JP2021044338A - Coil device - Google Patents

Abstract

To provide a coil device having a gap hole having a shape suitable for improving the durability of a gap hole mold.SOLUTION: A coil device includes a coil and a core that forms a magnetic path of a magnetic flux generated by the coil, and a gap is formed on the magnetic path. The core is a laminated core in which a plurality of core plates are laminated. The gap is an elongated hole formed in the core, has a gap length of 1.6 times or more the plate thickness of the core plate in a first portion of the elongated hole, and has a gap length of 1.6 times or less the thickness of the core plate, and has a hole shape in which the elongated hole does not have an acute-angled portion in a second portion of the elongated hole other than the first portion.SELECTED DRAWING: Figure 3

Description

The present invention relates to a coil device.

A coil device including a coil and a core that forms a magnetic path of the magnetic flux generated by the coil is known. For example, Patent Document 1 describes a specific configuration of this type of coil device.

In the coil device described in Patent Document 1, a long hole is formed in the core in a direction orthogonal to the magnetic path. This elongated hole is formed by punching a core material with a die, and functions as a gap on a magnetic path. Due to this gap, magnetic saturation is less likely to occur in the coil device, and the inductance value can be secured even in the high current band.

Jitsukaisho 50-152149 Gazette

It is necessary to narrow the gap length depending on the inductance, DC superimposition characteristics, and magnetic permeability required for the coil device. In order to narrow the gap length in Patent Document 1, it is necessary to make a thin gap hole die for punching a long hole (referred to as “gap hole” for convenience) from the core material. However, if the mold is made thin, it is difficult to ensure the durability of the mold, and the mold is easily damaged.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a coil device having a gap hole having a shape suitable for improving the durability of a gap hole mold. Is.

The coil device according to the embodiment of the present invention includes a coil and a core that forms a magnetic path of the magnetic flux generated by the coil, and a gap is formed on the magnetic path. The core is a laminated core in which a plurality of core plates are laminated. The gap is an elongated hole formed in the core, has a gap length of 1.6 times or more the plate thickness of the core plate in the first portion of the elongated hole, and is the first portion of the elongated hole other than the first portion. The second portion has a gap length of 1.6 times or less the plate thickness of the core plate, and has a hole shape in which the elongated hole does not have an acute-angled portion.

By forming the gap in this way, the mold becomes thin (that is, the plate shape is 1.6 times or less the thickness of the core plate), and there is a concern that the durability may be reduced. It can be made into a shape that does not have a portion. That is, the gap shape according to the embodiment of the present invention is suitable for improving the durability of the mold because the acute-angled portion that is particularly liable to be damaged can be eliminated from the mold due to the thin plate shape. ..

The elongated hole may have a shape having a gap length of less than 1.6 times the plate thickness of the core plate in the second portion.

By forming the gap in this way, the portion (that is, the portion corresponding to the gap length less than 1.6 times the plate thickness of the core plate) that is concerned about the decrease in durability becomes thicker (that is, the portion corresponding to the gap length) That is, a portion corresponding to a gap length of 1.6 times or more the plate thickness of the core plate) is formed in the mold, which is suitable for improving the durability of the mold.

The first portion includes, for example, both ends of an elongated hole.

By forming the gap in this way, the end portion of the mold (that is, the portion corresponding to both ends of the elongated hole) can be formed to be thicker than the other portion of the mold. Suitable for improving durability.

The coil device may have a configuration in which a part of the core is inserted into the air core portion of the coil. In this case, the gap is arranged in the air core portion.

By arranging the gap inside the air core portion of the coil, the leakage flux from the gap is reduced as compared with the case where the gap is arranged outside the air core portion of the coil.

The hole shape of the gap is a pair of straight holes having a width less than 1.6 times the plate thickness of the core plate and a pair formed at both ends of the straight holes and having a diameter of 1.6 times or more the plate thickness of the core plate. It may have a round hole of.

The coil device may have a gap filled with a magnetic resin obtained by adding a resin to a soft magnetic powder.

By filling the gap with a magnetic resin, the effective magnetic permeability can be adjusted, and the DC superimposition characteristic can be adjusted so that magnetic saturation is less likely to occur. Further, by filling the gap with a magnetic resin, the rigidity of the core around the gap is improved. Therefore, the vibration of the core due to the electromagnetic attraction generated in the gap and the noise caused by this vibration can be suppressed to a small extent. Further, by filling the gap with the magnetic resin, the leakage flux from the gap is reduced, and the occurrence of eddy current loss in the coil is reduced. Further, by filling the gap with the magnetic resin, the magnetic flux also flows through the gap (in other words, the magnetic resin), so that the concentration of the magnetic flux flowing on both sides of the gap is relaxed and the heat generation of the core is suppressed.

