Transformer module

Abstract

To provide a transformer module capable of reinforcing a bent part of a lead terminal in a transformer without increasing the size of a substrate.SOLUTION: A substrate 50 has an enlarged land 62 in which a third lead terminal 23 and a fourth lead terminal 24 adjacent to each other in a juxtaposition direction and having the same potential are soldered by a solder layer 18 at a bonding part 42. Assuming that a land for soldering one bonding part 42 with the solder layer 18 is a reference land 61, the enlarged land 62 is formed by connecting the reference lands 61 corresponding to the third lead terminal 23 and the fourth lead terminal 24 adjacent to each other in the juxtaposition direction with a connection land 64 in the juxtaposition direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a transformer module. [Background technology]

[0002] The transformer module includes a substrate and a transformer. The transformer has a winding and a plurality of lead terminals electrically connected to the winding. The plurality of lead terminals are arranged in a parallel arrangement direction. Each lead terminal is bent from its base and soldered at its tip to a land on the substrate with a solder layer.

[0003] In a transformer module, the transformer is a relatively large component, so when the transformer module vibrates due to external vibration, the transformer also tends to vibrate. When the transformer vibrates, the curved portions of the lead terminals are prone to stress. For this reason, it is preferable to reinforce the curved portions of the lead terminals in a transformer module. One possible method for reinforcing the curved portions is to join a portion of the solder layer to the curved portions. To join a portion of the solder layer to the curved portions, it is necessary to increase the amount of solder paste applied to the lands. For example, Patent Document 1 discloses a method for increasing the amount of solder paste applied to the lands. In Patent Document 1, a wiring board serving as a substrate includes a land pattern for soldering terminals serving as lead terminals and an auxiliary land pattern provided contiguous to the land pattern. The solder paste applied to the auxiliary land pattern migrates toward the land pattern, thereby increasing the amount of solder paste supplied to the land pattern. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 7-131139 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when auxiliary land patterns are added to a board as in Patent Document 1, the size of the board increases in accordance with the addition of the auxiliary land patterns. [Means for solving the problem]

[0006] A transformer module for solving the above problems comprises: a transformer having a plurality of lead terminals electrically connected to windings, the plurality of lead terminals being arranged in a row on a terminal block; and a substrate on which a plurality of lands to which the lead terminals are soldered are arranged in a row, wherein each of the plurality of lead terminals is bent along the substrate by a curved portion, and a joint portion along the substrate is soldered to the land by a solder layer. The transformer module further comprises: a plurality of lead terminals that are adjacent to each other in the juxtaposition direction and have the same potential, and the lands to which the lead terminals are soldered by the solder layer at the joint portion are provided on the substrate as enlarged lands; and when the land for soldering one of the joint portions with the solder layer is defined as a reference land, the enlarged land is formed by connecting the reference lands in the juxtaposition direction, which are assumed to solder each of the lead terminals of the same potential that are adjacent in the juxtaposition direction, with connection lands in the juxtaposition direction.

[0007] According to this, since the enlarged land is formed by connecting a plurality of reference lands with connection lands, the amount of solder paste that can be applied can be increased by adding connection lands. Furthermore, the more the amount of solder paste is increased, the easier it flows toward the joint, and the more easily the solder paste flows toward the curved portion. As a result, the solder layer is more easily bonded to the curved portion, and the curved portion is more easily reinforced by the solder layer.

[0008] To increase the amount of solder paste, enlarged lands were formed on the board. The enlarged lands are formed by connecting reference lands, which are assumed to have lead terminals of the same potential soldered to them, with connection lands. Since insulation is not required between reference lands to which lead terminals of the same potential are connected, adjacent reference lands can be connected with connection lands. The enlarged lands effectively utilize the space between adjacent reference lands to expand the land area. Therefore, even if the enlarged lands are formed, the land placement area on the board does not expand. As a result, curved sections can be reinforced without increasing the size of the board.

