JP5569820B2 - A circuit board that electrically connects the terminal block to the circuit pattern on the board by reflow soldering - Google Patents

Description

  The present invention relates to a terminal block and a circuit board including the terminal block.

  A terminal block is known as an interface for electrically connecting a circuit pattern portion formed on a substrate and electrical components. The terminal block is used by being mounted on a substrate, and terminals of electrical components are fixed to the terminal block. The terminal block is usually mounted by soldering on a substrate.

  FIG. 6 is known as an example of such a terminal block. FIG. 6 is a partially exploded perspective view of a conventional terminal block and a circuit board including the terminal block. As shown in FIG. 6, a conventional terminal block and a circuit board 11 having the terminal block include a board 12, a circuit pattern 13 formed on one main surface 12 a of the board 12, and a main surface 12 a of the board 12. And a conductive terminal block 14 electrically connected to the land 13a of the circuit pattern 13.

  As shown in FIG. 6, the terminal block 14 is for attaching the electrical component terminal 5 and electrically connecting the land 13 a of the circuit pattern 13 formed on the substrate 12 to the terminal 5. The terminal 5 has a wire (not shown) fixed on one end side, a through hole 5a for inserting the fixing screw 6 on the other end side, and the terminal block 14 is also a tap for inserting the fixing screw 6. It has a portion 14c.

  Therefore, by inserting the fixing screw 6 into the through hole 5a of the terminal 5 and the screw insertion hole 14c1 of the tap portion 14c of the terminal block 14 and engaging with the inner wall surface 14c2, the terminal 5 is interposed via the terminal block 14. It is connected and fixed to the substrate 12. In FIG. 6, the terminals 5 and the fixing screws 6 do not constitute the circuit board 11.

  The terminal block 14 includes a pedestal portion 14a having a terminal mounting surface 14a1 to which the terminal 5 is mounted, and eight fixing and connecting lead legs extending to the opposite side of the pedestal portion 14a from the terminal mounting surface 14a1. 14f.

  The lead legs 14 f are inserted into the through holes 12 b of the substrate 12 formed for connection and fixation, and the lead legs 14 f are fixed in the through holes 12 b by the solder 7. Here, the lead foot 14 f and the circuit pattern 13 (land 13 a) are electrically connected via the solder 7.

  Soldering is performed by a flow method in which the solder 7 is supplied from the bottom side of the substrate 12 (the surface opposite to the main surface 12a). In the soldering by the flow method, the bottom surface side of the substrate 12 is immersed in the surface layer of the solder melted in the solder dip tank, so that the solder 7 is supplied through the through hole 12b of the substrate 12, and the lead inside the through hole 12b. The legs 14f are soldered.

Japanese Utility Model Publication No. 54-149648

  However, the conventional terminal block and the circuit board including the terminal block are soldered by the flow method as described above. That is, by immersing the bottom surface side of the substrate 12 in the surface layer of the solder melted in the solder dip tank, the solder 7 is supplied from the bottom surface side of the substrate 12 to solder the lead legs 14f inside the through hole 12b. In general, it is difficult to finish soldering, and it may be necessary to check soldering and correct soldering, which increases man-hours and may reduce yield.

  Moreover, since the melting point of lead-free solder used in recent years is higher than that of solder using lead, there is a possibility that the rise (solder rise) of the solder in the through hole of the board is further deteriorated.

  In addition, since the conventional terminal block is a discrete part with lead feet, it takes mounting man-hours such as insertion of lead feet into the through-hole of the board, soldering by flow method, confirmation of soldering, etc. Reduction is required.

  Further, when the terminal block is used for the output unit of the power supply device and supplies power to an external device, the terminal block needs to support high voltage and large current. In the case where the lead foot and the through hole of the board are fixed with solder as in the conventional terminal block, the contact area (conduction area) through the solder between the lead leg of the terminal block and the land of the board is compared. Therefore, when a large current flows, unnecessary power loss (pattern loss) and accompanying heat generation may occur.

  In addition, in the present age when electronic devices are becoming smaller, even terminal blocks are required to be further reduced in size and height. In particular, the terminal blocks are crimped onto the terminal blocks via fixing screws. Considering that a terminal such as a terminal is mounted and a cover is disposed above the terminal, a terminal block that is as low as possible and a circuit board including the terminal block are required.

