CN1655298B - Surface mount type coil part and manufacturing method thereof - Google Patents

Abstract

The present invention provides a surface mount type coil component capable of suppressing variations in coil characteristics for each product and improving the bonding strength between a drum core and a metal plate terminal with a simple structure, and a method for manufacturing the same. The surface-mounted coil part (1) mainly includes: a drum-shaped core (5) with a cylindrical body (3) and a pair of flanges (2a, 2b) arranged at both ends of the body (3); Coil (4) on (3); Surround the exterior core (6) of drum type core (5) around the shaft; And the flange ( 2b) A pair of metal plate terminals (7a, 7b) bonded for connection to the mounting surface. Embossing is performed on the surfaces (S1, S2) bonded to the flanges (2b) of the metal plate terminals (7a, 7b), respectively. In addition, a granular filler (13) is contained in the adhesive (12).

Description

Surface mount type coil part and manufacturing method thereof

technical field

The present invention relates to a surface mount type coil component mounted on a circuit board of an electronic device and a manufacturing method thereof.

Background technique

In general, a surface-mounted coil component has a pair of metal plate terminals obtained from a lead frame bonded to the bottom surface of a drum-shaped core around which the coil is wound, for connecting the mounting surface. A solder plating layer is formed on the metal plate terminal to improve the solderability of the coil and the circuit board. However, when dipping into the solder layer when connecting the coil and the metal plate terminal, or passing through the reflow furnace when the completed surface mount coil part is mounted on the circuit board, the heat applied at this time melts or dissolves the plating layer, Decreases the bond strength between the drum core and the sheet metal terminal. Therefore, when shock or vibration or the like is applied to the finished surface-mounted coil part, the drum core deviates from the metal plate terminal and falls off. In recent years, in electronic devices such as mobile phones, digital cameras, and hard disk devices, surface-mounted coil components with high reliability against shocks and vibrations such as dropping are required.

In order to solve this problem, the following Patent Document 1 proposes a method of providing a recessed portion on the bottom of a drum-shaped core, inserting a fixing portion and claw formed on a metal plate terminal into the recessed portion, and then fixing it with an adhesive.

Patent Document 1: Japanese Unexamined Patent Publication No. 9-148148

However, with the method described in the aforementioned Patent Document 1, the method is troublesome due to its complicated structure. In the conventional surface-mounted coil components, the drum-shaped core is generally bonded to the lead frame (metal plate terminal) with an adhesive at the time of manufacture. Because of this, the length in the height direction is greatly affected by the thickness of the adhesive, and errors (tolerances) are likely to occur between products, and uniform surface mount coil parts may not be obtained. In this way, the length and the number of turns of the coil vary among products, and it is impossible to maintain constant coil characteristics such as DC resistance value (Rdc) for each product.

Contents of the invention

The present invention has been made in consideration of the problems of the prior art described above, and its object is to provide a coil that can suppress the deviation of the coil characteristics of each product and can improve the adhesion between the drum core and the metal plate terminal with a simple structure. A surface-mounted coil component with high bonding strength and a manufacturing method thereof.

A surface-mounted coil part of the present invention is characterized in that it comprises: a drum-shaped core having a columnar body and a pair of flanges provided at both ends of the body; a coil wound on the body; A pair of metal plate terminals for connecting the mounting surface bonded to one of the flanges is embossed on the surface bonded to the flange of the metal plate terminal, and the adhesive contains a granular filler.

According to the present invention, since the bonding surface to the flange of the metal plate terminal is embossed, unevenness is formed on the surface of the bonding surface. In this way, the bonding strength between the metal plate terminal and the flange bonded by the adhesive is improved, and therefore, the bonding strength between the metal plate terminal and the drum core is improved. In addition, since the adhesive contains the granular filler, the distance between the metal plate terminal and the flange after bonding is maintained at a length substantially equal to the particle diameter of the granular filler. In this way, since errors among products can be reduced, variations in coil characteristics for each product can be suppressed.

In this case, it is preferable that the number of the granular filler per unit area is greater than the number of recesses formed on the bonding surface with the flange of the metal plate terminal by the embossing. In this way, since all of the granular filler enters the concave portion formed by embossing, it is possible to prevent the gap between the bonded metal plate terminal and the flange from being smaller than other products, so that the gap between products can be reduced more reliably. error.

