WO2020174593A1

WO2020174593A1 - Cooling device

Info

Publication number: WO2020174593A1
Application number: PCT/JP2019/007389
Authority: WO
Inventors: 伴明高木; 賢二安東
Original assignee: 住友精密工業株式会社
Priority date: 2019-02-26
Filing date: 2019-02-26
Publication date: 2020-09-03
Also published as: JP7119200B2; JPWO2020174593A1

Abstract

A coolant flow path (2) of this cooling device (100) includes an inlet opening (22) for inflow of the refrigerant (5), distribution paths (23) branching from the inlet opening and connecting to each heat exchange unit (21), and an outlet opening (24) for outflow of at least partially gasified refrigerant. Between the branching (23a) of the distribution paths and the heat exchange units, a resistance body (30) is provided which, by increasing the flow path resistance, suppresses fluctuation in the distribution amount of the refrigerant accompanying fluctuation of the heat generation amount of a heat generating body (M).

Description

Cooling system

The present invention relates to a cooling device, and more particularly to a cooling device that cools a heating element arranged on the surface by a refrigerant flowing through an internal refrigerant flow path.

Conventionally, a cooling device that cools a heating element by a refrigerant flowing through an internal refrigerant passage has been known. Such a cooling device is disclosed in, for example, Japanese Utility Model Laid-Open No. 63-145395.

In Japanese Utility Model Laid-Open No. 63-145395, a refrigerant flow of an electronic device in which a plurality of modules and a refrigerant supply device are mounted in an electronic device, and the refrigerant is circulated and supplied from the refrigerant supply device to each module through a flow path. A road conditioning structure is disclosed. In Japanese Utility Model Application Laid-Open No. 63-145395, a supply side flow path resistance adjuster is provided on each of the refrigerant supply sides and a discharge side flow path resistance adjuster is provided on each of the discharge sides of the refrigerant flow path of the module. The supply-side flow path resistance adjuster and the discharge-side flow path resistance adjuster are valves and the like.

In Japanese Utility Model Publication No. 63-145395, there is no specific explanation about the module.

Japanese Utility Model Publication No. 63-145395

A cooling device called a cold plate is used to cool a heating element such as an electronic device, which is not disclosed in Japanese Utility Model Laid-Open No. 63-145395. The cold plate cools the heating element installed on the surface by the refrigerant flowing through the internal flow path. Multiple heat generating elements may be installed on the cold plate. In this case, the flow path of the refrigerant should be branched in the cold plate and installed in parallel so as to pass directly under each heat generating element. There is.

Although not disclosed in Japanese Utility Model Laid-Open No. 63-145395, in such a cooling device, the cooling performance is improved by vaporizing the liquid phase refrigerant in the refrigerant channel and utilizing the heat of vaporization. Sometimes.

Here, the load (heat load, that is, the calorific value) of a heating element such as an electronic device installed on the cold plate fluctuates according to the operation of the electronic device. Therefore, in each heating element installed on the cold plate, The load fluctuates and is not uniform. At this time, in the refrigerant flow path branched inside the cold plate, the gas ratio of the refrigerant (ratio of vapor-phase refrigerant) increases on the high load side and the pressure loss increases due to volume change, while on the low load side. In this case, the gas rate remains low and the pressure loss becomes relatively low. As a result, in the branched refrigerant flow path, the refrigerant flow rate to the high load side is relatively reduced, and the refrigerant flow rate to the low load side is relatively increased, resulting in insufficient cooling performance on the high load side, There is a problem that the cooling performance of the entire device is reduced.

Therefore, in a cooling device that cools a plurality of heating elements by utilizing the heat of vaporization of the refrigerant in the branched flow path, it is required to suppress the fluctuation of the refrigerant distribution amount even when the load of the heating elements changes.

The present invention has been made to solve the above problems, and one object of the present invention is to cool a plurality of heating elements by utilizing heat of vaporization of a refrigerant in a branched flow path. In a cooling device, it is an object of the present invention to provide a cooling device capable of suppressing the variation of the refrigerant distribution amount even when the load of the heating element varies.

In order to achieve the above object, a cooling device according to the present invention includes a main body having an installation surface on which a heating element is installed, and a plurality of heating elements and a coolant provided on the installation surface between the plurality of heating elements and the refrigerant, respectively. A refrigerant flow path including a plurality of heat exchange sections that perform heat exchange is provided, and the refrigerant flow path is connected to the inlet opening into which at least a part of the liquid-phase refrigerant flows and a branch from the inlet opening, each of which is connected to the heat exchange section. A heating element is provided by including a distribution path and an outlet opening through which at least a part of the vaporized refrigerant flows out in the heat exchange section, and increasing flow path resistance between the branch section of the distribution path and the heat exchange section. A resistor that suppresses the variation in the distribution amount of the refrigerant due to the variation in the heat generation amount is provided.

In the cooling device according to the present invention, by configuring as described above, the flow of the refrigerant before the gas ratio is increased by the resistor at the position before the heat exchange part where the refrigerant is vaporized and between the branch part. The road resistance can be increased in advance. That is, when the load of the heat generating element in each heat exchange section of the branched refrigerant flow path changes, the pressure loss in each heat exchange section varies depending on the load change (difference in gas rate). At this time, when the resistor is not provided, the refrigerant distribution amount to each heat exchange section depends directly on the difference in pressure loss in each heat exchange section. Therefore, by increasing the pressure loss in advance with a resistor provided in front of each heat exchange unit, the pressure loss due to the resistor causes the difference in pressure loss in each heat exchange unit to be the refrigerant distribution amount to each heat exchange unit. Can be relatively small. As an extreme example for explanation, if the increase in the pressure loss due to the resistor is sufficiently large with respect to the amount of change in the pressure loss due to the fluctuation of the gas rate in each heat exchange part, the gas in each heat exchange part The difference in pressure loss due to the difference in rate becomes almost negligible. For this reason, according to the above configuration, in the cooling device that cools the plurality of heating elements by utilizing the heat of vaporization of the refrigerant in the branched flow path, the refrigerant distribution amount even when the load of the heating elements changes. Can be suppressed.

In the above-mentioned invention, preferably, the refrigerant flow passage includes a discharge passage that joins from the respective heat exchange portions and is connected to the outlet opening, and the resistor is provided not in the discharge passage but in the distribution passage. Here, if a resistor is provided in the discharge passage on the downstream side after a difference in pressure loss occurs due to a difference in gas ratio in each heat exchange section, it acts in a direction to expand the difference in pressure loss in each heat exchange section. Resulting in. Therefore, according to the above configuration, since the resistor is arranged only on the upstream side (distribution path) before the difference in the gas ratio in each heat exchange section occurs, it is possible to effectively suppress the variation in the refrigerant distribution amount. it can.

In the above invention, preferably, the resistor is arranged in the distribution path at a position separated from the heat exchange section so as not to be affected by heat conduction from the heat exchange section due to heat exchange with the heating element. Here, even before the heat exchange section, at a position in the vicinity of the heat exchange section, the heat of the heating element may be transferred by heat conduction and the refrigerant may be vaporized. If the resistor is provided after the difference in the gas ratio occurs, the difference in pressure loss between the heat exchange sections will be increased. Therefore, according to the above configuration, it is possible to suppress vaporization of the refrigerant due to the effect of heat conduction from the heat exchange section at the arrangement position of the resistor. Therefore, the flow path resistance (pressure loss) can be increased at the position in the previous stage where the heat of the heat generating element affects.

In this case, the resistor is preferably arranged at a position closer to the branch portion than the heat exchange portion in the distribution path. According to this structure, the resistor is arranged at a position relatively distant from the heat exchange section, so that the heat of the heating element more reliably causes a difference in the gas rate (pressure loss due to vaporization). The flow path resistance (pressure loss) can be increased at the position.

