Circuit board

Abstract

This circuit board has a circuit component, a support that supports the circuit component, a trace pattern provided on the support, and a through hole that penetrates through the support from one surface to the surface on the opposite side and accepts a terminal of the circuit component. The circuit board has a solder joint portion, provided inside the through hole, where a solder joint is formed between the terminal and the trace pattern. The circuit board has a first suppressing portion which is provided on the trace pattern, discontinuously surrounds the through hole, and has a lower thermal conductivity than the trace pattern. The circuit board has an insulating portion provided at the outer periphery of the trace pattern and a second suppressing portion which is provided on the trace pattern, is located between the first suppressing portion and the insulating portion, and has a lower thermal conductivity than the trace pattern.

Description

circuit board

[0001] This application claims priority from Japanese Patent Application No. 2024-056609, filed on March 29, 2024, the contents of which are incorporated herein by reference.

[0002] Patent Document 1 discloses a circuit board provided with through holes that penetrate from one side where the circuit components are arranged to the opposite side, into which terminals of the circuit components are inserted and which connect the terminals to the wiring pattern at solder joints. In order to connect the terminals to the wiring pattern at the solder joints, the solder joints need to be heated to a temperature equal to or higher than the melting point of the solder.

[0003] Japanese Patent Application Laid-Open No. 2022-018828

[0004] However, when a thick copper substrate or a heat dissipating material is used for the circuit board, the heat dissipation properties of the board are improved, and during soldering, the heat at the solder joint is dissipated, and the injected solder solidifies while being injected into the through hole.

[0005] The present invention has been made in consideration of the above facts, and aims to provide a circuit board that can prevent the injected solder from solidifying while it is being injected into a through hole.

[0006] In order to achieve the above-mentioned object, a first aspect of the circuit board of the present invention comprises a circuit component having a terminal, a support body having one surface supporting the circuit component and a surface opposite to the one surface, a wiring pattern provided on the support body, a through hole penetrating from the one surface to the opposite surface of the support body to receive the terminal of the circuit component, a solder joint provided within the through hole and soldering the terminal and the wiring pattern, a first suppression portion provided on the wiring pattern, intermittently surrounding the through hole, and having a lower thermal conductivity than the wiring pattern, an insulating portion provided on the outer periphery of the wiring pattern, and a second suppression portion provided on the wiring pattern, located between the first suppression portion and the insulating portion, and having a lower thermal conductivity than the wiring pattern.

[0007] The present invention can prevent the injected solder from solidifying while the solder is being injected into the through-hole.

[0008] FIG. 1 is a cross-sectional view taken along line I-I in FIG. 2. FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1. FIG. 3 is a partial cross-sectional view showing an example of the position of a heat sink provided on a circuit board according to the first embodiment. FIG. 4 is a partial cross-sectional view showing an example of the configuration of a circuit board according to the second embodiment. FIG. 5 is a diagram showing an example of a motor unit including a circuit board according to the third embodiment. FIG. 6 is a partial cross-sectional view of an example of a wiring pattern of a circuit board according to a first modified example. FIG. 7 is a partial cross-sectional view of an example of a wiring pattern of a circuit board according to a second modified example. FIG. 8 is a partial cross-sectional view of an example of a wiring pattern of a circuit board according to a third modified example. FIG. 9 is a partial cross-sectional view of an example of a wiring pattern of a circuit board according to a fourth modified example.

[0009] A circuit board according to an embodiment of the present disclosure will now be described with reference to the drawings. A circuit board 100 according to a first embodiment is shown in FIGS. 1 to 3. In the following description, the Z direction shown in FIG. 1 may be referred to as the height direction of the circuit board 100. The left-right direction in FIG. 2 may be referred to as the X direction, and the X direction may be referred to as the width direction of the circuit board 100. The direction perpendicular to the X and Z directions is referred to as the Y direction. The Z direction may also be referred to as the thickness direction or stacking direction of the circuit board 100. The +X direction may also be referred to as the right direction of the circuit board 100, and the −X direction may also be referred to as the left direction of the circuit board 100. The configuration shown in FIG. 2 may also be referred to as the configuration viewed from above or the configuration viewed in the XY plane. The scope of the present invention is not limited to the following embodiments and may be modified as desired within the scope of the technical concept of the present invention. In the drawings, the scale and number of components may differ from the scale and number of components in the actual configuration to make each component easier to understand. In addition, in the following description, expressions such as up, down, left, right, front, back, horizontal, vertical, etc. may be used, but these expressions are used to make the illustrated configuration easier to understand and do not limit the scope of the present invention.

[0010] [First Embodiment] Fig. 1 is a cross-sectional view showing a part of a circuit board 100 according to a first embodiment. Fig. 2 is a cross-sectional view showing a wiring pattern of the circuit board 100 shown in Fig. 1. Fig. 3 is a partial cross-sectional view showing an example of the position of a heat sink 50 provided on the circuit board 100.

[0011] As shown in FIG. 1 , the circuit board 100 of this embodiment includes a support 10 and a circuit component 12 disposed on the support 10. The circuit component 12 is supported by the support 10. The circuit component 12 is, for example, a drive circuit component for driving a three-phase motor. The circuit component 12 has a terminal 121. The support 10 has one surface (first surface) 10a and a surface 10b opposite the first surface 10a. The surface 10a on which the circuit component 12 is disposed may be referred to as the support surface of the support 10 or the upper surface of the support 10. The surface 10b may be referred to as the lower surface or the opposite surface of the support 10. The circuit component 12 is connected to an external device via a connector (not shown). The circuit board 100 also includes a heat sink 50 ( FIG. 3 ). The heat sink 50 will be described later with reference to FIG. 3 .

[0012] The support body 10 is a multilayer substrate in which an upper layer 12U, a middle layer 12M, and a lower layer 12D are stacked in this order from the support surface 10a to the opposite surface 10b. The middle layer 12M is located between the upper layer 12U and the lower layer 12D. The middle layer 12M includes two insulating layers 13 and one wiring pattern layer 14 disposed between the two insulating layers 13. The wiring pattern layer 14 includes a plurality of wiring patterns 14N1 to 14N3 shown in FIG. 2. The insulating layer 13 has electrical insulation properties. The wiring pattern 14N1 is shown in FIG. 1.

[0013] The support body 10 is formed with through holes 11A, 11B, 11C, 11D, 11E, and 11F that penetrate from the support surface (one surface) 10a of the support body 10 to the opposite surface 10b. The through holes 11A and 11B are formed in the wiring pattern 14N1. Because the through holes 11A and 11B are provided close to each other, the distance (pitch) between the through holes 11A and 11B is small. The through holes 11C and 11D are formed in the wiring pattern 14N2. Because the through holes 11C and 11D are provided close to each other, the pitch between the through holes 11C and 11D is small. The through holes 11E and 11F are formed in the wiring pattern 14N3. Because the through holes 11E and 11F are provided close to each other, the pitch between the through holes 11E and 11F is small. The six through holes 11A to 11F have the same shape. 1 shows the through hole 11B. Below, the through hole 11B and the wiring pattern 14N1 will be described, but the same description can also be applied to the other through holes 11A, 11C to 11F and the wiring patterns 14N2 and 14N3.

