JP2017098382A - Coil device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coil device having an electrode part with excellent wettability to a solder.SOLUTION: The coil device includes: a magnetic core having an axial part and a magnetic core end part connected to the axial part; a coil part formed by winding a wire to the axial part; and an electrode part that is provided to the magnetic core end part, and is formed by a good conductor. The electrode part includes: a fixing surface that is provided to a side surface not crossing to a center axis of the coil part in the magnetic core end part, and in which a wire end part of the wire is fixed; and an outer side surface that is the side surface of the magnetic core end part, and is provided to a position away from the fixing surface to the axial part. The outer side surface includes: a first part in which a distance to the center axis is short from the fixed-end to which a tip of the wire end part in the fixing surface is fixed; and a second part of which the distance to the center axis is short from the first part.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a coil device used as a pulse transformer or the like, and more particularly to a coil device suitably used for surface mounting.

  Various types of electronic and electrical devices are equipped with many coil devices as inductor elements and transformers. In order to cope with the downsizing of electronic devices in recent years, in addition to downsizing of the coil device itself, such a coil device has good uniformity with less manufacturing variation that enables high-density mounting, and surface mounting. Is required. Issues that require improvement from this point of view include, for example, an alloy layer (formed on the core of the wire and the terminal) that deteriorates the wettability with respect to solder when fixing the wire to the terminal in the manufacturing process of the coil device. In other words, the surface mountability of the coil device is deteriorated.

  As a conventional technique corresponding to such a problem, there has been proposed a technique in which a step surface lower than a fixed surface is formed on a terminal to provide a surface on which an alloy layer is difficult to be formed (see Patent Document 1).

JP 2013-191694 A

  However, in the conventional coil device, when an excess portion of the wire to be cut off from the coil device at the time of manufacture contacts and reacts with the electrode portion, an alloy layer that deteriorates wettability with respect to solder spreads on the terminal surface, and the electrode portion There is a problem that wettability may decrease.

  This invention is made | formed in view of such an actual condition, and provides the coil apparatus which has an electrode part with favorable wettability with respect to solder | pewter.

In order to achieve the above object, a coil device according to the present invention includes a magnetic core having a shaft portion and a magnetic core end portion connected to the shaft portion;
A coil portion formed by winding a wire around the shaft portion;
An electrode portion provided at the end of the magnetic core and made of a good conductor;
The electrode portion is provided on a side surface that does not intersect the central axis of the coil portion at the magnetic core end portion, and is a fixed surface to which a wire end portion of the wire is fixed, and the side surface of the magnetic core end portion, and the shaft portion And an outer surface provided at a position farther from the fixed surface,
The outer surface includes a first portion that is closer to the central axis than a fixed end to which the tip of the wire end on the fixed surface is fixed, and a second portion that is closer to the central axis than the first portion. It is characterized by having.

  In the coil device according to the present invention, since the first portion and the second portion of the electrode portion are located closer to the central axis than the fixed end, the wire end not only in the direction along the central axis but also in the direction orthogonal to the central axis. It is separated from the part. Therefore, the phenomenon that the alloy layer formed by the reaction between the core material of the wire and the surface of the electrode portion spreads to the outer surface is prevented, and the electrode portion has good wettability with respect to solder. Further, since the second part is located closer to the central axis than the first part, the second part is further away from the wire end than the first part. Therefore, in the coil device having the second portion, it is possible to prevent a problem that an excess portion of the wire adheres to the outer surface during the wire cutting process and an alloy layer is formed, and the electrode portion is good against solder. Has good wettability. Furthermore, since the surface area of the outer surface is increased by having the first portion and the second portion, it is possible to ensure a wide region on the outer surface where no alloy layer is formed and which exhibits good wettability with respect to solder. Is possible.

  Further, by using the electrode portion having the first portion and the second portion, it is possible to secure a large volume of the magnetic core body including the magnetic core end portion as compared with the case where the entire outer surface is simply brought close to the central axis. Therefore, such a coil device is advantageous for downsizing. Furthermore, by using such an electrode part having the first part and the second part, the wire can be easily cut at a predetermined position on the fixed surface in the manufacturing process of the coil device. Further, even when the cutting position of the wire is deviated, it is possible to prevent the end of the wire from continuing to the end face of the coil device, and to prevent the problem that the dimensional accuracy varies.

  Further, for example, the center position of only the second portion may be provided at a position closer to the shaft portion than the center position of the entire outer surface.

  In the coil device having such an outer surface, an alloy layer is particularly difficult to be formed on a portion of the first portion that is located farther from the shaft portion than the second portion. Good wettability. Further, when the first part is mounted with the fixed surface side as the mounting surface, the distance between the first part and the land of the mounting board is short. Therefore, the coil device having such a first part has a land between the land of the mounting board and the electrode part. In the meantime, it is possible to form a good solder fillet.

