Transformer

Abstract

An electroconductive wire is wound so as to surround part of a core that is formed from a magnetic-body-containing material. A base (15) supports the core and a plurality of terminals (16). A shield case (14) is formed from an electroconductive material and is joined to the base (15) so as to accommodate the core. A groove (14e) is formed at a position in the shield case (14) that faces at least the plurality of terminals (16).

Description

transformer

[0001] The present disclosure relates to a transformer as an element mounted on a circuit board.

[0002] Patent Document 1 discloses a transformer having a shielding case that houses a core and conductive wires. The transformer includes a base. The base supports conductive terminals. The conductive terminals have a first portion and a second portion. The first portion is electrically connected to contacts formed on a circuit board. The conductive wires used in the transformer are wound around the second portion. The conductive wires are electrically connected to the second portion by soldering or laser welding, thereby establishing an electrical connection between the conductive wires and the contacts.

[0003] Japanese Patent Application Publication No. 2019-102703

[0004] There is a need to suppress the degradation of transformer performance caused by poor conductivity (first requirement).

[0005] There is a need to suppress the degradation of transformer performance caused by misalignment of the shielding case (second requirement).

[0006] One example embodiment provided by the present disclosure to meet the first requirement is a transformer comprising: a core formed from a material containing a magnetic substance; a conductive wire wound so as to surround a portion of the core; a base supporting the core; a plurality of conductive terminals supported by the base; and a shielding case formed from a conductive material and coupled to the base so as to house the core, wherein grooves are formed on an edge of the shielding case at positions facing at least the plurality of conductive terminals.

[0007] This configuration ensures an appropriate distance between the edge of the shielding case and the conductive terminals at the groove locations, thereby preventing unexpected short circuits between the shielding case and the conductive terminals due to, for example, the adhesion of foreign matter, and thus reducing the degradation of transformer performance caused by poor conductivity.

[0008] One example embodiment provided by the present disclosure to meet the second requirement is a transformer comprising: a core formed from a material containing a magnetic substance; a conductive wire wound so as to surround a portion of the core; a base supporting the core; a conductive terminal supported by the base and around which the conductive wire is wound; a shielding case formed from a conductive material and coupled to the base so as to accommodate the core; and an adhesive portion formed from a conductive adhesive and bonding the conductive terminal and the shielding case together.

[0009] This configuration allows the conductive terminals and the shielding case to be electrically connected without using a soldering process. In addition, an anchoring effect is created between the hardened conductive adhesive and the groove, preventing unexpected displacement of the shielding case due to vibration or impact. This prevents degradation of transformer performance due to displacement of the shielding case.

[0010] 1 is an exploded perspective view illustrating the configuration of a transformer according to an embodiment.

[0023] FIG. 1 illustrates an external view of the transformer of FIG. 1 as viewed from the upper right front direction.

[0024] FIG. 1 illustrates an external view of the transformer of FIG. 1 as viewed from the lower left rear direction.

[0025] FIG. 4 illustrates an external view of the transformer of FIG. 1 as viewed from below.

[0026] FIG. 5 illustrates a cross section taken along line V-V in FIG. 4 as viewed from the direction of the arrow.

[0027] FIG. 6 is a diagram for explaining grooves formed in the shielding case of FIG. 1.

[0028] FIG. 7 illustrates another example of the shape of the grooves formed in the shielding case.

[0029] FIG. 8 illustrates another example of the shape of the grooves formed in the shielding case.

[0030] FIG. 9 is a perspective view illustrating the design of the transformer according to FIGS. 1 to 9.

[0031] FIG. 13 is a front view illustrating the design of the transformer of FIG. 13.

[0032] FIG. 14 is a rear view illustrating the design of the transformer of FIG. 13.

[0033] FIG. 15 is a plan view illustrating the design of the transformer of FIG. 13.

[0034] FIG. 16 is a bottom view illustrating the design of the transformer of FIG. 13.

[0035] FIG. 17 is a left side view illustrating the design of the transformer of FIG. 13.

[0036] FIG. 18 is a right side view illustrating the design of the transformer of FIG. 13.