[0014] A through conductor 8 extending through the through hole 11B is provided inside the through hole 11B. The through conductor 8 is connected to the wiring pattern 14N1. A terminal 121 of the circuit component 12 is inserted into the through conductor 8. That is, the through hole 11B receives the terminal 121. The terminal 121 and the through conductor 8 are joined by a solder joint 17. Therefore, the terminal 121 of the circuit component 12 is connected to the wiring pattern 14N1 via the solder joint 17 and the through conductor 8. Note that the through conductor 8 may be omitted, and the terminal 121 of the circuit component 12 may be connected to the wiring pattern 14N1 via the solder joint 17.

[0015] As shown in FIG. 2 , six first suppression portions 20 are provided on the wiring pattern 14N1. The six first suppression portions 20 are arranged in an elliptical shape. Gaps S are provided between the six first suppression portions 20. In other words, the six first suppression portions 20 are provided intermittently at predetermined intervals. The six first suppression portions 20 are provided to surround the through holes 11A and 11B. The thermal conductivity of the first suppression portions 20 is lower than the thermal conductivity of the wiring pattern 14N1. The first suppression portions 20 suppress the amount and speed of heat (diffused heat) escaping from the solder joint 17 when the solder joint 17 is formed. The first suppression portions 20 are, for example, cavities (depressions, grooves, holes).

[0016] The wiring pattern 14N1 is also provided with a second suppression portion 25N1. Similar to the first suppression portion 20, the second suppression portion 25N1 suppresses the amount and speed of heat (diffused heat) escaping from the solder joint 17 when the solder joint 17 is formed. The second suppression portion 25N1 is located farther from the through holes 11A and 11B than the first suppression portion 20. The thermal conductivity of the second suppression portion 25N1 is lower than the thermal conductivity of the wiring pattern 14N1. Although the second suppression portion 25N1 is located farther from the through holes 11A and 11B than the first suppression portion 20, it is located in a position that can suppress the diffusion of heat from the solder joint 17.

[0017] The wiring pattern 14N1 is made of a material with relatively high thermal conductivity, such as copper. When molten solder is poured into the through conductor 8 to form the solder joint 17, heat from the solder joint 17 (solder heat) diffuses throughout the support 10 via the wiring pattern 14N1. This thermal diffusion may remove heat from the solder and adversely affect the formation of the solder joint 17 (e.g., the solder solidifies before the solder joint 17 is formed). Therefore, it is desirable to suppress the diffusion of heat from the solder joint 17 to the support 10. In this embodiment, the first suppression portion 20 and the second suppression portion 25N1 are provided to suppress the diffusion of heat. The material (including air) constituting the second suppression portion 25N1 may be the same as or different from that of the first suppression portion 20. In this embodiment, the first suppression portion 20 and the second suppression portion 25N1 are each cavities (holes, depressions, or grooves). In other words, the material constituting the first suppression unit 20 and the second suppression unit 25N1 is air. Air exists in the cavity, and air has a lower thermal conductivity (i.e., a higher thermal resistance) than the wiring pattern 14N1. Therefore, the first suppression unit 20 and the second suppression unit 25N1 can suppress the heat of the solder joint 17, which has a temperature equal to or higher than the melting point of the solder, from diffusing through the wiring pattern 14N1. In other words, the temperature of the solder joint 17 can be prevented from dropping below the melting point of the solder.

[0018] 1, the first suppression portion 20 and the second suppression portion 25N1 are also formed in the upper layer 12U. In the embodiment of FIG. 1, the first suppression portion 20 and the second suppression portion 25N1 are not formed in the lower layer 12D.

[0019] As shown in FIG. 2 , the circuit board 100 includes three wiring patterns 14N1-14N3 and insulating portions 9, 9a, and 9b that insulate the three wiring patterns 14N1-14N3. In other words, the wiring patterns 14 are provided in three phases, sandwiched between the insulating portions 9, 9a, and 9b. The insulating portion 9 is a linear insulating portion extending in the X direction. The insulating portion 9a extends a predetermined distance in the Y direction from a predetermined portion 9M1 of the insulating portion 9 and then branches in the Y and X directions. The predetermined portion 9M1 may also be referred to as the starting point of the insulating portion 9a. A bent portion bent at a right angle is formed by the insulating portion 9 near the predetermined portion 9M1 and the insulating portion 9a near the predetermined position 9M1. Since the insulating portion 9a is made of the same material as the insulating portion 9 and is continuous with the insulating portion 9, the bent portion may also be referred to as a bent portion of the insulating portion 9. The insulating portion 9b extends a predetermined distance in the Y direction from a predetermined portion 9M2 of the insulating portion 9, and then branches in the Y direction and the X direction. The predetermined portion 9M2 may be referred to as the starting point of the insulating portion 9b. A bent portion is formed by the insulating portion 9 near the predetermined portion 9M2 and the insulating portion 9b near the predetermined portion 9M2. This bent portion may also be referred to as the bent portion of the insulating portion 9. The three wiring patterns 14N1 to 14N3 are, for example, wiring patterns for supplying power to each phase of a three-phase motor. In FIG. 2, the wiring pattern 14N1 is located on the right side, the wiring pattern 14N3 is located on the left side, and the wiring pattern 14N2 is located between the wiring patterns 14N1 and 14N3. The insulating portion 9a extends between the wiring patterns 14N1 and 14N2, and the insulating portion 9b extends between the wiring patterns 14N2 and 14N3. In FIG. 2 , the wiring pattern 14N1 is surrounded by insulating portions 9 and 9a. That is, the insulating portions 9 and 9a are provided on the outer periphery of the wiring pattern 14N1. The wiring pattern 14N2 is surrounded by insulating portions 9, 9a, and 9b. That is, the insulating portions 9, 9a, and 9b are provided on the outer periphery of the wiring pattern 14N2. The wiring pattern 14N3 is surrounded by insulating portions 9 and 9b. That is, the insulating portions 9 and 9b are provided on the outer periphery of the wiring pattern 14N3. Two through holes 11A and 11B are provided at a predetermined interval along the insulating portion 9 (in the X direction). Two through holes 11C and 11D are provided at a predetermined interval along the insulating portion 9. Two through holes 11E and 11F are provided at a predetermined interval along the insulating portion 9.As described above, the insulating portions 9, 9a, and 9b are continuous and made of the same material, and therefore the insulating portions 9, 9a, and 9b may be collectively referred to as an insulating portion.

[0020] The second suppression portion 25N1 is provided on a side of the through hole 11B different from the side where the distance to the insulating portion 9 is shortest. In this embodiment, the second suppression portion 25N1 contacts the insulating portion 9a. The second suppression portion 25N1 is located between the first suppression portion 20 and the insulating portion 9a. As shown in FIG. 2 , the area of ​​the second suppression portion 25N1 is larger than the area of ​​the first suppression portion 20 when viewed from above. Note that the insulating portions 9, 9a, and 9b can also suppress heat diffusion, so the insulating portions 9, 9a, and 9b can be referred to as additional suppression portions. If the insulating portion 9a and the second suppression portion 25N1 are made of the same material (including air), the second suppression portion 25N1 will be connected to the insulating portion 9a. When the second suppression portion 25N1 is connected to the insulating portion 9a, the combination of the insulating portion 9a and the second suppression portion 25N1 can be said to form a single suppression portion. In this case, the Y-direction dimension of the combination of the insulating portion 9a and the second suppressing portion 25N1 is larger than the Y-direction dimension of the insulating portion 9a.

