Air cooled computer chip

TECHNICAL FIELD

0001The subject invention relates to a cooling assembly for cooling an electronic component with direct air.

BACKGROUND OF THE INVENTION

0002The operating speed of computers is constantly being improved to create faster computers. With this, comes increased heat generation and a need to effectively dissipate that heat.

0003Heat exchangers and heat sink assemblies have been used that apply natural or forced convection cooling methods to dissipate heat from electronic devices that are highly concentrated heat sources such as microprocessors and computer chips. The most common method of cooling computer chips has been direct air cooling, which is adequate for the moderate thermal load generated by the chip. These heat exchangers typically use air to directly remove heat from the electronic devices; however air has a relatively low heat capacity. Thus, liquid-cooled units called LCUs employing a cold plate in conjunction with high heat capacity fluids have been used to remove heat from these types of heat sources. Although LCUs are satisfactory for moderate heat flux, increasing computing speeds have required more effective heat sink assemblies.

0004Accordingly, thermosiphon cooling units (TCUs) have been used for cooling electronic devices having a high heat flux. A typical TCU absorbs heat generated by the electronic device by vaporizing the working fluid housed on the boiler plate of the unit. The boiling of the working fluid constitutes a phase change from liquid-to-vapor state and as such the working fluid of the TCU is considered to be a two-phase fluid. The vapor generated during boiling of the working fluid is then transferred to a condenser, where it is liquefied by the process of film condensation over the condensing surface of the TCU. The heat is rejected into a stream of air flowing through a tube running through the condenser or flowing over fins extending from the condenser. Alternatively, a second refrigerant can flow through the tube increasing the cooling efficiency. The condensed liquid is returned back to the boiler plate by gravity to continue the boiling-condensing cycle.

0005In recent years the generation of higher thermal load is being handled by improving the chip design such that even with higher computing speeds the chip does not generate large amounts of heat. Thus, chip cooling can be handled by air cooling without having to resort to LCUs or TCUs. Although the prior art dissipates heat from electronic devices, as computing speeds increase, there is a continuing need for cooling assemblies having more efficient or alternative heat transfer capabilities as compared to the conventional electronic cooling assemblies.

SUMMARY OF THE INVENTION

0006The invention provides a cooling assembly for cooling an electronic component with direct air. The assembly includes a housing and at least one electronic component disposed in the housing. A nozzle is supported in the housing and directs cooling air over the electronic component. An open air cycle cooling unit is disposed in the housing and supplies the cooling air to the nozzle. The cooling unit includes a casing and a compressor rotatably supported by the casing for moving air. The assembly is distinguished by having air bearings that support the compressor in the casing on a thin film of air, thereby maintaining a contaminate free housing.

0007Accordingly, the subject invention provides an enhanced air cooling assembly. The open air cycle cooling unit is housed inside the computer case or housing, and enhances the cooling efficiency. With no oil introduced into the air stream, the open air cycle cooling unit is ideal for cooling electronic components.

BRIEF DESCRIPTION OF THE DRAWINGS

0008Other advantages of the present invention will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

0009Figure 1 is a perspective view of the subject invention;

0010Figure 2 is an schematic view of air being directed over an electronic chip in the subject invention;

0011Figure 3 is a perspective view of a casing utilized for the air cycle cooling unit in the subject invention;

0012Figure 4 is a side view of a thrust bearing utilized in the subject invention;

0013Figure 5 is an exploded view of a thrust bearing utilized in the subject invention;

0014Figure 6 is an exploded view of a journal bearing utilized in the subject invention;

0015Figure 7 is a fragmentary end view partially broken away and in cross section of the journal bearing shown in Figure 6; and

0016Figure 8 is a schematic of the air cycle cooling unit utilized in the subject invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

0017Referring to the Figures, wherein like numerals indicate corresponding parts throughout the several views, a cooling assembly <b>20</b> is generally shown for cooling an electronic component with direct air in Figures 1-4.

0018The subject invention comprises a housing <b>22</b> generally indicated which has a generally rectangular periphery that defines four corners <b>24, 26</b> (only the first and second of the four corners are numbered). The housing <b>22</b> is typically made of metal, but may be any other material known in the art. The housing <b>22</b> includes a housing bottom <b>28</b> and a housing top <b>30</b> with spaced and parallel side walls <b>32, 34.</b> The side walls <b>32, 34</b> are solid and extend between the housing bottom <b>28</b> and the housing top <b>30.</b> The housing <b>22</b> further includes opposite housing ends <b>36</b> and a longitudinal housing axis <b>38.</b> The housing bottom <b>28,</b> the side walls <b>32, 34,</b> and the housing top <b>30</b> extend axially between the housing ends <b>36</b> to define an air entrance <b>40</b> at one of the housing ends <b>36</b> and an air exit <b>42</b> at the other of the housing ends <b>36.</b> The air entrance <b>40</b> and air exit <b>42</b> allow for the flow of air through the housing <b>22.</b>

0019An entrance plate <b>44</b> is disposed at the air entrance <b>40.</b> The entrance plate <b>44</b> has a plurality of entrance apertures <b>46</b> for the flow of air through the air entrance <b>40.</b> The air entrance <b>40</b> is typically made of metal, but may be any other material known in the art.

0020An exit plate <b>48</b> is disposed at the air exit <b>42.</b> The exit plate <b>48</b> has a plurality of exit apertures <b>50</b> for the flow of air through the air exit <b>42.</b> The air exit <b>42</b> is typically made of metal, but may be any other material known in the art.