[0037] FIG. 19 is a perspective view illustrating the design of the transformer according to FIGS. 7 to 9. 14 is a front view illustrating the design of the transformer of FIG. 13 , a rear view illustrating the design of the transformer of FIG. 13 , a plan view illustrating the design of the transformer of FIG. 13 , a bottom view illustrating the design of the transformer of FIG. 13 , a left side view illustrating the design of the transformer of FIG. 13 , and a right side view illustrating the design of the transformer of FIG. 13 .

[0011]

[0023] An example embodiment will be described in detail below with reference to the accompanying drawings. In the accompanying drawings, arrow F indicates the forward direction of the illustrated structure. Arrow B indicates the rearward direction of the illustrated structure. Arrow U indicates the upward direction of the illustrated structure. Arrow D indicates the downward direction of the illustrated structure. Arrow R indicates the rightward direction of the illustrated structure. Arrow L indicates the leftward direction of the illustrated structure. These directional expressions are used for convenience of explanation and do not limit the posture or direction of the illustrated structure in actual use.

[0012] The term "front-rear direction" used in this specification means a direction along the aforementioned front and rear directions. The term "up-down direction" used in this specification means a direction along the aforementioned top and bottom directions. The term "left-right direction" used in this specification means a direction along the aforementioned left and right directions.

[0013] The expression "extending in the front-to-rear direction" used in this specification includes extending at an angle relative to the front-to-rear direction, and means extending at an angle closer to the front-to-rear direction than the up-down and left-to-right directions.

[0014] The expression "extending in the vertical direction" used in this specification includes extending at an angle relative to the vertical direction, and means extending at an angle closer to the vertical direction than the front-rear and left-right directions.

[0015] The expression "extending in the left-right direction" used in this specification includes extending at an angle relative to the left-right direction, and means extending at an angle closer to the left-right direction than the front-rear and up-down directions.

[0016] FIG. 1 is an exploded perspective view illustrating the appearance of a transformer 10 according to an embodiment. FIG. 2 illustrates the appearance of the transformer 10 as viewed from the upper right front direction. FIG. 3 illustrates the appearance of the transformer 10 as viewed from the lower left rear direction. FIG. 4 illustrates the appearance of the transformer 10 as viewed from below. FIG. 5 illustrates a cross section of the transformer 10 as viewed from the direction of the arrow along line V-V in FIG. 4.

[0017] 1 and 5, the transformer 10 includes a core 11 and a conductive wire 12. The core 11 has a hollow portion 11a extending in the front-rear direction. The conductive wire 12 is wound around the core 11 to form a coil.

[0018] The transformer 10 includes a first core 131. The first core 131 is made of a material containing a magnetic substance, such as ferrite.

[0019] The first core 131 has a first inner portion 131a and a first outer portion 131b. The first inner portion 131a extends from the front end of the core 11 into the hollow portion 11a. The first outer portion 131b faces the conductive wires 12 from above and from the left and right.

[0020] The second core 132 has a second inner portion 132a and a second outer portion 132b. The second inner portion 132a extends from the rear end of the core 11 into the hollow portion 11a. The second outer portion 132b faces the conductive wire 12 from above and from the left and right.

[0021] At least one of the first inner portion 131a and the second inner portion 132a and the first outer portion 131b and the second outer portion 132b is preferably bonded with an adhesive.

[0022] 1 to 5 , the transformer 10 includes a shield case 14. The shield case 14 is made of a conductive material. Examples of conductive materials include aluminum and copper. The shield case 14 is provided to suppress electromotive forces that may be generated in the conductive wires 12 due to magnetic fields acting as noise coming from outside the transformer 10. The shield case 14 has a box-like shape that opens downward, thereby surrounding the first core 131 and the second core 132 from the front-rear, top, and left-right directions.

[0023] 2 and 3, the transformer 10 includes a base 15 and a plurality of terminals 16. The base 15 is made of an electrically insulating material. Each of the plurality of terminals 16 is made of a conductive material.

[0024] Each of the plurality of terminals 16 is molded integrally with the base 15. Each of the plurality of terminals 16 has a coil terminal 161 and a mounting terminal 162.