[0009] In a transformer module, a plurality of the reference lands may be arranged in the juxtaposition direction, and among the plurality of the juxtaposed reference lands, the reference land arranged at the end of the juxtaposition direction may have a dimension that expands in a direction away from the other adjacent reference lands in the juxtaposition direction.

[0010] This allows lead terminals other than those with the same potential to be soldered by increasing the amount of solder paste.The reference lands at the ends of the juxtaposition direction are expanded in the direction away from each other in the juxtaposition direction, making it easy to reinforce the curved portion without short-circuiting with adjacent reference lands.

[0011] In the transformer module, the solder layer is preferably bonded to the entire bent portion. This allows the curved portion to be reinforced appropriately. [Effects of the Invention]

[0012] The present invention can reinforce the curved portions of the lead terminals in a transformer without increasing the size of the substrate. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a plan view showing a transformer module according to an embodiment. [Figure 2] FIG. 2 is a side view showing the transformer module. [Figure 3]FIG. 3 is an enlarged view showing the lead terminals and solder layers in the enlarged lands. [Figure 4] FIG. 4 is a plan view showing the lead terminals and solder layers in the enlarged lands. [Figure 5] FIG. 5 is a plan view showing a substrate of a reference example. [Figure 6] FIG. 6 is a plan view showing a transformer module according to another embodiment. [Figure 7] FIG. 7 is a plan view showing a transformer module according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, one embodiment of a transformer module will be described with reference to FIGS. <Transformer module> As shown in FIGS. 1 and 2, the transformer module 10 includes a transformer 11 and a substrate 50 to which the transformer 11 is soldered.

[0015] The transformer 11 includes a bobbin 12, a magnetic core 13 fitted to the outer periphery of the bobbin 12, and a primary winding 14 and a secondary winding 15 wound around the bobbin 12. The bobbin 12 has a flange 12a on one side in the axial direction and a flange 12b on the other side. The primary winding 14 is wound around the flange 12a, and the secondary winding 15 is wound around the flange 12b. The primary winding 14 and the secondary winding 15 have different winding ratios. The magnetic core 13 may be of either an EI type or an EE type. A primary terminal block 16 and a secondary terminal block 17 are formed on the lower side of the bobbin 12. The primary terminal block 16 and the secondary terminal block 17 are each block-shaped with their longitudinal axes extending in the same direction.

[0016] The primary terminal block 16 is provided with five primary lead terminals 20. The five primary lead terminals 20 are arranged in the order of the first lead terminal 21, the second lead terminal 22, the dummy lead terminal 25, the third lead terminal 23, and the fourth lead terminal 24 from one end to the other end in the longitudinal direction of the primary terminal block 16. The first to fourth lead terminals 21 to 24 and the dummy lead terminal 25 are arranged side by side on the primary terminal block 16 at equal intervals in the longitudinal direction of the primary terminal block 16. Therefore, the arrangement direction of the five primary lead terminals 20 coincides with the longitudinal direction of the primary terminal block 16. Therefore, the multiple primary lead terminals 20 are arranged side by side in the arrangement direction.

[0017] The primary lead terminals 20 adjacent to each other in the longitudinal direction of the primary terminal block 16 are spaced apart by an insulating distance. The first to fourth lead terminals 21 to 24 are electrically connected to the primary winding 14. The first to second lead terminals 21 to 22 adjacent to each other in the longitudinal direction of the primary terminal block 16 have the same potential, and the third to fourth lead terminals 23 to 24 adjacent to each other in the longitudinal direction of the primary terminal block 16 have the same potential. Therefore, the transformer 11 included in the transformer module 10 has the first to fourth lead terminals 21 to 24 electrically connected to the primary winding 14, and the first to fourth lead terminals 21 to 24 are arranged in parallel on the primary terminal block 16.

