Patent Application
20050007735
This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2003-147804, filed May 26, 2003.
1. Field of the Invention
The present invention relates to a liquid-cooling electronic apparatus that cools a heat-generating component, such as a semiconductor package and a chip set, with liquid coolant, and a structure adapted to separate air bubbles from liquid coolant circulating in a circulating path.
2. Description of the Related Art
Microprocessors for use in notebook-type portable computers generate more heat while operating, as they process data at higher speeds and perform more functions. Recently, so-called liquid-cooled cooling systems have been developed to cool the microprocessors.
U.S. Pat. No. 6,519,147 discloses a liquid-cooling system used in a notebook size portable computer including a body portion and a display portion. The cooling system is provided with a heat-receiving portion thermally connected to a heat-generating component, such as a CPU and a chip set, and a path filled with cooling liquid. The path is connected to the heat-receiving portion and is provided between the body portion and the display portion. The display portion accommodates a reserve-tank that reserves the cooling liquid. The reserve-tank supplies to the path with the cooling liquid, and is connected to the path through a check valve for backflow prevention.
U.S. Pat. No. 5,871,526 discloses a liquid-cooling system provided with a reserve-tank that supply to a liquid-circulating path with liquid, and the use of the reserve-tank as an air-liquid separator.
The separator disclosed in U.S. Pat. No. 5,871,526 includes a vessel containing liquid, a first path used to return the liquid circulating in the path to the vessel, and a second path used to lead the liquid out from the vessel. Each of the first and second paths includes an outlet and an inlet that open inside the vessel. The outlet of the first path opens to an air layer in the upper portion of the vessel, while the inlet of the second path opens in the vicinity of the bottom of the vessel.
In the notebook size portable computer disclosed in U.S. Pat. No. 6,519,147, the display portion with the reserve-tank is allowed to rotate between a closed position and an opened position. Incidentally, because the portable computer is placed in a bag or the like and carried along frequently, the posture of the portable computer is changed in various manners depending on the mode of usage. For this reason, the liquid level inside the reserve-tank is changed depending on the mode of usage. It is thus well anticipated that when the structure of the air-liquid separator disclosed in U.S. Pat. No. 5,871,526 is adapted to the reserve-tank disclosed in U.S. Pat. No. 6,519,147, turnover of the vessel may occur when the portable computer is in a given posture. This result in a problem that the inlet of the second path positioned in the bottom of the vessel comes above the liquid level, allowing air inside the vessel to be taken into the second path.
In the liquid-cooling system, once the cooling liquid gets mixed with air bubbles as a change in posture of the portable computer occurs, the performance of receiving the heat from the CPU in the heat-receiving portion is deteriorated.
Embodiments of the present invention is to provide an liquid-cooling system capable of a heat-generating component preventing liquid coolant from getting mixed with air bubbles even when the posture of the reserve-tank is changed.
According to one aspect of the invention, there is provided a liquid cooled electronic apparatus having a reserve tank. *******The reserve-tank is provided on the circulating path for storing a portion of the liquid coolant. The circulating path includes a first path for providing fluid communication of the liquid coolant to the reserve tank; and a second for providing fluid communication of the liquid coolant from the reserve tank. The second path has an inflow portion for intake of the liquid coolant from within the reserve-tank. The inflow portion is positioned at or near a center portion of the inside of the reserve-tank.
The liquid level within said reserve tank does not completely filing said reserve tank and leaves an air portion therein. The liquid level within said reserve tank and the position of said inflow portion are such that the inflow portion is constantly submerged below a liquid level of the liquid coolant for any orientation or attitude of the apparatus. In this manner, air bubbles will not enter the circulation path of the liquid coolant.
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention.
Embodiments of the present invention will be described, with reference to the accompanying drawings.
FIGS. 1 to 7 show a portable computer 1 as an electronic apparatus. The portable computer 1 is provided with a body 2 and a display unit 3. The body 2 includes a first housing 4 of a flat box-shape. The first housing 4 supports a keyboard 5 and the front half of the upper surface thereof defines a palm rest 6.