[0025] The conductive wire 12 wound around the core 11 is electrically connected to the coil terminal 161. When the transformer 10 is mounted on a circuit board, the mounting terminal 162 is electrically connected to a circuit element formed on the circuit board, thereby electrically connecting the conductive wire 12 to the circuit element on the circuit board.

[0026] Specifically, after a portion of the conductive wire 12 is wound around the coil terminal 161, the conductive wire 12 is joined to the coil terminal 161. In this embodiment, the joining is performed by laser welding. Instead of laser welding, joining may be performed by TIG welding, fusing, ultrasonic metal joining, or the like. The thermally fused coil terminal 161 and the conductive wire 12 form a welded portion W. The welded portion W is an example of a joined portion. As illustrated in FIGS. 2, 3, and 5, the welded portion W is located at the tip of each coil terminal 161.

[0027] Alternatively, the coil terminals 161 and the conductive wires 12 may be joined by high-temperature soldering to form the joined portions, in which case Sn—Sb or Zn—Al solder is used, which has a melting point higher than the reflow temperature when the transformer 10 is mounted on the circuit board.

[0028] 1, the transformer 10 includes a shield plate 17. The shield plate 17 is made of a conductive material. Preferably, the shield plate 17 is made of the same material as the shield case 14.

[0029] The shield plate 17 has a first portion 17a. As illustrated in Fig. 5, the first portion 17a is disposed so as to face the conductive line 12 in the upward direction. The upward direction is an example of the second direction. When the transformer 10 is mounted on a circuit board, the first portion 17a is disposed between the conductive line 12 and the circuit board.

[0030] 1, 3, and 4, the shield plate 17 extends in the left-right direction. The shield plate 17 has a second portion 17b and a third portion 17c. The second portion 17b extends continuously from the left end of the first portion 17a and is inseparably joined to the left side wall 14a of the shield case 14. The third portion 17c extends continuously from the right end of the first portion 17a and is inseparably joined to the right side wall 14b of the shield case 14.

[0031] The shielding case 14 has a box-like shape that opens downward. Therefore, the shielding case 14 cannot cover the conductor wires 12 from below. However, by providing the shielding plate 17, it is possible to ensure a portion of the transformer 10 where the conductor wires 12 are surrounded from the radially outer side of the core 11. In other words, the shielding plate 17 can suppress electromotive forces that may be generated in the conductor wires 12 due to magnetic fields that act as noise coming from below the transformer 10.

[0032] 2, 3, and 6, a groove 14e is formed in the lower edge of each of the front wall 14c and the rear wall 14d of the shield case 14. The groove 14e is formed in a position facing the multiple terminals 16. The groove 14e extends across the multiple terminals 16.

[0033] This configuration ensures a sufficient vertical distance between the lower edge of the shielding case 14 where the grooves 14e are formed and each terminal 16. This prevents unexpected short circuits between the shielding case 14 and the terminals 16 due to, for example, the adhesion of foreign matter, and therefore prevents performance degradation of the transformer 10 due to poor conductivity.

[0034] In particular, when the conductive wire 12 is joined to the terminal 16 to form the welded portion W, the vertical dimension of the terminal 16 tends to increase. Therefore, the effect of the groove 14e, which allows the vertical distance to be secured between the lower edge of the shielding case 14 and the terminal 16, becomes more pronounced.

[0035] As illustrated in Fig. 6, the transformer 10 includes an adhesive portion 18 (Figs. 1 to 5 show the state before the adhesive portion 18 is formed). The multiple terminals 16 include at least one terminal 16a used for connection to a ground potential. The adhesive portion 18 is formed of a conductive adhesive that bonds the terminal 16a to the shielding case 14. This electrically connects the terminal 16a to the shielding case 14.

[0036] Conductive adhesives are made up of a combination of a base material and a conductive material. Examples of the base material include epoxy, silicone, polyester, etc. Examples of the conductive material include silver, copper, nickel, aluminum, etc.

[0037] The conductive adhesive is preferably cured by heating. When the first core 131 and the second core 132 housed in the shield case 14 are bonded with a thermosetting adhesive, it is preferable to select a material for the conductive adhesive so that the adhesive has similar effect conditions as the thermosetting adhesive.

