JPS5888873A - Magnetic head and its production - Google Patents

Abstract

PURPOSE:To obtain a load spring having extremely high reliability in a simple way, by trimming the width of a plate spring with the electric signal control and by a laser trimming process, etc. while checking the load of the plate spring of a floating magnetic head. CONSTITUTION:A slider 6 is attached at the tip of a gimbal spring 2, and a bending process is applied to the part 3 shown by oblique lines. Such spring 2 is attached in parallel to a head arm 1. Thus the spring force generated at the part 3 is transmitted to a pad 7 through a load beam 5 and the slider 6 and then converted into the electric signal. This electric signal is fed to a control box 8 and compared with the reference signal. A minute hole 10 is drilled at the part 3 by means of a laser trimming device 9 to reduce the spring load. This drilling is repeated until the load signal becomes equal to the reference voltage and while checking the spring load. These operations are carried out quickly and with high precision without using any man power nor lowering the spring force. Thus a load spring having high reliability is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a floating W magnetic head used in a magnetic disk device, which is an external storage device of an electronic computer, and a manufacturing method capable of accurately controlling the spring load of the magnetic head.

In recent years, electronic computers have diversified their functions and handled an increase in the amount of data they handle, and there is a demand for smaller external storage devices and larger capacities. Under these circumstances, magnetic disk drives using floating heads are preferred as low-cost, large-capacity storage devices.

%, the floating head of a magnetic disk drive is a floating ship (hereinafter referred to as a slider) containing an electromagnetic transducer that floats over a magnetic disk medium running at high speed while maintaining a slight distance (0.5 to 1ξ chron). However, in order to always keep the same lft stable, the dimensional accuracy of the flying surface of the slider and the load applied to the slider must be precisely controlled.

By the way, the load applied to such a floating head is given by a metal plate spring, and the design is such that the variation in load is usually less than ±10% to achieve stable floating of the head. There are many hills. For example, in a Winchester type magnetic head, which is one of the conventional heads, the load applied to the slider of the head is about 109 mm, and at this time, the load between it and the medium traveling at a speed of 37 m/m is about 0.9 mm.
5μm! The situation is maintained. When the load changes by about 1y, the 0.5 μm gap changes by about 0.03 μm, but this amount is considered to be an allowable limit in terms of signal O write/read characteristics.

Although the spring load applied to the head has a serious effect on the characteristics of the head, in reality it is extremely difficult to control the load IQ. This is based on the well-known principle that the bending force of a plate spring is proportional to the cube of the plate thickness and Young's modulus. tb Winchester cutting heads like the one in the row above use a stainless steel plate with a thickness of 50 microns as the spring material.In order to keep the rounding spring force within ±10% of the plate thickness, it is necessary to Since only a tolerance of 3.2% is allowed, in the case of a 50 μm plate, the tolerance is ±1.6 μm. However, in actual manufacture of stainless steel plates, the plate thickness tolerance is ±3 to ±5μ.
m and ±1.6 μm is a completely unrealistic cage. Furthermore, in addition to the plate thickness tolerance, the Young's modulus of the plate also changes depending on the material loft and the processing conditions of low-temperature annealing after main processing for the same material, so in reality, the load value is controlled by controlling the plate thickness and Young's modulus tolerance. It has become impossible.

In order to deal with this situation, conventional heads obtain the desired load by adjusting the bending angle of the leaf spring. In other words, regardless of the spring plate thickness or Young's modulus, all springs are bent so that a large load is generated for the purpose, and while checking the load, each spring is over-bent and corrected to relieve it. It really requires a complicated process.

This method also. Since the spring force is partially yielded, this method is unfavorable from the viewpoint of spring load and long-term reliability.

The object of the present invention is to eliminate the drawbacks of the conventional head manufacturing method as described above, and to provide a magnetic head with four load springs that is accurate and highly reliable, and a method for manufacturing the same. .

This object of the present invention can be achieved by introducing a method of trimming the width of the head leaf spring by electrical signal control while checking the load of the head leaf spring.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a magnetic head according to an embodiment of the invention.

In FIG. 1, a gimbal spring 2 having a slider 6 at the tip of a head arm 1 is attached. This gimbal spring 2 has a diagonally shaded portion 3 which is bent and has a tongue portion 4 of the gimbal spring. This tongue part 4 is lower low bar 5 and ff! are connected directly. Note that the tongue portion 4 is considered to be a rigid body. Since the gimbal spring 2 is kept parallel to the arm 1, the spring force generated by the bending portion 3 is transmitted to the slider 6 through the load beam 5, and a load is applied thereto. The spring force is applied to the small hole 7 in the bending part 3 of the gimbal.
The width of the bent portion is effectively reduced by opening the width of the bent portion.

This situation can be implemented using the method shown in Figure @2.

In FIG. 2, the arm 1 is fixed, and the slider 6 is pushed by the pad 7 so that the slider 6 is in the same posture as when it runs on the magnetic medium. In other words, the spring force is applied to the pad 7 through the load arm 5 and slider 6.
It is reported that. The force applied to pad 7 is converted into an electrical signal and sent to control box 8, where it is compared with a reference signal voltage. Since the load is manufactured in advance to be larger than the set target value, the electrical signal of the load is significantly higher than the reference voltage, and this causes the laser illing device to operate, causing the curved portion 3 of the spring 2 to Drill a small hole. By making the hole, the effective width of the curved portion 3 is reduced and the load is reduced. This load is transmitted to the control box through pad 7 and compared with the reference voltage again.
If the load is still not as large as the reference voltage, the laser spot moves and makes another minute hole. When this operation is reversed and the spring load becomes equal to the target cage, that is, when the load signal becomes equal to the reference voltage, the laser
The illing device stops working.

All operations during this time are performed electrically and mechanically.

This is done in a very short time without any human intervention.

High reliability and long-term use can be achieved because the spring force that has increased does not yield.As mentioned above, it is easy to gradually reduce the width of the p-plate spring by controlling the electrical signal while checking the load on the head. It is possible to accurately obtain the desired magnetic head load.

In the above example, laser milling was shown as a method of reducing the spring width, but if other methods are used, the same effect as described above can be obtained by pressing. It goes without saying that it is also possible to make through holes during laser milling, or to form grooves in the thickness direction of the leaf spring O.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a magnetic head manufactured by the manufacturing method of the present invention, and FIG. 2 is a diagram showing the construction method according to the present invention. DESCRIPTION OF SYMBOLS 1...Arm, 2...Gimbal spring, 3...Bending portion, 6...Slider, 7...Pad, 9... ...Laser milling equipment.

Claims (2)

[Claims] (1) A magnetic head characterized by including a plate that generates a load on the magnetic head, and a hole or groove formed in the inside of the plate spring or partially trimmed in thickness. (2) A method of manufacturing a magnetic head in which the load suitable for moths is obtained by partially trimming the width or thickness of the leaf spring that generates the load (by electrical signal control while checking the load on the magnetic head).