JP2005223124A - Heat sink and electronic apparatus equipped with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat sink of high heat radiation capacity and cooling efficiency, having low noise, and to provide an electronic apparatus with the heat sink mounted thereon. <P>SOLUTION: In the heatsink, the heat of a cooled object is received by a heat-receiving part through a refrigerant liquid and is sent to a heat radiating part for heat radiation. The heat radiating part 3 comprises a centrifugal fan 4 provided with a pair of noses facing, and protruding toward an impeller and with a double volute for discharging in the facing direction, and a pair of heat radiation fin arrays which are provided to discharge the paths of the double volute with a plurality of heat radiation fins, arranged along a discharge flow for radiating the heat of the refrigerant liquid. Thus, the center of the impeller is not aligned with the straight line connecting the pair of noses, and the phase of pressure fluctuation, generated by each nose when the impeller spins, is distributed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a heat dissipating device that dissipates heat of a heat-generating component such as a semiconductor integrated circuit by a fan and a heat dissipating fin array while circulating a refrigerant, and an electronic apparatus including the heat dissipating device.

  The recent trend of speeding up in computers is extremely rapid. For this reason, the amount of heat generated by the central processing unit (CPU) increases, and it is air-cooled with a heat sink as before, and simply ventilating the air inside the housing and the outside air, the cooling capacity is insufficient, high efficiency and high output The cooling system is indispensable. Therefore, conventionally, as a device for cooling the heat generating component, a flow path through which the refrigerant liquid circulates between the heat receiving portion and the heat radiating portion is provided, and in the heat receiving portion, the heat from the heat generating component is absorbed by the refrigerant liquid, and the temperature is increased. The refrigerant liquid that has become higher is transported to the heat radiating part, and the heat of the refrigerant liquid is released in the heat radiating part, so that the temperature of the refrigerant liquid is lowered, the refrigerant liquid is transported to the heat-generating parts again, and the cooling is repeated. (See, for example, Patent Document 1).

  In this conventional heat radiating device, the heat of the refrigerant liquid is transmitted to the surface in the heat radiating section, and air is flowed to the surface to radiate heat to the atmosphere. As a structure of heat radiation to the atmosphere in the heat radiation portion, a large number of plate-like fins are provided on the pipe through which the refrigerant liquid passes, and air is blown by a fan.

In general, in a fan, there has been a technique for reducing noise by causing the wavelengths of pressure waves generated at two locations in a casing to interfere with each other by shifting by half a wavelength in order to reduce the rotational sound of the fan.
Japanese Patent Laid-Open No. 07-142886

  However, when the air is blown to the plate-like fins, the airflow becomes laminar on the surface of the fins, and the heat cannot be efficiently radiated. That is, the heat on the surface of the fin is transmitted only to the air in the thin boundary layer portion of the laminar flow that flows on the fin surface, and the main flow away from the fin surface simply passes through and does not receive heat and does not contribute to heat dissipation. Therefore, if the rotational speed of the fan is increased to increase the amount of air blown, fan noise is generated approximately in proportion to the fourth power of the rotational speed, resulting in an annoying sound when used in an electronic device.

  Thus, increasing the number of rotations and increasing the amount of air flow will cause an increase in noise, and the laminar boundary layer on the fin surface cannot be turbulent, resulting in poor cooling efficiency. When the rotational speed is lowered to reduce the air flow rate, the noise is reduced, but the heat dissipation capability is reduced, and when the heat dissipation capability is increased, the noise increases. Furthermore, even if such a heat dissipation device is subjected to a conventional technique of canceling with a half-wave shift, it does not lead to an improvement in cooling efficiency and heat dissipation capability, and only a reduction in noise can be achieved.

  Therefore, realizing a large air volume, a high heat radiation capacity, and a high efficiency cooling while reducing the noise of the fan has been a problem with a contradiction.

  Accordingly, an object of the present invention is to provide a heat dissipating device having high heat dissipating capability, high cooling efficiency and low noise, and an electronic device equipped with the heat dissipating device.