[0038] This configuration allows the terminals 16a and the shielding case 14 to be electrically connected without using a soldering process. In addition, an anchor effect is created between the hardened conductive adhesive and the grooves 14e, preventing unexpected displacement of the shielding case 14 due to vibration or impact. If a material that is softer than solder after hardening is used for the conductive adhesive, the effect of absorbing vibration and impact applied to the shielding case 14 can be improved.

[0039] When the conductive wires 12 and the terminals 16 are electrically connected by welding or high-temperature soldering, as in this embodiment, the heat associated with welding or high-temperature soldering evaporates the tin or other material plated on the terminals 16a connected to the ground potential, making it difficult for solder paste to adhere to the terminals 16a. Therefore, the advantage of being able to electrically connect the terminals 16a and the shielding case 14 with a conductive adhesive rather than solder paste is significant. Additionally, when the shielding case 14 is made of aluminum, which is difficult to plate, as in this embodiment, the solder paste is less likely to adhere to the shielding case 14. Therefore, the advantage of being able to electrically connect the terminals 16a and the shielding case 14 with a conductive adhesive rather than solder paste is significant.

[0040] 7 and 8 show other examples of the shape of the grooves 14e formed in the shield case 14. In this example, a plurality of grooves 14e are formed so as to correspond one-to-one with each of the plurality of terminals 16. In other words, each of the plurality of grooves 14e faces one corresponding terminal 16 in the up-down direction without spanning across the plurality of terminals 16.

[0041] Even with this configuration, a vertical distance can be secured between the lower edge of the shielding case 14 where the grooves 14e are formed and each terminal 16. This makes it possible to prevent unexpected short circuits between the shielding case 14 and the terminals 16 due to, for example, the adhesion of foreign matter, and therefore to prevent performance degradation of the transformer 10 due to poor conductivity.

[0042] 9, the shape of each of the plurality of grooves 14e corresponds to the shape of the welded portion W. Specifically, the groove 14e has an arc shape corresponding to the circumferential surface of the welded portion W, which has a circular shape when viewed from the front-rear direction of the transformer 10.

[0043] 7 to 9, three grooves 14e are formed side by side in the left-right direction in each of the front wall 14c and the rear wall 14d of the shield case 14. The radius of curvature of the arc of the central groove 14e is larger than the radius of curvature of the arc of the grooves 14e on either side.

[0044] Of the three terminals 16 arranged to face the three grooves 14e illustrated in Fig. 7, the central terminal 16b may have a larger number of conductive wires 12 wound therearound. In this case, as shown by the dashed line in Fig. 9, the dimensions of the welded portion W' for joining more conductive wires 12 to the terminal 16b may be larger than the welded portions W on either side. The reason why the radius of curvature of the arc of the central groove 14e is large is to accommodate such a case. Note that the central groove 14e in the rear side wall 14d may be omitted.

[0045] This configuration ensures an appropriate distance between the lower edge of the shield case 14 where the grooves 14e are formed and each of the welded portions W. This makes it possible to prevent unexpected short circuits between the shield case 14 and the welded portions W due to, for example, the adhesion of foreign matter. Therefore, it is possible to prevent performance degradation of the transformer 10 due to poor conductivity.

[0046] As illustrated in Figure 9, the adhesive portion 18 in this example has a portion that is located within a groove 14e that is formed so as not to span multiple terminals 16 (Figures 7 and 8 illustrate the state before the adhesive portion 18 is formed).

[0047] This configuration prevents the uncured conductive adhesive used to electrically connect terminal 16a, which is connected to the ground potential, to shielding case 14 from unexpectedly entering other grooves 14e and causing an unintended short circuit with other terminals 16. In addition, an anchor effect is created between the cured conductive adhesive and grooves 14e, preventing unexpected displacement of shielding case 14 due to vibration or impact.

[0048] The configurations referred to above are merely examples for facilitating understanding of the present disclosure. Each configuration example can be appropriately modified or combined with other configuration examples within the scope of the present disclosure.

[0049] As illustrated in Fig. 1, a plurality of grooves 15a are formed in the upper part of the base 15. Each groove 15a is configured to accommodate a coil terminal 161. As illustrated in Figs. 6 and 9, the adhesive portion 18 has a portion that is disposed within the groove 15a. This further enhances the anchoring effect of the adhesive portion 18 described above.

