JPH02240810A - Multigap magnetic head - Google Patents

Abstract

PURPOSE:To minimize a output loss by forming the shape of the sliding surface of the multigap magnetic heads disposed with plural gaps on the sliding surface to the assemblage of projecting curved surfaces, the vertexes of which are respective gap positions and setting the ridge lines of the respective curved faces in the direction in contact with plural pieces of virtual ellipses. CONSTITUTION:The positions of the gaps 3a, 3b in the sliding surface of the head are the parts projecting most to a tape 20 side and, therefore, if the magnetic head is slid in the state of pushing the head to the magnetic tape 20, the contact pressure with the tape 20 is maximized and the spacing quantity is minimized to minimize the output loss. The positions of the ridge lines 12a, 12b in the sliding surface are next larger in the pressure and the tape 20 is extended along the ridge lines 12a, 12b and receive deformation. Since the ridge lines 12a, 12b are aligned to the tangent of the virtual ellipse 14, the deformation of the tape 20 builds up in the shape which is like a contour line 16. The ellipse 14 is formed symmetrical with respect to the sliding axis 10 by selecting the aspect ratio thereof so as to minimize the area thereof and, therefore, the area of the deformed part is minimized and the tape 20 slides smoothly without having torsion.

Description

[Detailed description of the invention] [Industrial application field] In the present invention, a plurality of gaps are arranged on the sliding surface ff1L.

The present invention relates to a multi-gap magnetic head having a structure that realizes good contact with a flexible medium.

[Conventional technology]

As is well known, in performing short wavelength recording, it is important to reduce the amount of spacing between the magnetic head and the medium and to reduce the loss associated with this. In particular, in the case of a multi-gap magnetic head having a plurality of gaps for recording or reproducing, which are arranged physically close to each other, it is necessary to keep the amount of spacing at each gap position uniform and extremely small. As related prior art, 9, for example, Japanese Patent Application Laid-Open No. 62-5711
There is a magnetic head described in Publication No. 6. FIG. 7 shows an example of this, in which there are two gaps 3α and 3b in the track width direction, and grooves 18 parallel to the sliding direction are formed in the center and outside of each gap.

Due to the relative movement of the magnetic head and the medium, the air pressure in the groove portion of the sliding surface is reduced, and the flexible medium is attracted toward the magnetic head, which has the effect of reducing the amount of spacing.

Separately, in helical scan magnetic heads for VTRs, etc., in order to improve the envelope at the tape entry and exit positions, the spacing is made so that the ridgeline direction of the sliding surface is parallel to the tape running direction. A method of reducing this has been proposed. (Japanese Unexamined Patent Publication No. 63-50912) [Problems to be Solved by the Invention] The above-mentioned prior art is directed to the case where the gaps are arranged on the same line and perpendicular to the sliding direction.

However, if the number and arrangement of the gaps are arbitrary, that is, the gaps are not on the same line, and the direction thereof obliquely intersects the sliding direction at an arbitrary angle, the above-mentioned conventional groove formation alone is insufficient. The reason for this is (1) If only the grooves are formed, each gap position does not coincide with the apex of the curved surface, so the amount of spacing increases.

(2) If the active surface shape is asymmetrical with respect to the sliding direction as the central axis, torsional deformation of the medium will occur, and the resulting vibration of the medium will make the spacing amount and tracking unstable.

Conventional technology has been unable to solve these problems at the same time.

The object of the present invention is to compensate for the drawbacks of the above-mentioned prior art.

It is an object of the present invention to provide a structure in which the spacing amount of a multi-gap magnetic field is minimized and maintained stably with arbitrary gap arrangement.

(Means for Solving the Problems) The above object is to make the sliding surface of a multi-gap magnetic head a collection of convex curved surfaces with vertices at each gap position, and to pass through each gap position with the sliding direction as an axis. This is achieved by drawing one virtual ellipse with the smallest area or a plurality of coaxial virtual ellipses, and making the ridgeline direction of the convex curved surface near each gap approximately equal to the tangential direction of the virtual ellipse.

In particular, regarding a pair of gaps located at point-symmetrical positions within a sliding surface, when the direction of the straight line connecting them is inclined by an angle of 0 from the sliding direction, the ridgeline direction of the convex curved surface of each gap is set opposite to the sliding direction. It was made to tilt to the side by an angle θ.

Note that the ridgeline herein means a line obtained by taking a cross section of the convex curved surface perpendicular to the sliding direction and connecting the vertices of each cross section.

[Effect]

Since the positions of each gap on the magnetic head sliding surface are at the vertices of the convex curved surface, the flexible medium makes good contact with each gap, minimizing the spacing.

Furthermore, since the ridgeline of the convex curved surface of each gap is set as the tangential direction of the virtual ellipse with the sliding direction as the axis, the deformation of the entire medium follows this virtual ellipse, that is, this deformation is symmetrical with the sliding direction as the axis. It becomes smooth and no twisting deformation occurs.

Therefore, the vibration of the medium is small, and spacing and tracking can be kept stable.

