Heat sink assembly having a fin also functioning as a supporting bracket

A heat sink assembly (100) for cooling a heat-generating electronic component, includes a base plate (32), a plurality of fins (50) mounted on the base plate and a heat pipe (20) thermally connecting the base plate and the fins. The fins are parallel to the base plate and include a bottom fin (40) supporting the fins on the base plate. The bottom fin includes a plurality of supporting tabs (422) engaging with the base plate and separating a body (42) of the bottom fin from the base plate. The bottom fin can be used not only for dissipating heat into a surrounding environment but also for reinforcing the whole strength of the heat sink assembly.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a heat sink assembly having a plurality of fins, wherein at least one fin functions as a supporting bracket to reinforce the whole strength of the heat sink assembly.

2. Description of related art

Nowadays, numerous heat sinks are used to dissipate heat generated by electronic devices. A tower type heat sink is a common structure of the heat sinks. The tower type heat sink generally comprises a base, a plurality of fins parallel to the base and a heat pipe thermally connecting the base and the fins. The heat sink has a relatively high height. Thus, the heat sink is prone to becoming deformed when subjected to shock or vibration during transportation or use.

Thus, it is desired to devise a heat sink which has a strengthened structure to improve deformation-resistance thereof.

SUMMARY OF THE INVENTION

According to a preferred embodiment of the present invention, a heat sink assembly for cooling a heat-generating electronic component includes a base plate, a plurality of fins mounted on the base plate and a heat pipe thermally connecting the base plate and the fins. The fins are parallel to the base plate and include a bottom fin supporting the fins on the base plate. The bottom fin includes a plurality of supporting tabs extending downwards therefrom to engage with the base plate. The bottom fin functions not only for dissipating heat into a surrounding environment but also for reinforcing the whole strength of the heat sink assembly.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1-2show a heat sink assembly100in accordance with a preferred embodiment of the present invention. The heat sink assembly100is to be mounted on a printed circuit board (not shown) for dissipating heat generated by an electronic device (not shown) attached on the printed circuit board.

The heat sink assembly100comprises a heat spreader10adapted for contacting with the electronic device, a pair of heat pipes20, a seat30, a supporting bracket40and a fin assembly50. The heat pipes20thermally connect the heat spreader10, the seat30, the supporting bracket40and the fin assembly50.

The heat spreader10has a bottom face (not labeled) for contacting the electronic device mounted on the printed circuit board to absorb heat therefrom, and a top face12with a pair of parallel and adjoining grooves120.

Each heat pipe20comprises a horizontal evaporating portion22and a vertical condensing portion24arranged in such a manner that the heat pipe20has an L-shaped configuration. The condensing portion24extends perpendicularly from one of free ends of the evaporating portion22. The evaporating portions22of the heat pipes20are soldered in the grooves120of the heat spreader10. The condensing portions24are located at opposite lateral sides of the heat spreader10, and extend through the seat30, the supporting bracket40and the fin assembly50.

Also referring toFIGS. 3-4, the seat30comprises a base plate32, a connecting element31and a protecting element33attached to the base plate32. A temperature sensor60(shown inFIG. 2) is mounted between the connecting element31and the protecting element33, for controlling a speed of a fan (not shown) mounted on the heat sink assembly100. The base plate32has a rectangular configuration and is made of metallic material, such as aluminum. Four poles320extend downwardly from four corners of the base plate32, for providing passage for corresponding fasteners70to mount the seat30on the printed circuit board. A rectangular through slot321is defined in a central portion of the base plate32for receiving the connecting element31therein. A pair of openings322are defined at both flanks of the slot321for receiving the evaporating portions22and curved portions (not labeled) of the heat pipes20. Two beams323,324are formed between the slot321and the openings322. The beam324defines a V-shaped slot3242at a top thereof for providing passage for a signal wire of the sensor60. Each of the beams323,324defines a pair of adjoining semicircular grooves3230,3240at a bottom thereof. The heat spreader10is mounted on a bottom of the two beams323,324. The semicircular grooves120of the heat spreader10are in vertical alignment with the semicircular grooves3230,3240of the beams323,324. Four bars325are formed on the bottom of the base plate32, for preventing movement of the heat spreader10relative to the base plate32of the seat30.

The connecting element31is received in the slot321of the base plate32. The connecting element31defines a pair of semicircular grooves310horizontally in alignment with the grooves3230,3240of the base plate32. These grooves310,3230,3240and the grooves120of the heat spreader10cooperatively define a pair of channels (not labeled) for receiving the evaporating portions22of the heat pipes20therein. The connecting element31defines a V-shaped slot312at a top portion thereof horizontally in alignment with the slot3242of the beam324of the base plate32.

