JPH0514489Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a surface-mounted inductance element used as a hybrid transformer for communication equipment, control equipment, etc.

BACKGROUND ART To take a transformer as an example of this type of surface-mounted inductance element, as shown in FIG. The end side is bent sideways from the bottom surface of the terminal block 2 and the external terminals 3, 3... are attached, and the coil 4 is wound around the winding shaft of the bobbin 1, and the coil end is attached to the external terminals 3, 3... It is known that a coil-wound body is assembled by connecting wires to the inner shaft end side of the coil-wound body, and the coil of this coil-wound body is assembled by surrounding the coil with a core 5.

In a surface mount type transformer, if the entire part including the core is exposed to the outside and remains bare, the outer shaft ends of the external terminals 3, 3... are soldered to the conductive pattern of the printed circuit board by reflow soldering etc. When fixing, the heat of the molten solder is directly transmitted to the entire device, resulting in poor solder resistance and solvent resistance, and also lacks reliability in moisture resistance after mounting.

In order to avoid this, it has been proposed to position the outer shaft end of the external terminal to the outside and mold the entire terminal including the core with a heat-resistant insulating resin (Utility Model Publication No. 54-7320).

However, when the entire body including the core is coated with resin, the magnetic properties of the core are likely to deteriorate due to the stress caused by the hardening of the resin and the stress caused by expansion and contraction due to temperature changes. This stress can be tolerated to some extent when it occurs in components with low impedance in an open magnetic circuit, but in components that form a closed magnetic circuit, the core may be separated or destroyed, resulting in a significant decrease in magnetic properties. become.

Therefore, all parts other than those that form an open magnetic path with low impedance are mounted bare as before, and
The components forming the closed magnetic circuit described above are surface mounted by manual soldering after other components are automatically mounted. However, this is not preferable because it not only takes a lot of time to mount the components, but also lacks moisture resistance and other reliability after mounting.

Problems to be solved by the invention Although the invention covers the core with a resin molded body in order to improve moisture resistance and other reliability after mounting, it does not reduce the magnetic properties of the core, and it also allows the core to be formed stably and easily. An object of the present invention is to provide a surface-mounted inductance element that can be assembled and fixed to a surface-mounted inductance element.

Means for Solving the Problems In the surface-mounted inductance element according to the present invention, the outer shaft end of the external terminal is positioned to the outside, and the coil winding body is covered with a heat-resistant resin molded body. A stepped portion of the terminal block of the coil-wound body is provided on the resin molded body, and the core is assembled and fixed to the outside of the resin molded body by being placed on the stepped portion of the resin molded body. It is configured as a surface mount type by bending the end side laterally from the bottom surface of the resin molded body.

Function In this surface-mounted inductance element, the coil-wound body is covered with a heat-resistant resin molded body, so even if reflow soldering is applied during soldering, the coil-wound body cannot be coated with solder solution or solvent. Since the coil-wound body can be shielded from moisture even after mounting, it can be configured as a highly reliable component. In addition, since the core is placed on the stepped portion of the resin molded body and assembled to the outside of the resin molded body, the core can be positioned away from the outer shaft end side where the external terminal is soldered.
Even if the core forms a closed magnetic path, the core will not be separated or damaged due to the internal stress of the resin molded body, which would reduce the magnetic properties, and the core can be stably and easily assembled and fixed to the resin molded body. be able to.

Embodiments The following description will be made with reference to FIGS. 1 to 6.

The inductance element shown in FIG. 1 is configured as a surface-mounted type similar to that shown in FIG. 7. This surface-mounted inductance element is
As shown in FIG.
The bobbin 10 is integrally molded with a. A plurality of external terminals 11, 11... are inserted and attached to the terminal blocks 10b, 10c, and the external terminals 1 protrude laterally from the terminal blocks 10b, 10c.
A coil winding body is assembled by connecting each coil end 12a, 12a... of the coil 12 wound on the winding shaft portion 10a of the bobbin 10 to the inner shaft end side 11a, 11a... of the coils 1, 11... There is.

As shown in FIG. 3, the coil-wound body is almost entirely covered with a heat-resistant resin molded body 13 with the outer shaft end sides 11b, 11b... of the external terminals 11, 11... led out to the outside. . To form this resin mold body 13, left and right terminal blocks 10b, 10
A stepped portion 13a is provided at the base plate portion that takes in both c, and the recessed portion 13 is
By providing the flange portion 13c exhibiting b on the upper side, a core assembly portion to be described later can be formed.

For this resin molded body 13, EE, EI
The cores 14a and 14b forming a closed magnetic path are fitted into the recess 13b from the outside of the resin molded body 13, and are fixedly assembled by being fixed with adhesive tape, clips, or the like. The cores 14a, 14
When assembling b, each core 14a, 14b is slid on the step 13a of the resin molded body 13, and the central leg is inserted into the cylinder position formed by the winding shaft part 10a of the coil winding body, The coil can be fitted and fixed into the recess 13b so that the outer legs surround the coil. Thereby, the cores 14a and 14b can not only be easily assembled to the resin molded body 13, but also can be more stably and reliably fixed to the resin molded body 13 by using the collar portion 13c as a holding portion.

