JP4044566B2 - Surface mount inductor and method of manufacturing the same - Google Patents

Description

  The present invention relates to a surface mount inductor used as a choke coil and other coil components and a method for manufacturing the same.

  Conventionally, in a surface mount type coil device such as a transformer having a ring core and a drum core, a base for supporting the ring core and the drum core is provided, and a terminal provided at a side end portion of the base is penetrated from the lower surface side to the upper surface side of the base. Formed on the upper surface of the base, a portion projecting outward on the upper surface of the base, a portion located on the lower surface side of the base, and a portion located on the side surface of the base, and attached as if wrapped around the side surface portion A technique is known (for example, refer to Patent Document 1).

  A terminal portion of the coil wound around the drum core is connected to the portion of the upper surface of the base that protrudes outward, and the portion located on the lower surface of the base is used as a surfaced terminal portion. Yes.

The drum core is positioned by fitting one of the flanges to a receiving portion formed of a recess provided on the upper surface of the base. The ring core has a pair of convex edges and is positioned by fitting these convex edges to the concave portions of the base formed on both sides of the receiving portion.
Microfilm of No. 63-60419 (No. 1-163306) (page 8, line 8-page 10, line 4, FIG. 1 to FIG. 5)

  The structure in which the terminal is attached so as to be wound around the side edge of the base is excellent in that the terminal does not fall off during assembly of the product even when the product is downsized. However, in patent document 1, while positioning a ring core and a drum core on the basis of a base, the terminal is attached to this base. For this reason, a base that overlaps the thickness direction with respect to the ring core and the drum core is indispensable, and the number of parts is large, and the thickness of the entire product is increased by this base, so that it is not suitable for thinning.

  In addition, a magnetic gap is formed between the ring core and the drum core, but both the accuracy of fitting the ring core to the base and the accuracy of fitting the drum core to the base affect the size of the magnetic gap, and the effect. Increases as the product becomes smaller. As a result, the variation in inductance may increase due to the variation in magnetic gap when the product is miniaturized.

  An object of the present invention is to provide a surface-mount inductor that can reduce the number of components, is suitable for thinning, and can suppress variations in inductance, and a method for manufacturing the same.

  In order to achieve the above object, a surface mount type inductor according to a first aspect of the present invention includes a ring core, an outer peripheral contact portion along the outer surface of the ring core, and a bend from the outer peripheral contact portion along one end surface of the ring core. And the inner peripheral contact portion bent along the inner surface of the ring core from the imposition portion, and the outer peripheral contact portion is bent along the other end surface of the ring core and protrudes outward. At least one of a plurality of terminals formed of coil connecting portions and flanges respectively provided at both ends in the axial direction of the winding drum is brought into contact with the inner peripheral contact portions of the respective terminals, and portions other than the contact portions and the ring core A drum core disposed inside the ring core with a magnetic gap between the coil core and a coil terminal portion is wound around the winding drum, and the coil terminal portion is It is provided with a coil which is electrically and mechanically connected to the connecting portion.

  In the present invention, the drum core is directly positioned inside the ring core by contacting the flange portion of the drum core with the inner peripheral contact portion of the plurality of terminals attached to be wound around the ring core. As the variation in the magnetic gap formed on the substrate is suppressed, the variation in inductance can be suppressed. And by the above-mentioned positioning using a terminal, while being able to reduce the part which overlaps in the thickness direction of a drum core and a ring core, it can form thinly in connection with it.

  As a preferred form of the present invention, in the surface mount inductor according to the invention of claim 2, the ring core has a plurality of terminal mounting portions, and at least the inner side surface of the inner side surface and the outer side surface of these mounting portions is provided. It is formed in a plane, and the terminal is attached to each of the terminal attaching portions. The present invention is preferable in that the terminal fitted in the terminal mounting portion of the ring core at the time of assembly can be prevented from moving in the circumferential direction of the ring core.

  As a preferred form of the present invention, in the surface mount type inductor according to the invention of claim 3, one end surface of the drum core closer to the imposition portion and the imposition portion are connected in a flush manner. The present invention is preferable in that the inductor can be arranged more stably on the printed wiring board.