In the above invention, preferably, the plurality of heat exchange sections include a first heat exchange section and a second heat exchange section, and the resistor has a pressure loss in one of the first heat exchange section and the second heat exchange section. When the pressure loss in the other of the first heat exchange unit and the second heat exchange unit is minimum, the flow rate difference of the refrigerant distributed to each of the first heat exchange unit and the second heat exchange unit is preset. The flow path resistance of the coolant flow path at the installation position is increased so that the flow path resistance falls within the specified range. According to this structure, the distribution amount of the refrigerant is kept within the preset range even when the loads of the first heat exchange unit and the second heat exchange unit are maximally different from each other and the pressure loss is maximal. be able to. Therefore, it is possible to ensure the performance of the cooling device that can cope with the case where the load of the heating element fluctuates to the maximum.

In the above invention, preferably, the heat exchange section includes a first fin provided along the circulation direction of the refrigerant, and the resistor is configured to increase the flow path resistance more than the first fin under the same condition. Has been done. Here, the same condition is a condition assuming a case in which the first fin and the resistor are provided at the same position in the refrigerant flow path with the same dimensions. Under this same condition, the flow resistance of each of the first fin and the resistor is determined by its structure, and the resistor has a structure that increases the flow resistance more than that of the first fin. According to this structure, unlike the case where the flow path resistance is increased by providing the first fin also in the distribution path, for example, the flow path resistance can be effectively increased by the resistor. The length of the resistor can be suppressed. As a result, it is possible to prevent the flow path length of the coolant flow path from unnecessarily increasing, and thus it is possible to prevent the cooling device from increasing in size due to the increase in the flow path length.

In the above invention, preferably, the resistor is provided with a second fin that is provided in a direction intersecting with the circulation direction of the refrigerant and that allows the coolant to pass in the circulation direction. Here, usually, the fins for heat transfer provided in the heat exchange portion are provided so as to extend along the circulation direction of the refrigerant, and the heat transfer area is locally divided into a plurality of channels to divide the heat transfer area. To improve heat exchange performance. On the other hand, according to the above configuration, the flow passage resistance is effectively increased by the second fins that are directed in the direction intersecting the flow direction of the coolant (the direction different from the normal direction) so as to block the coolant while allowing the coolant to pass therethrough. Can be increased to Further, since the fins are members that are also provided in the heat exchange section, there is no need to provide a dedicated member as a resistor, and the device configuration can be simplified.

In this case, preferably, the second fin forming the resistor includes an offset fin or a perforate fin. Here, the offset fin is a fin formed so that a plurality of fin portions extending in a predetermined direction so as to partition the refrigerant flow path are displaced in the width direction orthogonal to the predetermined direction, and the gaps in which the respective fin portions are displaced Refrigerant can be distributed in a part. The perforated fin is a fin having a through hole in the fin portion, and the refrigerant can flow through the through hole. Since the gap between the offset fins and the through hole of the perforate fin can be made sufficiently small, by using these fins as the second fin, it is possible to effectively increase the flow path resistance even in a short distance. A resistor can be formed. Further, there are various types of offset fins in the amount of displacement in the width direction and the length of the fin portion, and since there are various types of perforate fins in the size and number of through holes, these are used. This makes it possible to easily obtain a resistor having a flow path resistance suitable for the coolant flow path.

When the resistor is composed of the second fins, preferably, the main body includes a wall that defines the refrigerant flow path, a plate member that constitutes the installation surface, and a resistor arranged in the refrigerant flow path. Has a structure integrated by brazing. According to this structure, the coolant flow path and the resistor can be reliably joined together by brazing. On the other hand, in brazing, the brazing filler metal is melted to join the members together. It is necessary to prevent clogging, which increases the manufacturing difficulty. On the other hand, in the resistor formed by the second fins, there is a track record that many fins for heat transfer are used in the cooling device joined by brazing, and the fins are joined together without causing clogging. It's easy to do. Therefore, in the resistor configured by the second fin, even when performing collective joining by brazing, it is possible to easily configure the resistor without causing clogging and deviation from the design value of the flow path resistance. Both the performance of the cooling device and the ease of manufacturing can be achieved.

In a cooling device that cools a plurality of heating elements using the heat of vaporization of the refrigerant in the branched flow path, it is possible to suppress fluctuations in the refrigerant distribution amount even when the load on the heating elements changes.

It is a typical perspective view showing the state where a heating element was installed in a cooling device by this embodiment. It is a typical horizontal sectional view showing a refrigerant channel inside a main part. It is the figure which expanded and showed the distribution path of the refrigerant flow path of FIG. It is a perspective view showing an example of a plane fin. It is a perspective view showing an example of a perforate fin. It is a perspective view showing an example of an offset fin. It is a figure for explaining a fluid circuit which circulates a refrigerant in a cooling device. It is a figure for demonstrating the refrigerant|coolant distribution amount when there is no load change of a heat generating body in the comparative example which does not provide a resistor. It is a figure for demonstrating the refrigerant|coolant distribution amount when there is a load change of a heat generating body in the comparative example which does not provide a resistor. It is a figure for demonstrating the refrigerant|coolant distribution amount in case the load of a heating element changes in the cooling device of this embodiment. It is the schematic diagram which showed the curved connection path by a modification. It is a schematic diagram which showed the modification which provided the drift suppression part in the distribution path.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

The configuration of the cooling device 100 according to the embodiment will be described with reference to FIGS. 1 to 7. The cooling device 100 is a liquid-cooled cold plate that absorbs heat from a heating element installed on the upper surface (installation surface) and cools it. The heating element M is not particularly limited, but is a heating element such as various electronic devices, electronic circuits (or elements forming the electronic circuits), or the like. The heating element M may be, for example, a power module mounted in a power conversion device, or a processor such as a CPU (Central Processing Unit) or GPU (Graphics Processing Unit) mounted in a computer. In the following, an example in which the heating element M is a power module including a power control switching element such as an IGBT (insulated gate bipolar transistor) will be described.

(Main body)
As shown in FIG. 1, the cooling device 100 includes a main body 1. The main body 1 has an installation surface 11 on which the heating element M is installed. The main body 1 has a coolant passage 2 (see FIG. 2) therein, through which a coolant 5 for cooling the heating element M installed on the installation surface 11 flows.

The main body 1 has an approximately rectangular flat plate shape. The main body 1 has a flat surface-shaped first surface (upper surface) and a second surface (lower surface), respectively. A nozzle that serves as a connection port for the refrigerant flow passage 2 to an external refrigerant flow passage (such as a pipe) is provided on one side end surface of the main body 1 in the longitudinal direction (X1 direction) and the other side end surface thereof (X2 direction). 3 are provided. Each nozzle 3 has an opening for the refrigerant 5 to enter and exit. The two nozzles 3 are in communication with an inlet opening 22 and an outlet opening 24, which will be described later, of the refrigerant channel 2 through the openings. Hereinafter, for convenience, of the two directions orthogonal to each other in plan view (top view), the longitudinal direction of the main body 1 is the X direction, and the lateral direction of the main body 1 is the Y direction. The thickness direction (vertical direction) of the main body 1 is defined as the Z direction.

In the example of FIG. 1, the first surface (upper surface) of the main body 1 is the installation surface 11. The installation surface 11 is, for example, a flat surface, but unevenness may be formed according to the shape of the heating element M. A plurality of placement areas 12 for placing the heating elements M are formed on the installation surface 11. The arrangement area 12 is an area in the installation surface 11 where the heating element M is placed and the surface of the heating element M and the installation surface 11 are in contact with each other. In the example of FIG. 1, the main body 1 is provided with four placement regions 12, and four cooling elements 100 can be placed in the cooling device 100.

In the example of FIG. 1, the heating element M, which is a power module, has a rectangular plate shape in plan view. Each of the placement regions 12 is formed such that the heating element M is placed with its long side aligned with the X direction and its short side aligned with the Y direction. The planar shape of the heating element M is arbitrary.

The main body 1 is provided with screw holes (not shown) corresponding to the respective placement areas 12, and the heating element M can be positioned and fixed in the placement area 12. The heating element M is placed (installed) so as to be in close contact with the placement area 12 on the installation surface 11 in a state where the gap is eliminated by a heat conductive compound or heat dissipation grease.