For the magnetic resin, for example, the amount of the resin added to the soft magnetic powder is in the range of 3 wt% to 7 wt%. When the amount of the resin added is less than 3 wt%, the bonding force of the soft magnetic powder is insufficient, and the strength of the obtained soft magnetic composite material is lowered. When the amount of the resin added exceeds 7 wt%, the density of the soft magnetic composite material decreases.

In the elongated hole, the cornered portion has, for example, a rounded corner shape having a radius of curvature of 0.1 mm or more.

By forming the gap in this way, the corners that are easily broken in the mold have a rounded shape (in other words, a shape that is hard to break), which is suitable for improving the durability of the mold.

According to one embodiment of the present invention, there is provided a coil device having a gap hole having a shape suitable for improving the durability of a gap hole mold.

It is a perspective view of the coil device which concerns on 1st Embodiment of this invention. It is an exploded perspective view of the core provided in the coil device which concerns on 1st Embodiment of this invention. It is a front view of the core which concerns on 1st Embodiment of this invention. It is a perspective view of the mold for making the gap hole formed in the core which concerns on 1st Embodiment of this invention. FIG. 5A is a diagram showing a gap hole according to a modification 1 of the first embodiment of the present invention, and FIG. 5B is a diagram for a gap hole according to a modification 1 of the first embodiment of the present invention. It is a perspective view of a mold. FIG. 6A is a diagram showing a gap hole according to a modified example 2 of the first embodiment of the present invention, and FIG. 6B is a diagram for a gap hole according to a modified example 2 of the first embodiment of the present invention. It is a perspective view of a mold. It is a figure which shows the state of filling the gap hole of the core which concerns on 2nd Embodiment of this invention with a magnetic resin. Numerical values It is a figure which shows the DC superimposition characteristic of the coil apparatus which concerns on Example 1, 2 and Comparative Example 1. It is a front view of the core which concerns on Comparative Examples 1 and 2. It is a front view of the core which concerns on Comparative Example 3. It is a figure which shows the gap hole which concerns on the modification 3 of this invention. It is a figure which shows the gap hole which concerns on the modification 4 of this invention. It is a figure which shows the gap hole which concerns on the modification 5 of this invention. It is a figure which shows the gap hole which concerns on the modification 6 of this invention. It is a figure which shows the gap hole which concerns on the modification 7 of this invention. It is a figure which shows the gap hole which concerns on the modification 8 of this invention. It is a figure which shows the gap hole which concerns on the modification 9 of this invention. It is a front view of the core which has a gap hole outside the air core part of a coil. It is a front view of the core which has a plurality of gap holes.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same or corresponding components will be designated by the same or corresponding reference numerals, and duplicate description will be omitted.

(First Embodiment)
FIG. 1 is a perspective view of the coil device 1 according to the first embodiment of the present invention. As shown in FIG. 1, the coil device 1 includes a coil 10 and a core 20.

The coil device 1 according to the first embodiment is a reactor having a relatively large inductance value suitable for use at a low frequency, for example. The coil device 1 is not limited to the reactor, and may be another device having a coil and a core such as a transformer or an inductor.

The coil 10 is formed by spirally winding a lead wire insulated and coated with enamel or the like. As the wire rod of the conducting wire, for example, copper, aluminum, or the like is used. The coil 10 may use a winding of a round wire, or may use a flat wire such as an edgewise coil. Further, the coil 10 may be formed of a conductor in the form of a foil or a strip, such as a copper foil coil or a copper strip coil.

2 and 3 are an exploded perspective view and a front view of the core 20, respectively. As shown in FIG. 2, the core 20 has an E-shaped laminated core 20A in which a plurality of core plates 20a are laminated, and an I-shaped laminated core 20B in which a plurality of core plates 20b are laminated. Each core plate is formed by punching a plate-shaped core material with a die. The plate thickness t of each core plate is the same, and as an example, it is 0.5 mm. The laminated cores 20A and 20B are integrated by adhesion. The laminated cores 20A and 20B may be integrated by welding, or may be integrated by passing bolts through holes formed in the core plate and fastening the core plates with bolts. There may be. The laminated cores 20A and 20B may be formed by laminating core plates without adhesion. The plate thickness t of each core plate is not limited to 0.5 mm. The plate thickness t of each core plate may be 0.2 mm, 0.23 mm, 0.27 mm, 0.3 mm, or 0.35 mm. As an example, the core 20 has a width W of 48 mm and a length L of 44 mm.

