JP2017103357A - Coil device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coil device capable of preventing occurrence of a crack due to an impact.SOLUTION: A coil device includes: a coil part formed by wounding an insulation coated wire in a hollow cylindrical state; a magnetic material including part that includes a magnetic material and a binding material connecting the magnetic material, and covers the coil part; a resin layer that is arranged in a coil inner part region surrounded by the coil part, has a coil inner resin part formed so as to surround a peripheral part of an axis of the coil part, and has a resin content higher than the magnetic material including part. At least one end part of the resin layer in an axial direction of the coil part is positioned in the coil inner part region.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a coil device used as an inductor element or the like.

  In various electronic and electrical devices, many coil devices are mounted as inductor elements. For example, as an example of such a coil device, one in which a coil portion is covered with a green compact obtained by mixing a binder containing a thermosetting resin and magnetic powder is known (see Patent Document 1). .

JP 2002-203731 A

  However, in the conventional coil device, there is a problem that a crack occurs in the magnetic material containing portion including the magnetic material at the time of impact at the time of dropping or thermal shock, and in particular, at the position where the axis of the coil portion intersects the outer peripheral surface of the coil device. There is a problem that cracks due to impact occur in a portion where such a magnetic material-containing portion continues through the inside of the coil portion.

  Further, in the conventional coil device, the insulating coating formed on the surface of the wire constituting the coil portion is damaged by the magnetic material contained in the magnetic material-containing portion due to the pressure applied at the time of molding, and the insulating property of the wire surface There is a problem that cannot be maintained. As a technique for avoiding such a problem, it is conceivable to limit the pressure during molding to a low level. However, when such a limitation is performed, the density of the magnetic material-containing portion cannot be sufficiently increased, and the magnetic material There arises a problem that it is difficult to increase the permeability of the containing portion.

  The present invention has been made in view of such a situation, and an object thereof is to provide a coil device that can prevent generation of cracks due to impact.

In order to achieve the above object, a coil device according to the present invention comprises a coil portion formed by winding an insulation-coated wire into a hollow cylindrical shape,
Containing a magnetic material and a binding material for connecting the magnetic material, and a magnetic material containing portion covering the coil portion;
A resin layer that is disposed in a coil inner region surrounded by the coil portion and is formed so as to surround the axis of the coil portion; and a resin layer having a resin content higher than that of the magnetic material-containing portion; , And
At least one end of the resin layer in the axial direction of the coil portion is located in the coil inner region.

  The resin layer having the resin portion in the coil acts as a buffer portion when an impact is applied to the coil device, and can prevent a problem that a crack caused by the impact occurs in the magnetic material containing portion. In particular, the resin part in the coil is formed so as to surround the axis of the coil part in the coil inner region, and the resin part in the coil is relatively cracked around the position where the axis of the coil part intersects the outer peripheral surface of the coil device. Even at the position where it is likely to occur, the problem of cracking in the magnetic material containing portion can be effectively prevented. Even if it has a resin layer, if the resin layer wraps the entire coil part and is formed so as to separate the magnetic body containing part from the coil part, the impact on the magnetic material containing part is absorbed. May not work sufficiently. However, in the resin layer according to the present invention, at least one end portion is located in the coil inner region and does not have a shape surrounding the outer periphery of the coil portion, so that the impact transmitted to the magnetic material containing portion can be effectively mitigated. In addition, when pressure is applied to the coil part during coil molding, the resin layer is deformed to absorb the pressure applied from the magnetic material containing part to the coil part and damage the insulation coating of the wire. Can be prevented. Therefore, it becomes possible to raise the pressure at the time of shaping | molding from the conventional coil apparatus, and to improve the magnetic permeability of a magnetic material containing part.

  Further, for example, the resin part in the coil may have an inclined part in which a distance from the inner peripheral side surface of the coil part changes along the axial direction, and the coil part extends along the axial direction. You may have a parallel part which is parallel with respect to an inner peripheral side surface.

  The in-coil resin portion having the inclined portion and the parallel portion has a width in the axial direction in the coil inner region, and therefore has a more three-dimensional shape together with the shape surrounding the axis. Therefore, the coil device having such a resin portion in the coil can more effectively prevent the problem that the magnetic material containing portion is cracked.

  In addition, for example, the resin layer may include an outside-coil resin portion that is disposed in a coil external region that is outside the coil portion and is connected to the other end of the in-coil resin portion.

  The outside-coil resin portion disposed in the coil outer region can also absorb an impact in the same manner as the in-coil resin portion, and has an effect of preventing a problem that a crack occurs in the magnetic material containing portion.

