JP2007103414A - Inductor and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inductor where a clearance between a drum core and a sleeve core is constant and an inductance value can be stabilized to an almost constant value and to provide a manufacturing method of the inductor. <P>SOLUTION: The drum core 1 has circular brim parts 11 whose whole periphery of an outer peripheral face projects much more than an outer face of the winding part on both ends of the winding part. A sleeve core 2 has a circular through hole 20 which is constituted of a high permeability ferrite material and penetrates to one direction. The through hole 20 has a plurality of projected bars 21 to 24 which are protrusively formed on an inner wall face by leaving an interval in a circumferential direction. The drum core 1 is inserted into the through hole 20 of the sleeve core 2. The outer peripheral face of the brim part 11 is brought into contact with one of the projected bars 21 to 24, and is biased and arranged. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an inductor and a manufacturing method thereof.

  An inductor provided with a drum core such as a high permeability ferrite with a winding and a sleeve core such as a high permeability ferrite covered thereon is called a magnetic shield type, and is disclosed in, for example, Patent Documents 1 and 2 .

  This type of magnetic shield type inductor has an advantage that an inductor having excellent characteristics can be formed because the sleeve core placed on the drum core can provide an effect of improving the magnetic efficiency as well as the magnetic shield function.

  However, in a magnetic shield type inductor, the inductance value varies greatly due to variations in the gap (gap) between the drum core and the sleeve core. For example, in the experimental example in which the drum core outer diameter is 1.4 mm and the sleeve core inner diameter is 1.54 mm, the inductance value is 28% at the maximum even though the diameter difference between the drum core outer diameter and the sleeve core inner diameter is 0.14 mm. The degree also changes.

  If the diameter difference between the outer diameter of the drum core and the inner diameter of the sleeve core is reduced, the gap causing the fluctuation of the inductance value is reduced, so that it is possible to suppress variations in the inductance value. However, this makes it difficult to insert the drum core into the sleeve core.

  Therefore, in reality, the point of reducing the difference between the outer diameter of the drum core and the inner diameter of the sleeve core is compromised to some extent, and the drum core is placed on the axis of the sleeve core in order to suppress fluctuations in the inductance value. Improvements in the structure have been considered with a focus on how to place it accurately. For example, Patent Document 3 is an example.

However, since a gap based on the difference between the outer diameter of the drum core and the inner diameter of the sleeve core cannot be eliminated, it is practically unavoidable that the drum core is displaced within the gap.
Japanese Utility Model Publication No. 64-35720 Japanese Utility Model Publication No. 62-55318 Japanese Patent Laid-Open No. 5-159931

  An object of the present invention is to provide an inductor capable of stabilizing the inductance value at a substantially constant value with a constant gap between the drum core and the sleeve core, and a manufacturing method thereof.

  In order to solve the above-described problems, an inductor according to the present invention includes a drum core and a sleeve core. The drum core has circular flanges at both ends of the winding part, the entire outer periphery of which protrudes from the outer surface of the winding part. The sleeve core has a circular through-hole penetrating in one direction, and the through-hole has a plurality of ridges protruding on the inner wall surface at intervals in the circumferential direction. The drum core is inserted into the through-hole of the sleeve core, and an outer peripheral surface of the flange portion is in contact with at least one of the protrusions and is arranged in a biased manner.

  As described above, in the inductor according to the present invention, the drum core has the circular flanges having the entire circumference of the outer peripheral surface protruding from the outer surface of the winding part at both ends of the winding part. Has a circular through-hole penetrating in one direction, and the drum core is inserted into the through-hole of the sleeve core, so that it becomes a magnetic shield type inductor. Therefore, the advantage of being a magnetic shield type, that is, an effect of improving the magnetic shielding effect and magnetic efficiency can be obtained.

  The points described above are the basic configuration and operational effects of the magnetic shield type inductor. A feature of the present invention is that in the above-described magnetic shield type inductor, the sleeve core has a plurality of protrusions protruding on the inner wall surface of the through hole at intervals in the circumferential direction. The outer peripheral surface of the portion is in contact with at least one of the ridges and is arranged in a biased manner.

