JP6451081B2 - Coil device - Google Patents

Description

  The present invention relates to a coil device that can be suitably used as an inductor, for example.

  As a surface mount inductor, for example, a coil device shown in Patent Document 1 below is known. As shown in Patent Document 1, the lid core and the pot core are joined using an adhesive, and the outer peripheral portion of the lid core and the upper end of the outer leg portion of the pot core are generally bonded. In general, an air gap is provided between the upper end of the middle leg portion of the pot core and the lid core.

  However, in such a conventional coil device, it has been difficult to ensure a DC superimposition characteristic and a high inductance at the same time.

JP 2007-96181 A

  The present invention has been made in view of such a situation, and an object of the present invention is to provide a coil device capable of simultaneously ensuring DC superimposition characteristics and high inductance.

In order to achieve the above object, a coil device according to the present invention comprises:
A pot core having a middle leg part and an outer leg part surrounding the middle leg part with a concave gap of a predetermined interval;
A coil part accommodated in the concave gap;
A coil device having a lid core that covers an upper part of the concave gap in which the coil part is accommodated and an upper part of the middle leg part,
A first magnetic body-containing resin is interposed between the upper end of the middle leg portion and the lid core.

  In the coil device according to the present invention, since the first magnetic body-containing resin is interposed between the upper end of the middle leg portion and the lid core, the magnetic body in the resin functions as part of the pot core to improve inductance. To do. In addition, the resin functions as a gap to improve magnetic saturation and improve DC superposition characteristics.

  Preferably, an air gap is formed between the outer leg portion and the lid core. With this configuration, the magnetic saturation is further improved, and the direct current superimposition characteristics are improved.

  Preferably, a second magnetic body-containing resin is interposed between the inner wall surface of the concave gap and the coil portion. By comprising in this way, the magnetic body in resin functions as a part of pot core, and an inductance further improves.

  Preferably, a positioning portion is formed between the center portion of the lid core and the upper end of the middle leg portion. The lid core and the middle leg portion are positioned by the positioning portion, and the characteristic variation can be improved.

  Preferably, the lead wire of the wire constituting the coil portion is drawn out to the outside of the outer leg portion near the upper end of the coil portion, and a groove for drawing out the lead wire to the outside is formed at the upper end of the outer leg portion. Is formed. By comprising in this way, 2nd magnetic body containing resin can be filled to the maximum height to the clearance gap between the inner wall face of a concave gap, and a coil part. In addition, by filling the concave gap with the second magnetic body-containing resin to the extent that the resin is not discharged to the outside through the groove, the coil portion is only accommodated in the concave gap, and the inner wall surface of the concave gap and the coil portion The gap between them can be filled with the second magnetic substance-containing resin to the maximum height.

  Preferably, a gap is formed between the upper end of the coil portion and the inner surface of the lid core. If no gap is provided, the stress due to the magnetic substance-containing resin concentrates on the lid core and the coil portion, but if there is a gap, the stress is relaxed.

  Preferably, the first magnetic body-containing resin is arranged at a higher position than the second magnetic body-containing resin. By comprising in this way, it becomes easy to form a gap between the upper end of a coil part and the inner surface of a cover core.

FIG. 1 is an overall perspective view of a coil device according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of the coil device shown in FIG. 3A is a schematic cross-sectional view taken along line III-III shown in FIG. FIG. 3B is a schematic cross-sectional view of a coil device according to another embodiment of the present invention. 4A is a schematic sectional view of a coil device according to another embodiment of the present invention, and FIG. 4B is a schematic sectional view of a coil device according to still another 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 2 according to the present embodiment is used as an inductor, for example, and includes a pot core 10, a lid core 30, and terminals 40 a and 40 b.

  As shown in FIGS. 2 and 3A, the pot core 10 has a cylindrical middle leg portion 12 protruding from the center portion of the core bottom wall 11 to the upper portion in the Z-axis direction, and a concave shape with a predetermined interval between the middle leg portion 12. And an outer leg portion 14 surrounded by a gap 18. In this embodiment, the concave gap 18 is formed in a thick cylindrical shape, the upper part in the Z-axis direction is open, and the coil part 20 can be inserted into the concave gap 18 from there. .

  In the present embodiment, the coil portion 20 is formed by winding a conductive wire 22 in a coil shape in advance so that a pair of lead wires 22a and 22b is drawn out in the upper part in the Z-axis direction. The inner diameter is equal to or larger than the outer diameter, and the outer diameter is equal to or smaller than the inner diameter of the inner peripheral surface of the outer leg portion 14.

  Note that the lead wires 22 a and 22 b constitute both ends of the wire 22. The wire 22 may be composed of a single wire or a stranded wire, and is preferably composed of an insulation-coated conductive wire.