Further, for example, the coil device according to the present invention may have at least two electrode parts including a first electrode part and a second electrode part,
The magnetic core has a pair of magnetic core end portions respectively connected to both end portions of the shaft portion,
One of the magnetic core end portions may be provided with the first electrode portion having a first fixing surface which is the fixing surface to which the one wire end portion of the wire is fixed,
The other end of the magnetic core may be provided with the second electrode portion having a second fixing surface, which is the fixing surface to which the other end of the wire is fixed,
The side surface of the magnetic core end portion provided with the first fixed surface and the side surface of the magnetic core end portion provided with the second fixed surface may be located on the same plane.

  Since such a coil device can use the fixed surface side of an electrode part as a mounting surface, it is advantageous with respect to size reduction of an electrode part and the whole coil apparatus including this. Moreover, since the outer surface on the mounting surface side has good wettability with respect to solder as described above, such a coil device can be suitably used for surface mounting.

  Further, for example, the fixing surface may be inclined in a direction away from the central axis with respect to a direction from the shaft portion toward the magnetic core end portion.

  In the coil device having the fixed surface inclined as described above, the problem that the shape of the wire end and the cutting position of the wire vary and the problem that the alloy layer is formed in a wide range of the electrode part can be prevented. The electrode part has good wettability with respect to solder.

  Further, for example, the wire end portion may have an inclined tip end portion whose thickness in the direction perpendicular to the central axis becomes thinner toward the tip end.

  In the coil device having the inclined tip portion, it is possible to prevent the problem that the material of the wire to be originally cut is attached to the terminal surface by being pulled by the wire end portion when the wire is cut. Therefore, such a coil device is suitably controlled so that the alloy layer that deteriorates the wettability with respect to the solder does not spread on the terminal surface, and in addition to the small variation in the shape of the wire end, The wettability with respect to the solder can also be suitably secured.

  The electrode part may be a metal terminal fitting.

  Since the coil device in which the electrode part is a metal terminal fitting is easy to manufacture and the durability of the electrode part is also good, such a coil device has good and uniform quality.

Further, for example, the metal terminal fitting may have an inner surface that contacts the side surface of the magnetic core end,
The fixed surface may be inclined with respect to the inner surface.

  The coil device in which the electrode part is a metal terminal fitting having such an inner surface has a good workability in the wire cutting process because the fixing surface of the electrode part is favorably supported by the side surface of the end of the magnetic core. With high productivity and stable quality.

FIG. 1 is a perspective view of a coil device according to a first embodiment of the present invention. FIG. 2 is a perspective view showing a main body magnetic core of the coil device shown in FIG. FIG. 3 is a sectional view of the coil device shown in FIG. FIG. 4 is an enlarged cross-sectional view in which the periphery of the electrode portion in the coil device shown in FIG. 1 is enlarged and a plan view of the electrode portion. FIG. 5 is a conceptual diagram showing a wire end forming process. FIG. 6 is a schematic enlarged view in which the periphery of the cutting position of the wire material in the wire end forming step is enlarged. FIG. 7 is an enlarged cross-sectional view in which the periphery of the electrode portion in the coil device according to the first modification is enlarged and a plan view of the electrode portion. FIG. 8 is a plan view showing electrode portions according to second and third modifications. FIG. 9 is an enlarged cross-sectional view in which the periphery of the electrode portion in the coil device according to the fourth modification is enlarged and displayed.

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

  FIG. 1 is a schematic perspective view of a coil device 10 according to an embodiment of the present invention. The coil device 10 includes a main body core 20 as a magnetic core, a coil part 30, and a first electrode part 41 and a second electrode part 51 as electrode parts. In addition, the coil device 10 includes a flat core 16 that forms a magnetic path together with the main body core 20. The coil device 10 described in the embodiment is a pulse transformer suitable for surface mounting. However, the coil device according to the present invention is not limited to this, and may be an inductor element, a voltage conversion transformer, or the like. Absent. In the drawing of the coil device 10, for convenience of explanation, the lower portion facing the mounting substrate side in the mounted state is displayed so as to face upward, and is displayed in reverse from the mounting posture.

  FIG. 2 is a perspective view showing the main body core 20 of the coil device 10. The main body core 20 includes a shaft portion 21 and a first end portion 22 and a second end portion 26 as a pair of magnetic core end portions connected to the shaft portion 21. The first end portion 22 and the second end portion 26 are respectively connected to both end portions of the shaft portion 21, and the main body core 20 constitutes a drum core.

