Patent Application
20110146949
1. Technical Field
The present disclosure relates generally to heat dissipation devices, and more particularly to a heat dissipation device which is configured for facilitating securing the heat dissipation device to a printed circuit board on which a heat generating element is mounted.
2. Description of Related Art
Generally, in order to ensure the normal running of an electronic device such as a central processing unit (CPU) of a personal computer, a heat dissipation device is used to dissipate heat generated by the electronic device.
A typical heat dissipation device includes a heat sink, a heat-absorbing plate, a heat pipe with two opposite ends thereof respectively connecting to the heat-absorbing plate and the heat sink, and a clip disposed on the heat pipe and the heat-absorbing plate. The heat-absorbing plate is provided for contacting the electronic device and absorbing heat therefrom. The heat pipe is utilized to transfer heat from the heat-absorbing plate to the heat sink. Securing holes are defined in two ends of the clip, for fasteners to pass therethrough in order to fix the heat dissipation device onto the electronic device. Usually the clip and the heat pipe and the heat-absorbing plate are combined together by soldering or riveting for facilitating assembling the heat dissipation device on the electronic device. However, such a fixing mechanism has shortcomings such as high cost and lack of flexibility. There is a risk that the clip will be fixed in an inaccurate position in which the clip is not able to allow the fasteners to engage with the electronic device. If this happens, the clip is unable to secure the heat dissipation device onto the electronic device.
What is needed, therefore, is a heat dissipation device that can overcome the limitations described.
Many aspects of the present embodiments can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present embodiments. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the views.
Specifically, the first heat-absorbing plate 20 is made of material with good heat conductivity, and has a substantially rectangular shape. The first heat-generating component 10 is attached to a bottom surface of the first heat-absorbing plate 20. Heat generated by the first heat-generating component 10 is absorbed by the first heat-absorbing plate 20 and transferred to the fin unit 30 in order to be dissipated to the ambient environment. The fastening tab 22 and the positioning tab 24 extend upwardly from two diagonally opposite corners of a top surface of the first heat-absorbing plate 20. The fastening tab 22 and the positioning tab 24 are perpendicular to each other, that is, the fastening tab 22 and the positioning tab 24 are formed from two adjacent lateral sides of the first heat-absorbing plate 20. The fastening tab 22 has a straight bottom end and a straight enlarged top end coplanar with the bottom end. The top end runs across and straddles a top extremity of the bottom end, whereby the fastening tab 22 presents as a substantially T shape to engage in the fastening hole 52 of the clip 50. The positioning tab 24 has a straight plate shape, to be capable of inserting into the positioning hole 54 of the clip 50. Understandably, the fastening tab 22 can be of other configurations in alternative embodiments, as long as the fastening tab 22 can be fixedly engaged in the fastening hole 52. The positioning tab 24 can also be altered into other shapes such as a larger top end in alternative embodiments, as long as the positioning tab 24 can be conveniently passed through the positioning hole 54.
The second heat-absorbing plate 70 has a substantially rectangular sheet configuration with a bottom surface thereof tightly attached to the second heat-generating component 11. Heat generated by the second heat-generating component 11 is absorbed by the second heat-absorbing plate 70 and transferred to the fin unit 30 to be dissipated to the ambient environment. Two fixtures 72 are engaged with two lateral sides of the second heat-absorbing plate 70. Fasteners (not shown) pass through fixing holes (not labeled) in two ends of each of the fixtures 72 to secure the second heat-absorbing plate 70 onto the printed circuit board.
The fin unit 30 comprises a plurality of vertical plate-shape fins 31 arranged side by side. A longitudinal opening is defined in each fin 31, and the openings corporately define a receiving groove 310 receiving the first and second heat pipes 40, 60.
The first heat pipe 40 comprises an evaporating section 41 connected to the first heat-absorbing plate 20 and a condensing section 42 received in the receiving groove 310 of the fin unit 30.
