JPH0655229U - Inductor and core holder used for this - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide an inductor and a core holder used for the inductor, which can obtain the required magnetic characteristics of a laminated iron core of an electromagnetic thin steel sheet. [Structure] Stacked type split iron core 1-1 having three legs
And an iron core composed of a laminated type split iron core 1-2 that is joined to the iron core 1-1 so as to form a closed magnetic path, and three cylinders capable of storing the legs of the iron core. Insulator 3-1-1
A non-magnetic coil holder having 3-1-1 'and 3-1-2, and a coil 4-mounted on the outer periphery of the tubular insulator.
1, 4-2 and the divided iron cores 1-1, 1-2, which house the bases of the divided iron cores 1-1, 1-2 facing each other,
And core holders 2 and 2'for fastening and holding.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an inductor used for a power supply circuit of an electronic device and a core holder used for the same, and in particular, an electromagnetic thin steel plate is punched into an E-shape, a U-shape, or an I-shape, and a plurality of the laminated pieces are laminated. For example, the iron core is formed by combining E-shaped comrades, E-shaped and I-shaped, U-shaped comrades, U-shaped and I-shaped to form a day-shaped or ro-shaped iron core. The present invention relates to an inductor formed by winding an outer leg portion of a day-shaped or square-shaped iron core and a core holder used for the inductor. In addition, the term "inductor" used here means an inductance element or a transformer transformer in a narrow sense in which a winding is applied to an iron core.

[0002]

[Prior art]

 Depending on the application, the required inductance value, the number of turns of the winding, the magnitude of the current flowing through the winding, the required size, etc., the inductor's structure and size, and the magnetic material forming the iron core Not only the type, but also various shapes and structures such as winding thickness and structure.

For example, in the case of an inductor used in a low frequency power supply circuit such as a commercial power supply frequency, the saturation magnetic flux density is large because the current capacity is relatively large. Therefore, an electromagnetic thin steel plate such as silicon steel is often used. In this case, generally, the electromagnetic thin steel plate is punched into an E-shape, a U-shape, or an I-shape, and then a plurality of laminated sheets are laminated to form an E-shaped, U-shaped, or I-shaped split iron core, which is separately formed into a reel or the like. Attach the wound winding (coil) to the split iron core legs and combine split iron cores such as E-shaped comrades, E-shaped and I-shaped, U-shaped comrades, or U-shaped and I-shaped. Join and fix. As described above, when the current capacity is large, a day-shaped or square-shaped iron core is formed through a predetermined magnetic gap to avoid magnetic saturation.

Next, referring to FIGS. 6 and 7, a conventional method for stacking and fixing electromagnetic thin steel sheets and a method for joining split iron cores will be described. In FIG. 6, a core holder 7-1 for accommodating the E-shaped laminated split iron core 1-1 and the I-shaped laminated split iron core 1-2 has a cross section of the laminated split iron core 1-2. It has a U-shape with an opening that has almost the same width as the thickness, and is a foldable locking piece 7-1-1 at the end of the leg, and a locking piece 7-for attaching the inductor to the printed board. It has 1-2.

After inserting and fixing the E-shaped laminated split iron core 1-1 into the core holder 7-1, the coil 8 in which the winding wire 8-2 is wound around the winding frame 8-1 is attached to the E-shaped laminated mold. Attach it to the center leg of the split iron core 1-1. Further, the I-shaped laminated type split iron core 1-2 is inserted into the core holder 7-1, and subsequently, the patch plate having an area substantially equal to the area of the side surface of the I-shaped laminated type split iron core 1-2 in the insertion direction. Insert 7-2. Then, the locking piece 7-1-1 is bent to join and fix the E-shaped laminated split iron core 1-1 and the I-shaped laminated split iron core 1-2. An inductor formed by mounting the winding on the central leg of the core holder in this way is generally called an inner iron type inductor.

In FIG. 7, a core holder 7-1 for accommodating a U-shaped laminated split iron core 1-1 ′ and an I-shaped laminated split iron core 1-2 is the same as in the case of FIG. It has a U-shape and has a locking piece 7-1-1 and a locking piece 7-1-2.