[0018] The secondary terminal block 17 is provided with four secondary lead terminals 30. The four secondary lead terminals 30 are arranged in the order of a first lead terminal 31, a second lead terminal 32, a third lead terminal 33, and a fourth lead terminal 34 from one end to the other end in the longitudinal direction of the secondary terminal block 17. The first lead terminal 31 to the fourth lead terminal 34 are arranged side by side in the longitudinal direction of the secondary terminal block 17. The arrangement direction of the four secondary lead terminals 30 coincides with the longitudinal direction of the secondary terminal block 17 and also coincides with the arrangement direction of the five primary lead terminals 20. Therefore, the multiple secondary lead terminals 30 are arranged side by side in the arrangement direction.

[0019] In the secondary terminal block 17, the first lead terminal 31 and the second lead terminal 32 adjacent to each other in the longitudinal direction of the secondary terminal block 17 have different potentials, and the third lead terminal 33 and the fourth lead terminal 34 adjacent to each other in the longitudinal direction of the secondary terminal block 17 have different potentials. In addition, the second lead terminal 32 and the third lead terminal 33 adjacent to each other in the longitudinal direction of the secondary terminal block 17 have different potentials. Therefore, the transformer 11 included in the transformer module 10 has the first to fourth lead terminals 31 to 34 electrically connected to the secondary winding 15, and the first to fourth lead terminals 31 to 34 are arranged in parallel on the secondary terminal block 17.

[0020] In the transformer 11, for example, when AC input power is input from the first lead terminal 21 and the fourth lead terminal 24 on the primary side to the primary winding 14, an output voltage is generated at the first lead terminal 31 and the third lead terminal 33 on the secondary side. In addition, in the transformer 11, when AC input power is input from the second lead terminal 22 and the third lead terminal 23 on the primary side to the primary winding 14, an output voltage is generated at the second lead terminal 32 and the fourth lead terminal 34 on the secondary side. The input voltage is converted into an output voltage depending on the difference in the turns ratio between the primary winding 14 and the secondary winding 15.

[0021] The primary side lead terminal 20 and the secondary side lead terminal 30 are both formed by bending a thin plate into an L shape. Since the primary side lead terminal 20 and the secondary side lead terminal 30 have the same shape, the same member names and member numbers are given to them.

[0022] As shown in Figures 3 and 4, each of the primary side lead terminal 20 and the secondary side lead terminal 30 integrally includes an extending portion 41 extending in a rectangular plate shape from the primary side terminal block 16 and the secondary side terminal block 17, a joint portion 42 extending in a rectangular plate shape intersecting the extending portion 41, and a curved portion 43 connecting the extending portion 41 and the joint portion 42.

[0023] <Substrate> 1 and 2, the substrate 50 has a first main surface 51 and a second main surface 52 that are opposite to each other in the thickness direction. The substrate 50 also has a plurality of primary lands 60 and a plurality of secondary lands 70 that are provided on the first main surface 51. In a plan view of the transformer module 10 seen in the thickness direction, the primary lands 60 are arranged on the primary terminal block 16 side of the transformer 11, and the secondary lands 70 are arranged on the secondary terminal block 17 side of the transformer 11. In a plan view of the transformer module 10 seen in the thickness direction, the primary lands 60 and the secondary lands 70 are arranged with the transformer 11 sandwiched therebetween.

[0024] The primary lead terminals 20 are soldered to the primary lands 60 by solder layers 18, and the secondary lead terminals 30 are soldered to the secondary lands 70 by solder layers 18. Therefore, the substrate 50 has a plurality of primary lands 60 with the primary lead terminals 20 soldered thereto arranged in a row. The substrate 50 also has a plurality of secondary lands 70 with the secondary lead terminals 30 soldered thereto arranged in a row.

[0025] Each of the multiple primary lands 60 has a rectangular shape. The multiple primary lands 60 are arranged such that their short sides extend in the same direction. The direction in which the short sides of the primary lands 60 extend is defined as the first direction X of the substrate 50. The direction in which the long sides of the primary lands 60 extend is defined as the second direction Y of the substrate 50. The multiple primary lands 60 are arranged side by side in the first direction X of the substrate 50. Therefore, the direction in which the multiple primary lands 60 are arranged side by side coincides with the first direction X of the substrate 50. The primary lands 60 adjacent to each other in the first direction X of the substrate 50 are spaced apart from each other by an insulating distance in the first direction X.