  The first end portion 22 has a lower side surface 24 facing the mounting surface side, an upper side surface 25 opposite to the lower side surface 24, a surface connected to the shaft portion 21, and a surface opposite to the surface connected to the shaft portion 21. And an end face 23 which is a side face, and has a substantially rectangular parallelepiped outer shape. The lower side surface 24 and the upper side surface 25 are surfaces that do not intersect the central axis A of the coil portion 30, and the end surface 23 is a surface that intersects the central axis A. On the lower surface 24, a convex surface 24a and a concave surface 24b having a step are formed. The lower side surface 24 is a surface on which a first fixing surface 42 of the first electrode portion 41 described later is provided. In more detail, the first fixing surface 42 extends in a direction away from the central axis A in the lower side surface 24. It is provided on the protruding convex surface 24a (see FIGS. 1 and 3). The concave surface 24b is recessed to the central axis A side from the convex surface 24a, and the distance to the upper side surface 25 which is the opposite surface is shorter than the convex surface 24a.

  As shown in FIG. 2, the second end portion 26 has a substantially rectangular parallelepiped outer shape symmetric with respect to the first end portion 22, and similarly to the first end portion 22, the second end portion 26 faces downward on the mounting surface side. It has a side surface 28, an upper surface 29 that is the surface opposite to the lower surface 28, an end surface 27, and the like. The lower side surface 28 and the upper side surface 29 are surfaces that do not intersect the central axis A of the coil portion 30, and the end surface 27 is a surface that intersects the central axis A. The lower surface 28 of the second end portion 26 is a surface on which the second fixing surface 52 of the second electrode portion 51 is provided. More specifically, the second fixing surface 52 is formed on the convex surface 28 a of the lower surface 28. Provided. The concave surface 28b is recessed toward the central axis A from the convex surface 28a, and the distance to the upper side surface 29 which is the opposite surface is closer to the convex surface 28a.

  The upper surface 25 of the first end 22 and the upper surface 29 of the second end 26 are both flat surfaces and are located on the same surface. As shown in FIG. 1, the flat plate core 16 having a rectangular parallelepiped shape is fixed to the upper side surface 25 of the first end portion 22 and the upper side surface 29 of the second end portion 26. A closed magnetic circuit is formed that loops with 20. Depending on the application of the coil device 10, a gap may be provided between the flat plate core 16 and the main body core 20, and the coil device 10 may be in a mode in which the flat plate core 16 is not used.

  The main body core 20 and the flat core 16 are made of Ni-Zn ferrite, Mn-Zn ferrite, or a sintered or molded body of a magnetic material containing a metal magnetic body. The main body core 20 and the flat core 16 can be bonded using, for example, an adhesive. When the coil device 10 is surface-mounted, the outer surface of the flat core (the surface opposite to the surface to which the main body core 20 is joined) is sucked by the suction arm of the mounting device, so that the coil device 10 is transported to the mounting position. Is done.

  As shown in FIG. 1, the coil portion 30 is formed by winding wires 31, 32, 33, and 34 around a shaft portion 21 (see FIG. 3) of the main body core 20. Although the coil part 30 of the coil apparatus 10 is comprised by the four wires 31, 32, 33, 34, the number of the wires contained in the coil part 30 is not specifically limited. The first wire ends 31 a, 32 a, 33 a, and 34 a, which are one wire ends of the wires 31, 32, 33, and 34, are connected to the first end of the body core 20 from the portion wound around the shaft portion 21. It is drawn out to the part 22 side and is fixed to the first electrode part 41. The second wire ends 31b, 32b, 33b, and 34b, which are the other wire ends of the wires 31, 32, 33, and 34, are connected to the first portion of the body core 20 from the portion wound around the shaft portion 21. It is pulled out toward the two end portions 26 and is fixed to the second electrode portion 51.

  The wires 31, 32, 33, and 34 are made of, for example, coated conductors and have a structure in which a core material made of a good conductor is covered with an insulating coating film. Although the wire diameter of the wires 31-34 is not specifically limited, Preferably it is 0.02-0.1 mm. The wires 31 to 34 are wound around the shaft portion 21 in a four-layer structure, and the central axis A of the coil portion 30 configured by the wires 31 to 34 is the central axis of the shaft portion 21 of the main body core 20. It almost agrees. The number of layers in which the wires 31 to 34 are wound may be appropriately changed according to the required characteristics of the coil device 10 and the like, and the wires 31 to 34 are densely attached to the shaft portion 21 as shown in FIG. It may be wound, or may be wound partially with a gap.

  As shown in FIG. 1, the coil device 10 includes a first electrode portion 41 provided at the first end portion 22 of the main body core 20 and a second electrode portion 51 provided at the second end portion 26 of the main body core 20. Including at least two electrode portions. The coil device 10 includes three first electrode portions 41 and three second electrode portions 51, a total of six electrode portions. The number of electrode portions included in the coil device 10 is the same as that of the coil device 10. It is changed as appropriate according to the function, application, number of wires, and the like.

