JPS62264407A - Gap forming jig - Google Patents

Abstract

PURPOSE:To pressurize a magnetic core with a regulated and stable pressing force, by selecting a ceramics material as the material of the flat spring of a gap forming jig. CONSTITUTION:A gap forming core holding main body 1 consists of a pair of magnetic head cores 21 and 22 to form a gap, a presser plate 2, a flat spring 3 made of a zirconia, a pressurizing screw 4 to pressurize the flat spring, and a bonding glass 23 to weld the magnetic head cores 21 and 22. In a gap forming process, the relative positions of the magnetic head cores 21 and 22 are fixed, and a prescribed pressure is applied by the pressurizing screw 4. At such a time, a deformed flat spring 3 generates a resiliency, and continues to pressurize the magnetic head cores 21 and 22 through the presser plate 2. The magnetic head cores, after being heated and held at an electric furnace to bond them by a molten glass at 500 deg.C for thirty minutes, are annealed. In this way, it is possible to fully pressurize the magnetic head core with a regulated and stable pressing force even at a high temperature area where the glass is melted.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a gap forming jig used for aligning a pair of magnetic held cores to form a magnetic gap therebetween.

Conventional technology Forming the gears of a magnetic head involves fixing the mutual positions of the magnetic radial cores, applying pressure to bring the facing surfaces of the magnetic radial cores into close contact, and bonding and fixing the cores with glass molten at high temperature. That's true. Conventionally, gear forming jigs have been used for this purpose.

An example of a conventional gap forming jig is shown in Figure 2 (al (bl
This is shown and explained below. In Fig. 2, 1 is a gap forming core holding body, 2 is a pressing plate, 13 is a plate spring made of a special alloy, 4 is a pressure screw for pressurizing the plate spring, and 21 and 22 are used to form a gap. The magnetic head core 23 is a bonding glass for welding the magnetic head cores together.

The gap forming process will be explained. Magnetic helad core 21, 2
After determining the mutual positions of the springs 1 and 2, the temporary spring 1 is tightened with the pressure screw 4.
3 to deform the temporary spring 13.

The reaction force of the leaf spring 13 due to the deformation is transmitted to the magnetic rad core 21.22 via the pressing plate 2, and the gap surfaces of both magnetic rad cores 21.22 are brought into close contact. Generally, a glass material is used to secure the gap space and reinforce the gap, so the punching glass 23 is heated by heating the gap forming jig 5 including the magnetic head core in an electric furnace or the like.
) Glue the stone drum head cores 21 and 22,
The desired gap length is obtained.

Problems to be Solved by the Invention Since the anti-In force of the temporary spring 13 of the gap forming jig is greatly reduced in a high temperature range, there has been a problem in that variations in gap length accuracy become large and yields deteriorate. This was a big problem, especially in narrow gears such as those used in video applications, and in rear gears.

Means for Solving the Problems The technical means of the present invention for solving the above problems is to use a gear forming jig in which a ceramic material is used as the plate spring material.

Working Ceramic leaf springs have a small drop in the resultant force even in high temperature ranges, and can provide a stable and constant pressing force against temperature changes. Therefore, even in high temperature ranges where glass melts, they can press the fn air head core in a constant and stable manner. It can be pressurized with pressure.

EXAMPLE Hereinafter, an example of the gap forming jig of the present invention will be described based on the drawings.

[Example 1] In FIG. 2, 1 is a gear, a core holding body 21
．． 22 is a pair of magnetic hemlock cores that are intended to form a gap, 2 is a pressing plate, 3 is a zirconia plate spring, 4 is a pressure screw that presses the temporary spring, and 23 is a magnetic head core 21
This is bonding glass for welding 22.

In the gap forming step, the mutual positions of the magnetic head cores 21 and 22 are fixed, and a predetermined pressure is applied by the pressure screw 4. The deformed leaf spring 3 at this time generates an anti-10 force, and the pressure plate 2
The magnetic head cores 21 and 22 are continuously pressurized through the magnetic head cores 21 and 22. In order to bond the magnetic head core 2.3 with the molten glass, it was heated and held at 500° C. for 30 minutes in an electric furnace, and then slowly cooled.

[Example 2] A magnetic head was prepared in the same manner as in Example 1 except that the temporary spring 3 was made of magnesia material.

Figure 3 shows the relationship between the temperature change and the reaction force of the leaf spring materials of Examples 1 and 2. From the figure, the results of Example 1 and Example 2 are compared to the conventionally used special alloy leaf springs. It is clear that the leaf spring material according to the present invention in No. 2 is superior in that the drop in the reverse ↑θ force is small under high temperatures.

Further, Table 1 shows the relationship between the type of plate spring material and the gap length.

Note that for the measurement of the gap length, development was used in which the reproduction output decreases due to gap loss as the reproduction gap length of the head approaches the shortest wavelength of the recorded reproduction signal.

For the target gap length value of 0.25 μm, the average value of Example 1゜2 is 0.25 μm, and the average value of the conventional example is 0.35 μm.
It can be seen that Examples 1 and 2 are superior. Moreover, the minimum and maximum values of gap length variation are 0.2 to 0.3 μm in Example 1 and 0.2 to 0.0 μm in Example 2.
35 pm, which is 0.15 to 0.6 of the conventional example.
It can be seen that it is smaller than μm.

Effects of the Invention Ceramic leaf springs have a smaller drop in repulsive force than metal leaf springs even in high temperature ranges, and are stable against temperature changes and can obtain a constant pressing force. Even in this case, the magnetic head core can be pressed with a sufficiently constant and stable pressing force.

[Brief explanation of drawings]

FIG. 1 (a) is a front view of the gap forming jig when a magnetic core is attached to the magnetic head in which a gap is to be formed in an embodiment of the present invention, (b is a plan view,
Figure 2 (ill) (bl is a front view of the gap forming jig when a conventional magnetic head core for gap formation is to be installed, (a) is a front view, (tl) is a plan view, and Figure 3 is a diagram of the first embodiment. It is a graph showing the relationship between the temperature change and the reaction ↑Ω force of the temporary spring material No. 2. 1... Gap forming core holding body, 2...
...Press plate, 3...Ceramic leaf spring, 4.
...Pressure screw, 21...Magnetic head core, 22...Magnetic head core, 23...
Bonding glass, 13...Special metal leaf spring. Name of agent: Patent attorney Toshio Nakao, 1st LQ
〜－〇沫

Claims (2)

[Claims] (1) A gap forming jig consisting of a gap forming core holding body, a pressing plate, a plate spring, and a pressure screw, characterized in that the plate spring is made of a ceramic material. (2) The gap forming jig according to claim (1), wherein the material of the plate spring is at least one of zirconia, magnesia, and thoria.