In addition, a level difference is formed in at least a part of the peripheral edge of the bonding surface with the metal plate terminal of the flange. In this case, when the metal plate terminal and the flange are pressed with the adhesive, the remaining portion of the adhesive is pushed out toward the edge of the flange and accumulated in the stepped portion provided on the peripheral edge of the flange. Therefore, a portion where the thickness of the adhesive layer is larger than other portions is formed near the peripheral edge portion of the flange. The adhesive strength can be further improved. Here, the term "step difference" also includes a case where the cross section is arcuate.

Preferably, the peripheral edge of the surface bonded to the metal plate terminal of the flange is chamfered. Thus, when the metal plate terminal and the flange are pressed with the adhesive, the remaining portion of the adhesive is pushed out toward the edge of the flange and accumulated in the area sandwiched between the chamfered portion and the metal plate terminal. Therefore, a portion where the thickness of the adhesive layer is larger than other portions is formed near the peripheral edge of the flange. The adhesive strength can be further improved.

The adhesive is preferably applied in the form of a ring on the surface to be bonded to the sheet metal terminal of the flange. In this way, even when the flange rotates in the circumferential direction on the metal plate terminal, it is possible to prevent the portion where the adhesive is not applied on the metal terminal, and to minimize the amount of adhesive disposed between the flange and the metal plate terminal. Stablize. Therefore, the adhesive strength of each product can be maintained substantially constant, the quality can be maintained, and it is suitable for mass production. In addition, by applying the adhesive in a ring shape, it is possible to prevent the central part of the adhesive layer from being dented in the case of full-surface application, so that there is no variation in the amount of adhesive applied, and it can be The state where the adhesive is applied to the flange with a substantially uniform thickness.

In addition, it is preferable that a part of the edge of the metal plate terminal is bent toward the mounting surface. Thus, by using the bent edge, the height from the mounting surface of the drum-shaped core can be specified with high precision, and at the same time, both ends of the coil can be placed on the back side of the surface bonded to the flange of the metal plate terminal.

The method for manufacturing a surface-mounted coil part of the present invention is characterized in that the surface-mounted coil part comprises: a drum-shaped core having a columnar body and a pair of flanges provided at both ends of the body; a coil; and a pair of metal plate terminals bonded to one of the flanges for connecting a mounting surface, the manufacturing method comprising: (a) embossing the bonding surface of the flange with the metal plate terminal Steps; (b) a step of preparing an adhesive containing a granular filler; (c) a step of bonding the flange and the metal plate terminal with the adhesive.

According to the present invention, by performing embossing on the surface to be bonded to the flange of the metal plate terminal, the bonding strength between the metal plate terminal and the flange bonded by an adhesive can be improved. By using an adhesive containing a granular filler, the gap between the bonded metal plate terminal and the flange can be maintained at a length substantially equal to the particle diameter of the granular filler. Therefore, it is possible to realize a surface-mounted coil component that reduces variations between products and suppresses variations in coil characteristics for each product.

In this case, it is preferable that the number of particulate fillers per unit area is greater than the number of recesses formed on the bonding surface with the flange of the metal plate terminal by embossing. In this way, since all of the granular filler enters the recesses formed by embossing, the gap between the bonded metal plate terminal and the flange can be prevented from being narrower than other products, so that the error between products can be more reliably reduced.

In addition, it is preferable that a step is formed on at least a part of the peripheral edge of the bonding surface with the metal plate terminal of the flange. When the metal plate terminal and the flange are pressed by bonding, the remaining portion of the adhesive is pushed out toward the edge of the flange and accumulated in the step portion provided on the peripheral edge of the flange. Therefore, since the thickness of the adhesive layer is formed in a portion near the peripheral edge of the flange that is larger than other portions, the adhesive strength can be further improved.

Preferably, the peripheral edge of the bonding surface of the metal plate terminal to the flange is chamfered. Thus, when the metal plate terminal and the flange are pressed by bonding, the remaining portion of the adhesive is pushed out toward the edge of the flange and accumulated in the area sandwiched between the chamfered portion and the metal plate terminal. Therefore, since the thickness of the adhesive layer is formed in a portion near the peripheral edge of the flange that is larger than other portions, the adhesive strength can be further improved.