  The first electrode portion 41 has a first fixing surface 42 to which at least one of the wire first end portions 31a, 32a, 33a, 34a, which is one wire end portion of the wires 31, 32, 33, 34, is fixed. doing. As shown in FIG. 1, the wire first end portions 31a and 32a are fixed to the first fixing surface 42 of the common first electrode portion 41, and the wire first end portions 33a and 34a have one first end. One wire first end portion 33 a and 34 a is fixed to the first fixing surface 42 of the electrode portion 41. In the coil device 10, since the three first electrode portions 41 have the same shape, the first electrode portion 41 to which the wire first end portion 32a (and the wire first end portion 31a) is fixed will be described. Description of the first electrode portion 41 will be omitted. The first electrode portion 41 may have a different shape such as a terminal width depending on the number of wire first end portions 31a to 34a to be fixed.

  The first fixing surface 42 to which the wire first end portions 31a and 32a are fixed is provided on the convex surface 24a of the lower surface 24 of the first end portion 22 shown in FIG. FIG. 3 is a cross-sectional view of the coil device 10 by a cross section perpendicular to the upper side surfaces 25 and 29 of the first end portion 22 and the second end portion 26 and passing through the first electrode portion 41 and the second electrode portion 51. . However, in FIG. 3, the coil part 30 and the flat core 16 excluding the wire end parts 32a and 32b are not shown.

  As shown in FIG. 3, the convex surface 24 a and the concave surface 24 b of the lower side surface 24 on which the first fixing surface 42 is provided are surfaces extending in a direction parallel to the central axis A. However, while the convex surface 24 a and the concave surface 24 b are surfaces extending in a direction parallel to the central axis A, the first fixed surface 42 is in the central axis A with respect to the direction B from the shaft portion 21 toward the first end portion 22. It is not parallel but inclined.

  FIG. 4 is an enlarged cross-sectional view in which the periphery of the first electrode part 41 in FIG. 3 is enlarged. The first fixed surface 42 shown in FIG. 4 is inclined in a direction away from the central axis A with respect to the direction B from the shaft portion 21 toward the first end portion 22. The inclination angle α of the first fixed surface 42 is not particularly limited as long as it is larger than 0 degree and smaller than 90 degrees, but is preferably 3 to 20 degrees from the viewpoint of improving the uniformity of the shape of the wire first end portion 32a. .

  As shown in FIG. 4A, the wire first end portion 32a fixed to the first fixing surface 42 has an inclined tip portion 32aa in which the thickness in the direction perpendicular to the central axis A decreases toward the tip. It is preferable. The effect of the inclined tip portion 32aa will be described later together with the fixing method of the wire 32.

  The first electrode portion 41 has an outer surface 44 which is the lower surface 24 of the first end portion 22 and is provided at a position farther from the first fixed surface 42 with respect to the shaft portion 21. The outer side surface 44 is provided on the concave surface 28b of the outer side surface 44 of the first end 22 with a slight gap between the outer side surface 44 and the concave surface 28b.

  The outer side surface 44 has a first portion 44a closer to the central axis A and the upper side surface 25 than the fixed end 42a at which the tip of the wire first end portion 32a is fixed on the first fixed surface 42, and the first portion 44a. Furthermore, it has the 2nd part 44b with which the distance with respect to the central axis A and the upper surface 25 is near. Such an outer surface 44 is difficult to form an alloy layer in which the core material of the wire 32 and the plating layer of the first electrode portion 41 react when the wire 32 is fixed. Good properties.

  As shown in FIG. 4B, which is a plan view of the first electrode portion 41, the outer surface 44 has a second portion 44 b that is close to the central axis A and the upper surface 25 (see FIG. 4A). The first portion 44a surrounds the periphery. Accordingly, the first portion 44a has a region 44aa farther from the shaft portion 21 than the second portion 44b and a region 44ab closer to the shaft portion 21 than the second portion 44b. Further, the center position 44 bc of only the second portion 44 b is provided at a position closer to the shaft portion 21 than the center position 44 c of the entire outer surface 44.

  The first electrode part 41 is an L-shaped metal terminal fitting, and the extension part 46 of the first electrode part 41 is fixed to the end surface 23 of the first end part 22 with an adhesive or the like. The first electrode portion 41 made of a metal terminal is more durable than an electrode portion made of a printed layer, a plating layer, or the like formed on the core body, and in the wire end forming step described later. Has good workability because it is less likely to break.

  As shown in FIG. 1, the second electrode portion 51 has a second fixing surface 52 to which at least one of the wire second end portions 31b, 32b, 33b, 34b of the wires 31, 32, 33, 34 is fixed. doing. The wire second end portions 33b and 34b are fixed to the second fixing surface 52 of the common second electrode portion 51, and the second fixing of one second electrode portion 51 is performed for the wire second end portions 31b and 32b. One wire second end portion 31 b and 32 b is fixed to the surface 52. Since the three second electrode portions 51 have the same shape, the second electrode portion 51 to which the wire second end portion 32b is fixed will be described, and the description of the other second electrode portions 51 will be omitted. Further, in the description of the second electrode part 51, the description of the parts common to the first electrode part 41 is omitted.