The protecting element33is mounted on the base plate32and engages with the connecting element31. The protecting element33has a rectangular configuration and defines a rectangular receiving space330defined by four sidewalls332of the protecting element33. The receiving space330and the V-shaped slot312of the connecting element31cooperatively receiving the sensor60therein. A cutout334is defined at a bottom edge of one of the sidewalls322of the protecting element33for facilitating passage of the signal wire of the sensor60.

Referring toFIG. 2again, the fin assembly50comprises a plurality of fins each having a flat body52parallel to the base plate32. The bodies52of the fins are perforated with through holes520. Each of the through holes520has its respective annular sidewall522that is formed during punching. The condensing portions24of the heat pipes20are received in the through holes520and soldered to the sidewalls522so that the fin assembly50are combined with the condensing portions24of the heat pipes20. The fin assembly50has a bottom fin functioning as the supporting bracket40. The supporting bracket40supports the fin assembly50on the base plate32of the seat30and reinforces the whole strength of the fin assembly50, in addition to its original function of heat dissipation.

The supporting bracket40also has a body42with a configuration similar to that of each of the bodies52of the fins. A pair of opposite sidewalls420extend perpendicularly and downwardly from front and rear edges of the body42. A pair of connecting walls421are bent inwards and horizontally from edges of the sidewalls420. A pair of L-shaped supporting tabs422respectively extend downwardly and vertically from an edge of each connecting wall421. The two pairs of supporting tabs422are located at opposite ends of the body42. A flat engaging portion4220is formed horizontally and inwardly at a free end of each supporting tab422for engaging with a top surface of the base plate32.

In assembly of the preferred embodiment of the present invention, the evaporating portions22of the heat pipes20are received in the bottom of the base plate32after the connecting element31is mounted on the base plate32of the seat30. The heat spreader10is attached on the bottom of the base plate32and engages with the evaporating portions22of the heat pipes20. The protecting element33covers the connecting element31after the sensor60is received in the connecting element31. The supporting bracket40and the fin assembly50are mounted on the base plate32of the seat30in series. The condensing portions24are extended through the supporting bracket40and the fin assembly50simultaneously. Thus, the heat sink assembly100is assembled together.

Referring toFIGS. 5-6, a heat sink assembly100aaccording to a second embodiment of the present invention is shown. The heat sink assembly100ain the second embodiment comprises a base plate10a, a heat pipe20a, a fixing block60a, a supporting bracket40aand a fin assembly50a. The heat pipe20athermally connects the base plate10a, the fixing block60a, the supporting bracket40aand the fin assembly50a.

The base plate10ahas a square body11a. Four ears12aextend horizontally from a center of each sidewall of the body11a. Four corresponding fasteners70aextend through the four ears12afor mounting the heat sink assembly100aonto a printed circuit board (not shown). An arced slot110aand a rectangular slot112aare defined crossing in the body11a. The slots110a,112aare both defined at a central portion of the body11a. The slot110ais deeper than the slot112a.

The heat pipe20acomprises an arced evaporating portion22aand a pair of vertical condensing portions24aperpendicularly extending from two opposite ends of the evaporating portion22a. The evaporating portion22aof the heat pipe20ais received in the slot110aof the base plate10a. The fixing block60ais received in the slot112aof the base plate10a. A pair of rivets62aextend through the fixing block60aand engage in the base plate10ato mount the fixing block60aonto the evaporating portion22aof the heat pipe20a.

The fin assembly50acomprises a plurality of fins each having a flat body52aparallel to the base plate10a. Each flat body52ais perforated with a pair of through holes520a. The condensing portions24aof the heat pipe20aare soldered in the through holes520aso that the fins are joined with the heat pipes20a. The fin assembly50ahas a bottom fin functioning as the supporting bracket40ato support the fin assembly50on the base plate10aand reinforce the strength of the fin assembly50a. The supporting bracket40ahas a portion corresponding to and vertically in alignment with each body52aof the fin assembly50a, and another portion extending beyond the body52a. The supporting bracket40ahas a top surface42aparallel to each body52aof the fin assembly50a. A pair of spaced through holes420aare defined at the top surface42aof the supporting bracket40aand vertically in alignment with the through holes520of the fin assembly50a. The top surface42aof the supporting bracket40ais stamped downwardly to form a pair of U-shaped supporting tabs422alocated below the top surface42a. The supporting tabs422atraverse between the two condensing portions24aof the heat pipes20a. Each U-shaped supporting tabs422adefines a corresponding U-shaped recess44a. Each of the supporting tabs422acomprises a flat engaging portion4220aengaging with a top surface of the base plate10a.

In the present invention, by the provision of the supporting brackets40,40aformed by the bottom fin of the fin assembly50,50a, the fin assembly50,50acan be firmly mounted to the base plate30/base plate10a. Thus, strength of the heat sink assembly is increased.