  According to the above configuration, a part of the outer peripheral surface of the drum core is in contact with the protrusion provided on the inner wall surface of the through hole of the sleeve core, and between the outer peripheral surface of the drum core and the inner wall surface of the through hole of the sleeve core. Since a certain gap determined by the height of the ridge is generated, there is no room for gap variation based on the difference between the outer diameter of the drum core and the inner diameter of the sleeve core. For this reason, the gap between the drum core and the sleeve core can be made constant, and the inductance value can be stabilized to a substantially constant value.

  The bias of the drum core can be obtained by bringing the drum core into contact with the sleeve core by magnetic attraction of an external magnetic field and fixing the drum core and the sleeve core at that position.

  As a specific aspect, the drum core can be configured such that the outer peripheral surface of the flange portion contacts two of the ridges and is spaced from the inner wall surface of the through hole that exists between the two ridges. In this case, between the two ridges, a gap generated between the outer peripheral surface of the flange portion of the drum core and the inner wall surface of the through hole of the sleeve core is the interval and height of the two ridges. Therefore, there is no room for gap variation based on the difference between the outer diameter of the drum core and the inner diameter of the sleeve core. For this reason, the gap between the drum core and the sleeve core can be made constant, and the inductance value can be stabilized to a substantially constant value.

  The protrusion is preferably provided linearly along the hole axial direction of the through hole. According to this arrangement, it is possible to obtain manufacturing advantages such as easy die cutting when manufacturing the sleeve core.

  The number of protrusions is preferably about 3 to 12, for example. From the viewpoint of bringing the flange portion of the drum core into contact with two adjacent ridges on the outer peripheral surface, it is preferable that the number of the ridges is four, and these are arranged in four equal parts. According to the number of protrusions, the object can be sufficiently achieved, and the sleeve core can be easily manufactured.

  The inductor according to the present invention includes two terminal pieces and a winding in addition to the above-described drum core and sleeve core as a specific and general form. Each of the terminal pieces is joined to the outer end surface of each of the flanges provided in the drum core and the outer end surface of the sleeve core. Thereby, the above-described bias is maintained. The winding is wound around the winding portion of the drum core, and the terminal is electrically connected to the terminal piece. Therefore, the winding can be drawn out of the drum core and the sleeve core via the terminal piece.

  Electrodes are formed on the outer end surface of the drum core collar and the outer end surface of the sleeve core, and terminal pieces are welded to the respective electrodes and windings. The finished product is configured as a chip-type inductor in which the sleeve core is used as it is, and the electrodes formed on the outer end surface of the drum core collar and the outer end surface of the sleeve core are used as connection electrodes to the base.

  In manufacturing the inductor according to the present invention, the drum core is inserted into the through hole of the sleeve core. Next, an external magnetic field is applied to the drum core and the sleeve core, and the drum core is attracted by its magnetic attraction, thereby biasing the position of the drum core in the sleeve core. Then, the drum core is fixed to the sleeve core at the biased position. As a result, the above-described inductor according to the present invention can be easily manufactured.

  Among the manufacturing methods according to the present invention, the process of biasing the drum core can be performed using a jig in which a large number of storage holes for storing the sleeve core and the drum core are provided and a magnet is disposed between the storage holes. .

  Further, the step of fixing the drum core to the sleeve core at the biased position is specifically a process of joining each outer end surface of the flange portion of the drum core and the outer end surface of the sleeve core with a terminal piece. .

  The manufacturing method according to the present invention is basically applied to manufacture an inductor having the above-described structure, but instead of using a sleeve core provided with a ridge on the inner wall surface of the through hole, The present invention can also be applied to the case where a drum core having a plurality of protrusions protruding at intervals in the circumferential direction is used on the outer peripheral surface of the flange portion. Also in this case, at least one of the ridges can be brought into contact with the inner wall surface of the through hole of the sleeve core by magnetic attraction, and the position of the drum core in the sleeve core can be biased. be able to.

  As described above, according to the present invention, it is possible to provide an inductor capable of stabilizing the inductance value at a substantially constant value with a constant gap between the drum core and the sleeve core and a method for manufacturing the same.

  Other objects, configurations and advantages of the present invention will be described in more detail with reference to the accompanying drawings. However, it goes without saying that the technical scope of the present invention is not limited to these illustrated embodiments.

