PCB strain relief component

Abstract

The present invention relates to an electronic device. The electronic device includes: a printed circuit board having at least one edge; and a strain relief member including a plurality of overlapping and spaced slots that cooperate with the at least one edge to define resilient tabs for redistributing strain induced in the printed circuit board.

Description

Technical Field

[0001] The present invention generally relates to electronic products, and more particularly, to a strain relief for an electronic device. Background Art

[0002] Printed circuit boards (PCBs) are widely used in vehicle applications for mounting sensors that assist in vehicle operation, such as image sensors, rain sensors, proximity sensors, light sensors, etc. The sensors can be fixed to the PCB with conductive solder. The PCB can be connected to another PCB, a main board, or other components or substrates through fasteners, adhesives, and / or compression between housing components. The interface between the connecting member and the PCB may be subjected to a high level of strain. Summary of the Invention

[0003] In one aspect, an electronic device includes: a printed circuit board having at least one edge; and a strain relief including a plurality of overlapping and spaced-apart slots that cooperate with the at least one edge to define a resilient tab for redistributing strain induced in the printed circuit board.

[0004] In another aspect, an electronic device includes a printed circuit board having a first edge and a second edge extending transversely to each other. The strain relief includes a plurality of overlapping and spaced-apart slots that cooperate with the first edge and the second edge to define a resilient tab. The plurality of slots includes a first slot extending away from the first edge. A second slot extends away from the second edge. A third slot overlaps the first slot and the second slot to form a resilient tab. A sensor is disposed on the printed circuit board such that the strain relief redistributes strain away from the sensor.

[0005] Other objects and advantages and a more complete understanding of the present invention will be obtained from the following detailed description and the accompanying drawings. Brief Description of the Drawings

[0006] Figure 1 is a schematic diagram of an exemplary electronic device having a strain relief according to the present invention.

[0007] Figure 2 is Figure 1 an enlarged view of the strain relief.

[0008] Figure 3A is an exploded view of an electronic device connected to a main board.

[0009] Figure 3B is an enlarged top view of a partial electronic device connected to a main board.

[0010] Figure 4 is a schematic diagram of another exemplary electronic device.

[0011] Figure 5 is a schematic view of a tire pressure monitoring (TPM) sensor including another exemplary electronic device.

[0012] Figure 6A is the TPM sensor with the cover removed Figure 5 top view of.

[0013] Figure 6B is a cross-sectional view of the TPM sensor taken along line 6B-6B Figure 5 of. DETAILED DESCRIPTION

[0014] The present invention generally relates to electronic products, and more particularly, to a strain relief for an electronic device. Figures 1 to 2 An exemplary electronic device 20 is shown. Referring Figure 1 , the electronic device 20 includes a printed circuit board (PCB) 22 that extends along a centerline 24 and includes a first side 26 and a second side 28. The PCB 22 can be polygonal (square, rectangular, etc.) or circular (not shown). As shown, the PCB 22 is rectangular and includes a pair of first edges 30 that extend perpendicular to the centerline 24. A pair of second edges 32 extend parallel to the centerline 24 and interconnect with the first edges 30. The first edges 30 and the second edges 32 together define the perimeter of the PCB 22.

[0015] A sensor 40 is fixed to the first side 26 of the PCB 22. The sensor 40 can be, for example, an image sensor, a rain sensor, a proximity sensor, a light sensor, or a pressure sensor. Alternatively, the sensor 40 can be omitted (not shown). The sensor 40 can be fixed to the PCB 22 by solder formed, for example, as a ball grid array (BGA) or a pin grid array (not shown), and the solder is heated to undergo reflow to fix the sensor to the PCB 22. The solder is formed of a conductive material.

[0016] One or more openings 50 extend through the PCB 22 from the first side 26 to the second side 28. As shown, four openings 50 extend through the PCB 22 at each corner of the PCB 22. The openings 50 are symmetrically arranged about the centerline 24 (although other configurations can be considered). Each opening 50 is circular and centered on an axis 52 (refer to Figure 2 ).

[0017] The strain relief member 60 is associated with each opening 50 and is configured to help reduce or mitigate strain on the PCB 22 during / while being connected to another component. The strain relief member 60 includes a plurality of spaced-apart slots extending through the PCB 22. As Figure 2 shown, each strain relief member 60 includes a first slot 62 that extends from the first edge 30 toward the interior of the PCB. The first slot 62 may extend parallel to the second edge 32 (as shown) or transverse to the second edge (not shown). The first slot 62 extends from a peripheral end point 63 to an inner end point 64. The end point 63 may be located at the first edge 30 (as shown) or spaced from the first edge 30 (not shown). The end point 64 may be substantially aligned with the axis 52 of the opening 50 (vertically aligned as Figure 2 shown).

