JPS6291002A - Method of adjusting magnetic field of non-reversible transmission element - Google Patents

Abstract

PURPOSE:To obtain the titled element having simple and small-sized structure and to attain fine adjustment of a magnetic field by fixing a magnetic plate having a large diameter than that of a magnet to a face opposite to a ferrite element of the magnet, cutting corners of the magnetic plate so as to adjust the leakage magnetic flux from the magnetic plate. CONSTITUTION:The magnetic flux 33 perpendicular to a plate face coming from the plate face 29a of the magnetic plate 29 and corresponding to that within an outer diameter range of the magnet 20 among the magnetic flux from the magnet 20 becomes parallel effective magnetic flux and gives a magnetic field to ferrite elements 18, 19. A magnetic plate circumference 29b generating leakage magnetic flux is cut off partially as hatched lines to adjust the entire magnetic field fed to the ferrite element via the magnetic plate 29 from the magnet 20 optionally. The surrounding to the magnetic plate 29 is cut off over the entire circumference to change the range and intensity of the effective magnetic flux 33 coming from the surface of the magnetic plate 29 or a part 35 of the ridge of the magnetic plate 29 is notched to adjust the intensity of the magnetic flux generated from the other parts.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention is an isolator or ? -Regarding irreversible transmission elements such as curators, and particularly relating to a method of adjusting a magnetic field applied to a ferrite element housed in a case.

(Prior art) A pair of ferrite elements are disposed close to each other and facing each other in a case, and a permanent magnet is placed on one side of the pair of combined ferrite elements to apply a magnetic field to the ferrite element. In order to change the strength of the magnetic field applied to the ferrite element in isolators and circulators in which lead wires are drawn out from the ferrite element to the input/output terminals of the case, conventionally, magnets are held in an adjustable position to change the strength of the magnetic field applied to the ferrite element. - It has been proposed to adjust the magnetic field by changing the spacing between ferrite elements.

FIG. 4 is a schematic longitudinal sectional view of an isolator with a conventional magnetic field adjustment method. A pair of ferrite elements 18, 19 are mounted inside the case 21 facing each other, and lead wires 26, 27 are drawn out from each ferrite element and connected to input/output terminals of the case. An adjustment screw 30 is screwed into the case 21 at a position facing the ferrite element, and the ferrite element 18.
A magnet 31 that applies a static magnetic field is fixed to 19, and an adjustment screw 30 is operated from outside the case to change the distance between the magnet 31 and the ferrite element, thereby adjusting the magnetic field applied to the ferrite element.

(Problems to be Solved by the Invention) Although the above-mentioned conventional screw type adjustment structure has the advantage that the adjustment screw can be adjusted from the outside with a simple tool after assembly, the structure is complicated and the shape is small. It is larger and requires more parts, and the adjustment range is limited by changing the position of the magnet only by adjusting the screws, making it difficult to accurately and sufficiently adjust the magnetic field.
The drawback was that fine adjustment was not possible. Furthermore, since the magnet is held by a screw mechanism, the position of the magnet is uncertain, making it difficult to obtain stable performance. In the case of a type in which a magnet is fixed, it is very difficult to adjust the magnetic field during assembly.

(Means for Solving the Problems) A magnetic field adjustment method for a non-reciprocal transmission element according to the present invention includes a pair of ferrite elements arranged in a case, and a magnet arranged opposite to the ferrite elements. In an irreversible transmission element that applies a magnetic field,
A magnetic plate having a larger diameter than the magnet is fixed to the surface of the magnet facing the ferrite element, and the corners of the magnetic plate are shaved off to adjust leakage magnetic flux from the magnetic plate.

(Example) Next, the present invention will be described with reference to the drawings.

FIG. 1 is a schematic vertical cross-sectional view of a non-reciprocal transmission element applied when carrying out the method of the present invention.

Further, FIG. 2 is a side view of a magnetic plate and a magnet showing a state in which the magnetic field of the lignet is adjusted by the magnetic field adjustment method according to the present invention, and FIG. 3 is an end view of the magnet according to the present invention as seen from the magnetic plate side. .

