KR20240139347A - Mold type transformer having improved heat protection structure - Google Patents

Abstract

The present invention provides a transformer that is completed by assembling a primary bobbin having a primary coil wound inside and a secondary bobbin having a secondary coil wound outside to produce a bobbin module, and then injection-molding a molding portion and a side flange onto the bobbin module through an injection molding process.

Description

Mold type transformer having improved heat protection structure

The present invention relates to a molded transformer having an improved heat dissipation structure.

SMPS(Switched-mode power supply) is an electronic circuit that switches power using a switching device that turns on and off at a high frequency, and a storage element such as an inductor or capacitor that transmits power when the switching device is in a non-conducting state. SMPS is highly efficient and is widely used in electronic equipment such as computers that require a stable and efficient power supply. For example, it is applied to UHD, FHD, HD LED TVs and monitors.

SMPS is classified into AC-DC, DC-DC, DC-AC, and AC-AC according to the input/output voltage, and AC-DC SMPS typically has an inverter consisting of an input rectifier and filter, a switching device, an output rectifier and filter, a control circuit, and a transformer. The transformer here is a so-called “switching transformer,” and compared to general transformers, it can significantly reduce the size of the core and bobbin, and has the advantage of being able to stably supply low-voltage, low-current power.

However, conventional transformers have a problem in that they do not sufficiently consider heat dissipation functions. For example, Patent Publication No. 10-2015-0045694 discloses a transformer in which a coil is wound on a bobbin and a core is inserted and mounted on the bobbin. However, in this device, when the core or coil dissipates heat, the heat is directly released through the side of the core, so there is a concern that the transformer or surrounding micro-components may be thermally deformed or their performance may deteriorate. Referring to Patent Publication No. 10-2012-0076299 regarding “Transformer and Flat Panel Display Device Having the Same,” there is a high concern that the above-mentioned problems may occur because the core is installed to directly penetrate the PCB substrate.

In addition, the transformer's bobbin is composed of a primary bobbin on which the primary coil is wound, and a secondary bobbin on which the secondary coil is wound. In order to secure the insulation distance between the coils, a separate insulator is sometimes inserted or the bobbin size is increased to secure the insulation distance. However, in this case, there is a disadvantage in that the volume of the transformer increases.

Therefore, in the development of SMPS, it is necessary to improve the insulation between coils and the heat dissipation effect of the coil and core.

The present invention has been completed based on the above findings.

The purpose of the present invention is to provide a transformer that can be miniaturized and slimmed down by improving insulation between windings (primary side/secondary side) and heat dissipation effect for wire/core heat generation by applying a novel bobbin structure and manufacturing method to the transformer.

In order to achieve the above-described purpose, the present invention provides a transformer, which comprises a transformer having an inner primary bobbin having a primary coil wound thereon, and an outer secondary bobbin having a secondary coil wound thereon, which are formed by pre-assembling a bobbin module, and then injection-molding a molding part onto the bobbin module through an injection molding process, wherein the molding part includes a side flange formed on the upper or lower side of the side of the molding part to release heat of a core mounted on the primary bobbin and the secondary bobbin.

The above core includes an E-type core and an I-type core, and the side flange can be formed adjacent to the side on which the “”-type core is mounted.

One surface of the side flange can be in contact with the ends of the left and right legs of the E-type core, and the other surface of the side flange can be in contact with the exposed surfaces of the protruding sides of the I-type core.

The above side flange is composed of a contact portion that extends thinly from the inside to the outside of the transformer and an extended portion that extends briefly upward and downward from the outer end of the contact portion, and at least the contact portion can contact the exposed surfaces of the ends of the left and right legs of the E-type core and the protruding sides of the I-type core.

The ends of the middle, left leg and right leg of the E-type core can be arranged to form a slight gap with each corresponding face of the I-type core.

When forming the above molding part, a barrier wall made of insulating material and having a thickness of 1 mm or less can be formed between the primary coil and the secondary coil.