[0026] In the primary side land 60, a land for soldering one joint portion 42 with the solder layer 18 is referred to as a reference land 61. In addition, in the primary side land 60, a land to which two joint portions 42 are soldered is referred to as an enlarged land 62. In addition, three reference lands 61 and enlarged lands 62 are arranged side by side on the substrate 50 from one end side to the other end side in the first direction X of the substrate 50.

[0027] The reference land 61 has an area that allows application of the amount of solder paste required to solder one joint 42 with the solder layer 18. This amount of solder paste is an amount that allows the joint 42 to be joined to the primary land 60 while the solder layer 18 is joined to the entire back and side surfaces of the joint 42.

[0028] The reference land 61 and the enlarged land 62 have the same dimension in the second direction Y. The reference land 61 and the enlarged land 62 have different dimensions in the first direction X. The dimension L1 of the enlarged land 62 in the first direction X is larger than the dimension L2 of the reference land 61 in the first direction X. The dimension L1 of the enlarged land 62 is sufficiently larger than twice the dimension L2 of the reference land 61.

[0029] Here, a substrate 80 of a reference example shown in FIG. 5 will be described. The substrate 80 of the reference example has five reference lands 61 and four reference lands 71 ​​as the primary lands 60 and secondary lands 70. The dimensions of the reference lands 61 and 71 in the first direction X in the reference example are the same as the dimension L2 of the reference lands 61 and 71 in the embodiment. The dimensions of the reference lands 61 and 71 in the second direction Y in the reference example are the same as the dimensions of the reference lands 61 and 71 in the second direction Y in the embodiment. The distance between adjacent reference lands 61 and 71 in the first direction X is also the same as the distance between the reference lands 61 and 71 in the embodiment. In other words, the substrate 80 of the reference example has two reference lands 61 arranged instead of the enlarged land 62.

[0030] As shown in FIGS. 1 and 4 , the enlarged land 62 of the embodiment is located at an end of the substrate 80 in the first direction X and is formed by connecting two adjacent reference lands 61 in the first direction X. Specifically, as shown by the two-dot chain line in FIG. 1 , the enlarged land 62 is formed by connecting two reference lands 61, which are assumed to be soldered to the third lead terminal 23 and the fourth lead terminal 24 adjacent in the juxtaposition direction and have the same potential, with a connection land 64 in the juxtaposition direction. Furthermore, these two reference lands 61 are connected by the connection land 64 over the entire longitudinal direction of the reference lands 61. Therefore, the enlarged land 62 has the same dimensions as the reference land 61 in the second direction Y of the substrate 50, but is sufficiently larger than twice the dimensions of the reference land 61 in the first direction X of the substrate 50. The area of ​​the enlarged land 62 is the sum of the areas of the two reference lands 61 and the connection land 64. Therefore, the area of ​​the enlarged land 62 is sufficiently larger than twice the area of ​​the reference land 61.

[0031] The areas of the enlarged lands 62 and the reference lands 61 refer to the areas of the enlarged lands 62 and the reference lands 61 in a plan view of the first main surface 51 of the substrate 50 seen in the thickness direction. As shown in FIG. 1, for the substrate 50 of the embodiment, the distance in the first direction X between the outer edges of the primary lands 60 located at both ends in the first direction X is defined as a reference distance K1. Also, as shown in FIG. 5, for the substrate 80 of the reference example, the distance in the first direction X between the outer edges of the reference lands 61 located at both ends in the first direction X is defined as a reference distance K2. The reference distance K1 and the reference distance K2 are the same. Therefore, compared to the substrate 80 of the reference example, the substrate 50 of the embodiment has the expanded lands 62 without expanding the area of ​​the region where the primary lands 60 are arranged in the first direction X. The area of ​​the region in the second direction Y is also not expanded.