  Furthermore, in the conventional terminal block 14 as shown in FIG. 6, the terminal 5 is screwed through the terminal block 14. For this reason, the load due to the rotational torque acting on the terminal block 14 when the screws are tightened is applied to the solder (not shown in FIG. 6) which is the connecting portion between the substrate 12 and the lead foot 14f, and stress remains in the solder. .

  In this case, when used in an environment where the temperature changes drastically, cracks may occur in the solder during repeated thermal shocks. In particular, in FIG. 6, since the circuit pattern 13 (land 13a) and the lead foot 14f in the circuit board 11 are in contact with each other via solder, cracks are generated in the solder, so that electrical connection is finally achieved. There was a problem that it was damaged and stopped functioning.

  Accordingly, the present invention has been made in view of the above circumstances, and realizes a surface-mounting terminal block for fixing a plate-like terminal block to a land of the substrate by surface contact, and a circuit board including the surface mounting terminal block. It is. In other words, reflow soldering is possible to improve the yield, and since it does not have lead feet, the mounting man-hours are reduced, and pattern loss corresponding to large currents can be achieved by surface contact with the land of the board. In addition to realizing a low-profile terminal block and providing a positioning projection on the terminal block, this terminal reduces stress on the solder and prevents solder cracks from occurring An object of the present invention is to provide a table and a circuit board including the table.

To achieve the above object, the present invention is a circuit board for electrically connecting a terminal block to a circuit pattern on a board by soldering by a reflow method, and the circuit board has the circuit pattern on a main surface. A board and a conductive plate-like terminal block joined and electrically connected to the land of the circuit pattern, the terminal block having a plane portion having a terminal mounting surface to which the terminal is mounted; A plurality of convex portions are provided , and a bottom surface portion is provided on the opposite side of the flat surface portion, and the land is formed corresponding to the shape of the terminal block so as to secure a contact area with the terminal block. , in a recess provided in the substrate, by fitting a plurality of protrusions, characterized in that said circuit pattern and the bottom part is conductive bonded by surface contact with the solder.

Further, the present invention is characterized by including a tap portion that protrudes from the bottom surface portion and has a screw insertion hole into which a fixing screw for fixing the terminal can be inserted from the flat surface portion .

Furthermore, the tap unit of the present invention is characterized in that it is inserted before Symbol the opening provided in the substrate larger than the outer diameter of the tap unit.

  Moreover, the said convex part of this invention is distribute | arranged so that it may oppose on both sides of the center part of a bottom face part in the edge part vicinity of the said bottom face part.

Further, the terminal block of the present invention is capable of confirming the state of solder interposed between the circuit pattern and the terminal block by a hole and / or a notch penetrating from the flat surface portion to the bottom surface portion. Features.

  According to the terminal block of the present invention and the circuit board including the terminal block, it is not necessary to adopt a flow method in which solder is supplied from the bottom surface side of the substrate, and soldering by a reflow method is possible. That is, when the terminal block is mounted on the board, the terminal block can be automatically mounted by the mounter. The terminal block is placed on the board on which the solder paste has been applied in advance, and the solder joint is collectively performed in a horizontal transfer type continuous furnace. It can be carried out.

  Therefore, the mounting process can be greatly reduced as compared with a terminal block as a discrete component having a conventional lead foot. In addition, since it is possible to reduce the decrease in yield due to the conventional solder deficiency and the need for soldering confirmation and soldering correction, man-hours can be reduced and throughput can be improved.

  Further, since the soldering is performed by the reflow method, the solder finish is improved and the yield is improved as compared with the flow method which is the soldering of discrete components.

  Further, even when the terminal block is used for the output unit of the power supply device and supplies power to the external device, the terminal block according to the present invention is a surface mount terminal block, and is a land between the terminal block and the board. Is in surface contact via solder, and the contact area (conduction area) is large and the current capacity is large, so even if a large current flows, unnecessary power loss (pattern loss) and It is possible to provide a terminal block that can be used for an output part of a power supply device and can be used for an output part of a power supply device, and a circuit board including the terminal block.

  Further, the terminal block according to the present invention is a surface-mounting terminal block, which is formed in a plate shape and is mounted so as to be attached to a substrate. Therefore, a low-profile terminal block and a circuit board including the terminal block are provided. Even if a terminal such as a crimp terminal is mounted on the terminal block via a fixing screw, and a cover is mounted on the terminal block, the terminal block is mounted on the terminal block compared to the case where a terminal is mounted on the conventional terminal block. Can be realized.

