JP2006165460A - Surface-mounting coil and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface mounting coil which prevents the damage of an insulating material due to contact between the winding portion of a coil and its drawing portion when hot-press joining, and to provide its surface mounting coil manufacturing method. <P>SOLUTION: The surface mounting coil 10 includes a coreless coil 20 where both ends of α turns of a ribbon wire 12 are bent from the outermost portions 15a of the winding portion 15 to form the drawing portions 12a, 12b, a box-shaped core 25 having a recess 24, a covering core 28 fixedly bonded to its upper surface, an axial core 26 integral with the covering core 28, and terminal electrodes 29 attached to the box-shaped core 25. The surface mounting coil is constructed so that the coreless portion 18 of the coreless coil 20 is inserted into the axial core 26 holding a space S, and the ends of the drawing 12a, 12b are conductively joined on the terminal electrodes 29, 29 by hot-press, especially, the space between the drawing portion 12a, 12b and the outermost portion 15a is filled with an insulating resin 7, but the space S between the internal surrounding surface of the coreless coil 20 and the axial core 26 is not filled with an insulating resin. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention belongs to the technical field of a winding type surface mounting coil such as a choke coil surface mounted on a substrate of an electronic device.

  One of the winding type surface mount coils represented by a choke coil surface mounted on a substrate of an electronic device is a so-called power choke coil capable of flowing a large current of 1 ampere or more.

  As a surface mount coil such as this power choke coil, for example, a rectangular wire 12 of an insulation coated conductor in which a conductor 13 having a rectangular vertical cross section is covered with an insulating material 14 such as polyurethane resin as shown in FIG. As shown in an exploded perspective view for explaining the structure of a conventional choke coil, so-called α winding is performed in which two layers are wound in opposite directions from the inside to the outside, and current is passed through the conductor 13. The surface of the insulating material 14 of the flat wire 12 that has been heated and laminated is fused and fixed to integrate the entire winding portion 15, and both end portions of the flat wire 12 are respectively connected to the outermost peripheral portions of the winding portion 15. 15a is formed as an air core coil 20 formed with lead-out portions 12a and 12b drawn substantially flush with the upper surface of the winding portion 15, and this is formed with a recess 24 for accommodating the air core coil 20 and the Enclose recess 24 It is housed in the concave portion 24 of a box-shaped core 25 made of ferrite and provided with a pull-out groove 22 provided on the side wall 23 and leading to the outside from the concave portion 24, and from the bottom surface of the pull-out groove 22 of the side wall 23 of the box-shaped core 25 to the side wall The terminals of the lead portions 12a and 12b at both ends of the rectangular wire 12 of the air-core coil 20 are respectively connected to the pair of terminal electrodes 29 and 29 provided across the bottom surface of the box-shaped core 25 through the outer surface of the box-shaped core 25. It is placed so as to be positioned, and is crimped from above with a heater chip (not shown) heated to a high temperature of about 600 ° C. to 850 ° C. to evaporate the insulating material 14 of the terminal and crush the conductive wire (copper wire etc.) to the terminal electrode 29 A lid core (shaft core core with lid) 28 integrally provided with a core core portion 26 having a T-shaped longitudinal cross-section made of ferrite is formed by conducting thermocompression bonding that instantaneously joins and electrically connecting. There is a surface mount coil 30 having a structure in which the concave portion 24 is closed by covering the upper surface of the box-shaped core 25 so that the portion 26 passes through the air core portion 18 of the air core coil 20 and fixed with an adhesive (not shown).

  Further, as an example of a surface mount coil using the rectangular wire 12 having a structure similar to the surface mount coil 30 shown in FIG. 10, the following [Patent Document 1] includes (a) an exploded perspective view of FIG. b) A surface mount coil 40 having a structure as shown in the sectional view is shown.

  That is, an annular wire ring 32 having lead terminal portions 32a, 32b provided with through holes 33 is housed in a wire ring housing recess 36 of a ferrite or ceramic core case 35 having a terminal electrode 37, The lead terminal portions 32 a and 32 b are drawn out by being bent so as to be parallel to the bottom surface of the lead terminal portion lead-out groove portion, welded by the terminal electrode 37 and the solder 41, and axially centered in the center hole 38 of the annular wire ring 32. A core 34 (cylindrical magnetic body) is inserted and arranged, and a lid core 31 made of the same material as the core case 35 is provided thereon using an adhesive or the like.

