JPH1012433A - Magnetic circuit having temperature compensation structure and non-reciprocal circuit element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic circuit having a temperature compensation structure wherein a space for arranging magnetic compensating steel is made as small as possible, form is simple, working is easy, cost is low, and magnetic flux distribution of a magnet is not disturbed. SOLUTION: This magnetic circuit consists of magnets 1-1, 1-2, magnetic material 2 to be magnetized by the magnets, a magnetic yoke 3 which effectively passes magnetic flux generated by the magnets, and magnetic shunt steel 4-2 performing temperature compensation of magnetic flux. The magnetic shunt steel 4-2 having a hole 4-1 smaller than the magnets is arranged between the magnet 1-2 and the magnetic material 2. By arbitrarily selecting the forms of the magnetic shunt steel 4-2 an its hole 4-1, magnetic flux distribution is made symmetric, and characteristics of a magnetic circuit is stabilized. By the structure wherein the magnetic shunt steel 4-2 is sandwiched between the magnet and the magnetic material, a magnetic circuit having a temperature compensation structure excellent in utilization factor of space can be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a temperature compensation structure for a magnetic circuit using permanent magnets and electromagnets.

[0002]

2. Description of the Related Art A conventional embodiment will be described with reference to FIGS. In general, as shown in FIG. 4, the magnetic circuit includes a magnet 1 for generating a magnetic flux, a magnetic body 2 magnetized by the magnet 1, and a magnetic yoke 3 for efficiently magnetizing the magnetic body 2. A permanent magnet or an electromagnet is used for the magnet 1, and iron, a coil, or a ferrite is used for the magnetic body 2. As the magnetic yoke, soft iron, pure iron, permalloy, or the like having high magnetic permeability and low magnetic resistance is used. The magnetic body 2 exhibits its function by being magnetized by the magnet 1.

FIG. 5 is a diagram in which the magnetic circuit of FIG. 4 is replaced with an equivalent electric circuit. In FIG. 5, the magnetic flux Φ can be expressed as a current source, and the resistance Rm can be expressed as a magnetic resistance when the magnetic body 2 is magnetized. Generally, magnets and magnetic materials have a negative temperature coefficient.When the temperature rises, the magnetic flux generated by the magnet decreases, and the magnetic resistance of the magnetic material also increases, so the degree of magnetization of the magnetic material decreases from room temperature. I do. Conversely, when the temperature decreases, the magnetic flux of the magnet increases, and the magnetic resistance of the magnetic body also decreases, so that the degree of magnetization of the magnetic body increases. In any case, the function of the magnetic material is reduced by the temperature change. In particular, when a low-cost magnet, such as a ferrite magnet or a soft iron material, is used, the temperature dependency is very large, and the function of the magnetic material is impaired.

FIG. 6 shows a magnetic circuit having a conventional temperature compensation structure devised to make the change in magnetization of a magnetic material due to temperature constant. That is, if the magnetic shunt steel 4 having a positive magnetic coefficient of magnetic resistance is arranged in parallel with the magnetic body 2 in a magnetic circuit, the temperature change of the magnet 1 and the temperature change of the magnetic body 2 can be canceled. FIG. 7 is a diagram showing the magnetic circuit of FIG. 6 as an equivalent electric circuit similarly to FIG. In the same figure, if the magnetic flux passing through the magnetic body 2 is Φm and the magnetic flux passing through the magnetic shunt steel 4 is Φs,

[0005]

Φ = Φm + Φs Differentiation by temperature T

[0006]

DΦ / dT = dΦm / dT + dΦs / dT

[0007]

## EQU3 ## Since dΦs / dT> 0 and dΦm / dT <0,

[0008]

## EQU4 ## If the temperature coefficient of the magnetic shunt steel 4 is selected so that dΦs / dT = −dΦm / dT,

[0009]

## EQU5 ## dΦ / dT = 0 can be satisfied. As a modification of the conventional magnetic circuit as shown in FIG. 6, a magnetic shunt steel 4 is wound around the magnet 1 as shown in FIG.
As shown in FIG. 9, there is a type in which a part of the magnet 1 is installed in a U-shape.

[0010]

However, in the conventional magnetic circuit having the temperature compensation structure, the space utilization factor and the shape of the magnetic shunt steel are complicated and expensive, and the magnetic flux distribution applied to the magnetic material is asymmetric. There is a drawback that the function of the magnetic circuit is impaired.

Accordingly, the present invention provides a magnetic circuit having a temperature compensation structure that minimizes the space in which the magnetic shunt steel is installed, is easy to machine with a simple shape, is inexpensive, and has a symmetrical magnetic flux distribution of the magnet. An object is to provide a reversible circuit element.

