JPH0254410A - Compound molded magnetic head of glass and resin and its manufacture - Google Patents

Abstract

PURPOSE:To obtain a magnetic head having superior magnetic characteristic by filling mold glass so as not to be exposed on a tape sliding plane extending from a track width regulation groove to a winding groove, and filling resin in the track width regulation groove so as to cover the glass. CONSTITUTION:The winding groove 15 having an oblique plane 15 is formed on the butting plane of a rectangular block shape magnetic core half body on one side, and it is divided into front and rear butting planes 11a and 11b, and a winding outer groove 16 is formed on a back plane side. The mold glass 18 is provided on the oblique plane 15a, and an elliptic track width regulation groove 17 is formed so as to set track width W equal. Next, a nonmagnetic film 22 made of an SiO2, etc., is filmed on the front butting plane 11a so as to go to around 1/2 of magnetic gap length, and a glass film 19 for joining is formed on the rear butting plane 11b, then, the core half body 11 can be obtained. Next, the track width regulation groove 17 is formed on a half body 12 formed symmetrically to the core half body 11, and both half bodies 11 and 12 are welded by matching the groove 17 with bonding glass 19. Next, the resin 21 is press-fitted in the groove 17, and is hardened and cut at a cutting line, then, a magnetic core main body 20 can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a magnetic head suitable for video tape recorders (VTRs) and the like, and particularly to a highly sensitive magnetic head that does not apply stress near the magnetic gap.

(Prior Art) Conventionally, a magnetic head used in a high frequency band such as a video tape recorder (VTR) and which performs high-speed sliding movement has an M
Ferrite, such as nZn single crystal ferrite, which has excellent high frequency characteristics and is wear resistant, is commonly used as a core material.

FIG. 3 is a front view of the magnetic core body 10 of a conventional magnetic head used in a VTR, etc., and FIG. 3(b) is a top view of FIG. 3(a).

Reference numerals 11 and 12 are magnetic core halves made of, for example, MnZn ferrite single crystal, etc., and both 11 and 12 are abutted with a magnetic gap material made of SiO□ etc. on the abutting surfaces, and a magnetic gap is formed on the tape sliding surface 13. 14 is formed. A winding groove 15 is formed on the abutting surface of at least one of the magnetic core halves 11, and cooperates with a winding outer groove 16 formed on the back side of the one and the other magnetic core halves 11 and 12. A winding (not shown) is applied.

A track width regulating groove 17 is formed between the winding groove 15 and the tape sliding surface 13, and is formed as a pair of arc-shaped grooves on the tape sliding surface 13 sandwiching the magnetic gap 14 from above and below. A track width W is defined between the width regulating grooves 17. A molded glass 18 is melted and filled into the track width regulating groove 17 to reinforce the vicinity of the magnetic gap 14.

(Problem to be Solved by the Invention) The molded glass 18 includes magnetic core halves 11 and 12.
Conventionally, Pb glass-based materials have been used in order to have a coefficient of thermal expansion approximately equal to that of the ferrite materials used in When this sliding movement is performed, the magnetic powder of the magnetic tape adheres to the tape sliding surface 13, inducing spacing loss, reducing the recording and reproducing sensitivity of the VTR, and causing S/N deterioration and reversal phenomena on the playback screen. There was a problem that occurred.

In order to solve these problems, attempts have been made to fill the track width regulating groove 17 with an adhesive instead of molded glass, or to fill the adhesive with a composite resin containing a filler. When epoxy resin or the like is used, about 10% shrinkage occurs when the resin hardens, so the magnetic core half made of ferrite material to be joined 11.
As a result of compressive stress being applied to 12, the properties of the ferrite material, which is structurally sensitive, deteriorate due to this compressive stress, and 1MII
There was a problem that the magnetic head output around Z deteriorated by about 3 dB. In addition, the elasticity Hv of resin is quite soft compared to the others, and if only resin is molded, the magnetic gap 14 will open and close due to the high-speed sliding movement of the magnetic tape and magnetic head during use, so-called. There were problems such as fluctuations in the magnetic gap and a drop in reproduction output of about 3 dB between 1 and 9 MH2.

