ASSEMBLY WITH PRINTED CIRCUIT BOARD AND METHOD OF FIXING A PRINTED CIRCUIT BOARD

Abstract

The present disclosure relates to a housing assembly with a printed circuit board, and to a method of fixing the printed circuit board in the housing assembly. An assembly comprises a first housing portion having a first retaining element extending upwards from a base of the first housing portion. A second housing portion has a second retaining element that extends downward from a cover of the second housing portion. A printed circuit board is attachable to an open end of the first retaining element. The open end of the first retaining element is adapted to receive a distal end of the second retaining element when the first housing portion engages with the second housing portion.

Claims

1. An assembly for housing a printed circuit board comprising: a first housing portion having at least one first retaining element extending upwards from a base of the first housing portion; a second housing portion having at least one second retaining element extending downwards from a cover of the second housing portion and towards the first housing portion, wherein the first retaining element includes an open end that is adapted to receive a distal end of the second retaining element when the first housing portion engages with the second housing portion.

2. The assembly according to claim 1, wherein the engagement of the first housing portion with the second housing portion is affected through laser welding.

3. The assembly according to claim 2, wherein the open end of the first retaining element is segmented forming a rosette.

4. The assembly according to claim 1, wherein the first retaining element has a form of a hollow cavity.

5. The assembly according to claim 1, wherein a printed circuit board is attachable to the first retaining element open end.

6. The assembly according to claim 1, wherein the second retaining element is in the shape of a conical mandrel with a converging end suitable to be received in a hollow cavity of the first retaining element without touching a base of the hollow cavity.

7. The assembly according to claim 1, wherein the first retaining element approximately two-thirds of a length from the open end of the first retaining element is segmented into a number of segments.

8. The assembly according to claim 1, wherein a printed circuit board is attachable to the first retaining element open end, wherein a portion of the first retaining element is segmented into segments, and wherein the segments creep onto the printed circuit board when the first housing portion engages with the second housing portion.

9. The assembly according to claim 1, wherein the first retaining element tapers towards the base when the first housing portion engages with the second housing portion.

10. An electronic assembly comprising a housing assembly according to any of the claim 1.

11. A method for fixing a printed circuit board in a housing, the method comprising the steps of: aligning a first housing portion having a first retaining element extending upwards from a base of the first housing portion with a second housing portion having a second retaining element extending downwards from a cover of the second housing portion, wherein the printed circuit board is attachable to an open end of the first retaining element; and laser welding the cover of the second housing portion with the first housing portion; wherein the open end of the first retaining element is segmented into segments forming a rosette, and wherein the first retaining element has a form of a hollow cavity preferably a hollow cylinder.

12. The method according to claim 11, wherein the first housing portion includes walls, and wherein the walls are laser welded with the cover of the second housing portion.

13. The method according to claim 11, wherein during laser welding, a radial force is generated that fixes the PCB in the housing.

14. The method according to claim 11, wherein the second retaining element has a shape of a conical mandrel with a converging end suitable to be received in the hollow cavity without touching a base of the hollow cavity.

15. The method according to claim 11, wherein the segments of the first retaining element creep onto the PCB when the first housing portion engages with the second housing portion.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIG. 1 shows as an example, a cross-section of an arrangement of an assembly with the PCB to be fixed;

[0035] FIG. 2 shows a cross-sectional top view of the segmented first retaining element upon the PCB;

[0036] FIG. 3 shows a perspective top view of the segmented first retaining element;

[0037] FIG. 4 shows as an example of a cross-section of an alternative arrangement of an assembly with the PCB to be fixed;

[0038] FIG. 5 shows a cross-sectional top view of the segmented first retaining element upon the PCB in the alternative arrangement;

[0039] FIG. 6 shows a cross-sectional side view of a further example of an assembly according to the present invention before performing a welding step; and

[0040] FIG. 7 shows the assembly of FIG. 6 after the welding has been performed.

DETAILED DESCRIPTION

[0041] The present invention will be explained in more detail with reference to the drawings. As an example, FIG. 1 shows an assembly 100 for implementing the method according to the present disclosure. The assembly comprises of a first housing portion 101, a printed circuit board 103, and a second housing portion 104. The first 101 and the second 104 housing portions are joined by means of laser welding, and as the result of a joining process, fixing the printed circuit board. An assembly that can be made according to the present disclosure by the first housing, the second housing and the printed circuit board (PCB), which serves, for example, to accommodate and fix the PCB, in particular, for its protection, for example against environmental influences, aggressive media, and mechanical effects.

[0042] Accordingly, an effort is made to make the housing impermeable to gases, liquids or other media as an example, and to make it strong, as necessary in the case of sensor housings, particularly ones intended for use in harsh surroundings. By means of a material-integral bonding process, besides joining the joint partners the necessary impermeability and strength can also be achieved. The housing portions 101 and 104 can, as an example, be made of plastic or metal or other suitable materials, and it is also conceivable for first and second housing portions to comprise different materials.