〔Example〕

Hereinafter, two embodiments of the multi-gap magnetic head of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows the first embodiment of the present invention, in which there are two gaps, (α) is a plan view (view from the sliding surface), (
b) is a side view, (C) is a partially enlarged view of figure (α), (d)
is a sectional view of FIG.

To explain the configuration, 1α and lb are a pair of head elements,
It consists of magnetic cores 2a, 2b made of ferrite or the like, and gaps 3α, 3b for recording and reproduction. 4 is filled glass, 5c
L, 55 is a winding coil.

A pair of head elements ICL and lb are supported by a holder 6,
Attach to the outside (for example, a rotating cylinder) with screw 7. A multi-gap magnetic head slides in a straight line 10.degree. 10' relative to a flexible medium such as a magnetic tape (not shown).

A pair of gaps 3α.

The direction connecting 3C is inclined by an angle θ with respect to the sliding direction 10, as shown by straight line 11Al1. - As an example, the gap distance is IAx=1m, Ity=0.5an, where Ax is the sliding direction and Ly is the perpendicular direction.

The sliding surface of each head element, which shows the case where the angle θ = 26°, has a convex curved surface shape with the apex at the gap position, and the sliding surface is shown in FIG. The cross-sectional shape at the cut AA' perpendicular to the direction is shown in figure (d). The sliding surface is a convex curve, the apex position of which is indicated by 13, at the cut AA'.
is moved in the sliding direction 10', and the apex 13 at each cross section is
The line connecting them is a dotted line 12 (shown thickly), and this line will hereinafter be referred to as an edge 1IA12. In this figure, the edge line 12 is parallel to the longitudinal side surface 8 of the head element. Each ridgeline 12α.

The angles φα and φb formed with the direction of 12b, that is, the sliding direction 10 (10'), were determined as follows. A virtual ellipse (-dotted chain line) 14 is drawn on the sliding surface, passing through the pair of gaps 3α and 36 and having the smallest enclosing area.

A tangent line drawn to this virtual ellipse 14 at each gap position (-
Dotted chain line) 15, assuming 1513, the above ridge line 12α,
12C was made to almost coincide with the tangents 15α and 156. The above contents will be explained using mathematical formulas. Using xy coordinates with the sliding direction as the
), then the angle θ between the straight line 11 connecting the gaps and the sliding direction 10 is.

a=j a n-" (b/c), and the formula for the virtual ellipse 14 with the minimum area is x"/2 a-"+y"/2 b"=1, that is, the apex is (±V21. 0), (0, ±V/2b). Gap position (α, b), (−α.

The equation for the tangent 15 at -b) is x/2α+y/2 b = ±1, so its slope is d y / d x = -b /
Since the CL ridge line 12 is made to coincide with these tangent lines 15, its angle becomes φα=φb=tan′ (−b/a)=−θ. That is, the direction of the ridge line 12 is inclined by an equal angle to the direction connecting the pair of gaps and the opposite side to the sliding axis.

Next, Figure 2 is number 11 above! This is a diagram showing the operation of the multi-gap magnetic head described in Section 1. ((L) is a plan view.

(b) is a sectional view taken along line BB' in figure (L).

When the magnetic head is pushed into the magnetic tape 20 and slid, a gap 3α is formed in the head sliding surface.

Since the position 3b is the part that most protrudes toward the magnetic tape 20, the contact pressure with the magnetic tape 20 is maximum and the spacing amount is minimum. Therefore, the output loss caused by this becomes extremely small. Among the other sliding surfaces, the ridgelines 12a and 12b
The position of the magnetic tape 20 has the second highest pressure, and the magnetic tape 20 is located along this ridgeline 12α.

12b and undergoes deformation. In the present invention, the ridgelines 12α and 12b are made to coincide with the tangents of one virtual ellipse 14, so that the magnetic tape 20 is deformed into a shape close to this virtual ellipse 14, which is shown by isolines 16. Here, as a condition for the virtual ellipse 14, an aspect ratio (eccentricity) that minimizes its area is selected, and the virtual ellipse 14 is made symmetrical about the sliding axis 10. Therefore, the area of the deformed portion is minimum, and the deformed shape is symmetrical in the width direction as shown in FIG. Such deformation of the magnetic tape realizes the smoothest and twist-free sliding form when the tape slides. Therefore, it is possible to maintain stable spacing and tracking without causing vibrations in the thickness direction or width direction when the tape slides.

FIG. 3 shows a second embodiment of the multi-gap magnetic head according to the present invention, (α) is a plan view, (b) is a partially enlarged view,
(C) is a sectional view. In this embodiment, each head element 1
α, external side surface 8α of 1b.

8b is arranged parallel to the sliding direction 10. On the other hand, ridge line 12c
, 12b are determined in the same manner as in the previous embodiment.

φ1=φb=-〇. Therefore, the ridge line 12 obliquely intersects the side surface 8 at an angle θ, as shown in FIG. 3B, and the cross section is asymmetrical, with the apex 13 shifting from the center as the position of the cut CC' is moved, as shown in FIG. However, in this embodiment as well, the deformation and sliding properties of the magnetic tape are exactly the same as in the first embodiment, and it has been found that only the directions of the edges 1i12α and 12b are important.