A pair of ferrite elements 18, 19 are arranged and fixed in opposition to each other at a small interval in the case 11, and a pair of lead wires 26, 27 are connected from the opposing surfaces of each ferrite element 18, 19.
It is explained in FIG. 4 that the ferrite elements 18 and 19 are pulled out and connected to the input/output terminals 17 and 28 of the case 11, and that a magnet 20 for applying a magnetic field to these ferrite elements 18 and 19 is arranged inside the case. This is the same as the conventional example.

However, in the present invention, as shown in the figure, a magnetic plate 29 (outer diameter D) having a larger diameter than the outside diameter d of the magnet is fixed to the end surface of the magnet 20, that is, the surface facing the ferrite element. The magnetic plate 29 is fixed approximately concentrically to the center of the magnet 20, so that the magnetic plate 29 protrudes outward from the outer periphery of the magnet 20.

As shown in FIG. 2, the magnetic flux generated by the magnet 20 spreads from the plate surface 29a of the magnetic plate 29 to the circumference 29b of the magnetic plate. Among these, the plate surface 29a of the magnetic plate 29
The magnetic flux 33 which is perpendicular to the plate surface and corresponds to the outer diameter range of the magnet 20 becomes a parallel effective magnetic flux and provides a magnetic field to the ferrite elements 18 and 19 (FIG. 1). Magnetic plate 2
The magnetic flux 34 emitted from the vicinity of the periphery of the magnetic flux 34 spreads radially, and part of it is applied to the ferrite element, but the other part does not become an effective magnetic flux to the ferrite element, and becomes so-called leakage flux. Here, the magnetic plate 29't-
The entire magnetic field applied to the ferrite element can be adjusted as desired. As shown in the shaded area in Figure 2, the magnetic plate 2
9 over the entire circumference to change the range and strength of the effective magnetic flux 33 emitted from the surface of the magnetic plate 290, or as shown in FIG. Adjust the strength of the magnetic flux generated from the part.

It is extremely difficult to cut off a part of the magnet by machining due to its material, but the magnetic plate 1 is easy to cut by using, for example, permalloy with high magnetic permeability, and when assembled, the ferrite element 18 can actually be removed. While measuring the magnetic field applied to .19, the magnetic field is adjusted by cutting off a part of the magnetic plate 29 so as to determine the strength of the range 1 where the necessary magnetic flux is applied.

(Effects of the Invention) As explained above, according to the present invention, the magnetic flux applied to the ferrite element of the irreversible transmission element can be arbitrarily adjusted by partially scraping off the magnetic roots, so that the outer diameter of the magnet etc. The dimensions can be made somewhat rough, making it easier to manufacture and assemble the irreversible transmission element. There is no need for a conventional screw-type adjustment mechanism, the structure is simple and compact, and the magnetic field can be finely adjusted, making it possible to obtain a non-reciprocal transmission element with stable performance.

[Brief explanation of drawings]

FIG. 1 is a schematic vertical cross-sectional view of a non-reciprocal transmission element applied to the present invention, FIG. 2 is a side view of a magnet showing a state in which the magnetic field of the magnet is adjusted by the magnetic field adjustment method of the present invention, and FIG. The figure is an end view of the magnet according to the present invention as seen from the magnetic plate side, and FIG. 4 is a longitudinal sectional view of a non-reciprocal transmission element equipped with a conventional magnetic field adjustment mechanism. 11...Case, 20...Magnet,
18.19... Ferrite element. 17.28... Input/output terminal, 29... Magnetic plate. 33... Effective magnetic flux, 34... Leakage magnetic flux.

Claims (1)

[Claims] In a magnetic field adjustment method for an irreversible transmission element in which a pair of ferrite elements are arranged in a case and a magnetic field is applied to the ferrite elements by a magnet arranged opposite to the ferrite elements, a surface of the magnet facing the ferrite elements is A method for adjusting a magnetic field of an irreversible transmission element, characterized by fixing a magnetic plate having a larger diameter than the magnet, and adjusting leakage magnetic flux from the magnetic plate by cutting off corners of the magnetic plate.