  In order to achieve the above object, a method for manufacturing a surface mount inductor according to a fourth aspect of the present invention includes an outer peripheral contact portion, an imposition portion bent at a right angle from the outer peripheral contact portion, and the imposition portion. An inner peripheral contact portion that is bent at a right angle so as to be parallel to the outer peripheral contact portion, and a coil connecting portion that is continuous with the inner peripheral contact portion along a bending direction of the inner peripheral contact portion with respect to the imposition portion An insertion step in which a terminal formed of the outer peripheral contact portion, the imposition portion, and the groove formed by the inner peripheral contact portion and a ring core are fitted to the ring core, and the coil connection portion is impositioned A terminal bending step in which the terminal is held by the ring core by bending the ring core in parallel with a portion, and a drum core around which a coil is wound is disposed inside the ring core, and the flange portion of the drum core is disposed in the inner portion. A drum fitting step of bringing a magnetic gap between a portion other than the contact portion and the inner periphery of the ring core, and an electrical and mechanical connection between the coil terminal portion of the coil and the coil connection portion. And a connecting step of connecting to.

  In the method of the present invention, since the terminal is held so as to be wound around the ring core by the insertion step and the terminal bending step, the terminal does not fall off from the ring core in the subsequent steps, and the productivity is good. Further, in the drum fitting process, the drum core around which the coil is wound using the terminals held by the ring core can be directly positioned with respect to the ring core to form a predetermined magnetic gap between the cores. Therefore, according to the method of the present invention, it is possible to manufacture a surface mount inductor that can reduce the number of components, is suitable for thinning, and can suppress variations in inductance.

  In order to achieve the above object, a method for manufacturing a surface-mounted inductor according to a fifth aspect of the present invention includes a terminal body in which a pair of terminals are integrally continuous at a bridge portion, and the pair of terminals includes: An outer peripheral contact portion, an imposition portion bent at a right angle from the outer peripheral contact portion, an inner peripheral contact portion bent at a right angle from the imposition portion so as to be parallel to the outer peripheral contact portion, and the inner periphery A groove formed by the outer peripheral contact portion, the imposition portion, and the inner peripheral contact portion, comprising a coil connecting portion that is continuous with the inner peripheral contact portion along a bending direction of the contact portion with respect to the imposition portion; An insertion step of fitting a ring core and combining the ring core and the terminal body, a cutting step of cutting the bridge portion side portion of the coil connection portion to remove the bridge portion, and the coil connection portion Surface A terminal bending step in which the terminal is held by the ring core by being bent in parallel with a portion, and a drum core around which a coil is wound is disposed inside the ring core, and a flange portion of the drum core is disposed on the inner peripheral contact portion And a drum fitting step of providing a magnetic gap between the portion other than the contact portion and the inner periphery of the ring core, and electrically and mechanically connecting the coil terminal portion of the coil to the coil connection portion. Connecting step.

  In the method of the present invention, since the terminal is held so as to be wound around the ring core by the insertion process, the cutting process, and the terminal bending process, the terminal does not fall off from the ring core in the subsequent processes, and the productivity is good. Moreover, by providing a cutting step, the insertion of the terminals into the ring core requires a single terminal body in which the pair of terminals are integrally connected at the bridge portion without the need to insert the pair of terminals separately. Since it only has to be inserted, manufacturability is also good in this respect. Further, in the drum fitting process, the drum core around which the coil is wound using the terminals held by the ring core can be directly positioned with respect to the ring core to form a predetermined magnetic gap between the cores. Therefore, according to the method of the present invention, it is possible to manufacture a surface mount inductor that can reduce the number of components, is suitable for thinning, and can suppress variations in inductance.

  According to the first to third aspects of the present invention, it is possible to provide a surface mount inductor that can reduce the number of components, is suitable for thinning, and can suppress variations in inductance.

  According to the fourth and fifth aspects of the present invention, it is possible to provide a method for manufacturing a surface mount inductor that can reduce the number of components, is suitable for thinning, and can suppress variations in inductance.

  A first embodiment of the present invention will be described with reference to FIGS.

  7 and 8, reference numeral 1 denotes a surface mount type choke coil. The choke coil 1 includes a ring core 2, a plurality of, for example, a pair of terminals 3, 4, a drum core 7, and a coil 8.

  The ring core 2 is formed by compression-molding a magnetic material, preferably a ferromagnetic powder, into a ring shape, for example, a substantially square frame shape, and the cross-sectional shape of each part in the radial direction is a quadrangle as shown in FIG. As shown in FIG. 2 and the like, the ring core 2 has a plurality of pairs of terminal mounting portions 2a positioned at a distance of, for example, 180 degrees.