The laminated core 20A has a middle leg portion 20Aa, a pair of outer leg portions 20Ab surrounding both sides thereof, and a connecting portion 20Ac connecting the middle leg portion 20Aa and the pair of outer leg portions 20Ab. The laminated core 20B has a middle leg portion 20Ba, a pair of outer leg portions 20Bb surrounding both sides thereof, and a connecting portion 20Bc connecting the middle leg portion 20Ba and the pair of outer leg portions 20Bb. In the core 20, the magnetic path of the magnetic flux generated by the coil 10 by abutting the middle leg portion 20Aa and the middle leg portion 20Ba and each outer leg portion 20Ab and each outer leg portion 20Bb (more specifically). Consists of a closed magnetic path). The abutted legs are fixed to each other by adhesion. Each leg may be fixed by welding, not limited to adhesion, or may be fixed by using a metal fitting (fixing tool).

The core 20 is not limited to the configuration of the first embodiment in which the E-shaped core and the I-shaped core are butted together, and the U-shaped core is butted against each other, and the U-shaped core and the I-shaped core are included. There may be another configuration such as a configuration in which the E-shaped cores are butted against each other and a configuration in which the E-shaped cores are butted against each other.

In the first embodiment, as the material of the laminated cores 20A and 20B, a silicon steel plate is used in consideration of the required inductance value and the material cost. For the laminated cores 20A and 20B, another material such as an amorphous ribbon may be used instead of the silicon steel plate.

A gap hole 22 is formed in the middle leg portion 20Aa. The gap hole 22 has a long hole shape that is long in a direction orthogonal to the closed magnetic path (in other words, the longitudinal direction of the middle leg portion 20Aa), and the straight hole 220 (second portion) that is long in that direction and the gap hole 22 go straight. It has a pair of round holes 222 (first portion) formed at both ends of the hole 220. In other words, the gap hole 22 has a shape in which a pair of separated round holes 222 are connected by a straight hole 220.

By forming the gap hole 22 on the closed magnetic path, magnetic saturation is less likely to occur in the coil device 1, and an inductance value can be secured even in a high current band.

The smaller the gap length G of the gap hole 22 (in other words, the width of the straight hole 220 parallel to the longitudinal direction of the middle leg portion 20Aa), the more the inductance of the coil 10 can be increased. Therefore, when the gap length G is narrowed, the volumes of the laminated cores 20A and 20B (for example, the length and width of the laminated cores 20A and 20B, the number of laminated core plates 20a and 20b) are reduced, and the number of turns of the coil 10 is reduced. Even in this case, it is easy to secure the inductance at the required rated current value. By reducing the volumes of the core plates 20a and 20b, the core 20 can be miniaturized, and the material cost of the core 20 can be suppressed at low cost. By reducing the number of turns of the coil 10, the coil device 1 can be miniaturized, and the material cost of the coil 10 can be suppressed at low cost.

Therefore, in the first embodiment, the gap length G is a value less than 1.6 times the plate thickness t of the core plate 20a. The gap length G is 0.7 mm as an example.

The gap length G may be a value within the range of 0.5 mm to less than 0.7 mm in order to secure the inductance at the rated current value while further reducing the volume of the laminated cores 20A and 20B. The gap length G may be a value wider than 0.7 mm and less than 0.8 mm.

The narrower the width of the straight hole 220, the thinner the thickness of the die for punching the straight hole 220 from the core material. Therefore, it is difficult to ensure the durability of the mold, and the mold is easily damaged.

Therefore, in the first embodiment, a pair of round holes 222 having a diameter of 1.6 times or more the plate thickness t of the core plate 20a are formed at both ends of the straight hole 220. The diameter of the round hole 222 is, for example, 1.5 mm. For convenience, the dimension of the round hole 222 that passes through the center of the round hole 222 and is parallel to the longitudinal direction of the middle leg portion 20Aa is referred to as "gap length G'". Since the diameter of the round hole 222 is 1.5 mm, the gap length G'is also 1.5 mm.

FIG. 4 is a perspective view of the die 50 for punching the gap hole 22 from the core material. As shown in FIG. 4, the mold 50 has a thin plate portion 500 corresponding to the straight hole 220. Cylindrical portions 502 corresponding to each round hole 222 are formed at both ends of the thin plate portion 500. By forming the cylindrical portion 502, the corner portions (here, both ends of the thin plate portion 500) of the thin plate portion 500 that are easily damaged are reinforced, and the durability of the mold 50 is improved.

That is, the gap hole 22 has a hole shape for thickening the corner portion of the thin plate portion 500 that is easily damaged, and has a hole shape suitable for improving the durability of the mold 50.

