JPS63229603A - Magnetic head and its production - Google Patents

Abstract

PURPOSE:To produce a magnetic head of a VTR for business use, etc., without additionally providing special private equipments by joining auxiliary cores with both surfaces on opposite sides of surfaces abutting each other of magnetic core half bodies into one body so that auxiliary cores are extensions of a tape slide face. CONSTITUTION:A magnetic core having the same shape as the magnetic core used in the magnetic head of a home VTR is used in magnetic core half bodies 21 and 21', and auxiliary cores 29 and 29' are stuck to surfaces on opposite sides of abutting surfaces of magnetic core half bodies 21 and 21' so that auxiliary cores are a part of a tape slide face 25. Thus, a practical core width S1 is made wider than a core width S2 of the magnetic head of the home VTR and the magnetic head of the VTR for business use is produced without additionally providing special private equipments.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a magnetic head in a magnetic recording/reproducing device.
In particular, it relates to the structure of a magnetic head with a large tape sliding surface width and its manufacturing method.

(Prior art) Conventional home video tape recorder (hereinafter referred to as home VTR)
It is called. ), for example, VHS (registered trademark) has a drum diameter of 62φ and a drum rotation speed of 30 rotations/8eO, but professional VTRs record at a higher density, so for example, a drum diameter of 76φ and a drum rotation speed of 90 rotations. /Se
E., the drum diameter is increased and the drum rotation speed is increased, and it is thought that this trend will become stronger in the future.

FIGS. 6(a), 6(b), <C) are explanatory diagrams for explaining the relationship between the base protruding from the rotating drum of the magnetic head 10 and the R shape of the tip. As shown, the amount of protrusion of the magnetic head 10 from the drum outer peripheral surface 11 is tl, and the radius of the tip R of the magnetic head 10 is d.
In this case, the radius d is selected such that the edge portion 10a of the magnetic head does not protrude from the outer peripheral surface 11 of the drum in the direction of the magnetic tape 12.

If, for example, the protrusion amount t1 is as shown in FIG.
is increased to t2 (t2>jl), or Fig. 6 (a
), if the radius d of the tip R is increased, the edge portion 10a will protrude from the drum outer circumferential surface 11 in the direction of the magnetic tape 12, and when the magnetic head 10 rotates at high speed, it will come into direct contact with the magnetic tape 12 surface and become strong. As a result of the impact, the running properties of the magnetic tape 12 become unstable, leading to poor contact between the magnetic head and the magnetic tape. This causes spacing loss and sliding noise, and also causes damage to the magnetic tape 12.

In particular, this tendency has become even more pronounced as the drum diameter and drum rotational speed have become larger and the circumferential speed of the magnetic head has become larger, such as in commercial VTRs.

On the other hand, in household VTRs, magnetic heads 10 with a core width of about 2 to 31 cm are used, but when a magnetic head 10 with such a narrow core width is used in a high-speed rotating business VTR, wear resistance If the protrusion is determined to be constant in consideration of characteristics and tape touch, in order to prevent the edge portion 10a from protruding from the outer circumferential surface 11 of the rotating drum, the radius d of the tip R will be smaller than that of a magnetic head with a wide core width. Although it is necessary to make the radius d smaller, there is a limit to reducing the radius d, and if the dimension d of the tip R is made smaller, the sliding area with the magnetic tape 12 decreases, resulting in poor wear resistance. Also, due to usage problems such as difficulty in adjusting the contact between the magnetic tape 12 and the magnetic gap at the tip of the magnetic head, the magnetic heads used in professional VTRs have a width that is wider than that of the magnetic herad core of home VTRs. A magnetic head with a core width of around 3 to 4 mm, which is 5 to 2 times larger, was used. That is, even when the protrusion amount is set to t2 and the radius d of the tip is set to be equal to that shown in Fig. 6(C),
By increasing the core width, the edge portion 10a of the core does not need to protrude from the outer peripheral surface of the drum, and deterioration due to contact between the magnetic head and the magnetic tape can be avoided.

(Problems to be Solved) As mentioned above, when manufacturing a magnetic head having a core width larger than that of a home VTR magnetic head, it is difficult to use the manufacturing equipment for the home VTR magnetic head as is. However, there was a problem in that it was necessary to readjust the manufacturing machine or change the jig, which significantly hindered productivity.

One possible solution to this problem would be to have manufacturing equipment dedicated to large magnetic heads, but since the production volume of magnetic heads for professional VTRs is much smaller than that of magnetic heads for home VTRs, manufacturing equipment would require excessive costs. The introduction of this was not a good idea and was a major problem.

In addition, for example, when expensive high-Bs magnetic materials are used as the core material of a magnetic head in order to support recording media with high coercive force such as metal tapes, these high-Bs magnetic materials become larger as the magnetic path head becomes larger. There were problems such as increased usage and cost disadvantages.

(Means for Solving the Problems) The present invention has been made to solve the above problems, and includes a pair of magnetic core halves that are butted together with a non-magnetic gap material interposed between the butt surfaces, and tape sliding is performed. In a magnetic head having a magnetic gap formed on a sliding surface, an auxiliary core is integrally joined to both sides of the magnetic core halves opposite to the abutting surface so as to form an extension of the tape sliding surface. The present invention provides a magnetic head with characteristics and a method for manufacturing the same.

