JPH01293605A - Choke coil - Google Patents

Abstract

PURPOSE:To easily adjust inductance by a method wherein the distance between the surface of an I type core facing an E type opening end surface and a planar surface including the opening end surface is formed differently in the longitudinal direction of the I type core and the I type core is moved in the longitudinal direction. CONSTITUTION:An I type core 2 is positioned in such a way that a recess 2a is positioned in an E type core 1 and seals the opening end surface of the core 1 with a spacer 3 included between them. Therefore, distances of the surface of the core 2 facing the opening end surface of the core 1 between the planar surface including the opening end surface differ in the longitudinal direction of the core 2. In the assembly of a choke coil, the core 2 is moved in a longitudinal direction while inductance is being observed, and when a desired inductance value is reached, cores 1, 2 are fixed by an adhesive. This makes it possible to easily adjust inductance by moving the core 2 in a longitudinal direction.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a choke coil used in a ballast or the like.

[Prior Art] This type of cheek coil is generally of the type shown in Fig. 13, which is called an El-type core. That is, an E-shaped core A and an I-shaped core B made of soft magnetic material such as soft ferrite are formed into a square shape, and a bobbin D around which a coil C is wound is inserted into the central leg piece of the E-shaped core A. . Reference numeral E denotes a spacer made of heat-resistant resin, and an appropriate number of spacers are inserted and held between the cores A and B in order to obtain a predetermined inductance.

Further, as another conventional example, the one shown in FIG. 14 has been proposed. In other words, in this case, the E-shaped core is replaced with a C-shaped (sometimes called U-shaped) core F, a bobbin D wound with a coil C is inserted into the ■-shaped core B, and an appropriate number of spacers G, G are inserted. is separated into left and right.

In order to obtain a predetermined inductance, conventional choke coils such as those described above prepare a plurality of spacers and adjust them while changing the laminated thickness of these spacers.

[Problems to be Solved by the Invention] As mentioned above, conventional choke coils are roughly assembled by inserting a plurality of spacers, and the laminated thickness is changed while measuring the inductance, so it is difficult to adjust to obtain a predetermined inductance. The process is troublesome, and the inductance that is adjusted through such an adjustment process can only be obtained in stages due to the thickness of the spacer.

The present invention has been made in view of the above reasons, and its purpose is to provide a choke coil whose inductance can be easily adjusted and whose inductance can be changed continuously.

[Means for Solving the Problems] In order to achieve the above object, the choke coil of the present invention includes an E-type or C-type core made of a soft magnetic material, and a structure in which the open end surface of the E-type or C-type core is closed. The summer type core to be placed and E
a spacer inserted between the type or C-type core and the I-type core;
A choke coil consisting of a coil wound around any of the above cores, wherein the distance between the surface of the summer core facing the open end surface of the E-type or C-type core and the flat surface including the open end surface is The summer core is formed differently in the longitudinal direction.

More specifically, at least one recess is formed in a corresponding portion of the type 1 core that corresponds to the open end of the E or C type core.

Further, the summer core is formed such that the surface of the summer core facing the opening end surface is inclined in the longitudinal direction. In this case, it may be one piece with an inclined surface spanning the entire length of the summer core, or
The number of inclined surfaces corresponding to the opening end surfaces may be formed.

[Function] In the choke coil of the present invention, the summer core is moved in the longitudinal direction while measuring the inductance before the assembly is completed, that is, in the rough assembly state, and when the required inductance is reached, the summer core is moved with the spacer inserted. Fix both cores with adhesive. In other words, by moving the summer core in the longitudinal direction, the magnetic resistance of the magnetic path formed by both cores changes, thereby changing the inductance. Therefore, the inductance can be easily adjusted by moving the summer core in the longitudinal direction, and the inductance is
It can be changed continuously.

(Example) Hereinafter, an example of the present invention will be described based on FIGS. 1 to 12.

1 to 3 show a first embodiment.

Reference numeral 1 denotes an E-type core, which is made of a soft magnetic material such as Mn-Zn ferrite (effective magnetic permeability: 3000). A central leg piece 1a and left and right leg pieces 1b make up the E type.

1b are equal in height, so each opening end surface is on the same plane (
on a flat surface).

2 is a summer type core, which is made of the same soft magnetic material as the E type core. The summer type core 2 is longer than the width of the E-type core 1 by about 1 minute longer than the width of the left and right leg pieces 1b, 1b, and a recess 2a is formed in the corresponding part of either of the left and right leg pieces 1b, lb, that is, at one end in the longitudinal direction. It has been done.

A spacer 3 is made of heat-resistant resin and has a length approximately equal to the width of the E-shaped core 1.

A coil 4 is wound around a coil frame 5 and inserted into the central leg piece 1a.

The summer core 2 is arranged so that the recess 2a is located on the E-type core 1 side, and the spacer 3 is inserted to close the open end surface of the E-type core 1. Therefore, the distance between the surface of the summer core 2 facing the open end surface of the E-shaped core 1 and the flat surface including the open end surface differs in the longitudinal direction of the summer core 2.