  The inner peripheral surface of the outer leg portion 14 is a cylindrical outer peripheral surface, and the outer peripheral surface is a prismatic outer peripheral surface. In the present embodiment, the outer peripheral surface of the outer leg portion 14 has two corners adjacent to a square column. It has a shape in which a chamfered outer peripheral surface 14b is formed in the part, and has an outer peripheral surface shape of a hexagonal column as a whole. The upper surface 14a of the outer leg portion 14 in the Z-axis direction is positioned higher than the upper surface 12a of the middle leg portion 12 in the Z-axis direction in the Z-axis direction. In the drawing, the Z-axis is a direction that coincides with the axis of the middle leg portion 12 of the pot core 10 and also coincides with the winding axis of the coil portion 20.

  As shown in FIG. 1, the pair of terminals 40 a and 40 b have flat terminal bodies 41 a and 41 b that are in close contact with the outer peripheral surface 14 c of the outer leg portion 14 along the Z-axis direction. Lower locking pieces 42a and 42b are formed integrally with the main bodies 41a and 41b at the lower ends in the Z-axis direction of the terminal main bodies 41a and 41b, respectively, so as to be in close contact with the lower surface of the core bottom wall 11. Each of the lower locking pieces 42a and 42b is set to a length on the lower surface of the core bottom wall 11 so as not to contact and short-circuit each other.

  The upper locking pieces 43a and 43b are respectively integrated with the main bodies 41a and 41b so that the upper locking pieces 43a and 43b are in close contact with the upper end 14a of the outer leg portion 14 and / or the outer surface 34 of the lid core 34, respectively. Is formed. Each of the upper locking pieces 43a and 43b is set to have a length so as not to contact and short-circuit each other on the outer surface of the lid core 30.

  In the middle of the terminal bodies 41a and 41b in the Z-axis direction, connecting pieces 44a and 44b projecting toward the chamfered outer peripheral surface 14b are formed integrally with the main bodies 41a and 41b, respectively. Installation pieces 46a and 46b that are substantially perpendicular to the Z-axis are formed on the upper ends of the connection pieces 44a and 44b. The upper surfaces of the installation pieces 46a and 46b are designed so as to be substantially flush with the groove bottom surfaces of the notched grooves 16a and 16b formed on the upper portions of the respective chamfered outer peripheral surfaces 14b.

  Lead wires 22a and 22b projecting outward from the notched grooves 16a and 16b are installed on the upper surfaces of the installation pieces 46a and 46b, and the holding pieces 47a and 47b formed integrally with the installation pieces 46a and 46b. Lead wires 22a and 22b are sandwiched between and electrically connected to each other. The leading ends of the lead wires 22a and 22b are laser welded or soldered to the installation pieces 46a and 46b and the holding pieces 47a and 47b, respectively.

  As shown in FIG. 3A, the ring-shaped bottom surface 18 a of the concave gap 18 is also the top surface of the core bottom wall 11, but is flat so that the bottom surface of the coil portion 20 can be easily bonded via the second magnetic substance-containing resin 52. It is a surface. The height H3 from the bottom surface 18a to the notched grooves 16a and 16b is preferably high enough to accommodate the coil portion 20.

  In FIG. 3A, the height H1 is the height from the bottom surface 18a to the upper surface 12a of the middle leg portion 12, and is preferably smaller than the height H0 of the outer leg portion 14, and the height H1 is subtracted from the height H0. It is preferable that the dimension is substantially equal to the thickness of the lid core 30 in the Z-axis direction, and the outer surface 34 of the lid core 30 and the upper end 14a of the outer leg portion 14 are preferably substantially flush with each other.

  The first magnetic body-containing resin 50 is interposed between the inner surface 32 of the lid core 30 and the upper end of the middle leg portion 12 to ensure the joining thereof.

  It is preferable that the outer peripheral surface 36 of the lid core 30 has a circumferential surface shape in accordance with the shape of the inner peripheral surface of the outer leg portion 14, and as shown in FIGS. 1 and 3A, Although it may be in close contact with the peripheral surface, a predetermined air gap G2 may be provided as shown in FIG. 3b.

  In FIG. 3A, the height H2 is the height from the bottom surface 18a to the upper end of the coil part 20, and considering that the thickness of the second magnetic body-containing resin 52 is small, the Z-axis direction of the coil part 20 itself Is almost the same as the height of In the present embodiment, since the lead wires 22a and 22b are formed near the upper end of the coil portion 20, the height H3 is substantially the same as or slightly smaller than the height H2, but the lead wires 22a and 22b are replaced with the coil portion. When formed in the middle of 20 Z-axis directions, the height H3 can be made smaller than the height H2.