  The second fixing surface 52 to which the wire second end portion 32b is fixed is provided on the convex surface 28a of the lower side surface 28 of the second end portion 26 shown in FIG. As shown in FIG. 3, the second fixed surface 52 is inclined in a direction away from the central axis A with respect to a direction C from the shaft portion 21 toward the second end portion 26. The inclination angle of the second fixed surface 52 is the same as the inclination angle α (see FIG. 4) of the first fixed surface 42. Further, the wire second end portion 32b fixed to the second fixing surface 52 is similar to the wire first end portion 32a fixed to the first fixing surface 42 in the direction perpendicular to the central axis A toward the tip. It is preferable to have an inclined tip portion where the thickness becomes thin.

  Further, the second electrode portion 51 is the lower surface 28 of the second end portion 26, similar to the first electrode portion 41, and is an outer surface provided at a position farther from the second fixed surface 52 with respect to the shaft portion 21. 54. The outer surface 54 includes a first portion 54a and a first portion 54a that are closer to the central axis A and the upper side surface 29 than the fixed end where the tip of the wire second end portion 32b is fixed on the second fixed surface 52. Further, the second portion 54b is closer to the central axis A and the upper side surface 29. The second electrode portion 51 is an L-shaped metal terminal fitting similar to the first electrode portion 41, and the extension portion 56 of the second electrode portion 51 is fixed to the end surface 27 of the second end portion 26 with an adhesive or the like. Has been.

  The first electrode part 41 and the second electrode part 51 can be formed, for example, by performing a bending process or surface plating such as Ni or Sn on a metal or alloy plate material. And the 2nd electrode part 51 will not be specifically limited if comprised with a good conductor.

  Hereinafter, an example of a method for manufacturing the coil device 10 will be described. In the manufacture of the coil device 10, first, the first electrode portion 41 and the second electrode portion 51 are fixed to the main body core 20 obtained by molding magnetic powder of a soft magnetic material. As shown in FIG. 3, the first electrode portion 41 and the second electrode portion 51 are fixed by bonding extension portions 46 and 56 to the end surfaces 23 and 27 of the first end portion 22 and the second end portion 26. The At this time, the adhesive is not applied to the lower side surfaces 24 and 28 of the first end portion 22 and the second end portion 26, and the convex surfaces 24 a and 28 a and the concave surfaces 24 b and 28 b, the first electrode portion 41 and the second electrode portion 51. And is not glued. Thereby, the following problems resulting from variations in the thickness of the cured adhesive layer formed by curing the adhesive can be solved. That is, the coil device 10 can prevent a problem that manufacturing variations occur in the distances from the lower side surfaces 24 and 28 to the fixing surfaces 42 and 52 and the outer surfaces 44 and 54 of the first and second electrode portions 41 and 51.

  Next, after winding the wire material which is the material of the 1st-4th wires 31-34 around the axial part 21 of the main body core 20, the both ends are each set to the 1st electrode part 41 and the 2nd electrode part 51, respectively. It fixes and cut | disconnects an excess part and forms wire end part 31a-34a, 31b-34b (refer FIG. 3). As a wire material that is a material of the first to fourth wires, for example, a core material made of a good conductor such as copper (Cu) is covered with an insulating material made of imide-modified polyurethane, and the outermost surface is a thin resin such as polyester. What was covered with the film | membrane can be used.

  FIG. 5 is a conceptual diagram illustrating a process of forming the wire first end portion 32a. The other wire first end portions 31a, 33a, and 34a are formed in the same manner as the wire first end portion 32a. As shown in FIG. 5A, the wire material 70, which is the material of the wire 32, is wound around the shaft portion 21 of the main body core 20, and then pulled out in the direction B from the shaft portion 21 toward the first end portion 22. It is. At this time, the wire material 70 is pulled out along the first fixed surface 42 of the first electrode portion 41, and a part of the wire material 70 comes into contact with the first fixed surface 42. The end portion of the wire material 70 is pulled in the direction B with a predetermined tensile force.

  Next, as shown in FIG. 5B, the heater chip 80 is brought close to the first fixed surface 42 of the first electrode portion 41, and the wire material 70 is sandwiched between the heater chip 80 and the first fixed surface 42. . Further, by pressing the heater chip 80 between the first fixed surfaces 42, a part of the wire material 70 is melted and joined to the first fixed surfaces 42. At this time, the core material (Cu) of the wire material and the plating film (Ni and Sn) on the terminal surface are alloyed, and an alloy layer is formed in the boundary region between the wire and the electrode portion, thereby obtaining a sufficient bonding force. It is done. Further, the movement of the heater chip 80 and the heating of the wire material 70 proceed, whereby the wire material 70 sandwiched between the heater chip 80 and the first fixing surface 42 is cut, and the wire first end portion 32a is formed. . After the cutting, the surplus portion 70a ahead of the wire first end portion 31a is detached in the extending direction of the first fixing surface 42 by the tensile force. Such a joining / cutting method is efficient because the joining and cutting can be performed in one step, and is particularly effective when the wires 31 to 34 are thin.

