Heat sink attachment

[0001] Attached to an electrical component mounted to a circuit board in one design of a computer is a heat sink that serves to draw heat from the electrical component and dissipate the heat into the environment. Fasteners serve to attach the heat sink to the electrical component. The fasteners comprise two metal clips. The electrical component comprises a microprocessor. A firm connection of the two metal clips with the circuit board and the heat sink serves to press the heat sink against the microprocessor.

[0002] The metal clips serve to hold and center the heat sink firmly against the microprocessor to effect mounting and thermal conductivity. So, the design requires the clips to be large and therefore comprise relatively large quantities of metal. In addition, the firm connection of the metal clips to the circuit board as well as the metallic abutment of the clips with the heat sink allow vibration and shock imparted to the circuit board to be transmitted to, and possibly dislodge, the heat sink and consequently damage the microprocessor and/or other electrical components.

[0003] Features of exemplary implementations of the invention will become apparent from the description, the claims, and the accompanying drawings in which:

[0004] FIG. 1 is a top, perspective representation of one side of an exemplary implementation of an apparatus that comprises a circuit board, one or more electrical components, one or more heat sinks, and one or more clips.

[0005] FIG. 2 is a top, perspective representation of another side of the apparatus of FIG. 1.

[0006] FIG. 3 is a top representation of the apparatus of FIG. 1.

[0007] FIG. 4 is a side representation of the apparatus of FIG. 1.

[0008] FIG. 5 is one perspective representation of one of the heat sinks and a pair of the clips of the apparatus of FIG. 1.

[0009] FIG. 6 is another perspective representation of the heat sink and the pair of clips of the apparatus of FIG. 5, and illustrates one or more adhesives located on a face of the heat sink.

[0010] FIG. 7 is an enlarged, perspective representation of one of the clips of the apparatus of FIG. 1.

[0011] FIG. 8 is a partial, enlarged, top representation of a region of one of the heat sinks and one of the clips of the apparatus of FIG. 3 indicated by line 8-8 therein.

[0012] FIG. 9 is a bottom representation of the region of FIG. 8.

[0013] FIG. 10 is a top, perspective representation of the region of FIG. 8.

[0014] FIG. 11 is a bottom, perspective representation of the region of FIG. 8.

[0015] FIG. 12 is a partial, enlarged, perspective representation of a region of the circuit board, one of the electrical components, one of the heat sinks, and one of the clips of the apparatus of FIG. 2 indicated by line 12-12 therein.

[0016] FIG. 13 is a bottom, perspective representation of the one side the apparatus of FIG. 1.

[0017] FIG. 14 is a partial, enlarged, perspective representation of a region of the circuit board, one of the electrical components, one of the heat sinks, and one of the clips of the apparatus of FIG. 13 indicated by line 14-14 therein.

[0018] Turning to FIG. 1, an apparatus 100 in one example comprises one or more adhesives that serve to provide at least primary attachment of a heat sink with one or more electrical components coupled with a circuit board. The apparatus 100 in one example includes a plurality of components such as computer hardware components. A number of such components can be combined or divided in one example of the apparatus 100. The apparatus 100 in one example comprises any (e.g., horizontal, oblique, or vertical) orientation, with the description and figures herein illustrating one exemplary orientation of the apparatus 100, for explanatory purposes.

[0019] Referring to FIG. 1, the apparatus 100 comprises a circuit board 102, one or more electrical components 104, one or more adhesives 602 (FIG. 6), one or more heat sinks 106, and one or more clips 108. In one example, the circuit board 102 comprises a printed circuit board (PCB). The circuit board 102 serves to support a number of items, for example, the electrical components 104 and electrical connections (not shown) between the electrical components 104. The circuit board 102 supports one or more of the electrical components 104 having one or more of the heat sinks 106 attached thereto. In addition, the circuit board 102 supports one or more of the electrical components 104 lacking attachment to any of the heat sinks 106. A subset or all of the electrical components 104 are coupled with each other on the circuit board 102.