The gap length G'is not limited to 1.5 mm, and may be another value of 1.6 times or more (that is, 0.8 mm or more) of the plate thickness t of the core plate 20a. By setting the gap length G'to 1.6 times or more the plate thickness t, the metal corresponding to the cylindrical portion 502 (in other words, the round hole 222 (first portion) of the gap hole 22) corresponding to the gap length G'. A sufficient thickness of the mold 50 portion) can be secured. As a result, the durability of the mold 50, which is concerned about a decrease in durability due to having a thin-walled portion (specifically, a thin plate portion 500 having a width of less than 1.6 times the plate thickness t) which is the second portion. The property is improved, and it is possible to prevent the mold 50 from being bent or bent. More specifically, since the columnar portion 502 plays a role of reinforcing the entire mold 50, it is possible to prevent the mold 50 from being bent or bent even when the mold 50 has a thin portion.

On the other hand, when the gap length G'is less than 1.6 times the plate thickness t of the core plate 20a, the thickness of the cylindrical portion 502 cannot be sufficiently secured, and the durability of the mold 50 is sufficiently improved. I can't let you. Therefore, the die 50 is likely to be bent or bent due to the repeated load received by the die 50 when the core plate 20a is punched out.

If the die 50 has an acute-angled portion, that portion is likely to be chipped due to the repeated load received by the die 50 when punching the core plate 20a. Therefore, the connecting portion (in other words, the cornered portion) between the straight hole 220 and the round hole 222 has a rounded corner shape with a radius of curvature of 0.1 mm. As a result, the gap hole 22 has a hole shape that does not have a portion having an acute angle. By forming the gap hole 22 in this way, the mold 50, which has a concern that the durability may be lowered due to the thin plate shape, can be formed into a shape having no acute-angled portion. Such a shape of the gap hole 22 improves the durability of the mold 50 because the acute-angled portion that is particularly liable to be damaged due to the thin plate shape can be eliminated from the mold 50 (in other words, the above repetition). It is suitable for preventing the loss of acute-angled parts due to load).

The connecting portion between the straight hole 220 and the round hole 222 may have a rounded corner shape having a radius of curvature exceeding 0.1 mm. In this case, since the corners of the mold 50 can be made into a more rounded shape, it is more suitable for improving the durability of the mold 50.

The gap hole 22 is not limited to the shape shown in FIG. 3, and may have another shape.

FIG. 5A is a diagram showing the shape of the gap hole 22v1 according to the first modification. FIG. 5B is a perspective view of the mold 50v1 for the gap hole 22v1 of the present modification 1.

In the present modification 1, as shown in FIG. 5A, a round hole 222 is also formed in the center of the gap hole 22v1. As shown in FIG. 5B, in the mold 50v1, the columnar portions 502 are formed at equal intervals, and the durability thereof is improved.

FIG. 6A is a diagram showing the shape of the gap hole 22v2 according to the second modification. FIG. 6B is a perspective view of the mold 50v2 for the gap hole 22v2 of the second modification.

As shown in FIG. 6A, a square hole 222 ”is formed in the gap hole 22v2 according to the present modification 2 instead of the round hole 222. As shown in FIG. 6B, the gap hole 22v2 is formed. Square pillars 502 "corresponding to each square hole 222" are formed at both ends of the thin plate portion 500. The prismatic portion 502 "has a square pillar shape, and one side is 1.5 mm, which is larger than the gap length G. It has become. Also in this modification 2, the corners of the thin plate portion 500, which is easily damaged, are reinforced, and the durability of the mold 50v2 is improved.

In order to improve the durability of the mold 50v2, the connecting portion between the straight hole 220 and the square hole 222 ”is also rounded with a radius of curvature of 0.1 mm, as in the first embodiment. The four corners of the square hole 222 "are also rounded with a radius of curvature of 0.1 mm.

The gap hole 22 according to the first embodiment is an acute-angled hole formed in the core 20, and has a gap length G'that is 1.6 times or more the plate thickness t of the core plate 20a in the first portion including both ends thereof. The second portion other than the first portion has a gap length G of less than 1.6 times the plate thickness t of the core plate 20a, and has a hole shape having no acute-angled portion. By making the shape of the gap hole 22 having no acute-angled portion, the mold 50 also has a shape having no acute-angled portion. Therefore, while realizing a narrow gap length G, the durability of the mold 50 for obtaining the gap length G is improved.

As shown in FIG. 1, the middle leg portion 20Aa is inserted into the air core portion of the coil 10. Therefore, the gap hole 22 is arranged in the air core portion of the coil 10. By arranging the gap hole 22 in the air core portion of the coil 10, the leakage flux from the gap hole 22 is reduced as compared with the case where the gap hole 22 is arranged outside the air core portion of the coil 10.