The main body 1 has a structure in which a wall 13 that defines the internal coolant flow passage 2 and a plate member 14 that constitutes upper and lower surfaces (first surface and second surface) in the thickness direction are joined. The installation surface 11 is composed of the outer surfaces of the upper and lower plate members 14.

(Refrigerant flow path)
As shown in FIG. 2, the coolant channel 2 is a coolant circulation space formed inside the main body 1. The coolant channel 2 is partitioned by the wall portion 13 and the plate member 14 (see FIG. 1). The coolant channel 2 is a passage through which the coolant 5 flows. The coolant flow channel 2 includes a plurality of heat exchange portions 21 formed at a position immediately below the arrangement region 12 (that is, a position overlapping the arrangement region 12 in plan view). The refrigerant flow path 2 of the present embodiment is configured such that at least a part of the liquid-phase refrigerant 5 flows in a saturated state, a part of which is vaporized in the heat exchange section 21, and the gas-liquid mixed-phase refrigerant 5 flows out. Has been done. That is, the cooling device 100 cools the heating element M using the heat of vaporization accompanying the phase change (vaporization) of the refrigerant 5. As such a refrigerant 5, for example, a refrigerant of a fluorine-based organic compound such as HFC (hydrofluorocarbon) or HFO (hydrofluoroolefin) can be used.

The refrigerant channel 2 is configured to include a channel that supplies the refrigerant 5 to each heat exchange section 21 and a channel that discharges the refrigerant from each heat exchange section 21. That is, the refrigerant flow path 2 includes an inlet opening 22, a distribution path 23 branched from the inlet opening 22 and connected to the heat exchange unit 21, and an outlet opening 24. Further, the refrigerant flow path 2 includes a discharge passage 25 that joins the heat exchange portions 21 and is connected to the outlet opening 24. The refrigerant 5 flows from the inlet opening 22 toward the outlet opening 24. Regarding the circulation direction of the refrigerant 5 in the refrigerant flow path 2, the direction toward the inlet opening 22 is called the upstream side, and the direction toward the outlet opening 24 is called the downstream side.

The inlet opening 22 is an end opening of the coolant channel 2, and one is provided on the side end surface of the main body 1. In the example of FIG. 2, the inlet opening 22 opens at the side end surface of the main body 1 on the X1 direction side and communicates with the nozzle 3 on the X1 direction side. The inlet opening 22 receives the refrigerant 5 from the outside and supplies it into the refrigerant flow path 2. At least a part of the liquid-phase refrigerant 5 flows into the inlet opening 22. The refrigerant 5 may flow into the inlet opening 22 in a substantially liquid phase (gas ratio=0%) state, or may partially flow into the inlet opening 22 in a gas-liquid mixed phase state. Good. At the inlet opening 22, the refrigerant 5 has a larger liquid phase ratio than the gas phase.

The distribution passage 23 is a branched passage portion of the refrigerant passage 2 that has one end on the upstream side and a plurality of ends on the downstream side. The upstream end of the distribution path 23 communicates with the inlet opening 22. The plurality of downstream end portions of the distribution passage 23 are in communication with the heat exchange portion 21, respectively. The distribution path 23 is configured to distribute the refrigerant 5 from the inlet opening 22 to the plurality of heat exchange units 21. The number of the plurality of downstream end portions of the distribution path 23 is two in the example of FIG. As shown in FIG. 3, the distribution path 23 is branched from one inlet opening 22 at a branch portion 23a and is connected to each of the two heat exchange portions 21 on the downstream side. In the following, each downstream flow path portion that is divided from the branch portion 23a is referred to as a tributary flow path 26.

In the example of FIG. 2 and FIG. 3, the distribution passage 23 extends in the X2 direction from the inlet opening 22 to the branch portion 23a, and is branched into two on both sides in the Y direction at the branch portion 23a, and then each tributary flow path 26 is in the X2 direction. To each of the two heat exchange parts 21 arranged in the Y direction. The tributary channels 26 after the branch portion 23a do not communicate with each other. The total flow rate of the refrigerant in each tributary channel 26 corresponds to the flow rate flowing into the inlet opening 22.

In the present embodiment, the flow path resistance is increased between the branch portion 23a of the distribution path 23 and the heat exchange portion 21 (the tributary flow path 26) so that the heat generation amount (load) of the heating element M varies. A resistor 30 that suppresses fluctuations in the distribution amount of the refrigerant 5 is provided. The resistor 30 is an obstacle provided so as to block a part of the flow path between the branch portion 23 a of the distribution path 23 and the heat exchange portion 21. In the present embodiment, the resistor 30 is provided in the distribution passage 23 instead of being provided in the discharge passage 25. Details of the resistor 30 will be described later.

As shown in FIG. 2, the heat exchange part 21 is a part of the refrigerant flow path 2 and is a flow path part for performing heat exchange between the plurality of heating elements M on the installation surface 11 and the refrigerant 5, respectively. is there. In the example of the present embodiment, since the four heat generating elements M are installed in the four disposition regions 12, respectively, the heat exchange portions 21 are provided one at a position directly below the four disposition regions 12. The heat exchange part 21 is a flow path part having one end on the upstream side and one end on the downstream side.

The plurality of heat exchange parts 21 include a first heat exchange part 21a and a second heat exchange part 21b. The first heat exchange section 21a and the second heat exchange section 21b are connected in parallel to the inlet opening 22 by a branched distribution path 23. In the example of FIG. 2, the first heat exchange section 21a and the second heat exchange section 21b are arranged side by side in the Y direction with the wall 13a interposed therebetween. The first heat exchanging portion 21a and the second heat exchanging portion 21b are provided two by two in correspondence with the four heating elements M (arrangement region 12). That is, the two first heat exchange portions 21a arranged in the X direction form one set, and are connected in series in the X direction in the refrigerant passage 2. The two second heat exchanging portions 21b arranged in the X direction form one set, and are connected in series in the X direction in the refrigerant passage 2. The rows of the first heat exchange portions 21a and the rows of the second heat exchange portions 21b extending in the X direction are arranged in parallel in the Y direction.

With respect to the pair of first heat exchange parts 21a (second heat exchange part 21b) arranged in the X direction, the refrigerant 5 is first provided in the first heat exchange part 21a (second heat exchange part 21b) on the upstream side. Supplied. The refrigerant 5 that has passed through the upstream first heat exchange section 21a (second heat exchange section 21b) is supplied to the downstream first heat exchange section 21a (second heat exchange section 21b). The two first heat exchange portions 21a (second heat exchange portions 21b) arranged in the X direction are connected by a linear connection path 27. The two first heat exchanging parts 21a and the two second heat exchanging parts 21b arranged in the Y direction are partitioned by the wall part 13a that partitions the branched refrigerant flow path 2 and do not communicate with each other. ..

The individual heat exchange parts 21, which are the first heat exchange part 21a or the second heat exchange part 21b, extend linearly in the X direction. The flow path length (length in the flow direction of the refrigerant) and flow path width (length in the width direction orthogonal to the flow direction) of the heat exchange section 21 are the planar shape (arrangement region) of the heating element M (see FIG. 1). 12 shapes). The refrigerant 5 absorbs heat from each heating element M in the process of passing through the heat exchange section 21. Due to the heat absorption, part of the refrigerant 5 passing through the heat exchange section 21 is vaporized. The heat of vaporization of the refrigerant 5 can increase the heat exchange efficiency of the heating element M by the cooling device 100 as compared with the case where the heat of vaporization is not used.

Each heat exchange section 21 includes a first fin 21c provided along the circulation direction of the refrigerant 5. The first fin 21c is a heat transfer fin provided in the heat exchange unit 21. The first fin 21c increases the heat transfer area by locally dividing the refrigerant flow path 2 (heat exchange section 21) into a plurality of channels to improve heat exchange performance. The first fin 21c is, for example, a corrugated fin, and a plurality of plate-shaped fin portions 41 extending in the first direction in the plane are arranged at intervals in the second direction orthogonal to the first direction in the plane. Thus, the structure is provided. The first fin 21c is a fin provided such that the first direction in which the fin portion 41 extends is along the circulation direction (X direction) of the refrigerant 5 in the heat exchange portion 21.