  The inner side surface 2b of these terminal mounting portions 2a, that is, the side surface facing the inner space of the ring core 2 is formed as a flat surface. Similarly, the outer surface 2c of the terminal mounting portion 2a, that is, the side surface facing the outside of the ring core 2 is formed in a plane parallel to the inner surface 2b. The outer surface may be formed with a surface other than a flat surface, but is preferably a flat surface in order to reduce the size of the product.

  As shown in FIG. 2, the inner peripheral surface of the ring core 2 is formed by a pair of inner side surfaces 2b formed of a plane and a pair of arcuate surfaces 2d extending therebetween. For this reason, the inner surface 2b and the arcuate surface 2d are continuous with each other forming an angle 2f.

  The terminals 3 and 4 are the same, and the terminal 3 is attached to be wound around one terminal attachment portion 2a, and the terminal 4 is attached to be wound around the other terminal attachment portion 2a. That is, the terminal 3 has the outer periphery contact part 3a, the imposition part 3b, the inner periphery contact part 3c, and the coil connection part 3d. Similarly, the terminal 4 has the outer periphery contact part 4a, the imposition part 4b, the inner periphery contact part 4c, and the coil connection part 4d. In order to improve the wettability with the solder when surface-mounting the choke coil 1 on a printed wiring board (not shown), the terminals 3 and 4 have a plating layer (not shown) on the entire surface thereof.

  The shapes of the terminals 3 and 4 before being attached to the terminal attaching portion 2a are shown in FIG.

  As for the terminal 3, the imposition portion 3b is bent at a right angle from the outer peripheral contact portion 3a, the inner peripheral contact portion 3c is bent at a right angle from the imposition portion 3b, and the coil connection portion 3d is an inner peripheral contact. Without being bent with respect to the portion 3c, the inner peripheral contact portion 3c is continuous straight in the bending direction with respect to the imposition portion 3b. In FIG. 3, the inner peripheral contact portion 3c and the outer peripheral contact portion 3a facing each other are parallel to each other, and a U-shaped groove 3e is formed by these and the imposition portion 3b.

  With respect to the terminal 4, the imposition portion 4b is bent at a right angle from the outer peripheral contact portion 4a, the inner peripheral contact portion 4c is bent at a right angle from the imposition portion 4b, and the coil connection portion 4d is an inner peripheral contact. Without being bent with respect to the portion 4c, the inner peripheral contact portion 4c continues straight in the bending direction with respect to the imposition portion 4b. In FIG. 3, the inner peripheral contact portion 4c and the outer peripheral contact portion 4a facing each other are parallel to each other, and a U-shaped groove 4e is formed by these and the imposition portion 4b.

  The inner peripheral contact portions 3c and 4c are approximately equal to the width of the inner side surface 2b of the terminal mounting portion 2a, and the width w (see FIG. 1) of the grooves 3e and 4e is approximately equal to the thickness of the terminal mounting portion 2a. In order to facilitate bending of the coil connecting portions 3d and 4d, their widths are formed narrower than the widths of the inner peripheral contact portions 3c and 4c (see FIG. 3). Further, the lengths of the coil connecting portions 3d and 4d are longer than the thickness of the terminal mounting portion 2a.

  The terminal 3 is wound around the terminal mounting portion 2a by fitting the groove 3e to one terminal mounting portion 2a and then bending the coil connection portion 3d toward the outside of the ring core 2. As a result, the outer peripheral contact portion 3a is along the outer surface 2c of one terminal mounting portion 2a, the imposition portion 3b is along one end surface of the one terminal mounting portion 2a, and the inner peripheral contact portion 3c is one terminal. Along with the inner side surface 2b of the mounting portion 2a, a coil connection portion 3d is provided along the other end surface of one terminal mounting portion 2a.

  After the terminal 4 is fitted into the other terminal mounting portion 2a, the terminal 4 is bent toward the outside of the ring core 2 and is wound around the other terminal mounting portion 2a symmetrically with the terminal 3. It has been. Accordingly, the outer peripheral contact portion 4a is along the outer surface 2c of the other terminal mounting portion 2a, the imposition portion 4b is along one end surface of the other terminal mounting portion 2a, and the inner peripheral contact portion 4c is further connected to the other terminal. Along with the inner side surface 2b of the mounting portion 2a, a coil connection portion 4d is provided along the other end surface of the other terminal mounting portion 2a.

