JPH0113386Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a variable inductance element that can smoothly change the inductance of a pot-shaped magnetic core. This invention relates to a variable inductance element that smoothly changes inductance by moving the inductance.

A variable inductance element using this type of pot-shaped magnetic core is known, for example, as described in Japanese Utility Model Publication No. 57-8169.

The variable inductance element described in Japanese Utility Model Publication No. 57-8169 has the following configuration. The first is
As shown in FIG. 1, two pot-shaped magnetic cores 1, 1 having a through hole 3 in the center of the magnetic leg 2 are integrally formed facing each other, and the open end of the through hole 3 of the pot-shaped magnetic core 1 Fix the collar part 5 ₁ to the recess provided in with adhesive,
A flanged nut 5 is provided in which a nut portion 5 ₂ on the flange portion 5 ₁ is inserted into the through hole 3 . In addition, the through hole 3 has a screw portion 4 ₁ from the open end opposite to the flanged nut 5.
An adjustable magnetic core 4 with screws inserted is provided.
Furthermore, a coil 6 is inserted into the gap 6a between the inner and outer magnetic legs of the pot-shaped magnetic cores 1,1.

The above-mentioned adjustment magnetic core 4 with screws is shown in the exploded perspective view, the second
As shown in the figure, a synthetic resin screw portion 4 _{1 is provided at the lower end of a rod-shaped ferrite magnetic core 4 2 ,} and a male thread is cut on the outer periphery of the screw portion 4 ₁ to attach the flanged nut 5 described above. The nut part 5 ₂ is configured to move up and down within the through hole 3 by screwing into the female thread 5 a on the inner wall surface and rotating the adjusting magnetic core 4 with screws. Further, the nut portion 5 of the flanged nut 5
A plurality of small protrusions 5b are formed on the outer peripheral surface of ₂ in the same direction as the central axis of the through hole 3, so that the nut portion 5a can be inserted into the through hole 3 without eccentricity.

According to the variable inductance element of this configuration, by rotating the adjusting magnetic core 4 with screws to the left or right, the screw portions are screwed together with the female threads 5a of the nut portions 5 _{and 2} of the flanged nuts 5 and ₄ , respectively. The adjustable magnetic core 4 moves upward and downward within the through hole 3, changing the magnetic resistance of the gap between the pot-shaped magnetic cores 1, 1, and changing the inductance value.
The variable inductance characteristic of the variable inductance element of this configuration depends on the accuracy with which the flanged nut 5 is fixed. That is, if the center axis of the flanged nut 5 is fixed so as to accurately match the center axis of the through hole 3 of the pot-shaped magnetic cores 1, 1, the rate of change in inductance versus rotation speed of the adjusting magnetic core 4 with screws, In other words, the inductance variable characteristics change smoothly and have little fluctuation.

However, the male thread of the screw part 4 ₁ of the adjustable magnetic core 4 with screws and the female thread 5 of the nut part 5 ₁ of the flanged nut 5
If the pitch shapes of a do not match, or during installation work, when inserting the flanged nut 5 into the through hole 3, the small protrusion 5b on the outer periphery of the nut portion ₅₂ may It was crushed and the pot-shaped magnetic core 1,1
The flanged nut 5 may be inserted eccentrically into the through hole 3. For this reason, the rate of change in inductance of the variable inductance element shown in FIGS. 1 and 2 has a drawback that the inductance characteristic changes rapidly as shown in FIG. 8A.

Further, the second variable inductance element described in Japanese Utility Model Publication No. 57-8169 is a through hole provided in the center of the magnetic legs 2 of the pot-shaped magnetic cores 1 and 1, as shown in FIGS. 4 and 5. A recess 3 ₁ having a tapered periphery is provided at one end of the hole 3 , and a tapered outer circumferential surface 5 3 _and a dish-shaped stepped portion are provided in the recess 3 ₁ to correspond to the inner circumferential surface of the recess 3 ₁ . Except for the structure in which the flange 5 _{1 having a flange 5 4 and} the flange nut 8 inserted into the through hole 3 and the nut 5 ₂ protruding from the flange 5 ₁ are fixed with adhesive, the above-mentioned conventionally known variables are used. It has the same structure as the inductance element. That is, the adjustable magnetic core 4 with screws is inserted into the through hole 3, a female thread is formed on the inner surface of the nut portion 5 ₂ of the flanged nut 8, and the screw portion 4 ₁
It can be moved upward or downward within the through hole 3 by screwing and rotating the male screw.

