Heat dissipation device

A heat dissipation device is provided for dissipating heat generated by a plurality of electronic components mounted on a printed circuit board and having different heights. The heat dissipation device includes a connecting member and a first base mounted on the connecting member and located at above one of the electronic components. A number of joining members extend through the printed circuit board and engage with the first base to assemble the first base on the one of the electronic components on the printed circuit board. A distance between the first base and the one of the electronic components is adjustable by adjusting the joining members to make the first base intimately contact with the one of the electronic components.

BACKGROUND

1. Technical Field

The present disclosure relates to heat dissipation devices and, more particularly, to a heat dissipation device thermally contacting with a plurality of electronic components having different height, to dissipate heat of the electronic components, simultaneously.

2. Description of Related Art

Generally, a heat dissipation device thermally contacts with electronic components mounted on a printed circuit board (PCB) to dissipate heat of the electronic components. The heat dissipation device comprises a base contacting with the electronic components and a plurality of fins extending upwardly from a top surface of the base. When the electronic components have different heights, the base of the heat dissipation device is not able to tightly contact with all of the electronic components at the same time; as a result, a large heat resistance will exist between the electronic components and the base, which will adversely affect the heat dissipation of the electronic components.

What is needed, therefore, is a heat dissipation device which can effectively dissipate heat generated by electronic components on a printed circuit board, wherein the electronic components have different heights.

DETAILED DESCRIPTION

FIGS. 1-2illustrate a heat dissipation device in accordance with the present disclosure. The heat dissipation device thermally contacts a first electronic component200and a second electronic component300mounted on a printed circuit board (PCB)100to dissipate heat generated by the first and second electronic components200,300at the same time. The first electronic component200is higher than the second electronic component300. The heat dissipation device comprises a connecting member10, a first heat sink20and a second heat sink30. The first and second heat sinks20,30are mounted on the connecting member10and thermally contact the first and second electronic components200,300of the PCB100, respectively.

Referring toFIGS. 3-4also, the second heat sink30comprises a second base31, a number of second pins32, a heat pipe35and a number of second fins33. The second base31thermally contacts the second electronic component300and is located at a bottom side of the connecting member10. The second pins32are secured on the second base31and extend through second through holes13of the connecting member10. The second fins33each have a T-shaped configuration and are parallel to and spaced from each other. A number of holes330are defined in each of the second fins33. The second pins32extend through the holes330of the second fins33and interferentially engage with the second fins33. Thus, the second fins33are secured on the second pins32. The heat pipe35is L-shaped and comprises an evaporating section351received in a groove310of the second base31, and a condensing section355. The heat pipe35thermally contacts the bottom side of the connecting member10on which the second fins33are located to transfer heat to the second fins33. Two screws60extend through the PCB100and engage in mounting holes313defined in two diagonally opposite ends of the second base31to mount the second heat sink30on the PCB100. The bottom surface of the second base31intimately and thermally contacts the second electronic component300.

The connecting member10is a metallic plate and has a rectangular configuration. A first end of the connecting member10defines an opening14to receive a fan (not shown). A second end opposite to the first end defines a number of first through holes12. The second through holes13are located between the opening14and the first through holes12. The first and second through holes12,13are provided for assembly of the first and second heat sinks20,30to the connecting member10. The first through holes12are arranged in matrix and located at a corner of the second end. A flange120extends upwardly from an edge of the first through hole12. The second through holes13are located near the opening14.

Referring toFIGS. 5-6also, the first heat sink20comprises a first base21, a number of first pins22secured on the first base21, a number of first fins23assembled on the first pins22and a number of elastic members40enclosing the first pins22and sandwiched between the first base21and the bottommost first fin23. Each of the first base21, the first pins22and the first fins23is made of material having good heat conductivity, such as aluminum or copper. In this embodiment, the elastic member40is a helical spring and can be compressed along an axial direction thereof.

The first base21comprises a rectangular bottom plate211contacting the first electronic component200and a top cover215secured on and covering the bottom plate211. A number of columned studs212protrude on a top surface of the bottom plate211along an edge of the bottom plate211. The studs212are integrally formed on the bottom plate211by punching. Thus, a concave213is defined in a bottom surface of the bottom plate211corresponding to each of the studs212. The top cover215is a rectangular plate and defines a number of orifices218corresponding to the studs212of the bottom plate211to receive the studs212. A diameter of each orifice218is slightly larger than that of each stud212. A number of through holes (not labeled) are defined in the top cover215. Each through hole has a circular recess216defined in a bottom of the top cover215and a circular passage217defined in a top of the top cover215. The recess216and a corresponding passage217communicate with each other and are coaxial. The recess216has a diameter larger than that of the passage217. Two sleeves219with internal thread extend integrally and downwardly from two diagonally opposite ends of the top cover215. When the top cover215and the bottom plate211are assembled together, the sleeves219extend downwardly beyond a bottom face of the bottom plate211. Two screws50extend through the PCB100and engage with the sleeves219to fix the first heat sink20on the PCB100.

Each of the first pins22is columned and comprises a head28and a body29extending upwardly from a central portion of the head28. Understandably the first pin22can be square, prism or other shape in alternative embodiments. The head28has a diameter larger than that of the body29. The first pin22has a T-shaped profile in lengthwise cross-section (shown fromFIG. 6). The head28has a height larger than a depth of the recess216. The head28is received in the recess216of the top cover215of the first base21and beyond the recess216. Preferably, the head28is 0.05-0.15 mm higher than the recess21. The body29is slightly smaller than the passage217of the top cover215. The head28is larger than the passage217.

The first fins23are parallel to and spaced from each other. A number of holes230are defined in the first fins23to allow the bodies29of the first pins22to extend therethrough. The bodies29interferantially extend through the holes230, thereby securing the first fins23on the bodies29of the first pins22.

After the second heat sink30is assembled on the PCB100, the first heat sink20is assembled on the PCB100too to thermally contact the first electronic component200of the PCB100. When the first heat sink20is assembled, the bodies29of the first pins22extend through the passages217of the top cover215from bottom to top, and top portions of the heads28are received in the recesses216of the top cover215. The bottom plate211is pressed upwardly toward the top cover215whereby the bottom plate211contacts bottom ends of the heads28. Each of the heads28is pressed to deform and expand to fill a gap between the head28and the recess216. In this state, a bottom surface of the head28is coplanar to the bottom surface of the top cover215. Thus, the bottom plate211intimately contacts the bottom surface of the top cover215and the heads28of the first pins22. Simultaneously, the studs212of the bottom plate211are received in the orifices218of the top cover215. The studs212are punched to deform and thereby rivet into the orifices218and intimately joint the bottom plate211and top cover215together. In this state, the first base21and the first pins22are assembled together. The bodies29of the first pins22extend through the first holes12of the connecting member10from bottom to top. The elastic members40are positioned around peripheries of the flanges120of the connecting member10and abut against a top surface of the connecting member10. The bodies29extend through the holes230of the first fins23and are interferentially engaged with the first fins23. The elastic members40abut against the bottommost first fin23. The bottom plate211of the first heat sink20is arranged on the first electronic component200. Two screws50extend through the PCB100and engage with the sleeves219of the bottom plate211to fix the first heat sink20on the PCB100. A distance between the bottom plate211and the first electronic component200is adjustable by tightening the screws50. The elastic members40are compressed by the first base21and the bottommost fin23. Thus, a force afforded by the elastic members40pushes the first base21and the connecting member10toward the first electronic component200to make the first base21intimately connect with the first electronic component200.