Assembly comprising a printed circuit board and a connector and method for arranging a connector on a printed circuit board

Abstract

Assembly (1) comprising a printed circuit board (2) and at least one connector (3) reflow soldered in an edge region (4) of the printed circuit board (2), wherein the connector (3) is further mechanically fastened to the printed circuit board (2) by means of at least one connecting element (5).

Description

[0001] The present invention relates to an assembly comprising a printed circuit board and at least one connector reflow-soldered in an edge region of the printed circuit board. It further relates to a method for arranging a connector on a printed circuit board. The connector is, in particular, designed as a surface-mount connector with one or more connecting elements configured as sockets or plugs, which enable an electrical connection of the assembly with external elements.

[0002] If such a connector is to be fixed to an edge area of ​​a printed circuit board (PCB), it is held in position by a PCB support until the reflow soldering process, which creates the electrical and mechanical connection between the PCB and the connector, is complete. The PCB support is formed by an edge area of ​​the PCB, which may already be separated from the PCB itself by a groove and is often removed after reflow soldering if space is limited. Until the reflow soldering is complete, the connector rests at least partially on the PCB support.

[0003] It is an object of the present invention to simplify and reduce the cost of the manufacturing process for an assembly comprising a printed circuit board and at least one connector reflow-soldered in an edge region of the printed circuit board.

[0004] This task is solved by the subject matter of the independent claims. Advantageous embodiments and further developments are the subject matter of the dependent claims.

[0005] According to one aspect of the invention, an assembly is specified comprising a printed circuit board and at least one connector reflow-soldered in an edge region of the printed circuit board, wherein the connector is further attached to the printed circuit board via a mechanical connecting element.

[0006] In this context, "fastening" refers to a three-dimensional fixing that defines the position of the connector on the printed circuit board. Specifically, this includes fixing in the z-direction perpendicular to the plane of the printed circuit board.

[0007] It is therefore planned to create an additional connection between the printed circuit board (PCB) and the connector via a mechanical connecting element. This connection serves to fix the connector to the PCB until the reflow soldering process, without the need for PCB support. After reflow, the solder joint takes over the mechanical and electrical connection between the PCB and the connector; however, the mechanical connecting element can remain in the assembly and, unlike PCB support, does not need to be removed.

[0008] This assembly offers the advantage that a stable mechanical connection between the connector and the circuit board is established as soon as the connector is placed on the board, ensuring the connector is securely fixed even before the reflow process. During reflow soldering, which also requires transporting the circuit board, the connector remains firmly in place. This eliminates the need for subsequent removal of the connector. By eliminating the need for PCB support, the yield per PCB panel can be increased. Furthermore, fixing the connector in place improves the assembly's mechanical robustness and reduces stress on the solder joint.

[0009] The connector can be connected to the circuit board, in particular by a positive locking or friction locking mechanism.

[0010] According to one embodiment, the connector is arranged at the edge of the printed circuit board (PCB) such that it projects beyond the PCB. In this embodiment, the connector is not entirely flush with the PCB. In particular, it can project so far beyond the PCB at the edge that its center of gravity is no longer located on the PCB. In such an arrangement, a mechanical fastener that secures the connector to the PCB is particularly advantageous.

[0011] There are various ways to secure the connector to the circuit board. For example, the connector can be attached to the circuit board using snap-in hooks. It can also be attached to the circuit board using at least one heat-stitched connection element.

[0012] According to another embodiment, the connector is connected to the circuit board via a crimp dome or a dome with scraper ribs. In this embodiment, a friction-fit connection between the connector and the circuit board is established when the crimp dome or the dome with scraper ribs is inserted into the designated receptacle. The crimp dome or the dome with scraper ribs can be located either on the connector or on the circuit board.

[0013] According to another embodiment, the connector is connected to the circuit board via an expansion element. The expansion element is, in particular, a separate component that is inserted into corresponding through-holes in the connector and in the circuit board and anchored there by expansion, thereby connecting the connector and the circuit board.

