Heat dissipation assembly including heat sink and fan

A heat dissipation assembly includes a heat sink (100), a fan (200) and a fan holder (300). The heat sink includes a plurality of fins (110) and defines a groove (122) in the fins at a base end thereof. The holder includes a bracket (310). The fan is secured to a first main side of the bracket. A locating flange (352) is formed adjoining an edge of a second main side opposite to the first main side of the bracket. A pair of locking flanges (362) is formed adjoining opposite edges of the second main side of the bracket, disposed at opposite sides of the locating flange. The locating and locking flanges are received in the groove of the heat sink and abuttingly engaged with an inner defined at the heat sink in the groove. The base end of the heat sink is received between the bracket and the flanges.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a heat dissipation assembly including a heat sink and a fan, and more particularly to a heat dissipation assembly having a fan holder securely retaining the fan to the heat sink.

2. Description of Prior Art

Electronics technology continues to boom unabated. Numerous modern electronic devices such as central processing units (CPUs) of computers operate at high speed and thus generate large amounts of heat. The heat must be efficiently removed from the CPU; otherwise, abnormal operation or damage may result. Typically, a heat sink with good thermal conducting capability is mounted onto the CPU, and a fan is mounted onto the heat sink to enhance the heat dissipation capability thereof.

Most commonly, a fan is locked onto a heat sink by screws interferentially engaged with fins of the heat sink. Locking by this means is unduly laborious and slow. Additionally, the fins of the heat sink are generally thin and are liable to be deflected. Thus, the screws may loosen from the fins. The fan is liable to operate less efficiently, and may even become unserviceable.

To overcome the problems of the above-mentioned heat dissipation assembly, Taiwan Patent No. 491513 provides a heat dissipation assembly having a fan holder to mount a fan to a heat sink. The fan holder forms a plurality of catches for engaging with a periphery of the heat sink. Threaded posts are formed upwardly from the fan holder. The posts extend through holes of the fan and are engaged with corresponding nuts, thereby attaching the fan to the fan holder. However, the catches of the fan holder make it troublesome for the fan holder to be detached from the heat sink.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to provide a heat dissipation assembly including a heat sink and a fan, wherein the fan is conveniently secured to the heat sink via a fan holder.

In order to achieve the object set out above, a heat dissipation assembly in accordance with a preferred embodiment of the present invention comprises a heat sink, a fan and a fan holder. The heat sink comprises a plurality of radially distributed fins and defines a circumferential groove at a base end thereof. The heat sink defines an inner periphery in the groove. The holder comprises a bracket. The fan is secured to a first main side of the bracket. A locating flange extends away from an edge of a second main side opposite to the first main side of the bracket. A pair of locking flanges extends away from opposite edges of the second main side of the bracket. The locking flanges are disposed at opposite sides of the locating flange. The locating and locking flanges are received in the groove of the heat sink and abuttingly engaged with the inner periphery of the heat sink. The base end of the heat sink is received between the bracket and the flanges.

DETAILED DESCRIPTION OF THE INVENTION

Referring toFIG. 1, a heat dissipation assembly in accordance with the preferred embodiment of the present invention comprises a heat sink100, a fan200, and a fan holder300readily securing the fan200to the heat sink100.

The heat sink30comprises a multiplicity of radially distributed fins110. A channel120is defined between each two adjacent fins110. The fins110are integrally connected at a base end of the heat sink100. A circumferential groove122is defined in the multiplicity of fins110near the base end of the heat sink100.

The fan200comprises a rectangular frame210. The frame210comprises a pair of parallel plates212. Four locating holes214are defined through both of the plates212, at four corners of the frame210respectively.

The fan holder300comprises a bracket310defining an opening320in a middle thereof, the opening320being for communication with the channels120of the heat sink30. Four pins330extend perpendicularly from four corners of a first main side of the bracket310, corresponding to the locating holes214of the fan200. A pair of hooks340extends perpendicularly from diagonally opposite corners of said first main side of the bracket310respectively. The hooks340are adjacent an outer edge of the bracket310, and adjacent corresponding pins330respectively. A guide face342is defined at an end of each hook340, the guide face342generally facing toward an opposite lateral side of the bracket310. A stopping face344is defined on each hook340, the stopping face344being parallel to said first main side of the bracket310. A distance is defined between the stopping face344and the bracket310, corresponding to a depth of either plate212of the fan200.

A locating portion350extends perpendicularly from a second main side of the bracket310, said second main side being opposite from said first main side. The locating portion350is at a first lateral side of the bracket310. A locating flange352extends inwardly from a top of the locating portion350, the locating flange352being parallel to and spaced from the said second main side of the bracket310. An arcuate locating face354is defined at an inner side of the locating flange352, the locating face354corresponding to a periphery of the heat sink100. A locating protrusion356is formed on a middle of the locating face354, for engaging between two fins110of the heat sink100and preventing the heat sink100from rotating.

A pair of opposing locking portions360extends perpendicularly from said second main side of the bracket310. The locking portions360are at opposite second and third lateral sides of the bracket310respectively, said second and third lateral sides each being adjacent said first lateral side. A locking flange362extends from a top of each locking portion360. The locking flanges362are parallel to and spaced from said second main side of the bracket310. An arcuate locking face364is defined at an inner side of each locking flange362, the locking face364corresponding to a periphery of the heat sink100. A leading face366is defined at an end of each locking flange362that is distal from the locating portion350, the leading face366smoothly connecting with the corresponding locking face364. The leading face366and the locking face364together span an entire length of the locking flange362.

A distance between the bracket310and the locating and locking flanges352,362is determined according to the position of the groove122in the heat sink100. The locating face354and the locking faces364cooperatively define a circle having a diameter substantially the same as an inner diameter of the heat sink100in the groove122. The locating and locking flanges352,362can thereby be fittingly received in the groove122.

Referring also toFIG. 2, in assembly of the heat dissipation assembly, the fan200is placed on the fan holder300, with the locating holes214receiving the pins330of the fan holder300. The fan200is pressed onto the fan holder300. Outer walls of the fan200ride over the guide faces342of the hooks340, until a proximal one of the plates212of the fan220is snappingly received between the stopping faces344of the hooks340and the bracket310of the fan holder300. The pins330are thus fully received in the locating holes214, and prevent the fan200from moving in directions parallel to the bracket310. The hooks340sandwich the fan200against the bracket310, with the stopping faces344preventing the fan200from moving away from the fan holder300.

The base end of the heat sink100is attached on the bracket310of the fan holder300. The heat sink100is slid over the opening320toward the locating portion350, with an inner periphery of the heat sink100in the groove122riding along the leading faces366. The locking flanges362resiliently deform away from each other, and said inner periphery of the heat sink100snaps from the leading faces366to the locking faces364. Finally, the heat sink100reaches the locating portion350. The locating flange352and the locking flanges362are received in the groove122, with the locating face354and the locking faces364abutting said inner periphery of the heat sink100. The locating protrusion356is received between two fins110, and prevents the heat sink100from rotating.