[0020] Referring to FIGS. 1 and 3-4, the circuit board 102 comprises passages 302, 304, 306, and 308 and major faces 402 and 404. In one example, the passages 302, 304, 306, and 308 comprise openings that extend between the major faces 402 and 404. The passages 302, 304, 306, and 308 receive respective arms of the clips 108 extending between the major faces 402 and 404. The passages 302, 304, 306, and 308 serve to cooperate with the clips 108 to hold the heat sink 106 in place atop the electrical component 104 while the adhesive 602 solidifies to attach the heat sink 106 to the electrical component 104, as described herein.

[0021] The major faces 402 and 404 comprise surface areas that are larger than any other faces of the circuit board 102. In addition, the major face 402 comprises a top or component side of the circuit board 102. The major face 402 serves to support the electrical components 104, for example, in engagement with the clips 108. The major face 404 serves to support electrical interconnection of the electrical components 104, for example, by supporting printed circuit traces (not shown) located on the major face 404. In one example, the major face 404 comprises a trace or print side of the circuit board 102. In a further example, the major face 404 comprises a surface that abuts the ends of the clips 108.

[0022] Again referring to FIG. 1, the electrical components 104 superimpose the major face 402 of the circuit board 102. The electrical component 104 comprises a component of electrical circuitry on the circuit board 102. In one example, the electrical component 104 comprises a computer microprocessor. In another example, the electrical component 104 comprises a transistor, resistor, or capacitor. The electrical components 104 are electrically and mechanically coupled with the circuit board 102.

[0023] The heat sink 106 superimposes the major face 402 of the circuit board 102. The heat sink 106 serves to draw heat away from one or more of the electrical components 104. The heat sink 106 in one example comprises one or more metals, for example, aluminum extrusion. One or more attachments serve to couple the heat sink 106 with one or more of the electrical components 104. In one example, referring to FIGS. 1 and 6, one or more of the adhesives 602 serve to provide at least primary attachment of the heat sink 106 with one or more of the electrical components 104, as described herein.

[0024] The heat sink 106 comprises a base 110, a plurality of fins 112, one or more engagement portions, for example, engagement portions 310 (FIG. 3) and 312 (FIG. 3), and a face 604 (FIG. 6). The base 110 serves to provide a mechanical support and/or connection structure for the adhesive 602 and the fins 112. In addition, the base 110 serves to provide a thermal drainage path from the electrical component 104 and the adhesive 602 to the fins 112.

[0025] The fins 112 serve to transfer, to ambient air, heat conducted from the electrical component 104 and through the adhesive 602 and the base 110, and/or from the electrical component 104 and through the base 110 alone. The fins 112 are spaced apart and extend away the electrical component 104. In one example, the fins 112 serve to allow convective cooling by the air to remove heat conducted to the surface of the fins 112. In a further example, a fan (not shown) serves to enhance the convective cooling by forcing quantities of air past the fins 112 for heat removal. In a still further example, the fins 112 serve to promote development of temperature gradients that cause thermal conduction of heat along the length of the fins 112 away from the electrical component 104 for cooling thereof.

[0026] Referring to FIG. 3, the engagement portions 310 and 312 serve to engage one or more portions of the clips 108. Referring to FIGS. 3 and 9, the engagement portion 312 comprises walls 902 and 904 and recesses 906 and 908. The walls 902 and 904 define one or more portions of the recesses 906 and 908. The recesses 906 and 908 serve to receive one or more portions of the clips 108, for example, to securely connect the clips 108 with the heat sink 106. In one example, one or more portions of the clip 108 are crimped against one or more of the walls 902 and 904.

[0027] Referring to FIGS. 1 and 6, the face 604 is coupled with the electrical component 104 to draw heat therefrom to the fins 112. The adhesive 602 in one example serves to indirectly couple a portion of the face 604 with the electrical component 104. In a further example, a portion of the face 604 directly contacts the electrical component 104.

