JPH0795488B2 - E type core - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an E-shaped core made of a magnetic material used for a magnetic core such as a transformer, a choke coil, and a noise filter. The present invention relates to an E-shaped core whose structure is effectively utilized.

(Prior Art) In recent years, there has been an increasing demand for miniaturization of electronic devices, and in particular, there has been a demand for thin and lightweight electronic devices that can be carried and used outdoors or indoors.

Therefore, there is a strong demand for downsizing and weight reduction of transformers, choke coils, noise filters and the like used in these electronic devices.

Therefore, even for a core made of a magnetic material used as a magnetic core of the transformer, choke coil, noise filter, etc., there is a strong demand for thinning and weight reduction, and various proposals have been made so far. .

An E-type core is generally used as a magnetic core incorporated in the transformer or the like, and a conventional example of the E-type core will be described with reference to FIG.

An E-shaped core 1 made of a magnetic material such as ferrite has a pair of first side magnetic legs 3 each having a first groove 6 and a second groove 7 on both left and right sides of a central magnetic leg 2 having a substantially square cross section. And the second
The side magnetic legs 4 are arranged so as to face each other so as to be sandwiched therebetween, and one end of each of the central magnetic leg 2, the first side magnetic leg 3 and the second side magnetic leg 4 is connected by a yoke portion 5. .

At this time, the other end surfaces of the central magnetic leg 2, the first magnetic leg 3 and the second magnetic leg 4 are formed on the same plane, and
In order to optimize the magnetic characteristics of the die core 1, the central magnetic leg 2
Is formed to be equal to the sum of the cross-sectional areas of the first magnetic leg 3 and the second magnetic leg 4.

When the E-shaped core 1 is assembled in a transformer or the like, a coil bobbin 8 made of a coil around which an enamel wire or the like is wound is fitted to the central magnetic leg 2 as shown by a phantom line in FIG. Further, it is fixed in combination with an E-type or I-type core by a fixing fitting or the like not shown.

When the coil bobbin 8 is fitted to the E-shaped core 1, the upper and lower windings of the coil bobbin 8 are projected in the Z width from the upper and lower surfaces of the central magnetic leg 2 of the E-shaped core 1, and thus the E-shaped core 1 It cannot be said that the dimensions of each part are effectively utilized in the construction design of.

Moreover, when the transformer or the like is mounted on an electronic circuit board or the like, the protruding winding portion of the Z width serves as a mounting portion on the board or the like, which causes a problem such as poor stability.

Therefore, while satisfying the condition that the cross-sectional area of the central magnetic leg is equal to the sum of the cross-sectional areas of the first-side magnetic leg and the second-side magnetic leg, the E-shaped core has been designed to effectively utilize the dimensions of each part Has been devised, and this E-type core will be described with reference to FIG.

The E-shaped core 11 has a laterally elongated central magnetic leg 12 extending from a substantially lower front center of a yoke portion 15 and a first groove 16 so as to sandwich the left and right sides of the central magnetic leg 12. And second groove 17
The first side magnetic leg 13 and the second side magnetic leg 14 are arranged opposite to each other, and one ends of the first side magnetic leg 13 and the second side magnetic leg 14 are connected by the yoke portion 15.

Further, the E-shaped core 11 includes the central magnetic leg 12 and the first side magnetic leg 13
And the other end surface of the second magnetic leg 14 is formed on the same surface, and the lower surfaces of the central magnetic leg 12, the first magnetic leg 13 and the second magnetic leg 14 are formed on the same surface. It is composed by.

A coil bobbin 18 is fitted to the central magnetic leg 12 of the E-shaped core 11 as shown by an imaginary line in the figure, and further combined with an E-shaped or I-shaped core to form a transformer or the like. It has become so.

According to the E-shaped core 11, since the central magnetic leg 12 is elongated in the lateral direction, the height of the central magnetic leg 12 is increased by the first magnetic leg 13, the second magnetic leg 14, and The height of the yoke portion 15 is lower than that of the yoke portion 15, so that there is a space above the central magnetic leg 12 and the coil bobbin fitted to the central magnetic leg 12 is provided.
The upper winding portion of 18 does not project above the upper surfaces of the first side magnetic leg 13, the second side magnetic leg 14, and the yoke portion 15, and therefore, the structural design corresponding to the downsizing of the E-shaped core 11 is achieved. Has been done.

The E-shaped core 11 is molded by press-molding a magnetic material with a backward-moving press machine (not shown) having a plurality of pressing surfaces, for example.