As the type (fin shape) of the first fin 21c, for example, the plane fin 40a shown in FIG. 4, the perforate fin 40b shown in FIG. 5, the offset fin (also called serrate fin) 40c shown in FIG. You can The plane fin 40a has a structure in which fin portions 41 that linearly extend in the first direction (A direction) are arranged at a constant pitch P in the second direction (B direction). Each of the plurality of fin portions 41 is connected at one end in the height direction (vertical direction) with a plate-shaped connecting portion 45. The perforated fin 40b has a structure in which a plurality of through holes 42 are provided in the plain fin 40a. In the offset fin 40c, a plurality of rows 43 configured by arranging fin portions 41 extending in the first direction (direction A) in the second direction (direction B) are displaced from each other in the second direction (direction B) (offset). It is a fin provided as follows. The first fin 21c locally divides the refrigerant flow path (heat exchange portion 21) into a plurality of channels by the plurality of fin portions 41, thereby increasing the heat transfer area of the refrigerant 5.

Returning to FIG. 2, the discharge passage 25 is a flow passage portion that has a plurality of upstream end portions and one downstream end portion and joins the branched flow passages. The plurality of upstream end portions of the discharge passage 25 are in communication with the heat exchange portion 21, respectively. The downstream end of the discharge passage 25 communicates with the outlet opening 24. The discharge path 25 is configured to merge the refrigerant 5 that has passed through the branched heat exchange portions 21 and send the combined refrigerant 5 to the outlet opening 24. The number of the plurality of upstream end portions of the discharge passage 25 is two in the example of FIG.

The outlet opening 24 is an end opening of the refrigerant flow path 2 and one is provided on the side end surface of the main body 1. In the example of FIG. 2, the outlet opening 24 opens at the side end surface of the main body 1 on the X2 direction side and communicates with the nozzle 3 on the X2 direction side. The outlet opening 24 is provided on the most downstream side of the refrigerant flow path 2 and discharges the refrigerant 5 after heat exchange (after cooling) to the outside. From the outlet opening 24, the refrigerant 5 at least a part of which is vaporized in the heat exchange section 21 flows out. That is, a part of the liquid-phase refrigerant 5 flowing into the inlet opening 22 is vaporized to become the vapor-phase refrigerant 5, and the gas-liquid mixed-phase refrigerant 5 having a higher gas ratio than that at the time of flowing into the inlet opening 22 is generated. , Exits through the outlet opening 24. It should be noted that all of the liquid-phase refrigerant 5 that has flowed into the inlet opening 22 may be vaporized, and in that case, the gas-phase refrigerant 5 flows out from the outlet opening 24.

With such a configuration, the refrigerant flow path 2 includes two

paths

20a and 20b branched between the inlet opening 22 and the outlet opening 24. The passage 20a extends from the branch portion 23a of the refrigerant passage 2 and includes the tributary passage 26, the upstream first heat exchange portion 21a, the connection passage 27, and the downstream first heat exchange portion 21a. It is a route that passes through the exchange unit 21a. The passage 20b extends from the branch portion 23a of the refrigerant passage 2 and includes the tributary passage 26, the upstream second heat exchange portion 21b, the connection passage 27, and the downstream second heat exchange portion 21b. It is a route that passes through the exchange unit 21b.

The route 20a passing through the first heat exchange unit 21a and the route 20b passing through the second heat exchange unit 21b are the routes 20a when the loads (heat amounts) in the first heat exchange unit 21a and the second heat exchange unit 21b are equal to each other. The overall pressure loss and the overall pressure loss of the path 20b are configured to substantially match. Therefore, in the example shown in FIG. 2, the two

paths

20a and 20b from the branch portion 23a to the discharge path 25 have the same structure, and are substantially symmetrical in the Y direction with the branch portion 23a as a boundary.

(Resistor)
Next, details of the resistor 30 will be described. The resistor 30 is provided in at least one of the plurality of branch passages 26 between the branch portion 23 a of the distribution passage 23 and the heat exchange portion 21. In the example shown in FIG. 3, the resistor 30 is provided in each of the plurality (two) of the tributary channels 26. The resistor 30 is installed inside the coolant channel 2. The resistor 30 is fixed to the wall portion 13 and/or the plate member 14 that divides the coolant channel 2 in the coolant channel 2. The resistor 30 does not have a movable part for changing the opening degree of the valve body or the like, and causes a flow path resistance by a fixed structure.

The resistor 30 is arranged in the distribution path 23 at a position separated from the heat exchange part 21 so as not to be affected by heat conduction from the heat exchange part 21 due to heat exchange with the heating element M. Specifically, the resistor 30 is arranged in the distribution path 23 at a position closer to the branch portion 23a than the heat exchange portion 21. In the present embodiment, the resistor 30 is arranged immediately after the branch portion 23a. That is, the resistor 30 is provided at the position of the upstream end portion of the tributary channel 26 (the boundary portion between the branch portion 23a and the tributary channel 26). The downstream end of the resistor 30 is arranged upstream of the heat exchange part 21. In other words, the tributary flow path 26 includes a flow path portion that connects the downstream end of the resistor 30 and the heat exchange section 21. The resistor 30 has a width W1 that is substantially equal to the flow channel width of the tributary channel 26. The length L1 of the resistor 30 in the flow direction (X direction) of the refrigerant 5 is smaller than the length of the tributary flow path 26. In the flow direction (X direction) of the refrigerant 5, the length L1 of the resistor 30 is smaller than the length of the heat exchange section 21.

The resistor 30 increases the channel resistance of the refrigerant channel 2 as compared with the case where the resistor 30 is not installed. The resistor 30 may be configured by, for example, an orifice plate having fine holes, a block body provided so as to block a part of the tributary channel 26, or the like. In the present embodiment, the resistor 30 is configured to increase the flow path resistance more than that of the first fin 21c under the same condition. That is, the flow path resistance is increased as compared with the case where the first fin 21c is installed in place of the resistor 30 in the installation region of the resistor 30 shown in FIG.

As a specific example of the resistor 30, in the present embodiment, the resistor 30 includes a second fin 31 that is provided in a direction that intersects with the circulation direction of the coolant 5 and that allows the coolant 5 to pass in the circulation direction. Has been done. The second fins 31 circulate the coolant 5 in the normal installation direction (the first direction in which the fin portion 41 extends (direction A, see FIGS. 4 to 6)) for the purpose of increasing the flow path resistance (as the resistor 30 ). It is installed in the refrigerant flow path 2 in a direction different from the direction (toward the direction). The second fin 31 is, for example, a corrugated fin, which is a corrugated fin that allows the coolant 5 to flow in the circulation direction even if the second fin 31 is arranged in a direction intersecting with the circulation direction of the coolant 5.

The second fin 31 forming the resistor 30 includes an offset fin 40c (see FIG. 6) or a perforate fin 40b (see FIG. 5). In the present embodiment, the offset fin 40c is used as the second fin 31. The second fins 31 shown in FIG. 3 are installed with the first direction (A direction) in which the fin portions 41 extend toward the flow channel width direction (Y direction) orthogonal to the circulation direction (X direction) of the refrigerant 5. ing. Therefore, in the second fin 31, the fin portion 41 extending in the first direction (direction A) is configured to function as a barrier that blocks the refrigerant flow passage 2 (the tributary flow passage 26). In the second fins 31, the second direction (the B direction, see FIG. 6) that is the arrangement direction of the fin portions 41 matches the circulation direction (X direction) of the refrigerant 5.