[0028] The adhesive 602 is located between the electrical component 104 and the heat sink 106. In one example, the adhesive 602 covers and/or coats a portion of the face 604 of the heat sink 106 for attachment with the electrical component 104. In another example, the adhesive 602 covers and/or coats a portion of a face of the electrical component 104 for attachment with the heat sink 106. In a further example, the adhesive 602 comprises a pressure-sensitive adhesive that serves to form a bond when placed under pressure. In a still further example, the adhesive 602 comprises a thermally-conductive material that serves to conduct heat from a portion of the electrical component 104 to the heat sink 106. The adhesive 602 in one example comprises a material offered by Chomerics, Division of Parker Hannifin Corporation (77 Dragon Court, Woburn, Mass., 01888-4014, www.chomerics.com), under the trade identifier T-410.

[0029] The adhesives 602 in one example serve to provide at least primary attachment of the heat sink 106 with one or more of the electrical components 104. In a further example, the adhesives 602 serve to promote thermal conductivity between the electrical components 104 and the heat sink 106. One or more of the adhesives 602 serve to conduct heat from one or more portions of the electrical components 104 to the heat sink 106. In another example, the adhesives 602 serve to conduct heat from a first portion of the electrical component 104 to the heat sink 106, where a second portion of the electrical component 104 directly contacts and transfers heat to the heat sink 106. In a still further example, the adhesive 602 serves to absorb a portion of one or more vibrations.

[0030] Vibrations can potentially reach the circuit board 102 before and/or after assembly. The vibrations can comprise repetitive patterns and/or sudden shocks. In one example, a vehicle employed for transportation of the circuit board 102 encounters vibrations that the vehicle transmits to the circuit board 102. In another example, an individual handling and/or operating the apparatus 100 or a portion thereof transmits vibrations to the circuit board 102.

[0031] In one example, the vibrations are transmitted along the circuit board 102 to the electrical component 104. In another example, the vibrations are transmitted over the circuit board 102, through the clip 108, and to the heat sink 106. The adhesive 602 serves to absorb a portion of the vibrations. The adhesive 602 absorbs a portion of one or more vibrations transmitted to the adhesive 602 from the electrical component 104 and/or a portion of one or more vibrations transmitted to the adhesive 602 from the clip 108 and the heat sink 106. One or more of the vibrations in one example experience dampening and/or decay before reaching the adhesive 602, for example, owing to friction encountered during transmission through the circuit board 102 and the electrical component 104 or the clip 108 and the heat sink 106.

[0032] The adhesive 602 absorbs an amount of the vibrations effective to avoid compromising the attachment of the heat sink 106 and the electrical component 104. In a further example, the adhesive 602 serves to prevent vibration of the clip, for example, at a harmonic frequency out of phase with the circuit board 102 and/or the heat sink 106. The adhesive 602 serves to promote maintenance of the attachment of the heat sink 106 and the electrical component 104. By absorbing the portion of the vibrations, the adhesive 602 serves to prevent the portion of the vibrations from loosening the attachment between the electrical component 104 and the heat sink 106. So, the heat sink 106 continues to perform cooling of the electrical component 104. In addition, the adhesive 602 serves to prevent the heat sink 106 from becoming free from the electrical component 104. The adhesive 602 therefore serves to avoid potential harm (e.g., impact) that otherwise could befall one or more other portions of the apparatus 100 upon separation of the heat sink 106 from the electrical component 104.

[0033] The adhesive 602 serves to provide at least a primary mechanical connection between the electrical component 104 and the heat sink 106. The adhesive 602 serves to bond and/or securely join a portion of the face 604 of the heat sink 106 to a portion of the electrical component 104. In one example, the adhesive 602 comprises an adhesive of substantially uniform consistency. In another example, the adhesive 602 comprises a plurality of adhesives 602. The plurality of adhesives 602 in one example are applied contemporaneously. In another example, the plurality of adhesives 602 are applied successively. In a further example, the plurality of adhesives 602 are applied in any of a variety of relative positions. For example, one employment of multiple adhesives 602 serves to combine superior bonding strength of one adhesive 602 with superior thermal conductivity of another adhesive 602.