JP-A-10-41152

  In the conventional surface mount coil 30, the conductive bonding between the terminal electrode 29 and the ends of the lead-out portions 12a and 12b of the air-core coil 20 is 600 ° C. instead of soldering that requires heating at about 200 ° C. to 250 ° C. The end of the flat wire 12 on the terminal electrode 29 was crushed and crushed during thermocompression because it was performed by thermocompression forming an alloy of the metal of the terminal electrode 29 and the metal of the conductor 13 at a high temperature of ˜850 ° C. The part is pushed to the winding part 15 side, and a phenomenon occurs in which the bent drawer parts 12a and 12b are urged and moved to the winding part 15 side. At this time, the pulled-out drawer portions 12a and 12b may come into contact with the outermost peripheral portion 15a of the winding portion 15 and be further pressed to damage the insulating material 14 at that portion.

  In this regard, in the surface mount coil 40 as shown in FIG. 11 of [Cited document 1], the conductive bonding method by soldering is particularly employed, and thus the lead-out portion 12a generated in the case of the conductive bonding method by thermocompression bonding. The problem of contact with the winding part 15 of 12b is unexpected.

  Here, the high reliability of the bonding strength and the advantage of working speed of the conductive bonding method of both ends of the lead wire portion of the winding by thermocompression bonding and the terminal electrode, the heat during reflow soldering of the electronic component to the electronic substrate Considering the problems of softening and remelting of soldered conductive joints of surface mount coils against the surface, it is considered that conductive bonding between the terminals and terminal electrodes of the surface mount coil leads by thermocompression will become the mainstream in the future. .

  Therefore, when adopting a conductive bonding method by thermocompression bonding, it is important to avoid the possibility of the occurrence of damage to the insulating material due to the contact between the drawn portions 12a and 12b and the winding portion 15.

  As a technique for avoiding the occurrence of damage to the insulating material, an insulating material is separately attached to the outermost peripheral portion 15a of the air core coil 20, or the entire periphery of the air core coil 20 housed in the recess 24 of the box core 25 is insulated with resin. Alternatively, it is conceivable to permeate and fix in an insulating solvent (hereinafter referred to as insulating resin or the like). The latter method has been consistent with the method of insulating a plate iron core and an entire coil by impregnating them with a varnish in a ballast or a transformer.

  However, when manufacturing surface mount coils, attaching the insulating material or immersing it in an insulating resin requires a separate process of attaching, dipping, curing, and assembling the ferrite core. Time is required and there is a great risk of quality defects.

  In addition, the above-described conventional technique of varnishing the entire coil to be immersed in the entire coil is used for the surface mount coil, and the entire inner and outer clearances between the box-shaped core 25 and the air-core coil 20 as in the present application are used. If the structure is such that the resin is filled and fixed, the stress is caused by the occurrence of strain due to temperature rise due to the difference in thermal expansion coefficient between the filled insulating resin and the box core 25 or the shaft core part 26. Since it is applied to the core 25 and the shaft core part 26, and especially in the case of a magnetic core such as a ferrite core, there is a concern about deterioration of magnetic properties, it cannot be adopted.

  Further, a technique for preventing damage to the insulating material by operating various conditions at the time of thermocompression bonding between the terminal electrode 29 and the ends of the lead wires 12a and 12b of the air-core coil 20 without using the above-described insulating resin or the like. However, it is not a reliable permanent measure.

  The present invention has been made in view of the above circumstances, and ensures that there is no risk of damage to the insulating material during the thermocompression bonding of the surface mount coil using the conductive bonding method of the terminal electrode and the winding (flat wire) by thermocompression bonding. It is an object of the present invention to provide a surface mounting coil and a method for manufacturing the surface mounting coil which are excellent in workability during manufacturing.