  The second magnetic body-containing resin 52 is filled between the outer surface of the coil portion 20 and the inner wall surface of the concave gap 18.

  The first magnetic body-containing resin 50 and the second magnetic body-containing resin 52 may be made of the same material or different materials, but they have the same basic composition and are magnetic in the resin. Contains body powder. The magnetic powder may be the same as or different from the magnetic material constituting the pot core 10 or the lid core 30. For example, a metal magnetic material containing Fe, Ni, Co, or the like can be used.

  The content of the magnetic powder contained in each of the first magnetic body-containing resin 50 and the second magnetic body-containing resin 52 is preferably the same, but may be different within a predetermined range. For example, the content of the magnetic powder contained in each of the first magnetic body-containing resin 50 and the second magnetic body-containing resin 52 is preferably 80 to 90% by weight with respect to the whole.

  The pot core 10 and the lid core 30 are preferably made of the same magnetic material, but may be made of different magnetic materials. The pot core 10 and the lid core 30 are each made of a magnetic material containing, for example, Fe, Mn—Zn, Ni—Zn, or the like. Moreover, these cores 10 and 30 are obtained by, for example, sintering magnetic substance powder into a predetermined shape after compression molding. Or these cores 10 and 30 can also be shape | molded using CIM shaping | molding (ceramic injection molding), MIM shaping | molding (metal injection molding), etc. FIG.

  The resin contained in the first magnetic body-containing resin 50 and the second magnetic body-containing resin 52 is preferably exemplified by resins such as epoxy and silicon.

  Before the second magnetic body-containing resin 52 before curing, the coil portion 20 shown in FIG. 2 is pre-filled into the bottom surface 18a of the concave gap 18 by a predetermined amount before being inserted into the concave gap 18, and then the coil The part 20 may be inserted into the concave gap 18. Pre-curing resin 52 is pre-filled so that it moves over the gap between the outer surface of coil portion 20 and the inner wall surface of concave gap 18 and stops before overflowing from notched grooves 16a and 16b. It is preferable to adjust the resin to be prepared.

  The first magnetic body-containing resin 50 before curing may be applied in advance to the inner surface 32 of the lid core 30 or the upper end 12a of the middle leg portion 12, and then these may be bonded together. The curing treatment of the first magnetic body-containing resin 50 and the second magnetic body-containing resin 52 can be performed by applying heat if the resin is a thermosetting resin, and is performed simultaneously after assembling as shown in FIG. 3A. It is preferable. However, the curing process may be performed separately.

  As shown in FIG. 3A, after finishing the curing process of the first magnetic body-containing resin 50 and the second magnetic body-containing resin 52, the terminals 40a and 40b shown in FIG. good. Further, the leading ends of the lead wires 22a and 22b, the installation pieces 46a and 46b, and the holding pieces 47a and 47b are joined after the terminals 40a and 40b are attached.

  In the coil device 2 according to this embodiment, since the first magnetic body-containing resin 50 is interposed between the upper end 12a of the middle leg portion 12 and the inner surface of the lid core 30, the magnetic body in the resin is the pot core 10 ( Alternatively, it functions as a part of the lid core 30) and the inductance is improved. In addition, the resin contained in the first magnetic body-containing resin 50 functions as a gap to improve magnetic saturation and improve the DC superimposition characteristics.

  Furthermore, in this embodiment, as shown in FIG. 3B, by forming an air gap G2 between the inner peripheral surface of the outer leg portion 14 and the outer peripheral surface 36 of the lid core 30, the magnetic saturation is further improved and the direct current is improved. Superimposition characteristics are improved.

  Further, in the present embodiment, there is a gap between the inner wall surface of the concave gap 18 (including the inner circumferential surface of the outer leg portion 14, the outer circumferential surface of the middle leg portion 12 and the bottom surface 18a) and the outer surface of the coil portion 20. Two magnetic substance-containing resin 52 is interposed. With this configuration, the magnetic body in the resin 52 functions as a part of the pot core 10 and the inductance is further improved.

  In the embodiment shown in FIGS. 1 to 3B, the inductance is improved as compared with the conventional coil device in which an air gap is provided between the upper end of the middle leg portion and the lid core as shown in Japanese Patent Application Laid-Open No. 2007-96181. In addition, the DC superposition characteristics are also improved.

  Furthermore, in the present embodiment, the lead wires 22a and 22b of the wire 22 constituting the coil portion 20 are drawn to the outside of the outer leg portion 14 near the upper end of the coil portion 20, and the upper end 14a of the outer leg portion 14 is Grooves 16a and 16b are formed to lead out the lead wires 22a and 22b. By comprising in this way, the 2nd magnetic body containing resin 52 can be filled to the maximum height in the clearance gap between the inner wall face of the concave clearance 18, and the outer surface of the coil part 20. FIG. Also, the grooves 16a. By filling the concave gap 18 with the second magnetic body-containing resin 52 to the extent that it is not discharged to the outside through 16b, the inner wall surface of the concave gap 18 and the coil can only be accommodated in the concave gap 18. The second magnetic body-containing resin 52 can be filled up to the maximum height in the gap between the portions 20.