A mounting portion 7 is formed at the rear end portion of the first housing 4. The mounting portion 7 extends in the width direction of the first housing 4 while protruding upward above the upper surface of the first housing 4 and the keyboard 5. The mounting portion 7 includes first through third convex hollow portions 8a, 8b, and 8c. The first convex hollow portion 8a protrudes upward from one end of the mounting portion 7. The second convex hollow portion 8b protrudes upward from the other end of the mounting portion 7. The third convex hollow portion 8c protrudes upward from the center of the mounting portion 7 and is positioned between the first convex hollow portion 8a and the second convex hollow portion 8b.
As shown in
The display unit 3 is a single independent component separated from the body 2. The display unit 3 is provided with a liquid crystal display panel 14 used as a display apparatus, and a second housing 15 that accommodates the liquid crystal display panel 14. The liquid crystal display panel 14 includes a screen 14a on which an image is displayed. The second housing 15 is of a flat box-shape, and a square opening portion 16 is made in the front. The screen 14a of the liquid crystal display panel 14 is exposed to the outside of the second housing 15 through the opening portion 16.
The second housing 15 includes a back plate 17 positioned behind the liquid crystal display panel 14. A pair of convex hollow portions 17a and 17b as shown in
As shown in
First through third concave portions 22a, 22b, and 22c are formed in the third housing 21 at one end portion. The first and second concave portions 22a and 22b are spaced apart from each other in the width direction of the third housing 21 so as to correspond to the first and second convex hollow portions 8a and 8b of the mounting portion 7, respectively. The first and second convex hollow portions 8a and 8b fit inside the first and second concave portions 22a and 22b, respectively. The third concave portion 22c is positioned between the first and second concave portions 22a and 22b so as to correspond to the third convex hollow portion 8c of the mounting portion 7. The third convex hollow portion 8c fits inside the third concave portion 22c.
The third housing 21 is coupled to the mounting portion 7 of the first housing 4 at one end portion through a pair of hinges 23a and 23b. One hinge 23a lies astride the first convex hollow portion 8a of the mounting portion 7 and the third housing 21. The other hinge 23b lies astride the second convex hollow portion 8b of the mounting portion 7 and the third housing 21. Each of the hinges 23a and 23b has a horizontal, rotational axis line X1 (
A pair of concave portions 25a and 25b are formed at the other end portion of the third housing 21. The concave portions 25a and 25b are spaced apart from each other in the width direction of the third housing 21 to correspond to the convex hollow portions 17a and 17b of the second housing 15, respectively. The convex hollow portions 17a and 17b fit inside the concave portions 25a and 25b, respectively.
The third housing 21 is coupled to the back plate 17 of the second housing 15 at the other end portion through another pair of hinges 26a and 26b. One hinge 26a lies astride one convex hollow portion 17a of the second housing 15 and the third housing 21. The other hinge 26b lies astride the other convex hollow portion 17b of the second housing 15 and the third housing 21. Each of the hinges 26a and 26b has a horizontal, rotational axis line X2 extending in the width direction of the second housing 15. The rotational axis lines X2 of the hinges 26a and 26b are coaxial. The other end portion of the third housing 21 is therefore coupled to the back plate 17 of the second housing 15 rotatably about the rotational axis lines X2.
In other words, the third housing 21 is allowed to rotate between a position at which the third housing 21 overlaps the back plate 17 of the second housing 15 and a position at which the third housing 21 stays apart from the back plate 17. In addition, the third housing 21 is maintained at the respective positions by braking forces exerted by the hinges 26a and 26b.
Accordingly, the display unit 3 is coupled rotatably to the body 2 through the supporting member 20, while being allowed to rotate by itself independently from the supporting member 20. To be more specific, the display unit 3, overlapping the supporting member 20, is allowed to rotate between a first position and a second position.
By rotating the display unit 3 upward while the display unit 3 is rotated to and maintained at the intermediate point between the first position and the second position, the back plate 17 of the second housing 15 moves away from the supporting member 20. This in turn, as shown in
As shown in
The pump 31 also serves as a heat-receiving portion that receives heat generated in the CPU 11. The pump 31 is accommodated in the first housing 4, and is installed on the upper surface of the printed circuit board 10. As shown in
The pump housing 35 is of a flat box-shape larger than the CPU 11, and is made of a material having excellent heat conductance, for example, aluminum alloy. The pump housing 35 includes a bottom wall 37a, a top wall 37b, and four sidewalls 37c. The walls 37a, 37b, and 37c together define a pump chamber 38 inside the pump housing 35. The impeller 34 is accommodated in the pump chamber 38.