The present invention
(1) An air-core coil in which a rectangular wire covered with an insulating material is wound and laminated from the inside to the outside, a recessed portion that accommodates the air-core coil, and a side wall that surrounds the recessed portion, and leads from the recessed portion to the outside. A box-shaped core having a lead-out groove, and a flat core wire of the air-core coil provided from the bottom face of the lead-out groove on the side wall of the box-shaped core to the bottom face of the box-shaped core via the outer surface of the side wall. A pair of terminal electrodes to which the lead portions at both ends are joined by thermocompression bonding, an axial core core inserted into the center of the air core coil, and an empty space of the box core provided integrally or separately from the axial core core In a surface mount coil having a lid core that closes the recess in which the core coil is accommodated,
The gap portion between the lead-out portion of the air-core coil and the outermost peripheral portion of the winding portion is filled, and the gap between the inner peripheral surface of the air-core coil and the shaft core portion or the shaft core. The above-mentioned problem is solved by providing a surface mount coil characterized in that an insulating resin is filled and cured so as not to fill.

(2) As a method of manufacturing a surface mount coil,
Winding and laminating a rectangular wire covered with an insulating material from the inside to the outside,
A step of preparing a box-shaped core provided with a concave portion that accommodates the air-core coil and a drawing groove that is provided on a side wall that surrounds the concave portion and leads to the outside from the concave portion;
A step of preparing an axial core to be inserted into the center of the air-core coil, and a step of preparing a lid core for closing a concave portion in which the air-core coil of the box-shaped core is accommodated, or being inserted into the center of the air-core coil. A step of preparing the lidded shaft core integrally comprising a shaft core portion and a lid portion that closes the concave portion in which the air-core coil of the box-shaped core is accommodated;
Providing the box-shaped core with a terminal electrode extending from the bottom surface of the drawer groove on the side wall of the box-shaped core to the bottom surface of the box-shaped core via the outer surface of the side wall;
Inserting the air-core coil into the recess of the box-shaped core;
Before and after the step of inserting the air-core coil into the concave portion of the box-shaped core, the gap between the outermost peripheral portion of the winding portion of the air-core coil and the lead-out portion of the air-core coil is filled, and Applying a thermosetting insulating resin or an ultraviolet curable insulating resin so as not to reach the inner peripheral surface of the winding portion of the air-core coil;
A step of applying heat or ultraviolet irradiation to the applied insulating resin and curing it;
A step of thermocompression bonding the end portion of the lead portion of the air-core coil after the insulating resin is filled and cured in the gap between the outermost peripheral portion of the winding portion and the lead portion to the terminal electrode;
A step of inserting the axial core into the center of the air-core coil, and a step of closing and fixing the concave portion of the box-shaped core with the lid core, or the center of the core-core with the lid. A step of closing the concave portion of the box-shaped core with the lid portion of the shaft core core with lid and fixing with an adhesive while inserting the shaft core;
There is provided a method for manufacturing a surface mount coil characterized by having at least.

The surface mount coil and the manufacturing method thereof according to the present invention are configured as described above.
(1) At the time of conducting conductive bonding between the lead wire of the air-core coil and the terminal electrode by thermocompression bonding, the lead-out portion pushed out to the air-core coil side by thermocompression bonding and the outermost peripheral portion of the winding portion of the air-core coil are There is a risk of damage to the insulating material due to contact with the UV curable insulating resin or thermosetting insulating resin filled and cured in the gap between the lead-out portion of the air-core coil and the outermost peripheral portion of the winding portion. While being blocked, the pressing force is prevented by being diffused between the thermocompression bonding portion and the portion where the insulating resin is filled and cured and throughout the winding portion of the air-core coil.
(2) The air core coil is not completely buried and fixed in the concave portion of the box core with insulating resin or the like, but the insulating resin or the like is the outermost peripheral portion of the lead portion and the winding portion of the air core coil. Is filled and cured so as not to fill the gap between the inner peripheral surface of the air-core coil and the shaft core portion or the shaft core. When the lead-out part is pushed from one side or both sides to the winding part side, the entire air-core coil only moves or slightly deforms, and the pressing force acts on the shaft core part or the shaft core. In particular, the magnetic properties of the ferrite core are not adversely affected. Further, in the coil lead portion between the thermocompression bonding portion and the portion where the insulating resin is filled and cured, a part of the pressing force is relieved by causing the wire rod to bend in the thickness direction of the flat wire.
(3) It is particularly useful as a short-circuit permanent product for a power choke coil that allows a large current to flow.
(4) Before the thermocompression bonding process, a simple process of filling the space between the lead-out portion of the air-core coil and the outermost peripheral portion of the winding portion with an ultraviolet curable insulating resin or a thermosetting insulating resin and curing it is performed. Therefore, it is excellent in workability and has almost no effect on the cost and time required for the manufacturing process.
(5) By adding a step of filling and curing an ultraviolet curable insulating resin or a thermosetting insulating resin, an improvement in reliability and an improvement in manufacturing yield are realized.

