JP2859468B2 - Magnetic head and method of manufacturing magnetic head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head for recording / reproducing information while moving relative to a magnetic medium such as a magnetic disk, and a method of manufacturing the same. And a method for manufacturing the same.

[0002]

2. Description of the Related Art In general, a magnetic head 1 for recording / reproducing information on / from a hard disk which is a recording medium of a magnetic recording apparatus such as a computer has a support as shown in FIGS. 6A and 6B. The apparatus 2 is attached to the tip of an elastic arm and suspended above the magnetic medium 3. Then, by rotating the magnetic medium 3, a floating magnetic head that floats the magnetic head 1 by a smaller gap than the magnetic medium 3 or a contact magnetic head that does not float the magnetic head 1 from the magnetic medium 3 The recording or reproduction is performed by scanning the surface of No.3.

As an example of this type of magnetic head, a small 2
Rail monolithic ferrite heads are known. As shown in FIG. 7, the ferrite head 4 includes a substantially rectangular slider 5 formed of high-density ferrite made of sintered ferrite such as polycrystalline Mn-Zn ferrite subjected to hot isostatic pressing. ABS (Air Be), which is a facing surface of the slider 5 facing the magnetic medium.
a negative pressure groove 7 for floating the ferrite head 4 with respect to the magnetic recording medium 3 on the surface 6 of the magnetic recording medium 3.
Are provided in parallel with the direction of relative movement with respect to the magnetic medium, and 2
Book rails 8a and 8b are formed. One rail 8 a and a substantially U-shaped head core 9 formed of high-density ferrite are joined by a glass 11 via an appropriate gap 10. And this head core 9
A narrow recording / reproducing section 13 corresponding to the track width is formed at the center of the rail 8a of the slider 5 and the end of the rail 8a by shaving both parts. The recording / reproducing section 13 is reinforced by joining the glasses 12, 12.

Conventionally, in this type of ferrite head 4, the ABS surface 6 and the bottom surface 14, which is not facing the magnetic medium, are generally parallel to each other and formed in a plane. It is a target.

The ferrite head 4 is shown in FIGS.
When applied to the magnetic head 1 shown in FIG.
When the magnetic medium 3 is in contact with the magnetic medium 3 in a stationary state, the magnetic medium 3 adheres to the magnetic medium 3 by suction, and the frictional resistance increases when the rotation of the magnetic medium 3 starts or ends. For example, the torque of the motor for rotating the motor 3 was increased.

Therefore, CSS (contact start,
A magnetic head in which the ABS surface 6 of the ferrite head 4 has a crown shape in order to improve the stop and sliding characteristics and the apex of the crown shape is brought into contact with the magnetic medium 3 is disclosed in, for example, Japanese Patent Application Laid-Open No. 2-50307. No. 1993.

[0007] As a manufacturing method for forming the ABS 6 in a crown shape, a processing method in which an R process matched with a desired curvature to be formed on the ABS 6 is applied to a surface plate used for lapping and polishing processes. And ABS
A processing method of performing lapping and polishing while moving the surface 6 in accordance with a desired curvature, and utilizing the deformation by lapping and polishing by forcibly applying an external pressure to the ferrite head 4 with a jig or the like. There is a method such as doing.

[0008]

However, in the above-mentioned conventional manufacturing method for forming the ABS surface in a crown shape, the processing accuracy of the crown shape is insufficient, and the setup time and the processing time during the processing of the crown shape are insufficient. In addition, there are many problems, such as a lot of management items, a lot of trouble, and a low yield. Therefore, the conventional magnetic head has a problem that the reliability of the crown shape on the ABS is inferior.

[0009] The present invention has been made in view of these points, and overcomes the above-mentioned problems in the conventional art.
A magnetic head having a highly reliable ABS surface crown shape is provided, and the ABS surface can be formed in a highly reliable and extremely reliable crown shape by a simple method. On the ABS
Direction parallel to and perpendicular to the direction of movement relative to the magnetic medium
The magnet can also be formed by selecting one or both of
It is an object of the present invention to provide a method for manufacturing a magnetic head and a magnetic head.

[0010]

According to the present invention, there is provided a magnetic head comprising:
The slider is characterized in that the slider has a crown formed at least in the direction parallel to the relative movement direction of the ABS surface with respect to the magnetic medium due to the residual stress caused by the magnetic effect .

According to a second aspect of the present invention, in the method of manufacturing a magnetic head according to the present invention, after the ABS surface and the bottom surface of the magnetic head are processed into a plane parallel to the magnetic head, one of the ABS surface and the bottom surface is added to the magnetic head.
The surface is processed to have a roughness different from that of the machined surface, and at least a direction parallel to a direction of relative movement of the ABS with respect to the magnetic medium is formed into a crown shape by residual stress.

