JP2585340B2 - Magnetic head gimbal assembly - Google Patents

Description

The present invention relates to a magnetic head gimbal assembly of a double-sided head type floppy disk, and relates to a magnetic gap of a magnetic head mounted on a gimbal spring (hereinafter abbreviated as a gimbal). The present invention relates to a structure having excellent positional accuracy.

[Conventional technology]

2. Description of the Related Art Conventionally, magnetic disk devices are well known as external storage devices such as word processors and personal computers. In recent years, in particular, floppy disk drives that are inexpensive, small, simple, and have compatibility between a recording medium and a drive have been widely used. .

A magnetic head used in this floppy disk drive has a magnetic head slider assembly (hereinafter referred to as a magnetic head assembly) in which both sides are held by sliders so that the magnetic gap stably contacts a floppy disk as a recording medium. After a magnetic coil and a back bar are incorporated into this magnetic head assembly, it is mounted on a gimbal together with a shield member and a wiring board to form a magnetic head gimbal assembly, and then in the radial direction of the floppy disk. It is used fixedly on a head carriage that moves to bring the magnetic gap to a predetermined track position.

Here, the accuracy of the gap depth, which is the depth dimension from the medium running surface of the magnetic gap of the magnetic head assembly to the magnetic coil storage space, is formed with high precision because it affects the electromagnetic conversion characteristics of the magnetic head. There must be.

When the magnetic head assembly is mounted on the gimbal for the purpose of maintaining the compatibility of the magnetic head gimbal assembly, a magnetic gap is formed with respect to a reference point on the gimbal that fixes the gimbal on the head carriage. Must be accurately positioned.

Hereinafter, the configuration of the related art will be described with reference to the drawings. Third
FIG. 4 is an assembly diagram of a conventional magnetic head assembly, FIG. 4 is a top view of the conventional magnetic head gimbal assembly, and FIG. 5 shows main parts of the conventional magnetic head gimbal assembly.
FIG. 6B is a side view, FIG. 6B is a rear view, and FIG. 6 is a schematic diagram of magnetic gap positioning for a conventional slider.

In FIG. 3, 34 is a magnetic head assembly, 4 is a front core formed of manganese zinc ferrite which is a magnetic material, and the front core 4 is a center core 4C and an outer core joined to both sides of the center core 4C. 4D, S is a medium running surface, and a recording / reproducing gap 4A is provided between the central core 4C facing the medium running surface S and each outer core 4D.
And an erasing gap 4B. Numeral 3 denotes a pair of sliders made of nonmagnetic ceramic such as barium titanate and calcium titanate, which are composed of a larger 3A and a smaller 3B which are sandwiched and joined from both sides of the front core 4. The medium running surface S of the slider 3 is formed on the same plane as the medium running surface of the front core 4. Reference numeral 6 denotes an electromagnetic coil, which is inserted into the core leg of each outer core 4D. Reference numeral 5 denotes a back bar formed of the same magnetic material as that of the front core, and is joined to a lower portion of each core leg of the front core 4 so as to close two magnetic paths passing through both magnetic gaps 4A and 4B. As shown in the figure, the front core 4 of the conventional magnetic head assembly is set so that the end face in the medium running direction is substantially the same as the slider end face in the same direction, and the back bar 5 The end face is set to be substantially flush with the outside cores 4D of the front core 4 and the outside of the front core 4D.

4 and 5, reference numeral 2 denotes a gimbal made of a stainless steel thin plate having a thickness of about 50 μm. The gimbal 2 has reference holes 2B, 2B for fixing to a head carriage.
Slits 2G and 2H are provided so that the magnetic gap can always follow the movement of the flexible recording medium stably, and an opening 2C is formed almost at the center thereof. Cantilever outer projecting pieces 2E, 2E, center projecting piece
2D is formed. Here, since the central projecting piece 2D has a cantilever shape, there is a risk that the central projecting piece 2D will be deformed when receiving a strong impact from the support point 2F of the pivot of the head carriage. Reference numeral 1 denotes a flexible wiring board, which is incorporated on the gimbal 2 opposite to the magnetic head assembly 34, and is connected to each terminal of the magnetic coils 6, 6.