In addition, the present invention provides a method for manufacturing a transformer, comprising: assembling a primary bobbin having a primary coil wound inside and a secondary bobbin having a secondary coil wound outside, which constitute a transformer, to form a bobbin module, and then injection-molding a molding part on the bobbin module through an injection molding process to complete the module; the method includes: forming a molding part to release heat of a core mounted on the primary bobbin and the secondary bobbin, and forming a side flange for heat dissipation in a longitudinal direction of the transformer on the upper or lower side of the side surface of the molding part.

The step of forming the above side flange may include the step of forming a contact portion that extends thinly from the inside of the transformer toward the outside, and an extended portion that extends briefly upward and downward from the outer end of the contact portion.

According to the present invention, the insulation distance between the primary coil and the secondary coil is minimized, that is, the insulation distance between the primary and secondary coils is minimized through an injection molding process after assembling the primary coil member and the secondary coil member, thereby enabling a design of a miniaturized and slim transformer, and since the winding coupling can be arbitrarily adjusted, it is possible to easily design the leakage inductance of the SMPS circuit design value.

According to the present invention, a wire heat shielding effect is possible due to a coil part injection molding structure, and a structure for dispersing core heat is possible by applying the smart gap (side gap and center gap) technology of the core, so that the core size can be miniaturized and slimmed down and the wire diameter can be reduced.

FIG. 1a is a drawing explaining a process for manufacturing a primary bobbin of a transformer, FIG. 1b is a drawing explaining a process for manufacturing a secondary bobbin of a transformer, and FIG. 1c is a drawing explaining a process for manufacturing a final transformer by combining and molding a primary bobbin and a secondary bobbin and combining a core;
FIG. 2a is an upper perspective view for explaining the heat dissipation structure of the transformer of the present invention, FIG. 2b is a cross-sectional view taken along the AA portion in FIG. 2a after assembly is completed, FIG. 2c is a lower perspective view for explaining the heat dissipation structure of the transformer of the present invention, and FIG. 2d is a cross-sectional view taken along the BB portion in FIG. 2c after assembly is completed;
FIG. 3 is a drawing conceptually explaining the arrangement structure of the core and the flat core of the present invention to enhance the heat dissipation effect;
FIG. 4 is a cross-sectional view showing a member involved in heat dissipation to specifically explain the heat dissipation effect of the present invention;
Fig. 5 is a cross-sectional view showing the formation of a partition between the primary coil and the secondary coil while forming the molding part;
Figure 6 is a top perspective view (Figure 6a) showing the final assembly of the transformer in Figures 2c and 2d, and a bottom perspective view (Figure 6b) looking upside down; and
Figure 7 is a top perspective view (Figure 7a) showing the final assembly of the transformer in Figures 2a and 2b, and a bottom perspective view (Figure 7b) looking over it.

Hereinafter, preferred embodiments of the present invention will be described with reference to the attached drawings.

First, the manufacturing process of the molded transformer (1) of the present invention will be described.

FIG. 1a is a drawing explaining a manufacturing process of a primary bobbin (2) of a transformer (1), FIG. 1b is a drawing explaining a manufacturing process of a secondary bobbin (4) of a transformer (1), and FIG. 1c is a drawing explaining a process of combining and molding a primary bobbin (2) and a secondary bobbin (4) and combining a core (6) to manufacture a final transformer (1). Descriptions of parts of the manufacturing process of the transformer (1) that are obvious to those skilled in the art or that are not related to the present invention are omitted.

In Fig. 1a, after preparing a prototype of a primary bobbin (2) to which a lead wire is coupled, a primary coil (20) is wound on the outer surface of the prototype, and the winding part is wrapped around an outer case to manufacture a primary bobbin (2).

After preparing a prototype of a secondary bobbin (4) with a lead wire connected in Fig. 1b, a secondary coil (40) is wound on the outer surface of the prototype to produce a secondary bobbin (4).

In Fig. 1c, a bobbin module is assembled by joining a primary bobbin (2) to a hole of a secondary bobbin (4) with a large volume.