[0050] In the configuration illustrated in Figure 9, groove 14e of shield case 14 may be omitted if the conductive adhesive that bonds terminal 16a, which is connected to the ground potential, to shield case 14 can be retained in each groove 15a.

[0051] In each of the above-described embodiments, the shielding case 14 is made of aluminum. In this case, increases in the weight of the transformer 10 and increases in component costs can be suppressed. However, the shielding case 14 may also be made of a conductive material such as copper. In this case, the coil terminals 161 and the conductive wires 12 may be joined by soldering. In this case, the solidified solder fillet corresponds to the above-described welded portion W. The solidified solder fillet is an example of a joined portion.

[0052] The design of the transformer according to the embodiment described with reference to FIGS. 1 to 6 is illustrated in FIGS. 10 to 16. FIG. 10 is a perspective view, FIG. 11 is a front view, FIG. 12 is a rear view, FIG. 13 is a plan view, FIG. 14 is a bottom view, FIG. 15 is a left side view, and FIG. 16 is a right side view.

[0053] The design of the transformer according to the embodiment described with reference to Figures 7 to 9 is illustrated in Figures 17 to 23. Figure 17 is a perspective view, Figure 18 is a front view, Figure 19 is a rear view, Figure 20 is a plan view, Figure 21 is a bottom view, Figure 22 is a left side view, and Figure 23 is a right side view.

[0054] The contents of Japanese Patent Application No. 2023-216670 filed on December 22, 2023 and Japanese Patent Application No. 2023-216671 filed on December 22, 2023 are incorporated by reference as part of this disclosure.

Claims

1. A transformer comprising: a core formed from a material containing a magnetic substance; a conductive wire wound so as to surround a portion of the core; a base supporting the core; a plurality of conductive terminals supported by the base; and a shielding case formed from a conductive material and connected to the base so as to house the core, wherein grooves are formed in the shielding case at least at positions facing the plurality of conductive terminals.

2. The transformer according to claim 1, further comprising an adhesive portion which is formed from a conductive adhesive and bonds at least one of the plurality of conductive terminals to the shielding case, the adhesive portion having a portion disposed within the groove.

3. A transformer as claimed in claim 1 or 2, wherein the conductive wire is joined to at least one of the plurality of conductive terminals to form a joined portion, and the joined portion has a vertical dimension larger than that of the conductive terminal.

4. The transformer according to claim 3, wherein the joined portion is formed by welding the conductive wire and the conductive terminal.

5. The transformer according to claim 3, wherein the joined portion is formed by soldering the conductive wire and the conductive terminal.

6. The transformer according to claim 3, wherein the conductive wire is joined to at least one of the plurality of conductive terminals to form a joined portion, and the shape of the groove corresponds to the shape of the joined portion.

7. The transformer according to claim 2, wherein the shielding case is made of aluminum.

8. A transformer comprising: a core made of a material containing a magnetic substance; a conductive wire wound so as to surround a portion of the core; a base supporting the core; a conductive terminal supported by the base and around which the conductive wire is wound; a shielding case made of a conductive material and connected to the base so as to house the core; and an adhesive portion formed of a conductive adhesive and bonding the conductive terminal and the shielding case together.

9. The transformer according to claim 8, wherein a groove is formed in at least one of said shielding case and said base at a position facing at least said conductive terminal, and said adhesive portion has a portion disposed within said groove.

10. A transformer as claimed in claim 8 or 9, wherein the conductive wire is joined to at least one of the conductive terminals to form a joined portion, and the joined portion has a vertical dimension larger than that of the conductive terminal.

11. The transformer according to claim 10, wherein the joined portion is formed by welding the conductive wire and the conductive terminal.

12. The transformer according to claim 10, wherein the joined portion is formed by soldering the conductive wire and the conductive terminal.

13. The transformer according to claim 9, wherein the conductive wire is joined to the conductive terminal to form a joined portion, and the shape of the groove corresponds to the shape of the joined portion.

14. The transformer according to claim 8, wherein the shielding case is made of aluminum.

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