The offset fin 40c (see FIG. 6) or the perforate fin 40b (see FIG. 5) as the second fin 31 is a fin that allows the refrigerant 5 to flow in the second direction (B direction). That is, in the offset fin 40c shown in FIG. 6, the position of the fin portion 41 is displaced in the second direction (B direction) between the odd-numbered row 43 and the even-numbered row 43 of the fin portion 41. Therefore, a gap 44 having a size corresponding to the offset amount Os in the B direction is formed between the fin portions 41 forming the even-numbered rows 43 and the fin portions 41 forming the odd-numbered rows 43. .. As a result, when the coolant 5 flows into the offset fins 40c in the second direction (direction B), the coolant 5 that collides with the side surfaces of the fin portions 41 enters the gaps 44 between the fin portions 41 and passes through the gaps 44. And zigzag between the fin portions 41. As a result, the refrigerant 5 can pass through the offset fin 40c in the second direction (direction B).

There are various types of offset fins 40c that differ in the length L2 of the fin portion 41, the pitch P of the fin portion 41 in each row 43, the offset amount Os of the fin portion 41, and the like. In the resistor 30 (second fin 31) configured by the offset fin 40c, the flow path resistance is determined by the length L2 of the fin portion 41, the pitch P of the fin portion 41, the offset amount Os of the fin portion 41, and the like. It becomes a parameter to do.

In the perforated fin 40b shown in FIG. 5, the through hole 42 formed in the fin portion 41 serves as a passage for the coolant 5 flowing in the second direction (B direction). Therefore, the refrigerant 5 can pass through the perforate fins 40b in the second direction (direction B). There are various types of perforated fins 40b that differ in the diameter (or opening area) of the through holes 42, the number of the through holes 42 (or the ratio of the through holes 42 to the non-through portions), the formation position of the through holes 42, and the like. is there. When the resistor 30 (second fin 31) is the perforate fin 40b, the diameter, number, position, etc. of these through holes 42 are parameters for increasing or decreasing the flow path resistance.

In this way, in the second fin 31 in which the refrigerant 5 flows in the B direction, a higher flow path resistance occurs as compared with the case where the refrigerant 5 flows in the A direction. Therefore, in the resistor 30 configured by the second fin 31, it is possible to reduce the distance required to obtain the desired flow path resistance. That is, as shown in FIG. 3, it is possible to reduce the length L1 of the resistor 30 required to realize a desired flow path resistance.

By the way, the main body portion 1 includes a wall portion 13 that divides the refrigerant flow passage 2, a plate member 14 (see FIG. 1) that constitutes the installation surface 11 (see FIG. 1 ), and a resistor arranged in the refrigerant flow passage 2. It has a structure in which the body 30 is integrated by brazing. That is, the wall portion 13, the first fin 21c, the resistor 30 (second fin 31), and the plate member 14 are all coated or coated with a brazing material, and as shown in FIG. , The first fin 21c and the resistor 30 (second fin 31) are arranged so that both sides in the thickness direction are sandwiched by the plate members 14, respectively, and the assembly is heated to a predetermined brazing temperature. By heating and melting the brazing filler metal, and then cooling the brazing filler metal, the members forming the main body 1 are joined together.

The flow path resistance by the resistor 30 is the amount of heat generated by the heating element M in the heat exchange section 21 on the downstream side of the resistor 30, the pressure loss of the entire refrigerant flow path 2, and the individual branch portions (from the branch section 23a). It is set in consideration of the pressure loss of the tributary flow path 26 to the confluence of the discharge path 25, the path including the heat exchange section 21, and the like.

When it can be considered that the amounts of heat generated by the heating elements M are equal, the flow resistances of the two resistors 30 installed on the

paths

20a and 20b are set to be substantially the same. On the other hand, when the performance of each heating element M is different and the amount of generated heat is different, the flow path resistances of the two resistors 30 may have different flow path resistances according to the respective heat quantities. In such a case, for example, the performance of each heating element M is different, and the amount of heat in each of the two first heat exchange units 21a is larger than the amount of heat in each of the two second heat exchange units 21b. To do.

Further, in the resistor 30, the pressure loss in one of the first heat exchange section 21a and the second heat exchange section 21b is maximum, and the pressure loss in the other of the first heat exchange section 21a and the second heat exchange section 21b is minimum. In this case, the flow path of the refrigerant flow path 2 at the installation position is set so that the difference in the flow rate of the refrigerant 5 distributed to each of the first heat exchange section 21a and the second heat exchange section 21b falls within a preset range. Increase resistance.

That is, the load (heat generation amount) of the heating element M, which is a power module, varies according to the operation of the power control switching element. This change in load is expressed here as a load factor. That is, the load of each heating element M fluctuates between a load rate of 0%, which is the designed minimum heat generation amount, and a load rate of 100%, which is the maximum heat generation amount. The gas rate in the heat exchange section 21 rises most when the load rate is 100%, and the rise rate is minimum (substantially zero rise rate) when the load rate is 0%. Therefore, one of the first heat exchanging portion 21a and the second heat exchanging portion 21b has a load factor of 100%, and the pressure loss due to the vaporization of the refrigerant 5 (increase of the gas rate) becomes maximum, and the first heat exchanging portion 21a In the case where the load factor of the other of the second heat exchange section 21b is 0% and the pressure loss due to the vaporization of the refrigerant 5 is minimum, the difference in the refrigerant distribution amount is maximum. In other words, the flow path resistance due to the resistor 30 is the first heat exchange when the difference in pressure loss due to vaporization of the refrigerant 5 between the first heat exchange section 21a and the second heat exchange section 21b is the maximum. The flow rate difference of the refrigerant 5 distributed to each of the exchange section 21a and the second heat exchange section 21b is set to fall within a preset range.

The range of the flow rate difference of the refrigerant 5 is preferably sufficiently small. For example, the range of the flow rate difference of the refrigerant 5 is 30% or less of the flow rate of the refrigerant at the inlet opening 22, and more preferably 20% or less.

(Fluid circuit)
The cooling device 100 of this embodiment constitutes a part of a fluid circuit 50 as shown in FIG. 7, for example. The fluid circuit 50 mainly includes a refrigerant circulating unit 51, a condensing unit 52, and a pipe line 53 connecting each unit. In addition, a valve (not shown) for adjusting the flow rate or the like may be provided in each part of the fluid circuit 50.

In the cooling device 100, the nozzle 3 on the inlet side is connected to the refrigerant circulation unit 51 via the pipe line 53. In the cooling device 100, the nozzle 3 on the outlet side is connected to the condensing unit 52 via the pipe line 53. The condenser section 52 is connected to the refrigerant circulation section 51 via the pipe line 53. The fluid circuit 50 is a closed fluid circuit that circulates the refrigerant 5 through the refrigerant circulation unit 51, the cooling device 100, and the condensation unit 52. The coolant circulation unit 51 includes a pump and supplies the coolant 5 to the cooling device 100. The refrigerant circulation unit 51 circulates the refrigerant 5 in the fluid circuit 50 by pressure. A plurality of cooling devices 100 may be provided in the fluid circuit 50, as indicated by the chain double-dashed line.

As shown in FIGS. 7 and 2, the coolant 5 supplied to the inlet opening 22 of the cooling device 100 passes through the branched distribution passage 23 through the first heat exchange section 21a and the second heat exchange section 21b, respectively. At this time, the heat of the heating element M (see FIG. 1) installed in the cooling device 100 is absorbed by the refrigerant 5, and a part of the refrigerant 5 is vaporized and the heating element M is cooled. The refrigerant 5 in the cooling device 100 merges in the discharge passage 25 and is discharged from the outlet opening 24. The refrigerant 5 discharged from the cooling device 100 is sent to the condenser 52. The condenser 52 returns the vaporized refrigerant 5 vaporized in the cooling device 100 to the liquid phase by discharging the heat absorbed by the refrigerant 5. The condensing part 52 can be configured by a known heat exchanger. The refrigerant 5 discharged from the condenser 52 returns to the refrigerant circulation unit 51 and circulates in the fluid circuit 50 again.