The heat radiating device of the present invention receives the heat of the object to be cooled by the refrigerant liquid at the heat receiving part, and sends the refrigerant liquid to the heat radiating part provided with the fan and the radiating fin row for radiating the received heat to radiate the heat. A heat dissipating device, wherein the fan includes a centrifugal impeller and a double volute formed with a pair of noses projecting toward the impeller, and each discharge path of the double volute has a row of heat dissipating fins. Pressure fluctuations that occur at each nose when the impeller rotates, with the plurality of radiating fins arranged along the discharge flow, the center of the impeller removed from the position on the straight line connecting the noses The main feature is that the phase of each is dispersed.

  ADVANTAGE OF THE INVENTION According to this invention, while being able to implement | achieve highly efficient cooling with high heat dissipation capability, the low noise heat radiating device and the electronic device carrying it can be provided.

  A first invention made to solve the above problems is a heat radiating portion provided with a fan and a radiating fin array for receiving heat of a cooling object by a refrigerant liquid at the heat receiving portion and radiating the received heat. A heat dissipating device for sending a refrigerant liquid to dissipate heat, wherein the fan comprises a centrifugal impeller and a double volute formed with a pair of noses protruding opposite to the impeller, and the double volute Each discharge path is provided with a row of radiating fins, and the plurality of radiating fins are arranged along the discharge flow. When the impeller rotates when the center of the impeller is removed from the position on the straight line connecting the noses In addition, a heat radiating device in which the phase of the pressure fluctuation generated at each nose is dispersed, has a high heat radiating capability, can realize highly efficient cooling, and can also realize a low noise heat radiating device.

  A second invention of the present invention is an invention dependent on the first invention, wherein the center of the impeller is set so that the phase difference of each pressure fluctuation generated in the nose is 120 °, and each nose is This is a heat dissipation device in which the phase of the peak of the generated pressure fluctuation is evenly distributed, and can be surely made into a heat dissipation device with high heat dissipation capability, high efficiency and low noise.

  The third invention of the present invention is an electronic device in which the first or second heat dissipation device is mounted and the heat receiving portion is in contact with the heat generating electronic component, has a high heat dissipation capability, and realizes high-efficiency cooling. At the same time, it is possible to make electronic devices with low noise and high reliability.

(Example 1)
Embodiment 1 of the present invention relates to a computer device as an electronic apparatus, and relates to a heat dissipation device mounted on the computer device. FIG. 1 is a configuration diagram of a computer device equipped with a heat dissipation device in Embodiment 1 of the present invention.

  In FIG. 1, reference numeral 1 denotes a CPU which is a heat generating component of a computer device, and generates heat in proportion to a clock frequency for operation. Recently, computer devices operating at a high frequency of 1 GHz to 3 GHz class have appeared, and the amount of heat generation is extremely large, and the housing of the computer device has a structure that is compact and easily traps heat.

Reference numeral 2 denotes a heat receiving unit-integrated pump provided with a motor that drives the pump by providing a heat receiving unit on a side surface, absorbing heat from the CPU 1 and exchanging heat with the refrigerant to circulate the refrigerant. The heat receiving unit integrated pump 2 is a turbo pump such as a centrifugal pump or a vortex pump (not shown), and the specifications of the pump have a thickness of 3 mm to 20 mm and a radius so that the pump 1 can be placed on the surface of the CPU 1. Direction representative dimensions 10 mm to 70 mm, rotation speed 600 rpm to 4000 rpm, flow rate 0.01 L / min to 1.5 L / min, head 0.1 m to 2 m, specific speed 12 to 200 (unit: m, m ³ / min, rpm). Further, the side surface opposite to the motor installation side of the heat receiving part integrated pump 2 is formed in a complementary shape with the heat generating component so that heat transfer with high efficiency is possible.