When assembling the choke coil, the summer core 2 is moved in the longitudinal direction while measuring the inductance, and when the desired inductance value is reached, both cores 1.2 are fixed with adhesive or the like.

In this example, when the desired inductance was 200 μH, each dimension (unit: mm) in FIG. 2 was set as follows.

For E-type core 1, width a = 28, center leg 1a width b -7,5, left and right leg 1b width c -4,1, total height of each leg d -17, actual height of each leg. e -12,5, thickness f-
1) For summer type core 2, total length g = 32.7, recess 2
a length h-4,7, recess 2a depth l-0,15, thickness j
-3゜7, width -1)゜For spacer 3, total length 1-28, thickness m = 1.6
, width n-1)° and the coil 4 was made of 45S.

As shown in FIG. 2, when the concave portion 2a is located outside the width of the E-shaped core I, the magnetic resistance of the magnetic path becomes the minimum, and the inductance becomes 205 μH. On the other hand, in a state where the recess 2a is located so as to substantially overlap the leg 1b of the E-shaped core 1 as shown in FIG. 3, the magnetic resistance of the magnetic path is maximum and the inductance is 195 μH. In other words, the choke coil of this embodiment has an adjustment range of 10 μH, and the inductance can be changed continuously within that range.

Incidentally, since the variation in inductance of currently available EI type choke coils is generally about ±3%, the choke coil of the present invention can provide an extremely highly accurate inductance.

FIG. 4 shows a modification of the first embodiment, and only the ■-shaped core is different. The I-type core 2 of this product includes each leg piece 1a of the E-type core 1,
lb, all corresponding parts of lb, that is, in addition to one end in the longitudinal direction, a total of three recesses 2a near the intermediate part and the other end,
2b and 2c are formed. In this modification, since the amount of change in the magnetic resistance of the magnetic path can be larger than that in the previous embodiment, the adjustment range of the inductance can also be increased. however,
(2) Since the amount of change in inductance with respect to the amount of movement of the type core 2 becomes large, the ease of fine adjustment is slightly inferior.

FIG. 5 shows a second embodiment.

A C-shaped core 21 is made of a soft magnetic material such as Mn-Zn ferrite (effective magnetic permeability 3000). Left and right leg pieces 21b, 21b forming a C shape
The heights of the openings are equal, and therefore the opening end faces are on the same plane (flat surface).

Reference numeral 22 denotes an I-type core, which is made of the same soft magnetic material as the C-type core. The type core 22 is longer than the width of the C-type core 21 by about one of the left and right leg pieces 21b, 21b, and has a recess in a corresponding part of either of the left and right leg pieces 21b, 21b, that is, at one end in the longitudinal direction. 22a is formed.

A spacer 23 is made of heat-resistant resin and has a size corresponding to the opening end surfaces of the left and right leg pieces 21b, 21b of the C-shaped core.

24 is a coil, which is wound around a coil frame 25 to form a ■-shaped core 2.
2 is inserted. Note that since the coil frame 25 is fixedly disposed at the time of inductance adjustment, the inner hole 25a of the coil frame 25 is
is made sufficiently larger than the I-type core 22.

The I-shaped core 22 is arranged so that the recess 22a is located on the C-shaped core 21 side, and the spacer 23 is inserted to close the open end surface of the C-shaped core 21. Therefore, the I-shaped core 22 facing the open end surface of the C-shaped core 21
The distance between the surface of the I-type core 2 and the flat surface including the opening end surface is
The two become different in the longitudinal direction.

The assembly of the choke coil, including inductance adjustment, and the operation and effects are substantially the same as in the first embodiment.

FIG. 6 shows a modification of the second embodiment, where only the I-shaped core is different. The I-type core 22 of this product is connected to each leg piece 2 of the C-type core 21.
1b and 21b, that is, in addition to one end in the longitudinal direction, a total of two recesses 22a are provided near the other end.
22b is formed. In this modification, the amount of change in the magnetic resistance of the magnetic path is larger than that in the previous embodiment, so
The inductance adjustment range can also be widened. However, r
Since the amount of change in inductance with respect to the amount of movement of the mold core 2 increases, the ease of fine adjustment is slightly inferior.

Figures 7 to 9 show the third embodiment, which is different from the first embodiment.
Only the mold core and spacer are different.

■The type core 32 has left and right leg pieces 1b from the width of the E type core 1,
The left and right leg pieces 1b are about 1 lb long.

The E-type core 1 is made so that the thickness of the corresponding part of 1b is continuously different.
The side thereof is formed into an inclined surface 32a.

The spacer 33 has an inclined surface 3 which is approximately the same size as the ■-shaped core 32 in plan view and is inclined approximately equally to the I-shaped core 32.
3a, and are adhesively fixed to the I-shaped core 32 so that when stacked on the I-shaped core 32, their thickness becomes uniform in the longitudinal direction.

The ■-shaped core 32 is arranged so that the inclined surface 32a is located on the E-shaped core 1 side, and the spacer 33 is inserted to close the open end surface of the E-shaped core 1. Therefore, The distance between the I-shaped core 320 surface facing the open end surface of the E-shaped core 1 and the flat surface including the open end surface differs in the longitudinal direction of the summer core 2.

