JP2001177309A5 - - Google Patents

Description

0012
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the irreversible circuit element and the method for manufacturing the irreversible circuit element according to the present invention will be described with reference to an embodiment. FIG. 1 is an exploded perspective view showing the overall configuration of the isolator according to the present invention, FIG. 2 is a perspective view of a lower yoke having an integral structure with a resin case, and FIGS. It is a cross-sectional view, and FIG. 5 is a perspective view of a hoop-shaped lower yoke. As shown in FIG. 1, in the isolator according to the present invention, a resin case 7 provided with an external terminal and a lower case 12 are integrated, and three central conductors are mutually insulated by a magnetic material in a recess of the resin case. The assembled assembly 20, the capacitors 8, 9, 10 and the resistance element 11 are mounted on a predetermined portion by applying cream solder, and the upper case and the lower case in which the permanent magnets are arranged are fitted to each other. .. The recess for arranging the assembly 20 is formed deeper than the thickness of the assembly 20. The metal material constituting the lower case 12 having an integral structure with the resin case is at least one selected from SPCC, 42 alloy, and Fe—Co alloy, and these metal materials are cold-rolled to about 100 to 300 μm. Or it is hot rolled. Further, a metal or alloy containing at least one of silver, copper, gold, and aluminum on its surface has a high electrical resistivity of 5.5 μΩcm or less, preferably 3.0 μΩcm, and more preferably 1.8 μΩcm or less. It forms a metal film. The film thickness at this time is 0.5 to 25 μm, preferably 0.5 to 10 μm, and more preferably 1 to 8 μm. The assembly 20, the capacitors 8, 9, 10 and the resistance element 11 are mounted on the lower yoke, and the metal film enhances the signal transmission efficiency, suppresses mutual interference with the outside, and reduces the loss. Therefore, unlike the conventional isolator, the electrical characteristics do not deteriorate even if the resin case is not formed by using the conductor plate. It is preferable to use 42 alloy as the metal material because it has excellent oxidation resistance. Further, since the upper and lower yokes are used as a part of the magnetic circuit, it is desirable to use SPCC or Fe-Co alloy having excellent magnetic characteristics, and the composition of the Fe-Co alloy is specifically mass%. Co: 49, V: 2, C: ≤0.015, Si: ≤0.10, Mn: ≤0.15, the balance Fe and unavoidable impurities, respectively. The plate material of this alloy can be produced as an ultrathin plate having a thickness of about 100 μm, and usually has a maximum magnetic permeability of 15,000 and a saturation magnetic flux density of 2.25 Tesla. Here, Co is selected from 40 to 60% from the correlation between the frequency band and the magnetic characteristics, but about 50% is desirable, and V is added to improve cold workability, but on the other hand, it affects the magnetic characteristics. Therefore, it should be 5% or less, and 2% is desirable to ensure workability. If this Fe—Co alloy is used for the yoke, magnetic flux leakage in the magnetic circuit is suppressed necessaryly and sufficiently even if the thickness of the yoke is reduced, so that the isolator can be further made thinner and smaller.