(Operation of cooling device)
Next, the operation of the cooling device 100 of this embodiment will be described. 8 and 9 are diagrams showing distribution amounts of the refrigerant 5 to the

paths

20a and 20b according to the comparative example in the case where the resistor 30 is not provided. FIG. 10 is a diagram showing the distribution amount of the refrigerant 5 to the

paths

20a and 20b according to the present embodiment in which the resistor 30 is provided. 8 to 10, for convenience of description, the refrigerant flow path 2 shown in FIG. 2 is simplified, and two first heat exchange sections 21a and two second heat exchange sections 21b are provided together. It is shown as one heat exchange section. It should be noted that the specific distribution amount (flow rate) and the value of the pressure loss shown in the following description are examples shown for the purpose of description, and are not limited to these.

FIG. 8 shows a comparative example (without a resistor) when the load of the heating element M in each of the first heat exchange section 21a and the second heat exchange section 21b is equal (load=100%). In this case, since the refrigerant flow path 2 is configured so that the pressure losses of the

paths

20a and 20b are equal, the refrigerant distribution amounts in the

paths

20a and 20b are the same in FIG. That is, when the flow rate at the inlet opening 22 is 20 L/min, the flow rate Q1 of the path 20a and the flow rate Q2 of the path 20b are Q1=Q2=10 L/min, respectively. The pressure loss ΔP of the entire refrigerant flow path 2 is ΔP=15 kPa. The pressure loss ΔP1 in the first heat exchange section 21a is equal to the pressure loss ΔP2 in the second heat exchange section 21b.

Next, FIG. 9 shows a comparative example (without a resistor) when the load of the heating element M in each of the first heat exchange section 21a and the second heat exchange section 21b is different. In FIG. 9, the heating element M has a load of 100% in the first heat exchange section 21a, and the heating element M has a load of 0% in the second heat exchange section 21b. In the first heat exchange unit 21a of the path 20a, the refrigerant 5 is vaporized by heat input from the heating element M (load 100%), and the pressure loss due to the vaporization of the refrigerant 5 (increase in gas rate) increases. On the other hand, in the second heat exchange section 21b of the path 20b, since the heat input from the heating element M is absent, the refrigerant 5 is not vaporized, and the increase in pressure loss unlike the first heat exchange section 21a does not occur. That is, at the same flow rate, the pressure loss ΔP2 in the second heat exchange section 21b is significantly smaller than the pressure loss ΔP1 in the first heat exchange section 21a.

As a result, when the load of the heating element M fluctuates between the route 20a and the route 20b as shown in FIG. 9, the inflow of the refrigerant 5 concentrates on the route 20b side, and the refrigerant distribution amount to the route 20a side decreases. As a result, the cooling capacity of the first heat exchange section 21a (load 100%) having a large amount of heat becomes insufficient. When the flow rate at the inlet opening 22 is 20 L/min, the flow rate Q1 is 2 L/min and the flow rate Q2 is 18 L/min in the

paths

20a and 20b, respectively. The pressure loss ΔP of the entire refrigerant passage 2 is ΔP=3 kPa.

Also in the present embodiment shown in FIG. 10, the load condition of the heating element M in each of the first heat exchange section 21a and the second heat exchange section 21b is the same as in FIG. That is, the heating element M has a load of 100% in the first heat exchange section 21a, and the heating element M has a load of 0% in the second heat exchange section 21b. In the

paths

20a and 20b, the resistors 30 have the same structure, but the pressure loss due to the respective resistors 30 reflects the difference in pressure loss (ΔP1, ΔP2) in the heat exchange section on the downstream side of each path. It becomes a value.

That is, in the path 20a, the pressure loss ΔP1 due to the vaporization of the refrigerant 5 is 12 kPa in the first heat exchange section 21a (load 100%). In the path 20b, the vaporization of the refrigerant 5 does not occur in the second heat exchange section 21b (load 0%), so that the pressure loss ΔP2=1 kPa. At this time, the pressure loss in the resistor 30 of the path 20a becomes 10 kPa, and the pressure loss in the resistor 30 of the path 20b becomes 21 kPa. As a result, even if the load of the heating element M is different, the pressure loss becomes equal in the path 20a and the path 20b, and the difference in the refrigerant distribution amount to the path 20a and the path 20b is suppressed. In the example of FIG. 10, when the flow rate at the inlet opening 22 is 20 L/min, the flow rate Q1=8.5 L/min and the flow rate Q2=11.5 L/min in the

paths

20a and 20b, respectively. The pressure loss ΔP of the entire refrigerant flow path 2 is ΔP=22 kPa.

As described above, in the present embodiment shown in FIG. 10, even when the load of the heating element M changes in the

paths

20a and 20b as in the comparative example shown in FIG. 9, the fluctuation of the refrigerant distribution amount is suppressed. To be done. In particular, in the comparative example shown in FIG. 9, the refrigerant flow rate Q1 to the first heat exchange section 21a with a load of 100% is 2 L/min, whereas in the present embodiment shown in FIG. 10, the refrigerant flow rate Q1 is Since it becomes 9.5 L/min, the shortage of the cooling capacity in the first heat exchanging portion 21a having a large heat quantity is alleviated. In the example of FIG. 10, the flow rate difference |Q1-Q2| of the refrigerant 5 distributed to each of the first heat exchange section 21a and the second heat exchange section 21b is 3 L/min, and the refrigerant flow rate at the inlet opening 22 ( It falls within 15% of 20 L/min). Although the description is omitted, even when the load of the first heat exchanging portion 21a and the load of the second heat exchanging portion 21b are reversed, the relationship between the flow rate Q1 and the flow rate Q2 is simply reversed and falls within the same range. .. In the actual design of the cooling device 100, the flow resistance of the resistor 30 is used as a variable parameter so that the difference between the flow rate Q1 and the flow rate Q2 in the case of FIG. 10 falls within a preset range. Road resistance is determined.

(Effect of this embodiment)
In this embodiment, the following effects can be obtained.

In the cooling device 100 according to the present embodiment, as described above, the refrigerant before the heat exchange section 21 where the refrigerant 5 is vaporized and the branch portion 23a is located before the gas ratio is increased by the resistor 30. The flow path resistance of No. 5 can be increased in advance. That is, by increasing the pressure loss in advance by the resistors 30 provided in front of each heat exchange section 21, as shown in FIG. 10, the pressure loss in each heat exchange section 21 is caused by the pressure loss by the resistors 30. The influence of the difference (ΔP1, ΔP2) on the refrigerant distribution amount (flow rate Q1, flow rate Q2) to each heat exchange section 21 can be made relatively small. As a result, in the cooling device 100 that cools the plurality of heating elements M by utilizing the heat of vaporization of the refrigerant 5 in the branched flow paths, the fluctuation of the refrigerant distribution amount is suppressed even when the load of the heating elements M changes. be able to.

Further, the resistor 30 is provided in the distribution passage 23 instead of being provided in the discharge passage 25, and is upstream before a difference in pressure loss (ΔP1, ΔP2) occurs due to a difference in gas ratio in each heat exchange portion 21. Since the resistor 30 is arranged only on the side (the distribution path 23), it is possible to effectively suppress the variation in the refrigerant distribution amount (flow rate Q1, flow rate Q2).

Further, the resistor 30 is arranged in the distribution path 23 at a position separated from the heat exchange part 21 so as not to be affected by heat conduction from the heat exchange part 21 due to heat exchange with the heating element M. The vaporization of the refrigerant 5 due to the heat conduction from the heat exchange portion 21 is suppressed at the arrangement position of the resistor 30. Therefore, the flow path resistance (pressure loss) can be increased at the position of the previous stage where the heat of the heating element M is affected.

Further, since the resistor 30 is arranged in the distribution path 23 at a position closer to the branch portion 23a than the heat exchange part 21, the resistor 30 can be arranged at a position relatively distant from the heat exchange part 21. As a result, the flow path resistance (pressure loss) to each heat exchange portion 21 can be increased more reliably at the position of the previous stage where the gas rate (pressure loss) differs due to the heat of the heating element M.