[0021] As described above, in this embodiment, the second suppression portion 25N1 is in contact with the insulating portion 9a. When the second suppression portion 25N1 and the insulating portion 9a are made of the same material, the second suppression portion 25N1 may be formed by increasing the Y-direction dimension of the insulating portion 9a. When the second suppression portion 25N1 and the insulating portion 9a are not made of the same material, the second suppression portion 25N1 is formed, for example, after the insulating portions 9, 9a, and 9b are formed. More specifically, after the insulating portions 9, 9a, and 9b are formed, the second suppression portion 25N1 is formed by forming a recess with an area larger than the area of ​​the first suppression portion 20 at the position of the second suppression portion 25N1 shown in FIG. 2 so as to be in contact with the insulating portion 9a.

[0022] (Wiring Pattern 14N1) In this embodiment, two through holes 11A and 11B are formed in the wiring pattern 14N1. Note that the number of through holes is not limited to two.

[0023] The wiring pattern 14N1 is formed with six first suppression portions 20. The six first suppression portions 20 are arranged so as to surround the two through holes 11A and 11B, and therefore the six first suppression portions 20 suppress the diffusion of heat from the solder joints 17 of the two through holes 11A and 11B.

[0024] Because the six first suppression units 20 are arranged discontinuously, gaps S are formed between the first suppression units 251. In other words, wiring patterns 14N1 exist between adjacent first suppression units 20. Therefore, some of the heat from the solder joints 17 passes through the gaps S between the six first suppression units 20 (via the wiring patterns 14N1 in the gaps S) and is diffused (arrow T1).

[0025] If the insulating portions 9, 9a, and 9b are cavities (holes, depressions, or grooves), air is present in the insulating portions 9, 9a, and 9b. Therefore, the thermal conductivity of the insulating portions 9, 9a, and 9b, the thermal conductivity of the first suppression portion 20, and the thermal conductivity of the second suppression portion 25N1 are the same. Note that a material that suppresses heat diffusion (e.g., a heat insulating material such as rubber or resin) may be provided inside the cavities of the insulating portions 9, 9a, and 9b. Furthermore, a material that suppresses heat diffusion may also be provided inside the cavities of the first suppression portion 20, and a material that suppresses heat diffusion may also be provided inside the cavities of the second suppression portion 25N1.

[0026] As shown in FIG. 2 , heat that bypasses the six first suppression portions 20 does not diffuse evenly around the two through holes 11A and 11B, but rather diffuses toward the upper right and right of the page in FIG. 2 , as indicated by arrows T1. The regions where the distance between the insulating portions 9 and 9a and the two through holes 11A and 11B is shorter are closer to the heat source (solder joints 17) and have a smaller area for heat dissipation, making it difficult for the temperature to drop. As a result, heat is more likely to diffuse toward the regions where the distance between the insulating portions 9 and 9a and the two through holes 11A and 11B is longer. Because the two through holes 11A and 11B have portions close to the insulating portions 9 and 9a and other portions, the amount of heat diffused per unit time from the entire two through holes 11A and 11B is not uniform in all directions in a plan view.

[0027] As shown in FIG. 2 , the shape of the first suppression unit 20 is rectangular (or approximately rectangular) in top view. The shape of the second suppression unit 25N1 is a parallelogram. Note that the shape of the second suppression unit 25N1 may be a quadrangle other than a parallelogram or a polygon other than a quadrangle in plan view. Furthermore, a portion of the shape of the second suppression unit 25N1 may have a curve in plan view.

[0028] In this embodiment, the second suppression unit 25N1 is arranged to contact the insulating portion 9a to reduce noise on the circuit board 100. When the width of the pattern on the current path changes, the impedance also changes. If the second suppression unit 25N1 is arranged away from the insulating portion 9a, a region with a narrow pattern width is created between the second suppression unit 25N1 and the insulating portion 9a, causing a change in impedance in that region. When the impedance changes, reflection of the current signal may occur, potentially causing waveform distortion. In this embodiment, the second suppression unit 25N1 is arranged in contact with the insulating portion 9a to reduce fluctuations in the pattern width on the current path. Note that the second suppression unit 25N1 may be arranged away from the insulating portion 9a as long as the amount of noise generated does not affect the operation of the circuit board 100.

[0029] As described above, the heat that diffuses through the gaps S of the six first suppression sections 20 diffuses more in the +X and +Y directions compared to the −X and −Y directions when viewed in the XY plane, with the two through holes 11A and 11B as the centers, as shown in FIG.

[0030] The second suppression portion 25N1 is disposed on the side of the two through holes 11A, 11B where heat from the two through holes 11A, 11B is more easily diffused. Specifically, the second suppression portion 25N1 is disposed on the opposite side of the region R1 where the distance between the insulating portion 9 and the two through holes 11A, 11B is short, as viewed from the two through holes 11A, 11B. In other words, the second suppression portion 25N1 is disposed on the opposite side of the starting point 9M1 of the insulating portion 9a. More specifically, the second suppression portion 25N1 is disposed in a region separated by a predetermined distance in the +Y direction from the two through holes 11A, 11B. Note that the second suppression portion 25N1 may be disposed on the +X side of the two through holes 11A, 11B, or on both the +Y and +X sides, as viewed in the XY plane.

[0031] The second suppression portion 25N1 suppresses the heat that diffuses through the gaps S between the six first suppression portions 20 in the wiring pattern 14N1 from further diffusing in the +X direction and the +Y direction.

[0032] (Wiring Pattern 14N2) The wiring pattern 14N2 is formed with two through holes 11C, 11D and six first suppression portions 20 arranged to surround the two through holes 11C, 11D. The six first suppression portions 20 are arranged intermittently in an elliptical shape. The two through holes 11C, 11D are provided at a predetermined interval along the insulating portion 9. The arrangement of the six first suppression portions 20 in the wiring pattern 14N2 is the same as the arrangement of the six first suppression portions 20 in the wiring pattern 14N1. Note that the arrangement of the six first suppression portions 20 does not have to be elliptical. Furthermore, the number of first suppression portions 20 is not limited to six.

[0033] 2, the two through holes 11C and 11D are surrounded by the insulating portions 9, 9a, and 9b in a U-shape in plan view. In other words, in plan view, the through holes 11C and 11D are surrounded by the insulating portions 9, 9a, and 9b in three directions (+X direction, −X direction, +Y direction, −Y direction) of the four directions (+X direction, −X direction, +Y direction, −Y direction).