Further, the pump housing 35 includes an intake port 39 (
The lower surface of the bottom wall 37a of the pump housing 35 defines a flat heat-receiving surface 42. The heat-receiving surface 42 is of a size large enough to cover the CPU 11 from above. The pump housing 35 includes four foot portions 43. The foot portions 43 are positioned at the four corners of the pump housing 35, respectively, and each protrudes below the heat-receiving surface 42. Each foot portion 43 is fixed to the upper surface of the printed circuit board 10 through a screw 44. This fixation allows the pump housing 35 to overlap the CPU 11 and the IC chip 13 of the CPU 11 to be thermally connected to the center of the heat-receiving surface 42.
The heat-radiating portion 32 of the cooling apparatus 30 is accommodated in the third housing 21 of the supporting member 20. As shown in
The fan 50 includes a fan case 53, and a centrifugal impeller 54 accommodated in the fan case 53. The fan case 53 is made of a material having excellent heat conductance, for example, aluminum alloy. The fan case 53 comprises a square case body 55 and a cover 56. The case body 55 includes a sidewall 58 that stands on the edge on one side, and a pair of boss portions 59a and 59b positioned at the edge on the side opposite to the sidewall 58. The cover 56 is fixed to lie astride the tip end of the sidewall 58 and the tip ends of the boss portions 59a and 59b.
The impeller 54 is supported by the case body 55, and is disposed between the case body 55 and the cover 56. The impeller 54 is driven by an unillustrated flat motor, for example, when the power is supplied to the portable computer 1 or the temperature of the CPU 11 reaches a predetermined value.
The fan case 53 includes a pair of intake ports 61a and 61b, and first through third discharge ports 62a, 62b, and 62c. The intake ports 61a and 61b are made in the cover 56 and the case body 55, respectively, and thereby oppose each other with the impeller 54 in between.
As shown in
Consequently, the first through third discharge ports 62a, 62b, and 62c are placed to maintain a positional relation so that they surround the outer periphery of the impeller 54 in three directions. In other words, the first through third discharge ports 62a, 62b, and 62c of the fan case 53 open in three directions with respect to the rotational center O1 of the impeller 54. Thus, compared with the conventional arrangement in which the discharge port opens only in one direction, a wider range of opening with respect to the rotational center O1 of the impeller 54 is secured by the first through third discharge ports 62a, 62b, and 62c.
In the fan 50 arranged as above, when the impeller 54 starts to rotate, as indicated by arrows of
Hence, in the case of the fan 50 of this embodiment, by forming the first through third discharge ports 62a, 62b, and 62c that open to the fan case 53 in three directions, it is also possible to increase a volume of cooling air while maintaining a pressure of the cooling air discharged through the discharge ports 62a, 62b, and 62c thus formed. The inventor of the invention conducted an experiment, and it was confirmed that both a volume and a pressure of cooling air discharged through the discharge ports 62a, 62b, and 62c were satisfactory by giving 190? or greater to the range of opening of the first through third discharge ports 62a, 62b, and 62c with respect to the rotational center O1 of the impeller 54.
The fan case 53 of the fan 50 is fixed to the inner surface of the bottom plate 21b of the third housing 21 through screws. The top plate 21a and the bottom plate 21b of the third housing 21 include intake ports 63a and 63b, respectively. The intake ports 63a and 63b are of an opening shape larger than the intake ports 61a and 61b of the fan case 53, and oppose the intake ports 61a and 61b, respectively. The intake ports 63a and 63b are covered with a mesh guard 64 to prevent entrance of a foreign substance, such as a clip.
As shown in
The first through third heat-radiating blocks 51a, 51b, and 51c are provided to the first through third discharge ports 62a, 62b, and 62c of the fan case 53, respectively. Each of the first through third heat-radiating blocks 51a, 51b, and 51c includes a plurality of plate-shaped heat-radiating fins 67. The heat-radiating fins 67 are made of a metal material having excellent heat conductance, for example, aluminum alloy. The heat-radiating fins 67 are provided in parallel at regular intervals, and are fixed to the opening edges of the first through third discharge ports 62a, 62b, and 62c of the fan case 53.