  Further, for example, the resin layer may include a gap adjusting portion sandwiched between the magnetic material-containing portions with respect to the flow direction of the magnetic flux generated in the magnetic material-containing portion according to the current flowing through the insulation-coated wire. .

  The coil device having the gap adjusting unit can change the thickness and shape of the gap adjusting unit in the resin layer, so that the magnetic saturation characteristics and DC superimposition characteristics of the coil device can be obtained without changing the outer shape or the inner diameter of the coil unit. Can be easily controlled.

  Further, for example, the resin layer may be continuous up to the outer surface of the magnetic material containing part.

  In the coil device having such a resin layer, a crack is generated in the magnetic material containing portion by impact by continuing the resin layer to a place where the crack is likely to occur, such as near the outer surface of the magnetic material containing portion. The problem can be effectively prevented. Moreover, the resin layer can be made to act suitably as a magnetic gap by continuing the resin layer to the outer surface.

  For example, the magnetic material-containing portion may include a resin as the binding material, and the resin as the binding material may be the same resin as the resin included in the resin layer.

  The resin contained in the magnetic material-containing part as the binder and the resin contained in the resin layer are not particularly limited, but from the viewpoint of increasing the binding properties by approximating the material of the magnetic material-containing part and the resin layer, From the viewpoint of increasing the thermal shock resistance by approximating the shrinkage characteristics to the magnetic material-containing portion, the resin as the binder is preferably the same resin as that contained in the resin layer.

FIG. 1 is a perspective view of a coil device according to a first embodiment of the present invention. 2 is a cross-sectional perspective view of the coil device shown in FIG. FIG. 3 is a partially transparent perspective view of the coil device shown in FIG. 4 is a conceptual diagram showing a manufacturing process of the coil device shown in FIG. FIG. 5 is a cross-sectional view of a coil device according to a second embodiment of the present invention. FIG. 6 is a cross-sectional view of a coil device according to a third embodiment of the present invention. FIG. 7 is a cross-sectional view of a coil device according to a fourth embodiment of the present invention. FIG. 8 is a sectional view of a coil device according to a fifth embodiment of the present invention.

  Hereinafter, the present invention will be described based on embodiments shown in the drawings.

  As shown in FIG. 1, the coil device 10 according to the first embodiment includes a magnetic material containing portion 30 that covers the coil portion 20 (see FIG. 3), and a resin layer 40 that has a higher resin content than the resin magnetic material containing portion 30. And have. The coil device 10 is used as a circuit element (inductor element) mounted on, for example, a personal computer or a portable electronic device, but the application of the coil device 10 and the device on which the coil device 10 is mounted are not particularly limited.

  As shown in FIG. 3, which is a partial perspective view of FIG. 1, the coil part 20 is accommodated inside the magnetic material containing part 30. The coil part 20 is formed by winding an insulating coated wire 20a in a hollow cylindrical shape. The insulation-coated wire 20a has a conducting wire for passing a current and an insulation coating for covering the conducting wire. The insulation-coated wire 20a employed in the coil unit 20 is a flat wire whose rectangular cross section is rectangular with respect to the current direction, and has a higher DC density and higher DC resistance than the conductor having a circular cross section. There is an advantage that can be reduced. However, the insulating coated wire 20a employed by the coil unit 20 is not limited to this, and may have a circular cross section.

  Both end portions 20aa of the insulation covered wire 20a are exposed on the outer surface 31 of the magnetic material containing portion 30, and a terminal portion (not shown) connected to the end portion 20aa is formed on the outer surface 31. As shown in FIG. 1, the conductive wire is exposed from the insulating coating at the end 20aa of the insulating coated wire 20a, and electrical connection with the terminal portion formed on the outer surface 31 is ensured. The terminal portion is formed by forming a metal film on the outer surface 31 of the magnetic material-containing portion 30 by plating or joining a metal plate material. It is not limited. A method for joining the insulating coated wire 20a and the terminal portion includes welding and adhesion using a conductive adhesive, but is not particularly limited.

  As shown in FIG. 3, the surface 21 of the hollow cylindrical coil portion 20 includes an inner peripheral side surface 21a facing the axis B of the coil portion 20, an outer peripheral side surface 21b facing the outer peripheral direction of the coil portion 20, and an inner peripheral side surface 21a. The outer peripheral side surface 21b is perpendicular to the upper surface 21c and the bottom surface 21d. In the description of the embodiment, the side close to the mounting surface when the coil device 10 is mounted on a substrate or the like is the bottom surface 21d, and the surface facing the bottom surface 21d is the top surface 21c.