Preferably, the adhesive is applied in a ring shape on the bonding surface with the metal plate terminal of the flange. In this way, even if the flange is rotated in the peripheral direction on the metal plate terminal, it is possible to prevent the portion not coated with adhesive from being located on the metal terminal, and the amount of adhesive disposed between the flange and the metal plate terminal can be minimized. Stablize. Therefore, the adhesive strength of each product can be maintained substantially constant, the quality can be maintained, and it is suitable for mass production. In addition, by applying the adhesive in a ring shape, it is possible to prevent the central part of the adhesive layer from being sunken in the case of full-surface application, so that the flange can be applied with a substantially uniform thickness. state of the adhesive.

In addition, it is preferable to bend a part of the edge of the metal plate terminal on the mounting surface side. In this way, the height from the mounting surface of the drum-shaped core can be specified with high precision by using the bent edge, and at the same time, both ends of the coil can be accommodated on the back side of the surface to which the flange of the metal plate terminal is bonded.

According to the present invention, in the surface-mounted coil component and its manufacturing method, embossing is performed on the surface bonded to the flange of the drum-shaped core in the metal plate terminal, and at the same time, since the adhesive containing the granular filler is used Adhesive is used to bond the metal plate terminal and the above-mentioned flange, so the bonding strength between the drum core and the metal plate terminal can be improved with a simple structure, and the variation of the coil characteristics of each product can be suppressed.

Description of drawings

FIG. 1 is a perspective view showing a state in which an exterior core of a surface-mounted coil component of the present invention is removed;

Fig. 2 is a perspective view showing a state in which an outer core of the surface-mounted coil part shown in Fig. 1 is removed;

Fig. 3 is a perspective plan view showing a bonded state of a drum-type core and a metal plate terminal;

Fig. 4 is the sectional view of line IV-IV of Fig. 3;

Fig. 5 (a) is the plane view of recess, and Fig. 5 (b) is the sectional view along the V-V line of recess;

FIG. 6 is an enlarged view showing area A in FIG. 4;

FIG. 7 is a diagram showing the manufacturing process of the surface-mounted coil component of the present embodiment;

FIG. 8 is a diagram showing the manufacturing process of the surface mount type coil component of the present embodiment continuing from FIG. 7;

FIG. 9 is a diagram showing the manufacturing process of the surface mount type coil component of the present embodiment following FIG. 8;

FIG. 10 is a view showing the manufacturing process of the surface-mounted coil component of the present embodiment continuing from FIG. 9;

Fig. 11 is a view showing the surface of the flange to which the adhesive is applied;

Fig. 12 is a diagram showing a process of applying an adhesive to a flange;

Fig. 13 is the figure of comparative example 1 of the present invention;

Fig. 14 is the figure of comparative example 1 of the present invention;

Fig. 15 is the figure of embodiment 1 of the present invention;

Fig. 16 is the figure of embodiment 1 of the present invention;

Fig. 17 is the figure of embodiment 2 of the present invention;

Fig. 18 is the figure of embodiment 2 of the present invention;

Fig. 19 is the figure of embodiment 3 of the present invention;

Fig. 20 is the figure of embodiment 3 of the present invention;

Explanation of symbols: 1-surface-mounted coil part; 2a, 2b-flange; 3-body; 4-coil; 5-drum core; 6-outer core; 7a, 7b-metal plate terminal; 10-recess ;11-step difference; 12-adhesive; 13-granular filler; 17a, 17b-edge; 20-lead frame; 20a, 20b-lead terminal (metal plate terminal); 31-flange; 33-metal plate terminal; 41-flange; 42-adhesive; 43-metal plate terminal; 44-step difference; 51-flange; 52-adhesive; 53-metal plate terminal; 53-convex edge; 55-recess; 65-recess; 66-step difference.

Detailed ways

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the description of the drawings, the same or corresponding parts are denoted by the same symbols, and repeated explanations are omitted.

FIG. 1 is a perspective view showing a surface mount type coil component 1 according to this embodiment. FIG. 2 is a perspective view showing a state in which the outer core 6 of the surface mount type coil component 1 shown in FIG. 1 is removed. The surface-mount coil component 1 is surface-mounted on a printed wiring board or the like by reflow soldering or the like, and thus can be used in electronic equipment such as mobile phones, digital cameras, and hard disk devices. It can also be used as an SMD (Surface Mount Device) coil part for a power supply, a choke coil part for a DCDC converter, etc.