  In addition, since the terminal block according to the present invention has a confirmation hole for confirming the soldering state between the land on the board and the terminal block, the soldering between the land and the terminal block via the solder is good. It can be easily confirmed that a fillet is generated and the solder is melted by the generation of the fillet.

  Further, since the positioning projection is provided on the bottom surface of the terminal block, the terminal block is positioned by fitting with the recess of the substrate. Therefore, when the terminal is screwed through the terminal block, the rotational torque acting on the terminal block by screw tightening can reduce the load stress remaining on the solder and prevent the occurrence of solder cracks. Will not be damaged.

  In this case, the convex portion is positioned on the end portion side of the bottom surface portion of the terminal block, so that it is located in a region sandwiched between the convex portions facing each other through the central portion of the terminal block due to rotational torque due to screw tightening. It is possible to further prevent load stress from remaining on the solder.

1 is a partial perspective view showing an embodiment of a circuit board according to the present invention. It is a disassembled perspective view which shows the circuit board of FIG. It is a downward perspective view which shows the terminal block of FIG. It is sectional drawing along the IV-IV line of FIG. It is sectional drawing along the VV line of FIG. It is a partial exploded perspective view of the conventional terminal block and a circuit board provided with the same.

  Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 to 5. FIG. 1 is a partial perspective view showing an embodiment of a circuit board according to the present invention. FIG. 2 is an exploded perspective view showing the circuit board of FIG. FIG. 3 is a lower perspective view showing the terminal block of FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. FIG. 5 is a cross-sectional view taken along line VV in FIG. In the embodiment of the present invention, the same parts as those in the background art described above are denoted by the same reference numerals and the description thereof is omitted.

  In addition, the terminal block according to the present invention and the circuit board provided with the terminal block are surface-mounted because the terminal block electrically connected to the circuit pattern provided on the substrate is formed in a plate shape by a conductive material. It functions as a terminal, and various effects can be achieved by conducting electrical connection between the terminal block and the circuit pattern (land) of the board through solder in surface contact.

[Configuration outline of terminal block and circuit board including the terminal block according to the embodiment]
As shown in FIGS. 1 and 2, the circuit board 1 according to the present embodiment is mounted on the substrate 2, the circuit pattern 3 formed on one main surface 2 a of the substrate 1, and the main surface 2 a of the substrate 2. And a conductive and plate-like terminal block 4 mounted (joined) on the land 3a of the circuit pattern portion 3 and electrically connected thereto.

  As shown in FIG. 2, the terminal block 4 is for attaching a terminal 5 of an electrical component and electrically connecting the land 3 a of the circuit pattern portion 3 formed on the substrate 2 to the terminal 5. The terminal 5 has a wire (not shown) fixed on one end side, and has a through hole 5a for inserting a fixing screw 6 on the other end side, and the terminal block 4 is also a screw for inserting the fixing screw 6 It has an insertion hole 4c1.

  Accordingly, by screwing the fixing screw 6 into the through hole 5a of the terminal 5 and the screw insertion hole 4c1 of the terminal block 4, the terminal 5 is connected and fixed to the substrate 2 via the terminal block 4. Yes. In FIG. 2, the terminals 5 and the fixing screws 6 do not constitute the circuit board 1. Instead of the crimp terminal such as the terminal 5, it is also possible to fix the bus bar used for a power line or the like and corresponding to a large current to the terminal block 4 instead of the terminal 5.

[Terminal block configuration]
As shown in FIGS. 1 to 3, the terminal block 4 is made of a conductive material such as copper, and the overall shape is formed in a substantially rectangular plate shape. The terminal block 4 is mounted (bonded) on the land 3a of the substrate 2. The bonding surface of the terminal block 4 to the substrate is the bottom surface portion 4b, and the surface opposite to the bonding surface of the terminal block 4 is the flat surface portion. 4a. In the present embodiment, a total of four holes are formed so as to surround the center portion C (see FIG. 1) of the terminal block 4, and each hole penetrates from the flat surface portion 4a side to the bottom surface portion 4b side. Yes.