(Means for Solving the Problems) The present invention has been made to solve the above problems, and includes a pair of magnetic core halves made of a ferrite magnetic material and having a winding groove on the abutting surface of at least one magnetic core half. In a magnetic head in which two magnetic core halves are butted together via a magnetic gap material to form a track width defined by a track width regulating groove in the tape sliding movement, the tape sliding from the track width regulating groove to the winding groove. A composite molded magnetic head made of glass and resin, and a method for manufacturing the same, characterized in that a molded glass is filled so that the surface is not exposed, and the track width regulating groove is filled with resin so as to cover the molded glass. This is what we are trying to provide.

(Embodiment) FIG. 1 is a perspective view showing an embodiment of the magnetic core body 20 of the composite molded magnetic head made of glass and resin according to the present invention, whereas the configuration of the conventional magnetic head 10 shown in FIG. Components that are the same as the elements are given the same reference numerals and explanations will be omitted, and differences between the two will be explained.

In the composite molded magnetic head 20 made of glass and resin according to the present invention, molded glass 18 is filled from the track width regulating groove 17 to the winding groove 15 so as not to be exposed on the tape sliding surface 13. To cover the track width regulating groove 17, resin or
It is filled with a composite resin mixed with fillers to increase hardness.

Further, the thermal expansion coefficient of the molded glass 18 is selected to be approximately 1% smaller than that of ferrite (approximately 1.0×10 −5 ).

19 is a glass film for bonding, and the magnetic core halves 11° 12
The structure is such that the rear abutting surfaces of the two are joined.

With the above-mentioned configuration, even if the resin 21 filled in the track width regulating groove 17 contracts during deflation and exerts compressive stress on the magnetic core body 11.12, the filling from the track width regulating groove 17 to the winding groove 15 is prevented. In contrast, the molded glass 18 imparts tensile stress to the magnetic core halves 11 and 12, so
The above two stresses are canceled out, and no stress is applied to the magnetic core body 11, 12, allowing the ferrite body to exhibit its excellent magnetic properties. In addition, since the magnetic gap 14 is firmly bonded with molded glass 18 or bonding glass 19, only the resin is directly applied to the track width regulating groove 1.
Compared to the structure molded to No. 7, it is held more firmly and the magnetic gap does not open or close during use, and the characteristics are improved by 5 to 6 dB at IMH2 to 9MIIz.

2(a) to 2(i) are explanatory diagrams of the main steps of one embodiment of the magnetic core body of the composite molded magnetic head made of glass and resin of the present invention shown in FIG. 1. I will explain.

First, as shown in FIG. 2(a), a winding groove 15 having an inclined surface 15a is formed on the flat abutting surface of one of the rectangular block-shaped magnetic core halves 12, so that the abutting surface is aligned with the front abutting surface. 11a and a rear abutting surface 11b, and an outer winding groove 16 is formed at a position substantially symmetrical to the winding groove 15 on the back side of the abutting surface.

Next, as shown in FIG. 2B, the inclined surface 15 of the winding groove 15
Place the molded glass 1 on the same plane as the abutting surface.
8 is provided by melting, for example, by melting the molded glass 18 into the winding groove 15, forming a rectangular groove by a known cutting means, and grinding the entire abutting surface to remove the excess molded glass. Obtained by removing .

Next, as shown in FIG. 1C, a plurality of approximately elliptical track width regulating grooves 17 are formed from the front abutment 11a to the winding groove 15. At this time, adjacent track width regulating grooves 17 are formed.
7 are alternately formed so that the intervals are equal to the track width W.

Next, as shown in the same figure (d), S* such as sputtering is applied.
A magnetic gap 1 is formed on the front abutment surface 11a using a forming means.
Non-magnetic v! such as SiO2 for the formation of 4! 22 to approximately 1/2 of the length of the magnetic gap 14, and a bonding glass film 19 is formed on the rear abutment surface 11b to have approximately the same thickness as the non-magnetic WA 22, thereby reducing the One block-shaped magnetic core half 11 is obtained. Next, as shown in FIG. 3(e), the other block-shaped magnetic core half 12 having a substantially symmetrical shape with the block-shaped one magnetic core half 11 is prepared, and the abutment surface 12a
A winding outer groove 16 is formed on the back side of the wire.