The surface-mounted coil part 1 mainly has: a columnar body 3 (see Fig. 3, Fig. 4), a drum-shaped core 5 with a pair of flanges 2a, 2b arranged at both ends of the body 3, wound on the body 3 The coil 4 on the top, the outer core 6 arranged around the drum core 5 around the shaft, a pair of metal plate terminals 7a bonded to the flange 2b of the drum core 5 for connecting the mounting surface, 7b.

The drum-shaped core 5 is made of Ni-Cu-Zn-based magnetic material, for example, it consists of a cylindrical body 3 wound with a coil 4, and a pair of disc-shaped discs arranged at both ends of the body 3 in the axial direction. Flanges 2a, 2b form. The axial center of the cylindrical body 3 coincides with the axial centers of the disk-shaped flanges 2a, 2b.

The coil 4 is a polyurethane coating for insulating the copper wire, and the polyurethane coating can be removed at both ends in order to conduct conduction with the metal plate terminals 7a and 7b. Both ends of the coil 4 are arranged on the back side of the surfaces S ₁ and S ₂ bonded to the flanges 2 b of the metal plate terminals 7 a and 7 b. In this embodiment, the coil 4 is wound on the main body 3 in one direction, but it may be wound on the main body 3 by a so-called cross method. In addition, the coil 4 can be a flat square shape (rectangular cross-section), or a round wire shape.

Like the drum core 5 , the sheath core 6 can be made of, for example, a Ni-Cu-Zn magnetic material, and is disposed between the drum core 5 through the core gap 8 . In order to make the core gap 8 approximately constant along the circumferential direction, the inner wall surface of the outer core 6 corresponds to the outer peripheral surface of the drum-shaped core 5 and constitutes a concave curved surface. The core gap 8, which is the gap between the drum core 5 and the sheath core 6, affects the coil characteristics.

The metal plate terminals 7a and 7b are made of, for example, a copper alloy such as phosphor bronze, and can be obtained by cutting a lead frame 20 described later. The pair of metal plate terminals 7a and 7b have a long shape, and are adhered to the flange 2b of the drum core 5 in a substantially parallel state by an adhesive 12 described later. In addition, the edges 17a, 17a, and 17b, 17b of the metal plate terminals 7a, 7b are bent on the mounting surface side facing each other. The extending directions of the edges 17a, 17a and 17b, 17b (Y direction in the figure) are substantially parallel, so that the surface-mounted coil component 1 can be stably mounted on the mounting surface. In this embodiment, a pair of edges 17a, 17a and 17b, 17b at both ends of the metal plate terminals 7a, 7b are bent so that the cross section of the metal plate terminals 7a, 7b is roughly U-shaped, while the metal plate terminals 7a, One (one-sided) edge 17a, 17b of 7b can also be bent towards the mounting surface.

Fig. 3 is a perspective plan view showing a state in which the drum core 5 and the metal plate terminals 7a, 7b are bonded. FIG. 4 is a sectional view taken along line IV-IV of FIG. 3 . In Fig. 3 and Fig. 4, the coil 4 is omitted in consideration of easy visibility of the drum-shaped core 5 and the metal plate ends 7a, 7b.

As shown in FIG. 3 , a plurality of recesses 10 are formed at a predetermined arrangement pitch on the surfaces S ₁ , S ₂ bonded to the flanges 2b of the metal plate terminals 7a, 7b.

5( a ) is a plan view of the concave portion 10 , and FIG. 5( b ) is a cross-sectional view of the concave portion 10 along line V-V. By performing embossing on the surface of the metal plate terminals 7a, 7b, the recessed part 10 is made into the shape of a quadrangular pyramid as shown in FIG. 5, for example. In this case, the concave portion 10 is formed as a square with sides of 0.04 mm, a depth of about 0.02 mm, and an arrangement pitch of 0.2 mm. And the density (embossing density) with respect to the surface of metal plate terminal 7a, 7b is 3-5%. In addition, the shape of the concave portion 10 is not limited to a quadrangular pyramid shape, and other pyramidal shapes such as a cone or a triangular pyramid, a substantially hemispherical shape, a rectangular shape, or the like may also be used.