According to the above-mentioned double-acting type press machine, since each pressurizing surface interlocks in multiple ways to press the magnetic material, it is difficult to mold the magnetic material so as to have a uniform density. There is a possibility that internal cracks may cause micro cracks or the like in the E-shaped core 11 when the back pressure is applied.

Further, the backward-moving press machine is large in size, complicated in operation control, and slow in molding speed, and thus unsuitable for mass production.

Therefore, a method of manufacturing an E-shaped core as shown in FIGS. 11 (a) to 11 (d) has been proposed.

According to this method, a magnetic material is molded into a molding member 28 by a single-acting press device (not shown) (FIG. 10A), and the molding member 28 is cut into cutting grooves 27a and 27b by a lathe or the like. ((B) in the figure).

Next, the molding member 28 is sequentially cut into a predetermined width (FIG. 7C), and the substantially central upper portion of the cut piece is cut to form the first magnetic leg on both left and right sides of the central magnetic leg 22. 23 and second
The side magnetic legs 24 are formed to face each other, and the central magnetic legs 2
2. E-shaped core having an E-shaped planar shape in which a yoke portion 25 that connects one end of each of the first side magnetic leg 23 and the second side magnetic leg 24 is formed
21 are manufactured.

The E-shaped core 21 has an upper surface (referred to as a central magnetic leg cutting portion 26a) formed by cutting the upper portion of the central magnetic leg 22 by the cutting processing and a width W4 'of the upper portion of the yoke portion 25 by the cutting processing.
The upper surface (referred to as the cutting portion 26b of the yoke portion) formed by cutting over the entire surface is flush with the upper surface of the first and second magnetic legs 23 and 24 (referred to as the cutting groove portion 26). And the width W4 ′ of the yoke cutting portion 26b of the cutting groove portion 26 is formed.
Is formed wider than the width W1 'of the central magnetic leg cutting portion 26a, and the width W1 of the central magnetic leg 22 is formed on both sides of the yoke portion cutting portion 26b.
It was common to form a cutting upper surface (referred to as a notch 30) protruding from 1 '.

In the E-shaped core 21, a coil bobbin (not shown) has a central magnetic leg 22.
It is fitted to the core and is combined with another E-type or I-type core to form a transformer or the like.

At this time, since the cutting groove portion 26 is formed,
As shown in FIG. 12, the height H1 ′ of the central magnetic leg 22 is greater than the height H2 ′ of the first side magnetic leg 23 and the second side magnetic leg 24.
Since H1 ′ <H2 ′, the upper winding portion of the coil bobbin is prevented from protruding from the upper surfaces of the first side magnetic leg 23 and the second side magnetic leg 24, and is stable to an electronic circuit board or the like. It contributed to mounting and miniaturization.

According to the method for manufacturing the E-shaped core, it is not necessary to use the double-acting press machine, and the E-shaped core 21 can be manufactured by a general apparatus and process.

Further, in Japanese Utility Model Laid-Open No. 2-8117, as shown in the sectional view of FIG. 13, a pair of first side magnetic legs 33 and a second magnetic leg 33 and a second magnetic leg 33 having cutting grooves 37a and 37b on both sides of the central magnetic leg 32 are provided. The side magnetic legs 34 are arranged to face each other, and the central magnetic legs 32, the first side magnetic legs 33 and the second magnetic legs 33
Disclosed is an E-shaped core 31 having a shape different from that of the E-shaped core 21 configured by connecting one end of each of the side magnetic legs 34 with a yoke portion 35.

In the E-shaped core 31, the upper surface of the central magnetic leg 32 has a height H
While being cut to 1 ', the yoke 35 is
A cutting surface (referred to as a cutting groove portion 36) having a tapered portion 40 on the left and right sides and formed by cutting is formed at a height H3 'which is taller than 1'.

In the cutting groove portion 36 of the E-shaped core 31, the upper surface of the cut central magnetic leg 32 and the upper surface of the yoke portion 35 were not formed on the same plane.

(Problems to be Solved by the Invention) However, according to the conventional E-shaped cores 1, 11, 21, and 31 described above, when the coil bobbin is fitted to the central magnetic leg to assemble a transformer or the like, in the assembling process, There is a problem that the connecting portion may be damaged due to the concentration of internal stress in the connecting portion between the central magnetic leg and the yoke portion.