  An embodiment of a surface mount coil and a method for manufacturing the same according to the present invention will be described with reference to the drawings. In addition, about the member equivalent to what is well-known in prior art as FIG.9, FIG.10, FIG.11 is shown with the same code | symbol.

  FIG. 1 is a cross-sectional view for explaining the structure of a surface mount coil according to the present invention. FIG. 2 is an enlarged view for explaining a state in the vicinity of the conductive joint portion by thermocompression bonding between the terminal electrode and the terminal of the lead portion of the air-core coil. FIG. 3 is a perspective view of a ferrite core used in the surface mount coil according to the present invention. FIG. 4 is a perspective view for explaining the attachment state of the terminal electrodes. FIG. 5 is a perspective view for explaining the structure of the air-core coil. FIG. 6 is a cross-sectional view for explaining the pressure and movement received by the lead portion of the air-core coil during the thermocompression bonding of the surface mount coil according to the present invention. FIG. 7 is a plan view showing a state where the assembly of the surface mount coil according to the present invention is completed. FIG. 8 is a sectional view for explaining the structure of the second embodiment of the surface mount coil according to the present invention.

  The surface mount coil 10 shown in FIG. 1 has a rectangular wire 12 of a predetermined length covered with an insulating material 14 such as polyurethane resin shown in FIG. 9 from the inside as shown in FIG. The outer surface is wound and laminated by so-called α winding, and the surface of the insulating material is fused and fixed by energization, and both ends of the rectangular wire 12 are wound as shown in FIG. 5B. An air core coil 20 formed by bending from the outermost peripheral portion 15a of the portion 15 to form lead portions 12a and 12b substantially flush with the upper surface of the winding portion 15, and the air core coil 20 shown in FIG. A box-shaped core 25 made of ferrite, ceramics, or the like, provided with a recess 24 for storing the groove 24 and a lead-out groove 22 provided on the side wall 23 surrounding the recess 24 and leading to the outside, and the side wall 23 of the box-shaped core 25 Of the drawer groove 22 A pair of lead-out portions 12a and 12b at both ends of the flat wire 12 of the air-core coil 20 that are thermocompression-bonded to each other from the surface to the bottom surface of the box-shaped core 25 through the outer surface of the side wall 23. Terminal electrodes 29, 29, an axial core 26 inserted into the center of the air-core coil 20, and the box shape provided integrally with the axial core 26 (see FIG. 3) or separately (see FIG. 11). A lid core 28 made of ferrite, ceramics, or the like that closes the recess 24 in which the air core coil 20 of the core 25 is housed, and the air core portion 18 of the air core coil 20 is the box core 25 or the lid core. 28 is inserted into a shaft core portion 26 provided integrally with 28 or a separate shaft core 34, and the ends of the lead-out portions 12 a and 12 b are electrically bonded to the terminal electrodes 29 and 29 by thermocompression bonding, respectively. In particular, as shown in FIG. 1 or FIG. 2, a gap portion between the lead-out portions 12 a and 12 b of the air-core coil 20 and the outermost peripheral portion 15 a of the winding portion 15. And an insulating resin (ultraviolet curable insulating resin or thermosetting resin) so as not to fill a gap S between the inner peripheral surface of the air-core coil 20 and the shaft core portion 26 or the shaft core 34. Insulating resin) 7 is applied and filled by a dispenser 6 or the like, and is characterized by being cured by ultraviolet irradiation or heating.