  As shown in FIG. 2, the part other than the coil unit 20 in the coil device 10 can be divided into a coil inner region 12 surrounded by the coil unit 20 and a coil outer region 14 outside the coil unit 20. The coil internal region 12 is a region from the axis B of the coil unit 20 to the inner peripheral side surface 21a of the coil unit 20 with respect to the direction orthogonal to the axis B of the coil unit 20, and with respect to the direction along the axis B of the coil unit 20. This is a region sandwiched between two extended surfaces of the upper surface 21c and the bottom surface 21d of the coil portion 20. On the other hand, the coil external region 14 includes the upper surface 21c of the coil portion 20 and a portion above the extended surface, the bottom surface 21d of the coil portion 20 and a portion below the extended surface, and the outer peripheral side surface 21b of the coil portion 20. It consists of the outer part.

  The conducting wire of the insulation coated wire 20a is made of, for example, Cu, Al, Fe, Ag, Au, phosphor bronze or the like. The insulating coating layer is made of, for example, polyurethane, polyamideimide, polyimide, polyester, polyester-imide, polyester-nylon, or the like.

  As shown in FIG. 2 showing a cross section of the coil device 10, the magnetic material containing portion 30 defines a substantially outer shape of the coil device 10 and has a substantially rectangular outer shape. The magnetic material-containing portion 30 contains a magnetic material and a binding material that connects the magnetic materials. As will be described later, the magnetic material powder 30 is compression-molded or injection-molded into granules containing the magnetic material powder and the binding material. It is formed. Although it does not specifically limit as a magnetic material contained in the magnetic material containing part 30, Ferrite, such as Mn-Zn and Ni-Cu-Zn, Sendust (Fe-Si-Al; Iron-silicon-aluminum), Fe-Si- Examples include Cr (iron-silicon-chromium), permalloy (Fe-Ni), permalloy (PB, PC), carbonyl iron, carbonyl Ni, amorphous powder, and nanocrystal powder. Although it does not specifically limit as a binding material, For example, resin, such as an epoxy resin, a phenol resin, an acrylic resin, a polyester resin, a polyimide, a polyamideimide, a silicon resin, and those combining these are illustrated.

  The magnetic material containing unit 30 functions as a core in the coil device 10. The magnetic material containing part 30 has a shaft part 32, an upper part 33, a bottom part 34, and an outer peripheral part 35. The shaft portion 32 is a portion disposed inside the coil portion 20, and is surrounded by the inner peripheral side surface 21 a of the coil portion 20. The upper part 33 is located above the coil part 20 and contacts the upper surface 21 c of the coil part 20. The bottom part 34 is located below the coil part 20, and is disposed in a state in which the outside-coil resin part 42 of the resin layer 40 described later is sandwiched between the bottom part 21 d of the coil part 20. The outer peripheral portion 35 is disposed on the outer periphery of the coil portion 20 and is in contact with the outer peripheral side surface 21 b of the coil portion 20.

  Of the portions constituting the magnetic material containing portion 30, the shaft portion 32 is disposed in the coil inner region 12, and the other upper portion 33, bottom portion 34, and outer peripheral portion 35 are disposed in the coil outer region 14. In the magnetic material containing part 30, the flow of magnetic flux in the direction indicated by the arrow A in FIG. 2 or in the opposite direction is applied to the shaft part 32, the upper part 33, the bottom part 34 and the outer peripheral part 35 in accordance with the current flowing through the insulating coated wire 20a. Arise.

  As shown in FIG. 2, the coil device 10 includes a resin layer 40 having a resin content higher than that of the magnetic material containing unit 30. The resin layer 40 is disposed in the coil inner region 12 and is formed so as to surround the axis B of the coil portion 20, and the coil disposed in the coil outer region 14 and connected to the coil inner resin portion 41. And an outer resin portion 42.

  In this embodiment, the resin part 41 in a coil is comprised by the inclination part from which the space | interval with respect to the internal peripheral side surface 21a of the coil part 20 changes along the axis B direction. The resin part 41 in the coil has a ring shape that circulates around the axis B. More specifically, the resin part 41 in the coil is arranged in the coil inner region 12 and has a frustum (the central axis substantially coincides with the axis B ( The shape is similar to the side shape of a truncated cone, a truncated cone, or the like.

  The coil outer resin portion 42 is a portion sandwiched between the bottom surface 21 d of the coil portion 20 and the bottom portion 34 of the magnetic material containing portion 30, and a portion sandwiched between the bottom portion 34 and the outer peripheral portion 35 of the magnetic material containing portion 30. It consists of.

