JPS6346886Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to the structure of a magnetic head using a metal magnetic material such as sendust.

In recent years, in order to increase the density of magnetic recording, efforts have been made to develop magnetic recording/reproducing heads using metallic magnetic materials such as sendust, which has a higher saturation magnetic flux density than conventional ferrite. Generally, the manufacturing method for heads is to abut and join two core blocks that are long in the thickness direction so that the winding holes that separate the front and rear goat parts are formed inside the blocks, and then slice them in the thickness direction and form them. has been adopted. For ferrite-based materials, glass is effective as a welding material for joining, and the material itself has strong mechanical strength, so the above method is effective, but glass is not suitable for metallic magnetic materials, especially sendust-based materials. is not suitable as a welding material because it does not penetrate well between the cores and the bonding force between them is weak because of poor wettability and compatibility. For this reason, there are no known welding materials other than brazing materials such as silver solder that are effective for metal magnetic materials, and as shown in FIG.
A method is adopted in which a brazing material 4 is inserted and heated and welded. However, because metal magnetic materials such as sendust have strong mechanical tenacity, the front gap forming surface tends to be plastically deformed and the gap length tends to widen when the core is sliced during the manufacturing process or when the tape is actually slid. . especially
In the case of a head with a track width of several tens of microns, such as a video head for a VTR, this problem is acute, and it is required to provide a joint near the front gear. Generally, a deposited film of SiO ₂ or the like is formed on the front gap to define the gap length, but it does not have bonding properties. For this reason, a structure has been proposed in which the periphery of the winding hole 5 is filled with brazing material 6 and the periphery of the winding hole is also bonded. However, with this method, a diffused layer of brazing material may ooze out from the front gap side of the winding hole to the gap interface, increasing the effective gap length, or in extreme cases, precipitates may appear at the interface near the gap or voids may be formed. I had a problem. The size of this diffusion layer can be reduced to some extent by controlling the manufacturing process, but if surface diffusion and grain boundary diffusion are included, it has been confirmed that it expands from several hundred microns to several microns, even considering the gap length (1 micron or less). This has a great influence on the characteristics of the head.

The present invention provides a structure that improves the above-mentioned problems by devising the joining means in the winding holes, and will be explained below with reference to the drawings. FIG. 3 shows an embodiment of the present invention. In the figure, 10 and 11 are metallic materials (for example, sendust)
The abutting surfaces of each core half are formed so as to provide a winding hole 12 and a welding material filling hole 13 when the core halves are combined. Silver solder 1 is attached to a guide 15 made of a non-magnetic material such as phosphor bronze or beryllium copper on the side surface of the winding hole except for a certain area l from the lower end of the front gap 14.
6, thereby reinforcing the joint strength of each core half. In FIG. 4, which is an enlarged view of the portion 17 in FIG. 3, a region 18 shows a diffusion layer formed during welding of the silver solder 16 and subsequent heat treatment. The guide 15 to which the silver solder 16 is attached has elasticity at least before heat treatment,
When this is installed in the winding hole 12, its position can be defined. Then, when the core halves abutted with the front gap 14 facing upward are pressurized and heated, silver solder that can flow is filled between the core side surface and the guide, and other than that, for example, in a certain area near the front gap 14 side. It is regulated to prevent it from flowing into the country. On the other hand, a conventional welding material 19 is installed in the filling hole 13, thereby performing the main joining of each core half.

FIG. 5 corresponds to FIG. 4 of another embodiment of the present invention. As shown in the figure, the coupling member 20 of this embodiment is constituted by a guide 22 having an annular cross section and having a silver solder 21 coated on the outer periphery so as to be inscribed in the winding hole 12. If the material of this guide is phosphor bronze, its springiness is completely removed in the state after welding as shown in the figure, but when it is inserted into the winding hole 12, its springiness is pressed against the side of the hole. Granted.

As explained above, the present invention abuts two core halves made of metallic magnetic materials, defines a front gear between the abutting surfaces, and defines a lower end of the front gear, and further defines an opposing surface that widens downward from the lower end. In the magnetic head having a winding hole, a silver solder is provided between the side surfaces forming the winding hole beyond a certain area from the lower end to connect each of the core halves. Therefore, substantially all the way to the bottom end of the front gap can be used as a magnetic head without degrading the magnetic properties due to the silver solder diffusion layer. Also, in the part beyond a certain area from the lower end of the front gear,
Since a connecting member is provided to join each half of the core that makes up the magnetic head, the strength of the joint near the front gear can be increased compared to the conventional magnetic head made of metal magnetic material, which is joined only at the rear goat. Therefore, even if the core thickness is reduced to accommodate a narrow track width, there is no risk of the gap length becoming mechanically widened. In addition, when these core halves were joined together using silver solder, the joining was done at a certain distance from the front gap, so the diffusion layer penetrated into the front gap and deteriorated the magnetic properties. There is no risk of causing

Furthermore, since the magnetic head of the present invention has a core made of a metallic magnetic material, it is suitable for densely recording and reproducing high frequency signals such as television signals on so-called metal tapes whose magnetic layer contains a magnetic material with a large coercive force. Applicable.

[Brief explanation of the drawing]

FIGS. 1 and 2 are block diagrams of a conventional magnetic head. FIG. 3 is a schematic configuration diagram of the magnetic head of the present invention, and FIG. 4 is a partially enlarged view of FIG. 3. FIG. 5 is a schematic configuration diagram of another embodiment. 10, 11... Core half, 12... Winding hole, 1
6...Joining member, 15...Guide.

Claims (1)

[Scope of utility model registration request] Two core halves made of a metallic magnetic material are brought into contact with each other, and a front gap is provided between the abutting surfaces thereof, and a winding hole is provided which defines a lower end of the front gap and has opposing surfaces that widen further downward from the lower end, In the magnetic head in which the two core halves are joined by silver solder, a guide for positioning the silver solder on a portion of the side surface forming the winding hole of each core half, away from the lower end, is provided for the winding wire. A magnetic head, characterized in that the front gap is provided in a hole, and a gap is formed near the lower end in the winding hole to prevent silver solder from being present in the front gap.