After inserting the E-shaped laminated split iron core 1-1 into the core holder 7-1 and fixing it, the coils 8 and 8'in which the winding 8-2 is wound around the winding frame 8-1 are respectively placed in the U-shape. Attaching to the outer leg of the iron core 1-1 '. Further, the I-shaped laminated type split iron core 1-2 is inserted into the core holder 7-1, and subsequently, the contact plate having an area substantially equal to the area of the insertion direction side surface of the I-shaped laminated type split iron core 1-2. Insert 7-2. Then, the locking pieces 7-1-1 are bent to join and fix the U-shaped laminated split iron core 1-1 'and the I-shaped laminated split iron core 1-2. An inductor formed by mounting two windings on the outer leg of the core holder in this way is generally called an outer iron inductor. Generally, inexpensive iron is used as the material of the core holder 7-1.

[0008]

[Problems to be solved by the device]

 When trying to obtain large normal mode and common mode inductances with one inductor, in the case of E-shaped comrades or a combination of E-shaped and I-shaped split iron cores, the windings are placed on both outer legs. A so-called outer iron type inductor that is installed and configured is required.

In the conventional outer iron type inductor, as shown in FIG. 7, since the coils 8 and 8 ′ are mounted on the core holder 7-1 mounted on the split iron core 1-1 ′, the winding mounting is performed. In this part, the magnetic characteristics are synthesized and the problem that the magnetic characteristics of the laminated iron core of the electromagnetic thin steel sheet that is originally required cannot be obtained. As a means for improvement, it is conceivable to form a similar core holder with a non-magnetic or non-conductive material such as plastic, but there are problems such as reliability in order to maintain lamination, fixation and bonding for a long time.

Further, since the coils 8, 8'are mounted on the split iron core 1-1 'and the core holder 7-1 as described above, the diameter of the through hole of the winding frame 8-1 is increased and winding is possible. There is a problem that the area becomes small and the number of windings cannot be increased. In the case of E-shaped comrades, U-shaped comrades, or combination of split iron cores such as E-shaped and I-shaped, the same problem occurs when the windings are mounted on both outer legs.

The present invention is to provide an inductor and a core holder used for the same to solve the above problems.

[0012]

[Means for Solving the Problems]

 According to the present invention, in a core holder for holding a laminated iron core that has at least two leg portions that join the base portions facing each other and joins the base portions, the core holder is Of the pair of box-shaped cases capable of accommodating the base, the two side walls of the pair of box-shaped cases facing each other among the four side walls of the one case, and the four side walls of the other case. A core holder is obtained, which has two fastening portions for fastening two side walls corresponding to the two side walls of the one case to each other.

Further, one of the two fastening portions and one of the cases are integrated with each other, and the other fastening portion and the other case are integrated with each other. Is obtained.

Further, the four side walls of the pair of box-shaped cases are made so as to be independent from each other by making a cut at the corners thereof, and among the four side walls, two side walls facing each other are formed. The cut-and-raised parts are provided with respective locking holes, and are formed by fitting fastening rods into the two locking holes of one case and the two upper and lower locking holes of the other case, respectively. The core holder is obtained.

Further, according to the present invention, the four side walls of the pair of box-shaped cases are made so as to be independent from each other by making a cut at a corner portion thereof, and the four side walls are opposed to each other. One of the two side walls is provided with a cut-and-raised part having a locking hole, the other side wall is provided with a fastening part extending to the side wall of the other case, and the locking hole of one case is provided with the other. A core holder is obtained in which a fastening portion of a case is fitted and a fastening portion of one case is fitted into a locking hole of the other case.

Further, according to the present invention, a laminated first split iron core having at least two legs and a stack joined to the first split iron core so as to form a closed magnetic circuit. An iron core consisting of a second split iron core of a mold, a non-magnetic coil holder having at least two tubular parts capable of accommodating the legs of the iron core, and a coil mounted on the outer periphery of the tubular part And a core holder for housing the bases of the first and second split iron cores facing each other and fastening and holding the first and second split iron cores, wherein the coil holder is A holder body in which a collar having two openings through which the two legs of the first split iron core can be inserted and the tubular portion provided around the opening are integrated, It is attached to the foot end of the tubular part of the holder body, and is attached to the front of the second split iron core. It is possible to obtain an inductor characterized by comprising a flange member which is mounted on a surface facing the first split iron core and has an opening portion which allows the first and second split iron cores to be joined to each other.