  As shown in FIGS. 2 and 3, the in-coil resin portion 41 and the non-coil resin portion 42 are continuous with each other to form one resin layer 40. When the coil device 10 is viewed from a direction orthogonal to the axis B, as shown in FIG. 2, the upper end portion 40 b that is one end portion in the resin layer 40 in the direction of the axis B of the coil portion 20 is the coil inner region 12. Located in. In contrast, the lower end portion 40 c of the resin layer 40 is located in the coil outer region 14.

  When viewed from the direction of the axis B, the outer peripheral shape of the resin layer 40 is rectangular, and a through hole is formed at the center. The outer peripheral edge of the resin layer 40 coincides with the outer peripheral edge of the magnetic material containing part 30, and the resin layer 40 continues to the outer surface 31 of the magnetic material containing part 30.

  In FIG. 2, the resin layer 40 includes an in-coil resin portion 41 that is an inclined portion and a non-coil resin portion 42 that is sandwiched between the bottom portion 34 and the outer peripheral portion 35 of the magnetic material containing portion 30. With respect to the flow direction of the magnetic flux indicated by A, both sides are sandwiched by the magnetic material containing part 30 and function as a gap adjusting part. By changing the thickness and shape of these portions in the resin layer 40 (for example, the size of the central through-hole of the resin layer 40), without changing the outer shape of the coil device 10, the inner diameter of the coil portion 20, etc. The magnetic saturation characteristic and the DC superposition characteristic of the coil device 10 can be easily controlled.

  In the magnetic material containing portion 30, the outer peripheral portion 35 and the bottom portion 34 are connected via the resin layer 40, whereas the shaft portion 32 and the upper portion 33 and the upper portion 33 and the outer peripheral portion 35 are connected to the resin layer 40. It is connected directly without going through.

  Although the thickness of the resin layer 40 is not specifically limited, For example, it is preferable to set it as 0.1-3 micrometers, and it is more preferable to set it as 0.1-1 micrometer. The resin content of the resin layer 40 is not particularly limited as long as it is higher than that of the magnetic material containing part 30, but is preferably 20% or more by weight, and more preferably 40% or more.

  Although resin contained in the resin layer 40 is not specifically limited, It is preferable that it is the same resin as resin contained in the magnetic material containing part 30 as a binder. Examples of the resin contained in the resin layer 40 include resins such as epoxy resins, phenol resins, acrylic resins, polyester resins, polyimides, polyamideimides, silicon resins, heat resistant rubbers, and combinations thereof. . Moreover, the resin layer 40 may be comprised only with resin similar to resin contained in the magnetic material containing part 30 as a binder.

  Although the size of the coil apparatus 10 of this embodiment is not specifically limited, For example, width is 10-20 mm, depth is 10-20 mm, and height is 1-10 mm.

An example of the manufacturing method of the coil apparatus 10 shown in FIGS. 1-3 is demonstrated using FIG.
In the manufacture of the coil device 10, first, a lower material 134 (see FIG. 4A) that is a material of the entire bottom 34 of the magnetic material containing portion 30 and a part of the shaft portion 32 of the coil device 10 is prepared. The lower material 134 includes a rectangular parallelepiped portion and a frustum-shaped projection portion formed on one surface of the rectangular parallelepiped portion. The lower material 134 is formed by compression molding a granule containing a magnetic powder and a binder.

  Next, as illustrated in FIG. 4A, a resin layer material 140 that is a material of the resin layer 40 is formed on one surface of the lower material 134. The resin layer material 140 is formed by spray-coating a resin solution containing a resin constituting the resin layer 40 on the surface of the lower material 134 on which the frustum-shaped protrusions are formed. At this time, of the surface of the lower material 134 on which the frustum-shaped protrusions are formed, the central portion (the upper bottom portion of the frustum) where the resin layer material 140 is not formed is covered with a mask before spray coating.

  Next, as shown in FIG. 4B, the coil part 20 prepared in the state of an air-core coil is installed on the resin layer material 140 formed on the surface of the lower material 134. Further, the lower material 134, the resin layer material 140, and the coil part 20 prepared as shown in FIG. 4B are placed in the mold, and from there, the granules containing the magnetic material powder and the binder are made of gold. Put in the mold and pressurize. Thereby, on the lower material 134, the resin layer material 140, and the coil part 20 shown in FIG. 4B, the other part of the shaft part 32 in the magnetic material containing part 30, the material of the upper part 33 and the outer peripheral part 35, and The upper material 135 is molded to obtain the coil device material 100 as shown in FIG.

