WO2011095904A1

WO2011095904A1 - Methods and devices for incorporating passive noise-filtering components into enclosures of electronic products

Info

Publication number: WO2011095904A1
Application number: PCT/IB2011/050179
Authority: WO
Inventors: Aly Aboulnaga; Robert Miller
Original assignee: Koninklijke Philips Electronics N.V.
Priority date: 2010-02-02
Filing date: 2011-01-14
Publication date: 2011-08-11
Also published as: EP2532091A1; TW201206333A

Abstract

The present disclosure is directed to inventive methods and apparatus for an integrated electronics filter where a ferrite bead is partially enclosed in a grommet. The grommet is connected an electronics enclosure in a location that enables compact arrangement of parts in an electronic product. At least one wire from a wire harness is passed through an opening in the ferrite bead and the grommet to be attached to a circuit board disposed within the electronics enclosure.

Description

Methods and Devices for Incorporating Passive Noise-Filtering Components into

Enclosures of Electronic Products

Technical Field

[0001] The present invention is directed generally to packaging of electronic components. More particularly, various inventive methods and apparatus disclosed herein relate to incorporating passive noise-filtering components into enclosures for electronic products.

Background

[0002] A ferrite bead is a passive component used to filter or suppress high frequency noise in electronic circuits. Ferrite beads employ dissipation of high-frequency currents in a ferrite to implement a high-frequency noise suppression device. Typically, filtering of noise via ferrite beads is accomplished by placing them around a portion of one or more wires supplying alternating current (AC) or direct current (DC) power to circuit boards of an electronics product. Ferrite beads are often soldered to the circuit boards, occupying a relative large area due to their size relative to other electronic components on the boards. Ferrite beads may also be placed on some or all of the wires of a wire harness away from the circuit boards. That positioning of the ferrite bead, however, typically produces an awkward "lump" in the wire harness, potentially making it difficult to thread the wire harness through holes or conduits. Positioning the ferrite bead on the wire harness may also require the expense and complexity of a separate enclosure to protect the ferrite bead. Thus, there is a need in the art to position ferrite beads within the enclosure of an electronics product, yet avoid consuming valuable space on a circuit board.

[0003] Circuit boards of electronics products are often encased in an enclosure for providing protective and/or decorative housing for electronics product. Grommets may be used to allow some or all of the wires of a wire harnesses to penetrate the walls of enclosures without being subject to abrasion or kinking that would occur should the wires be allowed to directly contact the walls of the enclosure. Summary

[0004] Applicants have recognized and appreciated that it would be beneficial to combine a ferrite bead with a grommet thus freeing valuable space on a circuit board. That arrangement would allow the bulky ferrite bead to occupy a void within the enclosure instead of the more valuable space on the circuit board thereby providing a more compact electronics product.

[0005] Accordingly, the present disclosure is directed to inventive methods and apparatus for a integrating a grommet, a ferrite bead and a wire harness into an enclosure of an electronics product. Generally, in one aspect, the invention relates to an electronic noise- filtering component that includes a grommet defining a chamber and a ferrite bead at least partially disposed within the chamber, the ferrite bead defining an opening therethrough for receiving at least one wire. The grommet may be formed from at least two parts or sides joinable together to form the chamber. The grommet may also include at least one tab for securing the ferrite bead within the chamber.

[0006] In another aspect, the invention generally relates to an electronic device including at least one circuit board disposed in an enclosure having a wall, further including at least one wire connected to the circuit board; a grommet attached to the enclosure and defining a chamber; and, a ferrite bead at least partially disposed within the chamber, the ferrite bead defining an opening therethrough for passing the wire from the circuit board out of the enclosure. The grommet defines at least one slot for attachment thereof to the wall of the enclosure. The grommet may be formed from at least two parts or sides joinable together to form the chamber. The grommet may also include at least one tab for securing the ferrite bead within the chamber. In various embodiments, the ferrite bead may be formed as single item with a single opening for a portion of the wire harness. In some embodiments, a portion of the wire harness may pass through the opening in the ferrite bead one time. In some embodiments a portion of the wire harness will pass through the opening more than one time to form one or more wire turns around the ferrite bead. The chamber of the grommet may be constructed to accommodate one or more wire turns. [0007] The ferrite bead may also be formed of two more parts in a split configuration. The multiple parts of the bead may be arranged by the chamber of the grommet to form an opening for a portion of the wire harness. The parts of the ferrite bead may be electrically isolated from each other by the construction of the grommet. In some embodiments a portion of the wire harness may pass through the opening in the ferrite bead one time. In other embodiments a portion of the wire harness will pass through the opening more than one time to form one or more wire turns round the ferrite bead. The chamber of the grommet may be constructed to accommodate two or more parts of the ferrite bead.