Referring to Fig. 3 and Fig. 4 again, a step difference 11 is provided on the entire periphery of the peripheral edge of the surface _S3 of the flange 2b which is in contact with the metal plate terminals 7a, 7b. The step difference 11 has a height of 0.05 mm and a width of about 0.10 mm. This step 11 provides a region between the flange 2b and the metal plate terminals 7a, 7b that is farther away from the metal plate terminals 7a, 7b than other locations. 3 and 4, in this embodiment, a step 11 is also provided on the peripheral edge of the surface _S4 of the flange 2a. In this way, when the drum core 5 is bonded to the metal plate terminals 7a, 7b, in the case where either flange is bonded to the metal plate terminals 7a, 7b, the distance ratio to the metal plate terminals 7a, 7b can also be set. other large areas.

FIG. 6 is an enlarged view showing area A in FIG. 4 . The flange 2b is bonded to the metal plate terminal 7a ( 7b ) with an adhesive 12 . At this time, the adhesive 12 is also placed on the area between the step 11 and the metal plate terminals 7a, 7b (see hatched portion C in FIG. 3 ). The adhesive 12 has an epoxy resin as a main component, and further contains a granular filler 13 such as calcium carbonate (CaCO ₃ ) or glass beads. In addition, it also contains hardening agents such as dicyandiamide.

The granular filler 13 has a particle diameter of, for example, about 20 μm, and is contained in the adhesive 12 such that the number per unit area is greater than that of the recesses 10 formed on the metal plate terminals 7a, 7b. In this way, not all of the granular filler 13 is embedded in the concave portion 10, so that the distance between the flange 2b and the metal plate terminals 7a, 7b is always maintained at the particle diameter of the granular filler 13. Therefore, errors among products can be prevented.

Next, a method of manufacturing the surface mount type coil component 1 according to this embodiment will be described with reference to FIGS. 7 to 12 .

First, a lead frame 20 in which a pair of lead terminals 20a and 20b are provided integrally is prepared. The lead terminals 20a, 20b correspond to the above-mentioned metal plate terminals 7a, 7b. The lead frame 20 is made of copper alloy such as phosphor bronze.

The lead terminals 20a, 20b of the lead frame 20 are bent to form a substantially U-shaped cross section in advance, and the edges 17a, 17a and 17b, 17b are respectively bent toward the mounting surface. In addition, the surface to be bonded to the flange 2b of the lead terminals 20a, 20b is embossed in advance to form the plurality of recesses 10 described above.

As shown in FIG. 7(a), one flange 2b of the drum-shaped core 5 is bonded to the surface opposite to the mounting surface of the lead terminals 20a, 20b with an adhesive 12. At this time, as shown in FIG. 11, the adhesive 12 (hatched portion) is coated on the flange 2b of the drum core 5 in a ring shape. The hardening condition of the adhesive is at a temperature of 150-160° C. for 30-60 minutes. The adhesive 12 contains a granular filler 13 such as calcium carbonate (CaCO ₃ ) in advance together with a curing agent. The granular filler 13 is desired to have an average particle diameter of 15-25 μm. When the concave portion 10 is a square of 0.04 mm on each side, the depth is about 0.02 mm, and the arrangement pitch is 0.2 mm, the average particle diameter is 20 μm. The content occupied in 12 is, for example, 47% by weight.

The adhesive 12 is stretched in the direction of the arrow in FIG. 11 by pressing when the flange 2b is adhered to the lead terminals 20a, 20b. At this time, as shown in FIG. 6, a part of the adhesive 12 pushed out to the edge of the flange 2b is accumulated in the step 11 formed on the peripheral edge. Thus, the thickness of the adhesive layer increases, and the bonding strength between the lead terminals 20a, 20b and the flange 2b increases several times.

As shown in FIG. 12( a ), the adhesive 12 is applied to the flange 2b by using a plate (Tetron) 24 equipped with a ring-shaped mesh 23 . The opening size of the mesh 23 is, for example, about 80 μm. The drum-shaped core 5 is placed under the plate making 24 , and the adhesive 12 is placed on a position other than the mesh 23 of the plate making 24 . The adhesive 12 is slid on the slide table 25 to pass through the mesh 23 . Then, as shown in FIG. 12(a), the adhesive 12 falls downward through the mesh 23, and is coated on the surface _S3 of the flange 2b in a ring shape. At this time, the layer thickness of the adhesive 12 corresponds to the thickness of the plate 24 and is about 25 μm.