  The coil device material 100 shown in FIG. 4C is subjected to heat treatment for removing volatile components contained in the resin layer material 140 and curing the resin as the binder contained in the magnetic material containing portion 30. Furthermore, the terminal part which conduct | electrically_connects to edge part 20aa (refer FIG. 1) is formed in the surface of the heat-treated coil apparatus material 100 by barrel plating, etc., and the coil apparatus 10 is obtained. Before forming the terminal portion, the end portion 20aa and the terminal portion are electrically connected to a part of the outer surface 31 of the magnetic material containing portion 30 shown in FIG. 1 by sputtering plating or conductive paste. A formation may be formed.

  In the coil device 10 shown in FIG. 2 and the like, the resin layer 40 acts as a buffer when an impact or thermal shock due to a collision is applied to the coil device 10, and a crack due to the impact occurs in the magnetic material containing portion 30. You can prevent problems. In particular, the resin layer 40 has an in-coil resin portion 41 formed so as to surround the axis B of the coil portion, and the upper end portion 40b of the resin layer 40 is located in the coil inner region 12. For this reason, it is possible to effectively prevent a problem that a crack is generated in the magnetic material containing portion due to an impact. Further, since the in-coil resin portion 41 and the non-coil resin portion 42 in the resin layer 40 are continuous, it becomes possible to effectively absorb the impact by the entire resin layer 40, and the magnetic material containing portion 30 can be absorbed by the impact. Can prevent the problem of damage.

  In addition, the outer resin portion 42 of the coil 40 of the resin layer 40 continues to the outer surface 31 of the magnetic material containing portion 30, so that the outer peripheral portion 35 located on the outer peripheral side of the coil portion 20 in the magnetic material containing portion 30. As described above, the occurrence of cracks due to impact can be effectively prevented even in a portion where the thickness is small and cracks are relatively likely to occur.

  Further, the resin layer 40 is deformed when pressure is applied during molding, thereby serving as a cushion that absorbs pressure applied to the coil part 20, and insulation of the insulating covered wire 20 a constituting the coil part 20. The problem that the coating is damaged can be prevented. Therefore, in manufacture of such a coil apparatus 10, it becomes possible to raise the pressure at the time of shaping | molding from the conventional coil apparatus, and in the coil apparatus 10 shape | molded by the pressure higher than before, the magnetic permeability of the magnetic material containing part 30 is possible. The coil device 10 having a high L value can be realized.

  Although the shape of the resin layer 40 is not particularly limited, in the coil device 10 illustrated in FIG. 2, the in-coil resin portion 41 includes an inclined portion that is inclined with respect to the inner peripheral side surface 21 a of the coil portion 20 along the axis B direction. It has become. In such a coil device 10, since the resin layer 40 has a more three-dimensional shape combined with the shape surrounding the axis B, it effectively acts as an impact absorbing portion that absorbs an impact, and the magnetic material containing portion The problem of cracks occurring in 30 can be more effectively prevented. In addition, from the viewpoint of preventing a problem that a crack is generated in the central portion (around the axis B) of the coil device 10, the in-coil resin portion 41 is parallel to the inner peripheral side surface 21a of the coil portion 20 (see FIG. 5). It is preferable to incline along the direction of the axis B rather than being.

  In addition, the coil device 10 changes the thickness and shape of the resin layer 40 functioning as a gap adjusting portion, so that the magnetic saturation characteristics and the coil device 10 can be obtained without changing the outer shape, the inner diameter of the coil portion 20, and the like. The direct current superimposition characteristic can be easily controlled.

  The shape of the coil device 10 shown in FIGS. 1 to 3 and the manufacture of the coil device 10 shown in FIG. 4 are only one embodiment of the coil device according to the present invention, and the technical scope of the present invention is limited to this. It is not something.

  FIG. 5 is a cross-sectional view of the coil device 200 according to the second embodiment. The coil device 200 is the same as the coil device 10 according to the first embodiment except that the shape of the resin layer 240 is different.

  The resin layer 240 of the coil device 200 includes an in-coil resin portion 241 disposed in the coil inner region 212 that is inside the coil portion 20 and an outer coil portion that is disposed in the coil outer region 214 that is outside the coil portion 20. And a resin portion 242.

