JP2016086018A - heat sink - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat sink capable of maintaining the cooling efficiency, by suppressing occurrence of pressure loss as much as possible.SOLUTION: A heat sink 100 includes a basis 110, a heat receiving region formed on one surface of the basis 110 and receiving heat generated from a heating element as a heat source, and a plurality of heat dissipation fins 131 formed on the other surface of the basis 110 and dissipating the heat to a coolant fluid 200. The plurality of heat dissipation fins 131 includes first heat dissipation fin group 131a having the tips arranged at a position having the same distance attributes for the geometrical distance of the coolant fluid 200 in the streamline direction, and second heat dissipation fin group 131b having the tips arranged at a position having the distance attributes on the downstream side of the distance attributes to which the first heat dissipation fin group 131a belongs.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a heat sink used for an electronic device, and particularly relates to the shape of a radiation fin.

  For example, in Japanese Patent Application Laid-Open No. 2013-098530 (Patent Document 1), the shape and arrangement of the fins are devised so that the sum of the cross-sectional areas of the flow paths formed by the heat radiating fins increases as the cooling refrigerant advances downstream. Has been.

JP2013-098530A

  However, according to the technology of Patent Document 1, when the cooling refrigerant flows into the heat sink, if the flow passage cross-sectional area there is not sufficiently secured, the pressure loss on the upstream side of the heat sink increases, and as a result As a result, the cooling efficiency is lowered. Moreover, if it is going to widen the space | interval of an upstream radiation fin and ensure a flow-path cross section, the cooling efficiency in the area | region will fall.

  In view of the above problems, the present invention has an object to provide a heat sink that can suppress the generation of pressure loss as much as possible while maintaining the cooling efficiency by a significant fin arrangement.

In order to solve the above problems, the present invention has the following heat sink configuration. That is, a base body, a heat receiving region that receives heat from a heat-generating element as a heat source, and a region formed on one surface of the base body, and the heat amount formed on the other surface of the base body In a heat sink comprising a plurality of heat radiating fins that radiate heat to the fluid,
The plurality of radiating fins are constituted by one radiating fin or two or more radiating fins, an upstream side radiating fin having a tip portion disposed on the most upstream side of the refrigerant fluid, and two or more radiating fins. A downstream side radiation fin having a tip portion disposed downstream of the radiation fin,
The downstream radiating fins are arranged such that tip portions of the radiating fins are arranged at respective portions where pressure losses in the flow paths defined by the upstream radiating fins are substantially matched.

Preferably, a space in which the flow path is formed is a flow path forming space, a cross section perpendicular to the flow line of the refrigerant fluid is a flow path cross section, and the other cross section of the flow path cross section is the other cross section. When the area surrounded by the plane and the reference plane offset from the predetermined part of the plane is the flow path cross-sectional area,
The other surface includes a first region surface provided on the upstream side of the refrigerant fluid, and a flow path cut-off smaller than a channel cross-sectional area provided on the downstream side of the refrigerant fluid and formed by the first region surface. And a second region surface forming an area.

  Preferably, each tip portion of the plurality of radiating fins has a skewed shape in which the shape extending from the fixed end to the other surface to the free end is inclined in the downstream direction of the refrigerant fluid.

  In the heat sink according to the present invention, heat radiation fins are arranged so as to be significant in terms of fluid dynamics, and it is possible to form a preferable refrigerant flow path that balances suppression of pressure loss and maintenance of heat radiation efficiency.

The perspective view of the heat sink concerning an embodiment. The side view of the heat sink which concerns on embodiment. The flow path cross section of the heat sink which concerns on embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view of a heat sink according to the present embodiment. FIG. 2 is a cross-sectional view of the A section in the previous figure. As shown in the figure, the heat sink 100 includes a base body 110 and a plurality of heat radiating fins 131 that are integrally formed of a heat conductive material such as an aluminum material.

  The base body 110 is provided with a space A in which electrical elements and the like are accommodated, and a space B in which a plurality of cooling fins are provided. Hereinafter, the direction in which the space A is observed with reference to the basic body 110 and its surface will be referred to as one surface side or one surface. In addition, the direction in which the space B is observed with reference to the base body 110 and its surface will be referred to as the other surface side or the other surface.

  A heat conductive substrate 302 is laminated on one surface of the base body 110, and a heat generating element 301 such as a power transistor is mounted on the surface thereof. Therefore, when this heat generating element 301 is driven, it becomes a heat source, generates heat, and gives heat to the base body 110 via the heat conductive substrate 302.

  The thermally conductive substrate 302 is appropriately fixed by a substrate frame 302a. Thereby, the transmission path | route to the base body 110 becomes settled, and the heat receiving area | region 120 which receives heat amount of the tip is decided. As described above, the heat receiving region 120 is a region where the heat conductive substrate 302 is laminated, and the heat amount of the heat generating element 301 is transmitted to the base body 110 through the heat receiving region 120. In order to improve this effect, a thermoelectric structure such as heat-dissipating grease may be interposed.