[0008] In yet another aspect, the ferrite bead will be essentially solid and have an opening or openings that are nearly the same size as the individual wire or wires which pass through the ferrite bead. In some embodiments the wire or wires will pass through the ferrite bead more than one time forming one or more wire turns around the ferrite bead wherein each passage of the wire may be via different openings.

[0009] In some embodiments, the wires of the wire harness may pass through the grommet by entering one face of the grommet and exiting via second face of the grommet. In other embodiments the wires of the wire harness may enter and exit through the same face of the grommet.

[0010] In some embodiments, the grommet may be formed from a relatively stiff material that retains some degree of flexibility. When using such a material the grommet may be flexible enough so that it may be formed as an open arrangement such that the grommet can be folded to form the chamber which encloses the ferrite bead and while allowing a portion of the wire harness to pass through the grommet. The folded grommet may then be inserted or snapped into the enclosure.

[0011] In some embodiments, the grommet is made of rubber or any other flexible material. When using a flexible material the grommet may be formed of a single piece such that the ferrite bead and wire harness may be snapped into a chamber within the grommet. The grommet containing the ferrite bead and a portion of the wire harness may then be snapped into the enclosure. In the alternative the ferrite bead containing a portion of the wire harness may be snapped into the grommet after the grommet has been snapped into the enclosure. In yet another alternative the wire may be passed through the opening in the ferrite bead after the grommet and ferrite bead have been snapped into the enclosure.

[0012] As used herein, the term "wire harness" refers to a group of one or more individual wires. Each wire is of made of conductive material and may or may not be insulated. The wires carry alternating current (AC) or direct current (DC) to the circuit board. The wires may also carry electronic signals.

[0013] The term "grommet" is used herein to refer to an apparatus which may be designed to protect one or more wires that penetrate and electronic enclosure. The grommet may also serve to prevent damage to connection to the circuit board when the wire or wires are pulled upon. This function is often referred to as "strain relief".

[0014] The ferrite bead may be a single piece component with one or more openings dimensioned for passing wires from the wire harness through the ferrite bead. The opening may allow the easy passage of the wire a single time or allow the wire to pass through the opening several times. The ferrite bead may also include two or more parts which are arranged to form a single opening suitable for easily passing wires from the wire harness though the ferrite bead. The parts may or may not be separated from each other by an insulating material. Although the figures show a circular cross section for several embodiments of the ferrite bead other embodiments include alternate cross sections e.g. square or rectangular. Likewise the figures show a circular cross section for the openings in several embodiments of the ferrite bead, other embodiments include alternate cross sections e.g. square or rectangular

[0015] The term "snapped" means forcing a portion of an article through an opening in a rigid object that is slightly larger than the opening. Forcing the article through the opening is not destructive since the article is comprised of material the bend or fold in a manner that will allow a portion of the article to pass through the opening without damaging the article. After a portion of the article has been forced through the opening that portion will expand or unfold so that portion of the article is again larger than the opening. The portion of the article that did not pass through the opening is also larger than the opening. The result of the forcing procedure i.e. "snapping" is retention of the article in the opening in the rigid object. As an example the flexible object may be a plastic part with a foldable portion and a rigid portion. The rigid object may be a sheet metal enclosure with a circular opening. The snapping procedure will fix the plastic part the sheet metal enclosure.

[0016] The term "enclosure" means a chamber or compartment used to enclose or partially enclose at least a circuit board. The enclosure may be made of relatively thin material comprised of metal or plastic. The enclosure may have opening which allow the passage of wires of a wire harness to the interior of the chamber and connect to the circuit board.

[0017] It should be appreciated that all combinations of the foregoing concepts and additional concepts discussed in greater detail below (provided such concepts are not mutually inconsistent) are contemplated as being part of the inventive subject matter disclosed herein. In particular, all combinations of claimed subject matter appearing at the end of this disclosure are contemplated as being part of the inventive subject matter disclosed herein. It should also be appreciated that terminology explicitly employed herein that also may appear in any disclosure incorporated by reference should be accorded a meaning most consistent with the particular concepts disclosed herein.