Further, the coil bobbin generally has a line-symmetrical shape, and in the assembly process of fitting the coil bobbin to the central magnetic leg of the E-shaped core to assemble a transformer or the like, the coil bobbin is sufficiently tentatively attached to the E-shaped core. Even after the fitting, the central magnetic legs are not fixed and internal stress concentrates and breaks, and rattling of the side magnetic legs causes a problem in assembly.

The present invention has been made in view of the above circumstances, and the coil bobbin can be reliably assembled by being locked to the E-shaped core without fear of damaging the connecting portion such as the central magnetic leg during the assembly process of the transformer and the like. It provides an E-shaped core.

(Means for Solving the Problem) The present invention is directed to a central magnetic leg, a pair of first and second magnetic legs opposed to each other so as to sandwich the central magnetic leg from the left and right, and one end of the central magnetic leg. And a yoke portion connecting one end of each of the pair of first and second magnetic legs to each other, the width of the yoke portion of the E-shaped core is made wider than the width of the first and second magnetic legs. At the same time, a central magnetic leg on at least one of the E-shaped surfaces and a part of the yoke portion are provided along the grooves provided between the central magnetic leg and the first and second magnetic legs to form the first magnetic pole and the first magnetic pole. In an E-shaped core cut so as to be lower than the height of the second side magnetic leg, the side surface of each of the first and second side magnetic legs on the side of the central magnetic leg is cut along the magnetic leg length direction. It is characterized by having a first side magnetic leg cutout portion and a second side magnetic leg cutout portion formed by simultaneous cutting to the same height as the central magnetic leg. By providing an E-type core, it is intended to achieve the above object.

(Operation) In the present invention, the first and second magnetic legs of the E-shaped core are simultaneously cut to the same height as the central magnetic leg that has been machined along the magnetic leg length direction on each side of the central magnetic leg side. Formed by
Since the side magnetic leg notch and the second side magnetic leg notch are provided, the engaging portion provided on the fitting frame (also referred to as the collar) of the coil bobbin fitted to the central magnetic leg is engaged with the notch. By stopping, the coil bobbin can be temporarily fixed in the assembly process of the transformer and the like.

Therefore, the internal stress when fitting the coil bobbin to the central magnetic leg of the E-shaped core is dispersed to the first and second side magnetic leg notches, and the internal stress is applied to the connecting portion between the central magnetic leg and the yoke portion. You can ease your focus.

Further, since the E-shaped core and the coil bobbin are temporarily fixed without rattling due to the engagement between the first and second magnetic leg notch portions and the engagement portion provided on the fitting frame of the coil bobbin,
It will not hinder the subsequent assembly process.

(Example) The Example of this invention is described in detail based on drawing.

FIG. 1 is a perspective view showing an embodiment of an E-shaped core according to the present invention, and FIG. 2 (a) is a plan view showing the E-shaped core of the same embodiment.
2 (b) is a sectional view showing an XX cross section of the E-shaped core of the same embodiment, and FIGS. 3 (a) and 3 (b) show a coil bobbin fitted to the E-shaped core of the same embodiment. FIG. 4 is a perspective view showing a transformer constituted by the E-shaped core of the embodiment,
5 (a) and 5 (b) are explanatory views for explaining another embodiment of the E-shaped core according to the present invention, and FIGS. 6 (a) and 6 (b) are other illustrations of the E-shaped core according to the present invention. 7 and 8 are perspective views showing a part of a coil bobbin fitted to an E-shaped core according to the present invention.

The E-shaped core 51 shown in FIG. 1 is manufactured by the following steps and the like.

Using a single-acting press machine for magnetic material, a pair of side pillars,
A day-molding member having a pair of common pillars connecting both ends of the side pillars and a central common pillar connecting the center portions of the pair of side pillars is molded.

The surfaces of the pair of side pillars and the central common pillar are cut along the central common pillar of the day-shaped molding member by a disc grinder or the like formed of an abrasive or the like.

At this time, the cutting process is performed so that both end surfaces of the disc grinder are hooked on the side pillars (that is, the cutting width is wider than the interval between the side pillars), and the disc grinder is axially attached. The cutting depth depends on the installation height of the rotating shaft.

In addition, since the press surface of the single-acting type press machine is processed into a flat surface, the upper surface and the lower surface of the pair of side columns, the pair of common columns, and the center common column of the date forming member have the same surface. is doing.

Next, a pair of E-shaped cores are manufactured by cutting the pair of common pillars and the center common pillar of the day molding member at approximately the center.