  Reference numeral 3 denotes a heat dissipating part that is made of a metal having good thermal conductivity such as aluminum or copper and takes heat from the refrigerant, and 4 is a centrifugal fan that is provided in the heat dissipating part 3 and forcibly cools the heat dissipating part 3. By driving the fan 4, air is caused to flow in the heat radiating unit 3, and heat is released from the outer surface to the atmosphere. The heat radiating section 3 is provided with a large number of fins in a metal tube serving as a flow path for the refrigerant liquid. By applying air to the fins by the fan 4, the heat of the fins is released into the atmosphere. Reference numeral 5 denotes a reserve tank that stores the refrigerant liquid to be replenished when the refrigerant liquid is reduced, and 7 is a flexible pipe that connects these to form a circulation path. The heat receiving unit integrated pump 2 of the first embodiment is driven at a predetermined set rotational speed set at 600 rpm to 4000 rpm, takes heat through the heat receiving unit brought into contact with the CPU 1, and circulates a refrigerant having a predetermined flow rate. .

  Then, the detailed structure of the thermal radiation part 3 of Example 1 is demonstrated. FIG. 2 is a partially exploded perspective view of the heat dissipating part in the first embodiment of the present invention. In FIG. 2, reference numeral 21 denotes a pipe, which is provided to circulate the refrigerant liquid sent using the pipe 7 inside the heat radiating unit 3. The refrigerant liquid whose temperature has increased by absorbing the heat of the CPU 1 is discharged from the heat receiving integrated pump 2 and enters the heat radiating section 3 as shown in FIG. The refrigerant liquid that has radiated heat at the heat radiating unit 3 and has fallen in temperature is discharged from the heat radiating unit 3, and returns to the heat receiving unit integrated pump 2 again through the pipe 7.

  22a and 22b are a pair of radiating fin rows in which a plurality of aluminum plates are arranged, the pipe 21 is penetrated, and both are thermally coupled. At the discharge port, the radiating fins of the radiating fin rows 22a and 22b are arranged in the direction along the flow. The heat of the refrigerant liquid passing through the pipe 21 is transmitted from the outer surface of the pipe 21 to the radiating fin row 22, and the heat is released to the atmosphere. Each length of the radiation fin rows 22 a and 22 b is formed longer than the diameter of the fan 4.

  Reference numeral 23 denotes a case of the heat radiating portion 3. The case 23 is fixed with a centrifugal fan 3 and radiating fin rows 22a and 22b described later. Reference numeral 24 denotes an impeller of the fan 3 having a motor disposed in the center. The case 23 is a double volute capable of discharging in two opposite directions, and an impeller 24 is provided in the middle of each discharge port. Reference numeral 25 denotes an air inlet opened on the lower surface of the case 23, 26 a cover for covering the impeller 24, 27 an inlet provided in the cover 26, and 28 a flow path of a double volute provided in the case 23. It is the rib which comprises.

  The air sucked from the inlets 25 and 27 of the case 23 and the cover 26 changes its direction in the centrifugal direction by the rotation of the impeller 24, obtains momentum, and is pressurized. The impeller 24 has a number of double volutes (which is the same as the number of noses as will be described later, two in the case of double volute) and a prime number of blades having no common divisor. For example, in FIG. 2, the number of 13 blades is adopted. This is because pressure waves are not generated simultaneously at two locations of the double volute. That is, if the blades generate pressure waves having the same phase at two locations, the two pressure waves propagate and cause interference. However, the prime number of blades does not have the number of double volutes and the common divisor, and therefore does not generate pressure waves at the same time and does not interfere. The air discharged from the impeller 24 flows along the ribs 28 provided in the case 23 into the radiating fin rows 22a and 22b provided in the discharge ports of the double volute. When air passes through the radiating fin rows 22a and 22b, the heat is taken from the radiating fin rows 22a and 22b to cool the refrigerant liquid.