The gap hole 22 may be arranged outside the air core portion of the coil 10. In this case, the gap holes 22 are formed at any one or more of the outer leg portions 20Ab and 20Bb and the connecting portions 20Ac and 20Bc. FIG. 18 shows an example in which the gap hole 22 is arranged outside the air core portion of the coil 10. In the example of FIG. 18, one gap hole 22 is formed in each outer leg portion 20Ab.

Magnetic flux flows intensively through both sides 20Ad of the gap hole 22, and the core 20 tends to generate heat. Therefore, as shown in FIG. 19, the core 20 may have a plurality of gap holes 22 (two in the example of FIG. 19), not limited to one. In this case, the gap length G of each gap hole 22 is designed to be narrower than the gap length G when there is one gap hole 22 so that the effective magnetic permeability is equivalent to that of one gap hole 22. By dividing one gap hole 22 into a plurality of narrower gap holes 22, the concentration of magnetic flux is relaxed (dispersed), and heat generation of the core 20 is suppressed.

The gap length G is preferably a value of 0.7 times or more the plate thickness t of the core plate 20a in order to secure the durability of the entire thin plate portion 500. By setting the gap length G to 0.7 times or more the plate thickness t, even when the core plate 20a has a large number of punching cycles (that is, the number of core plates 20a punched by the die 50 per unit time is large). It is possible to prevent the mold 50 from being deformed or damaged. On the other hand, if the gap length G is less than 0.7 times the plate thickness t, if the core plate 20a has many punching cycles, the thin plate portion 500 may be bent or bent due to the repeated load received by the die 50. There is.

(Second Embodiment)
The gap hole 22 of the core 20 according to the second embodiment is filled with a magnetic resin 30 obtained by adding a resin to the magnetic powder. FIG. 7 shows how the magnetic resin 30 is filled in the gap hole 22 of the core 20 according to the second embodiment. The coil device according to the second embodiment has the same configuration as the coil device 1 according to the first embodiment, except that the gap hole 22 is filled with the hardened magnetic resin 30.

The magnetic resin 30 is, for example, a material in which magnetic powder (more specifically, soft magnetic powder) is dispersed in a resin material. Examples of the resin material used for the magnetic resin 30 include materials that can be cured from a liquid state to a solid state, such as a thermosetting resin, an ultraviolet curable resin, and a thermoplastic resin. The soft magnetic powder used in the magnetic resin 30 includes, for example, pure iron, Fe-Si, Fe-Ni, Fe-Al, Fe-Co, Fe-Cr, Fe-N, Fe-C, Fe-B, and the like. Examples thereof include Fe-based alloy powders such as Fe-P and Fe-Al-Si, rare earth metal powders, amorphous metal powders, ferrite powders, and the like, or a mixture of a plurality of types of powders.

The amount of the resin added to the soft magnetic powder is in the range of 3 wt% to 7 wt%. When the amount of the resin added is less than 3 wt%, the bonding force of the soft magnetic powder is insufficient, and the strength of the obtained soft magnetic composite material is lowered. When the amount of the resin added exceeds 7 wt%, the density of the soft magnetic composite material decreases.

The magnetic resin 30 has a high content of soft magnetic powder in order to improve the effective magnetic permeability, and is in a liquid state having a relatively high viscosity before being cured. Consider, for example, a case where the magnetic resin 30 is uniformly applied into the gap holes 22 at the time of manufacturing. In this case, since the magnetic resin 30 has a high viscosity, it is difficult to uniformly apply the magnetic resin 30 in the gap holes 22.

Therefore, in the second embodiment, the step of filling the gap hole 22 with the magnetic resin 30 is adopted. The gap hole 22 that defines the space surrounded on all sides is easily filled with the magnetic resin 30 by uniformly pouring it.

As shown in FIG. 7, the magnetic resin 30 is injected into the gap hole 22 using a jig 60 (specifically, a syringe filled with the magnetic resin 30). As shown in FIG. 7, the round hole 222 has a size that allows the injection port 62 of the jig 60 to be securely inserted. Even when the injection port 62 does not enter the straight hole 220 due to the narrow width of the straight hole 220 (that is, the gap length G), the magnetic resin 30 can be reliably injected into the gap hole 22 from the round hole 222. That is, in the second embodiment, it is not necessary to consider the size of the injection port 62 when setting the gap length G.

The effective magnetic permeability changes according to the gap length G. However, the effective magnetic permeability may not be set to a desired value only by the gap length G alone. In the second embodiment, the effective magnetic permeability is finely adjusted to match a desired value by filling the gap holes 22 with the magnetic resin 30. By finely adjusting the effective magnetic permeability to match the desired value, for example, a DC superimposition characteristic that makes magnetic saturation less likely to occur can be obtained.