  1 is a side view showing a main part of a magnetic shield type inductor according to the present invention, and FIG. 2 is a partial sectional view taken along line 2-2 of FIG. The illustrated inductor includes a drum core 1 and a sleeve core 2. The drum core 1 is made of a high-permeability ferrite material, and has circular flanges 11 and 12 whose outer peripheral surfaces protrude from the outer surface of the winding part 10 at both ends of the winding part 10. .

  The sleeve core 2 is also made of a high magnetic permeability ferrite material and has a circular through hole 20 that penetrates in one direction. The through-hole 20 has a plurality of ridges 21 to 24 that protrude from the inner wall surface at intervals in the circumferential direction. The ridges 21 to 24 are preferably provided linearly along the hole axis direction of the through hole 20. According to this arrangement, it is possible to obtain manufacturing advantages such as easy die cutting when manufacturing the sleeve core 2.

  The number of ridges 21 to 24 is preferably about 3 to 12, for example. From the viewpoint of bringing the outer peripheral surface of the flanges 11 and 12 of the drum core 1 into contact with two adjacent ridges 21 to 24, the number of the ridges 21 to 24 is four, and it is preferable that the four are arranged equally. According to the number of protrusions, the object can be achieved sufficiently, and the sleeve core 2 can be easily manufactured.

  From the viewpoint of supporting the flanges 11 and 12 of the drum core 1 so that the predetermined gap G1 is generated, the protrusions 21 to 24 are most preferably arc-shaped as shown, but other shapes such as a square shape are used. May be.

  The drum core 1 is inserted into the through hole 20 of the sleeve core 2, and the outer peripheral surfaces of the flange portions 11 and 12 are in contact with at least one of the ridges 21 to 24 and are arranged in a biased manner. In the drawing, the drum core 1 is in contact with two adjacent ridges 21 and 24 and is arranged in a biased direction in the direction of the ridges 21 and 24. A large gap is formed on the side opposite to the ridges 21 and 24.

  The illustrated inductor includes two terminal pieces 31 and 32 and a winding 4 in addition to the drum core 1 and the sleeve core 2. Each of the terminal pieces 31, 32 is joined 71, 72 to the outer end surface of each of the flange portions 11, 12 provided in the drum core 1 and the outer end surface of the sleeve core 2. Thereby, the above-described bias is maintained.

  The winding 4 is wound around the winding portion 10 of the drum core 1, and the terminals 41 and 42 are electrically connected to the terminal pieces 31 and 32. Accordingly, the winding 4 can be pulled out of the drum core 1 and the sleeve core 2 via the terminal pieces 31 and 32.

  The finished product can be obtained as a chip inductor having a size of 3.2 mm × 2.5 mm, for example, having the sleeve core as it is and having electrodes formed on the outer end surface of the drum core collar and the outer end surface of the sleeve core.

  As described above, in the inductor according to the present invention, the drum core 1 has the circular flange portions 11 and 12 whose entire outer peripheral surface protrudes from the outer surface of the winding portion 10 at both ends of the winding portion 10. The sleeve core 2 has a circular through hole 20 penetrating in one direction, and the drum core 1 is inserted into the through hole 20 of the sleeve core 2. It becomes an inductor. Therefore, the advantage of being a magnetic shield type, that is, an effect of improving the magnetic shielding effect and magnetic efficiency can be obtained.

  A feature of the present invention is that in the above-described magnetic shield type inductor, the sleeve core 2 has a plurality of protrusions 21 to 24 protruding on the inner wall surface of the through hole 20 at intervals in the circumferential direction. The drum core 1 is in that the outer peripheral surfaces of the flange portions 11 and 12 are in contact with at least one of the protrusions 21 to 24 and are arranged in a biased manner. In the illustrated embodiment, the drum core 1 is in contact with the two adjacent ridges 21, 24, and is arranged in the direction of the ridges 21, 24.

  According to the above configuration, a part of the outer peripheral surface of the drum core 1 is in contact with the ridges 21 and 22 provided on the inner wall surface of the through hole 20 of the sleeve core 2, and the outer peripheral surface of the drum core 1 and the sleeve core 2 are penetrated. Since a certain gap G1 determined by the height of the protrusions 21 and 22 is generated between the inner wall surface of the hole 20 and the outer diameter of the flange portions 11 and 12 of the drum core 1 and the penetration of the sleeve core 2. There is no room for fluctuation in the gap G1 based on the difference in diameter from the inner diameter of the hole 20. For this reason, the gap G1 between the drum core 1 and the sleeve core 2 can be made constant, and the inductance value can be stabilized to a substantially constant value.