FIG. 3 is a plan view of a case and an impeller provided thereon in Embodiment 1 of the present invention, and FIG. 4 is a plan view of a state in which the first blade is closest to the first nose in Embodiment 1 of the present invention. FIG. 5 is a plan view showing a state in which the second blade is closest to the second nose in the first embodiment of the present invention. In FIG. 3, reference numerals 31 and 32 denote a pair of double volute noses protruding opposite to the impeller 24. The noses 31 and 32 are closest points that are closest to the impeller 24. Each volute for pressure recovery from the noses 31 and 32 is formed. When the impeller 24 rotates counterclockwise as indicated by the arrow, the air is discharged along the ribs 28 in the centrifugal direction and flows out in the left and right directions. And in Example 1, it arrange | positions so that the center of the impeller 24 may come to the position which remove | deviated from the straight line which connects the noses 31 and 32. FIG. Moreover, 24a, 24b, 24c, and 24d shown in FIGS. 4 and 5 are blades of 13 impellers 24, respectively.

  FIG. 4 shows a state in which one blade 24 a of the impeller 24 is closest to the nose 32. In this state, the nose 31 is located between the blade 24b and the blade 24c. More precisely, this position is not the center of the blades 24b and 24c, but the portion between the blades 24c and 24b is divided into approximately 1/3 and approximately 2/3. FIG. 5 shows a state in which the impeller 24 is slightly rotated from the state of FIG. 4 and one blade 24 b of the impeller 24 is closest to the nose 31. In this state, the nose 32 is located between the blades 24a and 24d. More precisely, this position is not the center of the blades 24a and 24d, but the portion between the blades 24d and 24a is divided into approximately 1/3 and approximately 2/3.

  Therefore, the pressure fluctuation generated at the nose described above will be specifically described. FIG. 6 is a graph showing pressure changes in the first and second noses and the impeller in Example 1 of the present invention. In FIG. 6, P 31 indicates a pressure change at the nose 31, and P 32 is a pressure change at the nose 32. The waveforms P31 and P32 are sinusoidal, and one wavelength of the waveforms P31 and P32 is a period from when a blade with the impeller 24 passes through the nose 31 or the vicinity of the nose 32 until the next blade passes. As described above, when one of the blades reaches one of the noses 31 and 32, the other of the noses 31 and 32 divides the space between the two blades into approximately 1/3 and approximately 2/3. Therefore, as shown in FIG. 6, the waveforms P31 and P32 are out of phase by one third. For this reason, the peak of P31 and the peak of P32 do not appear at the same time, and when the waveforms P31 and P32 interfere with each other due to the same phase and the rotation speed is N and the number of blades is Z, the frequency NZ and its high-frequency component are strong. It does not propagate as noise.

  Thus, in the first embodiment, in order to reduce the interference sound of the impeller 24, at least a common divisor is not present between the number of blades Z and the number of noses (two because it is a double volute). Yes. Further, in the first embodiment, the center of the impeller 24 is not placed on a straight line connecting the tips of the noses 31 and 32, and the center is arranged at a position slightly deviated from the center. Thus, when one blade passes through one of the noses 31 and 32, it is prevented that another blade passes through the other of the noses 31 and 32 at the same time. In particular, it is preferable to arrange the impeller 24 and the noses 31 and 32 so that the phase difference between the waveforms P31 and P32 is about 120 °. That is, when such an arrangement is made, the appearance time of a total of four positive and negative peaks of pressure fluctuations in the noses 31 and 32 can be evenly distributed as shown in FIG.

  By the way, conventionally, as one means for noise countermeasures, it has been proposed to shift the wavelengths of two pressure waves by half a wavelength (180 °) and cancel the two to reduce noise. However, with this method, the laminar boundary layer on the fin surfaces of the heat dissipating fin rows 22a and 22b cannot be turbulent, and at least cannot be improved in heat dissipating capacity and cooling efficiency.

