Cooling apparatus and semiconductor apparatus with cooling apparatus

A cooling apparatus includes: a first member including a first surface in contact with a cooling target, a second surface opposite to the first surface, and radiating fins protruding from the second surface; and a second member including a third surface facing the second surface, a refrigerant flows between the first member and the second member, the second member includes a first protrusion protruding from the third surface toward a space, the space existing between the radiating fins in a flow direction of the refrigerant, the first protrusion includes a first slope inclined to the third surface, the first slope includes a first end and a second end, the first end is closer to the second surface than the second end, the second end is closer to the third surface than the first end, the first end is positioned downstream in the flow direction from the second end.

CROSS REFERENCE TO RELATED APPLICATION

This application is based on, and claims priority from, Japanese Patent Application No. 2021-085041, filed May 20, 2021, the entire content of which is incorporated herein by reference.

BACKGROUND

Technical Field

The disclosure relates to a cooling apparatus and to a semiconductor apparatus with the cooling apparatus.

Related Art

Japanese Patent Applications Laid-Open Publications Nos. 2008-172014 and 2011-108683 each disclose a cooling apparatus for causing a semiconductor to radiate heat to cool the semiconductor. The cooling apparatus is in contact with a semiconductor and a refrigerant flows through the cooling apparatus. There is known a technique for enhancing cooling performance of such a cooling apparatus. In the technique, such a cooling apparatus includes a plurality of protrusions protruding from a member in contact with a semiconductor toward a flow path of a refrigerant.

Japanese Patent Application Laid-Open Publication No. 2020-35998 discloses a cooler in which a plurality of cooling fins and a water jacket are not integrated with each other, that is, it is an open-type cooler. This cooler includes a refrigerant flowing path configured by a combination of a heat sink and a path component. This cooler includes a plurality of fins, each protruding from the heat sink toward the path component. The path component includes an inner wall surface with both a first portion and a second portion. The first portion faces the plurality of fins. The second portion is a portion into which a refrigerant enters from outside the refrigerant flowing path. The first portion includes a plurality of recesses. Each of the recesses includes a bottom surface that is farther from a cooling target than the second portion. Each of the fins includes a tip that is farther from the cooling target than the second portion. Each tip is in a space defined by a recess.

Therefore, the cooler disclosed in Japanese Patent Application Laid-Open Publication No. 2020-35998 prevents an increase in a flow rate of a refrigerant, which flows through a gap between the tip of each of the fins and the path component without sufficiently cooling the fins. An object of this cooler is to improve performance of cooling a cooling target by increasing a flow rate of a refrigerant that contributes to cooling the fins.

However, the technique disclosed in Japanese Patent Application Laid-Open Publication No. 2020-35998 causes a decrease in a flow rate of a refrigerant around the tip of each fin. Therefore, the technique causes a decrease in a flow rate of a refrigerant, which has passed through the gap between the tip of a fin and the path component, flowing toward a root of a fin. Consequently, even if there is a sufficient temperature difference between a cooling target and a refrigerant, the cooling target cannot radiate a sufficient amount of heat via the fins.

SUMMARY

An object of this disclosure is to provide a cooling apparatus capable of cooling a cooling target more efficiently than conventional apparatuses, and a semiconductor apparatus with the cooling apparatus.

In one aspect, a cooling apparatus includes: a first member including a first surface in contact with a cooling target, a second surface opposite to the first surface, and a plurality of radiating fins protruding from the second surface; and a second member including a third surface facing the second surface, a refrigerant flows between the first member and the second member, the second member includes a first protrusion protruding from the third surface toward a space, the space existing between the radiating fins in a flow direction of the refrigerant, the first protrusion includes a first slope inclined to the third surface, the first slope includes a first end and a second end, the first end is closer to the second surface than the second end, the second end is closer to the third surface than the first end, and the first end is positioned downstream in the flow direction from the second end.

In another aspect, a semiconductor apparatus includes the cooling apparatus described above.

DESCRIPTION OF THE EMBODIMENTS

Cooling apparatuses according to embodiments are described with reference to the drawings. In each drawing, dimensions and scales of elements may be different from those of actual products. The embodiments described below include various technical limitations. The scope of the disclosure is not limited to the embodiments described below.

1. First Embodiment

A cooling apparatus according to a first embodiment will be described below with reference toFIGS.1to8.