[0014] In all embodiments, it is possible to arrange the connecting element in a stepped hole in the printed circuit board. This has the advantage that the connecting element does not protrude from the underside of the printed circuit board. Rather, for example, a snap-lock head or a rivet head is countersunk in a stepped hole in the printed circuit board.

[0015] The described assembly has the advantage that the connector is securely fixed to the circuit board for the reflow soldering process without the need for PCB support. The various connector options allow for secure fixation of the connector to the circuit board, which can be maintained even after the reflow process.

[0016] The at least one mechanical connecting element can be located in various areas at the interface between the connector and the printed circuit board (PCB). Typically, the connector features alignment pins for aligning the connector on the PCB in the XY direction. These alignment pins can be used for fixation, for example, by being fitted with a crimp dome, thus acting as a mechanical connecting element that secures the connector to the PCB in all three dimensions.

[0017] According to a further aspect of the invention, a method for arranging a connector on a printed circuit board is specified, wherein the connector is attached to the printed circuit board by means of a mechanical fastening element and is subsequently connected to the printed circuit board via a solder joint in a reflow soldering process.

[0018] In surface-mount technology (SMT) soldering, solder deposits are first applied to designated areas. During reflow soldering, these deposits are melted and, upon solidification, form the desired mechanical and electrical connection. A reflow soldering process can be performed, for example, in a continuous oven through which the assemblies are transported. During reflow soldering, all solder deposits on the assembly are melted at the appropriate melting temperature and then solidify again. In this way, a large number of solder joints can be created simultaneously.

[0019] The method has the advantage that the mechanical connecting element securely attaches the connector to the circuit board during transport before and during the soldering process, until the solder joint is load-bearing.

[0020] Embodiments of the invention are described below by way of example with reference to schematic drawings. Fig. Figure 1 shows a sectional view of an assembly according to a first embodiment of the invention; Fig. 2 shows a sectional view of an assembly according to a second embodiment of the invention; Fig. Figure 3 shows a sectional view of an assembly according to a third embodiment of the invention; Fig. 4 shows a sectional view of an assembly according to a fourth embodiment of the invention and Fig. Figure 5 shows a sectional view of an assembly according to a fifth embodiment of the invention.

[0021] Fig. Figure 1 shows a sectional view of an assembly 1 with a printed circuit board 2 and a connector 3, which is located in an edge region 4 of the printed circuit board 2 on a top surface 10 of the printed circuit board 2. The printed circuit board 2 is a PCB substrate.

[0022] The connector 3 is connected to the circuit board 2 via a solder joint (not shown) or multiple solder joints (not shown) produced in a reflow process. In addition, a mechanical connecting element 5 is also provided, which connects the circuit board 2 to the connector 3 even before the reflow soldering.

[0023] In the Fig. In the embodiment shown in Figure 1, the connecting element 5 is designed as a locking hook 7 and is integrally formed with the connector 3. The printed circuit board 2 has a stepped bore 6 corresponding to the locking hook 7, into which the connecting element 5 is inserted to connect the connector 3 to the printed circuit board 2. The locking hooks 7 are initially pressed together and snap into place after passing through the first step of the stepped bore 6. They then rest in the second step of the stepped bore 6 in the area of ​​the underside 11 of the printed circuit board 2 and are supported by projections 8 to prevent the connector 3 from being removed from the printed circuit board 2.

[0024] The connector 3 is thus fixed to the circuit board 2. The connector 3 protrudes a distance a beyond the edge region 4 of the circuit board 2. In the illustrated embodiment, the center of gravity of the connector 3 is also located only slightly above the circuit board 2, so that without the mechanical fixation by the connecting element 5, the connector 3 might not remain stable in the position shown on the circuit board 2, for example during transport before and during the soldering process.

[0025] By means of the connection using the connecting element 5, the assembly 1 can be subjected to a reflow soldering process without the need for the connector 3 to be supported, for example, by a PCB support to prevent it from tipping off the circuit board 2.

