JPS63222309A - Production of magnetic head - Google Patents

Abstract

PURPOSE:To improve reproduction output by subjecting a magnetic core body formed by cutting a block core to a heat treatment at a specific temp. and to permit easy reading of a lifetime size by annihilating the stripe pattern of glass. CONSTITUTION:The magnetic core body 23 formed by cutting the block core in a process for producing a ferrite magnetic head is subjected to the heat treatment by using an electric furnace or the like. The annealing temp. is set at the temp. from the transfer point of molded glass MG up to the fluid temp. Removal of the strains exerted to the ferrite magnetic material and the molded glass at the time of working such as end polishing and slicing is thereby permitted, by which the reproduction output is improved and the fluctuation is decreased. The strip pattern of the molded glass is annihilated by the annealing so that the easy reading of the size at the time of setting the lifetime size (t) is permitted.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of manufacturing a magnetic head used in a magnetic recording/reproducing device, particularly a video tape recorder (hereinafter referred to as VTR).

(Prior art) In magnetic heads used in household VTRs, etc.,
Since the maximum frequency used is a relatively high frequency of several MH2, a ferrite magnetic material that has a high resistivity, low eddy current loss, and high wear resistance is generally used as the magnetic core. Structurally, in order to increase the cross-sectional area and strength of the magnetic core, the thickness of the magnetic core body is made thicker than the required track width, and the actual track width of the magnetic core formed on the tape sliding surface is The track width is determined by the distance between the tips of U-shaped track width regulating grooves that are formed between both ends of the tape sliding surface, and the track width is formed by melting and filling these track width regulating grooves with molded glass. The magnetic core is reinforced to increase strength and wear resistance.

Figures 4 <a> to (j) are explanatory diagrams showing the manufacturing process of a conventionally commonly seen ferrite magnetic head having a molded glass on the tape sliding surface, and the manufacturing process will be explained below with reference to the figures. .

First, as shown in the figure (a), a rectangular block 10 made of a ferrite magnetic material is prepared, and then, as shown in the figure (b), the abutment surface 11 is aligned along the longitudinal direction of the block 10.
An outer groove 12 for winding is machined on the opposite side. Next, as shown in the same figure (C), a pair of blocks 10° 10' with outer grooves 12 for winding processed are prepared, and these blocks 10.1
A notch groove 1 is provided along the longitudinal direction at the end of the abutting surface 11 of 0'.
3, then the abutting surface 1 of the other block 10'
A winding groove 14 is formed in 1. Next, as shown in FIG. 10(d), a U-shaped track width regulating groove 15 is formed so as to span the notch groove 13 formed in the abutment surface 11 of the block 10.10'. The track width regulating groove 15 formed in the other block 10' is formed so as to communicate with the winding groove 14.

Next, as shown in FIG. 2(e), an adhesive glass 'a lf[16] is formed on the abutting surface 11 of one block 10 by an I'll forming means such as sputtering, and the other block 10 is A thin film 17 made of 5if2 or the like is formed by the same means on the abutting surface 11 of the track width regulating groove 15 forming portion of ', so as to have a desired magnetic gap length. Next, as shown in the same figure (f), one block 10° and 10' are butted against each other and fixed with a jig, etc., and then the notch groove 13 and the track width regulating groove 15 are melted and filled with molded glass MG. Block core 18 is then formed by joining blocks 10 and 10' together. Next, as shown in FIG.
etc., and by polishing the tip of the block core 18, a life dimension t is formed, and a track width defined by the distance S between the magnetic gap 21 and the track width regulating groove 15.15 is formed on the tape sliding surface 20. form a recording track with Next, as shown in the same figure (h), block core 1
8 along the cutting line 22 passing through the track width regulating groove 15 to obtain a plurality of magnetic cores 23 having predetermined dimensions and shapes.
However, rather than cutting it off completely, it is sliced so that a portion of the posterior surface 24 remains.

Next, as shown in FIG. 1151 (1), the tape sliding surface 2o is wrapped with a tape 25 in order to remove chipping burrs and the like generated in the slicing process. Next, as shown in FIG. 4(j), by slicing the rear surface 24, a single magnetic rad core body 23 can be obtained. FIG. 5 is a perspective view of the magnetic helad core body obtained by the manufacturing process shown in FIG. 4.

(Problems to be Solved) The magnetic head manufactured by the manufacturing method described above has the following problems.