  The drum core 7 is formed by compression-molding a magnetic material, preferably a ferromagnetic powder, and integrally has circular flanges 7b and 7c at both ends in the axial direction of the winding drum 7a as shown in FIG. A coil 8 is wound around a winding drum 7 a of the drum core 7. One coil terminal portion 8a and the other coil terminal portion 8b of the coil 8 are drawn out of the drum core 7, respectively.

  The drum core 7 around which the coil 8 is wound is inserted into the inner space of the ring core 2. The inserted drum core 7 is disposed in the inner space of the ring core 2 with its flanges 7b and 7c contacting the inner peripheral contact portions 3c and 4c of the terminals 3 and 4 as shown in FIG. That is, the drum core 7 is positioned with respect to the ring core 2 by the contact between the two positions at the positions sandwiching the drum core 7 and is disposed in the inner space of the ring core 2. As shown in FIG. 7, the end surface 7 d closer to the flange portion 7 c of the drum core 7 is continuous with the imposition portions 3 c and 4 c of the terminals 3 and 4 attached to the ring core 2.

  An arc-shaped magnetic gap G is formed between the flanges 7b and 7c of the drum core 7 and the inner peripheral surface of the ring core 2 except for the two contact portions as shown in FIG. An adhesive (not shown) is supplied to these magnetic gaps G. 7 and 8, the coil terminal portion 8a is electrically and mechanically connected to the coil connection portion 3d of the terminal 3, and the coil terminal portion 8b is electrically and mechanically connected to the coil connection portion 4d of the terminal 4. Connected. Therefore, the drum core 7 is held on the ring core 2 by connecting the coil terminal portions 8a and 8b to the coil connecting portions 3d and 4d and bonding the ring core 2 and the drum core 7 with an adhesive. The coil terminal portions 8a and 8b can be connected to the coil connection portions 3d and 4d by soldering or welding. In this case, it is preferable that the coil terminal portions 8a and 8b are entangled with the coil connecting portions 3d and 4d.

  To illustrate the size of the choke coil 1 having the above configuration, the thickness H (see FIG. 7) is 1.2 mm, and the length L of each side in the vertical and horizontal directions (see FIG. 8) is 3.2 mm. The choke coil 1 thus miniaturized is used by being surface-mounted on a printed wiring board (not shown) as a chip component. In that case, the imposition portions 3d and 4d of the terminals 3 and 4 are bonded to the land of the wiring pattern of the printed wiring board using cream solder. In this soldering joining, the imposition portions 3d and 4d and the one end surface 7d of the drum core 7 are connected to be flush with each other, so that the choke coil 1 can be disposed more stably on the printed wiring board.

  The choke coil 1 has the flanges 7b and 7c of the drum core 7 disposed inside the ring core 2 in contact with the inner peripheral contact portions 3c and 4c of the terminals 3 and 4 attached so as to be wound around the ring core 2, The drum core 7 is positioned directly inside the ring core 2. For this reason, a predetermined magnetic gap G is formed between the drum core 7 and the ring core 2. As a result, variation in the arrangement of the drum core 7 with respect to the ring core 2 of the manufactured choke coil 1 can be suppressed, and variations in inductance of the manufactured choke coil 1 can be suppressed.

  Then, by the positioning described above using the terminals 3 and 4, it is not necessary to arrange the positioning members in the thickness direction of the drum core 7 and the ring core 2. Therefore, the number of parts can be reduced and the cost can be reduced, and the choke coil 1 can be formed thin.

  Further, the inner peripheral contact portions 3c and 4c of the terminals 3 and 4 of the choke coil 1 are along the inner side surface 2b formed of a plane of the terminal mounting portion 2a, and the inner side surface 2b and the arcuate surface 2d are formed. Both edges of the inner peripheral contact portions 3c and 4c are caught at the corner 2f. Thereby, at the time of manufacture of the choke coil 1, it is possible to eliminate the possibility that the terminals 3, 4 fitted to the terminal mounting portion 2 a of the ring core 2 shift in the circumferential direction of the ring core 2.

  Next, a method for manufacturing the choke coil 1 will be described. This manufacturing method includes an insertion process, a terminal bending process, a drum fitting process, and a connection process, and an adhesion process is added if necessary.

