JP7699442B2 - Reactor - Google Patents

Description

The present invention relates to a reactor having a core and a coil.

Reactors are used in a variety of applications, including office equipment, solar power generation systems, automobiles, and uninterruptible power supplies. A reactor primarily consists of a coil, core, and resin parts. When electricity is passed through the coil, it generates magnetic flux according to the number of turns, and the core acts as a magnetic path through which the magnetic flux generated by the coil passes. A reactor is an electromagnetic component that converts electrical energy into magnetic energy and stores and releases it. The resin parts insulate the coil and core.

One known example of such a reactor is a double-molded reactor, in which a first molding process is performed to integrate the core and resin member, which is then attached to the coil, and a second molding process is performed to integrate the core and coil with the resin member. Alternatively, the core and coil are molded separately, and the core integrated with the resin member is pressed into the inner circumference of a cylindrical coil to integrate the coil and core.

JP 2013-149841 A JP 2012-028572 A

The coil vibrates due to magnetic attraction, and the core vibrates due to magnetostriction. This causes the reactor to vibrate. By integrating the core and coil as described above, a certain degree of effect was achieved in suppressing the vibration of the reactor. However, when integrated, the core and coil are connected via a resin member, so the vibration of the coil and the vibration of the core are transmitted to each other. As a result, the vibration of the coil and the vibration of the core resonate, leading to increased vibration of the reactor. In recent years, as the applications of reactors have become more diverse, there has been a demand for even greater vibration reduction.

The present invention was made to solve the above problems, and its purpose is to obtain a reactor that suppresses the propagation of coil vibration and core vibration and reduces vibration.

To solve the above problems, the reactor of the present invention is characterized in that it comprises a cylindrical coil and a core having legs around which the coil is wound, the legs are not in contact with the inner circumferential surface of the coil over the entire surface, and a gap is provided between the legs and the inner circumferential surface of the coil over the entire surface.

It is possible to obtain a reactor that can suppress the propagation of core vibration and coil vibration and reduce vibration.

1 is a perspective view showing an overall configuration of a reactor according to an embodiment; FIG. 2 is a top perspective view showing the overall configuration of a molded core. FIG. 2 is a bottom perspective view showing the overall configuration of a molded core. FIG. 2 is a bottom perspective view of the molded coil. 2 is a cross-sectional view taken along line AA of FIG. 1. FIG. 2 is an enlarged view of the portion circled by the dashed line in FIG. 1 . 13 is a diagram showing the positional relationship between the leg portion and the inner surface covering portion according to the modified example. FIG.

(Embodiment)
A reactor according to an embodiment will be described with reference to the drawings. In each drawing, dimensions, positional relationships, ratios, shapes, etc. may be emphasized for ease of understanding, but the present invention is not limited to such emphasis. Fig. 1 is a perspective view showing the overall configuration of the reactor. Fig. 2 is a top perspective view showing the overall configuration of a molded core. Fig. 3 is a bottom perspective view showing the overall configuration of a molded core. Fig. 4 is a bottom perspective view of a molded coil.

The reactor 10 is an electromagnetic component that converts electrical energy into magnetic energy and stores and releases it, and is used in a variety of applications, such as office equipment, solar power generation systems, and automobiles. The reactor 10 of this embodiment includes a core 1, a core mold resin 2, a coil 3, and a coil mold resin 4.

The core 1 can be a dust core, a ferrite core, a laminated steel plate, a metal composite core, or the like. A metal composite core is a magnetic body made by kneading magnetic powder and resin and then hardening the resin.

The core 1 is made of a U-shaped core member 11 having a pair of legs 12 and a yoke portion 13 that connects the pair of legs 12. Two U-shaped core members 11 are provided. The core 1 is formed into an annular shape by bonding the legs 12 of the U-shaped core members 11 together with an adhesive. The coil 3 is attached to the legs 12.

In this embodiment, the legs 12 of the U-shaped core member 11 are joined via a spacer 14. The spacer 14 can be made of a non-magnetic material, ceramic, non-metal, resin, carbon fiber, or a composite material of two or more of these, or gap paper. In this way, by joining the U-shaped core member 11 via the spacer 14, a magnetic gap of a predetermined width is provided, preventing a decrease in inductance of the reactor. Alternatively, an air gap may be provided without using the spacer 14, or the U-shaped core member 11 may be directly joined with an adhesive without providing a gap.

The core mold resin 2 is a resin member that covers the surface of the core 1. This core mold resin 2 is molded integrally with the core 1 by molding. Examples of the type of resin include epoxy resin, unsaturated polyester resin, urethane resin, BMC (Bulk Molding Compound), PPS (Polyphenyl Sulfide), PBT (Polybutylene Terephthalate), and a combination of these. A thermally conductive filler may be mixed into the resin.