As shown in FIG. 1, the E-shaped core 51 manufactured by the above method has the first groove 56 and the second groove 57 on both sides of the central magnetic leg 52.
And a pair of first side magnetic leg 53 and second side magnetic leg 54 are arranged so as to face each other so as to be sandwiched from the left and right, and the central magnetic leg 52, the first side magnetic leg 53 and the second side magnetic leg 54 One end of each is connected by a yoke portion 55, and by the cutting process, a space is provided above the central magnetic leg 52 of the E-shaped core 51 and the yoke portion 55. The upper surface of the central magnetic leg 52 (referred to as the central magnetic leg cutting portion 61a) and the upper surface of the yoke portion 55 (yoke portion cutting portion 6) which is lower in height than the second side magnetic legs 53, 54.
1b) is formed.

In the E-shaped core 51, the central magnetic leg cutting portion 61a and the yoke portion cutting portion 61b are on the same plane, the cutting groove portion 61 is formed together, and the cutting width is the first and second side magnets. Since the disk type grinder that is wider than the space between the legs is used, the cutting is performed on each side face of the first magnetic leg 53 and the second magnetic leg 54 on the central magnetic leg side in the magnetic leg length direction. A cutting surface having a width W5 formed by simultaneous cutting up to the same height as the machined central magnetic leg cutting portion 61a (referred to as first side magnetic leg notch 63 and second side magnetic leg notch 64) is formed. Has been formed.

At this time, there is a relationship of W1 <W4 between the width W1 of the central magnetic leg cutting portion 61a and the width W4 of the yoke portion cutting portion 61b.
The upper surface portion formed by cutting left and right by subtracting W1 from is the portion corresponding to the excess cutout portion 60 described in the conventional example.

In the E-shaped core 51, as can be seen by referring to FIG. 2A, the width W2 of the first magnetic leg 53 or the second magnetic leg 54,
The yoke portion 55 is wider than the first side magnetic leg 53 and the second side magnetic leg 54 so that the relationship with the width W3 of the yoke portion 55 is W2 <W3.

That is, from the relationship of W2 <W3, the cross-sectional area of the excess cutout portion 60 in the yoke portion 55 is determined by the first magnetic leg 53 and the second magnetic leg.
While following the range that is not smaller than the cross-sectional area of 54, the cross-sectional area of the central magnetic leg 52 is such that the first magnetic leg 53 and the second magnetic leg 54
It is the sum of the cross-sectional areas of.

When cutting the central magnetic leg 52 and the yoke portion 55, the first side magnetic leg 53 and the second side magnetic leg 54 have a first side magnetic leg notch 63 and a second side magnetic leg having a W5 width. The leg notches 64 are formed respectively, but because of the relationship of W2 <W3, the cross-sectional area of the extra notches 60 is not smaller than that of the first magnetic leg 53 and the second magnetic leg 54. In the cutting step, the cutting groove 61
The cutting width and cutting depth of are determined.

Further, as shown in FIG. 3 (a), a coil bobbin 101 including a coil wound with an enameled wire or the like is formed with an insertion hole 94 through which the central magnetic leg 52 of the E-shaped core 51 is inserted. Fitting frames 95 are attached to both ends of the winding frame 93 in the longitudinal direction, and the fitting frames 95 are supported by a pedestal 96.

At this time, the E-shaped core 51 is provided on both upper and left sides of the fitting frame 95.
Of the first magnetic leg 53 and the second magnetic leg 54 of the
Locking protrusions 103a and 103b are formed so that the side magnetic leg notch 63 and the second side magnetic leg notch 64 are contacted and temporarily fixed.

Further, the pedestal 96 is provided with an input / output pin 92 for transmitting / receiving an electric signal to / from the outside, which is planted in a lower portion.

Therefore, the center magnetic leg of the pair of E-shaped cores 51 is
52, the first magnetic leg 53 and the second magnetic leg 54 are fitted to the coil bobbin 101, whereby the central magnetic leg 52 is inserted into the insertion hole 9
4, the first side magnetic leg cutout 63 of the first side magnetic leg 53 and the second side magnetic leg cutout 64 of the second side magnetic leg 54 are locked by the locking projections 103a,
It is fixed and locked by 103b.

The state in which the coil bobbin 101 is incorporated in the E-shaped core 51 as described above can be understood by referring to FIG. 2 (b), and the height H1 of the central magnetic leg 52 can be understood.
However, since the cutting groove portion 61 is formed by cutting,
The height is set to be lower than the height H2 of the first magnetic leg 53 and the second magnetic leg 54.