  A pair of holes facing each other with the center portion C interposed therebetween is a screw insertion hole 4c1 formed by a tapped inner wall surface 4c2, and a male screw portion of a fixing screw 6 for fixing the terminal 5 is screwed together. Is. As shown in FIGS. 3 and 4, the screw insertion hole 4c1 is provided with a tap portion 4c projecting in a cylindrical shape on the side of the bottom surface portion 4b so that the female screw can be cut off. It is possible to increase the area of the inner wall surface 4c2.

  The other pair of holes facing each other with the central portion C interposed therebetween is a confirmation hole 4d for confirming the soldering state between the land 3a on the substrate 2 and the terminal block 4. When the connection between the land 3a and the terminal block 4 via the solder 7 is good, a solder fillet 7a is generated as shown in FIG. That is, it is confirmed that the solder fillet 7a is generated by the surface tension of the molten solder on the contact surface through the solder 7 with the land 3a at the bottom of the confirmation hole 4d, and the solder 7 is melted by the generation of the solder fillet 7a. It is easily confirmed that good soldering has been performed.

  Although the confirmation hole 4d is a hole whose periphery is closed, the solder fillet 7a is generated even in a notch shape extending from the side surface portion of the terminal block 4, and therefore can be a notch shape.

  As shown in FIG. 3, the bottom surface portion 4 b of the terminal block 4 is opposed to the center portion C of the terminal block 4, and is a positioning convex portion in the vicinity of the corner of the terminal block 4 of the rectangular plate-like body. 4e is arranged. In the present embodiment, the convex portion 4 e is formed in a columnar shape, and is fitted into the concave portion 2 b provided on the main surface of the substrate 2.

  The convex portion 4e is positioned by positioning the terminal block 4 with respect to the substrate 2 and by screwing acting on the terminal block 4 when the terminal 5 is screwed through the terminal block 4 by fitting with the concave portion 2b. The load stress applied to the solder 7 by the rotational torque is reduced, and the occurrence of solder cracks is prevented. Further, in order to reduce the positioning of the terminal block 4 and the load stress applied to the solder 7, it is necessary that there are a plurality of convex portions 4 e instead of a single one.

  Moreover, the convex part 4e is arrange | positioned at the edge part side of the bottom face part 4b of the terminal block 4, By the rotational torque by screw fastening, the area | region R (FIG. 5) pinched | interposed into the convex part 4e which opposes via the center part C 3 can be further prevented from remaining a load stress on the solder 7 located within the one-dot chain line 3).

[Substrate structure]
As shown in FIGS. 1 and 2, the substrate 2 is made of a glass epoxy resin material or the like as an insulating member, and has a circuit pattern 3 made of a conductor such as copper foil on the surface of the substrate 2. It is joined to the terminal block 4 and the solder 7 on 3a.

  As shown in FIGS. 2, 4, and 5, the land 3 a is formed in a large size corresponding to the shape of the terminal block 4, and ensures a contact area (conduction area) with the terminal block 4. For this reason, even when the current capacity is large and a large current flows, unnecessary power loss (pattern loss) and the associated heat generation do not occur, and the output unit of the power supply device that supports high voltage and large current It can be used.

  Further, the substrate 2 is processed corresponding to the shape of the terminal block 4. That is, as shown in FIGS. 2 and 5, the concave portion 2 b is formed corresponding to the convex portion 4 e disposed on the bottom surface portion 4 b side of the terminal block 4. The convex portion 4e is for fitting with the concave portion 2b and positioning and fixing the terminal block 4. Therefore, the shape of the concave portion 2b is formed so as to be fitted with the convex portion 4e (see FIG. 5). ). In addition, the recessed part 2b does not need to penetrate a board | substrate, if it can fit with the convex part 4e.

  Further, as shown in FIGS. 2 and 4, when the cylindrical tap portion 4c protrudes on the bottom surface portion 4b side of the terminal block 4 as in this embodiment, the opening is also formed on the substrate 2 side correspondingly. Part 2c is formed. The tap portion 4c performs tapping when forming the inner wall surface 4c2 with the female screw cut, but when the tap is raised, a burr is generated at the tip portion 4c3 (see FIGS. 3 and 4) of the tap portion 4c. Is also envisaged.

  For this reason, by providing a positioning convex portion 4e separately from the tap portion 4c, positioning is performed at the convex portion 4e, and the tap portion 4c is a barrier when the tap is set up with the substrate 2 and the gap 8 intentionally provided. And the like can be prevented from interfering with the substrate 2. Therefore, in this embodiment, the inner diameter of the opening 2c of the substrate 2 is formed larger than the outer diameter of the tap portion 4c.