Further, the core holder is composed of a pair of box-shaped cases capable of accommodating the base, and the four side walls of the pair of box-shaped cases are made independent of each other by making cuts at their corners. Of the four side walls, one of the two side walls facing each other in the vertical direction has a cut-and-raised part provided with a locking hole, and the other side wall has a side wall of the other case. It is characterized in that a fastening portion extending up to is provided, a fastening portion of one case is fitted into a locking hole of one case, and a fastening portion of one case is fitted into a locking hole of the other case. To obtain an inductor.

Further, the core holder is composed of a pair of box-shaped cases capable of accommodating the base portion, and four side walls of the pair of box-shaped cases are made independent from each other by making a cut at a corner portion thereof. Of the four side walls, two side walls facing each other in the vertical direction are provided with cut-and-raised parts, each of which has a locking hole. An inductor is obtained in which fastening rods are respectively inserted into the upper and lower two locking holes of the case.

[0019]

【Example】

 The inductor of the present invention and the core holder used for the inductor will be described in detail with reference to FIGS. FIG. 1 is a view showing a process of assembling a core holder according to the present invention and an E-shaped split iron core made of a plurality of electromagnetic thin steel plates to be inserted into the core holder. In FIG. 1, the core holder 2 is substantially box-shaped, and its side walls 2-1, 2-2, 2-3, and 2-4 are independent without being joined to the adjacent side walls. Among the side surfaces facing each other in the stacking direction, the side surfaces 2-1 and 2-2 are provided with cut-and-raised portions 2-5 each having a locking hole (opening portion) 2-6 at the center thereof. Has been. Here, after inserting the E-shaped split iron core 1-1 into the core holder 2, the side walls 2-1, 2-2, 2-3, 2-4 are respectively caulked in the direction of the arrow and fixed, whereby the split Hold the iron core.

FIG. 2A is an exploded perspective view showing a process of assembling the inductor according to the present invention, and FIG. 2B is an external perspective view of the inductor according to the present invention. The figure shows an example in which a relatively thick conductor is applied. In FIG. 2 (a), the coils 4-1 and 4-2 are wound in an air-core shape instead of being wound directly on the winding frame. The coil holder is composed of the coil holder body 3-1 and the collar portion 3-1 '. The coil holder body 3-1 includes a collar 3-1-3 having three openings (not visible in the figure) through which the legs of the E-shaped split iron core 1-1 can be inserted, and the inside of the openings. A tubular insulator portion 3-1-1, 3-1-1 'integrally provided with the collar 3-1-3 around an outer opening through which the leg portions at both ends of the iron core are inserted, A cylindrical insulator part 3-1-2 is provided between the cylindrical insulator parts 3-1-1 and 3-1-1 'and is integrally molded with the collar 3-1-3. .

The collar portion 3-1 ′ has an opening portion 3-2-corresponding to an opening surface at the foot ends of the tubular insulator portions 3-1-1, 3-1-1 ′, and 3-1-2. It has 1,3-2-1 'and 3-2-2.

In addition, through holes for inserting the fastening rods 6 and 6 ′ are provided at both ends in the stacking direction of the cylindrical insulator portion 3-1-2. Also, through holes corresponding to the above through holes are provided on both sides of the opening 3-2-2 of the flange 3-1 '.

After the windings 4-1 and 4-2 are attached to the cylindrical insulator parts 3-1-1 and 3-1-1 ', respectively, the cylindrical insulator parts 3-1-1 and 3-1 are installed. -1 ', 3-1-2 Fit the opening portions 3-2-1, 3-2-1', 3-2-2 of the collar portion 3-1 'into the opening portions at the foot ends of the coil to form a coil. Form a holder.

Next, the three legs of the E-shaped split iron core 1-1 laminated and fixed to the core holder 2 are connected to the three openings of the coil holder 3-1 and the tubular insulator portion 3-1-1. 3-1-1 ', 3-1-2. On the other hand, the E-shaped division laminated and fixed to the core holder 2'inserts the three legs of the iron core 1-2 into the three openings of the flange 3-1 '. At this time, the facing surfaces of the legs of the E-shaped split iron cores 1-1 and 1-2 are joined to the three openings of the flange 3-1 '.

