JPH0560165B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a magnetic head, and more particularly to a magnetic head that is composed of a magnetic core and a coil wound around the magnetic core that performs electromagnetic conversion of recording/reproducing signals. It is related to.

[Summary of the Disclosure] This specification and drawings describe a magnetic head of the type described above, in which a plurality of short ring coils are wound around a magnetic core in addition to the electromagnetic conversion coil, and the short ring coils are cut. This invention discloses a technique that makes it possible to make the magnetic characteristics of the magnetic head uniform and reduce manufacturing costs by adopting a configuration in which the impedance of the magnetic head is adjusted depending on the number of magnetic heads.

[Prior Art] A very general conventional structure of the head body of the type of magnetic head described in the field of industrial application is shown in FIG. That is, a bobbin 3 on which the above-described coil 2 is wound is fitted to the rear of a ring-shaped magnetic core 1 having a magnetic gap G on the sliding surface of the magnetic recording medium at the tip.
A connecting terminal 4 is implanted in which both ends of the connecting terminal 4 are connected. Then, this head main body is fitted with a core holder (not shown) and then fitted into a shield case (not shown) and circumferentially formed to form a laminated head.

[Problems to be Solved by the Invention] In the above-mentioned magnetic head, material management,
A number of measures have been taken, such as controlling manufacturing processes and improving processing methods.

However, variations in magnetic properties can ultimately be suppressed within a certain range, but cannot be suppressed completely. Therefore, it is necessary to rank the heads by selecting their characteristics, or to set the heads in a magnetic recording/reproducing device and then improve the device side. adjustments are commonly made.

However, the increase in the number of adjustment steps on the device side causes an increase in the manufacturing cost of the device, and in the manufacture of magnetic heads, unnecessarily spending money on the above-mentioned management and the like poses a problem.

[Means for Solving the Problems] In order to solve these problems, according to the present invention, in the magnetic head of the above-mentioned type, a short ring coil is provided in the magnetic core in addition to a coil for electromagnetic conversion of recording/reproducing signals. A plurality of short ring coils are provided, and the impedance of the magnetic head is adjusted by the number of short ring coils to be cut.

[Function] As shown in FIG. 1, a printed circuit board 5 is fitted into the magnetic core 1 of the head body along with a bobbin 3 around which a coil 2 for electromagnetic conversion of recording and reproduction signals is wound. As shown in FIG. 2, a plurality of short ring coils 6 are formed on this printed circuit board 5, surrounding a hole 5a for fitting into the magnetic core 1.

According to this structure, the short ring coil 6 cancels out a part of the magnetic flux generated from the coil 2 during recording.
As a result, the impedance of the magnetic head is lowered by the provision of the short ring coil 6.
If the shot ring coil 6 is cut to remove its effect, the impedance will increase accordingly.
Therefore, the impedance of the magnetic head can be adjusted by changing the number of cut ring coils 6, and the magnetic characteristics of the magnetic head can be made uniform very easily. Further, it is possible to eliminate the need for adjustment on the magnetic recording/reproducing apparatus side, which is performed by setting the magnetic head.

[Example] Hereinafter, details of embodiments of the present invention will be described.

First Embodiment FIG. 1 shows the structure of a head main body of a magnetic head according to a first embodiment of the present invention.

The reference numeral 1 designates a magnetic core, which is constructed by a pair of core halves formed from a laminate of magnetic thin plates butted against each other via a magnetic gap G and joined together. Also, what is indicated by the reference numeral 3 is a bobbin, around which is wound a coil 2 for electromagnetically converting a recording/reproduction signal, and a connecting terminal 4 to which both ends of the coil 2 are connected.
4 is implanted and fitted into the rear part of the magnetic core 1.

The configuration of the magnetic core 1 and the coil 2 is the same as the conventional one, but in this embodiment, in addition to this, a printed circuit board designated by reference numeral 5 is fitted into the rear of the magnetic core 1 adjacent to the bobbin 3. are combined.

The printed circuit board 5 has the configuration shown in FIG. 2, and has a hole 5a in the center into which the magnetic core 1 is fitted, and a plurality of holes, three in this case, on the surface around the hole 5a. A ring coil 6, ie an independent closed loop coil, is formed. The short ring coils 6 are formed into rectangular shapes that are similar but have different dimensions so as not to come into contact with each other.
are arranged concentrically.

According to the structure in which the short ring coil 6 is provided separately from the coil 2, a part of the magnetic flux generated from the coil 2 during recording is canceled out by the short ring coil, and the impedance of the head is reduced accordingly. If the short ring coil 6 is cut off to remove its effect, the impedance will increase accordingly. Therefore, the impedance of the head can be adjusted by changing the number of short ring coils 6 to be cut.

In this example, after completing the assembly of the head body, its impedance was measured, especially in the high range (50KHz~
100KHz), the number of shot ring coils 6 is cut according to the amount of deviation from the specified range of the measurement results, and the impedance value is brought within the specified range.

In this way, the impedance value of the magnetic head can be adjusted within a specified range, and the bias current value used in the magnetic recording/reproducing device in which the head is set is determined according to this impedance value, so the bias current adjustment value can be fixed. , it is possible to eliminate the need for adjustment on the device side after setting.

Second Embodiment FIG. 3 shows the structure of a printed circuit board 5 according to a second embodiment of the present invention.

As shown in the figure, the printed circuit board 5 of this embodiment has an extended rear portion located on the opposite side of the magnetic gap G compared to that of the first embodiment. Each of the ring coils 6 is similarly extended.

In this embodiment, due to such extension, core holders 7, 7 are provided on both sides of the head body, as shown in FIG.
and the head body is fitted and fixed in the shield case 8 so that the rear end portions of the printed circuit board 5 and short ring coil 6 are exposed from the shield case 6 when the entire magnetic head assembly is completed. It is configured.

According to this structure, the exposed rear end of the shot ring 6 is marked by the broken line A or B in FIG. You can adjust the impedance by cutting it as shown.

[Effects of the Invention] As is clear from the above description, according to the magnetic head of the present invention, the magnetic characteristics of the magnetic head can be made uniform very easily by adjusting the impedance by adjusting the number of cut rings. Further, providing a shot ring is structurally reasonable and can be implemented at low cost, and conversely, manufacturing costs can be reduced by simplifying management to make the characteristics uniform. Furthermore, it is possible to eliminate the need for adjustment when combined with a magnetic recording/reproducing device, thereby reducing the manufacturing cost of the magnetic recording/reproducing device.

[Brief explanation of the drawing]

FIG. 1 is a front view showing the structure of a head body of a magnetic head according to a first embodiment of the present invention, and FIG.
3 is a front view of the printed circuit board according to the second embodiment, FIG. 4 is a partially cutaway front view of the magnetic head of the same embodiment, and FIG. 5 is a front view of the conventional head body. It is a front view. 1...Magnetic core, 2...Coil, 3...Bobbin, 4...
Connection terminal, 5... Printed circuit board, 6... Short ring coil, 7... Core holder, 8... Shield case.

Claims (1)

[Scope of Claims] 1. A magnetic head consisting of a magnetic core and a coil wound around the magnetic core for electromagnetic conversion of a recording/reproducing signal, in which a plurality of short ring coils are wound around the magnetic core in addition to the coil. A magnetic head characterized in that the impedance of the magnetic head is adjusted by the number of cut ring coils. 2. The magnetic head according to claim 1, wherein the plurality of short ring coils are formed on one printed circuit board.