1.1 Configuration of First Embodiment

FIG.1is a diagram of both a cooling apparatus1according to a first embodiment and a semiconductor apparatus5including the cooling apparatus1. The cooling apparatus1includes a heat radiating plate10and a water jacket20. The heat radiating plate10is arranged on the water jacket20. The heat radiating plate10may be preferably made of metal, in particular, a metal with a relatively high heat transfer coefficient such as copper or aluminum. A way to arrange the heat radiating plate10on the water jacket20may be a way to use an adhesive or welding, for example.

In this specification, the heat radiating plate10is an example of a “first member”. The water jacket20is an example of a “second member”.

To cool a cooling target in contact with the heat radiating plate10, a refrigerant that is a liquid with a viscosity flows through the cooling apparatus1. The water jacket20is coupled with a supply pipe71for supplying the refrigerant to the cooling apparatus1. The water jacket20is coupled with a drain pipe72for draining the refrigerant, which has cooled the cooling target, from the cooling apparatus1. The refrigerant is supplied to the cooling apparatus1by a pump (not illustrated).

In the following description, X, Y, and Z axes are defined. The X, Y, and Z axes are perpendicular to each other. The X, Y, and Z axes are applied to all diagrams used in the following description. As illustrated inFIG.1, one direction along the X-axis is referred to as an X1 direction, and a direction opposite to the X1 direction is referred to as an X2 direction. The X1 and X2 directions are included in an X-axis direction. The X-axis direction is a direction along the X-axis. Similarly, two directions along the Y-axis are referred as Y1 and Y2 directions. The Y1 and Y2 directions are opposite to each other. The Y1 and Y2 directions are included in a Y-axis direction. The Y-axis direction is a direction along the Y-axis. Two directions along the Z-axis are referred to as Z1 and Z2 directions. The Z1 and Z2 directions are opposite to each other. The Z1 and Z2 directions are included in a Z-axis direction. The Z-axis direction is a direction along the Z-axis.

InFIG.1, the Y1 direction is a direction in which the refrigerant is supplied to, and drained from, the cooling apparatus1. The Y1 direction is an example of a flow direction, which is a direction in which the refrigerant flows. When a bottom surface of the water jacket20is arranged on a horizontal surface, the X-axis direction is a direction on the horizontal surface, which is perpendicular to the Y-axis. The Z-axis direction, which is perpendicular to the X and Y axes, is a direction in which the heat radiating plate10and the water jacket20overlap.

The cooling apparatus1cools the cooling target. The cooling target is an object to be cooled by the cooling apparatus1. In the first embodiment, an example of the cooling target is each of semiconductor modules50A to50C. “Semiconductor module” means a module including a resin case housing a semiconductor element. The semiconductor element is, or includes, for example, a semiconductor chip including a switching element, such as an Insulated Gate Bipolar Transistor (IGBT) and a Metal Oxide Semiconductor Field Effect Transistor (MOSFET). The semiconductor apparatus5includes the cooling apparatus1and the semiconductor modules50A to50C. The three semiconductor modules50A to50C are in contact with three regions40A to40C, respectively. The regions40A to40C are included in the heat radiating plate10. In other words, the semiconductor modules50A to50C are in contact with the heat radiating plate10. The refrigerant is supplied to the water jacket20via the supply pipe71. The supplied refrigerant cools the semiconductor modules50A to50C in contact with the regions40A to40C, respectively. The refrigerant, which has cooled the semiconductor modules50A to50C, is drained in the Y1 direction from the water jacket20via the drain pipe72.

FIG.2is a plan view of the heat radiating plate10when viewed from the Z1 direction.FIG.3is a plan view of the water jacket20when viewed from the Z2 direction.FIG.4is a cross sectional view illustrating the cooling apparatus1, the supply pipe71, and the drain pipe72in a cross section C1inFIG.1.

As illustrated inFIGS.2and4, the heat radiating plate10includes a first base plate11and a plurality of pin fins12.

The first base plate11is a plate-shaped member on which each cooling target is arranged. The first base plate11is a flat plate-shaped member including an arranging surface13and a heat radiating surface14. The arranging surface13and the heat radiating surface14is each a plane parallel to an X-Y plane. The arranging surface13is a surface opposite to the heat radiating surface14. The heat radiating surface14is a surface opposite to the arranging surface13. The arranging surface13is an example of a “first surface.” The heat radiating surface14is an example of a “second surface.”

The cooling targets are arranged on the arranging surface13. The arranging surface13includes the rectangular-shaped regions40A to40C spaced apart from each other in the X1 direction. The respective cooling targets are arranged on the respective regions40. In other words, the cooling targets are arranged in the X1 direction on the arranging surface13. Each cooling target is fixed to the arranging surface13with, for example, an adhesive.