  In the insertion step, the grooves 3e and 4e of the terminals 3 and 4 are formed in the terminal mounting portion 2a of the ring core 2 from the state where the terminals 3 and 4 shown in FIG. 3 are opposed to the ring core 2 as shown in FIG. And the terminals 3 and 4 are combined with the ring core 2. In this case, the terminals 3 and 4 may be inserted into the ring core 2, or conversely, the ring core 2 may be inserted into the terminals 3 and 4.

  This combined state is shown in FIG. In this state, the outer peripheral contact portions 3a and 4a of the terminals 3 and 4 are brought into contact with the outer surface 2c of the corresponding terminal mounting portion 2a, and the facing portions 3b and 4b of the terminals 3 and 4 are connected to the corresponding terminal mounting portion 2a. It is attached to one end face. Further, the inner peripheral contact portions 3c, 4c of the terminals 3, 4 are attached to the inner side surface 2b of the corresponding terminal mounting portion 2a, and the coil connecting portions 3d, 4d of the terminals 3, 4 pass through the ring core 2 and extend upward. Protruding.

  In this insertion step, it may be added that a thermosetting adhesive is applied to at least a part of the inner surfaces of the grooves 3e and 4e, and heat is applied after the fitting to cure the adhesive. In this case, it is preferable in that the terminals 3 and 4 fitted to the ring core 2 in the subsequent steps can be prevented from falling off.

  In the next terminal bending step, the coil connection portions 3d and 4d of the terminals 3 and 4 are bent in parallel with the imposition portions 3b and 4b and are brought into contact with the other end surface of the terminal mounting portion 2a. This state is shown in the two-dot chain line in FIG. 4 and FIG. In this state, the terminals 3 and 4 are wound around and attached to the corresponding terminal attaching portions 2a, and the bent coil connecting portions 3d and 4d project outward from the ring core 2.

  In a state where the terminal bending process has been performed, since the terminals 3 and 4 are wound around the terminal mounting portion 2 a, these terminals 3 and 4 do not fall off the ring core 2. Therefore, when the terminals 3 and 4 are bonded to the terminal mounting portion 2a as described above in the insertion step, the plating layer on the surface of the terminals 3 and 4 is applied by heat applied to the coil connection portions 3d and 4d in the connection step described later. However, the terminals 3 and 4 do not fall off the ring core 2 even if the adhesive strength against the terminal mounting portion 2a is lowered.

  For this reason, as described above, the terminals 3 and 4 having a plating layer on the entire surface can be used, which is advantageous in terms of cost. Incidentally, in order to cope with the decrease in the adhesive strength due to the heating, the terminals 3 and 4 are formed so that the bonding surface of the terminals 3 and 4 to the ring core 2 is not covered with the plating layer, and the non-plated surface is bonded to the ring core 2. do it. However, in this case, since it is necessary to mask the predetermined surfaces of the terminals 3 and 4 and perform plating, it is disadvantageous in that the cost for that is required.

  In the next drum fitting step, the drum core 7 around which the coil 8 is wound is disposed inside the ring core 2, and one end surface 7 d of the drum core 7 is flush with the imposition portions 3 d and 4 d of the terminals 3 and 4. Like that. In this case, the drum core 7 may be disposed inside the ring core 2 by inserting the drum core 7 into the ring core 2, or conversely, fitting the ring core 2 onto the drum core 7. By this drum fitting process, the flange portions 7b and 7c of the drum core 7 come into contact with the inner peripheral contact portions 3c and 4c of the terminals 3 and 4, and the flange portions 7b and 7c and the arcuate surface 2d on the inner periphery of the ring core 2 are obtained. A magnetic gap G is formed between the two. In this case, since the drum core 7 is sandwiched in the diametrical direction by the inner peripheral contact portions 3c and 4c, the drum core 7 is properly positioned with respect to the ring core 2 by the contact of these two locations, and a magnetic having a predetermined size is obtained. A gap G is formed.

  In the next connecting step, the coil terminal portions 8a and 8b of the coil 8 drawn through the magnetic gap G are individually entangled with the coil connecting portions 3d and 4d of the terminals 3 and 4, for example, by soldering and joining. The terminal portions 8a and 8b and the coil connection portions 3d and 4d are electrically and mechanically connected. 7 and 8 show the connected state, and reference numeral 9 in these figures indicates solder. In this connection, as shown by a two-dot chain line in FIG. 8, a notch 7e that is individually opposed to the terminals 3 and 4 is provided in the flange portion 7b, and a coil terminal portion 8a that is connected to the coil connection portions 3d and 4d therethrough. , 8b may be pulled out. In this case as well, since the flange portion 7c that forms the peripheral portion of the one end surface 7d hits at least the inner peripheral contact portions 3c, 4c, the drum core 7 is properly positioned with respect to the ring core 2.