By filling the gap hole 22 with the magnetic resin 30, the rigidity of the core 20 around the gap hole 22 is improved. Therefore, the vibration of the core 20 due to the electromagnetic attraction generated in the gap hole 22 and the noise caused by this vibration can be suppressed to a small extent.

Further, by filling the gap hole 22 with the magnetic resin 30, the leakage flux from the gap hole 22 is reduced, and the occurrence of eddy current loss in the coil 10 is reduced. For example, when the coil device 1 is mounted on a three-phase reactor, the leakage flux from the gap hole 22 is reduced, so that the variation in the characteristics of each phase due to the manufacturing error of each leg of the core 20 can be suppressed.

Further, in the case of a three-phase reactor in which the gap completely divides the core (see, for example, FIGS. 9 and 10 described later), various variations are accumulated in the process of combining a plurality of cores (for example, the gap length). Variations are the accumulation of variations in core dimensions and assembly), and the characteristics of each phase are likely to vary. On the other hand, when the gap hole 22 that does not completely divide the core is adopted as in the second embodiment (and the first embodiment), the variation in the gap length depends only on the dimensional accuracy of the gap hole 22. It is easier to suppress variations in the characteristics of each phase compared to the form in which the gap completely divides the core.

Further, by filling the gap hole 22 with the magnetic resin 30, magnetic flux also flows in the gap hole 22 (in other words, the magnetic resin 30). Therefore, the concentration of the magnetic flux flowing through both sides 20Ad of the gap hole 22 is relaxed, and the heat generation of the core 20 is suppressed.

(Experimental data)
FIG. 8 is a diagram showing DC superimposition characteristics of the coil device according to Numerical Examples 1 and 2 and Comparative Example 1. In FIG. 8, the vertical axis represents inductance (unit: mH), and the horizontal axis represents current (unit: A).

Numerical values In each of the coil devices according to Examples 1 and 2 and Comparative Example 1, the number of coil turns is 70. These coil devices have the same configuration except that the shape of the core is different.

Numerical values Each of the cores according to Examples 1 and 2 and Comparative Example 1 has a laminated core in which core plates (electromagnetic steel plates) having a thickness of 0.5 mm are laminated.

FIG. 9 shows a front view of the core 120 according to Comparative Example 1 (and the core 122 according to Comparative Example 2 described later). The core 120 according to Comparative Example 1 is an EI60 (width W: 60 mm, length L: 50 mm) core conforming to the JEITA standard (RC-2724A), has a laminated thickness of 20.5 mm, and has a gap of G1. The length is 1.2 mm. Further, the core 120 according to Comparative Example 1 has a weight of 379 g.

Numerical values The core according to the first embodiment has the same configuration as the core 20 according to the first embodiment, has a laminated thickness of 24.0 mm, and has a gap length G of 0.7 mm. Numerical values The core according to the first embodiment has a width W of 48 mm and a length L of 44 mm. The core according to the numerical embodiment 1 has a weight of 302 g. That is, the difference between the core according to the numerical embodiment 1 and the core 120 according to the comparative example 1 is the volume of the core, the gap position, and the gap length.

Numerical values The core according to the second embodiment has the same configuration as the core 20 according to the second embodiment, has a laminated thickness of 20.5 mm, a gap length G of 0.7 mm, and a weight of 258 g. The core according to Numerical Example 2 has the same configuration as the core according to Numerical Example 1 except that the laminated thickness is 20.5 mm and the gap hole 22 is filled with the magnetic resin 30.

Numerical values In Examples 1 and 2, even when the volume of the core is reduced (in other words, the core is miniaturized) as compared with Comparative Example 1 by narrowing the gap length G, as shown in FIG. In addition, a large inductance value is secured (especially in a small current band of 6 A or less). Numerical values In Examples 1 and 2, although a large inductance value is secured in the small current band, an inductance value equivalent to that in Comparative Example 1 is secured even in a large current band of 10 A or more.

In Numerical Example 2, the inductance value is further improved as compared with Numerical Example 1 by filling the gap hole 22 with the magnetic resin 30. Therefore, in Numerical Example 2, the volume of the core (specifically, the number of stacked cores) can be reduced as compared with Numerical Example 1 to reduce the size of the core.

Next, the noise generated in the coil device will be described with reference to Numerical Examples 1 and 2 and Comparative Examples 2 and 3.

Numerical values The noise generated in each of the coil devices of Examples 1 and 2 and Comparative Examples 2 and 3 was measured under the following conditions.