(Embodiment) FIG. 1 is a perspective view showing a magnetic head 20 according to a first embodiment of the present invention, and the following description will be made with reference to the same figure. 21.2
1' is a magnetic core half made of Sendust (registered trademark), for example, and a winding groove 22 is formed on the abutting surface of one magnetic core half 21, and the magnetic core half 21 is formed in this abutting surface.
．． 21' are abutted with a non-magnetic gap material such as 5i02 between the abutting surfaces, and are integrally joined by the molten glass 24 filled in a part of the bonding groove 23 and the winding groove 22 formed on the abutting surfaces, and then the tape Magnetic gap 26 on sliding surface 25
is formed. Reference numeral 27 denotes track width regulating grooves, which are formed as a pair of half-moon-shaped grooves near the top and bottom of the magnetic gap 26 on the tape sliding surface 25.
A track width is formed between them, and molded glass 28 is melted and filled in these track width regulating grooves 27.
It protects the magnetic core that forms the track width.

29.29' is an auxiliary core made of, for example, a ferrite magnetic material, which is a main part of the present invention, and the magnetic core half body 21
．． Tape sliding surface 25 is on the opposite side of the abutting surface of 21'.
630.3 joined together to form a part of
0' is the winding outer groove, and these winding outer grooves 30, 30'
A coil (not shown) is wound using the winding groove 22.

Since the magnetic head 20 according to the present invention has the above configuration,
For the magnetic core halves 21 and 21-, a magnetic core with the same shape as that used in the magnetic head of a household VTR is used, and an auxiliary material is used on the surface opposite to the abutting surface of the magnetic core halves 21 and 21-. Attach core 29゜29' and tape sliding surface 25
By forming the magnetic head 20 to become a part of the
As a result of forming the substantial core width S1 to be larger than the core width S2 of the household VTR head, it is possible to easily manufacture a magnetic head for a business VTR without adding any special dedicated equipment. Furthermore, since a magnetic core having the same shape as the magnetic core of a household VTR is used, even if the actual core width of the magnetic head is increased by $1, expensive sendust material is not consumed unnecessarily, which is advantageous in terms of cost.

In addition, as in the above embodiment, if a metal magnetic material such as Sendust is used for the magnetic core halves 21 and 21', the Q value becomes small and the amplifier resonance cannot be obtained large. By using magnetic ferrite for the core 29゜29- and winding a coil on top of this, the Q value can be increased, so auxiliary cores, etc., which were conventionally used to increase the Q value, are not necessary. This can simplify the process.

FIG. 2 is a perspective view showing a magnetic head 4o according to a second embodiment of the present invention, and explanation will be given using the same figure. The same components as in the first embodiment are denoted by the same reference numerals, and only different points are shown. Explain.

The difference from the first embodiment is that a high BS ferrite magnetic material that can be used with a metal tape having a high coercive force (1c) is used as the magnetic material for the magnetic core halves 21° and 21'. The auxiliary core 19.29- is made of ferrite magnetic material as in the first embodiment, but the magnetic core half 21.21
Since a ferrite material is used for the auxiliary cores 29 and 29', there is no reduction in the Q value, and a non-magnetic material with high wear resistance such as glass or ceramic may be used for the auxiliary cores 29 and 29'. Other functions and effects are the same as those in the first embodiment, so their explanations will be omitted.

FIG. 3 is a perspective view showing a magnetic head 41 according to a third embodiment of the present invention, in which magnetic core halves 21, 21-- and auxiliary cores 29, 29-- are made of ceramic or the like.
In order to increase the Ql of the magnetic head 41, a ferrite magnetic material is used.

FIG. 4 is a perspective view showing a magnetic head 43 according to a fourth embodiment of the present invention, and shows a magnetic plate 44 made of ferrite material.
A magnetic film 45, such as Sendust, etc. is formed on 44-, and the magnetic core half 21°21- is closed, and the auxiliary core 29
．． This is an example in which a non-magnetic plate made of ceramic or the like is used for 29-.

5(a) to (Q) are schematic explanatory diagrams of the manufacturing process of the magnetic head 20 of the first embodiment of the present invention shown in FIG. Components that are the same as those in the embodiment are denoted by the same reference numerals, and explanations thereof will be omitted.

First, as shown in FIG. 5(a), a block material 50 of a metallic magnetic material made of sendust or the like is prepared and cut along a cutting line 51 to form a pair of block-shaped magnetic core halves 21. 21- is formed, and the width dimension S2 of these magnetic core halves 21.21'' is 1./'2 of the core width of the magnetic head of a household VTR.

Next 1. A joining groove 23.23- is formed on the abutting surfaces of the pair of magnetic core halves 21.21-, and a winding groove 22 is formed on the abutting surface of at least one of the magnetic core halves 21. Further, after forming the track width regulating grooves 27, 27-, the abutting surfaces are mirror-polished, and a non-magnetic film made of, for example, 5i02 is formed at necessary locations on these abutting surfaces.