  In the case of the illustrated embodiment, the drum core 1 has an outer peripheral surface of the flanges 11 and 12 in contact with two of the ridges 21 and 22, and an inner wall surface of the through hole 20 existing between the two ridges 21 and 24. Spaced apart. Therefore, a gap G1 generated between the outer peripheral surfaces of the flanges 11 and 12 of the drum core 1 and the inner wall surface of the through-hole 20 of the sleeve core 2 is between the two protrusions 21 and 24. Since it becomes a constant value determined by the distance between 21 and 24 and the height, the gap G1 based on the difference in diameter between the outer diameter of the flanges 11 and 12 of the drum core 1 and the inner diameter of the through hole 20 of the sleeve core 2 There is no room for fluctuation. For this reason, the gap G1 between the drum core 1 and the sleeve core 2 can be made constant, and the inductance value can be stabilized to a substantially constant value.

  In the case of the embodiment in which the four protrusions 21 to 24 are arranged in four equal positions, the drum core 1 has four contact positions with respect to the protrusions 21 to 24. That is, as shown in FIG. 3, when the drum core 1 comes into contact with the ridges 21 and 22, as shown in FIG. 4, when the drum core 1 comes into contact with the ridges 22 and 23, as shown in FIG. In this case, 1 contacts the ridges 23 and 24. In either case, the effects described with reference to FIGS. 1 and 2 can be obtained.

  Next, a method for manufacturing the above-described inductor will be described. FIG. 6 is a diagram for explaining the inductor manufacturing method according to the present invention. First, a flat jig 8 made of a nonmagnetic material is provided with holes Q11 to Q14, Q21 to Q24, Q31 to Q34, and Q41 to Q44 for inserting sleeve cores at appropriate intervals. The sleeve core 2 is inserted therein, and the drum core 1 with the winding 4 is inserted into the sleeve core 2. Further, a hole for inserting a magnet is provided in accordance with the arrangement of the hole into which the sleeve core 2 is inserted, and the magnets MG1 to MG4 are arranged in the hole.

  In FIG. 6, the four holes Q11 to Q14, Q21 to Q24, Q31 to Q34, and Q41 to Q44 for inserting the sleeve core have a quadrangular arrangement, and magnets MG1 to MG4 are arranged in the center of the arrangement. It has become.

  With the above arrangement, the drum core 1 inserted into the sleeve core 2 is attracted by the magnets MG1 to MG4, and the drum core 1 is in contact with two of the protrusions 21 to 24 provided on the sleeve core 2. 2 to obtain a certain gap G1. Specifically, in the core sleeve 2 and the drum core 1 disposed inside the holes Q11, Q21, Q31, and Q41, the biased arrangement shown in FIGS. 1 and 2 is obtained, and the holes Q12, Q22, Q32, In the core sleeve 2 and the drum core 1 arranged inside Q42, the bias arrangement shown in FIG. 3 is obtained. In the core sleeve 2 and the drum core 1 arranged inside the holes Q13, Q23, Q33, and Q43, the biased arrangement shown in FIG. 5 is obtained, and arranged inside the holes Q14, Q24, Q34, and Q44. In the core sleeve 2 and the drum core 1, the biased arrangement shown in FIG. 4 is obtained.

  In this state, by connecting the terminal pieces 31 and 32 to the core end surface and fixing the drum core 1 and the shield core, a fixed constant gap G1 can be obtained.

  According to the method described above, it is possible to suppress variations in the gap G1 between the drum core 1 and the shield core without using a bobbin or a base.

  The manufacturing method according to the present invention is basically applied to manufacture the inductor having the above-described structure. However, the sleeve core 2 provided with the protrusions 21 to 24 on the inner wall surface of the through hole 20 is provided. Instead of using the drum core 1, the drum core 1 having a plurality of protrusions 21 to 24 protruding at intervals in the circumferential direction on the outer peripheral surfaces of the flange portions 11 and 12 can be applied. Also in this case, at least one of the protrusions 21 to 24 can be brought into contact with the inner wall surface of the through hole 20 of the sleeve core 2 by magnetic attraction, and the position of the drum core 1 in the sleeve core 2 can be biased. The same effect can be obtained.