Further, the side walls of the core holders 2 and 2 ′ facing each other in the stacking direction are provided with cut-and-raised parts each having a locking hole. Through holes corresponding to the locking holes are provided at both ends in the stacking direction of the tubular insulator portion 3-1-2 of the coil holder body, separately from the opening portion 3-2-2 of the collar portion 3-1 '. An opening corresponding to the through hole is provided.

Two fastening rods 6, one end of which is bent into an L-shape, are passed through locking holes provided in the cut-and-raised portion of the core holder 2 ′, respectively. After that, the two fastening rods 6 pass through the opening of the flange portion 3-1 ′ and the through hole of the coil holder body 3-1 and the locking hole provided in the cut and raised portion of the core holder 2. Further, by bending the flat side at the other end into an L-shape, the two core holders 2 and 2'are fastened and fixed, and the split iron cores 1-1 and 1-2 are joined and fixed to each other. In this way, the inductor of the present invention is assembled and completed. FIG. 2B shows the assembled inductor.

The core holder 2 shown in FIG. 3A is an improvement of the core holder in FIG. In the case of FIG. 1, the shape of the core holder was box-shaped, and it had four independent side walls with cuts at the corners. On the other hand, in this case, although the core holder 4 is box-shaped, the side wall 2-1 is formed by making a cut on the outer surface of one of the side walls facing each other in the stacking direction of the split core and in the corner chamber. -1,2-1-2,2-1-2 'are formed. In addition, the side wall 2-2 (see FIG. 1) is also cut like the above.

Compared with the embodiment of FIG. 1 in which the four side walls are formed independently of each other with the corners as boundaries, it is effective in stacking and fixing particularly when the thin steel plates are thin. For example, when the four side walls are independent from each other on both sides of each side and each corner, when the side walls are bent in the sheet metal work for manufacturing the core holder, a gap is often opened at the corner. Therefore, for example, in the case of a relatively thick electromagnetic thin steel plate having a thickness of 0.5 mm, there is no problem with the gap, but for example, a very thin electromagnetic thin steel plate having a thickness of 0.1 mm. In this case, the electromagnetic thin steel plates may stick out from the gap, which may cause misalignment of the stack when the stack is fixed. By caulking the electromagnetic thin steel plates with this core holder, it is possible to fix the electromagnetic thin steel plates in a laminated manner without misalignment, and a highly reliable inductor can be obtained.

FIG. 3 (b) shows that after inserting the split cores into the two core holders shown in FIG. 3 (a), the coil holder 5 with the coil 4 attached is sandwiched between the two core holders. , Two fastening rods 6 are respectively inserted into the cut-and-raised parts 2-5, 2-5 'provided on the core holder 2, and the cut-and-raised parts 2-5, 2 provided on the core holder 2' It shows an inductor formed by fitting to -5 '.

FIG. 4 (a) is a diagram showing an assembly process of another core holder according to the present invention and an E-shaped split iron core made of a plurality of electromagnetic thin steel plates to be inserted into the core holder, FIG. 4 (b) is a view showing an assembling process of another core holder of the present invention and an I-shaped split iron core to be inserted into the core holder, and FIG. 4 (c) is a view of the present invention. It is the figure which showed the other inductor.

In FIG. 4A, the core holder 2 is substantially box-shaped, and its side walls 2-1, 2-2, 2-3, and 2-4 are independent without being joined to the adjacent side walls. ing. Of the side surfaces facing each other in the stacking direction, one side surface 2-1 is provided with a cut-and-raised portion 2-5 having a locking hole (opening portion) 2-6 at the center thereof, and the other side surface 2-1. On the side wall 2-2, a rod-shaped fastening band 2-7 is provided integrally with the core holder. Here, after inserting the E-shaped split iron core 1-1 into the core holder 2, the side walls 2-1, 2-2, 2-3, 2-4 are respectively caulked in the arrow directions and fixed.

In FIG. 4 (b), the core holder 2 ′ is substantially box-shaped, and like the case of FIG. 4 (a), side walls 2-1 ′, 2-2 ′, 2-3 ′, 2-4 ′. Are independent without being joined to the sidewalls on both sides. Of the side walls facing each other in the stacking direction, one side wall 4-1 '(not visible in the figure) has a locking hole 2-6' in the center thereof as in FIG. 4 (a). The cut-and-raised portion 2-5 ′ having the core holder 2 ′ is provided on the other side surface 2-2 ′ so as to be fastened to the cut-and-raised portion 2-5 of FIG. 4A. It is provided integrally with.