In this embodiment, the core mold resin 2 covers only the yoke portion 13 of the core 1. In other words, the leg portion 12 of the core 1 is not covered by the core mold resin 2 and is exposed. The core mold resin 2 has a bottom opening 21. The bottom opening 21 is located on the bottom surface of the yoke portion 13, and the bottom surface of the yoke portion 13 is exposed. A heat dissipation member such as a heat dissipation sheet is provided on this exposed bottom surface of the yoke portion 13, and the bottom surface of the yoke portion 13 and the heat dissipation member are in contact. The bottom surface of the yoke portion 13 refers to the end surface of the yoke portion 13 that faces the installation surface on which the reactor 10 is installed.

The core mold resin 2 has a core holding portion (not shown) that holds the core 1. The core holding portion is provided, for example, at both ends of the long side of the yoke portion 13, and the core holding portion and the object to be installed are fastened by bolts or the like. This fixes the core 1 in the desired position.

The coil 3 is composed of a single rectangular conductive member that is insulated with enamel or the like. The coil 3 is formed by winding the conductive member into a cylindrical shape while shifting the winding position in the winding axis direction. In this embodiment, the coil 3 is an edgewise coil of rectangular wire made of copper wire. Note that the type of wire material and the winding method of the coil 3 are not limited to this, and other shapes may also be used.

The end of coil 3 is electrically connected to an external device. When power is supplied from the external device, a current flows through coil 3, generating magnetic flux, which then flows through core 1, forming a closed magnetic circuit.

As shown in FIG. 4, the coil mold resin 4 is a resin member that covers the surface of the coil 3. This coil mold resin 4 is molded integrally with the coil 3 by molding. The type of resin that can be used is the same as that of the core mold resin 2.

The coil mold resin 4 covers the outer and inner surfaces of the coil 3. The coil mold resin 4 has an outer surface coating portion 41 that coats the outer surface of the coil 3, and an inner surface coating portion 42 that coats the inner surface of the coil 3. The inner surface coating portion 42 insulates the coil 3 from the leg portion 12.

The outer covering portion 41 does not cover the bottom surface of the coil 3, and the coil 3 is exposed. In other words, the outer covering portion 41 has a bottom opening 43 that exposes the bottom surface of the coil 3. The bottom surface of the coil 3 is provided with an elastic heat dissipation member such as a heat dissipation sheet, heat dissipation grease, or heat dissipation gap filler (a material that is in a paste form when applied and becomes elastic when hardened into a sheet), and the exposed bottom surface of the coil 3 and the heat dissipation member are in contact. The bottom surface of the coil 3 refers to the end surface of the coil 3 that faces the installation surface on which the reactor 10 is installed.

The outer surface covering portion 41 has a coil holding portion (not shown) that holds the coil 3. The coil holding portion is fastened to the installation object by, for example, a bolt or the like. This fixes the coil 3 in the desired position. The coil holding portion and the core holding portion are provided separately and independently, so the core 1 is held and fixed separately and independently from the coil 3.

Figure 5 is a cross-sectional view taken along line A-A in Figure 1. As shown in Figure 5, the inner covering portion 42 has a rectangular cross section. The inner covering portion 42 is held by the coil holding portion without contacting the leg portion 12. That is, a gap S is provided between the inner covering portion 42 and the leg portion 12. More specifically, the gap S is provided without all four faces of the leg portion 12 having a rectangular cross section coming into contact with the coil molded resin 4. That is, the outer diameter of the leg portion 12 is smaller than the inner diameter of the coil 3. In this embodiment, the gap S between the leg portion 12 and the inner covering portion 42 on each face is approximately the same. A notch 44 is provided in the center of each face of the inner covering portion 42.

Figure 6 is an enlarged view of the dotted circle in Figure 1. As shown in Figure 6, a gap is provided between the core mold resin 2 that covers the yoke portion 13 of the core 1 and the end face of the outer surface coating portion 41 that is perpendicular to the winding axis direction of the coil 3. In other words, the core mold resin 2 and the outer surface coating portion 41 are not in contact.

As described above, the reactor 10 of this embodiment includes the coil 3 and the core 1 having the leg portion 12 around which the coil 3 is wound. The core 1 has the core mold resin 2 that covers the yoke portion 13 and a core holding portion that holds the core 1, and the coil 3 has an inner surface covering portion 41 that covers the inner surface of the coil 3 and a coil holding portion that holds the coil 3. The leg portion 12 and the inner surface covering portion 42 do not come into contact with each other, and a gap is provided between the leg portion 12 and the inner surface covering portion 42 over the entire surface.

Conventionally, the vibration of a reactor has been reduced by attaching a resin-molded core to a coil, and then further molding the core and coil together in resin. However, when the core and coil are integrated, they are connected via resin, and the vibration caused by the magnetic attraction of the coil and the vibration caused by magnetostriction of the core propagate to each other and resonate, resulting in increased vibration of the reactor.