[0012]

In order to achieve the above object, the present invention provides a magnet, a magnetic body magnetized by the magnet, a magnetic yoke for efficiently passing a magnetic flux provided by the magnet, and In a magnetic circuit made of a magnetic shunt steel for performing temperature compensation, a magnetic shunt steel having a hole smaller in size than the magnet is provided between the magnet and the magnetic body. With this configuration, if the shapes of the magnetic shunt steel and the holes of the magnetic shunt steel are arbitrarily selected, the magnetic flux distribution becomes symmetric and the characteristics of the magnetic circuit are stabilized.
Further, a magnetic circuit having a temperature compensation structure with a high space utilization ratio can be provided from the structure in which the magnetic shunt steel is sandwiched between the magnet and the magnetic body.

According to another aspect of the present invention, there is provided a non-reciprocal circuit device in which a magnetic material, an electrode and a magnet are arranged in layers, wherein a magnetic shunt steel having a hole smaller than the magnet is provided between the magnet and the magnetic material. ing. With this structure, the circuit characteristics are stable,
A non-reciprocal circuit device having a space-saving temperature compensation structure can be provided.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a first embodiment of the present invention.
Will be described. The magnet 1-1 has a hole 4-1 smaller than the area of the magnet 1-1 on one side, and a magnetizing steel 4-2 slightly larger than the outer shape of the magnet 1-1 is provided. This magnetic shunt steel 4-2
Of the magnetic material 2 between the surface not in contact with the magnet 1-1 and the magnet 1-2
And the magnets 1-1 and 1-2 are connected by the magnetic yoke 3 to form a closed magnetic circuit. This closed magnetic circuit applies a magnetic flux to the magnetic body 2 through the magnetic yoke 3. The main magnetic flux Φm to the magnetic body 2 is supplied through the space of the hole formed in the magnetic shunt steel 4-2, and the magnetic flux Φs passing through the magnetic shunt steel 4-2.
Is the magnet 1 through the space from the edge 4-3 of the magnetic shunt steel 4-2.
Return to -1. In this way, a parallel magnetic circuit is formed,
The temperature coefficient of the magnetic circuit is canceled.

In the embodiment of the present invention, the magnets 1-1, 1
-2, the magnetizing steel 4-2, and the hole 4-1 of the magnetizing steel use an example in which a square is used, but other shapes may be used, and the present invention can be applied to a case where there are a plurality of holes. In addition, the magnetic shunting steel does not necessarily have to have only holes, and the present invention can be applied to a magnetic deflecting steel having a partially missing shape. Furthermore, even when the magnetic shunt steel is formed by stacking a plurality of magnetic shunt steels having different temperature coefficients,
The present invention is applicable.

With this configuration, unlike the conventional magnetic circuit, the structure of the magnetic shunt steel 4-2 can be easily formed by pressing a magnetic shunt steel plate or the like. In particular, by making the holes formed in the magnetic shunt steel moderate, the ratio of the magnetic flux Φm and Φs and the outer shape of the magnetic shunt steel can be minimized. The characteristics of the magnetic circuit can be optimized without disturbance. Furthermore, by stacking a plurality of magnetic shunt steels having different temperature coefficients, it is possible to obtain an optimum magnetic shunt steel that cancels the temperature coefficient of the magnetic material by combining the temperature coefficients.

A second embodiment of the present invention will be described with reference to FIG. FIGS. 2A and 2B show an embodiment in which the present invention is applied to a microwave isolator. Although a closed magnetic circuit is not formed through the magnetic yoke, a ring-shaped magnetic shunt steel 4-4 is sandwiched between the magnet 1 and the ferrite substrate 5, and a circuit pattern 8 and a terminator 9 are formed on the ferrite substrate 5. This is a structure in which the carrier plate is laminated with the lowermost layer. A spacer 7 is laminated between the magnetic shunt steel 4-4 and the ferrite substrate 5, but this adjusts the magnetic force of the magnet 1 by the height of the spacer 7, and does not affect the configuration of the magnetic circuit. A non-magnetic material having a magnetic permeability of 1 is used. The carrier plate 6 has the same function as the magnetic yoke, and is made of soft iron or the like that efficiently passes magnetic flux.

The magnetic flux Φm from the magnet 1 through the ferrite substrate 5 as a magnetic material through the hole 4-5 of the magnetic shunt steel 4-4 returns from the magnetic yoke 6 to the other pole of the magnet 1 through the space, and at the same time, from the magnet 1 The magnetic flux Φs passing through the magnetic steel 4-4 returns from the space to the other pole of the magnet 1 through the edge 4-6 of the magnetic shunt steel 4-4.