The clip 50 has a substantially strip-like configuration, and comprises a bulge portion 51 in the middle thereof, and two shoulders 53 extending from two ends of the bulge portion 51. The bulge portion 51 has a U-shaped configuration to span on the evaporating section 41 of the first heat pipe 40. Alternatively, the bulge portion 51 can have an arc-shaped configuration. The fastening hole 52 and the positioning hole 54 are respectively defined in the two shoulders 53, and are aligned along a longitudinal axis (not labeled) of the clip 50. Each of the fastening and positioning holes 52, 54 can be considered to have a longitudinal axis and a transverse axis. The longitudinal axis is collinear with the longitudinal axis of the clip 50, and the transverse axis is perpendicular to the longitudinal axis. Each of the fastening and positioning holes 52, 54 is generally slightly elongated along the longitudinal axis. In particular, a middle portion of each of the fastening and positioning holes 52, 54 has a substantially elliptical configuration with a long axis of the ellipse being aligned along the longitudinal axis. Each of opposite end portions of each of the fastening and positioning holes 52, 54 is narrower than the short axis of the ellipse of the middle portion, as measured parallel to the transverse axis. In the illustrated embodiment, each of the fastening and positioning holes 52, 54 is symmetrical about its longitudinal axis, and symmetrical about its transverse axis. The fastening and positioning holes 52, 54 are identical in configuration.
The fastening hole 52 is used to engagingly receive the fastening tab 24 of the first heat-absorbing plate 20, and the positioning hole 54 is used to receive the positioning tab 24 of the first heat-absorbing plate 20. Understandably, in order to permit the fastening tab 22 to insert in the fastening hole 52, transverse widths of the ends of the fastening hole 52 should be a little larger than a transverse width of the fastening tab 22. Two fixing holes (not labeled) are defined in free ends of the two shoulders 53, respectively. Fasteners can pass through the fixing holes to secure the clip 50 and the first heat-absorbing plate 20 onto the printed circuit board.
The second heat pipe 60 comprises an evaporating section 61 connected to the second heat-absorbing plate 79, a condensing section 62 received in the receiving groove 310 of the fin unit 30, and a middle section 63 interconnecting the evaporating section 61 and the condensing section 62. The second heat pipe 60 is arranged beside the first heat pipe 40. The middle section 63 spans over the first heat-absorbing plate 20 and rests on the shoulder 53 that has the positioning hole 54.
Also referring to
The condensing sections 42, 62 of the first and second heat pipes 40, 60 are both received in the groove 310 of the fin unit 30 in this embodiment. Understandably, in alternative embodiments, the condensing sections 42, 62 can further or alternatively be thermally connected to different fin units. Furthermore, in alternative embodiments, the middle section 63 of the second heat pipe 60 can be altered to rest on the shoulder 53 of the clip 50 which has the fastening hole 52.
Due to one end of the clip 50 being secured on the fastening tab 22 of the first heat-absorbing plate 20, and the other end of the clip 50 being positioned by the positioning tab 24, it is convenient and time-saving to locate the clip 50 relative to the printed circuit board and assemble the heat dissipation device to the printed circuit board. Compared with the hypothetical situation of securing the clip 50 by soldering, certain degrees of freedom of the clip 50 relative to the first heat-absorbing plate 20 are obtained. Accordingly, the position of the clip 50 can be finely adjusted to eliminate any deviations between the clip 50 and the printed circuit board which may otherwise exist due to ordinary manufacturing tolerances. Furthermore, the clip 50 is positioned and secured without the need for any soldering tools or instruments. Moreover, there is no need for surface treating (e.g. electroplating) of the clip 50 associated with a soldering operation. For at least these reasons, the heat dissipation device with the clip 50 can have a low cost and high market competitiveness.
It is believed that the present embodiments and their advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the disclosure or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments of the disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 200910311913.4 | Dec 2009 | CN | national |