[0034] Two second suppression portions 25N21 and 25N22 are provided on the wiring pattern 14N2. In a plan view, the second suppression portion 25N21 is provided so as to contact the left insulating portion 9b. In a plan view, the second suppression portion 25N22 is provided so as to contact the right insulating portion 9a. When viewed from the through hole 11C, the second suppression portion 25N21 is located farther away from the first suppression portion 20 that is closest to the through hole 11C in the Y direction. When viewed from the through hole 11D, the second suppression portion 25N22 is located farther away from the first suppression portion 20 that is closest to the through hole 11D in the Y direction. In a plan view, the area of ​​the second suppression portion 25N21 is larger than the area of ​​the first suppression portion 20. Furthermore, in a plan view, the area of ​​the second suppression portion 25N22 is larger than the area of ​​the first suppression portion 20. The second suppression portions 25N21 and 25N22 are formed in regions spaced a predetermined distance in the +Y direction from the two through holes 11C and 11D in a plan view. More specifically, the second suppression portions 25N21 and 25N22 are located on the +Y direction side other than three of the four directions (+X direction, -X direction, +Y direction, -Y direction) in a plan view. In other words, the second suppression portions 25N21 and 25N22 are located on the open side of the U-shape defined by the insulating portions 9, 9a, and 9b when viewed from the through holes 11C and 11D. The first suppression portion 20 and the second suppression portions 25N21 and 25N22 are provided on the upper layer 12U and the middle layer 12M, but not on the lower layer 12D.

[0035] The shape of the second suppression portion 25N21 is a right-angled triangle in plan view, with one of the two sides of the right angle contacting the insulating portion 9b. The shape of the second suppression portion 25N22 is also a right-angled triangle in plan view, with one of the two sides of the right angle contacting the insulating portion 9a. As shown by arrow T2 in FIG. 2 , the area through which heat is transmitted to the wiring pattern 14N2, bypassing the six first suppression portions 20, is gradually narrowed by the hypotenuses of the second suppression portions 25N21 and 25N22. Note that the shape of the second suppression portions 25N21 and 25N22 in plan view may be a triangle other than a right-angled triangle. Furthermore, the shape of the second suppression portions 25N21 and 25N22 in plan view may be a polygon other than a triangle (e.g., a rectangle or a trapezoid). Furthermore, in plan view, the shape of the second suppression portions 25N21 and 25N22 may partially have a curve.

[0036] The second suppression portion 25N21 and the second suppression portion 25N22 suppress the heat that has diffused while bypassing the six first suppression portions 20 in the wiring pattern 14N2 from further diffusing in the +Y direction.

[0037] (Wiring pattern 14N3) The wiring pattern 14N3 has two through holes 11E, 11F and six first suppression portions 20 arranged to surround the two through holes 11E, 11F. The six first suppression portions 20 are arranged intermittently in an elliptical shape. The two through holes 11E, 11F are provided at a predetermined interval along the insulating portion 9. The arrangement of the six first suppression portions 20 in the wiring pattern 14N3 is the same as the arrangement of the six first suppression portions 20 in the wiring pattern 14N1.

[0038] The wiring pattern 14N3 is provided with a second suppression portion 25N3. The second suppression portion 25N3 is located farther away from the two through holes 11E and 11F than the first suppression portion 20. In plan view, the area of ​​the second suppression portion 25N3 is larger than the area of ​​the first suppression portion 20. In plan view, the shape of the second suppression portion 25N3 is trapezoidal. The second suppression portion 25N3 is located between the first suppression portion 20 and the insulating portion 9b. Note that, in plan view, the shape of the second suppression portion 25N3 may be a rectangle other than a trapezoid. Also, in plan view, the shape of the second suppression portion 25N3 may be a polygon other than a rectangle. Also, in plan view, a portion of the shape of the second suppression portion 25N3 may have a curve.

[0039] The second suppression portion 25N3 is disposed so as to contact the insulating portion 9b. The first suppression portion 20 and the second suppression portion 25N3 are provided on the upper layer 12U and the middle layer 12M, but not on the lower layer 12D.

[0040] As indicated by arrow T3, the heat from the solder joint 17 (through holes 11E, 11F) diffuses through the wiring pattern 14N3, bypassing the six first suppression units 20. As shown in FIG. 2 , when viewed from the two through holes 11E, 11F, the heat diffuses more in the −X and +Y directions than in the +X and −Y directions in the XY plane.

[0041] The second suppression portion 25N3 is disposed on the side of the two through holes 11E and 11F where heat from the two through holes 11E and 11F is more easily diffused. Specifically, the second suppression portion 25N3 is disposed on the opposite side of the region R2 where the distance between the insulating portion 9 and the two through holes 11E and 11F is short. That is, the second suppression portion 25N3 is disposed on the opposite side of the starting point 9M2 of the insulating portion 9b from the two through holes 11E and 11F. More specifically, the second suppression portion 25N3 is disposed on the +Y direction side in the XY plane from the two through holes 11E and 11F. Note that the second suppression portion 25N3 may be disposed on the −X direction side in the XY plane from the two through holes 11E and 11F, or on both the −X direction side and the +Y direction side.

[0042] The second suppression portion 25N3 suppresses the heat that diffuses through the gaps S between the six first suppression portions 20 in the wiring pattern 14N3 from further diffusing in the −X direction and the +Y direction.

[0043] As described above, the first suppression portion 20 and the second suppression portions 25N1, 25N21, 25N22, and 25N3 are provided on the upper layer 12U and the middle layer 12M, but are not provided on the lower layer 12D. Therefore, the first suppression portion 20 and the second suppression portions 25N1, 25N21, 25N22, and 25N3 are visible when the support body 10 is viewed from above in the −Z direction, but are not visible when the support body 10 is viewed from below.

[0044] In this embodiment, for example, the first suppression unit 20 and the second suppression units 25N1, 25N21, 25N22, and 25N3 provided in the upper layer 12U are cavities (holes, depressions, and grooves), and the first suppression unit 20 and the second suppression units 25N1, 25N21, 25N22, and 25N3 provided in the middle layer 12M are also cavities (holes, depressions, and grooves). Note that the configurations of the second suppression units 25N1, 25N21, 25N22, and 25N3 provided in the upper layer 12U do not have to be the same as the configurations of the second suppression units 25N1, 25N21, 25N22, and 25N3 provided in the middle layer 12M. For example, the second suppression portions 25N1, 25N21, 25N22, and 25N3 of the upper layer 12U may be hollow, and the second suppression portions 25N1, 25N21, 25N22, and 25N3 of the middle layer 12M may be composed of a hollow and a heat transfer suppression material accommodated in the hollow. The heat transfer suppression material is made of a material (e.g., rubber or resin) having a lower thermal conductivity than the wiring pattern 14.

[0045] FIG. 3 is a partial cross-sectional view showing an example of the position of a heat sink 50 provided on the circuit board 100 of the first embodiment. As shown in FIG. 3, a heat sink 50 is provided on the support 10 of the circuit board 100 to dissipate heat from the circuit board 100 (heat from the support 10). The heat sink 50 is, for example, a heat sink. The heat sink 50 is located farther from the circuit components 12 as viewed from the through holes 11A and 11B. When the circuit components 12 perform a predetermined operation, they generate heat. The heat sink 50 is provided to dissipate the heat. FIG. 3 shows the second suppression portion 25N1 and the insulating portion 9a formed on the wiring pattern 14N1. The second suppression portion 25N1 and the insulating portion 9a formed on the upper layer 12U are also shown. The heat sink 50 is located farther from the second suppression portion 25N1 and the insulating portion 9a as viewed from the through holes 11A and 11B. In FIG. 3, an arrow T extending in the Y direction indicates heat transferred in the Y direction from the through holes 11A and 11B.