  As shown in the figure, the substrate frame 302a is appropriately provided with a plurality of terminals 302b, and the wiring of the control circuit 303 is electrically connected to the terminals. In the present embodiment, filter capacitors 304 and 305 are mounted on the mounting surface of the control board 303. As described above, the set of electrical elements mounted on the heat sink 100 forms a converter 10 (power converter) such as a DC / DC converter together.

  A plurality of radiating fins 131 coupled to the base body are arranged on the other surface of the base body 110. Each of the plurality of radiating fins 131 is disposed substantially in parallel along the streamline of the refrigerant fluid 200. Each of the heat dissipating fins 131 has a constant plate thickness, and the depth of the refrigerant flow path is determined by the plate width. In the heat radiating fins 131, the heat amount is sequentially transmitted from the base body 110, and the heat amount is radiated to the cooling refrigerant 200. Hereinafter, for the convenience of explanation, with respect to the radiating fin 131, the end portion disposed on the upstream side of the refrigerant fluid is the tip portion, the end portion disposed on the downstream side of the refrigerant fluid is the tail end portion, and the portion coupled to the base body The fixed end and the opposite side will be called the free end. In addition, the refrigerant flow path mentioned above means each flow path divided by the adjacent heat radiating fins.

  As shown in the figure, the plurality of radiating fins 131 are provided with an upstream radiating fin group 131a and a downstream radiating fin group 131b that are aligned at different attributes. The attribute in the present embodiment refers to a common relationship between hydrodynamically significant distance relations, loss coefficients caused by pressure loss, boundary friction, and the like. In the present embodiment, for each refrigerant flow path, a set of points at which the pressure loss is made equal from the front end surface of the heat sink is called a distance relationship that makes the attributes equal.

  The upstream side heat dissipating fins 131a according to the present embodiment have their front end portions aligned on the upstream side of the flow line of the refrigerant fluid. Further, the downstream side radiating fin 131b has a tip portion disposed on the downstream side of the first radiating fin group 131a. That is, in the upstream side heat radiation fin group 131a, the tip portion of the fin is arranged in the heat sink region on the most upstream side of the refrigerant fluid. Further, when the downstream side radiating fin group 131b is arranged downstream of the upstream side radiating fin group 131a, a pressure loss is generated in proportion to the distance flowing down here. The upstream side radiating fin group 131a may be composed of a plurality of fins or a single fin.

  In general, in the pressure state of the fluid, the loss factor varies depending on the shape of the flow cross section and the roughness of the boundary surface. In addition, the sudden expansion cross section or the rapid contraction cross section causes a large pressure loss as compared with a cross section that changes slowly.

  According to the heat sink according to the present embodiment, the radiating fin groups having different attributes are arranged in two stages, so that the passage cross section of the refrigerant fluid gradually changes, and it is possible to suppress the occurrence of pressure loss. . In the present embodiment, a plurality of heat dissipating fin groups having different distance attributes are also provided at the tail end portion of the heat dissipating fins, thereby reducing the pressure loss generated on the outflow side.

  Moreover, about the 2nd radiation fin group 131b, it is good also as a structure of 2 or more in the radiation fin group from which distance attributes differ. According to this configuration, the change in the passage cross section of the refrigerant fluid is further alleviated, and accordingly, the generation of pressure loss can be more effectively suppressed.

  Further, in the downstream side heat radiation fin 131b according to the present embodiment, the arrangement of the front end portion of the downstream side heat radiation fin 131b is determined so that the pressure loss is substantially matched with each front end portion of the upstream side heat radiation fin 131a. . That is, in the present embodiment, the downstream side radiating fins 131b are continuously arranged in a state in which the portions where the pressure loss distributions substantially coincide are connected.

  According to this, since the arrangement of the radiating fins is significant in terms of fluid dynamics, it is possible to form a refrigerant flow path that can suppress the pressure loss to an intended state. Moreover, if it is the range which implement | achieves this, the design which increases the said radiation fin will be attained, and it will contribute also to the design which maintains heat dissipation efficiency as a result. That is, according to the present embodiment, the arrangement of the radiating fins is made so as to be significant in hydrodynamics, and a preferable refrigerant flow path can be formed on the radiating structure that balances suppression of pressure loss and maintenance of radiating efficiency. It becomes possible.

  The distance attribute described above is determined based on the pressure loss, and in explaining the general mode, the state in which the arrangement of the downstream side radiation fins 131b is displaced downstream is introduced. . However, depending on the state of each flow path, the pressure loss at the equidistant downstream point of each flow path starting from the upstream end face of the heat sink may be the same. In such a case, when the distal end portions of the downstream side radiation fins 131b are arranged based on pressure loss, the downstream portion of each downstream side radiation fin 131b has a flow-down distance starting from the upstream end surface of the heat sink. All are arranged at equal positions. That is, the tip part of the downstream side radiation fin 131b in such a case shows an arrangement substantially parallel to the upstream side end face of the heat sink.