  The in-coil resin portion 241 is formed along the inner peripheral side surface 21 a of the coil portion 20, and is a parallel portion that is parallel to the inner peripheral side surface 21 a of the coil portion 20 along the axis B direction of the coil portion 20. It is configured. The in-coil resin portion 241 has a ring-like shape that circulates around the axis B. More specifically, the in-coil resin portion 241 is an elliptical cylinder that is disposed in the coil inner region 212 and whose center axis substantially coincides with the axis B. It has a shape that approximates the side shape.

  The outside-coil resin portion 242 is configured by a portion sandwiched between the bottom surface 21 d of the coil portion 20 and the bottom portion 234 of the magnetic material containing portion 230. In the coil device 200, similarly to the coil device 10, the in-coil resin portion 241 and the out-coil resin portion 242 are continuous with each other to form one resin layer 240. When the coil device 200 is viewed from a direction orthogonal to the axis B, the upper end portion 240b, which is one end portion of the resin layer 240 in the axis B direction of the coil portion 20, is substantially the same as the extended surface of the upper surface 21c of the coil portion 20. They coincide and are located in the coil inner region 212.

  When viewed from the direction of the axis B, the outer peripheral shape of the resin layer 240 is rectangular, and a through hole is formed in the center. However, the outer peripheral edge of the resin layer 40 is smaller than the outer peripheral edge of the magnetic material containing part 230, and the resin layer 240 does not reach the outer surface 231 of the magnetic material containing part 230.

  In the manufacturing method of the coil device 200 shown in FIG. 5, the protrusion formed on one surface of the lower material 134 has a cylindrical shape, and the shape of the mask formed on the lower material 134 when the resin layer material 140 is formed. 4 is the same as the manufacturing method of the coil device 10 shown in FIG.

  As with the coil device 10 according to the first embodiment, when the impact or thermal shock due to the collision is applied to the coil device 200, the coil device 200 acts as a buffer portion, and cracks due to the impact are generated. Can be prevented from occurring in the magnetic material containing portion 230. In addition, since both the in-coil resin portion 241 and the out-coil resin portion 242 are in close contact with the coil portion 20, it preferably serves as a cushion for absorbing pressure applied to the coil portion 20, and the magnetic material containing portion 230. Can be effectively prevented from damaging the insulating coating of the insulating coating wire 20a constituting the coil portion 20.

  FIG. 6 is a cross-sectional view of a coil device 300 according to the third embodiment. The coil device 300 is the same as the coil device 10 according to the first embodiment except that the shape of the resin layer 340 is different.

  The resin layer 340 of the coil device 300 is configured only by the in-coil resin portion disposed in the coil internal region 312 that is the inside of the coil unit 20.

  The resin layer 340 which is a resin part in the coil is formed along the inner peripheral side surface 21a of the coil part 20, and is parallel to the inner peripheral side surface 21a of the coil part 20 along the axis B direction of the coil part 20. It has the parallel part 340a and the upper bottom part 340b which connects the parallel part 340a along the direction orthogonal to the axis B direction. The resin layer 340 has a cap-shaped outer shape that is formed so as to surround the axis B of the coil portion 20. More specifically, the resin layer 340 has a coil inner portion so that the central axis substantially coincides with the axis B. It is arranged in the region 312 and has a shape approximating a hollow elliptical cylinder having only one bottom (upper bottom).

  When the coil device 300 is viewed from a direction orthogonal to the axis B, the upper bottom portion 340 b constitutes one end of the resin layer 340 in the axis B direction of the coil portion 20 and is located in the coil inner region 312. .

  When viewed from the direction of the axis B, the outer peripheral shape of the resin layer 340 is substantially oval, and unlike the resin layer 40 and the resin layer 240, no through hole is formed. The upper bottom part 340b is sandwiched on both sides of the magnetic material containing part 330 with respect to the flow direction of the magnetic flux formed in the magnetic material containing part 330, and functions as a gap adjusting part.

  In the manufacturing method of the coil device 300 shown in FIG. 6, the protrusion formed on one surface of the lower material 134 has a cylindrical shape, and the shape of the mask formed on the lower material 134 when the resin layer material 140 is formed. 4 is the same as the manufacturing method of the coil device 10 shown in FIG.

  Similar to the coil devices 10 and 200 according to the first and second embodiments, in the coil device 300, the resin layer 340 acts as a buffer when a shock or thermal shock due to a collision is applied to the coil device 300. The problem that cracks due to impact occur in the magnetic material containing portion 330 can be prevented. In addition, the resin layer 340 suitably serves as a cushion that absorbs pressure applied to the coil part 20, and when the magnetic material containing part 30 is molded, the insulating coating of the insulating coating wire 20 a that constitutes the coil part 20 is formed. The problem of damage can be effectively prevented.