[0046] As described above, when viewed from through holes 11A and 11B, heat sink 50 is positioned farther than second suppression portion 25N1 and insulating portion 9a. In other words, second suppression portion 25N1 and insulating portion 9a are located between through holes 11A and 11B and heat sink 50. This makes it possible to suppress (prevent) the solder heat from being dissipated from heat sink 50 before second suppression portion 25N1 (and insulating portion 9a) suppress the diffusion of the solder heat.

[0047] The heat sink 50 may be disposed above the wiring pattern 14N2 in a top view. When the heat sink 50 is disposed above the wiring pattern 14N2, the heat sink 50 is disposed farther from the second suppression portions 25N21 and 25N2 in a top view from the through holes 11C and 11D. The heat sink 50 may also be disposed above the wiring pattern 14N3 in a top view. When the heat sink 50 is disposed above the wiring pattern 14N3, the heat sink 50 is disposed farther from the second suppression portion 25N3 in a top view from the through holes 11E and 11F. The number of heat sinks 50 provided on the support 10 is not limited to one.

[0048] When the circuit board 100 is manufactured, solder is injected into each of the through holes 11A to 11F from the lower surface 10b of the support body 10 toward the upper surface 10a.

[0049] As described above, because solder is injected into the through-hole 11B from the lower surface 10b toward the upper surface 10a, the temperature of the solder located in the lower layer 12D, which is close to the solder injection position, is high. Even if the solder heat diffuses, the injected solder is unlikely to solidify in the lower layer 12D. However, in the middle layer 12M and upper layer 12U, which are farther from the solder injection position, the temperature of the solder tends to be lower. If the heat further diffuses through the middle layer 12M and upper layer 12U, the injected solder is likely to solidify. Therefore, in this embodiment, to prevent the injected solder from solidifying, the first suppression unit 20 and the second suppression units 25N1-25N3 are provided in the upper layer 12U and middle layer 12M. In this embodiment, the first suppression unit 20 and the second suppression units 25N1-25N3 are not provided in the lower layer 12D. In the lower layer 12D, it is believed that the heat of the solder injected into the through holes 11A and 11B is maintained during the soldering operation, and therefore, priority is given to heat dissipation throughout the circuit board 100 rather than suppressing heat diffusion from the solder joints 17. The first suppression portion 20 and the second suppression portions 25N1 to 25N3 may also be provided on the lower layer 12D.

[0050] As described above, the first embodiment can prevent the heat from the solder joint 17 from diffusing (i.e., dissipating) through the wiring patterns 14N1 to 14N3, thereby preventing the injected solder from solidifying. Therefore, the first embodiment can efficiently increase and maintain the temperature of the through holes 11A to 11F during the soldering operation, preventing the injected solder from solidifying. In other words, the first embodiment can improve the solder rise.

[0051] The heating time for the solder joints 17 when forming the solder joints 17 in each of the through holes 11A-11F is approximately 30 seconds. During this time, the area where the heat from the solder joints 17 diffuses is the periphery of each of the through holes 11A-11F. Therefore, in this embodiment, the first suppression portion 20 and the second suppression portions 25N1-25N3 are provided around each of the through holes 11A-11F. That is, the shape of only the periphery of each of the through holes 11A-11F, rather than the entire support 10, is designed to suppress the heat from the solder joints 17 from diffusing throughout the entire support 10. This significantly improves solder rise with fewer design changes. The second suppression portion 25N1 may be arranged to contact the insulating portion 9 rather than the insulating portion 9a. The second suppression portion 25N3 may be arranged to contact the insulating portion 9 rather than the insulating portion 9b.

[0052] 4 is a partial cross-sectional view showing an example of the configuration of a circuit board 100A according to a second embodiment. The circuit board 100A according to the second embodiment has substantially the same configuration as the circuit board 100 according to the first embodiment, and therefore the same parts are denoted by the same reference numerals and their description will be omitted, and only the different parts will be described.

[0053] The circuit board 100A includes a support 10A and a circuit component 12 provided on the support 10A. The support 10A includes an upper layer 12U, an intermediate layer 12Ma, and a lower layer 12D. The intermediate layer 12Ma includes multiple insulating layers 13 and multiple wiring pattern layers 14, with the insulating layers 13 and the wiring pattern layers 14 being alternately stacked. Similarly to the first embodiment ( FIG. 2 ), the support 10A includes six through holes 11A-11F and three wiring patterns 14N1-14N3. The intermediate layer 12Ma of the second embodiment is thicker (has a larger dimension in the Z direction) than the intermediate layer 12M of the first embodiment.

[0054] In the second embodiment, when the circuit board 100A is manufactured, solder is injected into each of the through holes 11A-11F so that it extends from the lower surface 10b of the support 10A toward the upper surface 10a. The first suppression portion 20 and the second suppression portion 25N1-25N3 are provided on the upper layer 12U and the intermediate layer 12Ma. The first suppression portion 20 and the second suppression portion 25N1-25N3 may also be provided on the lower layer 12D. Even when the intermediate layer 12Ma is thick as in this embodiment, the first suppression portion 20 and the second suppression portion 25N1-25N3 can suppress the diffusion (heat transfer) of heat from the solder joint 17 through the wiring patterns 14N1-14N3. As a result, the solder injected into the through holes 11A-11F can be prevented from solidifying during the soldering operation. In other words, even for circuit board 100A with a large Z-direction dimension, the temperature of through holes 11A to 11F can be efficiently increased and maintained during the soldering operation, and the injected solder can be prevented from solidifying.

[0055] Third Embodiment FIG. 5 is a diagram illustrating an example of a motor unit 200 equipped with a circuit board according to a third embodiment. The motor unit 200 illustrated in FIG. 5 includes a housing 200A and a motor 201. The motor 201 is accommodated in the housing 200A. The motor 201 of this embodiment includes, for example, the circuit board 100 of the first embodiment described above as a motor-driving circuit board 202. The circuit components 12 on the circuit board 202 (circuit board 100) are drive circuit components that drive the motor 201. Note that the circuit board 100A of the second embodiment described above may be used as the motor-driving circuit board 202, or a circuit board including the configurations of Modifications 1 to 4 described below may be used. The motor unit 200 is used as a device for generating rotational force in various devices and equipment, such as automobiles, robots, home appliances, computing devices, and medical devices.

[0056] As shown in Fig. 5, the motor 201 in this embodiment includes a shaft 205, a rotor 204, a stator 203, and a circuit board 202. The shaft 205 is fixed to a housing 200A. The rotor 204 is a rotating body that is supported so as to be rotatable about a central axis J. A bearing (not shown) is provided between the rotor 204 and the shaft 205. The stator 203 is fixed to the housing 200A inside the housing 200A and surrounds the outer circumferential surface of the rotor 204. The stator 203 generates an electromagnetic force for rotating the rotor 204. The stator 203 includes a stator core 203a and a coil 203b.

[0057] The circuit board 202 is fixed to the shaft 205 .

[0058] When circuit board 100 is used as circuit board 202 for driving the motor, circuit board 100 is made smaller by narrowing the pitch of through holes 11A to 11F, so the area occupied by circuit board 202 within housing 200A is reduced. As a result, it is possible to achieve a reduction in the overall size and weight of motor unit 200.