0021A first electronics box <b>52</b> is disposed at a first corner <b>24</b> adjacent a first side wall <b>32</b> and the air entrance <b>40</b> for providing electric signals to the assembly <b>20.</b> A second electronics box <b>54</b> is disposed at a second corner <b>26</b> adjacent the first side wall <b>32</b> and the air exit <b>42</b> for providing electric signals to the assembly <b>20.</b>

0022The assembly <b>20</b> further includes a plurality of electronic components disposed within the housing <b>22.</b> The electronic components including a mother board <b>56</b> disposed on the housing bottom <b>28,</b> a plurality of circuits <b>58</b> disposed on the mother board <b>56,</b> and a plurality of electronic chips <b>60</b> disposed on the mother board <b>56.</b> A plurality of cold plates <b>62</b> having a plurality of heat transfer fins <b>64</b> are disposed on the chips <b>60.</b>

0023The assembly <b>20</b> further includes an open air cycle cooling unit <b>66</b> generally indicated that is disposed in the housing <b>22</b> for cooling the air that cools the electronic components. The cooling unit <b>66</b> includes a plurality of fans <b>68</b> that are disposed side-by-side between the second electronics box <b>54</b> and a second side wall <b>34.</b> The fans <b>68</b> are parallel to the exit plate <b>48</b> and move air through the exit apertures <b>50</b> in the exit plate <b>48.</b>

0024The cooling unit <b>66</b> includes a heat exchanger <b>70</b> for cooling air. The heat exchanger <b>70</b> is disposed between and parallel to the plurality of fans <b>68</b> and the exit plate <b>48.</b> The heat exchanger <b>70</b> includes a heat exchanger inlet <b>72</b> and a heat exchanger outlet <b>74</b> for the flow of hot compressed air through the heat exchanger <b>70.</b> The cooling unit <b>66</b> further includes a casing <b>76</b> generally indicated having opposite casing ends <b>78</b> and a casing axis <b>80</b> extending parallel to the housing axis <b>38.</b> The casing <b>76</b> is supported on the housing bottom <b>28</b> between the plurality of fans <b>68</b> and the air entrance <b>40.</b> A shaft <b>82</b> is rotatably supported along the casing axis <b>80</b> between the casing ends <b>78.</b>

0025A compressor <b>84</b> is mounted on the shaft <b>82</b> at the one of the casing ends <b>78</b> nearer the air entrance <b>40.</b> The compressor <b>84</b> has a compressor inlet <b>86</b> and a compressor outlet <b>88</b> for establishing the flow of air through the heat exchanger <b>70.</b> An expander <b>90</b> is mounted on the shaft <b>82</b> at the one of the casing ends <b>78</b> nearer the air exit <b>42.</b> The expander <b>90</b> reduces the pressure of air that flows through the expander <b>90</b> and rotates the shaft <b>82.</b> The expander <b>90</b> has an expander inlet <b>92</b> and an expander outlet <b>94</b> for the flow of air through the expander <b>90.</b> An electric motor <b>96</b> rotates the shaft <b>82</b> and is disposed in the casing <b>76</b> between the compressor <b>84</b> and the expander <b>90.</b>

0026The cooling unit <b>66</b> further includes a nozzle <b>98</b> that distributes air over the cold plates <b>62.</b> The nozzle <b>98</b> includes a nozzle inlet <b>100</b> and a plurality of nozzle outlets <b>102</b> disposed over the cold plates <b>62.</b>

0027A first air tube <b>104</b> interconnects the compressor outlet <b>88</b> to the heat exchanger inlet <b>72</b> for the flow of air therebetween. A second air tube <b>106</b> interconnects the heat exchanger outlet <b>74</b> to the expander inlet <b>92</b> for the flow of air therebetween. A third air tube <b>108</b> interconnects the expander outlet <b>94</b> to the nozzle inlet <b>100</b> for the flow of air therebetween.

0028The subject invention is distinguished by air bearings <b>110, 112</b> that support the shaft <b>82</b> on a thin film of air and thus maintain a contaminate free air stream. The air bearings <b>110, 112</b> are self-actuated hydrodynamic air bearings <b>110, 112</b> and require no source of compressed air. The air bearings <b>110, 112</b> include a plurality of journal bearings <b>110</b> that support the radial load of the shaft <b>82</b> and a plurality of thrust bearings <b>112</b> that support the axial load of the shaft <b>82.</b>

0029As air enters the compressor inlet <b>86</b> air is compressed. The volume of the compressed air is reduced and the temperature increases. The hot compressed air exits the compressor outlet <b>88</b> into the first air tube <b>104</b> where it flows to the heat exchanger inlet <b>72.</b> The hot compressed air flows through the heat exchanger <b>70</b> where it is cooled by the fans <b>68.</b> The fans <b>68</b> move air through a plurality of spaced fins on the heat exchanger <b>70.</b> The cooled air exits the heat exchanger <b>70</b> through the heat exchanger outlet <b>74</b> into the second air tube <b>106</b> where it flows to the expander inlet <b>92.</b> The volume of the cooled air is expanded and the temperature of the cooled air is further reduced. The cooled air exits the expander outlet <b>94</b> into the third air tube <b>108</b> where it moves to the nozzle inlet <b>100.</b> The cooled air is distributed over the electronic component by the nozzle outlet <b>102</b> that is placed over the electronic component to be cooled.

0030The subject invention may include a water separator, which is generally located at the heat exchanger outlet <b>74.</b> The need of a water separator can be eliminated by controlling the temperature of the air coming out of the expander <b>90</b> just above the dew point temperature of the air entering the compressor <b>84.</b> The temperature can be controlled through the use of a controls system that monitors the temperature of the air exiting the expander <b>90.</b>

0031While the invention has been described with reference to an exemplary embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.