  According to the above structure, as shown in FIG. 2, the terminal electrode 29 and the lead portion 12b (and 12a) of the air-core coil 20 are connected to the terminal by the heater chip 5 heated to a high temperature of 600 ° C. to 850 ° C. When thermocompression forming an alloy of the metal of the electrode 29 and the metal (generally copper) of the conductive wire 13 of the flat wire 12, the end of the flat wire 12 on the terminal electrode 29 is crushed as shown by a one-dot chain line. The collapsed portion is pushed toward the winding portion 15 and the pulling portion 12b (12a) is urged and moved (flexed) toward the winding portion 15 with the pressing force in the direction of arrow F. However, since the ultraviolet curable or thermosetting insulating resin 7 is filled and cured in the gap between the winding portion 15 and the outermost peripheral portion 15a before the thermocompression bonding, the drawn out drawing portion 12b is pushed out. (12a) is the outermost peripheral part of the winding part 15 Not in contact with 5a, damage to the winding unit 15 side does not occur, insulation is being held. At this time, the pressing force also serves to disperse the entire wound portion 15 of the air-core coil 20 by the filled and cured insulating resin 7.

  The extruded portion 12b (12a) that has been pushed out rises up as indicated by the alternate long and short dash line, or the winding portion 15 is pushed to the center as it is. At this time, the air-core coil 20 is not completely buried and fixed with an insulating resin or the like in the recess 24 of the box-shaped core 25, but the outermost periphery 15 a of the winding portion 15 and the recess of the box-shaped core 25. Since the gap S is provided between the inner wall of the inner wall 24 and the inner periphery of the air core portion 18 and the shaft core portion 26 or the shaft core 34, the drawn portions 12 a and 12 b at both ends of the air core coil 20 are formed by thermocompression bonding. Even when the coil is pushed from one side or both sides to the winding part 15 side, the entire air-core coil 20 is moved or slightly deformed into an ellipse. The pressing force does not work, and in particular in the case of a magnetic core such as a ferrite core, there is no adverse effect on the magnetic properties.

Next, the manufacturing method of the surface mounting coil using the thermocompression bonding for the conductive bonding between the terminal electrode 29 and the rectangular wire 12 of the winding like the surface mounting coil 10 includes at least the following steps (a) to (h). It consists of
(A) A step of winding and laminating a flat wire covered with an insulating material from the inside to the outside.

This is because, for example, a flat wire 12 in which a conductive wire 13 (copper, gold, silver, nickel, aluminum, cobalt, or an alloy thereof) as shown in FIG. 9 is coated with an insulating material 14 such as polyurethane resin or polyester resin is used. As shown in FIG. 5, concentric circles are formed in two concentric circles in opposite directions from the center (so-called α winding), and if necessary, the coil 14 is energized to fuse the insulating material 14 and solidify. An air core in which both ends of the flat wire 12 are bent from the outermost peripheral portion 15a of the winding portion 15 and drawn portions 12a and 12b are formed so as to be substantially flush with the upper surface of the winding portion 15. This is a manufacturing process of a coil body for making the coil 20. The method of winding the rectangular wire 12 includes other than the α winding. For example, like the annular wire ring 32 of the surface mount coil 40 of the prior art, one drawer portion 32a is simply drawn out from the inside to the outside and pulled out from the inner peripheral surface, and the other drawer portion is drawn. An annular wire ring 32 (air core coil) having a structure in which 32b is drawn from the outermost peripheral surface is also within the range of the present invention.
(B) a step of preparing a box-shaped core provided with a recess for accommodating the air-core coil and a lead-out groove provided on the side wall surrounding the recess and leading to the outside from the recess, and a shaft inserted into the center of the air-core coil A step of preparing a core, and a step of preparing a lid core for closing a recess in which the air-core coil of the box-shaped core is accommodated, or a shaft core portion inserted into the center of the air-core coil and the box-shaped core A step of preparing the lidded core core integrally provided with a lid portion for closing the concave portion in which the air-core coil is accommodated.