  The bonding process is performed after the drum fitting process and before the connecting process. In this bonding step, a thermosetting adhesive (not shown) is supplied to the magnetic gap G, and heat is applied to cure the adhesive, thereby bonding the ring core 2 and the drum core 7.

  In the above manufacturing method, the terminals 3 and 4 are wound around and held by the ring core 2 by the insertion process and the terminal bending process, so that the terminals 3 and 4 are not dropped from the ring core 2 in the subsequent processes, and the productivity is good. Further, in the drum fitting process, the drum core 7 around which the coil 8 is wound using the terminals 3 and 4 held by the ring core 2 is positioned with respect to the ring core 2 and a predetermined magnetic force is provided between the cores 2 and 7. A gap G can be formed. In addition, the magnetic gap G is more reliably maintained by the bonding of the ring core 2 and the drum core 7 in the next bonding step. Therefore, as described above, it is possible to manufacture the surface mount type choke coil 1 that can reduce the number of components, is suitable for thinning, and can suppress variation in inductance.

  9 to 14 show a second embodiment of the present invention. Since the second embodiment is basically the same as the first embodiment, the same components are denoted by the same reference numerals as those of the first embodiment, the description thereof is omitted, and matters different from the first embodiment are described below. explain.

  In the second embodiment, the terminal body 5 is used so that the insertion process can be completed only once. As shown in FIG. 9, the terminal body 5 is formed by integrally connecting coil connecting portions 3d and 4d of a pair of terminals 3 and 4 with a bridge portion 6 bent at a right angle thereto. The coil connection portions 3d and 4d have the same width as the inner peripheral contact portions 3c and 4c, and a notch 6a that opens to the side edge at a position serving as a boundary between them, bends the coil connection portions 3d and 4d. It is provided for ease.

  The size of the surface mount type choke coil 1 manufactured as shown in FIG. 14 using this terminal body 5 is 2.0 mm in thickness H and 5.0 mm in length L on one side in the vertical and horizontal directions.

  Next, a method for manufacturing the choke coil 1 will be described. This manufacturing method includes an insertion step, a cutting step, a terminal bending step, a drum fitting step, and a connecting step, and an adhesion step is added if necessary.

  In the insertion process, the terminal body 5 is made to face the ring core 2 as shown in FIG. 9, and the grooves 3e and 4e of the pair of terminals 3 and 4 provided in the terminal body 5 are connected to the terminal mounting portion 2a of the ring core 2. And the terminals 3 and 4 are combined with the ring core 2. In this case, the terminals 3 and 4 may be inserted into the ring core 2, or conversely, the ring core 2 may be inserted into the terminals 3 and 4.

  This combined state is shown in FIG. In this state, the outer peripheral contact portions 3a and 4a of the terminals 3 and 4 are brought into contact with the outer surface 2c of the corresponding terminal mounting portion 2a, and the facing portions 3b and 4b of the terminals 3 and 4 are connected to the corresponding terminal mounting portion 2a. It is attached to one end face. Further, the inner peripheral contact portions 3c and 4c of the terminals 3 and 4 are attached to the inner side surface 2b of the corresponding terminal mounting portion 2a, and the coil connecting portions 3d and 4d of the terminals 3 and 4 and a bridge portion connecting them together. 6 penetrates the ring core 2 and projects upward.

  In this insertion step, it may be added that a thermosetting adhesive is applied to at least a part of the inner surfaces of the grooves 3e and 4e, and heat is applied after the fitting to cure the adhesive. In this case, it is preferable in the point that the terminal body 5 inserted and inserted into the ring core 2 in the subsequent steps can hardly fall off.

  In the next cutting step, the position indicated by the alternate long and short dash line in FIG. 10 is cut with a cutter (not shown) to remove the bridge portion 6 and to make the pair of terminals 3 and 4 independent. FIG. 11 shows a state where the terminals 3 and 4 are independent.

  In the next terminal bending step, the coil connection portions 3d and 4d of the terminals 3 and 4 are bent in parallel with the imposition portions 3b and 4b and are brought into contact with the other end surface of the terminal mounting portion 2a. This state is shown in FIG. In this state, the terminals 3 and 4 are wound around and attached to the corresponding terminal attachment portions 2a.