In this way, by applying the adhesive 12 in a ring shape, even if the drum core 5 is rotated in the circumferential direction of the flange 2b due to vibration or shaking during transportation, it is possible to prevent the failure of the adhesive 12 to be applied. The situation occurs partially on the sheet metal terminals 7a, 7b. Due to this, the amount of the adhesive 12 disposed between the flange 2b and the metal plate terminals 7a, 7b can be stabilized. In addition, when the surface _S3 of the flange 2b is completely coated with a mesh such as a circle, as shown in FIG. . By using the annular mesh 23 , as shown in FIG. 12( d ), the layer thickness is substantially uniform, and variation in the amount of application of the adhesive 12 can be suppressed.

After the drum-shaped cores 5 are bonded to the lead terminals 20a and 20b, as shown in FIG. Divided into two parts. FIG. 7(c) shows a state where the lead frame 20 is divided into two. 7(b), (c) show the state seen from the side opposite to the side to which the drum-shaped core 5 is adhered (the lower side in FIG. 7(a)).

Next, as shown in Figure 8 (a), after the coil 4 is wound on the main body 3 of the drum-shaped core 5 by the winding machine 21, as shown in Figure 8 (b), the pair of coils 4 are The ends 4a, 4b are led back to the rear side of the respective lead terminals 20a, 20b and cut off.

Next, as shown in Fig. 8 (c), carry out lead-free solder 22 to immerse (soak) the backside side (the opposite side with drum-shaped core 5) welding of lead terminal 20a, 20b, lead terminal 20a respectively , 20b and the ends 4a, 4b of the coil 4 are connected (electrically, mechanically).

Next, as shown in FIG. 9( a ), V-cutting is performed to form a V-shaped groove on the base end portions of the lead terminals 20 a and 20 b (at the boundary portion between the presence and absence of the lead-free solder 22 ). Also as shown in FIG. 9( b ), a plurality of exterior cores 6 are arranged at the same arrangement pitch as the drum cores 5 . Adhesive 23 is applied to the four corners of each exterior core 6 . The adhesive 23 is used for bonding the lead terminals 20a, 20b, but the same adhesive as the above-mentioned adhesive 12 can be used in order to reduce errors such as height differences between products.

In addition, as shown in FIG. 9( c), after assembling the outer cores 6 arranged so that they are respectively installed on the drum core 5, the adhesive 23 is cured, and the outer cores 6 and the lead terminals 20a, 20b are bonding. Then, after ferrite powder is coated on the upper surfaces of the exterior core 6 and the drum core 5, the inductance value, polarity indication, etc. are printed on the surface (see FIG. 10(a)). Also, as shown in FIG. 10(b), by cutting the lead terminals 20a, 20b at the V-cut processing portion, a plurality of surface-mounted coil components 1 can be obtained as shown in FIG. 1 .

In the above-mentioned surface mount type coil component 1 of the present embodiment, a concave-convex pattern by embossing is formed on the surface _S3 bonded to the flange 2b of the metal plate terminals 7a, 7b. Because of this, the bonding strength when the metal plate terminals 7a, 7b and the flange 2b are bonded can be improved by the adhesive agent 12 . In addition, since the adhesive 12 contains the granular filler 13 , the gap between the metal plate terminals 7 a , 7 b and the flange 2 b after bonding is maintained at the particle diameter of the granular filler 13 . In this way, since errors among products are reduced, variations in coil characteristics for each product can be suppressed. The granular filler 13 also has a function of adjusting the viscosity of the adhesive 12 .

In addition, a pair of edges 17a, 17a and 17b, 17b located at both ends of the metal plate terminals 7a, 7b are respectively bent, so that the metal plate terminals 7a, 7b have a substantially U-shaped cross section. Because of this, the height of the drum-shaped core 5 from the mounting surface can be maintained with high precision, and at the same time, the ends 4a, 4b of the coil 4 can be accommodated on the back of the metal plate terminals 7a, 7b by using an easy process and a simple structure. side.