  This includes a box-shaped core 25 made of ferrite or ceramics having a recess 24 for accommodating the air-core coil 20 as shown in FIG. 3, a shaft core portion 26 inserted in the center of the air-core coil 20, and the A pair of cores comprising the lid-shaped core core 28 integrally including the box-shaped core 25 that closes the recess 24 in which the air-core coil 20 of the box-shaped core 25 is accommodated and the lid portion 27 of the same material. It is a core manufacturing process which shape | molds. Alternatively, the box-shaped core 25, a columnar shaft core 34 made of the same material as the box-shaped core 25 inserted in the center of the air-core coil 20 as shown in FIG. This is a core manufacturing process for forming a pair of cores that are formed in the box-shaped core 25 and close the recess 24 in which the air-core coil 20 of the box-shaped core 25 is accommodated, and the lid core 31 of the same material.

The core is manufactured, for example, by putting a mixed material containing ferrite as a main component into a mold and firing it, or cutting a ferrite fired body.
(C) A step of providing a terminal electrode extending from the bottom surface of the lead-out groove on the side wall of the box-shaped core to the bottom surface of the box-shaped core via the outer surface of the side wall.

As shown in FIG. 4, for example, a pair of terminal electrodes 29 made of a copper frame subjected to nickel plating, tin plating, or the like is provided on the box-shaped core 25, and the bottom surface of the lead groove 22 on the side wall 23 of the box-shaped core 25. And is attached to the bottom of the box-shaped core 25 through the outer surface of the side wall 23.
(D) A step of inserting the air-core coil into the recess of the box-shaped core.

This is a step of inserting the air core coil 20 into the recess 24 of the box-shaped core 25 as shown in FIG. 6A, and the end portions of the lead-out portions 12a and 12b of the air core coil 20 Are placed on the upper surfaces of the terminal electrodes 29 and 29, respectively. The inserted air-core coil 20 is completely accommodated in the recess 24.
(E) Filling the gap between the outermost peripheral part of the winding part of the air core coil and the lead part of the air core coil before and after the step (d) of inserting the air core coil into the recess of the box core And applying a thermosetting insulating resin or an ultraviolet curable insulating resin so as not to reach the inner peripheral surface of the winding portion of the air-core coil.

This is a process unique to the present invention. As shown in FIGS. 6A and 6B, before or after the air-core coil 20 is housed in the recess 24 of the box-shaped core 25, An insulating resin (ultraviolet curable insulating resin or thermosetting insulating resin is used in the gap between the lead portions 12a and 12b of the air-core coil 20 and the outermost peripheral portion 15a of the winding portion 15, and preferably has good heat resistance. This is a step of applying an appropriate epoxy resin) 7 with a dispenser 6 or the like. It should be noted here that the filling and hardening of the insulating resin 7 does not extend over the entire gap between the air core coil 20 and the concave portion 24 of the box core 25, but the inner peripheral surface of the winding portion 15 of the air core coil 20. It is a point that has not been reached. The stress caused by the difference in thermal expansion coefficient between the insulating resin 7 filled and cured by this structure and the core material does not reach the axial core part 26 or the axial core 34.
(F) A step of heating or irradiating the applied insulating resin to cure.

If the applied insulating resin 7 is, for example, an epoxy resin, it is quickly cured by irradiation with ultraviolet rays.
(G) A step of thermocompression bonding the end portion of the lead portion of the air-core coil after the insulating resin is filled and cured in the gap between the outermost peripheral portion of the winding portion and the lead portion to the terminal electrode.

As shown in FIG. 2, this is about 600 ° C. to 850 ° C. with the terminals of the flat wire lead portions 12 a and 12 b of the air-core coil 20 positioned on the terminal electrodes 29 and 29, respectively. This is a thermocompression bonding process in which conductive bonding is performed by thermocompression bonding of the heater chip 5 heated to a high temperature. After the thermocompression bonding, the crushed portion like a one-dot chain line moves to the left and right, and the lead-out portions 12a and 12b bend and the pressing force acts in the direction of arrow F, but the insulating resin 7 that is filled and hardened is interposed. The danger that 12a, 12b contacts the outermost peripheral part 15a of the winding part 15 of the air-core coil 20, and the insulating material of the part is damaged is prevented.
(H) The step of inserting the shaft core into the center of the air core coil, the step of closing the concave portion of the box-shaped core with the lid core and bonding and fixing, or the shaft core of the core core with lid at the center of the air core coil The step of closing the concave portion of the box-shaped core with the lid portion of the shaft core with lid and fixing it with an adhesive.