  FIG. 6 is an enlarged view for explaining a state at the time of cutting the wire material 70 by the heater chip 80. In the step of forming the wire first end portion 32a described above, the first electrode portion 41 is maintained while keeping the lower surface 80a of the heater chip 80 substantially parallel to the lower surface 24 of the first end portion 22, particularly the convex surface 24a. The first fixed surface 42 is approached. At this time, since the first fixed surface 42 is inclined with respect to the central axis A and the convex surface 24a, the space between the first fixed surface 42 and the lower surface 80a of the heater chip 80 has a wedge shape. Accordingly, the wire first end portion 32a formed by being sandwiched and fixed between the first fixing surface 42 and the lower surface 80a of the heater chip 80 has a thickness in the direction perpendicular to the central axis A toward the tip. An inclined tip portion 32aa is formed in which the thickness becomes thinner. Since the wire first end portion 32a has the inclined tip end portion 32aa, the shape of the wire first end portion 32a and the formation range of the alloy layer formed around the wire first end portion 32a can be made uniform.

  Further, the first fixed surface 42 is inclined with respect to the direction B in a direction away from the central axis A, that is, a direction approaching the lower surface 80 a of the heater chip 80. Therefore, the wire material 70 is cut with high precision in the vicinity of the end portion of the lower surface 80a far from the shaft portion 21, and the problem that the position of the fixed end 42a varies can be prevented. In addition, since the position of the fixed end 42a is accurately determined, the problem of the alloy layer spreading to the outer surface 44 having a step with respect to the first fixed surface 42 can be reliably prevented. Furthermore, as shown in FIG. 5 (b), immediately after the wire material 70 is cut, the surplus portion 70a ahead of the wire first end portion 32a is detached in the direction away from the central axis A. The problem of adhering to the outer side surface 44 can be prevented.

  Furthermore, since the second portion 44b of the outer surface 44 is located further on the central axis A side than the first portion 44a, the surplus portion 70a of the wire material 70 is more difficult to adhere than the first portion 44a, and the core of the wire material 70 The alloy layer formed by the reaction between the material and the surface of the first electrode portion 41 can be effectively prevented from spreading to the direction B side from the second portion 44b. Therefore, in the first portion 44a, the region 44aa farther from the shaft portion 21 than the second portion 44b has particularly good wettability with respect to solder.

  The coil device 10 having the outer surface 44 composed of the first portion 44a and the second portion 44b as described above has a concave surface 24b and a convex surface 24a, as compared with the case where the entire outer surface 44 is simply moved closer to the central axis A side. A level | step difference becomes small and the volume of the main body core 20 containing the 1st edge part 22 can be ensured large. For this reason, the coil apparatus 10 is advantageous with respect to size reduction. Further, since the distance between the mounting surface and the region 44aa of the first portion 44a having good wettability with respect to the solder is small, such a coil device 10 is provided between the land of the mounting substrate and the first electrode portion 41. It is possible to form a good solder fillet, and it can be suitably used as a coil device for surface mountability.

  As shown in FIG. 4B, the center position 44bc of only the second portion 44b is closer to the shaft portion 21 than the center position 44c of the entire outer surface 44, thereby being farther from the shaft portion 21 than the second portion 44b. The area 44aa of the first portion 44a having particularly suitable wettability with respect to solder can be appropriately ensured.

  As shown in FIG. 6, the first fixing surface 42 of the first electrode portion 41 is inclined with respect to the inner side surface 43 that contacts the convex surface 24 a of the lower side surface 24 at the first end portion 22, and the inner side surface 43 is preferably parallel to the convex surface 24a. Since the inner side surface 43 is parallel to the convex surface 24a, the first fixed surface 42 is stably supported by the convex surface 24a, the workability at the time of forming the wire first end portion 32a is improved, and the first electrode portion 41 is provided. This contributes to improvement of shape accuracy by preventing plastic deformation.

  The wire second end portions 31b to 34b shown in FIG. 1 are also formed in the same manner as the wire first end portion 32a described with reference to FIGS. Finally, the coil apparatus 10 is obtained by fixing the flat core 16 to the main body core 20 on which the first electrode part 41, the second electrode part 51, and the coil part 30 are formed.

  In the coil device 10 as described above, the outer surface 44 composed of the first portion 44a and the second portion 44b is attached to the electrode portions 41 and 51 of the surplus portion 70a of the wire material 70 and the alloy layer is excessive. By preventing the spread, the electrode portions 41 and 51 have good wettability with respect to solder. Therefore, the coil apparatus 10 has suitable mounting properties.