  Therefore, in the heat dissipating section 3 of the first embodiment of the present invention, the heat dissipating fin rows 22a and 22b are arranged in the discharge ports of the double volute so that the plurality of fin surfaces are aligned in the flow direction. In this configuration, instead of canceling the pressure fluctuation, the laminar flow boundary layer of the radiating fin is turbulent using the pressure fluctuation (this improves the heat radiating capability and the heat radiating efficiency), and the radiating fin row 22a, At the time of discharging from 22b, noise can be reduced by the rectifying action. Due to pressure fluctuations generated from the moderately controlled noses 31 and 32 and the radiation fin rows 22a and 22b without causing interference, low-rise sound, large air volume, high heat radiation capability, and high efficiency heat radiation can be realized.

  On the other hand, when the pressure waves of the waveforms P31 and P32 are caused to interfere with each other in the same phase, the pressure fluctuation is greatly propagated to the outside of the heat radiating unit 3 and noise is not reduced.

  In order to make the pressure fluctuations that change moderately without interfering with the pressure fluctuations generated at the noses 31 and 32, the appearance times of the four peaks of the waveforms P31 and P32 are evenly distributed, and the distance between the blades and the noses 31 and 32 The strength can be controlled by adjusting. At this time, a regular and moderately large pressure wave is generated, and heat radiation fin arrays 22a and 22b can perform heat radiation and rectification with high efficiency. As a whole, noise reduction, high heat radiation capacity, and high efficiency heat radiation section 3 are obtained. be able to. In the first embodiment, as described above, the center of the impeller 24 is removed from the straight line connecting the tips of the noses 31 and 32, the peak positions are dispersed, and the phase difference between the waveforms P31 and P32 is about 120 °. It constitutes.

  As described above, the heat dissipating device of the first embodiment and the electronic device on which the heat dissipating device is mounted have high heat dissipating capability, can realize highly efficient cooling, and can also realize low noise.

  INDUSTRIAL APPLICABILITY The present invention has a high heat dissipation capability and can realize high-efficiency cooling. In addition, the present invention can be applied to a low-noise heat dissipation device and an electronic device equipped with the same.

1 is a configuration diagram of a computer device equipped with a heat dissipation device in Embodiment 1 of the present invention. 1 is a partially exploded perspective view of a heat radiating portion in Embodiment 1 of the present invention. The top view of the case in Example 1 of this invention and the impeller provided in it The top view of the state in which the 1st blade | wing came closest to the 1st nose in Example 1 of this invention The top view of the state in which the 2nd blade | wing approached the 2nd nose in Example 1 of this invention most closely The graph which shows the pressure change of the 1st and 2nd nose and impeller in Example 1 of this invention

Explanation of symbols

1 CPU
DESCRIPTION OF SYMBOLS 2 Heat receiving part integrated type pump 3 Heat radiation part 4 Fan 5 Reserve tank 7 Piping 21 Pipe 22a, 22b Radiation fin row 23 Case 24 Impeller 25 Inlet 26 Cover 27 Inlet 28 Rib 31, 32 Nose

Claims (3)

A heat radiating device that receives heat of a cooling object by a refrigerant liquid at a heat receiving part, and dissipates heat by sending the refrigerant liquid to a heat radiating part provided with a fan and a radiating fin row for radiating the received heat, The fan includes a centrifugal impeller and a double volute formed with a pair of noses protruding to face the impeller, and the radiating fin row is provided in each discharge path of the double volute. In addition, the plurality of radiating fins are arranged along the discharge flow, the center of the impeller is removed from the position on the straight line connecting the noses, and the pressure fluctuation generated in each nose when the impeller rotates The heat dissipating device is characterized in that the phase is dispersed. The center of the impeller is set so that the phase difference of each pressure fluctuation generated at the nose is 120 °, and the phase of the peak of pressure fluctuation generated at each nose is evenly distributed. The heat dissipation device according to claim 1. An electronic apparatus comprising the heat dissipation device according to claim 1 or 2, wherein the heat receiving portion is in contact with a heat generating electronic component.

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