[0032] 1, each of the multiple secondary lands 70 has a rectangular shape. The multiple secondary lands 70 are all arranged with their short sides aligned to extend in the first direction X. The multiple secondary lands 70 are arranged side by side in the first direction X of the substrate 50. Additionally, the secondary lands 70 adjacent to each other in the first direction X of the substrate 50 are spaced apart from each other by an insulating distance in the first direction X.

[0033] Each of the four secondary lands 70 is a reference land 71 to which one secondary lead terminal 30 is soldered. The primary lands 60 and the secondary lands 70 are arranged at positions facing each other in the second direction Y of the substrate 50. Specifically, at one end in the first direction X, two reference lands 61 and a reference land 71 are arranged facing each other in the second direction Y, and at the other end in the first direction X, an enlarged land 62 and two reference lands 71 ​​are arranged facing each other in the second direction Y. Of the five primary lands 60 arranged side by side in the first direction X, no secondary lands 70 are arranged at positions aligned in the second direction Y with respect to the middle reference land 61.

[0034] <Transformer module> The transformer module 10, which is composed of the transformer 11 configured as above and the substrate 50, will now be described.

[0035] As shown in FIG. 1 , on the primary side of the transformer 11, each of the first lead terminal 21 and the second lead terminal 22 is soldered to a reference land 61 of a primary land 60 by a solder layer 18. Also, on the primary side of the transformer 11, primary lead terminals 20 that are adjacent to each other in the juxtaposition direction of the primary lead terminals 20 and have the same potential are soldered to an enlarged land 62 by a solder layer 18 at a joint 42. Therefore, the transformer module 10 has an enlarged land 62 on the substrate 50, to which a third lead terminal 23 and a fourth lead terminal 24 that are adjacent to each other in the juxtaposition direction of the primary lead terminals 20 and have the same potential are soldered by a solder layer 18 at the joint 42. The dummy lead terminal 25 is joined to the reference land 61 at the center in the juxtaposition direction by a solder layer 18. On the secondary side of the transformer 11, each of the first to fourth lead terminals 31 to 34 is joined to a reference land 71 of a secondary side land 70 by a solder layer 18.

[0036] 2, in each of the soldered primary lead terminals 20, the extension portion 41 extends from the lower surface of the primary terminal block 16 toward the substrate 50. Although not shown, in each of the soldered secondary lead terminals 30, the extension portion 41 extends from the lower surface of the secondary terminal block 17 toward the substrate 50.

[0037] 3, each of the primary lead terminals 20 is bent along the substrate 50 by a bending portion 43, and the joint portion 42 that fits along the substrate 50 is soldered to each primary land 60 by a solder layer 18. Furthermore, although not shown, each of the secondary lead terminals 30 is bent along the substrate 50 by a bending portion 43, and the joint portion 42 that fits along the substrate 50 is soldered to each secondary land 70 by a solder layer 18.

[0038] 3 and 4, the solder layer 18 is bonded to the joint portion 42 over the entire longitudinal direction of the joint portion 42, and is also bonded to the tip surface of the joint portion 42 and the outer surface of the curved portion 43. The solder layer 18 is also bonded to both side surfaces in the lateral direction of the joint portion 42. Thus, the solder layer 18 is bonded to the joint portion 42 so as to surround the joint portion 42.

[0039] In the third lead terminal 23 and the fourth lead terminal 24 soldered to the enlarged land 62, a solder fillet 18a is formed on the solder layer 18, sloping downward so as to widen from the upper edge of the joint portion 42 toward the reference land 61. Therefore, the joint portion 42 is joined to the upper part of the solder layer 18, which is formed to bulge on the enlarged land 62. In the solder layer 18, the solder fillet 18a is sloping downward so as to widen from the upper end of the curved portion 43 toward the enlarged land 62. Therefore, the solder layer 18 is joined to the entire curved portion 43 in the height direction. In other words, the solder layer 18 covers the entire curved portion 43 in the height direction.

[0040] [Operation of the embodiment] The method of soldering the transformer 11 to the substrate 50 will be specifically described as a method of soldering the third lead terminal 23 and the fourth lead terminal 24 to the enlarged land 62, together with its operation.

