Patent Application
20080066898
Many aspects of the present apparatus and method 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 apparatus and method. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
Referring to
Referring also to
The first fin unit 13 is formed by aluminum extrusion and comprises a cylindrical collar 131 and a plurality of helical first fins 133 extending radially and outwardly from a circumferential face of the collar 131. A first receiving hole 1311 is defined through the first fin unit 13 and is surrounded by the collar 131, for interferentially accommodating the column 113 of the core 11 therein. Each of the first fins 133 anticlockwise curves along a circumferential direction of the collar 131. Each of the first fins 133 comprises a trunk 1331 and a pair of tines 1333 divided from the trunk 1331 at an outer portion of the respective first fin 133. The dividing of each first fin 133 into the tines 1333 occurs at a bifurcate point that may, for example, be about halfway along the length of the first fins 133. Each trunk 1331 has a root (not labeled) emerging in an outward direction from the collar 131, and each tine 1333 has a root (not labeled) emerging in an outward direction from the bifurcate point thereof. Each tine 1333 also has a tip at an end of the tin 1333 opposite the tine root. For each first fin 133, it can be considered as having two tips formed by the tines. The length of the first fin 133 is defined by the curvilinear distance along the first fin 133 from the root of the trunk 1331 to either of the tips of the two tines 1333 of the first fin 133. Each first fin 133 has a convex surface (not labeled) extending from the root of the trunk 1331 to the tip of one of the tines 1333 of the first fin 133. Each first fin 133 also has a concave surface (not labeled) opposite to the convex surface and extending from the root of the trunk 1331 to the tip of the other one of the tines 1333 of the first fin 133. A plurality of first passages (not labeled) is defined between the adjacent trunks 1331 and the adjacent tines 1333 of the first fins 133 for airflow flowing therethrough.
The second fin unit 15 is similar to the first fin unit 13, and comprises a plurality of second fins 153; however, each of the second fins 153 clockwise curves along a circumferential direction of a collar 151 thereof. A second receiving hole 1511 is defined through a center of the second fin unit 15 for accommodating the column 113 of the core 11 therein. Each of the second fins 153 comprises a trunk 1531 and a pair of tines 1533 splits from the trunk 1531 at about halfway along the length thereof. A plurality of second passages (not labeled) is defined between the adjacent trunks 1531 and the adjacent tines 1533 of the second fins 153.
The locking device 30 comprises a substantially rectangular locking plate 31 and four locking legs 33 extending from four corners of the plate 31, respectively. An opening 311 is defined in a center of the plate 31 for the column 113 of the core 11 to extend therethrough. A diameter of the opening 311 is smaller than that of the heat receiver 111 but substantially equal to that of the column 113 of the core 11. Each of the legs 33 defines a screw aperture 331 therein for accommodating a fastener (not shown) therein to fasten the heat dissipation device to the printed circuit board so that a bottom face of the heat receiver 111 can have an intimate contact with the electronic device. A sleeve 333 depends from each of the legs 33 under the screw aperture 331. The sleeves 333 are used for guiding the movement of the fasteners.
Referring also to
Referring to
In use, the heat dissipation device is attached to the electronic device with the heat receiver 111 of the heat sink thermally contacting the electronic device. The heat generated by the electronic device is absorbed by the heat receiver 111, and then is transferred to the first and second fin units 13, 15 via the column 113 of the core 11. The fan 60 provides forced airflow to the second and first fin units 15, 13. The airflow from the fan 60 passes through the second and first passages of the second and first fin units 15, 13 and removes the heat in the second fins 153 and the first fins 133 to ambient air. According to this preferred embodiment, the fan 60 is operated to rotate anticlockwise.
Table 1 below shows temperature data obtained from laboratory tests of the heat dissipation device of the related art and the heat dissipation device of the present invention. The tests were conducted with the environment temperature being Ta. Tc represents the temperature that the heat generating electronic device operates with the related heat dissipation device or the heat dissipation device of the present invention. The table shows that heat resistance θ of the heat dissipation device of the present invention is always lower than heat resistance θ of the related heat dissipation device under the same condition. That is to say, heat dissipation efficiency of the instant heat dissipation device of the present invention is higher than that of the related heat dissipation device. In the table, letter A denotes the related heat dissipation device, while letter B denotes the heat dissipation device of the present invention. Letter M denotes the first fin unit 13 of the heat dissipation device of the present invention; letter N denotes the second fin unit 15 of the heat dissipation device of the present invention.
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 invention or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments of the invention.