As described above, the first base plate11may preferably be a flat plate parallel to the X-Y plane, but not limited to this aspect. For example, the arranging surface13of the first base plate11may be processed in accordance with a shape of the cooling target to be arranged on the arranging surface13. The heat radiating surface14of the first base plate11may include a slope, or the heat radiating surface14may be a curved surface.

The plurality of pin fins12are portions for radiating heat from each cooling target in contact with the arranging surface13. The plurality of pin fins12are spaced apart from each other on the heat radiating surface14. Each pin fin12is a columnar protrusion protruding in the Z2 direction from the heat radiating surface14. As illustrated inFIG.4, each pin fin12may preferably not be in contact with the water jacket20. Each pin fin12may be bonded or welded to the first base plate11. Alternatively, the first base plate11and the pin fins12may be formed integrally with a mold.

Each pin fin12is a member for transferring heat, which is conducted from the cooling targets via the first base plate11, to the refrigerant. Specifically, the heat generated in the cooling targets is conducted from the arranging surface13via the inside of the first base plate11to the heat radiating surface14in the Z2 direction, and it is then conducted from the first base plate11to each pin fin12. The heat reaching each pin fin12is conducted from a root of each pin fin12to a tip of each pin fin12in the Z2 direction.

As illustrated inFIG.2, the plurality of pin fins12are divided into a plurality of rows. Each of the rows is a set of two or more pin fins12arranged spaced apart from each other along the X-axis. The rows are arranged spaced apart from each other in the Y-axis direction.

The pin fins12in each row may be preferably equally spaced from each other in the X-axis direction. However, the embodiment is not limited to this aspect. The pin fins12in each row may be unequally spaced from each other in the X-axis direction.

As illustrated inFIG.2, the pin fins12may be preferably staggered on the first base plate11. “Staggered” means an arrangement in which pin fins12included in one row of the rows are alternated with pin fins12included in a row adjacent to the one row when viewed from the Y1 direction.

The pin fins12are staggered on the first base plate11. Therefore, after the refrigerant flowing in the Y1 direction passes through a space between two pin fins12included in one row, the refrigerant comes into contact with a front surface of another pin fin12immediately. Therefore, it is possible to radiate large amounts of heat from the pin fins12.

When a situation, in which the pin fins12are staggered on the first base plate11, is viewed from the Y1 direction, one pin fin12included in one row of the rows may be preferably positioned at a midpoint between two pin fins12, which are next to each other in the X-axis direction, included in a row adjacent to the one row. However, the embodiment is not limited to this aspect. For example, when viewed from the Y1 direction, the one pin fin12included in the one row may be positioned at a place different from the midpoint between the two pin fins12, which are next to each other in the X-axis direction, included in the row adjacent to the one row.

In this specification, the pin fin12is an example of a “radiating fin.”

As illustrated inFIGS.3and4, the water jacket20includes protrusions21A to21F and a second base plate22. The second base plate22includes a facing surface24as a surface facing the heat radiating surface14of the first base plate11. The facing surface24is a plane parallel to the X-Y plane. The facing surface24is an example of a “third surface.” A space between the heat radiating surface14and the facing surface24is a flow path of a refrigerant. As illustrated inFIG.4, the second base plate22may include a protrusion protruding in the Z1 direction.

The water jacket20may preferably be made of a metal, in particular, a metal with a relatively high heat transfer coefficient such as copper and aluminum.

The protrusions21A to21F and the second base plate22may be formed integrally with a mold. A way to form the protrusions21A to21F and the second base plate22is not limited to a way to integrally form the protrusions21A to21F and the second base plate22. The protrusions21A to21F may be joined to the second base plate22by bonding or by welding.

As described above, in the water jacket20, the facing surface24of the second base plate22may be preferably spaced apart from a tip of each pin fin12protruding in the Z2 direction. On the other hand, when the cooling apparatus1is manufactured in a state in which the tip of each pin fin12protruding in the Z2 direction is in contact with the second base plate22or in a state in which the tip of each pin fin12protruding in the Z2 direction and the second base plate22are integrated, it is necessary to reduce their dimensional tolerances compared with a configuration in which the tip of each pin fin12protruding in the Z2 direction is apart from the second base plate22. A configuration with reduced dimensional tolerance increases manufacturing cost of the cooling apparatus1. In the embodiment, a space is present between the tip of each pin fin12protruding in the Z2 direction and the second base plate22. Therefore, compared to the configuration in which the tip of each pin fin12protruding in the Z2 direction is in contact with the second base plate22, dimensional tolerance can be increased. Consequently, manufacturing cost is reduced. However, the embodiment is not limited to this aspect. For example, the tip of each pin fin12protruding in the Z2 direction may be in contact with the second base plate22. The tip of each pin fin12protruding in the Z2 direction and the second base plate22may be integrated.