It is a figure which shows the principal part of the magnetic shield type | mold inductor which concerns on this invention. FIG. 2 is a partial cross-sectional view taken along line 2-2 of FIG. It is a figure which shows the principal part in another Example of the magnetic shield type | mold inductor which concerns on this invention. It is a figure which shows the principal part in another Example of the magnetic shield type | mold inductor which concerns on this invention. It is a figure which shows the principal part in another Example of the magnetic shield type | mold inductor which concerns on this invention. It is a figure explaining the manufacturing method of the inductor which concerns on this invention.

Explanation of symbols

1 Drum core 11, 12 Buttocks
2 Sleeve core 21-24 Projection
G1 gap

Claims (13)

An inductor including a drum core and a sleeve core,
The drum core has, on both ends of the winding portion, a circular flange that protrudes from the outer surface of the winding portion on the entire outer periphery.
The sleeve core has a circular through-hole penetrating in one direction, and the through-hole has a plurality of ridges projecting from the inner wall surface at intervals in the circumferential direction,
The drum core is inserted into the through hole of the sleeve core, and an outer peripheral surface of the flange portion is in contact with at least one of the ridges, and is arranged in a biased manner.
Inductor. 2. The inductor according to claim 1, wherein the bias of the drum core is obtained by bringing the drum core into contact with the sleeve core by magnetic attraction of an external magnetic field, and fixing the drum core and the sleeve core at the position. Is,
Inductor.   3. The inductor according to claim 1, wherein an outer peripheral surface of the flange portion is in contact with two of the protrusions, and an inner wall surface of the through hole that exists between the two protrusions. Is an inductor that is spaced apart.   4. The inductor according to claim 1, wherein the protrusion is linearly provided along a hole axial direction of the through hole. 5.   The inductor according to any one of claims 1 to 4, wherein the number of the protrusions is four, and the inductors are equally arranged. The inductor according to any one of claims 1 to 5, further comprising two terminal pieces and a winding,
Each of the terminal pieces is joined to the outer end surface of each of the flanges provided in the drum core and the outer end surface of the sleeve core,
The winding is wound around the winding portion of the drum core, and a terminal is electrically connected to the terminal piece.
Inductor. An inductor manufacturing method comprising:
The inductor includes a drum core and a sleeve core,
The drum core has, on both ends of the winding portion, a circular flange that protrudes from the outer surface of the winding portion on the entire outer periphery.
The sleeve core has a circular through hole penetrating in one direction,
Inserting the drum core into the through hole of the sleeve core;
Next, an external magnetic field is applied to the drum core and the sleeve core, the drum core is attracted by its magnetic attraction, and the position of the drum core in the sleeve core is biased,
Fixing the drum core to the sleeve core at a biased position;
Including steps,
Inductor manufacturing method. The manufacturing method according to claim 7, comprising:
The sleeve core has a plurality of ridges protruding on the inner wall surface of the through hole at intervals in the circumferential direction,
Contacting the outer peripheral surface of the flange with at least one of the protrusions, and biasing the position of the drum core in the sleeve core;
A manufacturing method including a process. A manufacturing method according to claim 8, comprising:
The outer peripheral surface of the flange portion of the drum core is brought into contact with two of the protrusions by the magnetic attraction, and is spaced apart from the inner wall surface of the through hole existing between the two protrusions. Method.   It is a manufacturing method described in Claim 8 or 9, Comprising: The said protrusion is a manufacturing method provided linearly along the hole axial direction of the said through-hole.   11. The manufacturing method according to claim 8, wherein the number of the protrusions is four, and four are arranged equally.   The manufacturing method according to any one of claims 7 to 11, wherein the step of fixing the drum core to the sleeve core at a biased position includes each outer end surface of the flange portion of the drum core; The manufacturing method which is a process of joining the outer end surface of a sleeve core with a terminal piece. The manufacturing method according to claim 7, comprising:
The drum core has a plurality of ridges projecting on the outer peripheral surface of the flange portion at intervals in the circumferential direction,
By the magnetic attraction, at least one of the protrusions is brought into contact with the inner wall surface of the through hole of the sleeve core, and the position of the drum core in the sleeve core is biased;
A manufacturing method including a process.