[0059] Incidentally, even when the circuit board 100A or a circuit board including the configuration of any of the modifications 1 to 4 is used as the motor drive circuit board 202, the motor unit 200 can be made smaller and lighter.

[0060] [Modifications] Modifications of the first embodiment will be described below with reference to Figures 6 to 9. Figure 5 shows a first modification, Figure 6 shows a second modification, Figure 7 shows a third modification, and Figure 8 shows a fourth modification. The vertical cross-sectional structure of the support body 10 of each modification is substantially the same as that of the first embodiment (Figure 1). Differences from the first embodiment will be described below with reference to Figures 5 to 9 (horizontal cross-sectional views). The same parts as those in the first embodiment will be assigned the same reference numerals and their description will be omitted.

[0061] (First Modification) FIG. 6 is a partial cross-sectional view of a circuit board 100 according to a first modification.

[0062] 2, in the first embodiment, the second suppression portions 25N21 and 25N22 in the wiring pattern 14N2 are each triangular in plan view. The triangle of the second suppression portion 25N21 and the triangle of the second suppression portion 25N22 are bilaterally symmetrical with respect to the arrow T2.

[0063] In contrast, the second suppression unit 25L1 is rectangular in plan view, and the second suppression unit 25L2 is trapezoidal in plan view. The second suppression unit 25L1 and the second suppression unit 25L2 are not symmetrical with respect to the arrow T2. Note that the arrow T2 in Fig. 6 points in the same direction as the arrow T2 in Fig. 2, and does not indicate the thermal diffusion direction in the modified example of Fig. 6.

[0064] One of the short sides of the rectangle of the second suppression portion 25L1 contacts the insulating portion 9b. One of the legs (sides) of the trapezoid of the second suppression portion 25L2 contacts the insulating portion 9a. The other leg of the trapezoid is inclined. Heat that diffuses through the gaps S between the six first suppression portions 20 in the wiring pattern 14N2 is transmitted slightly to the left in FIG. 6 by the inclined leg of the trapezoid of the second suppression portion 25L2.

[0065] In the first modification, the two second suppression units 25L1 and 25L2 provided on the wiring pattern 14N2 are asymmetrical in a plan view, thereby changing the direction of heat diffusion through the wiring pattern 14N2. In particular, as shown in FIG. 6 , the wiring pattern 14N2 located on the +Y direction side of the two second suppression units 25L1 and 25L2 is asymmetrical, so the ease of heat diffusion differs between the left and right sides. In this case, changing the direction of heat diffusion using the two second suppression units 25L1 and 25L2 can further suppress heat diffusion. The positions and shapes of the two second suppression units 25L1 and 25L2 may be designed taking into account factors that affect heat diffusion, such as the position of the heat sink 50 in the first embodiment, in addition to the pattern shape of the wiring pattern 14N2 described above. Furthermore, the design may also take into account fluctuations in the impedance of the wiring pattern 14N2, in addition to suppressing the diffusion of soldering heat.

[0066] (Second Modification) FIG. 7 is a partial cross-sectional view of an example of a wiring pattern on a circuit board 100 according to a second modification.

[0067] 2, the shape of the second suppression portion 25N1 of the wiring pattern 14N1 is a parallelogram in top view. Also, in the first embodiment, the second suppression portion 25N1 is in contact with the insulating portion 9a.

[0068] 7, the second suppression portion 25M11 of the wiring pattern 14N1 has a rectangular shape that is elongated in the X direction in top view. The thermal conductivity of the second suppression portion 25M11 is lower than that of the wiring pattern 14N1. The second suppression portion 25M11 is not in contact with the insulating portions 9 and 9a.

[0069] In the second modified example, the wiring pattern 14N1 is also provided with a third suppression portion 25M12. The third suppression portion 25M12 has a lower thermal conductivity than the wiring pattern 14N1. The third suppression portion 25M12 has a rectangular shape that is longer in the Y direction in a plan view. The third suppression portion 25M12 is in contact with the second suppression portion 25M11. More specifically, one short side of the third suppression portion 25M12 is in contact with one long side of the second suppression portion 25M11. When the second suppression portion 25M11 is hollow and the third suppression portion 25M12 is also hollow, the third suppression portion 25M12 communicates with the second suppression portion 25M11 and extends from the second suppression portion 25M11 in the −Y direction.

[0070] 2, the wiring pattern 14N2 is provided with two second suppression portions 25N21 and 25N22. The second suppression portions 25N21 and 25N22 are triangular in plan view. The second suppression portions 25N21 and 25N22 are in contact with the insulating portions 9a and 9b.

[0071] In contrast, in the second modified example, one second suppression portion 25M2 is provided on the wiring pattern 14N2. The shape of the second suppression portion 25M2 is a rectangle elongated in the X direction in a plan view. The second suppression portion 25M2 is, for example, a recess. The second suppression portion 25M2 does not contact the insulating portions 9a and 9b.

[0072] 2, the second suppression portion 25N3 of the wiring pattern 14N3 has a trapezoidal shape in a plan view, and is in contact with the insulating portion 9b.

[0073] 7, the second suppression portion 25M31 of the wiring pattern 14N3 has a rectangular shape that is long in the X direction in top view. The second suppression portion 25M31 does not contact the insulating portion 9b.

[0074] In the second modified example, the wiring pattern 14N3 is also provided with a third suppression portion 25M32. The third suppression portion 25M32 has a lower thermal conductivity than the wiring pattern 14N3. The third suppression portion 25M32 has a rectangular shape that is longer in the Y direction in a plan view. The third suppression portion 25M32 is in contact with the second suppression portion 25M31. More specifically, one short side of the third suppression portion 25M32 is in contact with one long side of the second suppression portion 25M31. When the second suppression portion 25M31 is hollow and the third suppression portion 25M32 is also hollow, the third suppression portion 25M32 communicates with the second suppression portion 25M31 and extends from the second suppression portion 25M31 in the −Y direction.

[0075] The combined shape of the second suppression portion 25M11 and the third suppression portion 25M12 is L-shaped in a plan view. Because one longitudinal end of the second suppression portion 25M11 and one longitudinal end of the third suppression portion 25M12 are in contact with each other, there is no gap between the second suppression portion 25M11 and the third suppression portion 25M12. Because there is no gap between the second suppression portion 25M11 and the third suppression portion 25M12, heat does not diffuse between the second suppression portion 25M11 and the third suppression portion 25M12. In addition, in FIG. 7 , the other longitudinal end of the second suppression portion 25M11 (the end not in contact with the third suppression portion 25M12) is spaced a predetermined distance from the insulating portion 9a, and the other longitudinal end of the third suppression portion 25M12 (the end not in contact with the third suppression portion 25M11) is spaced a predetermined distance from the insulating portion 9a. In this case, heat from the through holes 11A and 11B diffuses along the path indicated by arrow T5. Therefore, the amount and speed of heat diffusion can be adjusted by appropriately changing the longitudinal dimensions of the second suppression portion 25M11 and the third suppression portion 25M12. In other words, the amount and speed of heat diffusion can be adjusted by appropriately changing the size of the predetermined distance. This facilitates the design of the second suppression portion 25M11 and the third suppression portion 25M12. Similarly, the combined shape of the second suppression portion 25M31 and the third suppression portion 25M32 is L-shaped in plan view. Because one longitudinal end of the second suppression portion 25M31 and one longitudinal end of the third suppression portion 25M32 are in contact with each other, there is no gap between the second suppression portion 25M31 and the third suppression portion 25M32. 7, the second suppression portion 25M31 is spaced a predetermined distance from the insulating portion 9b, and the other longitudinal end of the third suppression portion 25M32 (the end not in contact with the third suppression portion 25M31) is spaced a predetermined distance from the insulating portion 9. Arrow T6 indicates a path along which heat diffuses in the wiring pattern 14N3. Also, in FIG. 7, the second suppression portion 25M2 is spaced a predetermined distance from the insulating portions 9a and 9b, and arrow T7 indicates a path along which heat diffuses in the wiring pattern 14N2. The second modification can simplify the design while suppressing a decrease in the temperature of the solder injected into the solder joint 17 (the amount and speed of heat diffusion can be adjusted simply by changing the longitudinal dimensions of the second suppression portions 25M11, 25M31, and 25M2 and the third suppression portions 25M12 and 25M32).