  In a state where the terminal bending process has been performed, since the terminals 3 and 4 are wound around the terminal mounting portion 2 a, these terminals 3 and 4 do not fall off the ring core 2. Therefore, when the terminals 3 and 4 are bonded to the terminal mounting portion 2a as described above in the insertion step, the surface of the terminals 3 and 4 is heated by the heat applied along with the coil connection portions 3d and 4d in the connection step described later. Even if the plating layer melts and the adhesive strength with respect to the terminal mounting portion 2a may decrease, the terminals 3 and 4 do not fall off the ring core 2. For this reason, as described above, the terminals 3 and 4 having a plating layer on the entire surface can be used, which is advantageous in terms of cost.

  In the next drum fitting step, as shown in FIG. 12, the drum core 7 around which the coil 8 is wound is disposed inside the ring core 2, and the one end surface 7d of the drum core 7 is the imposition portion 3d of the terminals 3 and 4, It should be flush with 4d. In this case, the drum core 7 may be disposed inside the ring core 2 by inserting the drum core 7 into the ring core 2, or conversely, fitting the ring core 2 onto the drum core 7. By this drum fitting process, the flange portions 7b and 7c of the drum core 7 come into contact with the inner peripheral contact portions 3c and 4c of the terminals 3 and 4, and the flange portions 7b and 7c and the arcuate surface 2d on the inner periphery of the ring core 2 are obtained. A magnetic gap G is formed between them (see FIG. 13). In this case, since the drum core 7 is sandwiched in the diametrical direction by the inner peripheral contact portions 3c and 4c, the drum core 7 is properly positioned with respect to the ring core 2 by the contact of these two locations, and a magnetic having a predetermined size is obtained. A gap G is formed.

  In the next connecting step, the coil terminal portions 8a and 8b of the coil 8 drawn through the magnetic gap G are individually entangled with the coil connecting portions 3d and 4d of the terminals 3 and 4, for example, by soldering and joining. The terminal portions 8a and 8b and the coil connection portions 3d and 4d are electrically and mechanically connected. FIG. 14 shows a state where the connection is completed.

  The bonding process is performed after the drum fitting process and before the connecting process. In this bonding step, a thermosetting adhesive (not shown) is supplied to the magnetic gap G, and heat is applied to cure the adhesive, thereby bonding the ring core 2 and the drum core 7.

  In the above manufacturing method, since the terminals 3 and 4 are wound around the ring core 2 by the insertion process and the terminal bending process, the terminals 3 and 4 are not dropped from the ring core 2 in the subsequent processes. Since the terminals 3 and 4 can be inserted into the ring core 2 using the terminal body 5 at a time, the manufacturability is good and more suitable for mass production. Further, in the drum fitting process, the drum core 7 around which the coil 8 is wound using the terminals 3 and 4 held by the ring core 2 is positioned with respect to the ring core 2 and a predetermined magnetic force is provided between the cores 2 and 7. A gap G can be formed. In addition, the magnetic gap G is more reliably maintained by bonding the ring core 2 and the drum core 7 in the next bonding step. Therefore, as described above, it is possible to manufacture the surface mount type choke coil 1 that can reduce the number of components, is suitable for thinning, and can suppress variation in inductance.

Sectional drawing which shows the state before the ring core and pair of terminal of a choke coil which concern on 1st Embodiment of this invention are combined. The top view which shows the ring core in the state of FIG. The perspective view which shows a pair of terminal in the state of FIG. Sectional drawing which shows the state with which the ring core of the choke coil which concerns on 1st Embodiment, and a pair of terminal were combined. The top view which shows the state of FIG. The top view which shows the state in which a pair of terminal was hold | maintained at the ring core of the choke coil which concerns on 1st Embodiment. Sectional drawing which shows the assembly completion state of the choke coil which concerns on 1st Embodiment. The top view which shows the state of FIG. The perspective view which shows the state before the ring core of a choke coil and a pair of terminal which concern on 2nd Embodiment of this invention are combined. The perspective view which shows the state with which the ring core and pair of terminal of the choke coil which concern on 2nd Embodiment were combined. The perspective view which shows the state which obtained the pair of terminal combined with the ring core from the state of FIG. The perspective view which shows the state by which the pair of terminals were hold | maintained at the ring core of the choke coil which concerns on 2nd Embodiment with the drum core wound. The perspective view which shows the state with which the ring core by which the pair of terminal of the choke coil which concerns on 2nd Embodiment was hold | maintained, and the drum core wound by combining were combined. The perspective view which shows the assembly completion state of the choke coil which concerns on 2nd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Choke coil (inductor), 2 ... Ring core, 2a ... Terminal attaching part, 2b ... Inner side surface of a terminal attaching part, 2c ... Outer side surface of a terminal attaching part, 3, 4 ... Terminal, 3a, 4a ... Outer periphery contact part, 3b, 4b ... imposition part, 3c, 4c ... inner peripheral contact part, 3d, 4d ... coil connection part, 3e, 4e ... groove, 5 ... terminal body, 6 ... bridge part, 7 ... drum core, 7a ... winding drum, 7b, 7c ... collar part, 7d ... end face of drum core, 8 ... coil, 8a, 8b ... coil end part, G ... magnetic gap