However, in the reactor 10 of this embodiment, the core 1 and the coil 3 are held independently, and a gap is provided between the legs 12 of the core 1 and the inner surface covering portion 41, so that the core 1 and the coil 3 are not in contact with each other. This makes it possible to suppress the vibration caused by the magnetic attraction force of the coil and the vibration caused by magnetostriction of the core from propagating to each other, and therefore it is possible to suppress the vibration of the reactor 10 more effectively than in a reactor in which the coil 3 and the core 1 are integrated.

The core 1 has a plurality of legs 12, a yoke portion 13 that connects the legs 12, and a core mold resin 2 that covers the yoke portion 13. A gap is provided between the core mold resin 2 that covers the yoke portion 13 and the end face of the outer cover portion 41 that is perpendicular to the winding axis direction of the coil. This makes it possible to suppress the propagation of vibrations between the yoke portion 13 and the coil 3, thereby further enhancing the vibration suppression effect of the reactor 10.

The bottom surface of the yoke portion 13 is exposed and not covered by the core mold resin 2. Because the core 1 and the coil 3 are not connected, it is difficult to dissipate the heat of the core 1 to the outside via the coil 3. Therefore, by exposing the bottom surface of the yoke portion 13, the heat of the core 1 can be dissipated to the outside from the bottom surface of the yoke portion 13. In particular, as in this embodiment, by arranging a heat dissipation member so that it abuts against the exposed bottom surface of the yoke portion 13, the heat of the core 1 can be effectively dissipated to the outside. This improves the heat dissipation performance of the reactor 10.

The core 1 is made up of a pair of U-shaped core members 11, which are bonded together with an adhesive. This makes it possible to suppress the vibration of the core 1 itself, and therefore the vibration of the reactor 10.

The inner covering portion 42 is provided with a notch 44. The reactor 10 may be installed in a place where vibration occurs, such as in a vehicle. If the reactor 10 is installed in such a place, the reactor 10 vibrates due to the external environment, and the position of the leg 12 or the coil 3 may be shifted due to the vibration caused by the external environment, and the leg 12 may come into contact with the inner covering portion 42. Therefore, by providing the notch 44 in the inner covering portion 42, even if the position of the leg 12 or the coil 3 is shifted due to the vibration caused by the external environment and the leg 12 and the inner covering portion 42 come into contact with each other, the contact area between the leg 12 and the inner covering portion 42 can be reduced by providing the notch 44 in the inner covering portion 42. Therefore, even if the reactor 10 is installed in a place where vibration occurs, the propagation of vibration between the core 1 and the coil 3 can be minimized, and the vibration of the reactor 10 can be suppressed.

(Modification)
Next, a modified reactor 10 will be described with reference to the drawings. Note that the same reference numerals are used to designate the same configurations and functions as those in the embodiment, and detailed descriptions are omitted. Only the differences will be described.

In the reactor 10 according to the modified example, there is no gap between the leg 12 and the inner surface coating 42 over the entire surface. As shown in FIG. 7, only the lower surface of the leg 12 is in contact with the inner surface coating 42. That is, the coil 3 is sandwiched between the heat dissipation member and the lower surface of the leg 12. In other words, there is a gap other than between the lower surface of the leg 12 and the inner surface coating 42.

The coil 3 is held by being sandwiched between the lower surface of the leg 12 of the core 1 fixed by the core holding portion and the heat dissipation member, and the coil 3 does not contact the installation surface of the reactor 10. In other words, as in the above embodiment, the outer surface covering portion 41 does not have a coil holding portion that holds the coil 3 by fastening it to the installation surface with a bolt or the like. In this way, the coil holding portion also includes a form in which the coil 3 is held by being sandwiched between the lower surface of the leg 12 and the heat dissipation member.

In this way, if only the lower surface of the leg 12 is in contact with the inner coating 42, the vibration of the reactor 10 can be reduced without affecting the propagation of vibration. Also, since the coil 3 is in contact with an elastic heat dissipation member, the vibration of the coil 3 can be suppressed by the heat dissipation member. Furthermore, by bringing the lower surface of the leg 12 into contact with the inner coating 42, the heat of the core 1 can be transferred from the lower surface of the leg 12 through the inner coating 42 and the coil 3 to the heat dissipation member provided on the bottom surface of the coil 3. Therefore, heat is not trapped in the leg 12, and the heat dissipation performance of the reactor 10 can be improved while obtaining a vibration suppression effect.

In particular, the coil 3 is sandwiched between the heat dissipation member and the underside of the leg 12. This further suppresses the vibration of the coil 3 itself. As a result, even if the vibration is transmitted to the core 1, the vibration of the reactor 10 can be kept to a minimum.