[0043] In the housing, the PCB 103 is to be accommodated and fixed as positionally accurate as possible, for example in such manner that it can be secured against slipping or rattling and is not affected by tolerances. Furthermore, the PCB 103 should be held in an exact position, such as a specified distance away from the base of the first housing portion 101 or the cover of the second housing portion 104. To achieve such permanent fixing, in particular positionally accurate fixing unaffected by tolerances, and according to the present disclosure, a first step aligns a first housing portion 101 having a first retaining element 102 extending upwards from a base 111 of the first housing portion with a second housing portion 104 having a second retaining element 109 extending downwards from a cover of the second housing portion, wherein the PCB 103 is removably attached to an open end of the first retaining element 102. The PCB 103 is arranged in the first housing portion 101 in a provisional fixing position, although the term provisional fixing position relative to the first housing portion 101, where the PCB is placed in the first step, can also refer to a final, specified fixing position. The open end of the first retaining element is adapted to receive a distal end of the second retaining element 109 when the first housing portion 101 engages with the second housing portion 104.

[0044] The second retaining element 109 (which may also be referred to as a dome) may have a slightly tapered (i.e., conical) shape in order to facilitate introducing the second retaining element 109 between the segments of the segmented portion 107.

[0045] For this purpose, the first retaining element 102 attached to the base 111 of the first housing portion 101 is in the form of a hollow cavity 110, preferably having a cylindrical shape. The end of the first retaining element 102 distal to the base 111 of the first housing portion 101 is segmented as shown in detail in FIG. 2.

[0046] For example, the four segmented portions 107a, 107b, 107c, 107d are shown in FIG. 2 for illustrating the method of the present disclosure. These segmented portions are symmetrically arranged having a shape of a rosette around the central axis of the first retaining element 102. Approximately two-thirds of the length from the open end of the first retaining element 102 is segmented. Thus, the PCB 103 is positioned sufficiently below the open end of the first retaining element 102. The second retaining element 109 preferably has a shape of a conical mandrel with a converging end suitable for receiving the hollow cavity 110 without touching the base of the hollow cavity 110.

[0047] When the second housing portion 104 is aligned with the first housing portion 101, the second retaining element 109 on the cover of the second housing portion 104 is received in the hollow cavity 110 of the first retaining element 102 attached to the base of the first housing portion 101. The second retaining element passes through the segmented portion 107a-107d. After the alignment of the first housing portion 101 with the second housing portion 103, the two housing portions are laser welded at points 106 as shown in FIG. 1. This laser welding creates a force sufficient to push the second retaining element 109 into the hollow cavity 110 of the first housing portion 102. Moreover, in the finally mounted state, the segmented portion 107 does not touch the second housing portion 104.

[0048] Optionally, the laser impinges the glass plate 108 above the cover of the second housing portion 104 in a direction X as shown in FIG. 1.

[0049] The glass plate 108 is transparent to the laser beam. This further enhances the pressure for laser welding for joining two housing portions. Preferably, the glass plate 108 has an opening 105 adjacent to the region of the second housing portion 104, where the second retaining element 109 is located. This opening has the advantage that the second retaining element 109 works itself into the cavity 110 against the mechanical spreading resistance of the segmented portion 107. Thereby, a force vector can be achieved in the finally mounted state that is directed towards the inside (along the direction X) and is larger than the forces occurring during operation caused by the inner pressure under heating, or by vibration. Consequently, over its entire operational life, the PCB 103 will not be lifted from the seat area at the first retaining element 102.

[0050] While sliding into the cavity 110, the second retaining element 109 exerts a force on the segmented portions 107a-107d on the open end of the first retaining element 102. This force acts in the radial direction on the segmented ends 107a-107d of the first retaining element 102 and causes them to creep onto the PCB 103. Thus, the PCB is fixed in the housing.

[0051] The fixing of the PCB 103 according to the present disclosure assures that robustness of the fixation is immune to the vibrational and torsional stresses that the housing with fixed PCB will experience in use. The radially disposed segmented ends 107a-107d of the open end of the first retaining element 102 on the PCB 103, defines an optimal geometry that dissipates the mechanical and vibrational stresses that the housing experiences in operation. For instance, electronic components in vehicles are subjected to shock and vibration environments. The components must be designed accordingly. The arrangement of the PCB according to the present disclosure results in lower fatigue limits than of the arrangement of the electronic components presented in the prior art.

[0052] FIG. 3 shows a perspective top view of the segmented first retaining element 107a-107d. This figure shows clearly that the second retaining element 109 engages with the first retaining element 102 passing through the segmented portions 107a-107d of the first retaining element 102. The force created by the laser welding on the cover of the second housing portion 104 pushes the second retaining element 109 inside the first retaining element 102. In doing so, the segmented portions 107a-107d creep upon the PCB and thus fixing the PCB in the housing. The segmentation of the end of the first retaining element 102 causes the exposure to the vibrational stresses to dissipate without moving the PCB from its fixed position.