Claims (5)

Ring core,
The outer peripheral contact portion along the outer surface of the ring core, the imposition portion bent along the one end surface of the ring core from the outer peripheral contact portion, and the inner periphery bent along the inner surface of the ring core from the imposition portion A plurality of terminals comprising a contact portion and a coil connection portion that is bent along the other end surface of the ring core from the inner peripheral contact portion and protrudes outward;
At least one of the flange portions respectively provided at both ends in the axial direction of the winding drum is brought into contact with the inner peripheral contact portion of each terminal, and a magnetic gap is provided between a portion other than the contact portion and the inner periphery of the ring core. A drum core disposed inside the ring core;
A coil having a coil terminal part and wound around the winding drum, and the coil terminal part electrically and mechanically connected to the coil connection part;
A surface-mount inductor comprising:   2. The ring core according to claim 1, wherein the ring core has a plurality of terminal mounting portions, at least an inner surface of the mounting portions is formed as a flat surface, and the terminal is mounted on each of the terminal mounting portions. The surface mount inductor described.   The surface mount inductor according to claim 1 or 2, wherein one end face of the drum core closer to the imposition portion and the imposition portion are connected to each other. An outer peripheral contact portion, an imposition portion bent at a right angle from the outer peripheral contact portion, an inner peripheral contact portion bent at a right angle from the imposition portion so as to be parallel to the outer peripheral contact portion, and the inner periphery A terminal having a coil connection portion that is continuous with the inner peripheral contact portion along a bending direction of the contact portion with respect to the imposition portion, and a groove formed by the outer peripheral contact portion, the imposition portion, and the inner peripheral contact portion; An insertion step of fitting the ring core and combining with the ring core;
A terminal bending step of bending the coil connection portion in parallel with the imposition portion and holding the terminal on the ring core;
A drum core around which a coil is wound is disposed inside the ring core, and the flange portion of the drum core is brought into contact with the inner peripheral contact portion, and between the portion other than the contact portion and the inner periphery of the ring core A drum fitting process for providing a magnetic gap;
A connection step of electrically and mechanically connecting a coil terminal portion of the coil to the coil connection portion;
A method for manufacturing a surface-mount inductor comprising: A pair of terminals includes a terminal body integrated integrally with a bridge portion, and the pair of terminals includes an outer peripheral contact portion, an imposition portion bent at a right angle from the outer peripheral contact portion, and the imposition portion from the imposition portion An inner peripheral contact portion that is bent at a right angle so as to be parallel to the outer peripheral contact portion, and a coil connecting portion that is continuous with the inner peripheral contact portion along the bending direction of the inner peripheral contact portion with respect to the imposition portion. An insertion step of combining the ring core and the terminal body by fitting the ring core with the groove formed by the outer peripheral contact portion, the imposition portion, and the inner peripheral contact portion;
A cutting step of removing the bridge portion by cutting the bridge portion side portion of the coil connection portion;
A terminal bending step of bending the coil connection portion in parallel with the imposition portion and holding the terminal on the ring core;
The drum core around which the coil is wound is inserted inside the ring core, and the flange portion of the drum core is brought into contact with the inner peripheral contact portion, and between the portion other than the contact portion and the inner periphery of the ring core A drum fitting process for providing a magnetic gap;
A connection step of electrically and mechanically connecting a coil terminal portion of the coil to the coil connection portion;
A method for manufacturing a surface-mount inductor comprising:

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