Further, when the pressure loss in one of the first heat exchange section 21a and the second heat exchange section 21b is maximum and the pressure loss in the other of the first heat exchange section 21a and the second heat exchange section 21b is minimum, To increase the flow passage resistance of the coolant flow passage 2 at the installation position so that the flow rate difference of the refrigerant 5 distributed to each of the first heat exchange portion 21a and the second heat exchange portion 21b falls within a preset range. In addition, since the resistor 30 is provided in the first heat exchanging portion 21a and the second heat exchanging portion 21b, even if the load is maximally different and the difference in pressure loss is maximal, the distribution amount of the refrigerant 5 is preset. It can fit within the set range. Therefore, it is possible to ensure the performance of the cooling device 100 that can cope with the case where the heat load of the heating element M changes to the maximum.

Further, since the resistor 30 is configured to increase the flow passage resistance more than the first fin 21c of the heat exchange section 21 under the same conditions, for example, by providing the first fin 21c in the distribution passage 23 as well. Unlike the case of increasing the channel resistance, the resistor 30 can effectively increase the channel resistance. Therefore, the length L1 of the resistor in the coolant flow direction (X direction) can be suppressed. As a result, it is possible to prevent the flow path length of the coolant flow path 2 from unnecessarily increasing, and thus it is possible to prevent the cooling device 100 from increasing in size due to the increase in the flow path length.

Further, the resistor 30 is provided in the direction (Y direction) intersecting the circulation direction of the refrigerant 5, and is constituted by the second fins 31 through which the refrigerant 5 can pass in the circulation direction. The second fins 31 directed in a direction (a direction different from the normal direction) intersecting the flow direction of the coolant 5 so as to block the coolant 5 can effectively increase the flow passage resistance while allowing the passage of the flow path. In addition, since the fin is a member that is also provided in the heat exchange section 21, it is not necessary to provide a dedicated member as the resistor 30, and the device configuration can be simplified.

Further, since the second fin 31 forming the resistor 30 includes the offset fin 40c, it is possible to form the resistor 30 capable of effectively increasing the flow path resistance even in a short distance. Further, as described above, since there are various types of the offset fin 40c in the offset amount Os and the length L2 of the fin portion 41, by using these, a resistor having a flow passage resistance suitable for the coolant flow passage 2 is provided. 30 can be easily obtained. As described above, even when the second fin 31 includes the perforate fin 40b, the same effect can be obtained.

In addition, in the main body portion 1, the wall portion 13 that defines the coolant flow passage 2, the plate member 14 that configures the installation surface 11, and the resistor 30 that is disposed in the coolant flow passage 2 are integrated by brazing. Since it has the above-mentioned structure, the coolant flow path 2 and the resistor 30 can be reliably joined together by brazing. On the other hand, in brazing, since the brazing material is melted and the members are joined together, for example, when the orifice plate with minute holes or the block body with minute gaps is used as the resistor 30, the molten brazing material is used. Therefore, it is necessary to prevent clogging, which increases the manufacturing difficulty. On the other hand, the resistor 30 including the second fin 31 has a large number of fins used in the cooling device joined by brazing, and thus the resistor 30 can be joined without causing clogging. It's easy. Therefore, in the resistor 30 including the second fins 31, the resistor 30 can be easily configured without causing clogging or deviation from the design value of the flow path resistance even when performing collective joining by brazing. Therefore, the performance of the cooling device 100 and the ease of manufacturing can be compatible.

(Modification)
It should be understood that the embodiments disclosed this time are exemplifications in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes meanings equivalent to the scope of claims for patent and all modifications (modifications) within the scope.

For example, in the above embodiment, an example in which the heating element M is a power module including a power control switching element has been shown, but the present invention is not limited to this. In the present invention, the heating element M is not particularly limited and may be any one.

Further, in the above embodiment, an example in which the four disposition regions 12 are provided on the installation surface 11 and the four heat exchange parts 21 are provided in the refrigerant flow path 2 has been shown, but the present invention is not limited to this. The number of the arrangement regions 12 (that is, the number of the heating elements M to be installed on the installation surface 11) may be two, three, or five or more as long as it is plural. The number of heat exchanging parts 21 may be provided according to the number of heating elements M installed on the installation surface 11.

Also, in the above embodiment, an example in which the first surface (upper surface) of the main body 1 is used as the installation surface 11 has been shown, but the present invention is not limited to this. The second surface (lower surface) of the main body 1 may be the installation surface 11, or both the first surface and the second surface may be the installation surface 11. When both the first surface and the second surface are the installation surfaces 11, the main body portion 1 is provided with the refrigerant channel 2 adjacent to the first surface and the refrigerant channel 2 adjacent to the second surface, A plurality of layers of the coolant channels 2 may be formed in the thickness direction of the main body 1.

Further, in the above embodiment, an example in which the inlet opening 22 is provided on the side end surface of the main body 1 in the X1 direction and the outlet opening 24 is provided on the side end surface of the main body 1 in the X2 direction has been shown, but the present invention is not limited to this. In the present invention, the inlet opening 22 and the outlet opening 24 may be provided on the same side end surface of the main body 1. In this case, the refrigerant flow path 2 extending from the inlet opening 22 may be turned back (U-turned) at the end opposite to the inlet opening 22 and connected to the outlet opening 24. Both the inlet opening 22 and the outlet opening 24 may be opened on any surface of the main body portion 1, for example, may penetrate the plate member 14 in the thickness direction and may be opened on the first surface or the second surface. ..

In the above embodiment, the plane fin 40a, the perforate fin 40b, or the offset fin 40c is shown as an example of the first fin 21c, but the present invention is not limited to this. In the present invention, a louver fin or a herringbone fin other than these may be adopted as the first fin 21c.

Further, in the above embodiment, an example in which the refrigerant flow path 2 is branched into two tributary flow paths 26 is shown, but the present invention is not limited to this. In the present invention, the refrigerant channel 2 may be branched into three or more. For example, with respect to the four heat exchange parts 21, the refrigerant flow path 2 may be branched into four branch flow paths 26. Further, instead of branching into four at one branching portion 23a, after branching into two at the first branching portion and then further branching into two at the second branching portion provided in each tributary flow path 26, a total of four branches are made. Such a configuration may be used.

Further, in the above embodiment, an example in which the resistor 30 is provided in each of the tributary flow paths 26 of the refrigerant flow path 2 branched into two has been shown, but the present invention is not limited to this. In the present invention, it is not necessary to provide the resistor 30 in all the branched tributary channels 26, and the resistor 30 may be provided only in a part of the branched tributary channels 26. For example, the heating element M of the first heat exchanging portion 21a and the heating element M of the second heat exchanging portion 21b have different operating rates of the power modules, and the heating element M of the first heat exchanging portion 21a always has a load of about 100%. On the other hand, when the heating element M of the second heat exchange section 21b operates at a load of around 30%, the resistor 30 is provided in the tributary flow path 26 on the second heat exchange section 21b side. You can just do it.

Further, in the above embodiment, the example in which the resistor 30 is provided in the distribution passage 23 and not in the discharge passage 25 is shown, but the present invention is not limited to this. A resistor may be provided in the discharge passage 25 as well. At this time, if the increment of the pressure loss due to the resistor provided in the discharge passage 25 is sufficiently smaller than the increment of the pressure loss due to the resistor 30 provided in the distribution passage 23, the refrigerant provided by the resistor provided in the discharge passage 25 is used. Since the influence of the variation of the distribution amount increases is sufficiently smaller than the effect of suppressing the variation of the refrigerant distribution amount by the resistor 30 provided in the distribution path 23, there is no problem.

Further, in the above-described embodiment, the example in which the resistor 30 is arranged in the distribution path 23 closer to the branch portion 23a than the heat exchange portion 21 is shown, but the present invention is not limited to this. The resistor 30 may be provided at least between the branch part 23a of the distribution path 23 and the heat exchange part 21, and the resistor 30 may be closer to the heat exchange part 21 than the branch part 23a. However, when the refrigerant 5 is vaporized by the heat of the heating element M at the installation position of the resistor 30, the pressure loss of the resistor 30 on the high load side relatively increases, and the pressure of the resistor 30 on the low load side increases. The loss is relatively reduced, and the effect of suppressing the variation in the refrigerant distribution amount due to the provision of the resistor 30 is reduced. Therefore, it is preferable to dispose the resistor 30 at a position distant from the heat exchange unit 21 at least to the extent that it is not affected by the heat of the heating element M.