(1) Although the reproduction output value of the obtained magnetic head could not be said to be insufficient, the characteristic values varied widely and were not stable.

('2J Due to the slicing process shown in FIG. 4(if), a striped pattern is generated on the mold glass MG surface exposed on the side surface 26 of the magnetic core body 23, as shown in FIG. 5.
There was a problem in that when measuring the life dimension t, the dimension was difficult to read and the workability was extremely poor.

(Means for Solving the Problems) The present invention has been made to solve the above problems, and includes forming a block core having a magnetic gap and a molded glass portion at a position corresponding to the sliding portion of the recording medium. A method for manufacturing a magnetic head, characterized in that the block core is cut into magnetic core bodies having a predetermined shape, and then the magnetic core bodies are heat-treated at m degrees between the transition point and the flow temperature of the molded glass. This is what we provide.

(Example) In the first example of the manufacturing method according to the present invention, substantially the same steps as those in the conventional magnetic head manufacturing method shown in FIGS. 4(a) to (j) are used. Description of similar steps will be omitted, and only different steps will be explained.

The difference is that the tape wrapping process shown in FIG. 4 (1) is omitted, and the rear surface 24 is sliced to obtain a single magnetic core body 23 as shown in FIG. The point is that the main body 23 is annealed using an electric furnace or the like.

The annealing temperature is set at a temperature between the transition point tg of the molded glass melted and filled into the track width regulating groove 15 and the flow temperature tr.

The transition point here refers to the temperature at which strain disappears from the glass when heat is applied to the glass to increase its salinity, and when η is the viscosity of the glass (poise), log η-13,3...
(1) It refers to the temperature tQ at which the glass has a viscosity coefficient η (poise) shown by the equation (1).

In addition, the flow temperature tf refers to the temperature at which the glass melts when heat is applied to the glass and the temperature is raised, and log η-5
(2) It is defined as the temperature tf at which the glass has a viscosity coefficient η (poise) expressed by the equation ('2J).In this example, the concentration is 150°C lower than the flow temperature. Good results were obtained by performing annealing for about 1 hour.

As described above, according to the manufacturing method of the present invention, by annealing the magnetic core body cut into single pieces at a predetermined temperature, the ferrite magnetic material and molded glass can be added during processing such as tip polishing and core slicing. It has been found that as a result of being able to remove the distortion caused by the ferrite magnetic material, the original characteristics of the ferrite magnetic material are revealed, and the reproduction output of the magnetic head is improved and the variation in the output is reduced. FIG. 3 is a graph showing the relationship between the recording voltage and the reproduction output obtained before and after annealing the magnetic core body 23, and the horizontal axis shows the recording voltage (
(2) The vertical axis represents the reproduction output (mV). As is clear from FIG. 3, the high frequency (5 MHz) indicates that the reproduction output is more likely to increase due to annealing.

In addition, at an appropriate annealing temperature, the molded glass softens and chipping chips etc. that occur on the glass part disappear.
The chances of damaging the magnetic tape during use are reduced, improving reliability.

FIG. 1 is an enlarged photograph of the tape sliding surface of the magnetic head body after annealing in the magnetic head manufacturing method of the present invention, and FIG. 2 is an explanatory view of the photograph shown in FIG. 1. 6th
The figure is an enlarged photograph of the tape sliding surface of the magnetic head main body before annealing, and FIG. 7 is an explanatory diagram of FIG. 6.

As is clear from a comparison between FIG. 1 and FIG. 6, chipping is seen in the etched portion of the molded glass MG melted and filled into the track width regulating groove 15 in FIG. has disappeared. Furthermore, it can be seen that the striped pattern of the molded glass MG seen in FIG. 6 has completely disappeared in FIG.

For the above reasons, according to the method of manufacturing a magnetic head according to the present invention, the tape wrapping step shown in FIG. magnetic gap 21
The life dimension t of can be easily read.

Next, a second embodiment of the manufacturing method according to the present invention will be described, but since it is substantially the same as the manufacturing process of the first embodiment, only the different points will be explained.