[0018] A second slot 72 extends from the second edge 32 toward the interior of the PCB. The second slot 72 may extend parallel to the first edge 30 (as shown) or transverse to the second edge (not shown). The second slot 72 extends from a peripheral end point 73 to an inner end point 74. The end point 73 may be located at the second edge 32 (as shown) or spaced from the second edge 32 (not shown). The end point 74 may be substantially aligned with the axis 52 of the opening 50 (horizontally aligned as Figure 2 shown). Thus, the end point 64 and the end point 74 may be positioned substantially 90° from each other about the axis 52. The end point 64 and the end point 74 may be along a straight line (as shown) or along a curve (not shown).

[0019] Although the first slot 62 and the second slot 72 are shown as straight, it should be understood that one or both of the first and second slots may be curved. The first slot 62 and the second slot 72 may extend the same length or different lengths along the PCB 22 (not shown). The first slot 62 and the second slot 72 may have the same width or different widths along the PCB 22 (not shown). The widths of the slots 62, 72 may be constant or variable.

[0020] The third slot 82 is located inside the first slot 62 and the second slot 72 and extends from the adjacent first slot 62 to the adjacent second slot 72. The third slot 82 is curved and extends circumferentially around the axis 52 of the opening 50. The third slot 82 extends to an end point 84 adjacent to the end point 64 of the first slot 62 and an end point 86 adjacent to the end point 74 of the second slot 72. The end point 84 is closer to the first edge 30 than the end point 64, such that the third slot 82 overlaps the first slot 62 by a distance O1. The end point 86 is closer to the second edge 32 than the end point 74, such that the third slot 82 overlaps the second slot 72 by a distance O2. The distance O1 and the distance O2 may be the same as or different from each other. Each of the first slot 62, the second slot 72, and the third slot 82 may extend completely through the PCB 22 (as shown) or partially through the PCB 22 (not shown).

[0021] The edges 30, 32 cooperate with the strain relief 60 to define a flexible or elastic tab 90 on the PCB 22. When the PCB 22 is rectangular, the tab 90 may be located in one or more of its corners. The tab 90 may also be adjacent to an internal opening (not shown) in the PCB 22 and formed using one or more edges defining the opening. In any case, in the example shown, each tab 90 includes the opening 50.

[0022] The tab 90 is held connected to the remainder of the PCB 22 by the hinge 92 and paired peripheral portions 94, 96 on opposite sides of the hinge portion. The hinge 92 is located between the opening 50 and the third slot 82. The peripheral portion 94 is located between the first slot 62 and the third slot 82. The peripheral portion 96 is located between the second slot 72 and the third slot 82. Thus, the overlap distances O1, O2 contribute to defining the lengths of the peripheral portions 94, 96. The hinge 92 and the peripheral portions 94, 96 cooperate to allow the tab 90 to pivot relative to the remainder of the PCB 22 in a direction generally along the axis 52 of the opening 50 or parallel to the axis 52 of the opening 50.

[0023] Reference Figures 3A to 3B In, the electronic device 20 is fixed to an electronic component, such as a main board or a main PCB 130. In one example, fasteners 140 are used to connect the electronic device 20 to the main board 130. Each fastener 140 includes a head 142 and a threaded shaft 144 extending from the head. The fastener 140 extends through the opening 50 in the PCB 22 and a corresponding opening 132 in the main board 130. As a result, the head 142 of the fastener 140 engages the PCB 22. The shaft 144 extends through the opening 50 and the opening 132. A nut 150 is connected to the shaft 144 to clamp the PCB 22 to the main board 130.

[0024] When the PCB 22 and the main board 130 are connected together ( Figure 3B),The strain can be generated in one or more ways. First, strain can be generated in the PCB 22 along the interface between the head 142 of each fastener 140 and the tab 90 on the PCB (i.e., around the opening 50). When the surface 134 is uneven or not parallel to the second side 28 of the PCB, or when electronic components (such as soldering traces) extend along the surface 134, strain can also be induced in the PCB 22.