FIG. 4 shows a third embodiment of the multi-gap magnetic head according to the present invention, in which there are four gaps.
CL) is a plan view, and (b) is a side view.

Gaps 3α to 3d are arranged in a straight line 1IA11 at equal intervals and obliquely intersect with the sliding direction 10 at an angle θ. Angle φ between the ridge lines 121 to 12d at each gap position and the sliding direction 10
1 to φd were set to φα=φb=φC=φd=−〇. The virtual ellipse passing through each gap in this case is the gap LLO
L, the outer ellipse 14 passing through Lid, and the gap llb,
There are two inner ellipses 14' passing through llc. Since these ellipses are coaxial and have the same aspect ratio (eccentricity), the tangential directions at each gap position are also the same, so their ridgeline 12α
The direction of ~12d was also made equal. In this case, the magnetic tape 20
The deformation of is symmetrical in the width direction, no twisting occurs and sliding properties are stable. Furthermore, in this example, the height (protrusion amount) of the apex at each gap position.

Gaps on the same virtual ellipse have the same height.

The height of the gap on the inner virtual ellipse was increased.

In other words, in figure (b), the apex height of the inner gaps 3b and 3c with respect to the outer gaps 3o, 3d is set to ΔZ (several μm).
~ several + μm).

In this way, the spacing of each gap, especially the inner gap, can be minimized and uniform against deformation of the magnetic tape 20, thereby eliminating unbalanced recording and reproducing characteristics.

Next, FIG. 5 shows a fourth embodiment of a multi-gap magnetic head according to the present invention, which has four gaps and is arranged on two obliquely intersecting straight lines. (, l) is a plan view showing the gap 3 (L and 3b are arranged on the straight line 11, and the gaps 3C and 3d are arranged on the straight line 11').

The angles formed between these straight lines and the sliding direction are θ and θ′, respectively.
If so.

The directions of the ridge lines 12α to 12d at each gap position are as follows.

φ(L±φb=−θ, φC:+:φd=−〇′.

(b) is a side view showing the apex height at each gap position (
The protrusion amount) was set to have a difference of Δ2 according to the virtual ellipse 14.14'. The operation in this case is also similar to the previous embodiment.

The present invention is not limited to the above embodiments, but can be applied to any other number of gaps and arrangement thereof by drawing a plurality of virtual ellipses.

Furthermore, the present invention does not limit the core material constituting the magnetic head element. As an example, FIG. 6 shows the case of a multi-gap magnetic head made of a magnetic thin film as the magnetic core material. (moving surface).

(b) is a sectional view. The head elements 1α and 1b are.

Magnetic thin film core 2 (1°2
b and gap 3a, 3b and FJ Di Micoil 5゜5b
formed on a common substrate 17. Magnetic thin film core 2
The direction of the ridgeline 12α, 12b of α, 2b is the sliding direction 10
In this embodiment, a plurality of head elements can be arranged closely and with high precision, with the edge jIIA12α obliquely intersecting by a predetermined angle.

The processing of 12b can also be easily realized by a thin film etching process.

Although the above embodiment deals with a magnetic tape as the medium, it goes without saying that the multi-gap magnetic head of the present invention can also be applied to flexible magnetic disks.

〔Effect of the invention〕

As described above, according to the present invention, in a multi-gap magnetic head in which a plurality of gaps are arranged on the sliding surface, the shape of the sliding surface is an aggregate of convex curved surfaces with each gap position as a vertex. , the ridgeline of each curved surface was set in a direction tangent to one or more virtual ellipses. From this, (1) the contact pressure of the flexible medium at each gap position is increased, the spacing foot is minimized, and the resulting output loss is minimized;

(2) The heaving deformation of the medium when the head slides is symmetrical with respect to the sliding axis, and there is an effect such as 9 that spacing and tracking fluctuations accompanying torsional deformation are reduced.

[Brief explanation of drawings]

FIG. 1 is an embodiment of the multi-gap magnetic head of the present invention, in which (α) is a plan view and (b) is a side view. (c) is a partially enlarged view, (d) is a sectional view, FIG. 2 is an explanatory diagram of the operation of the embodiment of FIG. 1, and FIGS. 3 to 6 are diagrams. Another embodiment of the multi-gap magnetic head according to the present invention; FIG. 7 shows a conventional multi-gap magnetic head, (α) is a plan view, and (b) is a side view. 1...Head element. 2...Magnetic core. 3... Gap. 10...Sliding direction. 12...Ridge line. 14...Virtual ellipse. Muscle occipitalis Muscle occipitalis 4th muscle tb) (α) (b)

Claims (1)

[Claims] 1. In a multi-gap magnetic head in which a plurality of gaps are arranged on the sliding surface, the shape of the sliding surface is an aggregate of a plurality of convex curved surfaces with the apex at each gap position, and When one or multiple coaxial virtual ellipses with the smallest area are drawn passing through each gap position with the sliding direction as the axis,
A multi-gap magnetic head characterized in that the direction of each ridge line obtained by connecting the vertices of a cross section perpendicular to the sliding direction on the convex curved surface near each gap is substantially equal to the tangential direction to the virtual ellipse.