Coil component

The present invention relates to a coil component, and more particularly, to a coil component having a drum core.

Conventionally, a coil component having a core with a coil winding portion and flanges on both ends of the coil winding portion and a winding wound over the coil winding portion have been used in an electronic device for noise suppression. When mounting the coil component on the circuit board, an end face of one flange is ordinarily used as a mounting surface for stability considerations and the like.

Since electrodes are formed on the circuit board, terminal electrodes are often disposed in the mounting surface of the coil component to be conductively connected to the electrodes on the circuit board. Here, and the winding is connected to the terminal electrodes, as described in Japanese Patent Application publication No. 2005-210055.

However, the requirements for high-density mounting in electronic devices have become more stringent in recent years with the increasing high performance of mobile telephones and the like. Therefore, efforts are being made to reduce the volume and height of coil component, as well as the gap between adjacent coil components.

However, when the winding is connected to terminal electrodes at the mounting surface, the height of the coil component is increased by the height or diameter of the winding. The JP publication also describes forming a depression in the mounting surface and connecting the winding within this depression. However, since the shape of the core component is more complex in this case, the core component is more difficult to manufacture, and the strength of the core component may be lowered.

Further, because the mounting portion of the coil component cannot be seen when mounting the coil component on the circuit board, some coil components are constructed with the electrodes on the peripheral surface of the flange. However, this sometimes causes short-circuiting between electrode parts when adjacent coil components are placed close together. As a result, adjacent coil components must be separated a certain distance in this case, which is problematic when striving for high-density mounting.

It is therefore an object of the present invention to provide a coil component having a low profile and being conducive to high-density mounting.

This and other object of the present invention will be attained by a coil component including a core, a winding, and terminal electrodes. The core includes a coil winding portion having one axial end and another axial end, a first flange disposed on the one axial end and defining a first end face of the core, and a second flange disposed on the another axial end and defining a second end face of the core. The first flange has a bottom surface constituting the first end face and a peripheral surface extending toward the second end face from a peripheral edge of the bottom surface. The bottom surface has a first side and a second side opposing the first side, a first omitted side at a first end of the first side, and a second omitted side at one of a first end and a second end of the second side. The first omitted side is configured as if a first corner located on a first end of a first specific side (corresponding to the first side) of an imaginary quadrangle is chamfered or cut. The second omitted side is configured as if a second corner located on one of first end and second end of a second specific side (corresponding to the second side) of the imaginary quadrangle is chamfered or cut. The peripheral surface has a first peripheral surface extending from the first side, a second peripheral surface extending from the second side, a first omitted peripheral surface extending from the first omitted side adjacent to the first peripheral surface, and a second omitted peripheral surface extending from the second omitted side adjacent to the second peripheral surface. The winding is wound about the coil winding portion and has a first end and a second end. The terminal electrodes disposed on the first flange and include a first terminal electrode and a second terminal electrode. The first terminal electrode is disposed across the first omitted peripheral surface and a part of the bottom surface. The second terminal electrode is disposed across the second omitted peripheral surface and another part of the bottom surface separated from the first terminal electrode. The first end of the winding is electrically connected to the first terminal electrode at the first omitted peripheral surface and, the second end of the winding is electrically connected to the second terminal electrode at the second omitted peripheral surface.

The particular features and advantages of the invention as well as other objects will become apparent from the following description taken in connection with the accompanying drawings, in which:

FIG. 1 is a perspective view of a coil component according to one embodiment of the present invention;

FIG. 2 is a rear view of a core in the coil component according to the embodiment;

FIG. 3 is a bottom view of the coil component according to the embodiment;

FIG. 4 is a front view of the coil component according to the embodiment;

FIG. 5 is a partial bottom view showing an arrangement of a plurality of coil components according to the embodiment;

FIG. 6 is a bottom view of a coil component according to a first modification to the embodiment;

FIG. 7 is a bottom view of a coil component according to a second modification to the embodiment; and

FIG. 8 is a bottom view of a coil component according to a third modification to the embodiment.

A coil component according to one embodiment of the present invention will be described with reference to FIGS. 1 through 4 . A coil component 1 shown in FIG. 1 primarily includes a core 2 , a single winding 6 , and terminal electrodes 7 .

The core 2 is basically made from a magnetic material such as ferrite and includes a substantially cylindrical coil winding portion 3 ( FIG. 2 ), and a first flange 4 and a second flange 5 disposed one on either end of the coil winding portion 3 . Since the first and second flanges 4 and 5 are symmetrical in shape, only the second flange 5 will be described below.

The second flange 5 is substantially plate-shaped with a prescribed thickness. The second flange 5 has a bottom surface 5 A that is substantially octagonal in shape. As shown in FIG. 3 , the bottom surface 5 A has a first side 51 , a second side 52 , a first omitted side 53 , a second omitted side 54 , a third side 55 , a fourth side 56 , a third omitted side 57 , and a fourth omitted side 58 . These sides have length equal to one another.

The first and second sides 51 and 52 are parallel sides, the first and second omitted sides 53 and 54 are disposed on one side of the first and second sides 51 and 52 . The third and fourth omitted sides 57 and 58 are disposed on the other side of the first and second sides 51 and 52 . The third side 55 is provided between the first and second omitted sides 53 and 54 , and the fourth side 56 is provided between the third and fourth omitted sides 57 and 58 . The third and fourth sides 55 and 56 are substantially parallel. These sides 51 - 58 constitute the peripheral edge of the bottom surface 5 A.