  In the coil device 10, the first and second fixing surfaces 42 and 52 to which the wire end portions 31 a to 34 a and 31 b to 34 b are fixed are connected from the shaft portion 21 to the first end portion 22 or the second end portion 26. It is inclined in a direction away from the central axis A with respect to the direction to go. Thereby, it is possible to prevent the occurrence of variations in the cutting position in the wire cutting step and the shapes of the wire end portions 31a to 34a, 31b to 34b, and the coil device 10 has a highly accurate outer shape with little manufacturing variation. Has stable quality.

  Moreover, if the cutting position in the wire cutting step varies, an alloy layer in which the core material of the wires 31 to 34 reacts with the plating layer of the first and second electrode portions 41 and 51 is excessively formed. There is a possibility that the wettability of the electrode portions 41 and 51 to the solder is deteriorated. However, since the coil device 10 can control the cutting position of the wire material 70 and the shapes of the wire end portions 31a to 34a and 31b to 34b with high accuracy, the alloy device is prevented from being excessively formed, and the first and first The wettability of the two electrode portions 41 and 51 to the solder can be kept good. Therefore, the coil device 10 has good mountability.

  Moreover, in the coil apparatus 10, the convex surface 24a of the lower surface 24 of the 1st end part 22 in which the 1st fixing surface 42 is provided, and the convex surface 28a of the lower surface 28 of the 2nd end part 26 in which the 2nd fixing surface 52 is provided. Are located on the same plane. For this reason, the coil apparatus 10 can use the side in which the 1st fixing surface 42 and the 2nd fixing surface 52 are provided as a mounting surface at the time of implementing to a board | substrate etc. The coil device 10 maintains good wettability of the first and second electrode portions 41 and 51 with respect to solder even when the mounting surface is the side on which the first fixing surface 42 and the second fixing surface 52 are provided. Good mountability.

  As mentioned above, although this invention was demonstrated using the coil apparatus 10 which concerns on embodiment, this invention is not limited to embodiment mentioned above, It has many other embodiment and modifications. Needless to say.

  FIG. 7A is an enlarged cross-sectional view showing the periphery of the first electrode unit 141 in the coil device according to the first modification, and FIG. 7B is a plan view of the first electrode unit 141. . The coil device according to the first modification is the same as the coil device 10 according to the first embodiment with respect to the coil portion 30 excluding the main body core 20, the flat core 16, and the wire end portion.

  The first electrode portion 141 shown in FIGS. 7A and 7B has a first fixing surface 142 to which the wire first end portion 132a is fixed and a shaft portion (not shown) of the main body core 20. The outer surface 144 is provided at a position far from the first fixed surface 142. The first fixed surface 142 of the first electrode portion 141 is substantially parallel to the central axis A.

  The outer side surface 144 has a first portion 144a closer to the central axis A and the upper side surface 25 (see FIG. 2) than the fixed end 142a at which the tip of the wire first end portion 32a is fixed on the first fixed surface 142; The second portion 144b is closer to the central axis A and the upper side surface 25 than the first portion 144a. As shown in FIG. 7 (b), the second portion 144b of the outer surface 144 is composed of two independent depressions, unlike the second portion 44b of the outer surface 44 shown in FIG. 4 (b).

  FIG. 8A is a plan view of the first electrode portion 241 according to the second modification. The outer surface 244 of the first electrode portion 241 shown in FIG. 8A has a first portion 244a and a first portion 244a closer to the central axis A and the upper side surface 25 (see FIG. 2) than the first fixing surface 242. Furthermore, it has the 2nd part 244b with which the distance with respect to the central axis A and the upper surface 25 is near. The second portion 244b of the outer side surface 244 is configured by four independent depressions having a substantially rectangular opening shape. The first electrode portion 241 is the same as the first electrode portion 41 shown in FIG. 4 and the like except for the shape of the outer surface 244.

  FIG. 8B is a plan view of the first electrode portion 341 according to the third modification. The outer surface 344 of the first electrode portion 341 shown in FIG. 8B has a first portion 344a and a first portion 344a that are closer to the central axis A and the upper surface 25 (see FIG. 2) than the first fixing surface 342. Furthermore, it has the 2nd part 344b with which the distance with respect to the central axis A and the upper surface 25 is near. The second portion 344b on the outer side surface 344 is composed of four independent depressions having a substantially circular opening shape. The first electrode portion 341 is the same as the first electrode portion 41 shown in FIG. 4 and the like except for the shape of the outer surface 344.

  As described above, the number and shape of the second portions 144b, 244b, and 344b formed on the outer surfaces 144, 244, and 344 of the first electrode portions 141, 241, and 341 are not particularly limited, and the first electrode according to the modification example is not limited. The portions 141, 241 and 341 also prevent the alloy layer from being excessively formed in the wire end forming step, and exhibit good wettability with respect to solder. In addition, the surface of the second portion 144b, 244b, 344b may be any surface as long as it is recessed toward the central axis A with respect to the first portions 144a, 244a, 344a. The surface of the second portion 144b, 244b, 344b may be configured by combining a plurality of planes, or may be configured by one or a plurality of curved surfaces.