[0076] 8 is a partial cross-sectional view of an example of a wiring pattern of the circuit board 100 of the third modified example. The third modified example is a modification of the second modified example. In the following description, differences from the second modified example will be explained, and the same parts as those of the second modified example will be assigned the same reference numerals and their explanation will be omitted.

[0077] The wiring pattern 14N1 of the third modification includes a second suppression portion 25P1 instead of the second suppression portion 25M11 and the third suppression portion 25M12 of the second modification. In a plan view, the second suppression portion 25P1 has a rectangular shape that is long in the Y direction. One short side of the rectangle is in contact with the insulating portion 9. As shown in FIG. 8 , no suppression portion that prevents heat diffusion is provided in the region from the second suppression portion 25P1 to the insulating portion 9a when viewed in the Y direction. Therefore, heat diffuses between the second suppression portion 25P1 and the insulating portion 9a in the direction of arrow T8, and the width of the path through which heat diffuses is determined by the longitudinal size of the second suppression portion 25P1.

[0078] The wiring pattern 14N3 of the third modification includes a second suppression portion 25P3 instead of the second suppression portion 25M31 and the third suppression portion 25M32 of the second modification. In plan view, the second suppression portion 25P3 has a rectangular shape elongated in the Y direction. One short side of the rectangle is in contact with the insulating portion 9. As shown in FIG. 8 , no suppression portion that prevents heat diffusion is provided in the region from the second suppression portion 25P3 to the insulating portion 9b when viewed in the Y direction. Therefore, heat diffuses between the second suppression portion 25P3 and the insulating portion 9b, and the width of the path through which heat diffuses is determined by the longitudinal size of the second suppression portion 25P3. The third modification also simplifies design while suppressing a decrease in the temperature of the solder injected into the solder joint 17 (the amount and speed of heat diffusion can be adjusted simply by changing the longitudinal size of the second suppression portions 25P1, 25M2, and 25P3).

[0079] 9 is a partial cross-sectional view of an example of a wiring pattern on a circuit board according to a fourth modification. The fourth modification is a modification of the third modification. In the following description, differences from the third modification will be explained, and the same parts as those in the third modification will be assigned the same reference numerals and will not be explained again.

[0080] The wiring pattern 14N1 of the fourth modification example is provided with a third suppression portion 25P12 in addition to the second suppression portion 25P1. The third suppression portion 25P12 is provided at a position farther from the through hole 11B than the second suppression portion 25P1. The thermal conductivity of the third suppression portion 25P12 is lower than the thermal conductivity of the wiring pattern 14N1. The third suppression portion 25P12 can suppress heat from diffusing away from the second suppression portion 25P1. The third suppression portion 25P12 is, for example, a cavity (a depression or a groove).

[0081] The wiring pattern 14N2 of the fourth modification example is provided with a third suppression portion 25P22 in addition to the second suppression portion 25M2. The third suppression portion 25P22 is provided at a position farther from the through hole 11D than the second suppression portion 25M2. The thermal conductivity of the third suppression portion 25P22 is lower than the thermal conductivity of the wiring pattern 14N2. The third suppression portion 25P22 can suppress heat from diffusing away from the second suppression portion 25M2. The third suppression portion 25P22 is, for example, a cavity (a depression or a groove).

[0082] The wiring pattern 14N3 of the fourth modification includes a third suppression portion 25P32 in addition to the second suppression portion 25P3. The third suppression portion 25P32 is located farther from the through hole 11E than the second suppression portion 25P3. The thermal conductivity of the third suppression portion 25P32 is lower than that of the wiring pattern 14N3. The third suppression portion 25P32 can suppress heat from diffusing around the second suppression portion 25P3. The third suppression portion 25P32 is, for example, a cavity (a recess or a groove). Because the fourth modification includes the third suppression portions 25P12, 25P22, and 25P32, greater suppression of heat diffusion can be achieved compared to the third modification.

[0083] (Other Modifications) The above-described embodiments and modifications may be combined as appropriate within a range that does not cause inconsistencies. Furthermore, the third suppression portion (second modification and fourth modification) is, for example, a cavity (hole, depression, groove), but the technology of the present disclosure is not limited to this. For example, the third suppression portion may be made of a material (e.g., rubber or resin) that has a lower thermal conductivity than the wiring pattern. When the first suppression portion, second suppression portion, and third suppression portion (second modification and fourth modification) are made of rubber or resin, and the insulating portion 9 is a cavity (hole, depression, groove), the thermal conductivity of each portion has the following magnitude relationship: wiring pattern > first suppression portion, second suppression portion, third suppression portion > insulating portion

[0084] The circuit board of the present disclosure can have the following configuration.

[0085] (Configuration 1) A circuit board comprising: a circuit component having a terminal; a support having one surface supporting the circuit component and a surface opposite to the one surface; a wiring pattern provided on the support; a through hole penetrating from the one surface to the opposite surface of the support and receiving the terminal of the circuit component; a solder joint provided within the through hole and soldering the terminal and the wiring pattern; a first suppression portion provided on the wiring pattern, discontinuously surrounding the through hole and having a lower thermal conductivity than the wiring pattern; an insulating portion provided on the periphery of the wiring pattern; and a second suppression portion provided on the wiring pattern, located between the first suppression portion and the insulating portion, and having a lower thermal conductivity than the wiring pattern.

[0086] (Configuration 2) The circuit board according to configuration 1, wherein the second suppression portion is in contact with the insulating portion.

[0087] (Configuration 3) The circuit board according to configuration 1 or 2, further comprising a third suppression portion located farther from the through hole than the second suppression portion, and the thermal conductivity of the third suppression portion is lower than the thermal conductivity of the wiring pattern.

[0088] (Configuration 4) The circuit board according to any one of configurations 1 to 3, wherein the insulating portion has a bent portion, the first suppression portion is provided in the vicinity of the bent portion, and the amount of heat per unit time diffusing from the through hole to the bent portion is less than the amount of heat per unit time diffusing to portions other than the bent portion.

[0089] (Configuration 5) The circuit board according to configuration 4, wherein the second suppression portion is provided at a position away from the bent portion.