[0041] First, solder paste is applied to each of the primary land 60 and the secondary land 70. Next, the joint portion 42 of the primary lead terminal 20 is placed on the solder paste applied to the primary land 60, and the joint portion 42 of the secondary lead terminal 30 is placed on the solder paste applied to the secondary land 70.

[0042] 1, the enlarged land 62 is formed by connecting two reference lands 61 with a connection land 64, and therefore the area of ​​the enlarged land 62 is sufficiently larger than twice the area of ​​the reference land 61. This allows for a larger amount of solder paste to be applied to the enlarged land 62. As the amount of solder paste increases, the solder paste tends to flow more easily toward the joint portion 42, and therefore the solder paste tends to flow more easily toward the curved portion 43. As a result, the solder paste bulges along the joint portion 42 and the curved portion 43, and as a result, the solder layer 18 is bonded to the curved portion 43 over the entire height direction.

[0043] [Effects of the embodiment] According to the above embodiment, the following effects can be obtained. (1) In the substrate 50, the enlarged land 62 is formed by connecting two reference lands 61 arranged side by side with a connection land 64. Therefore, the amount of solder paste that can be applied to the enlarged land 62 can be increased compared to when solder paste is applied only to the reference land 61. The third lead terminal 23 and the fourth lead terminal 24, which have the same potential, are soldered to the enlarged land 62 with a solder layer 18. Therefore, the solder layer 18 can be bonded to the curved portions 43 of the third lead terminal 23 and the fourth lead terminal 24. As a result, the curved portions 43, which are prone to stress due to vibration, etc., can be reinforced by the solder layer 18.

[0044] The enlarged land 62 is formed by connecting the reference lands 61, to which the third lead terminal 23 and the fourth lead terminal 24, which have the same potential, are supposed to be soldered, with the connection lands 64. Because the primary lands 60 to which the primary lead terminals 20, which have the same potential, are soldered, do not require insulation, the adjacent primary lands 60 can be connected with the connection lands 64. In other words, the enlarged land 62 effectively utilizes the space between adjacent reference lands 61 to expand the land area. Therefore, even if the enlarged land 62 is formed, the arrangement area of ​​the primary lands 60 on the substrate 50 does not expand in the direction in which the primary lands 60 are arranged side by side. As described above, the curved portion 43 can be reinforced without increasing the size of the substrate 50.

[0045] (2) In the third lead terminal 23 and the fourth lead terminal 24 soldered to the enlarged land 62, the solder layer 18 is joined to the entire height of the curved portion 43 by the solder fillet 18a. This allows the curved portion 43 to be suitably reinforced.

[0046] (3) The transformer 11 has dummy lead terminals 25. The dummy lead terminals 25 are provided on the transformer 11 as primary lead terminals 20. There are five primary lead terminals 20 including the dummy lead terminals 25, and four secondary lead terminals 30. This allows the primary lead terminals 20 and the secondary lead terminals 30 to be clearly distinguished, thereby preventing the primary lead terminals 20 from being soldered to the secondary lands 70.

[0047] (4) The enlarged land 62 is formed by connecting two reference lands 61 with the connecting land 64 over the entire longitudinal direction of the reference lands 61. In other words, the enlarged land 62 is rectangular. For example, compared to when two reference lands 61 are connected by the connecting land 64 only at a portion of their longitudinal direction to form an H-shape, the area of ​​the enlarged land 62 can be made larger. This allows for a sufficient increase in the amount of solder paste that can be applied to the enlarged land 62. Furthermore, compared to when only a portion of the longitudinal direction of the reference lands 61 is connected by the connecting land 64, the fluidity of the applied solder paste is increased, making it easier for the solder paste to flow toward the joint portion 42 and the curved portion 43. As a result, the formed solder layer 18 can suitably reinforce the curved portion 43.

[0048] [Example of change] The above-described embodiment can be modified as follows: Each embodiment and the following modifications can be combined with each other to the extent that no technical contradiction occurs.