In addition, according to the surface mount type coil component 1 of the present invention, when the ends 4a, 4b of the coil 4 are brought back to the back side of the metal plate terminals 7a, 7b, the length of the coil 4 can be controlled at a constant level, and the coil 4 can be stably controlled. Manage its length. As described above, by including the granular filler 13 in the adhesive 12, the distance between the bonded metal plate terminals 7a, 7b and the flange 2b, that is, the distance between the drum core 5 and the mounting surface can be kept constant. . In the coil 4 of the present invention, almost the same length (for example, uniformly 10.028 mm) is used for any surface mount type coil component 1 formed on the lead frame 20 . Therefore, by controlling the length of the coil 4 to be constant and performing length management stably, the resistance components of the respective surface mount type coil components 1 can be made almost all the same. Therefore, it is possible to realize the surface mount type coil component 1 in which the error (tolerance) between products is very small.

As mentioned above, although the preferred embodiment of this invention was described in detail, this invention is not limited to the said embodiment. For example, in the above-mentioned embodiment, the step 11 is formed on the entire periphery of the peripheral edge of the surface S3 that is in contact with the metal plate terminals 7a, 7b of the flange _2b , and the step is formed on a part of the peripheral edge of the surface _S3 . 11 is also available.

In addition, a structure in which the peripheral edge of the surface _S3 is chamfered may also be used. In this way, as in the case of forming the step difference 11, when the metal plate terminals 7a, 7b and the flange 2b are pressed against each other by the adhesive 12, the remaining part of the adhesive 12 is pushed out toward the edge of the flange 2b and accumulated on the edge of the flange 2b. In the area sandwiched between the chamfered portion and the sheet metal terminals 7a, 7b. Since the thickness of the adhesive layer is formed in a portion that is thicker than other parts near the peripheral edge of the flange 2b, the bonding strength between the metal plate terminals 7a, 7b and the flange 2b can be further improved.

(Example 1)

Hereinafter, referring to FIGS. 13 to 20 , the content of the surface mount type coil component of the present invention will be described in detail with examples and comparative examples, but the present invention is not limited to these examples. The bonding strength shown below is obtained by fixing the flange not bonded to the metal plate terminal to the base, and in this state, applying a tensile load in the direction of separation from the base to the flange bonded to the metal plate terminal On the end, it is determined by measuring the load when the metal plate terminal and the flange are peeled off.

The various dimensions of the surface-mounted coil parts of the examples and comparative examples shown below are as follows: in the exterior core, the longitudinal length is 4.00 mm, the transverse length is 4.00 mm, and the height (thickness) is 1.80 mm; In the core, the disc-shaped flange has an inner diameter of 2.80mm and a thickness of 0.35mm, and the cylindrical body has an inner diameter of 1.50mm and an axial length of 1.50mm; in the metal plate terminal, the thickness is 0.30mm. In addition, the adhesive contains a granular filler, which is easy to see and is omitted from the drawing.

(comparative example 1)

13 is a partially enlarged view showing a part of the surface-mount coil component of Comparative Example 1, and FIG. 14 is a diagram showing the relationship between adhesive thickness and adhesive strength of the surface-mount coil component shown in FIG. 13 .

In this comparative example 1, using a surface mount type coil component without embossing on the bonding surface of the metal plate terminal 33 and the flange 31 shown in FIG _. (μm) the change of the adhesive strength (gf).

The results of the measurement are shown in Figure 14. As the layer thickness _L1 of the adhesive increases, the bonding strength increases, but when the layer thickness _L1 of the adhesive exceeds 60 μm, the increase decreases, towards about 300 (gf ) of the bond strength changes. Therefore, it is most appropriate to set the layer thickness _L1 of the adhesive to 60 to 80 μm.

(Example 1)

15 is a partially enlarged view showing a part of the surface-mount coil component of Example 1, and FIG. 16 is a diagram showing the relationship between the level difference and the adhesive strength of the surface-mount coil component shown in FIG. 15 .

In Example 1, using a surface mount type coil component having a step 44 formed on the circumference of the flange 41 shown in FIG. 15, the adhesive strength (gf) when the step width _D1 (mm) was changed was measured The change. Also in the first embodiment, embossing is not performed on the bonding surface between the metal plate terminal 43 and the flange 41 . In addition, the layer thickness L ₂ of the adhesive 42 is 20 μm.

The measurement results are shown in Figure 16. As the step width _D1 increases, the adhesive strength increases, but when the step width _D1 is about 0.10-0.15 mm, the increase decreases, and it reaches about 300-320 (gf ) of the bond strength changes.

(Example 2)

17 is a partially enlarged view showing a part of the surface-mounted coil component of Example 2, and FIG. 18 is a graph showing the embossing density (with respect to the concave portion on the surface of the metal plate terminal surface) in the surface-mounted coil component shown in FIG. 17. 55 density) and the relationship between the bond strength.