The first through third heat-radiating blocks 51a, 51b, and 51c are thereby positioned to surround the impeller 54 of the fan 50 in three directions. Cooling air discharged through the first through third discharge ports 62a, 62b, and 62c of the fan 50 then passes through the heat-radiating fins 67 of the first through third heat-radiating blocks 51a, 51b, and 51c.
The pipe 52 of the heat-radiating portion 32 is made of a metal material having excellent heat conductance, for example, aluminum alloy. As shown in
As shown in
The second connecting path 71b connects the intake ports 39 of the pump 31 and the coolant outlet 69 of the heat-radiating portion 32. The second connecting path 71b is led to the third convex hollow portion 8c of the first housing 4 from the pump 31 and further to the coolant outlet 69 of the heat-radiating portion 32 through the coupling portion of the convex hollow portion 8c at the other end and the third housing 21.
Both the first and second connecting paths 71a and 71b are flexible paths made of rubber or synthetic resin. Hence, even when there is a change in the positional relation between the pump 31 and the heat-radiating portion 32 in association with rotations of the third housing 21, the first and second connecting paths 71a and 71b undergo deformation, thereby absorbing warping of the circulating path 33.
The pump chamber 38 of the pump 31, the pipe 52 of the heat-radiating portion 32, and the circulating path 33 are filled with cooling liquid used as liquid coolant. Used as the cooling liquid is antifreeze liquid made of, for example, water added with an ethylene glycol solution, and a corrosion inhibitor when necessary. The cooling liquid absorbs heat generated in the IC chip 13 while it circulates in the pump chamber 38 of the pump 31.
As shown in
The third housing 21 accommodates a reserve-tank 80. The reserve-tank 80 replenishes the cooling liquid for a loss by evaporation, and reserves a predetermined quantity of the cooling liquid. The liquid level L of the cooling liquid inside the reserve-tank 80 is positioned higher than the center of the reserve-tank 80, and there is an air layer 81 in contact with the liquid level L of the cooling liquid, in the upper portion inside the reserve-tank 80. The air layer serves to compensate for environmental changes as for example temperature and pressure changes that the apparatus may be subjected to experiencing.
As shown in
Both the outflow portion 74 of the first path 73a and the inflow portion 75 of the second path 73b open inside the reserve-tank 80. The outflow portion 74 of the first path 73a is positioned in the vicinity of the bottom of the reserve-tank 80 below the liquid level L of the cooling liquid.
The end portion of the second path 73b on the inflow side is bent at right angles inside the reserve-tank 80, and runs across above the outflow portion 74 of the first path 73a. The outflow portion 74 of the first path 73a and the inflow portion 75 of the second path 73b are thereby oriented to different directions inside the reserve-tank 80.
The inflow portion 75 of the second path 73b is positioned preferably at, optionally near, the center of the reserve-tank 80. In the case of this embodiment, because the reserve-tank 80 is of a square box-shape, as shown in
As shown in
In the arrangement as descried above, the IC chip 13 of the CPU 11 generates heat while the portable computer 1 is operating. Because the IC chip 13 is thermally connected to the heat-receiving surface 42 of the pump housing 35, heat generated in the IC chip 13 is conducted to the pump housing 35. The pump chamber 38 of the pump housing 35 is filled with the cooling liquid, and the cooling liquid absorbs most of the heat generated in the IC chip 13 and conducted to the pump housing 35.
When the impeller 34 of the pump 31 starts to rotate, the cooling liquid inside the pump chamber 38 is sent to the heat-radiating portion 32 via the first connecting path 71a through the discharge port 40, and the cooling liquid is forced to circulate between the pump chamber 38 and the heat-radiating portion 32.
To be more specific, the cooling liquid heated by heat-exchange in the pump chamber 38 is sent to the first path 73a of the heat-radiating portion 32 via the first connecting path 71a, and thereby flows toward the reserve-tank 80 via the first path 73a. The cooling liquid is then discharged into the reserve-tank 80 through the outflow portion 74 of the first path 73a.
In a case where air bubbles are contained in the cooling liquid flowing in the first path 73a, the air bubbles are released into the cooling liquid reserved in the reserve-tank 80. The air bubbles then rise upward in the cooling liquid inside the reserve-tank 80, and are eventually collected into the air layer 81 in the upper portion of the reserve-tank 80. It is thus possible to separate and remove the air bubbles mixed in the cooling liquid inside the reserve-tank 80.