InFIG.3, dotted lines represent images of the plurality of pin fins12projected onto the second base plate22in the Z2 direction. The protrusions21A to21F are arranged on the facing surface24. The protrusions21A to21F are arranged between the pin fins12in the flow direction of the refrigerant. Specifically, each of the protrusions21A to21F protrudes in the Z1 direction from the facing surface24of the second base plate22toward a space. The space exists between the pin fins12in the flow direction of the refrigerant. Each of the protrusions21A to21F is an example of a “first protrusion.” Each of the protrusions21A to21E may be an example of a “second protrusion” instead of an example of the “first protrusion.” The second protrusion is positioned upstream in the flow direction from the first protrusion of the refrigerant. Each of the protrusions21A to21F extends linearly in the X1 direction over an entire width of the facing surface24. Focusing on the rows obtained by dividing the pin fins12, in plan view, one protrusion21is arranged between adjacent rows in the Y1 direction.

The protrusions21A to21F may preferably extend in the X-axis direction inFIG.3. However, the embodiment is not limited to this aspect. For example, a plurality of protrusions21may be spaced apart from each other in the X-axis direction inFIG.3. A direction in which the protrusions21A to21F extend is not limited to the X-axis direction inFIG.3as long as the direction, in which the protrusions21A to21F extend, intersects a flow path direction of the refrigerant (the flow direction). “Flow path direction of the refrigerant” corresponds to the Y1 direction.

InFIG.3, a plurality of protrusions21A-21F is illustrated, but the embodiment is not limited to this aspect. For example, only one of the protrusions21A to21F may be arranged.

FIG.5is an enlarged view of a region C2inFIG.4. InFIG.5, the positions of the pin fins12A and12C are shifted in the X1 direction from the positions of the pin fins12B and12D. Therefore, the pin fins12A and12C are represented by dotted lines. The protrusion21B is arranged on the second base plate22. The protrusion21B is arranged between the pin fin12A and the pin fin12B. Similarly, the protrusion21C is arranged on the second base plate22. The protrusion21C is arranged between the pin fin12B and pin fin12C. The protrusion21D is arranged on the second base plate22. The protrusion21D is arranged between the pin fin12C and the pin fin12D.

The protrusions21A to21F include slopes25A to25F, respectively. The slopes25A to25F are each inclined to the facing surface24of the second base plate22. Each of the slopes25A to25F is an example of a “first slope.” Each of the slopes25A to25E may be an example of a “second slope” instead of an example of a “first slope.” The second slope is included in the second protrusion. The slopes25A to25F include tips26A to26F, respectively. The tips26A to26F are each an example of a “first end.” Each of the tips26A to26E may be an example of a “third end” instead of an example of a “first end.” The slopes25A to25F further include ends27A to27F, respectively. The ends27A to27F are each an example of a “second end.” Each of the ends27A to27E may be an example of a “fourth end” instead of an example of a “second end.” The tips26A to26F are closer to the heat radiating surface14of the first base plate11than the ends27A to27F, respectively. The ends27A to27F are closer to the facing surface24of the second base plate22than the tips26A to26F, respectively. The tip26A is positioned downstream in the flow direction of the refrigerant from the end27A. Similarly, the tips26B to26F are positioned downstream in the flow direction Y1 of the refrigerant from the ends27B to27F, respectively. A slope angle α between the facing surface24and the slope25is greater than 0° and less than 90°. In this embodiment, the slopes25A to25F are each a plane. A shape of a cross section, which is perpendicular to the X-axis, of each of the protrusions21A to21F, is a right triangle. The hypotenuse of the right triangle is impacted by the refrigerant flowing in the flow direction Y1.

The protrusions21A to21F each include back surfaces28A to28F, respectively, in addition to the slopes25A to25F. The back surfaces28A to28F are positioned downstream in the flow direction Y1 of the refrigerant from the slopes25A to25F, respectively. The back surfaces28A to28F are each perpendicular to the facing surface24.

The tips26A to26F of the protrusions21A to21F protruding in the Z1 direction are closer to the heat radiating surface14than tips15A to15F of the pin fins12A to12F protruding in the Z2 direction, respectively. In other words, a distance d1 from the facing surface24to each of the tips26A to26F of the protrusions21A to21F is greater than a distance d2 from the facing surface24to each of the tips15A to15F of the pin fins12A to12F.