Here, after inserting the E-shaped split iron core 1-1 into the core holder 2 ′, the side walls 2-1 ′, 2-2 ′, 2-3 ′, and 2-4 ′ are respectively inserted in the arrow directions. Tighten and fix. Here, the core holders 2 and 2'on which the E-shaped split iron core 1-1 and the I-shaped split iron core 1-2 are mounted are exactly the same, and the fastening bands 2-7 and 2-7 'are locked respectively. After fitting to the portions 2-5 and 2-5 ', the fastening band and the locking portion are fastened by bending the tips of the fastening bands 2-7 and 2-7'. Therefore, by this fastening, the two split iron cores 1-1 and 1-2 are joined and fixed.

FIG. 4 (c) is a view showing an inductor according to the present invention. The inductor is divided into core holders 2 and 2'as shown in FIGS. 4 (a) and 4 (b), respectively. After inserting 1-1 and 1-2, the coil holder 5 is sandwiched between the core holders 2 and 2 ', and the fastening bands 2-7 and 2-7' are engaged, respectively, as in the assembly process shown in FIG. It is formed by fitting to the stop portions 2-5 and 2-5 '.

In FIG. 5 (a), this core holder 2 is provided on the outer surface of one of the side walls facing each other in the stacking direction of the split cores, as in the core holder shown in FIG. 3 (a). Moreover, the side walls 2-1-1, 2-1-2, 2-1-2 'are formed by making a cut in the corner vicinity. In addition, the side wall 2-2 (see FIG. 1) is also cut in the same manner as above. Similar to the core holder shown in FIG. 3A, this core holder can also be laminated and fixed on the electromagnetic thin steel plates without displacement, and a highly reliable inductor can be obtained.

FIG. 5 (b) shows that after inserting the split cores into each of the two core holders shown in FIG. 5 (a), the coil holder 5 with the coil 4 attached is sandwiched between the two core holders. , An inductor formed by fitting a fastening band provided on each core holder into a locking hole provided on each core holder. In addition, in the case of an inductor that needs to flow a large current, a non-magnetic and non-conductive magnetic gap is required to avoid magnetic saturation, but in the case of this embodiment, two split iron core legs are used. Magnetic saturation can be avoided by sandwiching the non-magnetic or non-conductive magnetic gap in the joint.

In addition, in the inductor configured by the method described above, it is made stronger by impregnating the whole of the windings 4-1 and 4-2 excluding the end portions with the insulating varnish or by molding with the molding resin. It goes without saying that an inductor with high reliability in junction and weather resistance can be obtained.

Further, in the embodiment, the combination of the split iron cores is explained as the case of the E-shaped comrades or the combination of the E-shaped and the I-shaped, but the combination of the U-shaped comrades, the combination of the U-shaped and the I-shaped divided iron cores. However, the same effect can be obtained.

[0039]

[Effect of device]

 According to the present invention, since the windings are not directly attached to the split iron core and the core holder, the magnetic characteristics of the laminated iron core of the electromagnetic thin steel sheets that are conventionally required can be obtained.

Further, since the winding is not wound around the core holder, the diameter of the air core of the winding is reduced accordingly and the number of windings can be increased.

[Brief description of drawings]

FIG. 1 is a view showing a process of assembling a core holder and an E-shaped split iron core to be inserted into the core holder according to the present invention.

FIG. 2 (a) is an exploded perspective view showing a process of assembling an inductor according to the present invention, and FIG.
FIG. 3 is a perspective view showing the appearance of an inductor according to the present invention.

FIG. 3 (a) is a perspective view showing the structure of another core holder according to the present invention, and FIG. 3 (b) is FIG.
It is an external appearance perspective view of the inductor which uses the core holder shown by (a).

4 (a) is a diagram showing an assembly process of another core holder and an E-shaped split iron core to be inserted into the core holder according to the present invention, and FIG. a)
FIG. 4C is a view showing an assembly process of a core holder paired with the core holder shown in FIG. 4 and an I-shaped split iron core to be inserted into the core holder, and FIG. 4 (b) is an external perspective view of an inductor using the core holder shown in FIG.

5 (a) is a perspective view showing the structure of another core holder of the present invention, and FIG. 5 (b) is a perspective view of the core holder shown in FIG. 5 (a). It is an external appearance perspective view of an inductor.