[0034] The at least primary attachment of the electrical component 104 and the heat sink 106 by the one or more adhesives 602 dominates any other attachment of the electrical component 104 and the heat sink 106. Upon solidification of the adhesive 602, the clips 108 need not participate or contribute in the secure mechanical connection between the electrical component 104 and the heat sink 106. After solidification of the adhesive 602 between the electrical component 104 and the heat sink 106, the clips 108 in one example are removable from the heat sink 106 and the circuit board 102 without compromise to the secure mechanical connection between the electrical component 104 and the heat sink 106. In another example, the adhesive 602 is dominant over yet still cooperates with the clips 108 in attachment of the electrical component 104 with the heat sink 106. The strength of the attachment of the electrical component 104 and the heat sink 106 contributed by the one or more adhesives 602 dominates a strength of attachment contributed by one or more of the clips 108. For example, the strength of the attachment provided by the adhesive 602 is far greater than the strength of any attachment provided by one or more of the clips 108.

[0035] Referring to FIGS. 3 and 6-7, the clip 108 serves to hold the heat sink 106 in position while the adhesive 602 bonds the heat sink 106 to the electrical component 104. For example, the passages 302, 304, 306, and 308 cooperate with the clips 108 to hold the heat sink 106 at one or more target locations relative to the electrical component 104 while the adhesive 602 solidifies to attach the heat sink 106 to the electrical component 104. The target location in one example comprises a relative location between the face 604 and the electrical component 104. With the adhesive 602 in one example freshly applied to the face 604, the heat sink 106 is positioned at the target location to allow formation and solidification of a bond by the adhesive 602 between the face 604 and the electrical component 104.

[0036] The clip 108 in one example comprises stainless steel. In one example, the clip 108 comprises a unitary construction and/or integral formation. In a still further example, the clip 108 comprises an approximate thickness of 0.6 millimeters. For example, the clip 108 comprises an interface portion 702, intermediate spring portions 710 and 712, arm portions 714 and 716, and end spring portions 718 and 720.

[0037] The interface portion 702 serves to engage the heat sink 106 for force transmission to and/or from the heat sink 106. The interface portion 702 is located between the intermediate spring portions 710 and 712. When the clip 108 is installed on the heat sink 106 and the circuit board 102, the interface portion 702 and the intermediate spring portions 710 and 712 superimpose the major face 402 of the circuit board 102.

[0038] The intermediate spring portions 710 and 712 are coupled with the arm portions 714 and 716, respectively. The arm portions 714 and 716 terminate in the end spring portions 718 and 720, respectively. The intermediate spring portions 710 and 712 and the end spring portions 718 and 720 comprise a resiliency and/or tendency to bend and/or apply an opposing and/or restorative force when forced from a free state, as will be appreciated by those skilled in the art.

[0039] Referring to FIGS. 3 and 7, the interface portion 702 of the clip 108 in one example is force-transmittingly engageable with any one of the engagement portion 310 of the heat sink 106 and the engagement portion 312 of the heat sink 106. In a further example, the arm portion 714 is extendable through any one of the passage 304 in the circuit board 102 and the passage 308 in the circuit board. In a still further example, the arm portion 716 is extendable through any one of the passage 302 in the circuit board 102 and the passage 306 in the circuit board. The end spring portions 718 and 720 are abuttable with any of a plurality of locations on the major face 404 (FIG. 4) of the circuit board 102. So, an installer of the clips 108 need not worry about selection of any particular clip 108 from a pair or supply of the clips 108, since any of the clips 108 works along either side of the heat sink 106.

[0040] The interface portion 702 comprises legs 704, 706, and 708. The legs 704, 706, and 708 are engaged with the heat sink 106 in a force-transmission relationship. In one example, referring to FIG. 9, the recess 906 of the heat sink 106 receives the leg 704 of the clip 108 and the recess 908 of the heat sink 106 receives legs 706 and 708 of the clip 108. For example, the leg 704 is crimped against the wall 904 of the heat sink 106 and the legs 706 and 708 are crimped against the wall 906 of the heat sink 106 for secure attachment of the clip 108 to the heat sink 106.