[0053] FIGS. 4 and 5 show an alternative embodiment of the present disclosure. The only differences to the previous embodiment as shown in FIGS. 1, 2, and 3 are described in the following. Otherwise, full reference is made to the preceding text.

[0054] The cover of the housing portion 204 is laser welded additionally at the junction of the second retaining element with the first retaining element. The first retaining element 202 comprises a central dome 212 to affect this welding 206. It is to be noted that even in this arrangement, it is the creeping of the segmented portions 207a-207d that fixes the PCB in the housing. The additional welding point only serves to enhance the force with which the cover pushes the second retaining element onto the first retaining element. The creeping of the segmented portion of the first retaining element is caused by the force exerted by the second retaining element on the first retaining element. Moreover, in the finally mounted state, the segmented portion 207 does not touch the second housing portion 204.

[0055] It is to be noted that the arrangement of the housing, according to the present disclosure, is designed taking into consideration the dynamic behavior of the housing under vibration loading. Excitation is transmitted to the printed circuit board by passing through the base of the first housing portion. As such, the creeping of the segmentation of the open end of the first retaining element attached to the base of the first housing portion assures that the vibrational loading is dampened, and the PCB does not move from its fixed position.

[0056] FIGS. 6 and 7 show a further advantageous example of an assembly according to the present disclosure during assembly. The arrangement corresponds to the first example shown in FIGS. 1 and 2, except for the shape of the second retaining element 309. According to this improvement, the second retaining element 309 has a conical section 314, which engages with the segmented portion 307. Thereby, the individual segments 307a-307d are forced apart more effectively. FIGS. 6 and 7 illustrate two assembly steps according to this embodiment. As shown in FIG. 6, the second housing portion 304 (which may also be referred to as a cover) is aligned with the first housing portion 301. A first plate 308 (for instance fabricated from glass) is pressed in the direction X, until a sidewall 316 blocks the further movement of the cover.

[0057] In a next step, which is illustrated in FIG. 7, the mechanical pressure is further enhanced by pressing on a second plate 318 for performing the laser welding (as indicated by the force arrows F1). The second plate 318 may, for instance, be formed from glass or any other suitable material. This additional pressure leads to an enhanced radial force acting on the segmented portion 307 as indicated by the force arrow F2. The second plate 318 advantageously has an opening 305 in the vicinity of the second retaining element 309.

[0058] It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first retaining element, component, region, layer or section discussed below could be termed a second retaining element, component, region, layer or section without departing from the teachings of the present disclosure.

[0059] Spatially relative terms, such as proximal, distal, lower, above, upper and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as below or beneath other elements or features would then be oriented above the other elements or features. Thus, the exemplary term below can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 or at other orientations), and the spatially relative descriptors used herein interpreted accordingly.

[0060] As used herein, the singular forms a, an and the are intended to include the plural forms as well, unless expressly stated otherwise. It will be further understood that the terms includes, comprises, including and/or comprising, when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will be understood that when an element is referred to as being connected or coupled to another element, it can be directly connected or coupled to the other element or intervening elements may be present. As used herein, the term and/or includes any and all combinations of one or more of the associated listed items.

[0061] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0062] It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Dimensions, types of materials, orientations of the various components, and the number and positions of the various components described herein are intended to define parameters of certain embodiments, and are by no means limiting and are merely example embodiments. Many other embodiments and modifications within the spirit and scope of the claims will be apparent to those of ordinary skill in the art upon reviewing the above description. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms including and in which are used as the plain-English equivalents of the respective terms comprising and wherein. Moreover, in the following claims, the terms first, second, and third, etc., are used merely as labels and are not intended to impose numerical requirements on their objects.

[0063] While the present disclosure has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the intent of the disclosure as defined by the appended claims. The exemplary embodiments should be considered in a descriptive sense only, and not for purposes of limitation. Therefore, the scope of the present disclosure is defined not by the above description of the invention, but by the appended claims, and all differences within the scope will be construed as being included in the present invention.

TABLE-US-00001 REFERENCE NUMERALS Reference numeral Description 100, 200, 300 Assembly 101, 201, 301 First housing portion 102, 202, 302 First retaining element 103, 203, 303 PCB 104, 204, 304 Second housing portion 105, 305 Opening 106, 206, 306 Laser welding points 107, 107a-107d Segmented portion of first retaining element 108, 208, 308 First (glass) plate 109, 209, 309 Second retaining element 110, 310 Cavity 111, 211 Base of first housing portion 212 Central dome 314 Conical section 316 Sidewall 318 Second plate