Next, the appearance of the bobbin module, which has been pre-assembled using an injection (molding) molding method, is molded to fit the final product. The injection material is not particularly limited as long as it is a plastic-based insulator, but PET (polyethylene terephthalate), PBT (polybutylene terephthalate), or LCP (liquid crystal polymer) can be used.

At this time, when forming the molding part (10), a side flange (12) is formed to provide a heat dissipation structure. Then, a core (6) in the shape of the letter “” is mounted, the middle leg of the core (6) is inserted into the central hole of the bobbin module, and the remaining legs on both sides extend downward along the outer side (14) of the molding part (10) so that their lower ends come into contact with one side of the side flange (12). A flat core (8) is assembled on the opposite side where the core (6) is mounted. The flat core (8) is of the “I” type. That is, the core applied to the transformer (1) of the present invention is an “EI” type core. Both sides of the upper surface of the flat core (8) come into contact with the other surface of the side flange (12).

Fig. 2a is a perspective view of the upper part for explaining the heat dissipation structure of the transformer (1) of the present invention, and Fig. 2b is a cross-sectional view taken along the AA portion after assembly is completed in Fig. 2a. The difference from the structure of Fig. 1c is that the upper and lower parts of the cores are swapped, that is, the flat core (8) is mounted on the upper part of the transformer (1), and the core (6) is mounted on the lower part. In this case, the side flange (12) is naturally formed on the upper part of the transformer (1) for heat dissipation.

The molding part (10) provides a guide (16) to guide the joining of the core (6) and the flat core (8). The side flange (12) is formed long along the side (14) over the entire length where the core (6) and the flat core (8) are mounted, between the guide (16).

The side flange (12) is composed of a contact portion (120) that extends thinly from the inside to the outside and an extended portion (122) that extends up and down from the outer end of the contact portion (120). That is, the side flange (12) has a shape in which a “T” is laid down at a 90-degree angle. The lower surfaces protruding on both sides of the flat core (8) are in contact with the upper surface of the contact portion (120), and the upper end of the right leg of the core (6) is in contact with the lower surface of the contact portion (120). The area where the core (6) and the flat core (8) are in contact can extend to the inner surface of the extended portion (122). In FIG. 2, a side flange (12) having the same structure is installed on the opposite side, which is not shown. Therefore, heat generated in the core (6) is transferred to the side flange (12) through the upper portions of the right and left legs and through the edges on both sides of the flat core (8) and is dissipated. The heating structure of the present invention is most optimal for a composite coil of the “EI” type, but can also be independently applied to a “” type coil or an “I” type coil.

In Fig. 2b, the “A” area is the space where the primary coil (20) of the primary bobbin (2) is located, and the “” area is the space where the secondary coil (40) of the secondary bobbin (4) is located.

Fig. 2c is a perspective view of the bottom for explaining the heat dissipation structure of the transformer (1) of the present invention, and Fig. 2d is a cross-sectional view cut along the BB portion after assembly is completed in Fig. 2c. The structure of these drawings is completely identical to the structure of Fig. 1c, and the only difference from Figs. 2a and 2b is that the core (6) is mounted on the top of the transformer (1), and the flat core (8) is mounted on the bottom.

Below, the explanation will be based on the structures of Figs. 2c and 2d.

Figure 3 is a drawing conceptually explaining the arrangement structure of the core (6) and the flat core (8) of the present invention to increase the heat dissipation effect in the structure described above.

When the core (6) and the flat core (8) are mounted and face each other, the middle, left and right legs of the core (6) are all designed and manufactured to have a gap (G) with the opposing surface of the flat core (8). In particular, in the case of the core (6), it is easy to control the inductance value by controlling the size of the gap (G) of the middle leg.

Figure 4 is a drawing for specifically explaining the heat dissipation effect of the present invention based on the structure described above.