[0041] Referring to FIGS. 1, 6-7, and 13-14, the end spring portions 718 and 720 in one example are configured to, upon forced abutment thereof with the major face 404 of the circuit board 102, cooperate with additional portions of the apparatus 100 to cause an expansion force to be applied at one or more of the engagement portions 310 and 312 of the heat sink 106. The expansion force comprises first components directed toward the major face 402, and second components directed in either of two generally opposite directions along the major face 402. So, the expansion force serves to promote distribution of force over the adhesive 602 and between the face 604 and the electrical component 104. In addition, the expansion force serves to promote avoidance of localized concentration of force at an isolated point of any of the adhesive 602, the face 604, and the electrical component 104. Also, the expansion force serves to promote formation of a secure and broad bond of the adhesive 602 between the face 604 and the electrical component 104, as described herein.

[0042] The end spring portions 718 and 720 are positioned, formed, and compressed to exert force against a portion of the major face 404 adjacent one of the passages 302, 304, 306, and 308. This force comprises components that serve to tend to press the end spring portions 718 and 720 generally away from a location on the major face 404 between one or more of the passages 302, 304, 306, and 308. For example, the force exerted by the end spring portion 718 against a portion of the major face 404 adjacent the passage 306 comprises a component that serves to tend to press the end spring portion 718 generally away from a central location on the major face 404 between the passages 302, 304, 306, and 308.

[0043] So, deflection of the end spring portions 718 and 720 by the major face 404 creates a tension in the clip 108 that tends to pivot the arm portions 714 and 716 outward from the interface portion 702 and pull the intermediate spring portions 710 and 712 away from the interface portion 702. The outward pull on the intermediate spring portions 710 and 712 promotes a deflection thereof away from the interface portion 702. The intermediate spring portions 710 and 712 respond by pulling outward on the interface portion 702 and creating the expansion force at the interface portion 702. The expansion force at the interface portion 702 serves to promote distribution of a force applied from the interface portion 702 to the engagement portion 310 or 312 of the heat sink 106. The distribution of the force serves to promote a more thorough and greater expanse of bonding of the adhesive 602 with the electrical component 104, for example, where the adhesive 602 has been initially applied to the face 604 of the heat sink 106.

[0044] In one example of assembly of the apparatus 100, the adhesive 602 is applied to the face 604 of the heat sink 106. The adhesive 602 is substantially centered on the face 604, for example, to promote mechanical bonding and/or thermal conductivity. In one example where multiple adhesives 602 are employed, the adhesives 602 collectively are substantially centered on the face 604. In a further example where multiple adhesives 602 are employed, one or more of the adhesives 602 are located about and/or overlap a central portion of the face 604. In another example where multiple adhesives 602 are employed, each of the adhesives 602 is substantially centered on the face 604.

[0045] With the adhesive 602 applied to the face 604, the heat sink 106 is placed on the electrical component 104 coupled with the circuit board 102. The clips 108 are coupled with the circuit board 102 and the heat sink 106 to hold the heat sink 106 in position on the electrical component 104 while the adhesive 602 forms a bond between the heat sink 106 and the electrical component 104. The clips 108 serve to ensure proper alignment of the heat sink 106 with the electrical component 104 during bonding by the adhesive 602. For example, the clips 108 serve to substantially center the face 604 on the electrical component 104.

[0046] The steps or operations described herein are just exemplary. There may be many variations to these steps or operations without departing from the spirit of the invention. For instance, the steps may be performed in a differing order, or steps may be added, deleted, or modified.

[0047] Although exemplary implementations of the invention have been depicted and described in detail herein, it will be apparent to those skilled in the relevant art that various modifications, additions, substitutions, and the like can be made without departing from the spirit of the invention and these are therefore considered to be within the scope of the invention as defined in the following claims.