Next, as shown in FIG. 3(f), when the block-shaped one and other magnetic core halves 11 and 12 are abutted, the track width regulating groove is formed in one block-shaped magnetic core half 11. As shown in FIG.
Non-magnetic l! such as Sio2 on top! 22 and the magnetic gap 1
The other half of the magnetic core 12 is obtained before being butted.

Next, as shown in FIG.
After abutting them so that they face each other in just the right amount, the adhesive glass 19 and the molded glass 18 are bonded using a heating furnace or other means.
is heated and the two are joined together.

Next, as shown in FIG. By cutting according to 23, a magnetic core body 20 of a composite molded magnetic head made of glass and resin according to the present invention as shown in FIG. 1 before R polishing is obtained.

(Effects of the Invention) As described above, the composite molded magnetic head made of glass and resin according to the present invention is made of a ferrite magnetic material,
A pair of magnetic core halves having a wound n-groove on the abutting surface of at least one of the magnetic core halves are butted together via a magnetic gap material, and a track width defined by a track width regulating groove is formed on the tape sliding surface. In this magnetic head, a molded glass is filled from the track width regulating groove to the winding groove so as not to be exposed on the tape sliding surface, and the molded glass is covered with a molded glass for the track width! Since the groove II is filled with resin, stress is not applied to the magnetic core body made of ferrite magnetism, and the excellent magnetic properties inherent to ferrite can be exhibited. Further, since the magnetic gap can be firmly held by molded glass or the like, the magnetic gap does not open or close, and the characteristics do not deteriorate due to this, making it possible to provide a highly reliable magnetic head.

Further, according to the manufacturing method of the present invention, the composite mold magnetic head made of glass and resin of the present invention can be easily manufactured.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing one embodiment of a magnetic core body of a composite molded magnetic head made of glass and resin according to the present invention, and FIGS. 2(a) to (1) show the glass and resin of the present invention shown in FIG. FIG. 3 is a front view of the magnetic core body of a conventional magnetic head used in a VTR or the like. 11.12...Magnetic core half, 13...Tape sliding surface, 14...Magnetic gap, 15...Winding groove, 16
...Winding outer groove, 17...Track width regulation groove, 18.
...Mold glass, 19...Glass for bonding, 20.
...Magnetic core body, 21...Resin or composite resin, 22
...Nonmagnetic film, 23... Cutting line. Figure 4b (C) 6゜Details of the amendment, page 10, line 10, ``approximately 1/2'' is deleted and the date of October 1989 is removed.

Claims (2)

[Claims] (1) A pair of magnetic core halves made of ferrite magnetic material and having a winding groove on the abutting surface of at least one of the magnetic core halves are butted together via a magnetic gap material, and a track width regulating groove is formed on the tape sliding surface. In a magnetic head having a defined track width, molded glass is filled from the track width regulating groove to the winding groove so as not to be exposed on the tape sliding surface, and the molded glass is filled with the molded glass so as to cover the molded glass. A composite molded magnetic head made of glass and resin, characterized in that track width regulating grooves are filled with resin. (2) A step of preparing a pair of block-shaped magnetic core halves made of ferrite material and forming a winding groove on the abutting surface of at least one block-shaped magnetic core half; a step of forming molded glass in the winding grooves of the body; a step of forming substantially elliptical track width regulating grooves in the pair of magnetic core halves; and a step of forming the pair of block-shaped magnetic cores obtained in the step. A process of forming a non-magnetic film and a bonding glass at different positions on the abutting surfaces of the halves, and a process of abutting the pair of block-shaped magnetic core halves obtained in the above process and then heating them to bond the glass. and a step of press-fitting a resin into the track width regulating groove of the bonded block obtained in the above step, curing it, and then cutting it into magnetic core halves having a predetermined shape. A method for manufacturing a composite mold magnetic head using resin.