After molding the resin mold body 13, the external terminal 1
Outer shaft end side 1 protruding vertically outward of 1, 11...
1b, 11b... are bent along the outer surface from the bottom to the side surfaces of the resin molded body 13,
As shown in FIG. 4, it can be formed as a lead terminal that can be applied to a surface mount type. according to this,
Terminal block 1 is assembled by bending the external terminal into a U-shape in advance.
Rather than attaching the coil ends 12a, 12a... of the coil 12 to the external terminals 11, 11...
Since the wires can be automatically connected to the inner shaft ends 11a, 11a, . . . , the coil ends can be wired efficiently and costs can be reduced.

In the surface-mounted inductance element configured in this way, the outer shaft ends 11b, 1 of the external terminals 11, 11, .
1b... can be attached to the printed circuit board by soldering and fixing them to the conductive patterns of the printed circuit board. At the time of soldering, it can be processed together with other parts by applying reflow soldering. Moreover, even if the heat from the molten solder acts on the resin mold 13 during this soldering,
Since the resin molded body 13 is made of a heat-resistant resin, the resin molded body 13 itself blocks the heat generated by the molten solder, so that the coil wrapping body housed inside the resin molded body 13 receives no heat. You can prevent it from affecting you. At the same time, it is also possible to prevent solder solvents, moisture from the outside air, etc. from acting on the coil-wound body. Further, the cores 14a and 14b are placed on the stepped portion 13a of the resin mold body 13, and the external terminal 1
Outer shaft end side 11b, 1 to be soldered to 1, 11...
1b..., the resin molded body 13 itself can block the heat of the molten solder from reaching the cores 14a, 14b. its core 1
Since 4a and 14b are assembled outside the resin molded body 13, it is also possible to prevent the internal stress of the resin molded body 13 from acting on the cores 14a and 14b.

As shown in FIG. 5, the resin molded body 13 partially exposes the stopper flange 10d of the coil 12 to the shaped surface of the recess 13b, and also allows the terminal blocks 10b, 10
The upper surface and left and right end surfaces of c can be formed so as to be exposed to the shaped surface of the stepped portion 13a. This resin molded body 13 is preferable because the overall volume can be made relatively small and the mounting area on the printed circuit board can be reduced. In addition, as shown in FIGS. 5 and 6, the flange 13c of the resin molded body 13 has a recess 13d on one of the four sides that indicates the direction of the transformer, for example, the primary side of the coil 12. can be provided. The recessed portion 13d can be detected by an optical processing means when the board is mounted, and can be used to specify the orientation associated with automatic mounting.

In the embodiments described above, including this modification, EI,
Although an inductance element in which a closed magnetic path is formed by assembling cores 14a and 14b such as an EE type is illustrated,
In addition, the present invention can also be applied to a case where a low impedance surface-mounted inductance element is configured in an open magnetic path. Moreover, the coil wrapping body can be constructed of a toroidal type.

Effects of the Invention As described above, according to the surface-mounted inductance element according to the present invention, the coil winding body is covered with a heat-resistant resin molded body, and the core is placed on the stepped portion of the resin molded body. Since the core is assembled externally, the core can be positioned at a distance from the outer shaft end side where the external terminal is soldered, and even when forming a closed magnetic circuit, the magnetic properties are not impaired during soldering by automatic mounting, and the core is solvent resistant. It can also be constructed as an extremely reliable component by imparting durability and moisture resistance. Further, since the core is assembled and fixed by being placed on the stepped portion from the outside of the resin molded body, the core can be stably and easily assembled to the resin molded body.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing a surface-mounted inductance element according to the present invention, Fig. 2 is a perspective view showing a coil-wound body of the element, and Fig. 3 is an overall view showing the core of the element in an expanded state. FIG. 4 is a perspective view of the overall appearance of the core in an assembled state; FIG. 5 is a perspective view of the surface mount type inductance element according to another embodiment of the present invention with the core in an expanded state. figure,
FIG. 6 is a side sectional view of the entire core in an assembled state, and FIG. 7 is an explanatory diagram showing a surface-mounted inductance element according to a general example.

Claims (1)

[Scope of utility model registration request] A bobbin is provided, in which the winding shaft of the coil and a terminal block to which multiple external terminals are attached are integrally molded, and the coil is wound around the winding shaft of the bobbin, and each coil end is connected to the inner shaft end of the external terminal. In a surface mount type inductance element, the outer shaft end of the external terminal is led out to the outside, and the coil is connected to the surface of the surface mount type inductance element. The winding body is covered with a heat-resistant resin mold body, a stepped portion is provided on the resin mold body by the terminal block of the coil winding body, and the core is placed on the stepped portion of the resin mold body. What is claimed is: 1. A surface-mounted inductance element, characterized in that the external terminal is assembled and fixed to the outside of the body, and the outer shaft end side of the external terminal is bent laterally from the bottom surface of the resin molded body to form a surface-mounted type.