The end surface of the inner surface coating portion 42 that comes into contact with the underside of the leg portion 12 does not need to have a notch 44. This expands the heat dissipation path from the underside of the leg portion 12, thereby further improving the heat dissipation performance of the reactor 10.

Other Embodiments
In this specification, an embodiment of the present invention has been described, but this embodiment is presented as an example and is not intended to limit the scope of the invention. The above-mentioned embodiment can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the scope of the invention. The embodiment and its modifications are included in the scope of the invention and its equivalents described in the claims, as well as in the scope and gist of the invention.

In the embodiment, the coil is fixed and positioned by fastening the coil holding portion with a screw such as a bolt, but the coil holding portion may have any configuration as long as it can hold the coil 3. For example, the coil 3 may be fixed by fitting the coil holding portion to a heat dissipation member provided on the bottom surface of the coil 3. That is, the coil 3 may be in contact with the heat dissipation member and not in contact with the installation surface of the reactor 10. In this case, the heat dissipation member and the exposed bottom surface of the coil 3 are in contact, so that the heat of the coil 3 can be released to the heat dissipation member, improving the heat dissipation of the reactor 10. In addition, since the coil 3 is not in contact with the installation surface, the propagation of vibrations of the coil 3 and the core 1 through the core holding portion and the installation surface can be prevented, and a better vibration suppression effect can be obtained.

In addition, the core mold resin 2 does not have to have a core holding portion, and the coil mold resin 4 does not have to have a coil holding portion. As long as a gap can be formed between the leg portion 12 and the inner surface of the coil 3, any method of fixing the core 1 and the coil 3 may be used. For example, a fixing mechanism may be provided on the object on which the reactor 10 is to be installed, and the core 1 and the coil 3 may be fitted and fixed thereto.

In the embodiment, the legs 12 of the core 1 are exposed and not covered with the core mold resin 2, but the legs 12 may also be covered with the core mold resin 2 like the yoke portion 13. It is easier to mold the legs 12 so that they are covered with the core mold resin 2 along with the yoke portion 13, improving productivity.

In addition, when the legs 12 are covered with the core mold resin 2, the inner surface of the coil 3 may be exposed without being covered by the inner surface covering part 42. Even in this case, the legs 12 (core 1) and the coil 3 can be insulated by the core mold resin 2.

REFERENCE SIGNS LIST 10 Reactor 1 Core 11 U-shaped core member 12 Leg 13 Yoke 14 Spacer 2 Core mold resin 21 Bottom opening 3 Coil 4 Coil mold resin 41 Outer covering portion 42 Inner covering portion 43 Bottom opening 44 Notch

Claims (8)

A cylindrical coil;
a core having legs around which the coil is wound;
Equipped with
the leg portion is not in contact with the inner circumferential surface of the coil over the entire area, and a gap is provided between the leg portion and the inner circumferential surface of the coil over the entire area;
A reactor characterized by the above. A cylindrical coil;
a core having legs around which the coil is wound;
Equipped with
The core is
a core mold resin that covers at least a portion of the core;
A core holding portion that holds the core;
having
The coil is
a coil molding resin that covers at least a portion of the coil;
A coil holding portion that holds the coil;
having
the core holding portion and the coil holding portion each independently hold the core or the coil,
Only the lower surface of the leg portion is in contact with the inner peripheral surface of the coil, and a gap is provided between the portion other than the lower surface of the leg portion and the inner peripheral surface of the coil;
A reactor characterized by the above. a heat dissipation member having elasticity between a bottom surface of the coil and a surface on which the reactor is mounted,
a bottom surface of the coil is in contact with the heat dissipation member and is not in contact with the installation surface;
The reactor according to claim 2 . The core is
a core mold resin that covers at least a portion of the core;
A core holding portion that holds the core;
having
The coil is
a coil molding resin that covers at least a portion of the coil;
A coil holding portion that holds the coil;
having
the core holding portion and the coil holding portion each independently hold the core or the coil, and a gap is provided between the leg portion and an inner peripheral surface of the coil;
The reactor according to claim 1 . The leg portion is provided in plurality,
The core further includes a yoke portion that connects the legs,
the core mold resin has a yoke covering portion that covers the yoke portion,
a gap is provided between the yoke covering part and the coil;
The reactor according to any one of claims 2 to 4, characterized in that the bottom surface of the yoke portion is not covered with the core mold resin and is exposed;
The reactor according to claim 5 . The inner circumferential surface of the coil is covered with the coil molding resin,
a notch is provided on an inner peripheral surface of the coil covered with the coil molding resin;
The reactor according to any one of claims 2 to 6, The core is made up of a plurality of core members,
the plurality of core members are bonded together by an adhesive;
The reactor according to any one of claims 1 to 7,

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