That is, the coil bobbin 101 (indicated by phantom lines), which is composed of a coil around which an enamel wire or the like is wound, is
It is prevented that one upper winding portion of the coil bobbin, when fitted to the above, protrudes from the height H2 of the first side magnetic leg 53 and the second side magnetic leg 54.

Further, in the E-shaped core 51, due to the relationship of W1 <W4, the extra cutouts 60 are formed on the left and right of the yoke cutting portion 61b, but W2 <W3
Therefore, it is possible to prevent the cross-sectional area of the extra cutout 60 from becoming smaller than the cross-sectional area of the first side magnetic leg 53 or the second side magnetic leg 54. , The extra notch
Magnetic saturation below a predetermined value at 60 is avoided.

Further, the first side magnetic leg 53 and the second side magnetic leg 54 of the E-shaped core 51.
First side magnetic leg notch 63 and second side magnetic leg notch 64, respectively.
To form the locking protrusions 103a, 103 of the coil bobbin 101.
Since the coil bobbin 101 is configured to be locked by b, when the central magnetic leg 52, the first magnetic leg 53 and the second magnetic leg 54 of the E-shaped core 51 are fitted to the coil bobbin 101. It is possible to disperse and relax the internal stress generated in the.

Further, the first side magnetic leg notch 63 and the second side magnetic leg notch
The coil bobbin 101 can be temporarily fixed to the E-shaped core 51 by abutting and locking the 64 and the locking projections 103a and 103b, respectively, so that the fitted E-shaped core 51 does not rattle, and It can assist the assembly process of transformers and the like.

As shown in FIG. 3B, a coil bobbin 105 having a frame lead 98 extending from the side surface of the pedestal 96 may be used instead of the input / output pin 92.

Next, an example in which a transformer is configured by using one set of the E-type core 51 described above will be described with reference to FIG.

The E-shaped core 51 and another E-shaped core forming a pair with the E-shaped core 51 are combined, and a central magnetic leg 52 of the E-shaped core 51 is combined.
In the insertion hole 94 of the coil bobbin 101, and the first magnetic leg 5
The transformer 100 is configured by fitting and locking the third magnetic leg 54 and the second magnetic leg 54 on the locking protrusions 103a and 103b, respectively, and fixing them by fixing fittings or the like not shown.

Next, another embodiment of the present invention will be described with reference to FIGS. 5 (a) and 5 (b).

The same parts as those in the previous embodiment are designated by the same reference numerals and the description thereof will be omitted.

In the figure, on each side surface of the first magnetic leg 53 of the E-shaped core 71 and the central magnetic leg of the second magnetic leg 54, simultaneous cutting is performed to the same height as the central magnetic leg in the magnetic leg length direction. First magnetic leg notch formed
73 and the second magnetic leg notch 74 are formed, but at the time of this cutting, the ridge is cut by a disc grinder or the like having a curved shape, and has a curved shape that is not a plane. First side magnetic leg cutouts 73 and second side magnetic leg cutouts 74 are formed.

Further, at the time of this cutting process, the cross-sectional area of the central magnetic leg 52 is
It follows the convention that the cross-sectional areas of the first magnetic leg 53 and the second magnetic leg 54 are summed.

Further, chamfered portions 76 and 77 are formed on outer lower portions of the first side magnetic leg 53 and the second side magnetic leg 54.

As shown in FIG. 7, the E-shaped core 71 configured as described above has a curved portion matching the curved portions of the first side magnetic leg cutout portion 73 and the second cutout portion 74, as shown in FIG. A coil bobbin 111 having stop projections 113a and 113b is used.

According to the E-shaped core 71, the engaging protrusions 113a and 113b of the coil bobbin 111 engage with the first side magnetic leg cutout portion 73 and the second side magnetic leg cutout portion 74 and are temporarily fixed. It has the same excellent effect as the example.

Another embodiment of the present invention will be described with reference to FIGS. 6 (a) and 6 (b).

The same parts as those in the previous embodiment are designated by the same reference numerals and the description thereof will be omitted.

Central magnetic leg of first side magnetic leg 53 and second side magnetic leg 54 of E-shaped core 81
The first side magnetic leg notch 83 and the second side magnetic leg notch 84 which are tapered from the upper surface to the cutting groove 61 are provided on the opposing side faces on the 52 side.
Are formed.

As shown in FIG. 8, the E-shaped core 81 is provided with locking projections 123a and 123b which are tapered in accordance with the tapered first magnetic leg notch 83 and second magnetic leg notch 84, respectively. The coil bobbin 121 having is used.