FIG. 6 (a) is an exploded perspective view showing a process of a conventional inductor assembling process, and FIG. 6 (b) is an external perspective view of the conventional inductor.

FIG. 7 (a) is an exploded perspective view showing a process of assembling another conventional inductor, and FIG.
FIG. 6 is an external perspective view of another conventional inductor.

[Explanation of symbols]

1-1, 1-2 Laminated split iron core 2, 2 ', 7-1 Core holder 2-1, 2-2, 2-3, 2-4, 2-1', 2-2
', 2-3', 2-4 ', 2-1-1, 2-1-2, 2
-1-2 'Side wall 2-5, 2-5' Cut-and-raised part 2-6, 2-6 'Locking hole 2-7, 2-7' Fastening part 3-1 Coil holder main body 3-1 'Collar part 3-1-1, 3-1-1 ', 3-1-2 Cylindrical insulator 3-2-1, 3-2-1', 3-2-2 Opening part 4-1, 4-2 8,8 'coil 5 coil holder 6 fastening rod 8-1 winding frame 8-2 winding

Claims (7)

[Scope of utility model registration request] 1. A core holder for holding a laminated iron core that has at least two legs that join bases facing each other and that joins the bases, and the core holder is the A pair of box-shaped cases capable of accommodating the base, two side walls of the pair of box-shaped cases that face each other among the four side walls of the one case, and one of the four side walls of the other case. Core holder having two fastening portions for fastening the two side walls corresponding to the two side walls of the case to each other. 2. The core holder according to claim 1, wherein
A core holder, wherein one of the two fastening portions is integrated with the one case, and the other fastening portion is integrated with the other case. 3. The core holder according to claim 1, wherein
The four side walls of the pair of box-shaped cases are made so as to be independent from each other by making a cut at the corners, and two side walls of the four side walls facing each other are provided with locking holes. A core holder characterized in that a cut-and-raised portion is provided, and fastening rods are respectively fitted into two locking holes of one case and two upper and lower locking holes of the other case. 4. The core holder according to claim 2, wherein
The four side walls of the pair of box-shaped cases are made so as to be independent from each other by making a cut in the corner portion thereof, and one of the two side walls facing each other of the four side walls has a locking hole. A cut-and-raised part is provided, and a fastening part extending to the side wall of the other case is provided on the other side wall, and the fastening part of the other case is fitted into the locking hole of the one case, A core holder characterized by being formed by fitting a fastening portion into a locking hole of the other case. 5. A laminated first split iron core having at least two legs and a laminated second split iron core joined to the first split iron core so as to form a closed magnetic circuit. An iron core consisting of an iron core and at least 2 capable of accommodating the legs of the iron core
A non-magnetic coil holder having two tubular portions, a coil mounted on the outer periphery of the tubular portion, and bases of the first and second split iron cores facing each other are housed in the first and second And a core holder for fastening and holding the split iron cores, wherein the coil holder has a flange having two openings through which the two legs of the first split iron core can be inserted, and the opening. A holder main body that is integrated with the tubular portion provided around the portion, and is attached to the foot end of the tubular portion of the holder main body, and the first split iron core of the second split iron core An inductor mounted on the surface opposite to the flange member, the flange member having an opening for allowing the first and second split iron cores to join together. 6. The inductor according to claim 5, wherein the core holder comprises a pair of box-shaped cases capable of accommodating the base, and four side walls of the pair of box-shaped cases have cuts at their corners. The four side walls are formed so as to be independent from each other, and one of the two side walls facing each other in the vertical direction is provided with a cut-and-raised part having a locking hole, and the other side wall is provided. A fastening part extending to the side wall of the other case is provided, the fastening part of the other case is fitted into the locking hole of one case, and the fastening part of one case is fitted into the locking hole of the other case. An inductor characterized in that 7. The inductor according to claim 5, wherein the core holder comprises a pair of box-shaped cases capable of accommodating the base, and four side walls of the pair of box-shaped cases have cuts at their corners. It is designed to be inserted and independent of each other. Of the four side walls, two side walls facing each other in the vertical direction are provided with cut-and-raised parts each having a locking hole. An inductor formed by fitting a fastening rod into each of the locking hole and the upper and lower two locking holes of the other case.