  In addition, the coil device 300 can easily control the magnetic saturation characteristics and the direct current superposition characteristics of the coil device 10 by changing the thickness of the upper bottom portion 340b.

  FIG. 7 is a cross-sectional view of a coil device 400 according to the fourth embodiment. The coil device 400 is the same as the coil device 10 according to the first embodiment, except that the resin layer 440 includes only a portion corresponding to the in-coil resin portion 41 in the resin layer 40 shown in FIG.

  The manufacturing method of the coil device 400 shown in FIG. 7 is the same as the manufacturing method of the coil device 10 shown in FIG. 4 except that the shape of the mask formed on the lower material 134 when forming the resin layer material 140 is different. is there.

  Similarly to the coil device 10 according to the first embodiment, when the impact or thermal shock due to the collision is applied to the coil device 400, the coil device 400 acts as a buffer portion, and cracks due to the impact occur. Can be prevented from occurring in the magnetic material containing part 430. In addition, the coil device 400 can easily control the magnetic saturation characteristics and the direct current superposition characteristics of the coil device 400 by changing the thickness and shape of the resin layer 440.

  FIG. 8 is a cross-sectional view of a coil device 500 according to the fifth embodiment. The coil device 500 is the same as the coil device 10 according to the first embodiment except that the shape of the in-coil resin portion 541 in the resin layer 540 is different from the in-coil resin portion 41 in the resin layer 40 shown in FIG. is there.

  As shown in FIG. 8, the in-coil resin portion 541 in the resin layer 540 has an inclined portion 541 a whose interval with the inner peripheral side surface 21 a of the coil portion 20 changes along the axis B direction, and a direction orthogonal to the axis B direction. And an upper bottom portion 541b connecting the inclined portion 541a. The in-coil resin portion 541 has a cap-like shape whose opening expands downward. More specifically, the in-coil resin portion 541 is disposed in the coil inner region 12 and the central axis substantially coincides with the axis B. It has a shape that approximates a hollow truncated cone having only a bottom.

  The coil device 500 can be manufactured by a method similar to the method shown in FIG. 3, but can also be manufactured by the manufacturing method shown below. That is, in the manufacturing method of the coil device 500, first, granules containing a magnetic material powder and a resin as a binder are put into a mold, and a lower part having a frustum-shaped protrusion as shown in FIG. Press mold the material. The shape of the lower material to be pressure-molded corresponds to the lower part 530a of the magnetic material containing part 530 in the coil device 500 shown in FIG. Further, when molding the lower material, a resin release film is mounted on the surface of the mold that contacts the frustum-shaped protrusion. As a result, the resin contained in the granules as a binder concentrates on the surface of the molded lower material that has been in contact with the release film, and a resin layer material that becomes the resin layer 540 is formed.

  Next, the coil part 20 is mounted on the lower material on which the resin layer material is formed. Further, an upper material prepared separately by molding a granule including a magnetic material and a binder into the shape of the upper portion 530b is combined with the lower material with the coil portion 20 interposed therebetween. Then, after heat-processing like the coil apparatus 10, a terminal part is formed and the coil apparatus 500 is obtained.

  The coil device 500 has the same effect as the coil device 10 according to the first embodiment.

  Hereinafter, although this invention is demonstrated based on a more detailed Example, this invention is not limited to these Examples.

(Sample preparation)
As shown in FIG. 4, after molding the bottom material 134 with granules containing a magnetic substance and a binder, a resin layer material 140 is formed on the surface by spray coating (FIG. 4A). The coil part 20 is installed in the mold and put into the mold (FIG. 4B). Furthermore, the granule containing a magnetic body and a binder was put into a mold and pressure-molded to obtain a coil device material 100, and then the coil device material was heat-treated to obtain a coil device 10. It should be noted that the process of forming the resin layer material 140 was omitted when the sample 1 and the sample 2 as comparative examples were created. The sample conditions are as follows.
・ Granule: (Fe-Si-Cr alloy (average particle size 0.5 to 10 μm) as a magnetic material is added to a silane coupling agent dissolved in water and heated at 110 ° C. for 30 minutes to insulate the magnetic material surface. After coating the magnetic material with 3% by weight of an epoxy resin diluted in acetone with respect to the weight of the magnetic powder and stirring, the mesh was passed through a 250 micron mesh and dried at room temperature for 24 hours. Obtained.)
Coil part: An air-core coil (10T, inner diameter 1.3 mm) prepared using an insulation-coated wire (wire: AIW (cross-section 0.06 × 0.3 mm), insulation coating: polyamideimide) was used.
-Resin layer material: Epoxy resin diluted in acetone was used.
Molding pressure: 2t to 6t (see Table 1)
・ Heating conditions: 170 ° C., 1.5 hours ・ Coil device dimensions: 2.0 × 1.6 × 0.7 mm (2016 size)
Resin layer thickness: 0 μm, 0.1 μm, 1.0 μm, 3.0 μm