  In the present embodiment described with reference to FIG. 2, it has been studied to further devise a flow path through which the refrigerant fluid 200 passes. Before explaining this, the prerequisites for the refrigerant flow path will be specifically described. First, an adjacent space is formed between one fin and a fin adjacent to the portion where the radiating fins are adjacent to each other. With regard to this adjacent space, if an appropriate point on the streamline is an observation point, flow path cross sections 402 and 405 that are perpendicular to the streamline are provided at this observation point. The channel cross section 402 is provided corresponding to a first region surface 501 described later, and the channel cross section 405 is provided corresponding to a second region surface 502 described later.

  According to the figure, the first region surface 501 forms a partial region of the “other surface” and is provided on the upstream side of the refrigerant fluid. The second region surface 502 also forms a partial region of the “other surface”, and is provided on the downstream side of the first region surface 501. The region surfaces 501 and 504 are a flow path of the refrigerant fluid, and each of them forms a continuous plane by the R surface.

  FIG. 3A is a cross-sectional view of the channel cross section 402 observed from the upstream side in the streamline direction. FIG. 3B is a cross-sectional view of the channel cross section 405 observed from the upstream side in the streamline direction. Comparing these, it can be seen that the second region surface 502 has a shallower groove depth from the free end of the radiating fin than that of the first region surface 501.

  3A and 3B show a reference surface 403 that is offset from the first region surface 501 (a predetermined part of the other surface). In any of the drawings, an adjacent space is formed between the radiating fins. In FIG. 3A, one side is bounded by the first region surface 501, and the other side is bounded by the reference surface 403, thereby defining a flow path cross-sectional area 404 a based on the reference surface 403. Further, in FIG. 3B, one side is bounded by the second region surface 502 and the other side is bounded by the reference surface 405, thereby defining a channel cross-sectional area 404b based on the reference surface 403. The

  The reference plane 403 described above indicates an absolute position that is offset from a predetermined portion of the “other surface”, and the position does not change whether it is the first region surface or the second region surface. Therefore, the channel cross-sectional area 404a is larger than the channel cross-sectional area 404b formed by the second region surface 502 due to the groove depth.

  According to such an embodiment, it is possible to design the flow path cross-sectional area to change stepwise with respect to the path from the first region surface 501 to the second region surface 502. Therefore, this merit can be used for the inflow portion to the heat sink, and the loss factor of the refrigerant fluid passing therethrough can be suppressed. Such a shape of the “other surface” can make the pressure loss reduction effect more prominent when provided by being displaced somewhat in the streamline direction from the upstream-side radiating fin or the downstream-side radiating fin. .

  In addition, it is preferable that the above-described radiating fin has a skewed shape in which the shape from the fixed end to the free end is inclined in the downstream direction at the tip portion provided on the upstream side. The tip portion having such a skew shape gradually increases the height component in the downstream direction, thereby contributing to a reduction in the loss factor there. And since the front-end | tip part made into this shape is arrange | positioned in the vicinity of the area | region where the pressure loss reduction | decrease effect mentioned above is given, the further loss reduction effect | action can be anticipated combined with these effects.

  DESCRIPTION OF SYMBOLS 10 Converter, 100 Heat sink, 110 Base body, 120 One side, 121 Heat receiving area, 131 Radiation fin, 131a 1st radiation fin group, 131b 2nd radiation fin group, 200 Refrigerant fluid, 301 Exothermic element, 302 Transmission Thermal substrate, 303 control substrate.

Claims (3)

A base body, a heat receiving region that is formed on one surface of the base body and receives a heat amount using the heat-generating element as a heat source, and the heat amount formed on the other surface of the base body to the refrigerant fluid In a heat sink comprising a plurality of heat dissipating fins for radiating heat,
The plurality of radiating fins are constituted by one radiating fin or two or more radiating fins, an upstream side radiating fin having a tip portion disposed on the most upstream side of the refrigerant fluid, and two or more radiating fins. A downstream side radiation fin having a tip portion disposed downstream of the radiation fin, and
The heat sink according to claim 1, wherein the downstream side heat radiation fin has a front end portion of the heat radiation fin arranged at each position where pressure loss in each flow path defined by the upstream side heat radiation fin is substantially matched. A space in which the flow path is formed is defined as a flow path formation space, a cross section perpendicular to the flow line of the refrigerant fluid in the flow path formation space is defined as a flow path cross section, and the other surface of the flow path cross section and this When the area surrounded by the reference plane offset from the predetermined part of the surface is the flow path cross-sectional area,
The other surface includes a first region surface provided on the upstream side of the refrigerant fluid, and a flow path cut-off smaller than a channel cross-sectional area provided on the downstream side of the refrigerant fluid and formed by the first region surface. The heat sink according to claim 1, further comprising a second region surface that forms an area.   The tip portions of the plurality of heat dissipating fins have a shape extending from a fixed end with respect to the other surface to a free end so as to incline in a downstream direction of the refrigerant fluid. The heat sink according to claim 1 or 2.

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