The nozzle 9 has a run-up part 10, a contraction part 11, and a parallel outflow part 1.
Consists of 2. A pressure gauge 13 is attached to the run-up section 10. Further upstream, a turbulence plate 14, a main valve 15, a bypass pipe 16, a bypass valve 17, a tank 18, and a blower 19 are provided. Next, returning to FIG. 1 again, a half mirror 20 and a camera 21 are provided on the opposite side of the disk 7 from the slider 2, and the light from the light source 22 is used to create a gap between the slider 2 and the disk 7. The camera 21 detects the movement of interference fringes that occur in
The movement of the interference fringes is converted into an electric signal by the image processing device 23, and the movement of the interference fringes is converted into the movement of the flying height of the slider 2, and the frequency can be analyzed.

When inspecting the dynamic characteristics of a magnetic head support system using this device, the head assembly 6 is mounted on the support stand 5, and the slider 2 is floated above the disk 7 by rotating the disk 7. let Then, the interference fringes are observed using the light source 22, the vine mirror 20, and the camera 21, and it is confirmed that the slider 2 is in a normal floating state. Next, the blower 19 is started and the main valve 15 and bypass valve 17 are adjusted so that the pressure indicated by the pressure gauge 13 becomes a predetermined pressure. The predetermined pressure is a pressure determined in advance so that the flow velocity at the nozzle outlet becomes a desired flow velocity. Next, the movement of the slider is observed in the form of flying height fluctuation using the half mirror 20, camera 21, light source 22, and processing device 23 to obtain its dynamic characteristics. Then, it is determined whether the obtained dynamic characteristics are within a predetermined range or not, and abnormal heads are selected.

When this is completed, replace it with the next head assembly 6 and repeat the same operation, but from the second time onwards, if the reading on the pressure gauge (3) does not change, the main valve 15 and bypass valve 16 will not be adjusted. At the stage of confirming that the slider 2 of the test object is floating normally, the shield plate (
(not shown) to prevent the flow from hitting the object to be inspected.

In this example, a high-speed flow from the contracted flow nozzle 9 was used as the vibration excitation method, so as far as we observed, stable excitation is possible up to a high frequency range of 20 kHz, and it is possible to misjudge the quality of the dynamic characteristics of the magnetic head support system. There is an effect that can be determined without any problems.

In addition, the slider 2 is floated, and the slider 2 and the disk 7 are
Since the gap between the magnetic head and the magnetic head is measured, it is possible to evaluate changes in the flying height, which is the purpose of testing the dynamic characteristics of the magnetic head support.

In this embodiment, the flow from the contraction nozzle 9 was used, but it is also possible to use the suction flow to the nozzle 9. In short, if a high-speed flow is used, almost the same effect can be obtained.

Furthermore, in this embodiment, since the flying height is measured in a pattern using an optical method, there is an effect that changes in the attitude of the slider 2 can also be observed. However, for example, there is a method in which a magnetic signal written in advance on the disk 7 is read by a magnetic head and the flying height fluctuation is calculated from the amplitude fluctuation of the read signal, or a flying height fluctuation is calculated from the change in the electric capacitance between the slider 2 and the disc 7. It is also possible to use a calculation method.

Next, a second embodiment is shown in FIG. Although the differences from FIG. 1 are mainly shown, the tip of the support spring 4 is connected to the pivot 24.
It is supported by This method is economical because the abnormal support spring can be removed at an early stage of the head assembly assembly process.

Next, a third embodiment is shown in FIG. In this embodiment, the assembly of the support spring 4 and the gimbal 3 is the object to be inspected, and the gimbal pivot 25 is supported by the pivot 24. This embodiment also has the same effect as the second embodiment.

〔Effect of the invention〕

According to the present invention, the dynamic characteristics of a magnetic head support system can be tested stably, simply, and accurately up to a high frequency range.

[Brief explanation of drawings]

FIG. 1 is a perspective view illustrating the overall configuration of an embodiment of the present invention, FIG. 2 is a perspective view showing details of the nozzle in FIG. 1,
3 and 4 are perspective views showing a method of supporting a support spring in another embodiment of the present invention. DESCRIPTION OF SYMBOLS 1...Magnetic head, 2...Slider, 3...Gimbal, 4''...Support spring, 5...Support stand, 6...
Head assembly, 7... Disc, 8... Windbreak enclosure,
9... Nozzle, 10... Run-up section, 11... Contraction section, 12... Parallel outflow section, 13... Pressure gauge, 14...
・Turbulence plate, 15...Main valve, 1θ...Bypass pipe, 1
7... Bypass valve, 18... Tank, 19... Blower, 20... Half mirror 121... Turtle 2.2
2°゛4ゝ・23°°°0”4ゝ1・“°°°°°1冨 1 Figure 2 Figure y 3 Figure

Claims (1)

[Scope of Claims] 1. In an inspection device for testing the dynamic characteristics of a magnetic head support system by vibrating the support system, a high-speed flow generating means as a means for vibrating the support system is used to test the dynamic characteristics of the support system. 1. A dynamic characteristic testing device for a magnetic head support system, comprising: measuring means. 2. A dynamic characteristic testing device for a magnetic head support system as set forth in claim 1, characterized in that a contracted flow nozzle is used as a means for generating a high-speed flow. 3. An apparatus for testing dynamic characteristics of a magnetic head support system as set forth in claim 1, further comprising means for measuring a gap between a slider and a disc as a means for measuring dynamic characteristics of the support system.