The coil device was placed on a wooden stand installed in an anechoic box so that the longitudinal direction of each leg was vertical. A microphone was installed at an upper position of the coil device, 55 mm away from the center of the upper surface of the coil device. A 50 Hz sine wave waveform overlaid with specified noise was input to the coil device 1. The current value passed at this time was 10 A.

The coil device according to Comparative Examples 2 and 3 also has a laminated core in which the number of coil turns is 70 and a core plate (electromagnetic steel plate) having a plate thickness of 0.5 mm is laminated.

The core 122 according to Comparative Example 2 has a laminated thickness of 20.5 mm and a gap length of the gap G2 of 1.0 mm. The core 122 according to Comparative Example 2 has the same width W and length L as the core according to Numerical Example 1, and the widths of the middle leg portion, the outer leg portion, and the connecting portion are also numerical values. Is the same as.

FIG. 10 shows a front view of the core 124 according to Comparative Example 3. The core 124 according to Comparative Example 3 has a laminated thickness of 20.5 mm and a gap length of the gap G3 of 1.0 mm. The core 124 according to Comparative Example 3 has the same width W and length L as the core according to Numerical Example 1, and the widths of the middle leg portion, the outer leg portion, and the connecting portion are also numerical values. Is the same as. As shown in FIG. 10, in the core 124 according to Comparative Example 3, the gap G3 is formed at the center position of the core 124. The only substantial difference between the core 122 according to Comparative Example 2 and the core 124 according to Comparative Example 3 is the gap position.

Numerical values The noise measured by each of the coil devices of Examples 1 and 2 and Comparative Examples 2 and 3 is shown below.

Numerical Example 1: 54.0 dB
Numerical Example 2: 52.2 dB
Comparative Example 2: 61.8 dB
Comparative Example 3: 62.0 dB

Comparing Comparative Example 2 and Comparative Example 3, it was found that there is no substantial difference in noise depending on the difference in the gap position.

Comparing the numerical example 1 with the comparative example 2 or 3, it was obtained that the numerical example 1 had a clearly smaller noise.

In Comparative Examples 2 and 3, the middle leg portion of the core is completely divided at the gap, and the rigidity of the core becomes low in the vicinity of this divided portion (that is, the end portions of the cores facing each other through the gap). There is. Therefore, the vicinity of this divided portion vibrates mainly due to the electromagnetic attraction generated in the gap, and noise is generated along with this vibration. On the other hand, in Numerical Example 1, the middle leg portion of the core is not completely divided by the gap hole 22, and the decrease in rigidity in the vicinity of the gap hole 22 is smaller than that in Comparative Examples 2 and 3. Therefore, the vibration of the core due to the electromagnetic attraction generated in the gap hole 22 is small, and the noise associated with this vibration is small.

In Numerical Example 2, since the gap hole 22 is filled with the magnetic resin 30, the rigidity of the core 20 around the gap hole 22 is further improved as compared with Numerical Example 1. Therefore, the vibration of the core 20 due to the electromagnetic attraction generated in the gap hole 22 and the noise caused by this vibration are further suppressed.

The above is the description of the embodiment of the present invention, but the present invention is not limited to the configuration of the above-described embodiment, and various modifications can be made within the scope of the technical idea thereof. For example, an embodiment of the present invention also includes an appropriate combination of at least a part of the technical configurations of one or more embodiments described in the specification and a well-known technical configuration.

In the second embodiment, the injection port 62 of the jig 60 is inserted into the round hole 222 to fill the gap hole 22 with the magnetic resin 30, but in another embodiment, the injection port 62 is above the round hole 222. The magnetic resin 30 may be poured into the gap hole 22 from the injection port 62 installed above the round hole 222 to fill the gap hole 22.

In the second embodiment, the magnetic resin 30 is filled in the gap hole 22, but in another embodiment, a resin containing no soft magnetic powder may be filled in the gap hole 22. With a resin that does not contain soft magnetic powder, the effective magnetic permeability and DC superimposition characteristics cannot be adjusted or the leakage flux from the gap hole 22 cannot be reduced, but the rigidity of the core 20 around the gap hole 22 is improved. The vibration of the core 20 due to the electromagnetic attraction generated in the gap hole 22 and the noise caused by this vibration can be suppressed to a small extent.

Further modified examples 3 to 9 of the gap hole 22 are shown in FIGS. 11 to 17.

As shown in FIG. 11, the gap hole 22v3 according to the modified example 3 has a gap length G (and G') 1.6 times the plate thickness t of the core plate 20a over the entire gap hole 22v3. Both ends of the gap hole 22v3 have a shape having a radius of curvature that is 0.8 times the plate thickness t. That is, the gap hole 22v3 has a hole shape in which the first portion and the second portion of the elongated hole have the same width and do not have a portion having an acute angle. Therefore, the gap hole 22v3 according to the modified example 3 also has a shape suitable for improving the durability of the mold.