Assembly of the choke coil including inductance adjustment is performed in the same manner as in the first embodiment.

In this example, when the desired inductance is 200 μH, the dimensions of the summer core 32 and spacer 33 (first place is all) in FIG. 8 are set as follows.

The E-type core 1 is the same as in the first embodiment.

For the summer core 32, the maximum thickness is p-4,3, and the minimum thickness q=3.1°.For the spacer 33, the maximum thickness is r-2,2, and the minimum thickness is s-1°.Inductance adjustment of this The range is substantially the same as in the first embodiment.

FIG. 10 shows a modification of the third embodiment, which differs only in the summer core and spacer. This summer type core 32 is the E type core 1
all corresponding parts of each leg piece 1a, lb, lb, ie a total of three inclined surfaces 32b, 32c in the longitudinal direction.

32d is formed. The spacer 33 also has an inclined surface 33 corresponding to the inclined surfaces 32b, 32c, and 32d.
b, 33c.

33d is formed. In this modification, since the amount of change in the magnetic resistance of the magnetic path can be larger than that in the previous embodiment, the adjustment range of the inductance can also be increased.

However, since the amount of change in inductance relative to the amount of movement of the summer core 32 is large, the ease of fine adjustment is slightly inferior.

Figure 1) shows a fourth embodiment, which differs from the second embodiment only in the summer core and spacer.

The summer core 42 is made to be longer than the width of the C-shaped core 21 by at least one of the left and right leg pieces 21b, 21b, and the thickness of the corresponding parts of the left and right leg pieces 1b, lb are continuously different.
The E-type core 1 side is formed into an inclined surface 42a. Further, the spacer 43 also has an inclined surface 43a corresponding to the above-mentioned inclined surface 42a.
is formed.

The assembly of the choke coil, including inductance adjustment, and the functions and effects are substantially the same as in the second embodiment.

FIG. 12 shows a modification of the fourth embodiment, which differs only in the summer core and spacer. This summer type core 42 is the C type core 2
A total of two inclined surfaces 42b and 42C are formed in all the corresponding parts of each of the leg pieces 21b and 21b, that is, in the longitudinal direction. The spacer 43 also includes the side slope 42b,
Slanted surfaces 43b and 43c corresponding to 42c are formed.

In this modification, since the amount of change in the magnetic resistance of the magnetic path can be larger than that in the previous embodiment, the adjustment range of the inductance can also be increased. However, since the amount of change in inductance with respect to the amount of movement of the summer core 2 increases, the ease of fine adjustment is slightly inferior.

[Effects of the Invention] Since the choke coil of the present invention is configured as described above, the summer core is moved in the longitudinal direction while measuring the inductance before the assembly is completed, that is, in the rough assembly state, and the required inductance is obtained. When this happens, fix both cores with adhesive with the spacer inserted. In other words, by moving the summer core in the longitudinal direction, the magnetic resistance of the magnetic path formed by both cores changes, and the inductance changes. Therefore, the inductance can be easily adjusted by moving the summer core in the longitudinal direction, and the inductance can be changed continuously.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the first embodiment of the present invention, FIG. 2 is a sectional view when the inductance is maximum, FIG. 3 is a sectional view when the inductance is minimum, and FIG. 5 is a cross-sectional view showing a modification of the second embodiment of the present invention; FIG. 6 is a cross-sectional view showing a modification of the second embodiment; FIG. 7 is a cross-sectional view showing a modification of the second embodiment; 8 is a sectional view showing the third embodiment of the invention, FIG. 8 is a sectional view when the inductance is maximum, FIG. 9 is a sectional view when the inductance is minimum, and FIG. 10 is a modification of the third embodiment. 1) is a sectional view showing a fourth embodiment of the present invention, FIG. 12 is a sectional view showing a modification of the fourth embodiment, and FIG. 13 is an exploded perspective view showing a conventional example. figure, . FIG. 14 is an exploded perspective view showing another conventional example. 1-E half core, 21-C type core, 2, 22, 32.42
・-■Half core, 3, 23.33.43・-Spacer, 4
．． 24- Coil, 5.25- Coil frame. Patent Applicant Matsushita Electric Works Co., Ltd. Agent Patent Attorney Toshimaru Takemoto (and 2 others) Figure 1 Figure 12 (a) (i) Figure 3 @ Figure 4 Figure 5 Figure 16 Figure 8 (a) ( b''1 Figure 9 2b Figure 12 Figure 13 Day Figure μ

Claims (1)

[Claims] (1) An E-type or C-type core made of a soft magnetic material, an I-type core arranged so as to close the open end surface of the E-type or C-type core, and a gap between the E-type or C-type core and the I-type core. A choke coil consisting of an interposed spacer and a coil wound around any of the above cores, which includes the surface of the I-shaped core facing the open end surface of the E-type or C-type core, and the open end surface. A choke coil that is formed so that the distance from the flat surface varies in the longitudinal direction of the I-shaped core.