InFIG.5, the heights d1 of the protrusions21B to21D in the Z-axis direction are equal to each other, but the embodiment is not limited to this aspect. Specifically, the heights d1 of the protrusions21B to21D in the Z-axis direction may be different from each other. In particular, the protrusions21B to21D may be arranged in ascending order of height d1 along the flow direction Y1 of the refrigerant.

InFIG.5, the slope angles of the slopes25B to25D, that is, the slope angles αB to αD between the slopes25B to25D and the facing surface24are equal to each other, but the embodiment is not limited to this aspect. Specifically, the slope angles αA to αF of the slopes25A to25F are different from each other. In particular, the slope angles αA to αF of the slopes25A to25F may be arranged in ascending order of the slope angle along the flow direction Y1 of the refrigerant. Since the cooling apparatus1includes such a configuration, as described below, it is possible to reduce difference between degrees to which the refrigerant approaches the roots of the pin fins12in a range from an upstream side to a downstream side in the flow direction Y1 of the refrigerant.

InFIG.5, the positions of the protrusions21B to21D on the facing surface24in the Y-axis direction are each a position between the pin fins12in the flow direction of the refrigerant, and the protrusions21B to21D are apart from the pin fins12. However, the embodiment is not limited to this aspect. For example, the back surfaces28B to28D of the protrusions21B to21D may be respectively in contact with the pin fins12B to12D positioned downstream in the flow direction Y1 of the refrigerant from the protrusions21B to21D. Each of the back surfaces28B to28D may be in contact with at least one pin fin12.

FIG.6is a diagram illustrating a flow of the refrigerant in the region C2. InFIG.6, each of the arrows shows the flow of the refrigerant. As illustrated by arrow “FA1” inFIG.6, when the refrigerant flowing in the Y1 direction comes into contact with the slope25B of the protrusion21B, the refrigerant moves along the slope25B. Thereafter, when the refrigerant comes into contact with the pin fin12B, as illustrated by arrow “FB1” inFIG.6, the refrigerant flows along the pin fin12B in the Z1 direction.

Some of the refrigerant that rises along the slope25B moves along both the back surface28B of the protrusion21B and the pin fin12B in the Z2 direction, and passes through a gap between the pin fin12B and the facing surface24in the Y1 direction. As illustrated by arrow “FA2” inFIG.6, when the refrigerant, which has passed through the gap between the pin fin12B and the facing surface24, comes into contact with the slope25C of the protrusion21C, the refrigerant moves along the slope25C. Thereafter, when the refrigerant comes into contact with the pin fin12C, as illustrated by arrow “FB2” inFIG.6, the refrigerant flows along the pin fin12C in approximately the Z1 direction.

Similarly, some of the refrigerant that rises along the slope25C moves along both the back surface28C of the protrusion21C and the pin fin12C in the Z2 direction, and passes through a gap between the pin fin12C and the facing surface24in the Y1 direction. As illustrated by arrow “FA3” inFIG.6, when the refrigerant, which has passed through the gap between the pin fin12C and the facing surface24, comes into contact with the slope25D of the protrusion21D, the refrigerant moves along the slope25D.

Therefore, the refrigerant approaches the roots of the pin fins12B and12C. Consequently, the cooling target in contact with the arranging surface13of the first base plate11is efficiently cooled. Specifically, as described above, the heat generated in the cooling target conducts in the Z2 direction inside the first base plate11from the arranging surface13to the heat radiating surface14and then conducts from the first base plate11to each pin fin12. Due to an increase in the flow rate of the refrigerant approaching the root of each pin fin12, the heat conducted from the cooling target to each pin fin12is radiated more efficiently. Therefore, the cooling target is cooled more efficiently.

As the slope angles of the slopes25A to25F, that is, the slope angles αA to αF between the slopes25A to25F and the facing surface24decrease, resistance of the refrigerant flowing between the heat radiating surface14and the facing surface24decreases. This causes reduction in pressure drop based on difference between pressure of the refrigerant at an inlet of the cooling apparatus1and pressure of the refrigerant at an outlet of the cooling apparatus1. The smaller the pressure drop, the smaller the load to flow the refrigerant into the cooling apparatus1. Therefore, there is an advantage in reducing the frequency of failure of a pump for supplying refrigerant to the cooling apparatus1. On the other hand, the greater the slope angles αA to αF of the slopes25A to25F, the greater an angle between a direction, in which the refrigerant flows along the slopes25A to25F, and the facing surface24. Therefore, an amount of refrigerant approaching the roots of the pin fins12increases. Consequently, there is an advantage in that the cooling target in contact with the arranging surface13of the first base plate11is cooled more efficiently.