As shown in FIG. 12, the gap hole 22v4 according to the modified example 4 has a shape in which a pair of square holes 222 "are formed at both ends of the straight hole 220. In the modified example 4, the straight hole 220 is formed. The core plate 20a has a gap length G of less than 1.6 times the plate thickness t. Further, in the modified example 4, the square hole 222 ”is orthogonal to a side of 1.6 times or more of the plate thickness t and this side. Moreover, it has a side longer than this side (in other words, a side having a gap length G'). The square hole 222 ”has a size that accommodates a circle having a diameter of 1.6 times or more the plate thickness t, has a rounded corner shape with four corners having a radius of curvature of 0.1 mm, and is connected to the straight hole 220. The portion also has a rounded corner shape with a radius of curvature of 0.1 mm. The gap hole 22v4 according to the modified example 4 does not have a portion having a sharp angle, and has a shape suitable for improving the durability of the mold. There is.

For example, the gap hole 22 according to the first embodiment has a wide gap length G'at both ends. On the other hand, the gap hole 22v5 according to the modified example 5 shown in FIG. 13 has a wide gap length G'in addition to both ends thereof. Specifically, the gap hole 22v5 according to the modified example 5 is formed in a diamond shape. The gap hole 22v5 has a wide gap length G'(for example, 1.6 to 4 times the plate thickness t of the core plate 20a) in the central portion thereof, and a narrow gap length G'at both ends thereof (exemplary). It has less than 1.6 times the plate thickness t). The gap hole 22v5 according to the modified example 5 has rounded corners at the four corners of the rhombus, does not have an acute-angled portion, and has a shape suitable for improving the durability of the mold.

The shape of the straight hole 220, which is long in the direction orthogonal to the closed magnetic path, is not limited to the one having a constant width, and even if the width changes continuously like the gap hole 22v6 according to the modified example 6. Good (see Figure 14).

For example, the gap hole 22 according to the first embodiment has a long hole shape that is long in a direction orthogonal to the closed magnetic path, but may have a long long hole shape in a direction that is not orthogonal to the closed magnetic path. As an example of such a gap hole, a V-shaped shape (gap hole 22v7 according to the modified example 7 shown in FIG. 15), an N-shaped shape (gap hole 22v8 according to the modified example 8 shown in FIG. 16), and an oblique line. The shape (gap hole 22v9 according to the modified example 9 shown in FIG. 17) can be mentioned.

1 Coil device 10 Coil 20 Core 20a, 20b Core plate 20A, 20B Laminated core 20Aa, 20Ba Middle leg 20Ab, 20Bb Outer leg 20Ac, 20Bc Connecting 22 Gap hole 30 Magnetic resin 50 Mold 60 Jig 62 Injection 220 Straight hole 222 Round hole 500 Thin plate part 502 Cylindrical part

Claims (8)

In a coil device including a coil and a core forming a magnetic path of the magnetic flux generated by the coil, and a gap is formed on the magnetic path.
The core is
It is a laminated core in which multiple core plates are laminated.
The gap is
It is an elongated hole formed in the core.
The first portion of the elongated hole has a gap length of 1.6 times or more the plate thickness of the core plate.
The second portion of the elongated hole other than the first portion has a gap length of 1.6 times or less the plate thickness of the core plate.
The elongated hole has a hole shape that does not have an acute-angled portion.
Coil device. The elongated hole is
The second portion has a gap length of less than 1.6 times the plate thickness of the core plate.
The coil device according to claim 1. The first part is
Including both ends of the elongated hole,
The coil device according to claim 1 or 2. A part of the core is inserted into the air core portion of the coil.
The gap is
Arranged in the air core
The coil device according to any one of claims 1 to 3. The hole shape of the gap is
A straight hole having a width of less than 1.6 times the plate thickness of the core plate, and
A pair of round holes formed at both ends of the straight hole and having a diameter of 1.6 times or more the plate thickness of the core plate,
Have,
The coil device according to any one of claims 1 to 4. The gap is filled with a magnetic resin obtained by adding a resin to a soft magnetic powder.
The coil device according to any one of claims 1 to 5. The magnetic resin is
The amount of the resin added to the soft magnetic powder is in the range of 3 wt% to 7 wt%.
The coil device according to claim 6. In the elongated hole, the corner portion has a rounded corner shape having a radius of curvature of 0.1 mm or more.
The coil device according to any one of claims 1 to 7.

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