JP2001006940A - Surface mount toroidal coil. - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve workability by housing a toroidal case obtained by winding a flat wire as a conductor in the recessed section of a case, and laying the terminals of the coil led out to the external surface of the case in grooves continuously provided from the bottom face of the outer edge section of the case as outside connecting terminals. SOLUTION: After a flat soft copper wire is wound around a ring core by a prescribed number of turns, the winding end terminals of the coil are led out to circularly symmetrical positions which are separated from each other by about 180 deg.. Then a toroidal coil is formed by removing the insulating coating film of the coil from the two terminals and coating the terminals with solder. Thereafter, the terminals of the toroidal coil are inserted into the through holes 5 of the bottom face of a case having a recessed section, chamfered four corners, and the through holes 5 and grooves 6 from above. Finally, a surface mounting toroidal coil is formed by leading out the terminals to the rear surface of the case and burying the terminals in the grooves 6 by bending the terminals at about right angles. Thus, a small-sized toroidal coil having a large electric capacity can be manufactured without requiring the soldering work of the terminals of the coil to the outside connecting terminals of the case.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface-mounted toroidal coil mounted on a substrate for reducing noise of a power supply of a small electronic device such as a notebook personal computer.

[0002]

2. Description of the Related Art A printed multilayer type in which a ferrite and an electrode pattern are alternately printed and integrally fired for a signal having a small current capacity as a surface mount inductor corresponding to a demand for miniaturization and low profile of electronic equipment. And, there is a laminated multilayer type in which an electrode pattern is printed on a ferrite green sheet, laminated, and fired integrally. However, those with a large current capacity have a large shape and are not on the market.

[0003] A coil having a large current capacity of several amperes or more for a power supply circuit stores a toroidal coil in which a copper round wire is wound around a ring core constituting a closed magnetic circuit in a case in which external connection terminals are embedded. The terminal of the coil was connected by soldering to the external terminal.

[0004] When a surface-mounted toroidal coil is made to be a sealed type, an external connection terminal is soldered to the coil and integrally molded, or the coil is placed in a case in which the external connection terminal is embedded, and the coil terminal is connected to the external connection terminal. After soldering, epoxy resin was cast and cured.

[0005]

When a copper round wire is wound around a ring core, a thin wire is better for increasing the number of windings, and a thick wire is better for increasing the current capacity. Although there was a limit to the size reduction of a coil having a large size, it was still further downsizing.

In addition, when the case is housed in a case, the case portion in which the external connection terminals are buried becomes a dead space, which has been a problem in downsizing the case. Further, the work of soldering and connecting the terminals of the coil to the external terminals is complicated and reduces reliability, and furthermore, the work of fixing the toroidal coil to the case with an adhesive or the like is necessary. Another object of the present invention is to eliminate complicated work and further reduce the size.

[0007] In the manufacture of a sealed type surface mount toroidal coil, an epoxy resin is cast into a case, or the case is made larger, covered, and the outer periphery is bonded. This is to eliminate such work and to further reduce the size.

[0008]

Means for Solving the Problems A first invention of the present invention is:
In a surface-mounted toroidal coil in which a toroidal coil in which a copper wire is wound around a ring core is housed in a case, the toroidal coil wound using a rectangular wire as a conductor is housed in a case recess, and the terminal of the toroidal coil is placed on the outer surface of the case. The case is provided on the outer surface and is laid in a groove following the bottom surface of the edge of the case to form an external connection terminal.

According to a second aspect of the present invention, in a surface-mounted toroidal coil, the toroidal coil is housed in a case recess, and terminals of the toroidal coil are connected to the outside of the case through a through hole formed in the outer peripheral portion of the bottom surface of the recess. It is characterized in that it is led out to the bottom surface, laid in a groove connected to the bottom surface of the outer peripheral portion formed adjacent to the through hole, and connected to an external connection terminal. This allows the toroidal coil to be fixed to the case at the terminal end,
By providing both functions of forming external connection terminals, downsizing and man-hour reduction can be achieved.

According to a third aspect of the present invention, in a surface-mounted toroidal coil, two terminals of the toroidal coil led out to the bottom surface of the case are folded and arranged, and the external connection terminal is fixed in a groove of the external connection terminal. It is characterized in that it has been expanded to at least twice the line width of the rectangular wire.

According to a fourth aspect of the present invention, the toroidal coil is housed in a case recess, the terminal of the toroidal coil is led out to the outer surface of the case, and the terminal of the toroidal coil is provided in a groove provided on the outer surface of the case and connected to the bottom of the outer surface of the case. The external connection terminal is formed by wire connection, and the terminal of the terminal is inserted and fixed in a hole provided at the end of the groove.

