JP2584909Y2 - Surface mount transformer - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface mount transformer mounted on a printed circuit board.

[0002]

2. Description of the Related Art Conventionally, in an electronic device such as a switching power supply device, a printed circuit board on which a pattern is formed has been used to mount electronic components such as a transformer, a choke coil, and a capacitor and to perform wiring between these components. Used. And, as the printed circuit board, a pattern is formed on the lower surface, and a conductive pin inserted from the upper surface is soldered to the pattern on the lower surface.
In the printed circuit board with the pattern formed on the lower surface, the lower ends of the conductive pins and the soldered portions protrude from the lower surface, and the mounted electronic components are relatively large. Therefore, in order to reduce the size of this type of switching power supply,
A so-called surface mount type in which electronic components are mounted on a printed circuit board having a pattern formed on the upper surface is used. For example, a surface mount transformer in which a pair of upper and lower EE type cores is vertically installed, and between these EE type cores. The winding bobbin main body is installed vertically, mounting legs for electrically connecting the windings are provided at the lower portion of the bobbin, and the mounting legs are soldered and fixed to a pattern on the upper surface of the printed circuit board.

[0003]

In the above prior art, in order to reduce the size of the power supply device, when the thickness of the surface mount transformer mounted on the printed circuit board is reduced, the height of the bobbin body must be reduced. However, when the bobbin main body is formed thin, the winding width of the winding is restricted, and there is a problem that the bobbin cannot be used for a transformer having a relatively large capacity.

In order to deal with such a problem, a microfilm disclosed in Japanese Utility Model Application No. 58-77179 (Japanese Utility Model Application Laid-Open No. Sho 59-182905) and a Japanese Patent Application No. 53-158047 (Japanese Utility Model Application Laid-Open No. By forming a pair of upper and lower pot-shaped cores or magnetic cores into a flat and thin microfilm, the bobbin to be housed inside these pot-shaped cores and magnetic cores is formed into a large diameter, and a lead wire wound around the bobbin Also, there is disclosed a configuration in which the number of turns and the winding diameter of the lead portion are increased.

However, in such a configuration, even when the lead wire or the lead portion is a single winding, or when a band-type lead wire or a lead portion is used, for example, the end portions of these lead wires or the lead portion are used. Unnecessary terminals that are not connected remain as they are, so that there is a concern that a part of the mounting space is wastefully occupied.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems and to provide a surface-mounting transformer capable of securing a capacity and reducing the mounting space while being thinner.

[0007]

According to the present invention, there is provided a bobbin main body on which a winding is wound, a pair of upper and lower cores having a groove portion for accommodating the bobbin main body and forming a flat shape, and the bobbin main body. Mounting legs protruding laterally from the core, an opening that opens into the side surface of the core and through which the mounting legs are inserted, and is provided at an end of the mounting leg, and each end of the winding is connected to the outside. A conductive pin for electrical connection, and a groove formed in the mounting leg portion for cutting an unnecessary portion of the conductive pin of the mounting leg portion.

[0008]

