Electronic circuit boards and electronic circuit units

Abstract

To provide an electronic circuit board and electronic circuit unit that facilitates soldering of leaded components and the like. [Solution] The circuit board for electronic circuits comprises a multilayer substrate composed of multiple layers in which insulating layers and conductive layers are alternately laminated. The conductive layer of the multilayer substrate has a circular or elliptical land 3 connected to a through-hole and a conductive member 11 connected via a connecting portion 10 extending radially outward A2 from the outer edge of the land 3. When the two conductive layers sandwiching the insulating layer are viewed in the substrate thickness direction, the connecting portion 10 in one conductive layer is positioned at half the phase of the entire circumference of the land 3, and the connecting portion 10 in the other conductive layer is positioned at the remaining half the phase of the entire circumference of the land 3. The insulating layer is an insulating resin sheet.

Description

Technical Field

[0001] The present invention relates to a printed circuit board for an electronic circuit and an electronic circuit unit that can be applied to, for example, an electromechanical integrated electric actuator in which an actuator body and a control device for controlling the actuator body are modularized, and relates to a technique for facilitating soldering of lead components or the like to the printed circuit board.

Background Art

[0002] As shown in FIGS. 9 and 10, an electronic circuit unit has been proposed in which a lead portion such as a motor bus bar or a lead component is inserted into a through hole 50 connected to a pattern on a substrate, and the lead portion and solder are heated to make an electrical connection (Patent Document 1).

[0003] However, when the pattern on the substrate is a GND or the output portion of the motor, as the current value increases, the cross-sectional area of the pattern also needs to be proportionally increased, and the heat capacity increases, making it difficult to solder. Therefore, a pattern cutting method called a thermal land 51 is adopted. In Patent Document 1, the spoke portion (connecting bar) 52 of the thermal land 51 is gradually shifted in each layer of the substrate. This makes it difficult for heat to radiate to the pattern and facilitates soldering.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] As shown in FIG. 11, for example, an actual four-layer substrate is composed of a copper foil 53 as a pattern, a prepreg 54 that insulates between the first to fourth layers and between the first and second layers, and a core material 55 that insulates between the second and third layers. Generally, copper foil 53 is used with a film thickness of 35 to 105 μm (= 1 to 3 oz), and for high currents, a film thickness of 70 μm (= 2 oz) or more is required. The prepreg 54 has a film thickness of 0.2 mm, and the core material 55 has a film thickness of about 1.0 mm. In addition, in the case of a 6-layer substrate, the core material 55 is sandwiched between the 3rd and 4th layers, or between the 1st and 2nd layers and the 5th and 6th layers.

[0006] As described in Patent Document 1, even if the angle of the spoke portion is gradually changed, the heat does not pass only through the pattern between the layers with the prepreg in between because the prepreg is thin, and the adjacent layers are also heated at the same time, resulting in a low effect of hindering heat dissipation.

[0007] The object of the present invention is to provide an electronic circuit board and an electronic circuit unit that facilitate the soldering of leaded components and the like. [Means for solving the problem]

[0008] The present invention provides an electronic circuit board comprising a multilayer board composed of multiple layers in which insulating layers and conductive layers are alternately laminated, or a double-sided board in which conductive layers are provided on both sides of an insulating layer, wherein the conductive layers of the multilayer board or the double-sided board have circular or elliptical lands connected to through-holes and conductive members connected via connecting portions extending radially outward from the outer edge of the lands, With the two conductive layers sandwiching the insulating layer viewed in the substrate thickness direction, the connecting portion of one conductive layer is positioned at half the phase of the entire circumference of the land, and the connecting portion of the other conductive layer is positioned at the remaining half the phase of the entire circumference of the land.

[0009] In the case of a conductive layer sandwiching an insulating resin sheet such as a prepreg, the thickness of the prepreg is thinner than that of the core material, so heat is easily transferred to adjacent conductive layers. In this configuration, the connecting portion of one of the two conductive layers sandwiching the insulating layer is positioned at half the phase of the entire circumference of the land. Furthermore, the connecting portion of the other conductive layer is positioned at the remaining half of the phase of the entire circumference of the land. As a result, heat transfer between the two conductive layers sandwiching the insulating layer can be suppressed. This suppresses heat transfer to the conductive member during the process of heating and melting the solder applied to the land in a reflow oven, for example, and allows the solder to melt sufficiently. Therefore, it is possible to easily solder motor busbars or leaded components (leaded components, etc.) to the land.