Brief Description of the Drawings

[0018] In the drawings, like reference characters generally refer to the same parts throughout the different views. Also, the drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention.

[0019] FIG. 1 illustrates a grommet in the prior to folding with a ferrite bead.

[0020] FIG. 2 illustrates the grommet and ferrite bead of FIG. 1 with an enclosure, a circuit board and a wire.

[0021] FIG. 3 illustrates grommet and ferrite bead of FIG. 1 where the grommet is in the folded position and has been inserted into an opening in the enclosure where the wire passes through the opening in the ferrite bead.

[0022] FIG. 4 illustrates a close-up view of the grommet of FIG 3.

[0023] FIG. 5 illustrates a second embodiment of a grommet in the open position and a split ferrite bead. [0024] FIG. 6 illustrates a second embodiment of a grommet in the open position and a split ferrite bead.

[0025] FIG. 7 illustrates a second embodiment of a grommet in the open position and a split ferrite bead.

[0026] FIG. 8 illustrates a second embodiment of a grommet in the open position and a split ferrite bead.

Detailed Description

[0027] Applicants have recognized and appreciated that it would be beneficial to combine a ferrite bead with a grommet thus freeing the circuit board area that would be occupied by the ferrite bead. Combining the ferrite bead with a grommet would allow the bulky ferrite bead to occupy a void within the enclosure instead of the more valuable space on the circuit board thus permitting a more compact electronics product.

[0028] In the following detailed description, for purposes of explanation and not limitation, representative embodiments disclosing specific details are set forth in order to provide a thorough understanding of the claimed invention. However, it will be apparent to one having ordinary skill in the art having had the benefit of the present disclosure that other

embodiments according to the present teachings that depart from the specific details disclosed herein remain within the scope of the appended claims. Moreover, descriptions of well-known apparatuses and methods may be omitted so as to not obscure the description of the representative embodiments. Such methods and apparatuses are clearly within the scope of the claimed invention. For example, various embodiments of the approach disclosed herein are particularly suited for a rectangular enclosure containing a single circuit board powered by a wire harness comprised of a single wire. Accordingly, for illustrative purposes, the claimed invention is discussed in conjunction with such a configuration. However, other configurations and applications of this approach are contemplated without deviating from the scope or spirit of the claimed invention.

[0029] Referring to FIG. 1, a ferrite bead 100 having an opening 101 is shown prior to placement within a folding grommet 110 according to various embodiments of the invention. Folding grommet 110 is shown in an unfolded position includes two component parts or sides 111a and 111b. Sides 111a and 111b may have slots 112a (not shown) slot 112b respectively. The two sides 111a and 111b may be joined, for example, folded together to secure ferrite bead 100 within a chamber 115 formed therebetween. One side of the chamber 115 may include a wall section, which forms an opening 114, when the folding grommet 110 is folded, for enabling a wire or wires to pass through the folding grommet 110 and the ferrite bead 100 but preventing the ferrite bead 100 to fall out of chamber 115. Another side of the chamber has two tabs 113a and 113b for securing the ferrite bead within the chamber 115. Tab 113a may be attached to side 111a of the folding grommet. Tab 113b may be attached to side 111b of the folding grommet.

[0030] In various embodiments of the invention, the ferrite bead is formed from a magnetic ceramic material, e.g. manganese-zinc compositions (Mn_aZn₍i-a₎Fe₂0₄) or nickel-zinc

compositions (Ni_aZn₍i-a₎Fe₂0₄). However, any ferrite material that filters or suppresses high frequency noise in electronic circuits by dissipating high-frequency currents may be used, as well.

[0031] Referring to FIG. 2, an embodiment of a folding grommet 210 and ferrite bead 200 is shown prior to attachment to an enclosure 220 of an electronic device. Enclosure 220 contains opening 240 which may be shaped to accommodate folding grommet 210 when folding grommet 210 is in the folded position. Enclosure 220 contains one or more circuit boards 250 connected to wire 230.

[0032] Referring to FIG. 3, an embodiment of a folding grommet 310 is shown after folding and attaching to an enclosure 320. Folding grommet 310 encloses ferrite bead 300 which in turn may enclose a portion of wire 330 connected to a circuit board 350.