[0026] Fig. Figure 2 shows a second embodiment of assembly 1. This differs from the one in Fig. 1 shown by the design of the connecting element 5. In the in Fig. In the embodiment shown in Figure 2, the connecting element 5 is designed as a hot-stitched pin. By means of a rivet head 9 formed during hot-stitching, the connecting element 5 is anchored in the stepped bore 6, so that the rivet head 9 rests against the projection 8 and the connector 3 can no longer be removed from the circuit board 2.

[0027] Fig. Figure 3 shows another embodiment of assembly 1. This differs from those shown in the Fig. 1 and Fig. Figure 2 shows the design of the connecting element 5, which in the illustrated embodiment is configured as a crimp dome 12, also shown in a bottom view in the figure. In the illustrated embodiment, the crimp dome 12 is arranged in a central area of ​​the connector 3. However, several domes can also be provided, which are then, for example, arranged in lateral areas of the connector 3.

[0028] The connector 3 may also have alignment pins (not shown in the figure) which serve to align the connector 3 on the circuit board 2. The alignment pins could also be designed as crimp domes, and thus as connecting elements, in addition to or as an alternative to the crimp dome 12.

[0029] Fig. Figure 4 shows a further embodiment of assembly 1, which differs from the one described in the Fig. The elements shown in 1 to 3 differ in the design of the connecting element 5. In the case of the Fig. In the embodiment shown in Figure 4, the connecting element 5 is designed as a dome 14 with scraper ribs 15 shown as examples, which form a close friction-fit connection with a corresponding bore in the circuit board 2.

[0030] Fig. Figure 5 shows a further embodiment of assembly 1, which differs from the one described in the Fig. The elements shown in 1 to 4 differ in the design of the connecting element 5. In the case of the Fig. In the embodiment shown in Figure 5, the connecting element 5 is designed as a separate spreading element 17. In the left half, the spreading element 17 is shown in its unassembled form, while in the right half it is shown in its fully assembled form.

[0031] After the connector 3 is placed on the top surface 10 of the circuit board 2, the expanding element 17 is inserted into a bore in the connector 3 that aligns with a bore 20 in the circuit board 2. Once the expanding element 17 is fully inserted into the bore 20, it is expanded by depressing the piston 19. The head 18 of the expanding element 17 then rests against the underside 11 of the circuit board and, due to its expanded state, can no longer be retracted through the bore 20. The connecting element 5 is thus anchored in the bore 20, and the circuit board 2 and the connector 3 are firmly connected.

Claims

[1] Assembly (1) comprising a printed circuit board (2) and at least one connector (3) reflow-soldered in an edge region (4) of the printed circuit board (2), wherein the connector (3) is further mechanically fastened to the printed circuit board (2) via at least one connecting element (5). [2] Assembly (1) according to claim 1, wherein the connector (3) is positively connected to the printed circuit board (2). [3] Assembly (1) according to claim 1, wherein the connector (3) is frictionally connected to the circuit board (2). [4] Assembly (1) according to one of claims 1 to 3, wherein the connector (3) is arranged in the edge region (4) of the printed circuit board (2) in such a way that it projects beyond the printed circuit board (2). [5] Assembly (1) according to one of claims 1 to 4, wherein the connector (3) is connected to the circuit board (2) via latching hooks (7). [6] Assembly (1) according to one of claims 1 to 4, wherein the connector (3) is connected to the circuit board (2) via at least one hot-stamped fixing element. [7] Assembly (1) according to one of claims 1 to 4, wherein the connector (3) is connected to the printed circuit board (2) via a crimp dome (12) or a dome (14) with scraper ribs (15). [8] Assembly (1) according to one of claims 1 to 4, wherein the connector (3) is connected to the printed circuit board (2) via a spreading element (17). [9] Assembly (1) according to one of claims 1 to 8, wherein the connecting element (5) is arranged in a stepped bore (6) in the printed circuit board (2). [10] Method for arranging a connector (3) on a printed circuit board (2), wherein the connector (3) is mechanically fastened to the printed circuit board (2) by means of a connecting element (5) and is then connected to the printed circuit board (2) via a solder connection in a reflow soldering process.

Images