The characteristics of the second embodiment of the present invention will be described with reference to FIG. 3 (a) and 3 (b) are magnetic shunt steels 4-4, respectively.
FIG. 4 is a diagram showing temperature characteristics of an isolator without a magnetic field and an isolator using a magnetic shunt steel 4-4. In an isolator without magnetic shunt steel, the isolation, input / output reflection loss, and insertion loss characteristics greatly differ depending on the temperature difference. In comparison, the isolator using the magnetic shunt steel 4-4 of the present invention has a small difference in temperature characteristics due to a difference in temperature. As described above, it can be understood that the characteristics of the present invention due to the temperature change are compensated.

In the second embodiment of the present invention, the magnetic shunt steel 4-4 has a ring shape, but the present invention can be applied to other shapes. Although the isolator has been described, the present invention can be applied to a non-reciprocal circuit device such as a circulator having a similar structure. Further, the present invention can be applied to a magnetic shunt steel in which a plurality of magnetic shunt steels having different temperature coefficients are laminated.

From this configuration, the magnetic shunt steel 4 disposed on the magnet 1
Since -4 is a circular ring, a magnetic field is uniformly applied to the ferrite substrate 5 from the magnet surface so that unnecessary mode spurious does not occur in the isolator characteristics. Further, the degree of temperature compensation can be optimized by the size, thickness, and outer diameter of the hole of the magnetic shunt steel. Furthermore, by stacking a plurality of magnetic shunt steels having different temperature coefficients, it is possible to obtain an optimum magnetic shunt steel that cancels the temperature coefficient of the magnetic material by combining the temperature coefficients.

[0022]

According to the present invention, it is possible to obtain a magnetic circuit temperature compensation effect with a simple and inexpensive structure without requiring unnecessary space.

[Brief description of the drawings]

FIG. 1 shows a perspective view of the present invention.

FIG. 2 shows a perspective view and a side sectional view of the present invention applied to a microwave isolator.

FIG. 3 is a graph showing temperature characteristics of isolation and insertion loss of an isolator before and after temperature compensation.

FIG. 4 is a perspective view showing a conventional magnetic circuit.

FIG. 5 is a diagram showing an equivalent electric circuit of a conventional magnetic circuit.

FIG. 6 is a perspective view showing a conventional temperature compensation structure.

FIG. 7 is a diagram showing an equivalent electric circuit of a conventional temperature compensation structure.

FIG. 8 is a perspective view showing another conventional temperature compensation structure.

FIG. 9 is a perspective view showing another conventional temperature compensation structure.

[Description of sign]

 DESCRIPTION OF SYMBOLS 1 ... Magnet 2 ... Magnetic body 3 ... Magnetic yoke 4 ... Magnetic shunting steel 5 ... Ferrite substrate 6 ... Carrier plate 7 ... Spacer 8 ... Pattern 9 ... Terminator

Claims (8)

[Claims] 1. A magnet comprising: a magnet; a magnetic body magnetized by the magnet; a magnetic yoke for passing a magnetic flux provided by the magnet through the magnetic body; and a magnetic shunt steel for performing temperature compensation of the magnetic flux. A magnetic circuit having a temperature compensation structure, wherein the magnetic shunt steel is disposed between a magnet and a magnetic body, and has a hole smaller in size than the magnet. 2. A magnet inscribed in a circle centered on the center axis of the magnet,
The magnetic circuit having a temperature compensation structure according to claim 1, further comprising a magnetic shunt steel having a hole whose center point is the same as the center point of the circle. 3. A magnet inscribed in a circle centered on the center axis of the magnet,
The magnetic circuit having a temperature compensation structure according to claim 1, further comprising a magnetic shunt steel having a shape whose center point is the same as the center point of the circle. 4. A magnetic circuit having a temperature compensation structure according to claim 1, wherein said magnetic shunt steel is made of two or more kinds of magnetic shunt steels having different temperature coefficients. 5. A non-reciprocal circuit device in which a magnetic material, a circuit pattern of a predetermined shape, and a magnet are arranged in layers, wherein a magnetic shunt having a hole smaller than the magnet is provided between the magnet and the magnetic material. A non-reciprocal circuit device comprising steel. 6. A magnet inscribed in a circle centered on the center axis of the magnet,
6. The non-reciprocal circuit device according to claim 5, further comprising a magnetic shunt steel having a hole whose center point is the same as the center point of the circle. 7. Inscribed in a circle centered on the center axis of the magnet,
6. The non-reciprocal circuit device according to claim 5, further comprising a magnetic shunt steel having a shape whose center point is the same as the center point of the circle. 8. The non-reciprocal circuit device according to claim 5, wherein said magnetic shunt steel is made of two or more kinds of magnetic shunt steels having different temperature coefficients.