[0049] As shown in FIG. 6 , the secondary land 70 may have an extended land 73 on the substrate 50 that is longer in the second direction Y than the reference land 71. The extended land may also be provided on the primary land 60. In this configuration, the amount of solder paste that can be applied to the extended land 73 can be increased compared to the amount of solder paste applied to the reference land 71. Therefore, the solder layer 18 can also be bonded to the curved portion 43 of the primary lead terminal 20 or the secondary lead terminal 30 on the extended land 73. As a result, the curved portion 43, which is prone to stress due to vibration, etc., can be reinforced by the solder layer 18.

[0050] 7, among the multiple secondary-side reference lands 71 ​​arranged side by side in the first direction X, the reference land 71 arranged at the end in the arrangement direction may have a dimension that expands in the direction away from the adjacent reference lands 71 ​​in the arrangement direction. Note that the reference land 61 of the primary-side land 60 may also expand in the arrangement direction.

[0051] This allows lead terminals other than the third lead terminal 23 and the fourth lead terminal 24, which have the same potential, to be soldered with an increased amount of solder paste. Here, the reference land 71 at the end in the juxtaposition direction expands in the direction away from the reference land 71, so there is no short circuit with the adjacent reference land 71. This makes it easy to reinforce the curved portion 43 of the secondary lead terminal 30 joined to the reference land 71.

[0052] In the primary side land 60, the first lead terminal 21 and the second lead terminal 22, which are aligned in the juxtaposition direction and have the same potential, may be soldered to the enlarged land 62. One of the five primary side lead terminals 20 is a dummy lead terminal 25, but instead, this one lead terminal may be a lead terminal that is energized in the same way as the other four lead terminals of the primary side lead terminals 20.

[0053] Regarding the transformer module 10, the number of primary side lead terminals 20 and the number of secondary side lead terminals 30 arranged in the juxtaposition direction may be numbers other than those described in the embodiment. Furthermore, the number of primary side lead terminals 20 or secondary side lead terminals 30 adjacent to each other in the juxtaposition direction and having the same potential may be three or more. Depending on the number of primary side lead terminals 20 or secondary side lead terminals 30 having the same potential, the enlarged lands 62 are formed by connecting the same number of reference lands 61 as the number of primary side lead terminals 20 or secondary side lead terminals 30 via connection lands 64. [Explanation of symbols]

[0054] 10...transformer module, 11...transformer, 14...primary winding, 15...secondary winding, 16...primary terminal block, 17...secondary terminal block, 18...solder layer, 20...primary lead terminal, 30...secondary lead terminal, 42...joint portion, 43...bent portion, 50...substrate, 60...primary land, 61...reference land, 62...enlarged land, 64...connection land, 70...secondary land.

Claims

1. a transformer having a plurality of lead terminals electrically connected to the windings, the plurality of lead terminals being arranged in parallel on a terminal block; a substrate on which a plurality of lands to which the lead terminals are soldered are arranged in parallel, a transformer module in which each of the plurality of lead terminals is bent along the substrate by a bending portion, and a joint portion along the substrate is soldered to the land by a solder layer, a plurality of the lead terminals adjacent to each other in a direction in which the lead terminals are arranged side by side and at the same potential have the lands soldered by the solder layer at the joint portions on the substrate as enlarged lands, When the land for soldering one of the joints with the solder layer is defined as a reference land, A transformer module characterized in that the enlarged lands are formed by connecting the reference lands, which are assumed to be used to solder each of the lead terminals of the same potential that are adjacent in the juxtaposition direction, with connection lands in the juxtaposition direction.

2. 2. The transformer module according to claim 1, wherein a plurality of the reference lands are arranged in parallel in the parallel arrangement direction, and among the plurality of the aligned reference lands, the reference land arranged at the end in the parallel arrangement direction has a dimension that increases in a direction away from the adjacent other reference lands in the parallel arrangement direction.

3. 3. The transformer module according to claim 1, wherein the solder layer is bonded to the entire bent portion.

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