Fluid analysis of four models were carried out. The four models included a model having protrusions each including a slope with a slope angle of 30°, a model having protrusions each including a slope with a slope angle of 45°, a model having protrusions each including a slope with a slope angle of 60°, and a model having protrusions each including a slope with a slope angle of 75°. In the results of fluid analysis, the model with the slope angle of 30° had the smallest pressure drop based on the difference between the pressure of the refrigerant at the inlet of the cooling apparatus1and the pressure of the refrigerant at the outlet of the cooling apparatus1of the four models. On the other hand, the model with the slope angle of 75° had the greatest amount of refrigerant approaching the roots of the pin fins12.

FIG.7is a diagram illustrating flow of refrigerant in a cooling apparatus50that is a first comparative example. For components in common with the cooling apparatus1and the cooling apparatus50, the same reference signs are used, and explanations of their functions are omitted. InFIG.7, each of arrows shows the flow of refrigerant. The longer the length of the arrow, the higher the flow velocity.

The cooling apparatus50differs from the cooling apparatus1in that the protrusions21A to21F are not arranged. Therefore, for example, after the refrigerant, which has passed through the gap between the pin fins12B and the facing surface24, flows into a space between the pin fins12B and12C in a direction illustrated by arrow “FD1” inFIG.7, the refrigerant is not directed in the Z1 direction. Consequently, as illustrated by arrow “FE1” inFIG.7, the flow of the refrigerant is in approximately the Y-axis direction in a middle region between the pin fins12B and12C. The pin fin12C includes an end16C facing the pin fin12B. As illustrated in a region “FF1” inFIG.7, unlike the cooling apparatus1, the flow of the refrigerant in the Z1 direction does not occur near the end16C. Therefore, a flow rate of the refrigerant is reduced in a vicinity of the root of the pin fin12C. Consequently, an amount of heat exchange between the refrigerant and the cooling target in the cooling apparatus50becomes less than that of the cooling apparatus1.

As illustrated by arrows “FD1” and “FD2” inFIG.7, a force of the flow of the refrigerant in the Z1 direction, after the refrigerant passes through the gap between the pin fin12C and the facing surface24, is weaker than a force of the flow of the refrigerant in the Z1 direction after the refrigerant passes through the gap between the pin fin12B and the facing surface24of the second base plate22. As illustrated by arrows in respective regions “FE1” and “FE2” inFIG.7, flow velocity of a downstream refrigerant, that is, flow velocity of a refrigerant in a vicinity of the pin fin12D is lower than flow velocity of an upstream refrigerant, that is, flow velocity of a refrigerant in a vicinity of the pin fin12B. A flow rate of the downstream refrigerant is less than a flow rate of the upstream refrigerant. In particular, in a region close to the first base plate11, flow velocity of the downstream refrigerant is lower than flow velocity of the upstream refrigerant, and the flow rate of the downstream refrigerant is less than the flow rate of the upstream refrigerant. As will be understood fromFIG.4, this is because directing the flow of the refrigerant in the Z1 direction increases as the gap between the pin fin12and the facing surface24is closer to the supply pipe71.

Therefore, as described above, in the cooling apparatus1, the heights of the protrusions21A to21F in the Z axial direction, that is, the distances d1 from the facing surface24to the tips26A to26F may be preferably arranged in ascending order of height in the flow direction Y1 of the refrigerant. In this case, it is possible to reduce difference between degrees to which the refrigerant approaches the roots of the pin fins12in the range from the upstream side to the downstream side.

Similarly, with respect to the slope angles αA to αF of the slopes25A to25F in the cooling apparatus1, as the slope25is closer to the downstream side of the refrigerant, the slope angle of the slope25may be preferably greater. In this case, it is possible to reduce difference between degrees to which the refrigerant approaches the roots of the pin fins12in the range from the upstream side in the flow direction Y1 of the refrigerant to the downstream side in the flow direction Y1 of the refrigerant.

FIG.8is a diagram illustrating a flow of a refrigerant in a cooling apparatus60that is a second comparative example. For components in common with the cooling apparatus1and the cooling apparatus60, the same sign is used and explanations of their functions are omitted. InFIG.8, each of the arrows shows flow of the refrigerant.