  Further, in the present embodiment, an air gap G <b> 1 is formed between the upper end of the coil portion 20 and the inner surface 32 of the lid core 30. If the air gap G1 is not provided, the stress due to the magnetic substance-containing resin 50 or 52 is concentrated on the lid core 30 and the coil part 20, but if the air gap G1 is present, the stress is relaxed. Further, since the first magnetic body-containing resin 50 is arranged at a position higher in the Z-axis direction than the second magnetic body-containing resin 52, a gap is formed between the upper end of the coil portion 20 and the inner surface 32 of the lid core 30. It becomes easy to form.

  The present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the present invention.

  For example, as shown in FIGS. 4A and 4B, the coil devices 2a and 2b may be configured.

  In the coil device 2a shown in FIG. 4A, a positioning recess 38 is formed on the inner surface 32 of the lid core 30a located between the center portion of the lid core 30a and the upper end 12a of the middle leg portion 12. . The front end 12a of the middle leg portion 12 enters and fits into the recess 38, and these are positioned and joined by the first magnetic body-containing resin 50. Also in this embodiment, the first magnetic resin 50 is interposed between the recess 38 formed on the inner surface 32 of the lid core 30a and the upper end 12a of the middle leg portion 12.

  According to such a configuration, the center of the lid core 30a and the axis of the middle leg portion 12 are well aligned, and it becomes easy to form the air gap G2 shown in FIG. 3B uniformly in the circumferential direction. Variations in characteristics such as characteristics can be improved.

  Also, in the coil device 2b shown in FIG. 4B, an alignment convex portion 38b is formed on the inner surface 32 of the lid core 30b located between the center portion of the lid core 30b and the upper end 12a of the middle leg portion 12. In addition, a positioning recess 38 a is formed at the upper end of the middle leg 12. The convex portions 38b are inserted and fitted into the concave portions 38a, and these are positioned and joined by the first magnetic body-containing resin 50. Also in this embodiment, the first magnetic resin 50 is interposed between the inner surface 32 of the lid core 30b and the upper end 12a of the middle leg portion 12.

  According to such a configuration, the center of the lid core 30b and the axis of the middle leg portion 12 are well aligned, and the air gap G2 shown in FIG. 3B can be easily formed uniformly in the circumferential direction. Variations in characteristics such as characteristics can be improved.

2, 2a, 2b ... Coil device 10 ... Pot core 11 ... Core bottom wall 12 ... Middle leg portion 12a ... Upper end 14 ... Outer leg portion 14a ... Upper end 16a, 16b ... Drawer groove 18 ... Concave gap 18a ... Bottom surface 20 ... Coil portion 22 ... wire 22a, 22b ... lead wire 30, 30a, 30b ... lid core 32 ... inner surface 34 ... outer surface 36 ... outer peripheral surface 38, 38a ... positioning recess 38b ... positioning projection 40a, 40b ... terminal 41a, 41b ... terminal body 42a, 42b ... Lower locking pieces 43a, 43b ... Upper locking pieces 44a, 44b ... Connection pieces 46a, 46b ... Installation pieces 47a, 47b ... Holding pieces 50 ... First magnetic body-containing resin 52 ... Second magnetic body-containing resin

Claims (3)

A pot core having a middle leg part and an outer leg part surrounding the middle leg part with a concave gap of a predetermined interval;
A coil part accommodated in the concave gap;
A coil device having a lid core that covers an upper part of the concave gap in which the coil part is accommodated and an upper part of the middle leg part,
The lid core is provided inside the outer leg,
A first magnetic substance-containing resin is interposed between the upper end of the middle leg and the lid core,
Ri Thea gap is formed between the outer surface of the cover core and the inner peripheral surface of the outer leg,
The lead wire of the wire constituting the coil part is drawn out of the outer leg part near the upper end of the coil part, and a groove for drawing out the lead wire is formed in the upper end of the outer leg part. And
Between the inner wall surface of the concave gap and the coil portion, the second magnetic body-containing resin is filled to the height of the bottom surface of the groove,
Coil system air gap that is formed between the upper end and the inner surface of the lid core of the coil portion. The coil device according to claim 1 , wherein the first magnetic body-containing resin is disposed at a position higher than the second magnetic body-containing resin. The coil device according to claim 1 or 2 , wherein a positioning portion is formed at least one of a center portion of the lid core and an upper end of the middle leg portion.

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