Because the inflow portion 75 of the second path 73b is immersed in the cooling liquid reserved in the reserve-tank 80, it takes in the cooling liquid inside the reserve-tank 80. The cooling liquid is then led to the pump chamber 38 of the pump 31 from the second path 73b via the second connecting path 71b. The first and second paths 73a and 73b of the heat-radiating portion 32 thus form part of the circulating path 33 used to circulate the cooling liquid between the pump 31 and the heat-radiating portion 32.
The first and second paths 73a and 73b, in which the cooling liquid flows, penetrate through the heat-radiating fins 67 of the first through third heat-radiating blocks 51a, 51b, and 51c, while being thermally connected to the heat-radiating fins 67. Heat generated in the IC chip 13 and absorbed in the cooling liquid is thereby delivered to the heat-radiating fins 67 while the cooling liquid flows through the first and second paths 73a and 73b.
The first through third heat-radiating blocks 51a, 51b, and 51c are provided to the three discharge ports 62a, 62b, and 62c of the fan 50, respectively, and surround the impeller 54 in three directions. Hence, when the impeller 54 starts to rotate, cooling air discharged through the discharge ports 62a, 62b, and 62c passes through the heat-radiating fins 67 and is also blown toward the first and second paths 73a and 73b. The heat generated in the IC chip 13 and conducted to the heat-radiating fins 67 and the first and second paths 73a and 73b is thereby carried away on a flow of air.
The cooling liquid cooled by heat-exchange in the heat-radiating portion 32 returns to the pump chamber 38 of the pump 31 via the second connecting path 71b. The cooling liquid then absorbs heat generated in the IC chip 13 again in the pump chamber 38, after which it is sent to the heat-radiating portion 32. As a result, heat generated in the IC chip 13 is transferred successively to the heat-radiating portion 32 by means of the circulating cooling liquid, and is released to the outside of the portable computer 1 from the heat-radiating portion 32.
In the portable computer 1 arranged in this manner, for example, when the display unit 3 is rotated from the first position to the second position or the third position, or when the portable computer 1 is carried along or transported, the posture of the third housing 21 accommodating the reserve-tank 80 or the portable computer 1 itself is changed. Accordingly, as shown in
According to the above arrangement, the in flow portion 75 of the second path 73b that takes in the cooling liquid reserved in the reserve-tank 80 opens in the cooling liquid at the position corresponding to the center of the reserve-tank 80. The inflow portion 75 of the second path 73b thus remains below the liquid level L of the cooling liquid even when the posture of the reserve-tank 80 is changed, and remains immersed in the cooling liquid.
Hence, the inflow portion 75 of the second path 73b will never open to the air layer 81 inside the reserve-tank 80, which makes it possible to prevent air from entering into the inflow portion 75 of the second path 73b. This prevents the cooling liquid from getting mixed with air bubbles while it is circulating back to the pump chamber 38 of the pump 31 from the reserve-tank 80. Heat generated in the CPU 11 can be thus absorbed by the cooling liquid in a satisfactory manner.
Further, according to the above arrangement, mixing of air bubbles into the cooling liquid can be prevented by a simple arrangement, that is, by merely positioning the inflow portion 75 of the second path 73b at the center of the reserve-tank 80. This eliminates the need to additionally provide a complex air-liquid separating mechanism to the reserve-tank 80, and simplifies the structure of the cooling apparatus 30, thereby making it possible to save the cost.
It should be appreciated that the invention is not limited to the embodiment above, and the invention can be modified in various manners without departing from the scope of the invention. For example, the reserve-tank was accommodated in the third housing of the supporting member in the embodiment above; however, the invention is not limited to this arrangement, and the reserve-tank may be accommodated in the first housing of the body unit.
Further, the reserve-tank is not necessarily shaped like a box, and the reserve-tank may be of a cylindrical shape. In this case, it is preferable that the inflow portion of the second path used to take in the cooling liquid is provided at the intermediate portion of the cylinder in the length direction on the axial center of the cylinder.
Also, the pump housing of the pump served also as the heat-receiving portion in the embodiment above; however, the pump and the heat-receiving portion may be separated from each other and provided as independent components.
| Number | Date | Country | Kind |
|---|---|---|---|
| P2003-147804 | May 2003 | JP | national |