  This is a core assembly process. Finally, for example, as shown in the cross-sectional view of FIG. 1, the air core coil is housed in the concave portion 24 of the box-shaped core 25 and the lead portions 12a and 12b are conductively joined to the terminal electrode 29 by thermocompression bonding. When the shaft core 26 of the cover core core 28 is inserted into the air core section 20 of the cover 20, the recess 24 of the box-shaped core 25 is closed with the cover section 27 of the cover core core 28 and its peripheral portion. Is fixed with the box-shaped core 25 and the adhesive 9.

  In the manufacturing method of the surface mount coil of this invention, it has at least each process of said (i)-(h). In addition to the above steps, the surface mount coil is completed through a display printing process and a characteristic selection taping process in which the product number and the like are printed on the upper surface of the lid portion 27 or the lid core 31 in the final line.

  As can be seen from the above manufacturing process, the process added to the conventional process for preventing damage to the insulation material of the air-core coil during thermocompression which is the gist of the present invention is the insulating resin 7 (ultraviolet curable insulating resin). Or a process of applying and curing a thermosetting insulating resin), which is extremely simple and excellent in workability, and its action is a measure for preventing damage to the insulating material due to contact with the winding portion 15 of the air-core coil 20. A reliable and permanent effect can be obtained.

  In addition, as the ultraviolet curable insulating resin or the thermosetting insulating resin of the insulating resin 7, an epoxy resin which is excellent in heat resistance and advantageous in workability is optimal as a thermosetting and ultraviolet curable resin. Of course, other thermosetting or UV curable resins having sufficient heat resistance against heat conduction during thermocompression bonding may be used.

  Next, the surface mount coil 50 of the second embodiment of the surface mount coil according to the present invention shown in FIG. 8 is an application example in the case corresponding to the conventional surface mount coil 40 of FIG.

  In FIG. 8, the air-core coil 21 is not α-wound, but is simply a flat wire 12 wound and laminated in one step from the inner side to the outer side. The lead portion 12b is drawn from the outside, and in this case, in particular, unlike the previous embodiment, the insulating resin 7 is used for the lead portion 12a drawn from the inner side of the winding portion 15. It is filled and solidified in a gap at the edge part where 12a and the outermost peripheral part 15a of the winding part 15 are in contact (just below the drawer part 12a).

  Also in the surface mount coil 50 having the above structure, the lead portions 12a and 12b and the outermost peripheral portion 15a of the winding portion 15 come into contact with each other due to the movement by the pressing force at the time of thermocompression bonding, and the insulating material may be damaged. Since the insulating resin 7 is filled and solidified in advance, the same effects as those of the surface mount coil 10 can be obtained. Needless to say, the surface mounting coil 50 can be manufactured by a method of manufacturing a surface mounting coil having at least the steps (a) to (h).

  In addition, as a precaution, in the method for manufacturing a surface mount coil according to the present invention, before the conductive bonding step by thermocompression bonding between the lead portion of the air core coil and the terminal electrode, the lead portion of the air core coil and It is a requirement to apply and cure a UV curable insulating resin or a thermosetting insulating resin in the gap between the winding portion and the outermost peripheral portion, and the order of other steps can be changed as appropriate. .