As shown in FIG. 17 , in Example 2, using a surface-mounted coil component that is embossed (formed with a recess 55 ) on the bonding surface of the metal plate terminal 53 and the flange 51 , the effect of changing the embossing process was measured. Changes in adhesive strength (gf) at density (%). In addition, in the second embodiment, no step is formed on the circumference of the flange 51 . In addition, the layer thickness _L3 of the adhesive 52 is 20 μm.

The measurement results are shown in Fig. 18. As the embossing density (%) increases, the adhesive strength increases. When the embossing processing density (%) is 4%, the bonding strength is close to 300 (gf), when it is below 6%, the bonding strength exceeds 300 (gf), and when it is 8%, it can reach 310 (gf).

(Example 3)

Fig. 19 is a partially enlarged view showing a part of a surface-mounted coil component formed with a step 66 and a recess 65 caused by embossing, and Fig. 20 is a surface-mounted coil component in which neither the step nor the recess 65 formed by embossing is formed. A graph comparing the adhesive strength of a coil component, a surface-mount coil component having a step width of 0.15 mm without forming an embossed recess, and a surface-mount coil component shown in FIG. 19 .

As shown in FIG. 20, in the surface-mounted coil part in which both the step 66 and the concave part 65 by embossing were formed, the adhesive strength was about 80 (gf) higher than that of the part in which only the step was formed, and in and without In the case of comparing parts with both the step difference and the concave part formed by embossing, the bonding strength can be more than doubled.

Claims (12)

1. A surface-mounted coil part, characterized in that it has: a drum-shaped core having a cylindrical body and a pair of flanges at both ends of the body; a coil wound on the body; a pair of sheet metal terminals bonded by adhesive to one of said flanges for connection to a mounting surface, Embossing is performed on the bonding surface of the metal plate terminal to the flange, The adhesive contains granular fillers, The number of particles per unit area of the granular filler is greater than the number of recesses formed on the bonding surface of the metal plate terminal with the flange by the embossing. 2. The surface mount type coil component according to claim 1, wherein a step is formed on at least a part of the peripheral edge of the bonding surface of the flange with the metal plate terminal. 3. The surface mount type coil component according to claim 1, wherein the peripheral edge of the bonding surface of the flange and the metal plate terminal is chamfered. 4. The surface-mounted coil component according to any one of claims 1 to 3, wherein the adhesive is applied in a ring shape to the bonding between the flange and the metal plate terminal. face. 5. The surface mount type coil component according to any one of claims 1 to 3, wherein a part of the edge of the metal plate terminal is bent on the mounting surface side. 6. The surface mount type coil component according to claim 4, wherein a part of the edge of the metal plate terminal is bent on the mounting surface side. 7. A method of manufacturing a surface-mounted coil part, characterized in that the surface-mounted coil part has: a drum-shaped core having a cylindrical body and a pair of flanges at both ends of the body; a coil wound on the body; a pair of sheet metal terminals bonded to one of said flanges for connection to a mounting surface, The manufacturing method comprises: (a) a step of embossing the bonding surface of the metal plate terminal to the flange; (b) the process of preparing an adhesive containing a granular filler; (c) a step of bonding the flange and the metal plate terminal with the adhesive, The number of the granular filler per unit area is greater than the number of recesses formed on the bonding surface of the metal plate terminal with the flange by the embossing. 8. The method of manufacturing a surface-mounted coil component according to claim 7, wherein a step is formed in at least a part of the peripheral edge of the bonding surface of the flange with the metal plate terminal. 9. The method of manufacturing a surface-mounted coil component according to claim 7, wherein a peripheral edge of a bonding surface of the flange to the metal plate terminal is chamfered. 10. The method for manufacturing a surface-mounted coil component according to any one of claims 7 to 9, wherein the adhesive is applied in a ring shape between the flange and the metal plate. bonding surface of the terminal. 11. The method of manufacturing a surface mount type coil component according to any one of claims 7 to 9, further comprising a step of bending a part of the edge of the metal plate terminal on the mounting surface side. 12. The method of manufacturing a surface mount type coil component according to claim 10, further comprising a step of bending a part of the edge of the metal plate terminal on the mounting surface side.

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