  Moreover, when providing the convex part 4e for positioning other than the tap part 4c, when the mounting | wearing of the terminal 5 is considered, the tap part 4c needs to be formed in the position from the inside of the terminal block 4. FIG. By providing the convex portion 4e for positioning separately from the tap portion 4c, that is, by arranging the convex portion 4e on the end portion side of the bottom surface portion 4b of the terminal block 4, the rotational torque due to screw tightening causes the center It becomes possible to prevent residual load stress on the solder 7 located in the region R (inside the one-dot chain line in FIG. 3) sandwiched between the convex portions 4e facing each other via the portion C.

  On the other hand, when the processing accuracy of the tap portion 4c is high, the tap portion 4c itself can be used as the positioning convex portion 4e without separately providing the positioning convex portion 4e in addition to the tap portion 4c.

  In the present embodiment, the recess 2b and the opening 2c are provided continuously for ease of router processing. Naturally, the recesses 2b are not continuous, and the recesses 2b are closed around each other. A configuration in which the opening 2c is not continuous may be employed.

[Fixing the terminal block to the board]
In order to describe a method of fixing the terminal block 4 to the substrate 2, first, a solder paste is applied in advance on the lands 3a of the substrate 2 by a dispenser.

  Next, the terminal block 4 is placed on the substrate 2. As is clear from FIG. 1, the terminal block 4 is provided with a screw insertion hole 4 c 1 and a confirmation hole 4 d so as to surround the center portion C of the terminal block 4, and special components are also arranged in the center portion C. It has not been. Accordingly, the terminal block 4 can be automatically mounted on the land 3a of the substrate 2 by the mounter by vacuum-sucking the central portion C with the mounter head of the mounter.

  Thereafter, the solder paste existing between the land 3a of the substrate 2 and the bottom surface portion 4b of the terminal block 4 is melted by a horizontal transfer type continuous furnace, and solder joining is performed collectively. Solder joining of the terminal block 4 to the substrate 2 is completed.

DESCRIPTION OF SYMBOLS 1 Circuit board 2 Board | substrate 2a Main surface 2b Recessed part 2b1 Inner wall surface 2c Opening part 2c1 Inner wall surface 3 Circuit pattern 3a Land 4 Terminal block 4a Flat surface part 4b Bottom surface part 4c Tap part 4c1 Screw insertion hole 4c2 Inner wall surface 4c3 Tip part 4d Confirmation hole 4e Projection 5 Terminal 5a Through hole 6 Fixing screw 7 Solder 7a Solder fillet 8 Gap 11 Circuit board 12 Substrate 12a Main surface 12b Through hole 13 Circuit pattern 13a Land 14 Terminal block 14a Base portion 14a1 Terminal mounting surface 14c Tap portion 14c1 Screw insertion hole 14c2 inner wall surface 14f lead foot

Claims (5)

A circuit board that electrically connects the terminal block to a circuit pattern on the board by soldering using a reflow method,
The circuit board is
A substrate having the circuit pattern on a main surface;
A plate-like terminal block having electrical conductivity that is joined and electrically connected to the land of the circuit pattern;
The terminal block is
A plane portion having a terminal mounting surface to which the terminal is mounted;
A plurality of convex portions are provided, and a bottom surface portion located on the opposite side of the flat surface portion is provided,
The land is formed corresponding to the shape of the terminal block so as to ensure a contact area with the terminal block,
A circuit board, wherein the plurality of projections are fitted into recesses provided in the board, whereby the bottom surface part and the circuit pattern are joined and brought into contact by surface contact via solder. The circuit board according to claim 1, further comprising a tap portion that protrudes from the bottom surface portion and has a screw insertion hole into which a fixing screw for fixing the terminal can be inserted from the flat surface portion .   The circuit board according to claim 2, wherein the tap portion is inserted into an opening provided in the substrate that is larger than an outer diameter of the tap portion.   4. The mounting portion according to claim 1, wherein the convex portion is disposed so as to face the center portion of the bottom surface portion in the vicinity of the end portion of the bottom surface portion. 5. Circuit board.   The terminal block is capable of confirming a state of solder interposed between the circuit pattern and the terminal block by a hole and / or a notch penetrating from the flat surface portion to the bottom surface portion. The circuit board according to any one of claims 1 to 4.

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