[0025] In any case, when the tab 90 is connected to the main board 130 and strain is induced in the main board 130, the tab 90 is stressed. The strain radiates outward in each direction from the opening 50 towards the edges 30, 32 and the image sensor 40 in a manner S1. However, the strain eliminator 60 advantageously redirects a portion of the strain propagating towards the image sensor 40 so that it is instead redirected towards the edges 30, 32 of the PCB 22 in a manner S2. More specifically, the strain reaching the portion 92 is redirected outward and towards the edges 30, 32 along the peripheral portions 94, 96 between the overlapping slots 62, 72, 82. Thus, the strain that would otherwise propagate to or be adjacent to the image sensor 40 is instead redirected away from the image sensor. This unchanged strain direction / distribution may be excessive around the image sensor 40, which may cause damage to the PCB 22 and / or the solder BGA that connects the image sensor to the PCB. Therefore, the strain eliminator 60 also helps prevent cracking of the PCB 22 around the image sensor 40.

[0026] The elastic properties of the tab 90 also allow the strain to be released / redistributed because the tab can pivot or bend relative to the remainder of the PCB 22 around the hinge 92. The bending helps prevent the strain from becoming excessive and causing damage to the PCB 22 or the PCB / sensor 40 connection.

[0027] Although the fastener 140 shown is a screw that mates with a nut 150, it should be understood that other structures (e.g., rivets, plastic coupling nuts to be heat-melted, etc.) can extend through the opening 50 to connect the electronic device 20 to the main board 130. In any case, the strain eliminator 60 redistributes the strain induced by the PCB 22 / main board 130 connection away from the image sensor 40.

[0028] Figure 4 Another exemplary electronic device 220 according to the present invention is shown. Figure 4 in the same as Figures 1 to 2 in the features similar to those in are given reference numerals that are 200 greater than the reference numerals of the corresponding features. In Figure 4In it, the PCB 222 is circular and thus has a single edge 232. The PCB 222 is centered on the centerline 224. Four openings 250 extend through the PCB 222 from the first side 226 to the second side (not shown). The openings 250 are symmetrically arranged around the centerline 224. Each opening 250 is circular and centered on the axis 252.

[0029] A strain relief 260 is associated with each opening 250 to help reduce or mitigate strain on the PCB 222 during attachment to a motherboard (not shown). A first slot 262 and a second slot 272 extend radially inwards from the edge 232, generally towards the centerline 224. The first slot 262 and the second slot 272 may extend parallel to each other (as shown) or extend transverse to each other (not shown). The first slot 262 and the second slot 272 may extend towards the centerline 224. In any case, the first slot 262 and the second slot 272 are positioned on opposite sides of the opening 250. A third slot 282 is radially inwards of the first slot 262 and the second slot 272 and overlaps each of the first and second slots. Thus, during connection to the motherboard, the strain induced in the tab 290 is radially outwards oriented towards the single edge 232 in a manner S2, rather than allowing it to be radially inwards towards / into the image sensor 240.

[0030] Figures 5 to 6B An exemplary electronic device 320 used in a tire pressure monitoring (TPM) sensor 300 is shown. The TPM sensor 300 includes a housing 304 and a cover 334 that cooperate to enclose the electronic device 320. Referring Figures 6A to 6B , the housing 304 defines a cavity 306 that houses a battery 310 electrically connected to the electronic device 320. Protrusions 312 extend within the cavity 306 between the sides of the housing 304 (such as the top and bottom sides as Figure 6A shown). Ribs 314 extend around the perimeter of the housing 304.

[0031] The PCB 322 in the electronic device 320 is generally rectangular and includes a first edge 330 and a second edge 332. A sensor 340 is a pressure sensor fixed to the first side 326 of the PCB 322. A compression gasket 327 is fixed to the pressure sensor 340 on the side facing away from the PCB 322. One or more strain reliefs 360 are provided on the PCB 322 adjacent to the second edge 332 to define an elastic tab 390 on the PCB 322. To this end, a third slot 382 overlaps a first slot 362 and a second slot 372 that extend to the second edge 332 of the PCB 322.

[0032] The cover 334 has the same shape as the housing 304 and defines a cavity 336. The contact support 338 extends from the lower side of the cover 334 into the cavity 336 at a predetermined position. The contact support 338 may be integrally formed with or fixed to the cover 334. The rib 344 extends around the perimeter of the cover 334 for mating with the rib 314 on the housing 304.