Conventionally, after the sliders 3A and 3B are bonded to both side surfaces of the front core 4, the gap depth is set to a predetermined value by performing a process such as grinding, lapping, and polishing from the medium running surface S side, and a so-called depth forming process. Have been.
This depth setting step includes a slider 3A having mechanical strength,
Slider 3
As the relative positioning of the magnetic gap with respect to the lower end surfaces of A and 3B can be set more accurately, higher accuracy is realized.In general, this positioning is performed by using the lower end surfaces of the front core feet that can set the distance from the magnetic gap accurately. Performed as a reference.

In FIG. 6, reference numeral 8 denotes a jig used in the depth-providing step. Conventionally, this positioning is performed by a groove of a concave groove 8A set at a predetermined depth of the jig 8 as shown in FIG. Align the bottom end of the foot of the front core 4 which is the reference plane with the bottom,
The sliders 3A and 3B are placed on the bottom surface of the jig 8, and the pressure, the slider upper portions P1 and P2, the front core upper portion P3, and the slider side surfaces P4 and P5 are applied from each direction.

In general, the positioning of the magnetic gap when the magnetic head assembly is mounted on the gimbal 2 is performed by positioning the magnetic gap through the center of the gimbal reference holes 2B, 2B, and passing through the center of the Y axis and the center of the gimbal that coincides with the medium traveling direction. It is necessary to satisfy three factors: the distance from the magnetic gap to both X-axis axes at right angles, and the angle formed by the magnetic gap with respect to the Y-axis direction.
Then, the front core 4 and the back bar 5 are projected from the opening 2C of the gimbal 2 to the surface opposite to the medium side, and the magnetic head assembly 34 is mounted on the gimbal 2, and the projections 2E, 2E
The position of the magnetic gap in the X-axis direction and the angle with respect to the Y-axis are set by abutting each foot of the front core 4 on the tips of D and 2E. On the other hand, the positioning in the Y-axis direction is set based on the slider end face in the medium running direction or the side surface of the foot of the front core 4.

[Problems to be solved by the invention]

However, the conventional front core 4 and slider 3A,
Because the lower end of 3B is not aligned on the same plane, the above-described special positioning jig 8 is required in the depth-projecting step. Due to the method, it is difficult to finish the surface roughness, flatness, depth and the like of the groove bottom with high accuracy, and secondly, dust and dirt are formed on the groove bottom of the narrow slit which is difficult to clean.
There is a problem that the alignment accuracy is low because dirt, dust and the like are likely to remain, and the cost is high due to the use of an expensive fine grooving grindstone, troublesome grooving, groove cleaning, and the like. .

In addition, since the front core is generally thin, if it is brought into contact with the tip of the gimbal positioning protrusion with a strong force, the front core may break or partially break (especially at the corners).
In order to cause breakage, chipping, and the like, a gap is formed in the contact portion because the contact is performed with a weak force, which causes a positioning error of the magnetic gap.

As described above, in the conventional magnetic head gimbal assembly, since the positioning of the magnetic gap is insufficient, a positioning adjustment operation that requires a long time again when mounting the head on the head carriage is required. In a double-sided head type floppy disk drive, it is also necessary to match the relative positioning and angle relationship of the magnetic gaps of the two magnetic heads arranged vertically above and below the recording medium. It has the disadvantage of increasing the cost of the floppy disk drive. Further, since these operations are performed while observing a magnetic gap of several μm while enlarging it, a large number of expensive equipment is required, and there is a problem that the equipment is amortized and the cost is increased.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a magnetic head gimbal assembly which can solve the above-mentioned problems and can easily obtain the positional accuracy of a magnetic gap.