The steps up to this point are the same as those conventionally used for the magnetic heads of household VTRs, and therefore conventional manufacturing equipment can be used as is without modification.

On the other hand, as shown in Figure (d), a block 52 of ferrite magnetic material is prepared, cut along the cutting line 53, and the cut surface is mirror-polished to form a pair of blocks as shown in Figure (e). A plate-shaped auxiliary core 29°29- is obtained.

The thickness of the auxiliary cores 29 and 29- is appropriately adjusted by the substantial core width S1 of the magnetic head 20. Next, the same figure (f)
As shown in , a winding outer groove 30.30'' is formed on the outer surface of the auxiliary core 29°29-.

Thereafter, mirror polishing is performed on the surfaces 54 and 54-, which will be the adhesive bonding surfaces, and then a thin film of glass for adhesion is formed by sputtering or the like. Next, as shown in FIG. 9 (9), the abutting surfaces of the pair of magnetic core halves 21.21- obtained through the above series of steps are butted against each other, and the inside of the winding groove 22 and the joining groove 23.23- is The magnetic core half body 2 is filled with adhesive glass 24, and the track width regulating groove 27 is filled with mold glass 28.
1.21- is applied with auxiliary cores 29°29' from both sides, pressurized, and heated in an electric furnace to obtain an integrally joined composite block 55.

Next, as shown in FIG. The magnetic head main body 20 of the first embodiment of the invention can be obtained.

As mentioned above, according to the magnetic head manufacturing method of the present invention, a head with a large core width can be manufactured in a process that is almost the same as the conventional magnetic head manufacturing process, so new manufacturing equipment, etc. can be added. Furthermore, since there is no need to significantly change the process details, it is possible to create an efficient magnetic head manufacturing process.

Furthermore, since a glass adhesive can be used to bond the auxiliary core, it is possible to obtain a highly reliable magnetic head.

Also in the manufacturing methods of the second to fourth embodiments, the magnetic core half body 21
．． Since it is clear from the above description that the manufacturing method of 21- can be manufactured using the conventional manufacturing process of the magnetic head main body as it is, the description will be omitted.

(Effects of the Invention) As described above, according to the magnetic head of the present invention, a pair of magnetic core halves are abutted against each other with a non-magnetic gap material interposed between the abutting surfaces to form a magnetic gap on the tape sliding surface. In this magnetic head, an auxiliary core is integrally joined to the abutting surface of the magnetic core halves and to both the half sides so as to form an extension of the tape sliding surface. As a result of being able to form a head with a width larger than the core width of the head, it is possible to manufacture magnetic heads for commercial VTRs, etc. without the need to add special dedicated equipment. Since the same shape as the core half is used, even if the core width of the magnetic head becomes substantially larger, expensive magnetic head material is not consumed unnecessarily (this is advantageous in terms of cost. According to the method for manufacturing a magnetic head according to the present invention, a magnetic head with a large core width can be manufactured using a process that is almost the same as the manufacturing process for conventional magnetic heads, so there is no need to significantly change the process content. This makes it possible to manufacture magnetic heads with high efficiency.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a magnetic head according to a first embodiment of the invention, FIG. 2 is a perspective view showing a magnetic head according to a second embodiment of the invention, and FIG. 3 is a perspective view showing a magnetic head according to a second embodiment of the invention. FIG. 4 is a perspective view showing the magnetic head of the fourth embodiment according to the present invention, and FIGS. 5(a) to (g) are according to the present invention shown in FIG. 1. 6(a) to 6(C) are schematic explanatory diagrams of the manufacturing process of the magnetic head of the first embodiment, and are explanatory diagrams for explaining the relationship between the amount of protrusion of the magnetic head from the magnetic drum and the rounded tip shape. be. 20.40.41.43...Magnetic head body according to the present invention, 21.21-...Magnetic core half, 25...Tape sliding surface, 26...Magnetic gap, 29°29-・
...Auxiliary core, 55...Composite block. Seat map Grass 2 ((ri (b) u), (e)

Claims (4)

[Claims] (1) In a magnetic head in which a pair of magnetic core halves are butted together with a non-magnetic gap material interposed between the abutting surfaces, and a magnetic gap is formed on the tape sliding surface, the abutting surfaces of the magnetic core halves and A magnetic head characterized in that an auxiliary core is integrally joined to both opposite surfaces so as to form an extension of the tape sliding surface. (2) The magnetic head according to claim 1, wherein at least a portion of the magnetic core half is made of a material having a high saturation magnetic flux density, such as a metal magnetic material. (3) The magnetic head according to claim 1, wherein the auxiliary core is made of a ferrite magnetic material, non-magnetic glass, ceramic, or the like. (4) A pair of magnetic core half blocks are integrally joined with a non-magnetic gap material between the abutting surfaces, and a tape sliding surface is provided on both sides of the pair of magnetic core half blocks opposite to the abutting surfaces. A composite block is formed by joining an auxiliary core block to form a part, and after polishing the tip of this composite block to form a tape sliding surface, this composite block is used as a magnetic head consisting of multiple parts. A method for manufacturing a magnetic head, characterized in that it is cut into a main body.