When the coil component 1 is mounted on a circuit board, the first, second, third, and fourth sides 51 , 52 , 55 , and 56 are substantially in contact with or in close proximity to the electronic parts of other neighboring coil components. When viewing the bottom surface 5 A along the direction of a line connecting the first and second flanges 4 and 5 , the first, second, third, and fourth omitted sides 53 , 54 , 57 , and 58 constitute the beveled four corners of an imaginary square constructed by extending each of the first, second, third, and fourth sides 51 , 52 , 55 , and 56 . This configuration inhibits the first, second, third, and fourth omitted sides 53 , 54 , 57 , and 58 from substantially coming into contact with other electronic parts. The bottom surface 5 A forms one end face of the core 2 and serves as a mounting surface by which the coil component 1 is surface-mounted on a circuit board (not shown).

As shown in FIG. 4 , a top surface 4 A is defined on the first flange 4 as the other end face of the core 2 . As shown in FIGS. 2 and 4 , the second flange 5 has a first peripheral surface 51 A, a second peripheral surface 52 A, a first omitted peripheral surface 53 A, a second omitted peripheral surface 54 A, a third peripheral surface 55 A, a fourth peripheral surface 56 A, a third omitted peripheral surface 57 A, and a fourth omitted peripheral surface 58 A as the peripheral surface extending from the peripheral edge of the bottom surface 5 A toward the top surface 4 A. The peripheral surfaces 51 A- 58 A extend from the corresponding sides 51 - 58 .

The winding 6 is a copper wire having an insulating coating and is wound about the coil winding portion 3 . The winding 6 has a first end 6 A and a second end 6 B electrically connected to the terminal electrodes 7 .

The terminal electrodes 7 include a first terminal electrode 7 A and a second terminal electrode 7 B. As shown in FIGS. 2-4 , the first terminal electrode 7 A is provided across the first omitted peripheral surface 53 A, a portion of the bottom surface 5 A, and the third omitted peripheral surface 57 A. The second terminal electrode 7 B is provided across the second omitted peripheral surface 54 A, a portion of the bottom surface 5 A separated from the first terminal electrode 7 A, and the fourth omitted peripheral surface 58 A. The first end 6 A of the winding 6 is electrically connected to the first terminal electrode 7 A at a portion of the first omitted peripheral surface 53 A, while the second end 6 B of the winding 6 is electrically connected to the second terminal electrode 7 B at a portion of the second omitted peripheral surface 54 A.

FIG. 5 shows an arrangement of coil components 1 having the above construction on a circuit board (not shown). The plurality of coil components 1 are mounted such that the first peripheral surface 51 A of one coil component 1 is adjacent to the second peripheral surface 52 A of another coil component 1 , and the third peripheral surface 55 A of one coil component 1 is adjacent to the fourth peripheral surface 56 A of still another coil component 1 . With this arrangement, the first omitted peripheral surface 53 A of one coil component 1 neighbors the second omitted peripheral surface 54 A of another coil component 1 . However, since the first and second omitted peripheral surfaces 53 A and 54 A are formed by chamfering the respective first and second peripheral surfaces 51 A and 52 A, the first and second terminal electrodes 7 A and 7 B formed on the respective first and second omitted peripheral surfaces 53 A and 54 A are inhibited from contacting each other directly or via solder fillets and short-circuiting. Similarly, although the first omitted peripheral surface 53 A of one coil component 1 neighbors the third omitted peripheral surface 57 A of another coil component 1 , since both surfaces are formed by chamfering, the first and second terminal electrodes 7 A and 7 B are inhibited from contacting and short-circuiting. Accordingly, the coil components 1 can be mounted at a high density.

Further, since the winding 6 is electrically connected to the terminal electrodes 7 at the first and second omitted peripheral surfaces 53 A and 54 A, the winding 6 does not reach the bottom surface 5 A by which the coil component 1 is mounted. Therefore, the height of the coil component 1 is defined merely by the distance from the bottom surface 5 A forming one end face of the core 2 to the top surface 4 A forming the other end face, enabling the coil component 1 to be formed at a low height. Further, by connecting the ends of the winding at the first and second omitted peripheral surfaces 53 A and 54 A, the connected parts can easily be seen after the coil component 1 is mounted on a circuit board. Thus, this construction facilitates external inspection of fillets and the like after the coil component 1 is mounted.

FIG. 6 shows a coil component 11 according to a first modification to the embodiment. The coil component 11 has a second flange 15 in which only a first omitted side 153 and a second omitted side 154 are formed. With this construction, ends of the winding are connected to a first omitted peripheral surface 153 A extending from the chamfered first omitted side 153 , and a second omitted peripheral surface 154 A extending from the chamfered second omitted side 154 , making it possible to form a low coil component and suitable for high-density mounting. Incidentally, the second omitted side 154 may be formed in the second flange 15 by chamfering the corner formed by a second side 152 and a third side 155 .

FIG. 7 shows a coil component 21 according to a second modification to the embodiment. The coil component 21 has a bottom surface 25 of a hexagonal shape defined by a first side 251 , a second side 252 , a first omitted side 253 , a second omitted side 254 , a third omitted side 257 , and a fourth omitted side 258 . This shape inhibits the first omitted side 253 of one coil 21 and the second omitted side 254 of another coil 21 from contacting each other and short-circuiting through solder fillets or the like when a plurality of the coil components 21 are mounted on a circuit board (not shown).

FIG. 8 shows a coil component 31 according to a third modification to the embodiment. In this coil component 31 , the corners of a quadrangle formed by a first side 351 , a second side 352 , a third side 355 , and a fourth side 356 are cut out to form a first omitted side 353 , a second omitted side 354 , a third omitted side 357 , and a fourth omitted side 358 . The coil component 31 having this construction can obtain the same effects as the coil component 1 of the above-described embodiment.

While the invention has been described in detail with reference to the specific embodiment thereof, it would be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention.