HEAT SUN EQUIPPED WITH FAN
Patent Information
- Authority / Receiving Office
- DE · DE
- Patent Type
- Patents
- Current Assignee / Owner
- LOTUS THERMAL SOLUTION INC
- Filing Date
- 2019-09-04
- Publication Date
- 2026-07-02
Abstract
Description
TECHNICAL AREA
[0001] The present invention relates to a heat sink equipped with a fan, suitable for dissipating heat from components that generate a large amount of heat. The components include a central processing unit (CPU) and an element used in an electronic device such as a computer or a projector. STATE OF THE ART
[0002] In recent years, the heat generation of CPUs, components, and the like in electronic devices has increased, while at the same time, compact and thin housings have been required. In this context, there is a need for a heat sink that is compact and exhibits high heat dissipation efficiency. For example, patent documents 1 and 2 each proposed a heat sink with reduced thickness and increased heat dissipation efficiency, equipped with a fan, in which heat dissipation fins are arranged around a centrifugal fan. Specifically, several plate-shaped fins with gaps between them are arranged in an up-down direction around the centrifugal fan, allowing air to flow through the gaps and thus dissipating heat.
[0003] Here, each plate-shaped fin must have a predetermined thickness for heat conduction and strength, and the number of plate-shaped fins that can be arranged in an up-down direction is limited. Considering the above, each plate-shaped fin must be large and wide to increase heat dissipation efficiency. Even if a reduction in thickness is possible, the surface area in the lateral direction increases accordingly, and thus an increase in the size and weight of the housing cannot be avoided. To achieve heat dissipation efficiency, it is important to position each heat dissipation fin as close as possible to an outer surface of the centrifugal fan where an exhaust opening is located. Depending on the type of centrifugal fan, machining of the shape of the section opposite the outer surface is required, which can also lead to an increase in costs.
[0004] Furthermore, for quiet operation of the centrifugal fan, in addition to high heat dissipation efficiency even at slow speeds, it is important that the airflow between the heat dissipation vanes around the fan is uniform. In particular, if the airflow can be made uniform, the heat dissipation effect can be maintained even with a low average airflow; and if the average airflow can be reduced, the fan noise will also be reduced. In the case of a heat dissipation vane with an annular shape in plan view, as shown in patent document 2, the airflow can be made uniform. However, in the case of a quadrilateral or other modified shape, the airflow becomes uneven, which can lead to noise or reduced heat dissipation efficiency.If the shape of the heat dissipation fin is limited to a ring shape, as in patent document 2, the limited space within the housing of an electronic device cannot be used efficiently. This can lead to reduced design freedom for the housing. CONSENT LIST [PATENT DOCUMENTS]
[0005] [PTL 1] Unaudited Japanese Disclosure No. 2007-234957 [PTL 2] Unaudited Japanese Disclosure No. 2006-279004 SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION
[0006] In view of the situation described above, an object of the present invention is to create a heat sink equipped with a fan that can be made thin and compact overall; that has high heat dissipation efficiency; that can maintain low noise by preventing the increase in the rotational speed of a centrifugal fan; that does not require special processing according to the external shape of a centrifugal fan; that can be realized at low cost; and that can prevent the occurrence of noise and the decrease in heat dissipation efficiency without specifically restricting the overall shape in plan view to a circular shape, thereby obtaining a shape that corresponds to a space in the housing of an electronic device and maintaining design freedom for the housing. SOLUTION TO THE PROBLEMS
[0007] In light of the current situation, the inventors of the present invention conducted a thorough investigation and conceived the following configuration. That is, a plate-shaped wall, obtained by cutting a porous, lotus-type metal body formed according to a metal hardening process and having multiple pores extending in one direction, is provided around a centrifugal blower instead of the conventionally proposed heat dissipation fins. Air discharged from the centrifugal blower is passed through the pores with a specific airflow resistance, thereby dissipating heat.Even if, in this configuration, the external shape of the entire heat sink, including the plate-shaped wall and heat-absorbing substrate, is not circular in a top view, the flow rate passing through the pores around the fan is made uniform, and the occurrence of noise and a decrease in heat dissipation efficiency can be prevented. Thus, the heat sink can have various external shapes, and the limited space in the housing of the electronic device can be used efficiently for heat dissipation. Furthermore, the inventors of the present invention found that even a plate-shaped wall that is not a porous, lotus-type metal body but has through-holes similar to the pores described above produces similar effects, thereby completing the present invention.
[0008] That is to say, the present invention comprises the following invention. (1) A heat sink equipped with a fan, comprising: a heat-absorbing substrate made of metal, having on one side of its lower surface a contact area intended to be touched by a cooling target in order to absorb heat from the cooling target through the contact area; a centrifugal fan arranged on one side of the upper surface of the heat-absorbing substrate, which is a side opposite the contact area; and a plate-shaped metal wall provided in such a position on an upper surface of the heat-absorbing substrate; and having several through-holes open in a plate surface opposite the centrifugal fan, the position being opposite an outer circumferential section having an air outlet opening of the centrifugal fan. (2) The heat sink equipped with a blower according to (1), wherein plate-shaped walls enclosing the plate-shaped wall are provided continuously over an entire circumference around the centrifugal blower or are provided partially with a space provided therein around the centrifugal blower. (3) The heat sink equipped with a blower according to (1) or (2), wherein the plate-shaped wall is a plate element formed separately from the heat-absorbing substrate, and an end face of the plate element adjacent to a plate surface thereof is joined to the upper surface of the heat-absorbing substrate, thereby providing the plate-shaped wall to stand upright. (4) The heat sink equipped with a blower according to (3), wherein the plate element is obtained by cutting a porous metal body of lotus type having several pores extending in one direction and formed by forming according to a metal strengthening process in a direction that intersects the one direction in which the pores extend, and the pores divided by the cutting serve as through holes in the plate-shaped wall. (5) The heat sink equipped with a blower according to (4), wherein a skin layer in which the pores are not present due to an inner wall of a mold used in the forming is formed in an end section of the plate element and the end section of the plate element in which the skin layer is formed is joined to the upper surface of the heat-absorbing substrate, thereby providing the plate-shaped wall so that it stands. (6) The heat sink equipped with a blower according to any one of points (1) to (5), which has a cover element fixed at an upper end of the plate-shaped wall and designed to close a space on an inside of the plate-shaped wall in which the centrifugal blower is arranged, the cover element having an air inlet hole at a position corresponding to an air inlet connection of the centrifugal blower. ADVANTAGEOUS EFFECTS OF THE INVENTION
[0009] According to the heat sink of the present invention, which is equipped with a fan, heat transferred from the heat-absorbing substrate to the plate-shaped wall is dissipated to the air as air discharged from the centrifugal fan flows through several openings in the wall. This significantly increases the heat dissipation efficiency compared to a case where air is passed between conventional fins. Consequently, the plate-shaped wall can also be made smaller compared to conventional heat-dissipation fins, allowing the entire heat sink to be thinner and more compact. Furthermore, low noise levels can be maintained by preventing an increase in the rotational speed of the centrifugal fan. That is, the high heat dissipation efficiency allows the fan speed to be reduced to slow the flow rate, thus reducing noise.
[0010] Heat dissipation occurs through the through-holes in the plate-shaped wall. Consequently, the flow rate through these holes around the fan remains uniform even if the overall shape of the heat sink, including the plate-shaped wall and the heat-absorbing substrate, is not perfectly circular when viewed from above. This prevents noise and reduces heat dissipation efficiency. Therefore, the heat sink can have various external shapes, allowing for efficient use of the limited space within the electronic device housing and maintaining design freedom for the housing. Furthermore, the heat sink requires no special processing based on the external shape of the centrifugal fan and can thus be manufactured at a low cost. List of characters [ Fig. 1] Fig. Figure 1 is an expanded perspective view showing a heat sink equipped with a fan according to a representative embodiment of the present invention. [ Fig. 2] Fig. Figure 2 is a perspective view of the heat sink equipped with a fan, viewed from below. [ Fig. 3] Fig. Figure 3 is a stretched perspective view of the heat sink equipped with a fan, with one cover element removed. [ Fig. 4] Fig. Figure 4 is a vertical sectional view of the heat sink equipped with a fan. [ Fig. 5] Fig. Figure 5 is a stretched perspective view showing a variation of the heat sink equipped with a fan. [ Fig. 6] Fig. Figure 6 is a stretched perspective view showing a further variation of the heat sink equipped with a fan. [ Fig. 7] Fig. Figure 7 is an expanded perspective view of yet another variation of the heat sink equipped with a fan. [ Fig. 8] Fig. Figure 8 shows an analysis model used in a computational simulation, in the example. [ Fig. 9] Fig. Figure 9 shows an analysis result in the example. DESCRIPTION OF EXECUTION FORMS
[0011] Next, an embodiment of the present invention will be described with reference to the accompanying drawings.
[0012] As it is in Fig. 1 to Fig. Figure 4 shows a heat sink equipped with a fan. 1 according to a representative embodiment of the present invention, a heat absorption substrate 2, a centrifugal blower 3 , plate-shaped walls 4 and a lid element 5 The heat absorption substrate 2 It is made of metal and includes a contact surface on the side of its lower surface. 20 , which is to be touched by a cooling target (not shown) in order to absorb the heat generated from it. The centrifugal fan 3 is on one side of the upper surface 21 of the heat absorption substrate 2 arranged, which form the contact surface 20 The opposite side is... The plate-shaped walls 4 They are made of metal and are positioned on the upper surface. 21 of the heat absorption substrate 2 standing around an outer circumferential section that contains an air outlet opening of the centrifugal blower 3 exhibits, around and opposite this. In each plate-shaped wall 4 are several through holes41 formed, which are embedded in a plate surface 40 compared to the centrifugal blower 3 are open. The lid element 5 is at an upper end 42 the plate-shaped wall 4 fixes and closes off a space s1 on the inside of the plate-shaped wall, in which the centrifugal blower is located 3 is arranged.
[0013] The lid element 5 has an air intake opening 50 at a position that corresponds to an air intake opening 30 of the centrifugal blower 3 corresponds. As with arrows in Fig. As shown in section 4, outside air is drawn in through the air intake opening. 50 of the lid element 5 and the air intake opening 30 of the centrifugal blower 3 Forced. Then the air is forced from the outer circumference of the centrifugal blower. 3 outwards into the room s1 on the inside of the plate-shaped wall4 handed in and then continued through the passage holes 41 the plate-shaped wall 4 Released to the outside. The air from the centrifugal blower. 3 is according to the speed of the centrifugal blower 3 omitted in a direction that is inclined towards the direction of rotation with respect to the radial direction.
[0014] The centrifugal blower 3 The released air enters the through-holes. 41 the plate-shaped wall 4 one, while it absorbs heat that accumulates in the upper surface 21 of the heat absorption substrate 2 , the surface of the slab on the inside of the slab-shaped wall 4 and the space s1 has collected. Then the air is released to the outside, while it continues to transfer heat to the plate-shaped wall. 4 absorbed from the inner wall of each through-hole.
[0015] That is, the plate-shaped wall4 is a heat dissipation wall, and the heat absorption substrate 2 and the plate-shaped wall 4 They form a heat sink that dissipates heat into the air. Since heat is lost during a process in which air passes through several openings... 41 the plate-shaped wall 4 Because the air flows freely and is released into the air, the heat dissipation efficiency can be significantly increased compared to a conventional case where air is forced through between the fins. This is due to the presence of multiple openings. 41The air contact area per unit volume can be several dozen times larger compared to conventional heat dissipation fins, thus significantly increasing the heat dissipation efficiency. Therefore, the plate-shaped wall can be made smaller compared to conventional heat dissipation fins, the entire heat sink can be made thinner and more compact, and low noise levels can be maintained without increasing the speed of the centrifugal fan. 3 to increase.
[0016] The heat absorption substrate 2 It has the form of a solid, flat metal plate. However, the present invention is in no way limited to this configuration. A heat-absorbing substrate 2 A convex lens shape, such that the heat transfer resistance is reduced from a central section to an end section, is also preferred. Furthermore, the heat absorption substrate can be 2It should be hollow rather than solid, and it is also preferred that a hollow section be shaped like a heat pipe. Materials such as aluminum, iron, and copper can be used, as with a conventional heat sink.
[0017] In the present example, the heat absorption substrate is 2 in a top view formed in a rectangular shape and the contact surface protruding in a block shape 20 is located in a central section and four corner sections of the lower surface of the heat absorption substrate. 2 The contact surface can be designed to have a shape that allows close contact with the cooling target, depending on the surface to be added. A known thermally conductive grease (heat-conducting grease) with excellent thermal conductivity is preferably applied between the contact surface as needed. 20 and arranged according to the cooling target.
[0018] As a centrifugal blower 3 Those suitable for conditions such as air volume, dimensions, and the like, such as a Sirocco blower and a turbofan, can be widely used according to the cooling objective, mounting environment, and the like. The centrifugal blower 3 is attached to the upper surface with an adhesive, a screw or the like 21 of the heat absorption substrate 2 Assembled. A high temperature of a blower motor of the centrifugal blower. 3 due to the absorption of heat from the heat-absorbing substrate 2 This can lead to a reduction in the lifespan of the blower. In such a case, it is also desirable to use a spacer element with a lower thermal conductivity than that of the heat-absorbing substrate. 2 between the blower motor and the heat-absorbing substrate 2 to provide, which makes it difficult to transfer heat from the heat-absorbing substrate. 2to transfer to the blower motor.
[0019] Each slab-shaped wall 4 is a plate element that is separate from the heat absorption substrate 2 is formed as a metal material that forms the plate-shaped wall. 4 Materials used for a plate-shaped fin of a conventional heat sink, such as aluminum, iron, and copper, can be widely used, as in the case of the heat absorption substrate. 2 The plate-shaped wall 4 is provided in such a way that they can be joined together by assembling an end face 43 , which is adjacent to the plate surface of the plate element, with the upper surface 21 of the heat absorption substrate 2 It stands. A known method for joining metals, such as brazing or sealing, can be used as a joining process. Although the plate-shaped wall 4of the present example, separate from the heat absorption substrate 2 Given its formation, it is understood that the plate-shaped wall 4 using a mold or the like, integrally with the heat-absorbing substrate 2 It can be formed in this way. In this case, the plate-shaped wall can be processed with through-hole drilling after being formed in one piece.
[0020] In the present example, the plate element described above, which forms the plate-shaped wall, is used. 4The porous, lotus-type metal body, having multiple pores extending in one direction and formed according to a metal strengthening process, is obtained by cutting it in a direction that intersects the single direction in which the pores extend. The porous, lotus-type metal body can be formed according to a known method such as a compressed gas process (e.g., a method disclosed in Japanese Patent No. 4235813) or a thermal decomposition process. The pores divided by the cutting serve as through-holes. 41 the plate-shaped wall 4 .
[0021] The metallic plate-shaped wall 4 with the through holes 41 It can be provided easily and cost-effectively by using the plate element cut from the porous, lotus-type metal mold. In addition, a skin layer is... 45, in which the pores are not present due to an inner wall of a mold used in the forming process, in a circumferential end section of each plate element cut from the porous, lotus-type metal mold body. The end section (the end face) 43 ) of the plate element in which the skin layer 45 is formed, is with the upper surface 21 of the heat absorption substrate 2 joined together so that the plate element stands upright, thus creating a joint between the end face 43 and the upper surface 21 The heat-absorbing substrate is ensured and sufficient bond strength can be maintained. Furthermore, heat transfer from the heat-absorbing substrate can be minimized. 2 on the panel element (the panel-shaped wall) 4 ) efficiently and thus the heat dissipation efficiency can be further improved.
[0022] The thickness of the panels, their shape (fixed panel thickness / variation of the tapered shape, etc.) and the size of the panel-shaped wall. 4 , the axial direction (presence / absence and direction of inclination with respect to the normal of the plate surface 40 ), diameter (average), number per unit area and opening rate (porosity) of the through holes 41 and the like can be set to suitable values, taking into account thermal design, noise, and the like. If air enters a through-hole 41 When air enters, the flow rate increases, and if air escapes from the through-hole... 41 As the flow rate drops, so does the flow rate. If the flow rate changes rapidly, a microscopic Karman vortex often forms, causing noise. Suitable values can be determined by considering this in conjunction with the thermal design.
[0023] In particular, the axial direction of each through hole is 41 preferably fixed in a direction that is relative to the normal of the plate surface 40 It is inclined in the same direction as the direction of rotation of the blower, as this further reduces noise. The through-hole 41 can be drilled using mechanical processes such as drilling.
[0024] The lid element 5 will be moved to the upper end 42 every slab-shaped wall 4 glued to fill the space s1 on the inside of the plate-shaped walls 4 to close, thereby preventing air from escaping and allowing efficient air intake into the air inlet opening. 30 of the centrifugal blower 3 This is made possible. A cost-effective, lightweight resin mold can be used as a lid element. 5 can be used. It is understood that the lid element 5It may be made of a different material than the one mentioned above. The lid element 5 can be made of metal and form a heat sink that is separated from the plate-shaped wall 4 dissipates transferred heat.
[0025] Fig. Figure 5 shows a variation in which the plate-shaped walls 4 intermittently with a gap (slit) 11 ) in between around the centrifugal blower 3 are provided. Thus, in the present invention, it is not necessary to provide the plate-shaped walls. 4 continuously across the entire circumference of the centrifugal blower 3 to provide as in the representative example in Fig. 1 to Fig. 4. The present invention also includes a configuration in which the plate-shaped walls 4 as in Fig. 5 are partially provided.
[0026] If the column 11are provided, the heat absorption substrate 2 on the plate-shaped walls 45 Heat transferred by an airflow through the through holes 41 as described above, and relatively cool air is drawn off, which does not enter the through-holes. 41 flowing through, is drawn from the gaps 11 released, allowing the cool air to be supplied to the surrounding sections for cooling. Particularly in cases where a cooling target, such as a CPU within the housing of an electronic device, is to be cooled by the existing heat sink, other electronic components, etc., are also present that require cooling. Therefore, the columns 11 , in which the plate-shaped wall 4 is not present, as provided in the present example, so that cool air can be sent to locations for such components.
[0027] In the present example, the plate-shaped walls are 4 , which are in the spaces between them, as it says in Fig. As shown in section 5, to keep a holding frame stable 44 provided, which formed the upper ends of the plate-shaped walls 4 couples. Instead of the column 11 by providing the plate-shaped walls 4 To form them with the spaces in between, cutouts or holes larger than the heat dissipation through-holes may be provided in part of a single plate-shaped wall, creating gaps or openings that correspond to the gaps. 11 are similar and, as seen, allow cool air to pass through.
[0028] Fig. Figure 6 shows a modification in which the outer shape of the heat sink, including the plate-shaped wall, 4The heat sink is circular in a top view. The outer shape of the heat sink does not necessarily have to be rectangular in a top view and can be circular, as in the present example, polygonal, or of another shape. Such a circular or other shape can be easily formed by curving the plate element. Fig. Figure 7 shows a variation in which the plate-shaped walls 4 are provided in such a way that they form double, triple or multiple walls with a gap 12 between them in a radial direction (inside and outside). Accordingly, the heat dissipation effect can be slightly increased.
[0029] The above modifications can be combined to achieve various implementations. That is to say, although not shown, the inner and / or outer wall of double-panel walls can be provided as a single wall with perimeter gaps, allowing relatively cool air to enter the surrounding area. For example, both the inner and outer walls can be provided as panel walls with gaps, and the positions of the panel walls can be staggered perimeter so that the panel walls alternate.
[0030] The embodiment and variations of the present invention have been described above. However, the present invention is not limited to these embodiments and variations and can, of course, be implemented in various forms without deviating from the core of the present invention. Example
[0031] Using a calculation simulation and using the heat sink equipped with a fan in the in Fig. 1 to Fig. In the representative embodiment shown in Figure 4, the flow rate passing through the pores around the blower was analyzed as a model and confirmed to be uniform, even though the external shape of the entire heat sink, including the plate-shaped walls and the heat-absorbing substrate, was not circular in a top view. One result of the analysis is described below. (Analysis model)
[0032] A in Fig. Model 8 shown was used. A lid element (not shown) with an open upper suction port was used to close the model.
[0033] Inner diameter of the upper suction port (air inlet hole): ϕ 60 mm Plate-shaped wall (plate element): Inside: four panel elements measuring 30 mm (height: vertical) × 70 mm (length) × 3 mm (thickness) Exterior: four panel elements measuring 30 mm (height: vertical) × 80 mm (length) × 3 mm (thickness) Gap between inner and outer plate element: 2 mm Inner diameter (average) of the through-hole: ϕ 1.05 mm, porosity 60%. Centrifugal blower: It was assumed that air is discharged from individual planes of a regular sixteen-sided polygon through air outlets provided at 16 equal intervals. It was assumed that the discharge direction of each plane is inclined towards the direction of rotation. In particular, it was assumed that air is discharged in an oblique direction inclined at 30° towards the direction of rotation with respect to the normal direction of the plane. (Calculation simulation software)
[0034] The “Flow Designer 2018” software, manufactured by Advanced Knowledge Laboratory Inc., was used. (Analysis result)
[0035] As it is in Fig. As shown in Figure 9, essentially uniform flow rates through the pores were obtained. (Discussion)
[0036] The flow rate decreases as the flow from the centrifugal fan is further away from the fan's outer circumference, due to the increasing volume of the space. In the case of a rectangular shape in a top view, as in the present model, the flow rate at each side section (near the center of each plate-shaped wall) is high, which is relatively close to the centrifugal fan, while the flow rate at each corner section is lower than that at the side section. However, at the corner section, air is drawn to the corner section as if through a fluid funnel. Consequently, air can be made to flow into the pores at a higher rate than the flow rate in an unbounded space. That is, similar flow rates through the pores can be achieved at both the side sections and the corner sections.This result shows that the flow rate passing through pores can be made uniform even when the fan-equipped heat sink has different shapes depending on the device on which the fan-equipped heat sink is installed, and thus the heat dissipation efficiency can be improved. Reference symbol list 1 Heat sink 2 Heat absorption substrate 3 centrifugal blowers 4 Panel-shaped wall 5 lid element 11 column 12 columns 20 contact area 21 Upper surface 30 Air intake opening 40 plate surface 41 Through hole 42 Upper end 43 Front surface 44 mounting frames 45 skin layer 50 air intake holes s1 room QUOTES INCLUDED IN THE DESCRIPTION
[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature
[0000] JP 2007234957
[0005] JP 2006279004
[0005] JP 4235813
[0020]
Claims
[1] Heat sink equipped with a fan, comprising the following: a heat absorption substrate made of metal and having on one side of its lower surface a contact area which is to be touched by a cooling target in order to absorb heat from the cooling target through the contact area; a centrifugal blower arranged on one side of the upper surface of the heat-absorbing substrate, which is one side opposite the contact area; and a plate-shaped metal wall, positioned on an upper surface of the heat-absorbing substrate; and having multiple through-holes open in a plate surface opposite the centrifugal blower, the position being opposite an outer circumferential section having an air outlet opening of the centrifugal blower. [2] Heat sink equipped with a blower according to claim 1, wherein plate-shaped walls comprising the plate-shaped wall are provided continuously over an entire circumference around the centrifugal blower or are provided partially with a space therein around the centrifugal blower. [3] Heat sink equipped with a fan according to claim 1 or 2, wherein the plate-shaped wall is a plate element that is formed separately from the heat absorption substrate, and An end face of the plate element, adjacent to a plate surface thereof, is joined to the upper surface of the heat absorption substrate, thus providing the plate-shaped wall to stand upright. [4] Heat sink equipped with a blower according to claim 3, wherein the plate element is obtained by cutting a porous, lotus-type metal body, having multiple pores extending in one direction and formed by shaping according to a metal strengthening process, in a direction that intersects the one direction in which the pores extend, and The pores divided by the cutting serve as passage holes in the plate-shaped wall. [5] Heat sink equipped with a blower according to claim 4, wherein a skin layer in which the pores are not present due to an inner wall of a mold used in the forming process, is formed in an end section of the plate element and the end section of the plate element, in which the skin layer is formed, is joined to the upper surface of the heat absorption substrate, thus providing the plate-shaped wall in such a way that it stands. [6] Heat sink equipped with a fan according to any one of claims 1 to 5, comprising: a cover element fixed to an upper end of the plate-shaped wall and designed to close a space on an inside of the plate-shaped wall in which the centrifugal blower is arranged, the cover element having an air inlet hole at a position corresponding to an air inlet port of the centrifugal blower.