(test)
No. obtained as described above. 1-No. With respect to the sample No. 6, an impact test, an effective μi measurement, a film damage test, and a DC superposition characteristic were measured. The results are shown in Table 1. The conditions for each test are as follows.
Impact test: 1000 cycles of temperature change from low temperature (-55 ° C) to high temperature (+ 125 ° C) to confirm whether the change in the characteristic value (inductance value) of each sample before and after the test is within the allowable range. A level where the change in inductance value is within 10% is judged as a good product.
DC superposition characteristics: frequency 1.000 kHz, applied voltage 0.5 V, temperature 23 ° C., DC current 0 to 5 A (1 kHz inductance)
Effective μi: Measures effective initial permeability when DC is superimposed (described above).
Film damage test: Confirmed by measuring the characteristic value (inductance value) of each sample that there was no short circuit in the coil due to damage to the insulation film. When the change in inductance value at 1000 kHz is within 10% and the inductance value is measured by changing the frequency, the level at which a predetermined resonance peak is observed is judged as a non-defective product.

(Evaluation)
Sample No. having a resin layer 3-No. No. 6 shows an improvement in the impact test, and sample No. 6 having no resin layer. 1 confirmed that the impact resistance was improved. When there was no resin layer, it was found that the coating pressure was damaged at the molding pressure of 4 t / cm ² (sample No. 2), and it was difficult to increase the molding pressure further. (Sample No. 2 to Sample No. 6), no film damage occurred even at a molding pressure of 6 t / cm ² , and it was confirmed that the molding pressure could be increased as compared with the case where there was no resin layer. Sample No. having a resin layer 3, Sample No. 4, it was confirmed that the effective μi can be improved by increasing the molding pressure. Furthermore, the material No. which changed the thickness of the resin layer between 0.1-3.0 micrometers. 4 to Sample No. From the comparison of 6, it was confirmed that the DC superposition characteristics of the coil device can be changed by the thickness of the resin layer.

DESCRIPTION OF SYMBOLS 10, 200, 300, 400, 500 ... Coil apparatus 20 ... Coil part 20a ... Insulation coated wire 20aa ... End part 21a ... Inner peripheral side surface 21d ... Bottom surface 30, 230, 330, 430, 530 ... Magnetic material containing part 31,231 ... outer surface 33 ... upper part 34, 234, 334 ... bottom part 35, 235, 335 ... outer peripheral part 40, 240, 340, 440, 540 ... resin layer 41, 241, 541 ... resin part 541a in coil ... inclined part 42, 242 ... resin outside coil

Claims (7)

A coil portion formed by winding an insulation-coated wire into a hollow cylindrical shape;
Containing a magnetic material and a binding material for connecting the magnetic material, and a magnetic material containing portion covering the coil portion;
A resin layer that is disposed in a coil inner region surrounded by the coil portion and is formed so as to surround the axis of the coil portion; and a resin layer having a resin content higher than that of the magnetic material-containing portion; , And
At least one end portion of the resin layer in the axial direction of the coil portion is located in the coil inner region.   2. The coil device according to claim 1, wherein the in-coil resin portion includes an inclined portion in which an interval with respect to an inner peripheral side surface of the coil portion changes along the axial direction.   2. The coil device according to claim 1, wherein the resin portion in the coil includes a parallel portion that is parallel to the inner peripheral side surface of the coil portion along the axial direction.   4. The resin layer according to claim 1, wherein the resin layer includes a resin part outside the coil that is disposed in a coil external region that is outside the coil part and is connected to the resin part within the coil. Coil device.   The said resin layer has a gap adjustment part by which both sides are pinched | interposed into the said magnetic material containing part regarding the flow direction of the magnetic flux which arises in the said magnetic material containing part according to the electric current which flows into the said insulation coating wire. The coil device according to claim 4.   The coil device according to any one of claims 1 to 5, wherein the resin layer is continuous to an outer surface of the magnetic material-containing portion.   The resin as the binder is contained in the magnetic material-containing portion, and the resin as the binder is the same resin as that contained in the resin layer. The coil device according to any one of 6 to 6.

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