[0010] The insulating layer may be an insulating resin sheet. This insulating resin sheet is, for example, a layer of glass fibers impregnated with resin, and can be bonded to the surface of the core material via a conductive layer.

[0011] The multilayer substrate may be formed by laminating the conductive layers provided on both sides of the insulating resin sheet and an insulating core material in the thickness direction of the substrate. In this case, power lines and general signal lines can be provided in the inner layers of the multilayer substrate, making it possible to secure a large mounting space on the surface of the multilayer substrate.

[0012] The electronic circuit unit of the present invention comprises an electronic circuit board as described above and electronic components supported on the electronic circuit board. In this case, an electronic circuit unit with improved solderability can be constructed, thereby increasing the yield and reducing manufacturing costs compared to conventional structures.

[0013] The electronic circuit unit of the present invention comprises an electronic circuit board as described above and leaded components soldered to the lands. In this case, the leaded components can be easily soldered to the lands, thereby increasing the yield and reducing manufacturing costs compared to conventional structures. [Effects of the Invention]

[0014] The present invention provides an electronic circuit board comprising a multilayer board composed of multiple layers in which insulating layers and conductive layers are alternately laminated, or a double-sided board in which conductive layers are provided on both sides of an insulating layer, wherein the conductive layers of the multilayer board or the double-sided board have circular or elliptical lands connected to through-holes and conductive members connected via connecting portions extending radially outward from the outer edge of the lands, wherein, when the two conductive layers sandwiching the insulating layer are viewed in the thickness direction of the board, the connecting portion of one conductive layer is positioned at half the phase of the entire circumference of the land, and the connecting portion of the other conductive layer is positioned at the remaining half the phase of the entire circumference of the land. As a result, it is possible to realize an electronic circuit board that makes it easier to solder leaded components and the like compared to conventional structures. [Brief explanation of the drawing]

[0015] [Figure 1] This is a longitudinal cross-sectional view of an electronic circuit unit in which electronic components are mounted on an electronic circuit board according to the first embodiment of the present invention. [Figure 2] This diagram shows the arrangement of connecting parts for each conductor layer in the electronic circuit board. [Figure 3A] This figure shows the connection between the first and second layers of the electronic circuit board as viewed in the thickness direction of the board. [Figure 3B] This figure shows the connection between the third and fourth layers of the electronic circuit board as viewed in the thickness direction of the board. [Figure 4] This diagram shows the arrangement of connecting parts for each conductor layer with a changed number of connecting parts in the same electronic circuit board. [Figure 5A] This figure shows the connection between the first and second layers of the electronic circuit board shown in Figure 4, viewed in the thickness direction of the board. [Figure 5B] This figure shows the connection between the third and fourth layers of the electronic circuit board shown in Figure 4, viewed in the thickness direction of the board. [Figure 6] This figure shows the arrangement of connecting portions for each conductive layer in an electronic circuit substrate according to a second embodiment of the present invention. [Figure 7]It is a diagram showing the arrangement of connection parts for each conductor layer in a substrate for an electronic circuit according to a third embodiment of the present invention. [Figure 8] It is a longitudinal sectional view of a substrate for an electronic circuit according to a fourth embodiment of the present invention. [Figure 9] It is a diagram showing the spoke portions of thermal lands in each layer in a conventional electronic circuit unit. [Figure 10] It is a longitudinal sectional view of the same electronic circuit unit. [Figure 11] It is a longitudinal sectional view of a conventional four-layer substrate.

Mode for Carrying Out the Invention

[0016] [First Embodiment] A substrate for an electronic circuit and an electronic circuit unit according to an embodiment of the present invention will be described together with FIGS. 1 to 5B. The substrate for an electronic circuit and the electronic circuit unit can be applied as the control device in, for example, an electromechanical integrated electric actuator in which an actuator body such as a motor and a control device for controlling the actuator body are modularized. However, it is also possible to apply the substrate for an electronic circuit and the electronic circuit unit to uses other than electromechanical integrated electric actuators.