As shown in the drawing, heat generated at the locations where the left and right legs of the core (6) are located and at both sides of the corresponding flat core (8) is released through the side flange (12). In addition, heat generated at the central portion of the core (6) and the flat core (8) is also transferred and released toward the side where the temperature is lowered due to heat dissipation, so that the heat dissipation effect is very good. Furthermore, heat generated at the middle leg of the core (6) can be transferred to the side flange (12) through the minute gaps formed at the upper and lower portions of the regions (A, B). The above heat dissipation paths (heat communication channels) of the core do not overlap with the spaces (A, B) occupied by the coils, and therefore, according to the present invention, heat duplication can be prevented and the heat dissipation function can be effectively performed.

Meanwhile, the present invention does not cover the secondary coil (40) with an outer case after winding the secondary coil (40) as described above in FIG. 1b. While forming the molding part (10), a partition (110) can be formed between the primary coil (20) and the secondary coil (40) as illustrated in FIG. 5. The space between the primary bobbin (2) and the secondary bobbin (4) can be molded with an insulating material, preferably a material identical to or similar to the bobbin, so that the standard distance can be minimized to 1 mm or less, thereby enabling the compact size to be manufactured. The structure of FIG. 5 is preferably applied in addition to the structures of FIGS. 2 to 4, but may be manufactured as an independent structure in an injection molding process.

Fig. 6 is a top perspective view (Fig. 6a) showing the final assembly of the transformer (1) in Figs. 2c and 2d, and a bottom perspective view (Fig. 6b) looking over it. The side flange (12) is formed at the bottom so as to be adjacent to the flat core (8) located at the bottom.

Finally, Fig. 7 is a top perspective view (Fig. 7a) showing the final assembly of the transformer (1) in Figs. 2a and 2b, and a bottom perspective view (Fig. 7b) looking upside down. The side flange (12) is formed at the top so as to be adjacent to the flat core (8).

Although the preferred embodiments of the present invention have been described above, it is obvious that various changes and modifications are possible for the present invention, and the scope of the rights of the present invention extends to an area identical or equivalent to the claims described below.

Claims (8)

In a transformer, a bobbin module is manufactured by assembling a primary bobbin inside which a primary coil is wound and a secondary bobbin outside which a secondary coil is wound, and then a molding part is injection-molded onto the bobbin module through an injection molding process.
A transformer, wherein the molding part includes a side flange formed on the upper or lower side of the side of the molding part to dissipate heat of the core mounted on the primary bobbin and the secondary bobbin. In paragraph 1,
A transformer wherein the above core includes an E-type core and an I-type core, and the side flange is formed adjacent to the side on which the “I”-type core is mounted. In the second paragraph,
A transformer, wherein one surface of the side flange is in contact with the ends of the left and right legs of the E-type core, and the other surface of the side flange is in contact with the exposed surfaces of the protruding sides of the I-type core. In the third paragraph,
A transformer in which the side flange is formed by a contact portion that extends thinly from the inside to the outside of the transformer and an extended portion that extends briefly upward and downward from the outer end of the contact portion, and in which the contact portion contacts at least the exposed surfaces of the ends of the left and right legs of the E-type core and the protruding sides of the I-type core. In the second paragraph,
A transformer, wherein the ends of the middle leg, left leg and right leg of the E-type core are arranged to form a fine gap (G) with each corresponding surface of the I-type core. In any one of claims 1 to 5,
A transformer in which a barrier wall made of insulating material and having a thickness of 1 mm or less is formed between the primary coil and the secondary coil while forming the above molding part. In a method for manufacturing a transformer, the method comprises: assembling an inner primary bobbin having a primary coil wound therein, and an outer secondary bobbin having a secondary coil wound therein, to produce a bobbin module, and then injection-molding a molding part onto the bobbin module through an injection molding process to complete the bobbin module; the method comprises:
A method for manufacturing a transformer, comprising the steps of forming a molding part to dissipate heat from a core mounted on a primary bobbin and a secondary bobbin, and forming a side flange for heat dissipation in a lengthwise direction of the transformer on the upper or lower side of the side of the molding part. In Article 7,
A method for manufacturing a transformer, wherein the step of forming the side flange includes the step of forming a contact portion that extends thinly from the inside of the transformer toward the outside, and an extended portion that extends briefly upward and downward from the outer end of the contact portion.