The cooling apparatus60differs from the cooling apparatus1in that the cooling apparatus60includes protrusions61A to61F with a rectangular cross section perpendicular to the X-axis instead of the protrusions21A to21F with the right triangular cross section perpendicular to the X-axis. Specifically, a shape of each of the cross sections, which is perpendicular to the X-axis, of the protrusions61A to61F is a rectangular shape having two sides parallel to the Y-axis direction and two sides parallel to the Z-axis direction.

As illustrated by arrow “FG1” inFIG.8, when the refrigerant flowing in the Y1 direction comes into contact with the protrusion61B, the refrigerant moves in the Z1 direction along a surface, which is perpendicular to the X-axis, included in the protrusion61B, and then the refrigerant changes a direction of movement of the refrigerant to the Y1 direction at a corner of the surface, which is perpendicular to the X-axis, included in the protrusion61B. In other words, the refrigerant flowing in the vicinity of the protrusion61B comes into contact with the pin fin12B without being directed in the Z1 direction. Therefore, as will be understood from a comparison of the flow indicated by arrow “FH1” inFIG.8with the flow indicated by arrow “FB1” inFIG.6, flow velocity of the refrigerant in contact with the pin fin12B as illustrated inFIG.8is slow compared to that in the cooling apparatus1. A flow rate of the refrigerant in contact with the pin fin12B in the cooling apparatus60is small compared to that in the cooling apparatus1.

Some of the refrigerant flowing in the Y1 direction moves in the Z2 direction along both a back surface of the protrusion61B and the pin fin12B. As illustrated by arrow “FG2” inFIG.8, when the refrigerant, which has passed through a gap between the pin fin12B and the facing surface24, comes into contact with the protrusion61C, the refrigerant moves in the Z1 direction along a surface, which is perpendicular to the X-axis, included in the protrusion61C. Thereafter, the refrigerant moving in the Z1 direction changes the direction of movement of the refrigerant to the Y1 direction at a corner of the surface, which is perpendicular to the X-axis, included in the protrusion61C. In other words, the refrigerant flowing in the vicinity of the protrusion61C comes into contact with the pin fin12C without being directed in the Z1 direction. Therefore, as will be understood from a comparison of the flow indicated by arrow “FH2” inFIG.8with the flow indicated by arrow “FB2” inFIG.6, flow velocity of the refrigerant in contact with the pin fin12C as illustrated inFIG.8is slow compared to that in the cooling apparatus1. A flow rate of the refrigerant in contact with the pin fin12C in the cooling apparatus60is low compared to that of the cooling apparatus1.

Similarly, as illustrated by arrow “FG3” inFIG.8, when the refrigerant, which has passed through a gap between the pin fin12C and the facing surface24, comes into contact with the protrusion61D, the refrigerant moves in the Z1 direction along a surface, which is perpendicular to the X-axis, included in the protrusion61D. Thereafter, the refrigerant moving in the Z1 direction changes direction of movement of the refrigerant to the Y1 direction at a corner of the surface, which is perpendicular to the X-axis, included in the protrusion61D.

Therefore, in the cooling apparatus60, the refrigerant approaches the roots of the pin fins12B and12C. However, an amount of the refrigerant approaching the roots of the pin fins12B and12C is small compared to that in the cooling apparatus1.

On the other hand, in the cooling apparatus1, the surfaces of the protrusions21A to21F in contact with the refrigerant flowing in the flow direction Y1 are the slopes25A to25F inclined to the facing surface24. Therefore, the amount of refrigerant approaching the roots of the pin fins12B and12C is large compared to that in the cooling apparatuses50and60. Consequently, the cooling target in contact with the arranging surface13is cooled more efficiently.

1.2 Effects of First Embodiment

This embodiment includes the following effects.

The cooling apparatus1according to the embodiment includes the heat radiating plate10including the arranging surface13in contact with the cooling target, the heat radiating surface14opposite to the arranging surface13, and the pin fins12protruding from the heat radiating surface14. The cooling apparatus1further includes the water jacket20including the facing surface24facing the heat radiating surface14. The refrigerant flows between the heat radiating plate10and the water jacket20. The water jacket20includes a protrusion21protruding from the facing surface24toward the space between the pin fins12in the flow direction of the refrigerant. The protrusion21includes the slope25inclined to the facing surface24. The slope25includes the tip26and the end27. The tip26is closer to the heat radiating surface14than the end27. The end27is closer to the facing surface24than the tip26. The tip26is positioned downstream in the flow direction of the refrigerant from the end27.