[0012]

According to the magnetic head of the present invention, due to the residual stress due to the Twyman effect , the ABS of the magnetic head moving relative to the magnetic medium at least in a direction parallel to the relative movement direction (hereinafter referred to as a vertical direction). (Referred to as the direction), the ABS surface has a small contact area between the ABS surface and the magnetic medium when it is in a stationary state, and the ABS surface is reliably prevented from sticking by suction. When the rotation of the magnetic medium starts or ends, the frictional resistance increases, and the adverse effects of damaging the magnetic medium and increasing the torque of the motor that rotates the magnetic medium can be reliably prevented . According to the method of manufacturing a magnetic head according to the second aspect of the present invention ,
Processing so that the surface roughness of the ABS surface and the bottom surface are different,
Due to the residual stress due to the Twyman effect, the magnetic head A
A crown shape must be formed at least in the longitudinal direction of the BS surface .
Therefore, it can be easily formed by a general processing method, and the crown shape can be accurately and reliably formed on the ABS surface.

[0013]

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

FIG. 1 shows an embodiment of a magnetic head according to the present invention, and the same parts as those in the above-described conventional example are denoted by the same reference numerals in the drawings.

The present embodiment is applied to a small, two-rail monolithic ferrite head. As shown in FIG. 1, the ABS surface 6 of the ferrite head 4 facing the magnetic medium 3 is at least vertically extended. It is formed so as to have a crown shape.

Next, a method of manufacturing the ferrite head 4 according to this embodiment will be described with reference to FIGS. In FIG. 2, the ABS is turned upward for convenience of explanation.

FIG. 2A shows a magnetic head in the process of being machined until immediately before machining the ABS 6 into a crown shape. A long slider block serving as a material for the slider 5 and a head core 9 are shown. A long core block as a material is joined while holding a glass 11 to form a gap 10, and the upper and lower surfaces of the long object are integrally polished and formed to a predetermined thickness. Negative pressure grooves 7 are formed in the upper surface to form two rails 8a and 8b, and unnecessary portions of the core block are cut to form one rail 8a.
2 shows a state in which a head core 9 opposed to the head core 9 via a gap 10 is formed, and a single magnetic head is cut out from this long object.

Thereafter, as shown in FIG.
The surface roughness is improved by lapping the low surface 14 with diamond powder and mirror-finish the magnetic head in the process of processing in which the low surface 14 of the slider 5 and the low surface 14 of the slider 5 are in parallel with each other. As shown in (1), a crown shape is formed on the ABS 6 by the Twyman effect.
Thereafter, the corners of the two rails 15a and 15b formed in the crown shape of the head core 9 and the slider 5 are subjected to a predetermined chamfering process. Then, a necessary finishing process is further performed to form a small two-rail monolithic ferrite head 4 as shown in FIG. 2B and FIG.

Next, the formation of a crown shape on the slider 5 of the ferrite head 4 using the Twyman effect in the above-described method of manufacturing a magnetic head will be described together with its operation by way of a specific example.

First, the Twyman effect will be described. For example, when one surface (a lower surface in this example) of a flat rectangular object 16 shown in FIG. 3A is subjected to processing such as polishing, lapping, and polishing, A damaged layer 17 is formed on the processed surface, and residual stress is accumulated in the damaged layer 17. Then, the stress on the surface on which the work-affected layer 17 is formed is different from the stress on the other surface, and the internal stress balance in the initial state of the entire work 16 is changed.
As shown in FIG.

Next, as for the relationship between the deformation due to the Twyman effect and the residual stress, as shown in FIG.
A model in which a plate having a thickness H is deformed in the length direction will be described. As shown in FIG. 4A, after lapping the upper and lower surfaces, the work-affected layer is removed by etching to remove a sample having no residual stress. obtain.

Then, when the upper surface of the sample is polished to provide a work-affected layer 17, the sample is deformed as shown in FIG. The amount of deformation δ at this time is measured.

Next, as shown in FIG. 4C, the surface other than the surface of the work-affected layer 17 formed by polishing the upper surface of the sample is covered with a resin 18, and the work-affected layer 17 is etched. Removed by processing. At this time, the thickness a of the affected layer 17 removed by the etching treatment is measured.

Then, as shown in FIG. 4D, after removing the resin 18 coated on the sample, the deformation amount δ is measured again. The above process is repeated until there is no change in the amount of deformation, and when the amount of deformation when the affected layer 17 is completely removed is δ ′, the residual stress σ of the affected layer 17 can be obtained by the following equation. .

[0025]

Here, E is an elastic coefficient.

By controlling the deteriorated layer provided on the processing surface as described above, a crown shape utilizing the Twyman effect by the residual stress balance can be provided in the magnetic head. The method of forming the crown shape by processing the bottom surface 14 of the magnetic head to increase the compressive stress of the bottom surface 14 and the method of processing the ABS surface 6 of the slider 5 to reduce the compressive stress of the ABS surface 6 There is a way to reduce it.

FIG. 5 shows that # 4
One example of the relationship between the depth from each surface and the residual stress in the polished surface with a 00 grindstone and the affected layer 17 formed on the lapping surface with diamond powder having a particle diameter of 3 μm is shown.