When the rectangular wire is thick and hard, the strength of the external connection terminal is obtained. However, when the rectangular wire is thin and soft, it is necessary to fix it to the groove of the case with an epoxy resin or the like. If the adhesive adheres, the solder will not be adhered, so it is necessary to be careful. Workability is improved by providing a hole at the end of the extended external connection terminal and inserting and fixing the terminal end. It is also possible to attach an adhesive such as epoxy resin to this hole and fix it,
Since it is separated from the external connection terminal portion, the external connection terminal portion is not contaminated with the resin and the solderability is not deteriorated.

According to a fifth aspect of the present invention, in the case where the surface-mounted toroidal coil is of a sealed type, the toroidal coil is housed in a concave portion of the case, and a lid is mounted on the toroidal coil so that the central space of the toroidal coil is provided. The part is fitted with the lower case. In this case, the external connection terminal may be provided on the top or bottom surface of the case, or may be provided on the upper lid (upper case).

More specifically, the present invention for solving the above-mentioned problem is to provide a winding wire by using a rectangular wire having a rectangular cross section instead of a round wire as a wire material for winding to a ring core, and winding the rectangular wire upright. The number of times can be increased and the current capacity can be increased. If the wire is wound without forming a rectangular wire, the number of windings is reduced, but the thickness of the conductive wire is reduced, and the wire can be wound on a low-profile toroidal coil. Further, the present invention is characterized in that the flat wire coil terminal is fixed to the groove of the case to serve as an external connection terminal.

The shape of the case for accommodating the toroidal coil may be any shape. For example, the toroidal coil is accommodated in a case recess having an outer shape obtained by chamfering a rectangular corner as shown in FIG. An external connection terminal is formed by pulling out and bending the terminal terminal into a groove provided adjacent to the through hole in the chamfered corner bottom surface. The case material is preferably a heat-resistant epoxy resin or polybutylene terephthalate resin that can withstand the soldering temperature of the reflow furnace.

When the external connection terminal portion is narrow using a rectangular wire having a small line width, two terminals of the toroidal coil led out to the bottom of the case are folded and arranged side by side as shown in FIG. , And the external connection terminal portion can be easily expanded to twice or more the line width of the rectangular wire. This provides a sufficient soldering area for mounting on a substrate. In addition, the groove of the external connection terminal portion of the case is formed in such a shape that the terminal of the folded coil can be stably accommodated.

Further, using a case as shown in FIG. 5, the coil terminal is pulled out from the groove on the upper surface of the case, and the coil terminal is laid in the groove on the bottom surface of the case through the groove on the side surface of the case corner to form an external connection terminal. Can also be formed. In this case, since there is no through hole in the bottom of the case, the flux does not enter the inside of the case when mounted on the board and soldered.

Further, in the case where the hardness is insufficient with a thin rectangular wire as the external connection terminal, the terminal of the coil terminal is extended along a groove extending from the external connection terminal portion as shown in the sectional view of FIG. By bending into the hole and inserting and fixing, necessary strength as an external connection terminal is provided. Further, an adhesive such as an epoxy resin may be injected into the hole to be hardened and fixed. Even if the epoxy resin flows, it is separated from the external connection terminal, so that the epoxy resin adheres to the external connection terminal and is soldered. It does not detract from sex.

When a single coil is constructed, as shown in FIG. 2, the coil terminal at the end of winding, in which a rectangular wire is wound around the ring core, is drawn out to a symmetrical position from the winding start position, is put into the case recess. Since the coil terminal is formed into the external connection terminal by bending through the hole on the bottom of the case, the toroidal coil is stably fixed to the case.
Since the external connection terminals of the case are also symmetrical, they are stable even when mounted on a substrate.

In the case of forming a common mode coil, as shown in FIG. 3, two coils are formed by winding each half of the ring core, and four terminals are placed in a case shown in FIG. To be embedded in the groove following the bottom surface of the outer edge of the case, and to fold the terminal end into two, fixed in the external connection terminal groove and increasing the soldering area to form the external connection terminal. Can be.

The case is sealed by providing a fitting portion in the center of the upper and lower cases, that is, in the center space of the toroidal coil, as shown in the cross-sectional view of FIG. In addition, the sealing of the toroidal coil can be easily performed, and the case size does not increase. Further, the complicated work of casting a certain amount of resin as in the related art is eliminated. Further, since the upper surface becomes smooth, a vacuum chuck method can be used for the substrate mounting machine (mounter).

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment (1) of the present invention will be described below with reference to the drawings. Thickness; 0, 0
A 2 mm amorphous nanocrystalline alloy thin plate (manufactured by Alps Electric Co., Ltd .; Nanopalm) was wound up, and as shown in FIG.
Outer diameter: 20mmΦ, inner diameter: 7mmΦ tail, thickness: 2mm ring core formed, dicing saw width: 0, 2mm
After the slits were formed, they were coated with an epoxy resin and insulated.