[0017] As shown in FIG. 1, the electronic circuit unit 1 includes a substrate 2 for an electronic circuit, electronic components 4 supported by the substrate 2 for an electronic circuit, and lead components soldered to the lands 3 of the substrate 2 for an electronic circuit. Examples of the electronic components 4 include semiconductors such as ICs and transistors, and examples of the lead components include DIP (Dual In-line Package) components and SIP (Single In-line Package) components in which leads Ld protrude.

[0018] <Substrate for Electronic Circuit> The electronic circuit board 2 in this example is a multilayer board composed of multiple layers in which insulating layers 5 and conductive layers 6 are alternately stacked. In the multilayer board, conductive layers 6,6 provided on both sides of an insulating resin sheet which is the insulating layer 5, and an insulating core material 7 are stacked in the board thickness direction A1. In the example in Figure 1, a 4-layer board is used as the multilayer board, but the number of layers may be increased to 6-layer boards, 8-layer boards, etc., which are not shown. The electronic circuit board 2 is not limited to a multilayer board and can also be applied to double-sided boards, which will be described later.

[0019] The four-layer substrate has copper foil patterns as conductive layers 6 for the first to fourth layers, an insulating resin sheet 5 that insulates between the first and second layers and between the third and fourth layers, a core material 7 that insulates between the second and third layers, and resists 8, 8 that are protective films that protect the surfaces of the first and fourth layers. The insulating resin sheet 5 is a prepreg, which is a layer of glass fibers impregnated with resin, and can be bonded to both sides of the core material 7 via the conductive layers 6.

[0020] <Parameters, etc.> The resist 8 has a thickness of 20-40 μm, the copper foil conductive layer 6 has a thickness of 35-105 μm, the prepreg 5 has a thickness of 0.2 mm, and the core material 7 has a thickness of approximately 1.0 mm. However, these thicknesses are not the only possible thicknesses.

[0021] As shown in Figures 1 and 2, each conductive layer 6 has a circular land 3 (Figure 2) connected to a through-hole 9 and a conductive member 11 connected via a connecting portion 10 extending radially outward A2 from the outer edge of the land 3. In Figure 2, "boundary lines" are provided between the land 3 and the connecting portion 10, and between the connecting portion 10 and the conductive member 11, but these "boundary lines" are imaginary lines to clearly show the positional relationship of each part. The same applies to Figures 3A to 7. As shown in Figure 2, the land 3 is formed in a circular shape when viewed in the thickness direction of the substrate, but it may also be elliptical. As shown in Figures 1 and 2, the through-hole 9 penetrates through the first to fourth layers and has copper foil on its inner wall. The lead Ld of the leaded component is inserted into the through-hole 9, and the electronic component 4 is supported (mounted) on the surface of the four-layer substrate. In this example, the electronic component 4 is electrically connected to the conductor layer 6 in the first layer.

[0022] The conductive member 11 is, for example, an annular electrode 11a or a ground layer 11b. In each layer, the land 3, connecting portion 10, and conductive member 11 are formed by removing unnecessary parts of the copper foil, for example, by etching or exposure. Since the land 3 of each layer is connected to the conductive member 11 via a plurality of connecting portions 10, it is formed as a thermal land that can suppress heat dissipation. The connecting portion 10 is also called a spoke 10.

[0023] Each connecting portion 10 is a straight line extending radially outward A2 from the outer edge of the land 3 and is formed with a constant width dimension W1. The width dimension W1 is set appropriately according to the application, in other words, the magnitude of the current flowing through the connecting portion 10. For example, in applications such as motors where a large current flows, the width dimension W1 of the connecting portion 10 is formed to be relatively wide. In applications where a small current flows, the width dimension W1 of the connecting portion 10 is formed to be relatively narrow.

[0024] <Spoke arrangement, etc.> With the two conductive layers 6, 6 sandwiching the prepreg 5 viewed in the substrate thickness direction A1, the connecting portion 10 in one conductive layer 6 is positioned at half the phase of the entire circumference, and the connecting portion 10 in the other conductive layer 6 is positioned at the remaining half of the phase of the entire circumference.