[Function] A pair of upper and lower cores are formed flat and thin, and a bobbin body to be housed inside the cores is formed to have a large diameter, thereby making the transformer thin and winding the bobbin body. The diameter can be made large. In the case of a single winding or a winding using a copper band, the mounting space of the surface mount transformer can be reduced by cutting the conductive pin portion of the mounting leg from the notch groove or the notch groove.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 4 show an embodiment of the present invention, wherein 1 is a metal core substrate which is a printed circuit board,
In the metal core substrate 1, an insulating layer is formed on the surface of an aluminum base, and a predetermined printed wiring process is performed on the insulating layer. Reference numeral 2 denotes a surface mount transformer mounted at a predetermined position on the metal core substrate 1. This surface mount transformer 2
A hollow bobbin main body 4 made of a synthetic resin or the like having a winding 3 wound around its outer periphery is formed in a flat shape. For example, the bobbin main body 4 has a diameter of 5 mm in height and an inner diameter of 10 mm. In the upper and lower flange portions 5 of the bobbin main body 4, a plurality of elongate injection holes 6 are formed at regular intervals. In addition, primary and secondary mounting legs 7, 8 for making electrical connection to the outside are provided on both sides of the lower flange portion 5 of the bobbin main body 4 so as to protrude therefrom. Numeral 8 is a substantially T-shaped plane, and four conductive pins 9 are provided at its ends at predetermined intervals, and each end of the winding 3 is electrically connected to these conductive pins 9. Have been. The bobbin main body 4 is housed in a pair of upper and lower cores 10 having a flat and substantially cylindrical shape,
The core 10 has a substantially cylindrical side wall 11 and a cylindrical center 12.
A storage groove 13 for storing the bobbin main body 4 is formed between the upper and lower surfaces 15, 15, and a notch groove-shaped opening 14 for inserting the base of each of the mounting legs 7, 8 is formed. The lower surface 15 and the lower surface of the conductive pin 9 are formed at the same height. The mounting leg 7 on the primary side
Are formed with two notches 16 sandwiching the two conductive pins 9 at the center, and two notch grooves 16 sandwiching the two conductive pins 9 at the center in the mounting leg 8 on the secondary side. One notch groove 16A is formed on the base 16 and the base side, and these notch grooves 16 and 16A are formed in the upper and lower surfaces of the mounting legs 7 and 8 in the form of cuts.

Then, the winding 3 is applied to the bobbin main body 4, each end of the winding 3 is electrically connected to each conductive pin 9, and the injection hole 6 is formed in the flange 5 of the bobbin main body 4. An impregnating agent or the like (not shown) is injected into the winding 3. Thereafter, the bobbin main body 4 is aligned with the storage groove 13 and the bobbin main body 4 is inserted into the upper and lower cores 10, 10.
And the surface mount transformer 2 is assembled. The surface mount transformer 2 is mounted on the metal core substrate 1 such that the lower surface 15 of the core 10 abuts, and the conductive pins 9 are electrically connected to the pattern of the metal core substrate 1 by soldering or the like and fixed. . The surface mount transformer 2 is made thin by forming the pair of upper and lower cores 10 and 10 in a flat shape, so that the power supply device equipped with the surface mount transformer 2 can be downsized. By forming the bobbin main body 4 housed in 10 thin and having a large diameter,
The winding number and the winding diameter of the winding 3 wound around the bobbin main body 4 can be increased, and can be used as the large-capacity surface mount transformer 2. In addition, since the injection hole 6 is formed in the flange portion 5 of the bobbin main body 4, the winding is filled with an impregnating agent or the like from the injection hole 6, and the entire winding 3 is protected by the impregnating agent. A stable operation of the transformer becomes possible. In the case where the single winding 3 is used in such a surface mount transformer 2, the mounting legs 7 and 8 are used.
Unnecessary conductive pins 9 are cut off from the notched grooves 16 of FIG. Further, when a band type such as a copper plate (not shown) is used instead of the winding 3 on the secondary side, the conductive pin 9 of the mounting end 8 is cut from the cutout groove 16A on the secondary side. .

As described above, according to the above embodiment, the winding 3
The bobbin main body 4 around which the bobbin main body 4 is wound, a pair of upper and lower cores 10, 10 each having a flat portion and having a groove 13 for accommodating the bobbin main body 4, Attachment legs 7 and 8 for making electrical connection, opening 14 opened at the side surface of core 10 and through which attachment legs 7 and 8 are inserted, and provided at the ends of attachment legs 7 and 8 A conductive pin 9 for electrically connecting each end of the mounting leg 3 to the outside; and a notch groove formed on the mounting legs 7 and 8 for cutting unnecessary portions of the conductive pins 9 of the mounting legs 7 and 8. 16 and 16A, the upper and lower pair of cores 10 and 10 are formed to be flat and thin, and the bobbin main body 4 housed inside the cores 10 and 10 is formed to have a large diameter. Thinning the mounting transformer 2 and winding 3
, The winding number and the winding diameter can be made large, and the capacity of the surface mount transformer 3 can be secured, and the thickness can be significantly reduced.