Also in the E-shaped core 81 configured as described above, the E-shaped core
It is needless to say that the 81 and the coil bobbin 121 are locked and temporarily fixed, and the same excellent effects as those of the previous embodiment are achieved.

In addition, as a reminder, the first magnetic leg notch and the second magnetic leg notch are cut to the same height as the central magnetic leg and the cutting groove of the yoke as will be apparent from the above embodiment. Therefore, it can be formed simultaneously with the cutting groove portion.

Therefore, it is not necessary to add another extra cutting process.

When iron powder is applied to the magnetic material, a dust core is formed by pressure molding, and when ferrite powder is applied, a binder is added to the ferrite powder to granulate and add. A ferrite core is formed by pressure molding and further firing.

(Effects of the Invention) Since the E-type core according to the present invention is configured as described above, it has the effects described below.

(1) A first side magnetic leg cutout portion and a second side magnetic leg cutout portion are formed in the first side magnetic leg and the second side magnetic leg of the E-shaped core, respectively, and the coil bobbin is engaged by the locking protrusion of the coil bobbin. The transformer is configured to stop so as to disperse and relax the internal stress generated when the central magnetic leg, the first magnetic leg and the second magnetic leg of the E-shaped core are fitted to the coil bobbin. It has an excellent effect that damage of the E-shaped core can be prevented when assembling the above.

(2) Further, the first side magnetic leg cutout portion and the second side magnetic leg cutout portion are respectively brought into abutment with the locking projections provided on the fitting portion of the coil bobbin, whereby the coil bobbin is E-shaped. Since it can be temporarily fixed to the core 51, it has an excellent effect that the assembly process of the transformer and the like after fitting can be assisted, and reliable assembly can be performed.

[Brief description of drawings]

1 is a perspective view showing an embodiment of the E-shaped core according to the present invention, FIG. 2 (a) is a plan view showing the E-shaped core of the same embodiment, and FIG. 2 (b) is an E of the same embodiment. 2B is a sectional view showing an X-X section of the E-shaped core of the same embodiment, and FIGS. 3A and 3B are the same embodiment. FIG. 4 is a perspective view showing a coil bobbin fitted to the E-shaped core of FIG. 4, FIG. 4 is a perspective view showing a transformer constituted by the E-shaped core of the same embodiment, and FIGS. FIG. 6 (a) and FIG. 6 (b) are explanatory views for explaining another embodiment of the E-shaped core according to the present invention, FIGS. 6 (a) and 6 (b) are illustrations for explaining another embodiment of the E-shaped core according to the present invention. FIG. 11 is a perspective view showing a part of a coil bobbin fitted to an E-shaped core according to the present invention, FIGS. 9 and 10 are perspective views showing a conventional E-shaped core, and FIGS. ) Is conventional Explanatory drawing explaining the manufacturing process of E type core, FIG. 12 is sectional drawing which shows the notched cross section of the same prior art example, and FIG. 13 is sectional drawing which shows the notched cross section of other prior art example. Is. 51 …… E-shaped core, 52 …… Central magnetic leg, 53 …… First side magnetic leg, 54 …… Second side magnetic leg, 55 …… Yoke part, 56 …… First groove, 57 …… Second Groove, 60 …… Excessive cutout part, 61 …… Cutting groove part, 61a …… Central magnetic leg cutting part, 61b …… Yoke part cutting part 63 …… First side magnetic leg notch part, 64 …… Second side magnetic leg Notch.

Claims (1)

[Claims] 1. A central magnetic leg, a pair of first and second side magnetic legs arranged to face each other so as to sandwich the central magnetic leg from the left and right, one end of the central magnetic leg and the pair of first and second magnetic legs. A width of the yoke portion of an E-shaped core having a yoke portion that connects one ends of the two-side magnetic legs to each other is made wider than the width of the first and second side magnetic legs, and at least one E-shaped surface The central magnetic leg and a part of the yoke portion along the grooves formed between the central magnetic leg and the first and second magnetic legs, and the height of the first and second magnetic legs is greater than the height of the first and second magnetic legs. In the E-shaped core that is cut so as to be low, at the same height as the cut central magnetic leg over the magnetic leg length direction on each side of the first and second side magnetic legs on the central magnetic leg side at the same time. An E-shaped core having a first side magnetic leg cutout portion and a second side magnetic leg cutout portion formed by cutting.