[0025] Specifically, the first and second conductive layers 6, 6 sandwiching the prepreg 5 are viewed in the substrate thickness direction A1, as shown in Figure 3A. In this case, the spokes 10 of the first layer, shown by solid lines, extend radially in three directions from the outer edge of the land 3 of the first layer, and these spokes 10 are arranged in the phase of the left half of the figure. If the vertical direction of the figure is considered to be 0 o'clock and 6 o'clock, the three spokes 10 are arranged in the phase of the left half to extend sequentially from the outer edge of the land 3 in the directions of 7 o'clock, 9 o'clock, and 11 o'clock.

[0026] The spokes 10 of the second layer, shown by the dotted lines, extend radially in three directions from the outer edge of the land 3 of the second layer, and these spokes 10 are arranged in the phase shown in the right half of the figure. In the phase shown in the right half, the three spokes 10 are arranged to extend sequentially from the outer edge of the land 3 in the directions of 1 o'clock, 3 o'clock, and 5 o'clock. In the case of a four-layer substrate, if the prepreg 5 shown in Figure 1 is made of a transparent material, the spokes 10 of the conductive layers 6,6 of the first and second layers (Figure 2) are visible externally as shown in Figure 3A. As shown in Figure 3B, the spokes 10 of the conductive layers 6,6 of the third and fourth layers are also visible externally.

[0027] As shown in Figure 1, when viewing the third and fourth conductive layers 6, 6 sandwiching the prepreg 5 in the substrate thickness direction A1, as shown in Figures 1 and 3B, the spokes 10 of the third layer extend radially in three directions from the outer edge of the land 3 of the third layer, and these spokes 10 are arranged in the phase of the left half of Figure 3B. If the vertical direction in the figure is considered to be 12 o'clock and 6 o'clock, the three spokes 10 are arranged in the phase of the left half to extend sequentially from the outer edge of the land 3 in the directions of 7 o'clock, 9 o'clock, and 11 o'clock.

[0028] The spokes 10 of the fourth layer extend radially in three directions from the outer edge of the land 3 of the fourth layer, and these spokes 10 are arranged in the phase shown in the right half of the figure. In the phase shown in the right half, the three spokes 10 are arranged to extend sequentially from the outer edge of the land 3 in the directions of 1 o'clock, 3 o'clock, and 5 o'clock. Therefore, as shown in Figures 1 and 2, the spokes 10 of the first and third layers, and the spokes 10 of the second and fourth layers, which sandwich the core material 7, are arranged to overlap in the thickness direction of the substrate.

[0029] <Variations in spoke count> The number of spokes 10 in each layer is not limited to three, but can be determined arbitrarily. For example, as shown in Figure 4, the spokes 10 in each layer may be arranged so that four spokes radiate outwards from the outer edge of the land 3 in each layer.

[0030] However, as shown in Figures 5A and 5B, the configuration in which the two conductive layers 6, 6 sandwiching the prepreg 5 (Figure 1) are viewed in the substrate thickness direction A1, with the spokes 10 in one conductive layer 6 (Figure 1) arranged in half the phases around the entire circumference, and the spokes 10 in the other conductive layer 6 (Figure 1) arranged in the remaining half the phases around the entire circumference, is satisfied. The same applies to the embodiments shown in Figures 6 and 7, which will be described later.

[0031] <Effects and Effects> According to the electronic circuit board 2 and electronic circuit unit 1 shown in Figures 1 and 2 described above, of the two conductive layers 6, 6 sandwiching the prepreg 5, the spokes 10 of one conductive layer 6 are arranged in half the phase around the entire circumference of the land 3. Furthermore, the spokes 10 of the other conductive layer 6 are arranged in the remaining half phase around the entire circumference of the land 3.

[0032] Therefore, heat transfer between the two conductive layers 6, 6 sandwiching the prepreg 5 can be suppressed. As a result, for example, in the process of heating and melting the solder SL applied to the land 3 in a reflow oven, heat transfer to the conductive member 11 is suppressed, and the solder SL can be sufficiently melted. Therefore, it is possible to easily solder the leads Ld of the leaded component to the land 3. The spokes 10 of the first and third layers and the spokes 10 of the second and fourth layers overlap in the thickness direction of the substrate, but because they are sandwiched by a thick core material 7, heat transfer can be suppressed, and they can be easily soldered in the same way as described above.

[0033] A multilayer substrate consists of conductive layers 6,6 provided on both sides of an insulating resin sheet 5, which serves as an insulating layer, and an insulating core material 7, which are laminated in the thickness direction of the substrate. Therefore, power supply and general signal lines can be provided in the inner layers of the multilayer substrate, making it possible to secure a large mounting space on the surface of the multilayer substrate.