In the above embodiment, the length L1 of the resistor 30 is smaller than the length of the heat exchange section 21 in the circulation direction (X direction) of the refrigerant 5, but the present invention is not limited to this. .. The length L1 of the resistor 30 in the circulation direction of the refrigerant 5 may be the same as the length of the heat exchange section 21, or may be larger than the length of the heat exchange section 21.

Further, in the above embodiment, the example in which the second fin 31 configuring the resistor 30 is the offset fin 40c has been described, but the second fin 31 may be the perforate fin 40b as described above.

Further, in the above-described embodiment, the example in which the resistor 30 is configured to increase the flow path resistance more than that of the first fin 21c under the same condition is shown, but the present invention is not limited to this. In the present invention, the flow resistance of the resistor 30 and the flow resistance of the first fin 21c may be about the same, or the flow resistance of the first fin 21c may be higher.

Further, in the above-described embodiment, an example in which the main body 1 has a structure in which the wall 13, the plate member 14, and the resistor 30 are integrated by brazing is shown, but the present invention is not limited to this. Absent. Each member of the main body 1 may be integrated by a method other than brazing (welding, fastening, solid phase diffusion bonding, etc.).

In addition, in the above-described embodiment, as shown in FIG. 2, the refrigerant flow path 2 has a shape in which it is branched into two and linearly extends in the X direction, and then merges, but the present invention is not limited to this. The shape of the coolant channel 2 (path in the main body 1) is arbitrary, and the position of the heating element M (arrangement region 12) on the installation surface 11, the positions of the inlet opening 22 and the outlet opening 24, the position of the main body 1 It may be appropriately set according to the outer shape and the like.

For example, in the example of FIG. 2, an example in which the two first heat exchanging portions 21a and the two second heat exchanging portions 21b are arranged in the X direction and connected by the linear connecting path 27 is shown. Each 1st heat exchange part 21a (each 2nd heat exchange part 21b) does not need to be located in a line with the X direction. Further, as shown in FIG. 11, for example, the connection path 27 that connects the upstream heat exchange portion 21 and the downstream heat exchange portion 21 may have a non-linear shape.

In FIG. 11, the connecting path 27 is bent with two bent portions 71. As shown in FIG. 11, when the refrigerant 5 that has passed through the heat exchange section 21 on the upstream side passes through the curved connecting path 27 and flows into the heat exchange section 21 on the downstream side, the refrigerant 5 becomes a gas-liquid mixed phase state. Therefore, due to the centrifugal force, the liquid-phase refrigerant 5 having a large specific gravity is concentrated on the outer peripheral side of the bent portion 71, and the gas-phase refrigerant 5 is concentrated on the inner peripheral side. If the gas phase and the liquid phase are separated in the connection path 27 and flow into the heat exchange section 21 on the downstream side in a biased state, the cooling capacity may decrease. Therefore, when the curved connecting path 27 is adopted, it is preferable to provide the drift suppressing portion 73 that divides the connecting path 27 into the plurality of channels 72 at the bent portion 71, as shown in FIG. 11. The uneven flow suppressing portion 73 is, for example, a fin extending along the circulation direction of the coolant 5, and is preferably configured by a plain fin 40a (see FIG. 4) or the like in which the coolant 5 does not flow in the second direction (B direction). .. As a result, in the bent portion 71, the bias between the gas phase and the liquid phase locally occurs in the channel 72 between the fin portions 41. Therefore, it is possible to suppress the deviation between the gas phase and the liquid phase as compared with the case where the deviation is generated in the entire connection passage 27 without providing the deviation suppressing portion 73.

Furthermore, when there is a straight line portion 74 in the curved connecting path 27 as shown in FIG. 11, the straight line portion 74 is a void portion in which no fins are provided, or the refrigerant 5 can also flow in the second direction (B direction). It is preferable to provide such a fin (that is, a perforate fin 40b (see FIG. 5) or an offset fin 40c (see FIG. 6)). As a result, the refrigerant 5 can flow in the straight line portion 74 in the flow channel width direction. As a result, it is possible to suppress uneven flow due to the difference in path length between the refrigerant 5 passing on the outer peripheral side and the refrigerant 5 passing on the inner peripheral side of the curved connection path 27.

The configuration in which the nonuniform flow suppressing portion 73 is provided in the bent portion 71 may be applied to the bent portion 75 of the distribution path 23 as shown in FIG. That is, when the refrigerant 5 in the gas-liquid mixed phase is supplied to the inlet opening 22, the nonuniform flow suppressing portion 73 may be provided in each bent portion 75 of the distribution passage 23. As a result, it is possible to prevent the refrigerant 5 that has previously flowed in the gas-liquid mixed phase from flowing unevenly in the distribution passage 23 between the gas phase on the inner peripheral side and the liquid phase on the outer peripheral side.

DESCRIPTION OF SYMBOLS 1 Main body part 2 Refrigerant flow path 5 Refrigerant 11

Installation surface

13, 13a Wall part 14 Plate member 21 Heat exchange part 21a 1st heat exchange part 21b 2nd heat exchange part 21c 1st fin 22 Entrance opening 23 Distribution path 23a Branch part 24 Outlet opening 25 Discharge path 30 Resistor 31 Second fin 40b Perforate fin 40c Offset fin 100 Cooling device M Heating element Q1 Flow rate Q2 Flow rate ΔP Pressure loss of refrigerant flow path ΔP1 Pressure loss of first heat exchange section ΔP2 Second heat Pressure loss in the exchange section

Claims

A main body having an installation surface on which a heating element is installed,
Provided in the main body portion, and comprising a refrigerant flow path including a plurality of heat exchange portions that perform heat exchange between the plurality of heating elements and the refrigerant on the installation surface,
The refrigerant passage has an inlet opening at least a portion of which a liquid-phase refrigerant flows into, a distribution passage branched from the inlet opening and connected to the heat exchange section, and at least a part of which is vaporized in the heat exchange section. An outlet opening through which the refrigerant flows,
A resistor is provided between the branch part of the distribution path and the heat exchange part to increase the flow path resistance to suppress the variation in the distribution amount of the refrigerant due to the variation in the heat generation amount of the heating element. The cooling system.
The refrigerant passage includes a discharge passage that merges from the respective heat exchange units and is connected to the outlet opening,
The cooling device according to claim 1, wherein the resistor is provided not in the discharge passage but in the distribution passage.
The resistor is arranged in the distribution path at a position separated from the heat exchange unit so as not to be affected by heat conduction from the heat exchange unit due to heat exchange with the heat generator. The cooling device according to 1.
The cooling device according to claim 3, wherein the resistor is arranged at a position closer to the branch portion than the heat exchange portion in the distribution path.
A plurality of the heat exchange units include a first heat exchange unit and a second heat exchange unit,
In the case where the resistor has a maximum pressure loss in one of the first heat exchange section and the second heat exchange section and a minimum pressure loss in the other of the first heat exchange section and the second heat exchange section. In addition, the flow path resistance of the refrigerant flow path at the installation position is increased so that the difference in flow rate of the refrigerant distributed to each of the first heat exchange section and the second heat exchange section falls within a preset range. The cooling device according to claim 1, wherein
The heat exchange section includes first fins provided along the flow direction of the refrigerant,
The cooling device according to claim 1, wherein the resistor is configured to increase the flow path resistance more than the first fin under the same condition.
The cooling device according to claim 1, wherein the resistor is provided with a second fin that is provided in a direction that intersects a flow direction of the refrigerant and that is configured to pass through the coolant in the flow direction.
The cooling device according to claim 7, wherein the second fins forming the resistor include an offset fin or a perforate fin.
The main body portion has a structure in which a wall portion that divides the refrigerant flow passage, a plate member that constitutes the installation surface, and the resistor arranged in the refrigerant flow passage are integrated by brazing. The cooling device according to claim 7.