It is sectional drawing for demonstrating the structure of the surface mount coil which concerns on this invention. . It is an enlarged view for demonstrating the state of the conductive junction part vicinity by the thermocompression bonding with the terminal electrode and the terminal of the extraction | drawer part of an air core coil. It is a perspective view of the ferrite core used with the surface mount coil which concerns on this invention. It is a perspective view for demonstrating the attachment state of a terminal electrode. It is a perspective view for demonstrating the structure of an air-core coil. It is sectional drawing for demonstrating the pressure and movement which the drawer | drawing-out part of the air-core coil at the time of thermocompression bonding of the surface mount coil which concerns on this invention. It is a top view which shows the state which the assembly of the surface mount coil which concerns on this invention was completed. It is sectional drawing for demonstrating the structure of 2nd Embodiment of the surface mount coil which concerns on this invention. It is a perspective view which shows the structure of the insulation coating conducting wire called a flat wire. It is a disassembled perspective view for demonstrating the structure of the conventional choke coil. It is (a) disassembled perspective view and (b) sectional drawing of the surface mount type coil described in [cited document 1].

Explanation of symbols

5 Heater chip
6 Dispenser
7 Insulating resin (UV curable insulating resin or thermosetting insulating resin)
9 Adhesive 10, 30, 40, 50 Surface mount coil
12 Flat wire 12a, 12b Drawer
13 Conductor
14 Insulation material
15 winding part 15a outermost part
18 Air core 20, 21 Air core coil
22 Drawer groove
23 Side wall
24 recess
25 box core
26 Shaft core part
27 Lid
28 Core core with lid 29, 37 Terminal electrode
31 lid core
34 Shaft core
F Pressing force in the direction of the arrow
S clearance

Claims (2)

An air-core coil in which a rectangular wire covered with an insulating material is wound and laminated from the inside to the outside, a recess that accommodates the air-core coil, and a drawing groove that is provided on a side wall that surrounds the recess and leads from the recess to the outside A box-shaped core provided between the bottom of the box-shaped core and the bottom surface of the box-shaped core through the outer surface of the side wall, and both ends of the flat wire of the air-core coil. A pair of terminal electrodes, each of which is thermocompression-bonded, an axial core core inserted into the center of the air core coil, and an air core coil of the box core provided integrally or separately from the axial core In a surface mount coil having a lid core that closes the recessed portion accommodated therein,
The gap portion between the lead-out portion of the air-core coil and the outermost peripheral portion of the winding portion is filled, and the gap between the inner peripheral surface of the air-core coil and the shaft core portion or the shaft core. The surface mount coil is characterized in that the insulating resin is filled and cured so as not to fill. Winding and laminating a rectangular wire covered with an insulating material from the inside to the outside,
A step of preparing a box-shaped core provided with a concave portion that accommodates the air-core coil and a drawing groove that is provided on a side wall that surrounds the concave portion and leads to the outside from the concave portion;
A step of preparing an axial core to be inserted into the center of the air-core coil, and a step of preparing a lid core for closing a concave portion in which the air-core coil of the box-shaped core is accommodated, or being inserted into the center of the air-core coil. A step of preparing the lidded shaft core integrally comprising a shaft core portion and a lid portion that closes the concave portion in which the air-core coil of the box-shaped core is accommodated;
Providing the box-shaped core with a terminal electrode extending from the bottom surface of the drawer groove on the side wall of the box-shaped core to the bottom surface of the box-shaped core via the outer surface of the side wall;
Inserting the air-core coil into the recess of the box-shaped core;
Before and after the step of inserting the air-core coil into the concave portion of the box-shaped core, the gap between the outermost peripheral portion of the winding portion of the air-core coil and the lead-out portion of the air-core coil is filled, and Applying a thermosetting insulating resin or an ultraviolet curable insulating resin so as not to reach the inner peripheral surface of the winding portion of the air-core coil;
A step of applying heat or ultraviolet irradiation to the applied insulating resin and curing it;
A step of thermocompression bonding the end portion of the lead portion of the air-core coil after the insulating resin is filled and cured in the gap between the outermost peripheral portion of the winding portion and the lead portion to the terminal electrode;
A step of inserting the axial core into the center of the air-core coil, and a step of closing and fixing the concave portion of the box-shaped core with the lid core, or the center of the core-core with the lid. A step of closing the concave portion of the box-shaped core with the lid portion of the shaft core core with lid and fixing with an adhesive while inserting the shaft core;
A method for manufacturing a surface mount coil, comprising:

Images