[Means for solving the problem]

In order to achieve the above object, the present invention has a structure in which an outer core is joined to both sides of a central core, and a recording / reproducing gap and an erasing gap are formed by facing the outer core and the medium running surface of the central core. An electromagnetic coil is disposed on each of the outer cores of the front core having a gap, and a back bar is held at a lower end portion of a foot of each core of the front core so as to close a magnetic path of the front core. A magnetic head gimbal assembly in which a magnetic head assembly having a configuration in which a slider is bonded to hold the front core is mounted on a gimbal such that the respective magnetic gaps are positioned at predetermined positions. The lower end of each of the outer cores is substantially flush with the lower end of the slider.

Further, the lower end of the central core is set shorter than the lower end of the outer core.

〔Example〕

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a view showing a magnetic head gimbal assembly according to one embodiment of the present invention, wherein (a) is a top view, (b) is a bottom view,
(C) is an AA sectional view of (b), and (d) is BB
Sectional drawing, (e) is a CC sectional view. However, in FIG. 1 (b), the electromagnetic coil is omitted because the drawing becomes complicated. 2 (a) is a side view, FIG. 2 (b) is a bottom view, and FIG. 7 explains a depth setting process for the slider of the magnetic head gimbal assembly. In the drawings, (b) is a side view, and (a) is a cross-sectional view taken along line AA of (b).

Since the basic configuration of this magnetic head gimbal assembly is the same as that of the conventional magnetic head gimbal assembly, the same components are given the same numbers and names as those of the conventional magnetic head gimbal assembly, and description thereof is omitted. Only the configuration will be described.

First, as shown in FIGS. 1 (c), (d) and (e), the lower ends of the feet of the outer core 4D of the front core 4 are almost the same as the lower ends of the sliders 3A and 3B (about +5 to -10 μm). The lower end of the foot of the central core 4C is set shorter by about 50 to 200 μm.

The drawing amount of the central core 4C is appropriately set depending on the processing accuracy. However, if the processing accuracy is ± 75 μm, and if 125 μm is aimed at, it is 50 to 200 μm. If the retraction amount is too large,
Although the length of the joint with the back bar is reduced and the magnetic resistance is increased, the electromagnetic conversion characteristics are affected. However, in view of the general dimensions of the magnetic head, there is no problem in this range.

Next, as shown in FIGS. 1 (a), 1 (b) and 1 (c), an end face of the outer core 4D having a recording / reproducing gap 4A in the medium traveling direction is provided on the front core 4 of the slider 3 having the same direction. It has a protrusion 4E protruding from the end face. The protrusion of the protrusion 4E is about 50 to 300 μm, and its end face has an accurate predetermined distance from the recording / reproducing gap 4A.

Further, as shown in FIG. 2 (b), a pair of cantilever-like outer projecting pieces 2E, 2E formed in the opening 2C of the cymbal 2.
Is provided outside both outer cores 4D, 4D of the front core 4 to be incorporated, and the tip is exactly parallel to the Y axis.
It is set to be at a predetermined distance from the Y axis. The protruding length of the central protruding piece 2D is shorter than the outer protruding piece 2E by almost half the thickness of the front core 4. The lower end of the center core 4C of the front core 4 is mounted on and bonded to the tip of the center protruding piece 2D of the gimbal 2 by approximately half.

Further, as shown in FIG. 1 (b), the back bar 5 has an extension 5A outside the outer width W of the outer cores 4D, 4D and is set so as to protrude from the back surface of the gimbal 2. . The total length of the back bar 5 is L, and each extension 5A is 100-300 μm.
It has a length of about m.

As shown in FIGS. 7 (a) and 7 (b), in the magnetic gap assembly depth setting step of the magnetic head assembly 34, the lower ends of the outer cores 4D, 4D merely serving as reference surfaces and the sliders 3A, 3B are formed. The lower end and the lower surface of the front core 4, which is a reference surface of the dimension T which is a reference of the gap depth, are simply placed on the same bottom surface of the jig 8 and applying pressures P1 to P5 from each direction. Since the lower surfaces of the sliders 3A and 3B, which are the reference surfaces for processing, are aligned on the same surface, the gap depth can be realized with higher accuracy and lower cost than the conventional configuration.