The difference is that in the first embodiment, annealing is performed after cutting the magnetic core body 23 into individual pieces, but in the second embodiment, annealing is performed after core slicing as shown in FIG. 4 1), and then The magnetic core body 23 is separated into individual pieces by slicing the rear surface 24. The main functions and effects are completely the same as those of the first embodiment, so they will be omitted, but the unique effect of the second embodiment is that the magnetic core body 23 that is the object of heat treatment is made up of a plurality of magnetic core bodies 23. This has the effect of making the work easier because it can be handled as

In the above first and second embodiments, an example was explained in which a ferrite magnetic material was used for the magnetic core, but it is not limited to a ferrite magnetic material, but may also be a gold-aminous material such as sendust, or
It can also be applied to a magnetic head made of a composite material of a ferrite magnetic material and a metal magnetic material, and its application range is wide-ranging.

In addition, the applicable devices are not limited to VTRs, but also audio, D
Needless to say, it can be widely applied to ATs, digital heads, etc.

(Effects of the Invention) As described above, according to the method of manufacturing a magnetic head of the first embodiment of the present invention, a block core having a magnetic gap and a molded glass portion is formed at a position corresponding to the recording medium sliding portion, and this After cutting the block core into a magnetic core body having a predetermined shape, this magnetic core body was heat-treated at a temperature between the transition point of the mold glass and the flow temperature. 1) Strain was removed from the magnetic material and the mold glass. To be saved,
The magnetic permeability μ of the magnetic material is restored, and the reproduction output of the magnetic head is improved.

2) Furthermore, since the original characteristics of the magnetic material are exhibited, variations in characteristics such as reproduction output are reduced, making it possible to supply stable products.

3) Under an appropriate annealing concentration, the mold glass softens and chips and chips in the glass part disappear, making it possible to omit the tape-wrapping process to remove chipping chips, etc., reducing the number of steps. I can do it.

4) Furthermore, since the striped pattern of the molded glass on the side surface of the core caused by core slicing disappears by annealing, the life dimension can be easily read, improving work efficiency.

5) By annealing the glass for 7 times in an appropriate atmosphere, the quality of the glass can be changed and the abrasion resistance can be improved.

There are other effects.

Further, according to the method of manufacturing a magnetic head of the second embodiment of the present invention, a block core having a magnetic gap and a molded glass portion is formed at a position corresponding to the recording medium sliding portion, and this block core is separated. A plurality of magnetic core bodies having a predetermined shape are formed, and these magnetic core bodies are heat-treated at a temperature between the transition point of the molded glass and the flow temperature. Since the magnetic core body is separated into individual pieces, the magnetic core body to be heat treated can be handled as a block of magnetic core bodies made up of a plurality of pieces, which has the effect of improving work efficiency.

[Brief explanation of the drawing]

FIG. 1 is an enlarged photograph of the tape sliding movement of the magnetic head body after annealing in the magnetic head manufacturing method i according to the present invention, FIG. 2 is an explanatory diagram of the photograph shown in FIG. 1, and FIG. 3 is an enlarged photograph of the magnetic core body Graphs showing the relationship between the recording voltage and the reproduction output obtained before and after annealing, Figures 4(a) to (l) are of a conventional ferrite magnetic head having molded glass on the tape sliding surface. An explanatory diagram showing the manufacturing process, FIG. 5 is a perspective view of the magnetic core body obtained by the manufacturing process shown in FIG. 4, FIG. 6 is an enlarged photograph of the tape sliding movement of the magnetic head body before annealing, and FIG. 7 is an explanatory diagram of Fig. 6. MG: molded glass, 15: track width regulating groove, 18: block core, 20: tape sliding surface, 21: magnetic gap, 23・・・Magnetic core body.Drawings of Jyōsaku v1, all 2 (e) <f), ()) Figure 3 Procedures Amendment (Method) June 1988/Date

Claims (2)

[Claims] (1) Form a block core having a magnetic gap and a molded glass part at a position corresponding to the recording medium sliding part, cut this block core into a magnetic core body having a predetermined shape, and then cut the block core into a magnetic core body having a predetermined shape. A method of manufacturing a magnetic head, characterized in that the magnetic head is heat-treated at a concentration between a transition point and a fluid concentration. (2) A block core having a magnetic gap and a molded glass part is formed at a position corresponding to the recording medium sliding part, and this block core is sliced without separation to form a magnetic core body consisting of a plurality of pieces having a predetermined shape. A method of manufacturing a magnetic head, comprising: heat-treating these magnetic core bodies at a temperature between the transition point of the molded glass and the flow temperature, and then cutting the plurality of magnetic core bodies into individual pieces.