[0033] To assemble the TPM sensor 300, the electronic device 320 is placed within the cavity 306 to support it within the housing 304 by way of the protrusions 312 and the compression gasket 327. Accordingly, the pressure sensor 340 and the gasket 327 are located between the PCB 322 and the housing 304. The second side 328 of the PCB 322 faces away from the housing 304. The cover 344 is placed on the housing 304 and the ribs 314, 344 engage with each other. As a result, the contact support 338 aligns with and engages the tab 390 on the PCB 322, thereby inducing strain therein. The ribs 314, 344 are laser welded together to securely enclose the electronic device 320 between the housing 304 and the cover 334. Due to the elastic properties of the tab 390 provided by the strain relief 360, the tab redistributes the strain induced by the contact support 338 engaging the tab 390 to the second edge 332 of the PCB 322 and away from the pressure sensor 340 and other components on the PCB.

[0034] An advantage of the electronic device described herein is that it redistributes high strain regions in the PCB, where there are local connections to other electronic components, from paths pointing to the electronic components (such as sensors) to paths away from the electronic components. This redistribution not only helps prevent excessive strain on the electronic components, but also helps prevent excessive strain on any solder that may be present on the PCB. Accordingly, a secure connection can be provided between the electronic device and any components fixed thereto while maintaining the integrity of the electronic components and the solder.

[0035] What has been described above are examples of the present invention. Of course, it is not possible to describe all conceivable combinations of components or methods for the purpose of describing the present invention, but one of ordinary skill in the art will recognize that many further combinations and permutations of the present invention are possible. Accordingly, the present invention is intended to cover all such alterations, modifications, and variations that fall within the spirit and scope of the appended claims.

Claims

1. An electronic device, comprising: A printed circuit board, the printed circuit board including at least one edge and a strain relief member, the at least one edge including a first edge and a second edge extending transversely to each other, the strain relief member including a first groove, a second groove, and a third groove, the first groove extending away from the first edge, the second groove extending away from the second edge, wherein, in the extending direction of the first groove, the first groove overlaps with the third groove and the second groove is spaced apart from the third groove, and in the extending direction of the second groove, the second groove overlaps with the third groove and the first groove is spaced apart from the third groove, the first groove, the second groove, and the third groove cooperate with the at least one edge to define an elastic tab for redistributing the strain induced in the printed circuit board; and A sensor, the sensor being disposed on the printed circuit board such that the strain relief member redistributes the strain away from the sensor.

2. The electronic device according to claim 1, wherein The The third groove overlaps with the first groove and the second groove to form the elastic tab.

3. The electronic device according to claim 2, further comprising an opening extending through the printed circuit board and positioned on the elastic tab for receiving a fastener to secure the printed circuit board to an electronic component.

4. The electronic device according to claim 3, wherein, The opening is centered on an axis, and the third groove extends circumferentially around the axis.

5. The electronic device according to claim 2, wherein, The first groove and the second groove are linear, and the third groove is arcuate.

6. The electronic device according to claim 1, wherein, The printed circuit board is circular such that the at least one edge includes a single edge surrounding a center line.

7. The electronic device according to claim 6, wherein, The first groove and the second groove extend from the single edge towards the center line; and The third groove overlaps with the first groove and the second groove to form the elastic tab.

8. The electronic device according to claim 6, further comprising an opening extending through the printed circuit board and positioned on the elastic tab for receiving a fastener to secure the printed circuit board to a substrate.

9. The electronic device according to claim 8, wherein, The opening is centered on an axis, and the third groove extends circumferentially around the axis.

10. The electronic device according to claim 6, wherein, The first groove and the second groove are linear, and the third groove is arcuate.

11. An electronic device, comprising: A printed circuit board, the printed circuit board including: a first edge and a second edge extending transversely to each other; and a strain relief member, the strain relief member including a plurality of grooves, the plurality of grooves cooperating with the first edge and the second edge to define an elastic tab, the plurality of grooves including: A first groove extending away from the first edge; A second groove extending away from the second edge; and A third groove overlapping with the first groove and the second groove to form the elastic tab; and A sensor disposed on the printed circuit board such that the strain relief member redistributes the strain away from the sensor, Wherein, in the extending direction of the first groove, the first groove overlaps with the third groove and the second groove is spaced apart from the third groove; in the extending direction of the second groove, the second groove overlaps with the third groove and the first groove is spaced apart from the third groove.

12. The electronic device according to claim 11, wherein, The first edge and the second edge extend transversely to each other, the first groove extends from the first edge, and the second groove extends from the second edge.

13. The electronic device according to claim 11, further comprising an opening that extends through the printed circuit board and is positioned on the elastic tab for receiving a fastener to fix the printed circuit board to an electronic component.

14. The electronic device according to claim 13, wherein, The opening is centered on an axis, and the third groove extends circumferentially around the axis.

15. The electronic device according to claim 11, wherein, The first groove and the second groove are linear, and the third groove is arc-shaped.

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