On the other hand, this magnetic head assembly 34 is shown in FIG.
As shown in FIG. 2 (b), the positioning of the magnetic gap at a predetermined position when the magnetic gap is assembled on the gimbal 2 is performed by positioning the outer projecting pieces 2E and 2E as shown in FIGS. 2 (a) and 2 (b). By contacting the extension 5A of the back bar 5 with each of them, the positioning in the X-axis direction and the setting of the angle of the recording / reproducing gap 4A with respect to the Y-axis can be further cured using the end face of the protrusion 4E of the front core 4 as a reference plane. By using a tool, positioning in the Y-axis direction is performed.

In addition, since the tip of the center protruding piece 2D of the gimbal opening 2C is bonded to form a doubly supported beam, there is no danger of deformation even if the support center 2F of the pivot of the head carriage receives an instantaneous impact force. You can now avoid it.

In the magnetic head gimbal assembly according to the present embodiment, the positioning accuracy is improved about three times as compared with the conventional method, and the angle error is reduced to about 1/2.

In the present embodiment, the case where a two-piece type slider is adopted as the slider has been described. However, the configuration of the present invention is also applicable to the case where an integral type slider having a core slit is adopted, in which case the magnetic gap is used. The end surface of the slider may be used as a reference for positioning in the Y direction.

〔The invention's effect〕

As described above, according to the present invention, by configuring the front core and the lower end surface of the slider to be substantially the same surface, highly accurate positioning of the magnetic gap becomes possible, and in particular, the upper and lower magnetic heads in the double-sided magnetic head are used. The time and equipment required for adjusting the magnetic gap could be saved, which was effective in reducing the cost of floppy disk drives.

[Brief description of the drawings]

FIG. 1 is a view showing a magnetic head gimbal assembly according to one embodiment of the present invention, wherein (a) is a top view, (b) is a bottom view, and (c) is an AA cross section of (b). FIG. 3D is a sectional view taken along line BB, and FIG. 3E is a sectional view taken along line CC. 2A and 2B are diagrams showing a main part of the magnetic head gimbal assembly of FIG. 1, wherein FIG. 2A is a side view and FIG. 2B is a bottom view. FIG. 3 is an assembly view of a conventional magnetic head assembly. FIG. 4 is a top view of a conventional magnetic head gimbal assembly, and FIG. 5 shows a main part of the conventional magnetic head gimbal assembly.
Is a side view, and (b) is a rear view. FIG. 6 is a schematic view of positioning a magnetic gap with respect to a conventional slider. 7A and 7B are views for explaining a step of extracting the depth of the magnetic head assembly of the magnetic head gimbal assembly of FIG. 1, wherein FIG. 7B is a side view and FIG. 7A is a cross-sectional view taken along the line AA of FIG. . 2 ... Gimbal, 2C ... Open hole, 2E ... Outer projecting piece, 3 ... Slider, 4 ... Front core, 4A ... Recording / playback gap, 4B ... Erase gap, 4C ... Center core 4D: outer core, 5: back bar, 5A: extension, 6: electromagnetic coil.

Claims (2)

(57) [Claims] 1. A front core having an outer core joined to both sides thereof with a central core interposed therebetween, the front core having a recording / reproducing gap and an erasing gap facing each of the outer core and a medium running surface of the central core. An electromagnetic coil is disposed on each of the outer cores, and a back bar is abutted and held at a lower end portion of a foot of each core of the front core so as to close a magnetic path of the front core, thereby holding the front core. A magnetic head assembly having a configuration in which a slider is adhered to the magnetic head gimbal assembly, wherein the magnetic gap is positioned at a predetermined position on a gimbal. Are positioned substantially on the same plane as the lower end of the slider, and the lower end of the central core is set 50 to 200 μm shorter than the lower end of the outer core. Umbal assembly. 2. The back bar has an extension extending at least beyond the back surface of the gimbal and outside of each of the outer cores of the front core, and the gimbal has a cantilevered projecting piece. 2. The magnetic head gimbal according to claim 1, wherein an opening for penetrating the back bar is provided, and a predetermined positioning is performed by abutting a tip of the protruding piece against each of the extension parts. Assembly.