  FIG. 9 is a cross-sectional view illustrating the first electrode portion 441 included in the coil device according to the fourth modification. The first electrode portion 441 shown in FIG. 9 is configured by a conductive metal paste layer such as Ag and a plating layer covering the paste layer on the first end 422 of the main body core. The first electrode portion 441 formed by paste and plating includes a first fixing surface 442 to which the wire first end portion 432a is fixed, and a first fixing surface 442 from the first fixing surface 442 to the central axis of the coil portion. It has an outer surface 444 provided at a farther position. A part 442a of the first fixed surface 442 is inclined with respect to the direction B in a direction away from the central axis.

  The outer side surface 444 includes a first portion 444a that is closer to the central axis A than the fixed end 442a at which the tip of the wire first end 432a is fixed on the first fixed surface 442, and a central axis A that is further than the first portion 444a. And a second portion 444b having a short distance to. Even when the first electrode portion 441 is composed of a paste layer and a plating layer, a fixed surface 442a inclined with respect to the central axis is formed by forming a step on the lower side surface 424 of the first end portion 422. The first and second portions 444a and 444b having different distances to the central axis A can be formed.

  As the first and second electrode parts other than the metal terminal fitting, in addition to the first electrode part 441 described above, an electrode part constituted only by a plating layer such as electrolytic plating, Ag, and an epoxy resin And those obtained by forming a plating layer on the surface of a resin electrode using the above mixture, and those obtained by superimposing a plating layer on a sputter layer such as Ni. Further, even when the first and second electrode portions are configured by other than the metal terminals, for example, by changing the thickness of the paste layer itself, the first and the same as in the case of the metal terminal fitting. It is also possible to form the second part on the outer surface. The coil device according to the modification as described above also has the same effect as the coil device according to the embodiment.

DESCRIPTION OF SYMBOLS 10 ... Coil apparatus 16 ... Flat core 20 ... Main body core 21 ... Shaft part 22 ... 1st end part 26 ... 2nd end part 23, 27 ... End surface 24, 28 ... Lower side surface 24a, 28a ... Convex surface 24b, 28b ... Concave surface 29 ... Upper side surface 30 ... Coil portions 31, 32, 33, 34 ... Wires 31a, 32a, 33a, 34a ... Wire first end portions 31b, 32b, 33b, 34b ... Wire second end portion 41 ... First electrode portion 42 ... 1st fixed surface 51 ... 2nd electrode part 52 ... 2nd fixed surface 42a ... Fixed end 43 ... Inner side surface 44, 54 ... Outer surface 44a, 54a ... 1st part 44aa, 44ab ... Area | region 44b, 54b ... 2nd part 46 56 ... Extension part A ... Center axis 70 ... Wire material 70a ... Excess part 80 ... Heater chip

Claims (7)

A magnetic core having a shaft portion and a magnetic core end connected to the shaft portion;
A coil portion formed by winding a wire around the shaft portion;
An electrode portion provided at the end of the magnetic core and made of a good conductor;
The electrode portion is provided on a side surface that does not intersect the central axis of the coil portion at the magnetic core end portion, and is a fixed surface to which a wire end portion of the wire is fixed, and the side surface of the magnetic core end portion, and the shaft portion And an outer surface provided at a position farther from the fixed surface,
The outer surface includes a first portion that is closer to the central axis than a fixed end to which the tip of the wire end on the fixed surface is fixed, and a second portion that is closer to the central axis than the first portion. A coil device characterized by comprising:   2. The coil device according to claim 1, wherein the center position of only the second portion is provided at a position closer to the shaft portion than the center position of the entire outer surface. Having at least two electrode parts including a first electrode part and a second electrode part,
The magnetic core has a pair of magnetic core end portions respectively connected to both end portions of the shaft portion,
One of the magnetic core end portions is provided with the first electrode portion having a first fixing surface which is the fixing surface to which the one wire end portion of the wire is fixed,
The second electrode portion having a second fixing surface which is the fixing surface to which the other wire end portion of the wire is fixed is provided at the other magnetic core end portion,
The side surface of the magnetic core end portion on which the first fixing surface is provided and the side surface of the magnetic core end portion on which the second fixing surface is provided are located on the same plane. The coil device according to claim 1 or claim 2.   The coil device according to any one of claims 1 to 3, wherein the fixed surface is inclined in a direction away from the central axis with respect to a direction from the shaft portion toward the magnetic core end portion. .   5. The coil device according to claim 4, wherein the wire end portion has an inclined tip end portion whose thickness in a direction orthogonal to the central axis decreases toward the tip end.   6. The coil device according to claim 1, wherein the electrode part is a metal terminal fitting. The metal terminal fitting has an inner surface that contacts the side surface of the magnetic core end,
The coil device according to claim 6, wherein the fixed surface is inclined with respect to the inner surface.

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