Further, the pair of upper and lower cores 10 and 10 are formed flat and thin, and the bobbin main body 4 housed inside the cores 10 and 10 is formed to have a large diameter. While securing and enabling thinning, those using a single band or copper band as the winding 3 are:
By cutting the conductive pins 9 of the mounting legs 7, 8 from the notch groove 16 or the notch groove 16A, the surface mount transformer 2 is cut.
Mounting space can be reduced.

Further, as an effect of the embodiment, since the injection hole 6 is formed in the flange portion 5 of the bobbin main body 4, an impregnating agent or the like can be injected into the entire winding 3 provided on the bobbin main body 4, With this impregnating agent, the performance of the surface mount transformer 2 against vibration and impact can be improved. Also, core 10
Is formed at the same height as the lower surface of the conductive pin 9, the surface mount transformer 2 mounted on the metal core substrate 1 has the entire planar lower surface 15 of the core 10 abutting on the metal core substrate 1. Since heat is absorbed by the metal core substrate 1 from the contact portion, the cooling effect is excellent, and the operation performance of the transformer is improved. Furthermore, since the bobbin main body 4 is housed in the substantially cylindrical upper and lower cores 10, 10, there is a possibility that an operator may come into contact with the winding 3 of the bobbin main body 4 during the mounting work of the surface mount transformer 2, for example. In addition, the winding 3 can be stably protected from the outside.

The present invention is not limited to the above embodiment, and various modifications can be made within the scope of the present invention. For example, in the embodiment, the cylindrical bobbin main body is shown, but the bobbin main body may be formed in a rectangular cylindrical shape, and in this case, the outer shape of the core may be formed in a flat and rectangular shape. Also, the printed circuit board is not limited to a metal core substrate using an aluminum base, and various types can be used.

[0015]

According to the present invention, a bobbin main body around which a winding is wound, a pair of upper and lower cores having a groove portion for accommodating the bobbin main body and forming a flat shape, and a lateral side from the bobbin main body. At the end of the mounting leg that protrudes, a conductive pin for electrically connecting each end of the winding to the outside is provided at an end of the mounting leg, and a groove for cutting the conductive pin is formed,
An opening that is opened on a side surface of the core and through which the mounting leg is inserted; a conductive pin that is provided at an end of the mounting leg and electrically connects each end of the winding to the outside; A groove formed in the leg portion to cut off the unnecessary conductive pin portion of the mounting leg portion, which can secure the capacity and can be made thinner, yet still reduce the mounting space. And a surface mount transformer capable of providing the same.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of the present invention.

FIG. 2 is a partially cutaway plan view showing an embodiment of the present invention.

FIG. 3 is an exploded perspective view showing one embodiment of the present invention.

FIG. 4 is a side view of the mounting leg according to the embodiment of the present invention;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal core board 2 Surface mount transformer 3 Winding 4 Bobbin main body 7, 8 Mounting leg 9 Conductive pin 10 Core 14 Opening 16, 16A Notch groove (groove)

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁶ , DB name) H01F 17/04 H01F 27/00 H01F 27/28 H01F 27/29 H01F 27/32

Claims (1)

(57) [Scope of request for utility model registration] 1. A bobbin main body around which a winding is wound, a pair of upper and lower cores having a groove portion for accommodating the bobbin main body and having a flat shape, and a mounting projecting laterally from the bobbin main body. A leg, an opening that is opened in a side surface of the core and through which the mounting leg is inserted, and a conductive member that is provided at an end of the mounting leg and electrically connects each end of the winding to the outside. A surface mount transformer comprising: a pin; and a groove formed in the mounting leg, the groove cutting the unnecessary conductive pin portion of the mounting leg.