[0090] (Configuration 6) The circuit board according to configuration 3, wherein the third suppression portion is in contact with the second suppression portion.

[0091] (Configuration 7) The circuit board according to any one of configurations 1 to 6, wherein the first suppression portion has a portion located near the insulating portion, and the second suppression portion is disposed on the opposite side of the portion located near the portion.

[0092] (Configuration 8) A circuit board according to any one of configurations 1 to 7, wherein, when viewed from above the one surface, the insulating portion has a portion that surrounds the through hole in a U-shape, and the second suppression portion is located on the open side of the U-shape when viewed from the through hole.

[0093] (Configuration 9) The support is a multilayer substrate in which an upper layer pattern located on one side, at least one middle layer pattern, and a lower layer pattern located on the opposite side are stacked from the one side to the opposite side via an electrically insulating insulating layer, the solder joint is formed by solder injected into the through hole so as to extend from the opposite side to the one side, and the first suppression portion and the second suppression portion are provided on the upper layer pattern and the middle layer pattern, a circuit board described in any of configurations 1 to 8 above.

[0094] (Configuration 10) The circuit board according to configuration 9, wherein the first suppression portion and the second suppression portion are also provided in the lower layer pattern.

[0095] (Configuration 11) The circuit board according to any one of configurations 1 to 10, wherein the circuit component is a drive circuit component that drives a three-phase motor, the wiring pattern is provided for three phases with the insulating section sandwiched therebetween, and the first suppression section and the insulating section / second suppression section are provided in the wiring pattern of each phase.

[0096] (Configuration 12) The circuit board according to any one of the above configurations 1 to 11, wherein the circuit board is provided with a heat sink that dissipates heat from the support body, and the heat sink is positioned farther from the through hole than the second suppression portion.

[0097] (Configuration 13) The circuit board according to any one of claims 1 to 12, wherein at least one of the first suppression portion and the second suppression portion is a cavity.

[0098] (Configuration 14) The circuit board according to configuration 13, wherein the cavity is provided with a material that suppresses heat diffusion.

[0099] (Configuration 15) The circuit board according to any one of configurations 1 to 14, wherein the insulating portion is a cavity.

[0100] (Configuration 16) The circuit board according to any one of configurations 1 to 15, wherein the circuit board has a plurality of the through holes, and the first suppression portion is disposed so as to surround the periphery of the plurality of the through holes.

[0101] (Configuration 17) The circuit board according to any one of configurations 1 to 16, wherein the area of ​​the second suppression portion is larger than the area of ​​the first suppression portion.

[0102] (Configuration 18) The circuit board according to configuration 3, wherein a longitudinal direction of the third suppression portion is different from a longitudinal direction of the second suppression portion.

[0103] (Configuration 19) The circuit board according to configuration 3, wherein the third suppression portion is in contact with the second suppression portion perpendicularly.

[0104] (Configuration 20) A three-phase motor comprising: a rotor; a stator provided so as to surround an outer peripheral surface of the rotor; and the circuit board according to configuration 11.

[0105] 100 Circuit board 9, 9a, 9b Insulating portion 10 Support 12 Circuit component 12U Upper layer 12M Middle layer 12D Lower layer 13 Insulating layer 14 Wiring pattern layer 14N1 to 14N Wiring patterns 11A, 11B, 11C, 11D, 11E, 11F Through hole 20 First suppressing portion 25N1, 25N21, 25N22, 25N3 Second suppressing portion

Claims

1. A circuit board comprising: a circuit component having a terminal; a support having one surface for supporting the circuit component and a surface opposite the one surface; a wiring pattern provided on the support; through holes that penetrate from the one surface to the opposite surface of the support and receive the terminals of the circuit component; a solder joint provided within the through hole and soldering the terminal and the wiring pattern; a first suppression portion provided on the wiring pattern, discontinuously surrounding the through hole and having a lower thermal conductivity than the wiring pattern; an insulating portion provided on the periphery of the wiring pattern; and a second suppression portion provided on the wiring pattern, located between the first suppression portion and the insulating portion, and having a lower thermal conductivity than the wiring pattern.

2. The circuit board according to claim 1, wherein said second suppression portion is in contact with said insulating portion.

3. A circuit board as described in claim 1 or claim 2, wherein the circuit board further has a third suppression portion located farther from the through hole than the second suppression portion, and the thermal conductivity of the third suppression portion is lower than the thermal conductivity of the wiring pattern.

4. A circuit board as described in claim 1 or claim 2, wherein the insulating section has a bent section, the first suppression section is provided in the vicinity of the bent section, and the amount of heat per unit time diffusing from the through hole to the bent section is less than the amount of heat per unit time diffusing to areas other than the bent section.

5. The circuit board according to claim 4, wherein the second suppression portion is provided at a position spaced apart from the bent portion.

6. The circuit board according to claim 3, wherein the third suppression portion is in contact with the second suppression portion.

7. The circuit board according to claim 1 or 2, wherein the first suppression portion has a portion located near the insulating portion, and the second suppression portion is located on the opposite side of the portion located near the portion.

8. A circuit board as described in claim 1 or claim 2, wherein, when viewed from above said one surface, said insulating portion has a portion that surrounds said through hole in a U-shape, and said second suppression portion is located on the open side of said U-shape when viewed from said through hole.

9. The circuit board according to claim 1 or claim 2, wherein the support is a multilayer board in which an upper layer pattern located on one side, at least one middle layer pattern, and a lower layer pattern located on the opposite side are stacked from the one side to the opposite side with an electrically insulating layer interposed therebetween, the solder joint portion is formed by solder injected into the through hole so as to extend from the opposite side to the one side, and the first suppression portion and the second suppression portion are provided on the upper layer pattern and the middle layer pattern.

10. The circuit board according to claim 9, wherein the first suppression portion and the second suppression portion are also provided in the lower layer pattern.

11. A circuit board as described in claim 1 or claim 2, wherein the circuit components are drive circuit components for driving a three-phase motor, the wiring patterns are provided for three phases with the insulating section sandwiched between them, and the first suppression section and the insulating section second suppression section are provided in the wiring patterns of each phase.

12. A circuit board as described in claim 1 or claim 2, wherein the circuit board is provided with a heat sink that dissipates heat from the support, and the heat sink is positioned farther from the through hole than the second suppression portion.

13. The circuit board according to claim 1 or 2, wherein at least one of the first suppression portion and the second suppression portion is a cavity.

14. The circuit board according to claim 13, wherein the cavity is provided with a material that inhibits heat diffusion.

15. The circuit board according to claim 1 or 2, wherein the insulating portion is a cavity.

16. The circuit board according to claim 1 or 2, wherein the circuit board has a plurality of the through holes, and the first suppression portion is arranged so as to surround the periphery of the plurality of the through holes.

17. The circuit board according to claim 1 or 2, wherein the area of ​​the second suppression portion is larger than the area of ​​the first suppression portion.

18. The circuit board according to claim 3, wherein the longitudinal direction of the third suppression portion is different from the longitudinal direction of the second suppression portion.

19. The circuit board according to claim 3, wherein the third suppression portion is in contact with the second suppression portion perpendicularly.

20. A three-phase motor comprising: a rotor; a stator provided so as to surround the outer circumferential surface of the rotor; and the circuit board according to claim 11.

Images