[0033] Referring to FIG. 4, an embodiment of a folding grommet 410 is shown after folding and attachment to an enclosure 420. Folding grommet 410 may be secured to enclosure 420 with slots 412a and 412b. Slots 412a and 412b may be shaped to accommodate the thickness of the walls that make up enclosure 420. Folding grommet 410 may enclose ferrite bead 400 which in turn may enclose a portion of wire 430. Ferrite bead 400 may be secured within chamber 415 by tabs 413a and 413b.

[0034] Referring to FIG. 5, an embodiment of a split ferrite bead 590 is shown prior to placement within a split folding grommet 510. Split ferrite bead 590 may include two parts 592a and 592b. Ferrite halves 592a and 592b may have a semi- toroidal cross-section.

[0035] Split folding grommet 510 is shown in an unfolded position may include two sides 511a and 511b. Side 511a and 511b may have slots 512a (not shown) slot 512b respectively. The two sides 511a and 511b may be folded together to secure ferrite parts 592a and 592b within a chamber halves 519a and 519b respectively. Each chamber half 519a and 519b may be comprised of wall section which form an opening 514, when the split folding grommet 510 is folded, which permits a wire or wires to pass through the split folding grommet 510 and the split ferrite bead 590 but does not permit the ferrite parts 592a and 592b to fall out of chamber halves 519a and 519b. Another side of the chamber has two semi-circular loops 117a and 117b which may secure the respective ferrite parts 592a and 592b within the respective chamber halves 519a and 519b. Chamber half 515a may also comprise a wall 516 which may be shaped to separate the ferrite parts 592a and 592b from each other. Separation of the ferrite parts 592a and 592b may be arranged at single point between the ferrite parts 592a and 592b or a several points depending on the configuration of the ferrite parts 592a and 592b within the chamber halves 519a and 519b.

[0036] Referring to FIG. 6, an embodiment of a ferrite bead 600 is shown with an opening 601 which encloses a portion of a wire 603. The wire 603 may pass through the opening 601 and may then pass on the outside of ferrite bead 600 before passing another time through the opening 601 thus forming a turn e.g. 604a. The wire 603 may also form multiple turns e.g. 604a, 604b. Wire 603 may form any number of turns within the scope of the invention.

[0037] Referring to FIG. 7, an embodiment of a multiple opening ferrite bead 700 is shown with openings 701a, 701b and 701c. A wire or multiple wires may pass through some or all of the openings 701a-701c. A single wire may pass through each of the openings 701a-701c forming turns as described above in relation to the ferrite bead 600 in FIG. 6. Multiple wires may pass through a single opening e.g. 701a, or through different openings 701a-701b. Any wire may pass through a single opening e.g. 701a multiple times forming turns as described above with relation to the ferrite bead 600 in FIG. 6

[0038] Referring to FIG. 8, an embodiment of a one-piece grommet 810 is shown. One-piece Grommet 810 may be comprised of rubber or any other similarly flexible material. Grommet 818 defines a chamber 815, and includes lips 818a and 818b for securing one-piece grommet 810 to an enclosure by compressing one-piece grommet 810 so that it will snap into a suitable opening in a wall of an enclosure. When one-piece grommet 810 is in place lip 818a will be on one side of the wall of the enclosure and lip 818b will be on the other side of the wall of the enclosure. The distance between the lips 818a and 818b may be shaped to accommodate the thickness of the walls that make up the enclosure

[0039] One-piece grommet 810 may also include tabs 813a-813f formed in two groups of three 813a-813c, 813d-813f. One group of tabs e.g. 813a-813c may be formed at one end of chamber 815 and the other group of tabs e.g. 813d-813f may be formed at the other end of chamber 815. A ferrite bead may be secured within chamber 815 by my forcing the ferrite bead past one group of tabs (i.e. snapping the ferrite bead into place) e.g. 813a-813c, to position the ferrite bead between the two groups of tables 813a-813c, 813d-813f. One group of tables e.g. 813d-813f, may be replaced by a wall with an opening at either end chamber 815.