The ring core has a thickness of 0, 35 mm,
Width: A rectangular copper wire of 0,7 mm is wrapped around the ring core for 16
After winding, the end-of-winding terminal was pulled out at a symmetrical position rotated by approximately 180 degrees, the insulating film of the two terminals of the coil was removed, and solder coating was performed to form a toroidal coil shown in FIG.

Next, the terminal of the toroidal coil was chamfered at its center as shown in FIG. 4 with four concaves of 21 mmφ, depth: 3.0 mm, outer shape: 23 mm square, thickness: 3, 5 mm. A through-hole was inserted through the through-hole on the bottom of the case having a through-hole and a groove on the bottom, pulled out to the back of the case, bent at a substantially right angle, and embedded in the groove 6 for the external connection terminal to form a surface-mounted toroidal coil. The removal of the insulating film of the terminal and the terminal treatment of the solder coat may be performed after the terminal is housed in the case, or the terminal may be fixed to the external connection terminal groove using epoxy resin.

Next, an embodiment (2) will be described with reference to the drawings. A toroidal coil similar to that of the embodiment (1) is housed in a case having no through hole shown in FIG. 5 with the coil terminal facing upward, and the terminal is placed along the groove provided on the outer surface of the case. The external connection terminal was formed by laying down to the bottom of the part.

Next, an embodiment (3) will be described with reference to the drawings. As in the embodiment (1), the rectangular wire is wound nine turns at a time on a ring core without a slit having the same outer shape as that of FIG. 1 to form two coils, and a terminal treatment is performed. A coil was formed. Next, the four terminals of the coil are inserted into the through holes from the upper surface of the case shown in FIG. Was completed.

Next, an embodiment (4) will be described with reference to the drawings. As in the case of the embodiment (1), FIG.
The terminal of the toroidal coil is inserted into the through hole 5 in the outer periphery of the concave portion of the case 4 shown in FIG. 7 to house the coil, and the terminal is laid along a groove 6 provided on the outer surface of the case, The terminal terminal was bent and embedded in the hole 7 to fix the external connection terminal.

Next, an embodiment (5) will be described with reference to the drawings. It has the same through-holes and external connection terminal grooves as the embodiment (1), and is further housed in a case shown in the sectional view of FIG. After forming the external connection terminals in the same manner as described above, the upper lid was fitted into the case to form a closed surface mount toroidal coil.

[0029]

As described above, according to the method of the present invention, a toroidal coil in which a rectangular wire is wound around a ring core is housed in a case, and the coil terminals are led out of the case and provided on the outer surface. Since the external connection terminals are laid in the grooves, a small surface mount toroidal coil having a large current capacity can be manufactured, and the work of soldering the coil terminals to the case external connection terminals can be reduced. Further, the soldering area of the external connection terminals can be increased by folding and arranging the terminals.

[Brief description of the drawings]

Fig. 1 Ring core with slit

FIG. 2 Toroidal coil

FIG. 3 is a common mode coil

FIG. 4 Case for two terminals (with through holes)

FIG. 5: Case for two terminals (without through-hole)

[Fig. 6] Case for 4 terminals (with through holes)

FIG. 7 is a case for two terminals (with a through hole and a terminal terminal fixing hole).

FIG. 8: Case with lid

FIG. 9: Folding external terminal connection section

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Ring core 2 ... Slit 3 ... Flat copper wire 4 ... Case 5 ... Through-hole 6 ... Groove 7 ... Top lid 8 ... Fitting part 9 ... Folding external terminal connection part

Claims (5)

[Claims] 1. A surface-mounted toroidal coil in which a toroidal coil in which a copper wire is wound around a ring core is housed in a case, wherein the toroidal coil in which a rectangular wire is used as a conductor is housed in a case recess, A surface mounting toroidal coil, wherein the terminal is led out of the case and laid in a groove following the bottom surface of the outer edge of the case to form an external connection terminal. 2. The surface-mounted toroidal coil according to claim 1, wherein the toroidal coil formed by winding a flat wire is housed in a case recess, and a terminal of the toroidal coil is formed in an outer peripheral portion of a bottom surface of the case recess. A surface-mounted toroidal coil that is led out to the outer bottom surface of the case. 3. The surface-mounted toroidal coil according to claim 1, wherein the terminals of the toroidal coil are folded and arranged, and the external connection terminal is extended to at least twice the line width of the flat wire. Surface mount toroidal coil. 4. The surface-mounted toroidal coil according to claim 1, wherein the terminal of the external connection terminal is embedded in a hole provided at the end of the groove on the outer surface of the case. coil. 5. The surface-mounted toroidal coil according to claim 1, wherein an upper lid is attached to the surface-mounted toroidal coil, and the lower case is fitted in a central space of the toroidal coil. coil.