As described above, the outer circumferential surface of the flange portion 5 ₁ of the flanged nut 8 shown in FIGS. 4 and 5 is formed to fit into the recess 3 ₁ , and the nut portion 5 ₂ is provided with a female thread. At the same time, the screw part 4 ₁ of the adjusting magnetic core with screw is formed so as to be able to rotate by being screwed into the female thread of the nut part 5 ₂ .

Further, a coil 6 is inserted into a gap 6a between the inner and outer magnetic legs of the magnetic leg 2.

The above-described flanged nut 8 is inserted into the through hole 3 until the flanged portion 5 ₁ fits into the recessed portion 3 ₁ , and then is fixed in the recessed portion 3 ₁ with an adhesive. The recess 3 ₁ that fixes the flange 5 ₁ not only serves as an adhesive reservoir, but also serves as a place to store the flange 5 ₁ .

In the variable inductance element having the structure shown in FIGS. 4 and 5, the outer circumferential surface of the flange of the flanged nut is tapered to correspond to the inner circumferential surface of the recess formed at the open end of the through hole of the pot-shaped magnetic core. Furthermore, since both are tightly fixed with adhesive so that their central axes coincide, when screwing the adjustment magnetic core 4 with screws into the female thread of the nut portion 5 ₂ of the flanged nut 8, it is necessary to adjust the eccentricity. becomes less.

However, the variable inductance element of this structure (shown in FIGS. 4 and 5)
In order to reduce the eccentric movement of the adjusting magnetic core 4 with screws that moves inside, the length of the nut part ₅₂ of the flanged nut 8 increases by increasing the distance moved by the nut part ₅₂ of the flanged nut 8. As a result, the lower tip of the adjusting magnetic core 4 with screws hits the upper part of the nut part ₅₂ , and cannot enter the through hole 3 any further.
It becomes impossible to obtain a wide range of inductance change rates. Also, Figures 1 to 2
As in the case of the variable inductance element shown in the figure, the pitch and shape of the female thread formed in the nut part 5 ₂ of the flanged nut 8 and the male thread formed in the screw part 4 ₁ of the adjustable magnetic core with screws are different. If they are not completely matched, the adjusting magnetic core 4 with screws will not fit through the through hole 3.
Since it moves upward or downward while being eccentric with respect to the inductance, the fluctuation in the rate of change in inductance becomes large.

This invention was made in order to eliminate such drawbacks of conventional variable inductance elements, and allows the adjusting magnetic core with screws to move toward the flanged nut side within the through hole of the pot-shaped magnetic core without being eccentric over a wide range. The present invention aims to provide a variable inductance element that is movable, has little fluctuation, and can obtain a sufficiently large rate of change in inductance.

Embodiments of this invention will be described below with reference to FIGS. 6 to 7 and FIG. 8B.

6 and 7 are a cross-sectional view and an exploded perspective view of a main part of a variable inductance element according to an embodiment of the present invention.

Reference numerals 9 and 9 in FIG. 6 are a pair of upper and lower pot-shaped magnetic cores made of ferrite, each having a through hole 11 in the center of the magnetic leg 10, and a recess 12 formed at the open end of this through hole 11. .

Reference numeral 13 denotes an adjustment magnetic core with screws that is inserted into the through hole 11 of the pot-shaped magnetic core 9, and is provided with a magnetic core 14 made of ferrite and a screw portion 15 with a male thread cut on the outer periphery at the bottom of the magnetic core 14. .

16 is the screw portion 15 of the adjustment magnetic core 13 with screws.
A cylindrical nut portion 17 that is inserted into the through hole 11 of the magnetic core 9 and is a flanged nut made of synthetic resin that is screwed into the nut.
and a flange 18 that is inserted into the recess 12.

The outer diameter of the cylindrical nut portion 17 is approximately equal to the inner diameter of the through hole 11 of the pot-shaped magnetic core 9, and is relatively long. Furthermore, the nut part 17
has an inner diameter approximately equal to the outer diameter of the adjusting magnetic core 13 with screws on the upper inner surface of the adjusting magnetic core 13 with screws.
Up inside the nut part 17 along the central axis of the through hole 11,
A hollow space 17a is provided so that it can be slidably moved downward. Also, nut part 1
Inside under the air gap 17a of No. 7, there is an adjusting magnetic core 13 with screws.
When the adjusting magnetic core 13 with screws is rotated, the female screws 17b of the screw portion 15 and the nut portion 17 are screwed together, and the adjusting magnetic core 13 with screws is connected to the flanged nut. 16 voids 17a
It is structured so that you can be guided inside.

In the above embodiment, an example in which the void 17a on the inner surface of the nut portion 17 of the flanged nut 16 is formed by thinning has been described. It may be something you have done.

In addition, 22 in FIG. 7 is a driver groove formed in the head of the adjusting magnetic core 13 with screws, and 23 is a gap 9 between the inner magnetic legs and outer magnetic legs of the pot-shaped magnetic cores 9, 9.
24 is a bobbin of the coil 23.

Further, the nut portion 17 of the flanged nut 16 is
Although the nut part 17 is formed to be fitted into the through hole 11 of the pot-shaped magnetic core 9, the outer diameter of the nut part 17 is made slightly smaller than the inner diameter of the through hole 11, and a plurality of small protrusions 17c are formed on the outer periphery of the nut part 17. may be provided.

When the variable inductance element is configured as described above, the adjusting magnetic core 13 with screws inserted into the through hole 11 of the pot-shaped adjusting magnetic core 9 can be slidably moved within the gap 17a of the nut portion 17 of the flanged nut 16. I can do it. Furthermore, by increasing the depth of the air gap 17a, the magnetic core 14 of the adjusting magnetic core 13 with screws is guided inside the air gap 17a along the central axis of the through hole 11, and then the tip of the screw part 15 at the bottom of the magnetic core 15 is brought into contact with the flange. Since it is moved within the flanged nut 16 by screwing into the female thread 17b of the bolt nut 16 and screwing together the screw portion 15 and the female screw portion 17b, eccentricity caused by the screwing between the female screw portion 17b and the screw portion 15 can be reduced.

Therefore, it is possible to obtain a characteristic diagram in which the rate of change in inductance due to the rotation of the adjusting magnetic core 13 with screws changes smoothly as shown in FIG. 8B.

As is clear from the above description, the variable inductance element according to this invention has a pot-shaped magnetic core having a through hole in the center of the magnetic leg, a flange fixed to the open end of the through hole, and a nut portion on the upper surface of the flange. A flanged nut inserted into the through hole; an adjustable magnetic core with screws inserted into the through hole, having a magnetic core disposed in the upper part, and a screw part provided in the lower part of the magnetic core to be screwed into the nut part of the flanged nut; In the variable inductance element, the outer diameter of the nut part of the flanged nut is formed approximately equal to the inner diameter of the through hole of the pot-shaped magnetic core, and the upper part of the nut part is formed with an inner diameter approximately equal to the outer diameter of the adjustable magnetic core with screws. A gap is provided in which the adjusting magnetic core with screws can freely move up and down, and a female thread is provided at the bottom of the gap to engage with the screw portion of the adjusting magnetic core with screws, so that the adjusting magnetic core with screws has a pot-shaped shape. Inside the magnetic hole, along the central axis of the hole,
Since the variable inductance element can accurately slide over a long distance, the inductance change rate of the variable inductance element can be varied over a wide range with little variation.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a conventional variable inductance element, Figure 2 is a perspective view of the main parts of Figure 1, Figure 3 is
B is an explanatory diagram showing the state of attachment of the magnetic core and nut;
The figure is a sectional view of another conventional variable inductance element, FIG. 5 is a perspective view of the main part of FIG. 1, FIG. 6 is a sectional view of an embodiment of this invention, and FIG. The exploded perspective view of the nut and FIGS. 8A and 8B are characteristic diagrams of variable characteristics of a conventional variable inductance element. 1, 9... pot-shaped magnetic core, 2, 10... magnetic leg,
3, 11... Through hole, 4, 13... Adjustable magnetic core with screw, 4 ₁ , 15... Screw part of adjustable magnetic core with screw, 4
₂ , 14...Magnetic core of adjustable magnetic core with screws, 5, 8, 1
6... Flammed nut, 17a... Nut part void of the flanged nut, 17b... Female thread in the nut part of the flanged nut.

Claims (1)

[Scope of utility model registration request] a pot-shaped magnetic core with a through hole in the center of the magnetic leg; a flanged nut with a flange fixed to the open end of the through hole, and a nut on the upper surface of the flange inserted into the through hole; In a variable inductance element consisting of a screw-equipped adjustable magnetic core, which is inserted into a screw and has a magnetic core in the upper part and a screw part in the lower part of the core that screws into the nut part of the flanged nut, the outer diameter of the nut part of the flanged nut is is formed to be approximately equal to the inner diameter of the through hole of the pot-shaped magnetic core, and has an inner diameter approximately equal to the outer diameter of the adjusting magnetic core with screws, and is provided with a gap in which the magnetic core with screws can freely move up and down. . A variable inductance element, characterized in that a female thread is provided in the lower part of the gap to be screwed into the screw part of the adjusting magnetic core with screws.