[0040] Other configurations of a folding grommet are possible such as grommets that include more than one side or sides that have more than one slot or no slots at all. Slots on the grommet sides may be replaced or augmented by latches designed to be forced through an opening in an enclosure and thereby be fixed or snapped in place. Other known methods may be used to secure the grommet to the enclosure. A single tab may be used to secure the ferrite bead within the chamber or multiple tabs may be used. Both sides of the chamber may have tabs to secure the ferrite bead within the chamber. Other configurations of tabs or walls with holes may be used to secure the ferrite bead within the chamber. In one alternative configuration the ferrite bead may be glued to the grommet. [0041] Split ferrite parts may be secured in chamber halves with loops tabs or walls.

Chamber halves may be constructed so that the ferrite halves come into contact with each other when the folding grommet is folded or positioned by the shape of the chamber halves in manner that prevent contact between the ferrite parts. Separation of the ferrite parts by the construction of the chamber halves may be accomplished by means of walls, tabs or other mechanical separation shapes.

[0042] Ferrite beads may be constructed of a single piece or of several parts. The ferrite pieces may be accomplished by an even division into two parts or into multiple parts of nonuniform size. In each case assembly of the ferrite parts will result in one or more openings for the passage of a wire or wires

[0043] Ferrite beads may be constructed to comprise a single opening or several opening for the passage of wires. A wire may pass through the ferrite bead a single time or several times. One wire from a wire harness may pass through the opening in the ferrite bead or several wires or all of the wires of a wire harness may pass through the opening.

[0044] While several inventive embodiments have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and/or structures for performing the function and/or obtaining the results and/or one or more of the advantages described herein, and each of such variations and/or modifications is deemed to be within the scope of the inventive embodiments described herein. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and/or configurations will depend upon the specific application or applications for which the inventive teachings is/are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific inventive embodiments described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto, inventive embodiments may be practiced otherwise than as specifically described and claimed. Inventive embodiments of the present disclosure are directed to each individual feature, system, article, material, kit, and/or method described herein. In addition, any combination of two or more such features, systems, articles, materials, kits, and/or methods, if such features, systems, articles, materials, kits, and/or methods are not mutually inconsistent, is included within the inventive scope of the present disclosure.

[0045] All definitions, as defined and used herein, should be understood to control over dictionary definitions, definitions in documents incorporated by reference, and/or ordinary meanings of the defined terms.

[0046] The indefinite articles "a" and "an," as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean "at least one." The phrase "and/or," as used herein in the specification and in the claims, should be understood to mean "either or both" of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Multiple elements listed with "and/or" should be construed in the same fashion, i.e., "one or more" of the elements so conjoined. Other elements may optionally be present other than the elements specifically identified by the "and/or" clause, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, a reference to "A and/or B", when used in conjunction with open-ended language such as "comprising" can refer, in one embodiment, to A only (optionally including elements other than B); in another embodiment, to B only (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc.

[0047] Reference numerals, if any, are provided in the claims merely for convenience and are not to be read in any way as limiting.

[0048] As used herein in the specification and in the claims, the phrase "at least one," in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase "at least one" refers, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, "at least one of A and B" (or, equivalently, "at least one of A or B," or, equivalently "at least one of A and/or B") can refer, in one embodiment, to at least one, optionally including more than one, A, with no B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc.

Claims

1. An electronic noise-filtering component, comprising:

a grommet defining a chamber; and,

a ferrite bead at least partially disposed within the chamber, the ferrite bead defining an opening therethrough for receiving at least one wire.

2. The electronic noise-filtering component of claim 1, wherein the grommet comprises at least two sides joinable together to form the chamber.

3. The electronic noise-filtering component of claim 1, wherein the grommet comprises at least one tab for securing the ferrite bead within the chamber.

4. An electronic device including at least one circuit board disposed in an enclosure having a wall, the device comprising:

at least one wire connected to the circuit board;

a grommet attached to the enclosure and defining a chamber; and, a ferrite bead at least partially disposed within the chamber, the ferrite bead defining an opening therethrough for passing the wire from the circuit board out of the enclosure.

5. The electronic noise filter packaging system of claim 4, wherein the grommet defines at least one slot for attachment thereof to the wall of the enclosure.

6. The electronic noise-filtering component of claim 4, wherein the grommet comprises at least two sides joinable together to form the chamber.

7. The electronic noise-filtering component of claim 4, wherein the grommet comprises at least one tab for securing the ferrite bead within the chamber.