[0034] The electronic circuit unit 1 comprises the electronic circuit board 2 and leaded components soldered to the lands 3. In this case, the lead Ld of the leaded components can be easily soldered to the lands 3, thereby increasing the yield and reducing manufacturing costs compared to conventional structures. Furthermore, the electronic circuit unit 1 comprises an electronic circuit board 2 and electronic components 4 supported on the electronic circuit board 2. In this case, since the electronic circuit unit can be made with improved solderability, the yield can be increased and manufacturing costs can be reduced compared to conventional structures.

[0035] <Regarding other embodiments> In the following description, parts corresponding to matters previously described in each embodiment will be denoted by the same reference numerals, and redundant explanations will be omitted. When only a part of the configuration is described, the other parts of the configuration will be the same as those in the previously described embodiment unless otherwise specified. Identical configurations will produce the same effects. Not only are combinations of the parts specifically described in each embodiment possible, but partial combinations of embodiments are also possible, provided that there are no particular problems with the combination.

[0036] [Second embodiment: Spoke modification, Figure 6] As shown in Figure 6, the spokes 10 of each layer may be curved in the circumferential direction A3 as they move radially outward A2 from the outer edge of the land 3.

[0037] [Third embodiment: Spoke modification, Figure 7] As shown in Figure 7, each spoke 10 of each layer may have a configuration comprising: a first straight portion 10a extending linearly radially outward A2 from the outer peripheral edge of the land 3; a bent portion 10b bending in one circumferential direction A3 from the outer diameter edge of the first straight portion 10a; and a second straight portion 10c extending linearly radially outward A2 from the tip of the bent portion 10b.

[0038] [Fourth embodiment: double-sided substrate, Figure 8] As shown in Figure 8, the electronic circuit board 2 may be a double-sided board in which conductive layers 6, 6 are provided on both sides of a core material 7 which is an insulating layer. If the core material 7 is made thinner than the core material in the multilayer board described above, there is a concern that heat will be more easily transferred between the conductive layers 6, 6 on both sides. Even in such a case, the connecting portion 10 in one conductive layer 6 is positioned at half the phase of the entire circumference. Furthermore, the connecting portion 10 in the other conductive layer 6 is positioned at the remaining half of the phase of the entire circumference, so that heat transfer between the two conductive layers 6, 6 sandwiching the core material 7 can be suppressed.

[0039] Motor busbars may be soldered to land 3 on the electronic circuit board 2. While embodiments for carrying out the present invention have been described above based on the embodiments, the embodiments disclosed herein are illustrative in all respects and are not restrictive. The scope of the present invention is indicated by the claims rather than the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of Symbols]

[0040] 1...Electronic circuit unit, 2...Electronic circuit board, 3...Land, 4...Electronic component, 5...Insulating resin sheet (insulating layer), 6...Conductive layer, 7...Core material, 10...Spoke (connecting part), 11...Conductive member

Claims

1. An electronic circuit board comprising a multilayer substrate composed of multiple layers in which insulating layers and conductive layers are alternately laminated, or a double-sided substrate in which conductive layers are provided on both sides of an insulating layer, wherein the conductive layers of the multilayer substrate or the double-sided substrate have circular or elliptical lands connected to through-holes and conductive members connected via connecting portions extending radially outward from the outer edge of the lands, An electronic circuit board in which, when the two conductive layers sandwiching the insulating layer are viewed in the thickness direction of the substrate, the connecting portion of one conductive layer is arranged in half the phase around the entire circumference of the land, and the connecting portion of the other conductive layer is arranged in the remaining half phase around the entire circumference of the land.

2. An electronic circuit board according to claim 1, wherein the insulating layer is an insulating resin sheet.

3. An electronic circuit board according to claim 2, wherein the conductive layer provided on both sides of the insulating resin sheet and the insulating core material are laminated in the thickness direction of the board, forming a multilayer board.

4. An electronic circuit unit comprising an electronic circuit board according to claim 1 or claim 2, and an electronic component supported on the electronic circuit board.

5. An electronic circuit unit comprising an electronic circuit board according to claim 1 or claim 2, and leaded components soldered to the lands.

Images