In the above-described example, the Mn-Zn ferrite has a polished surface having a compressive stress of 24 MPa by a # 400 grindstone on one surface and a lapping surface having a compressive stress of 42 MPa by diamond powder having a grain size of 3 μm on the other surface. A polished sample is prepared, and one of the polished surfaces is further wrapped with diamond powder having a particle size of 3 μm. The polished surface becomes a lapping surface having a compressive stress of 42 MPa, and the lapping surface that has been processed thereafter shrinks, whereby the lapping surface that has been previously wrapped is formed into a crown shape.

As described above, since the residual stress is determined by the state of the work-affected layer 17, generally, in processing such as polishing, lapping, and polishing, the surface stress and the residual stress are set between the surface roughness and the residual stress. There is a correlation that the compression stress increases as the surface roughness decreases. From this, by increasing the difference between the surface roughness before processing and the surface roughness after processing,
The amount of deformation of the crown shape can be increased, and by setting the difference between the surface roughness before processing and the surface roughness after processing to a desired value, the desired amount of crown shape deformation (crown height amount) Can be obtained.

Then, several nanometers / mm
The desired crown height can be set within the range of the crown height from 100 to several hundred nm / mm.

Further, the direction of deformation of the crown shape can be set to any one of a longitudinal direction of the ABS surface 6 of the slider 5 and a direction perpendicular thereto (hereinafter, referred to as a lateral direction) or a bidirectional direction. 6 can be freely selected as either the vertical direction, the horizontal direction, or both directions.

In the ferrite head 4 manufactured according to this embodiment, at least one of the ABS surface 6 and the bottom surface 14 is a mirror surface, and both the ABS surface 6 and the bottom surface 14 are deformed with substantially the same curvature. It has the feature of.

In the above embodiment, the slider 5 of the magnetic head was manufactured by subjecting the ABS 5 to a crown shape, but the slider block and the core before cutting the slider 5 of the magnetic head alone were manufactured. A portion to be an ABS may be processed into a crown shape for a long object to which a block is joined.
In this case, the crown shape of the ABS surface is deformed by the subsequent processing. It is preferable to predict the amount of the deformation and perform the processing so as to have a crown shape that can be used even if there is deformation.

Note that the present invention is not limited to the above-described embodiments, and various modifications can be made as necessary.

The present invention is not limited to the ferrite head of the above embodiment, but can be applied to a composite magnetic head such as a composite ferrite head. The same can be applied to a head.

[0037]

As described above, according to the present invention is, Towaima
Processing to generate residual stress due to the
For example , after processing the ABS surface and the bottom surface of the slider into a parallel plane, one of the ABS surface and the bottom surface is different from the processed surface.
By processing the surface roughness , the slider is provided with a crown-shaped ABS surface having a desired crown height amount that is highly accurate and highly reliable by a simple method,
A magnetic head can be obtained, and the crown can be obtained.
The shape is parallel to the relative movement direction of the ABS surface to the magnetic medium
Direction and at right angles, and both.
Rukoto also, the magnetic head having such excellent technical effect, precisely can be easily manufactured, also an effect such as whereby a composition with remarkably superior economics.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the whole of a magnetic head of the present invention applied to a small-sized two-rail monolithic ferrite head.

FIGS. 2A and 2B are views showing a manufacturing process when a small 2-rail monolithic type is manufactured according to the magnetic head manufacturing method of the present invention. FIGS.

3A and 3B are diagrams for explaining the Twyman effect.

4A to 4D are diagrams illustrating a process of examining a relationship between deformation due to the Twyman effect and residual stress.

FIG. 5 is a diagram showing an example of the relationship between the depth from the surface of a work-affected layer and residual stress.

6A and 6B are diagrams showing a state of support of a conventional magnetic head, wherein a is a front view and b is a side view.

FIG. 7 is a perspective view showing a conventional small two-rail monolithic ferrite head.

[Explanation of symbols]

 Reference Signs List 4 Ferrite head 5 Slider 6 ABS surface 7 Negative pressure groove 9 Head core 14 Bottom 15a, 15b (Crown-shaped) rail 17 Work-affected layer

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-186572 (JP, A) JP-A-4-167279 (JP, A) JP-A-64-76418 (JP, A) JP-A-62-162 166934 (JP, A) Japanese Utility Model Showa 62-110764 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G11B 21/21 101

Claims (2)

(57) [Claims] 1. Due to the residual stress due to the Twyman effect ,
A magnetic head comprising a slider in which at least a direction parallel to a relative movement direction of an ABS surface with respect to a magnetic medium is formed in a crown shape. 2. After processing the ABS surface and the bottom surface of the slider into a parallel plane, one of the ABS surface and the bottom surface is processed by the processing surface.
Surface roughness different from that of
A method of manufacturing a magnetic head, comprising: forming a crown shape at least in a direction parallel to a relative movement direction of a BS surface with respect to a magnetic medium.