According to this configuration, the refrigerant passing near a tip of a pin fin12protruding from the heat radiating surface14approaches a root of another pin fin12due to the protrusion21protruding from the facing surface24. Therefore, the cooling target in contact with the arranging surface13is cooled efficiently compared to a configuration without the protrusion21.

In the cooling apparatus1according to the embodiment, the facing surface24may face the heat radiating surface14with the facing surface24apart from the tips15of the pin fins12. The tips26A to26F of the protrusions21A to21F may be closer to the heat radiating surface14than the tips15of the pin fins12.

According to this configuration, the protrusion21protruding from the facing surface24causes the refrigerant passing through the gap between the tip15of the pin fin12protruding from the heat radiating surface14and the facing surface24to flow toward a position shifted in the Z1 direction from the tip15of the pin fin12. Therefore, the refrigerant approaches the root of another pin fin12. Consequently, the cooling target in contact with the arranging surface13is cooled efficiently compared to a configuration in which the tips26A to26F of the protrusions21A to21F are closer to the facing surface24than the tips15of the pin fins12.

In the cooling apparatus1according to the embodiment, the water jacket20may include the plurality of protrusions21arranged along the flow direction of the refrigerant.

According to this configuration, since the plurality of protrusions21are arranged along the flow direction, an amount of the refrigerant approaching the roots of the pin fins12increases. Therefore, the cooling target in contact with the arranging surface13is cooled more efficiently.

In the cooling apparatus1according to the embodiment, the protrusion21F positioned downstream in the flow direction of the refrigerant from the protrusion21A may be higher than the protrusion21A positioned upstream in the flow direction of the refrigerant from the protrusion21F.

In the cooling apparatus1, the strength of flow of the refrigerant toward the heat radiating surface14after the refrigerant passes near the protrusion21is weaker as the refrigerant is closer to a position located downstream in the flow direction of the refrigerant. According to the above configuration, the protrusion21is higher as the protrusion21is closer to the position located downstream in the flow direction. Therefore, it is possible to reduce a difference between degrees to which the refrigerant approaches the roots of the pin fins12in the range from the upstream side in the flow direction Y1 of the refrigerant to the downstream side in the flow direction Y1 of the refrigerant.

In the cooling apparatus1according to the embodiment, the slope angle of the slope25F of the protrusion21F positioned downstream in the flow direction of the refrigerant may be greater than that of the slope25A of the protrusion21A positioned upstream in the flow direction of the refrigerant.

In the cooling apparatus1, the flow of the refrigerant toward the heat radiating surface14after the refrigerant passes near the protrusion21decreases as the refrigerant approaches the position located downstream in the flow direction of the refrigerant. According to the above configuration, the slope angle of the slope25of the protrusion21is steeper as the protrusion21is closer to the position located downstream in the flow direction of the refrigerant. Therefore, it is possible to reduce the difference between degrees to which the refrigerant approaches the roots of the pin fins12in the range from the upstream side in the flow direction Y1 of the refrigerant to the downstream side in the flow direction Y1 of the refrigerant.

In the cooling apparatus1according to the embodiment, the protrusions21may extend between the pin fins12in the direction intersecting the flow direction of the refrigerant.

According to this configuration, since the protrusion21extends between the pin fins12in the direction intersecting the flow direction of the refrigerant, when viewed from the flow direction of the refrigerant, it is possible to cause the refrigerant flowing between pin fins12to approach the root of another pin fin12.

In the cooling apparatus1according to the embodiment, an arrangement of the pin fins12on the heat radiating surface14may be staggered.

According to this configuration, when viewed from the flow direction of the refrigerant, the refrigerant flowing and passing between the pin fins12comes into contact with a front surface of another pin fin12immediately, compared to a configuration in which an arrangement of the pin fins12on the second surface is in a grid pattern. This increases the flow resistance of the refrigerant. This makes it possible to radiate more heat from the pin fins12.

In the cooling apparatus1of the embodiment, the back surface28of the protrusion21may be in contact with the pin fin12.

According to this configuration, a distance of the slope25of the protrusion21, on which the refrigerant having passed through the vicinity of the tip15of the pin fin12flows until the refrigerant impacts the next pin fin12, becomes longer. This increases the amount of the refrigerant approaching the roots of the pin fins12. Therefore, the cooling target in contact with the arranging surface13is cooled more efficiently.

In the cooling apparatus1according to the embodiment, the protrusions21may each be made of a porous member.

According to this configuration, the protrusions21are each made of a porous member. This expands an area of contact between the protrusions21and the refrigerant, and disturbs the flow of the refrigerant in the vicinity of the protrusions21. Therefore, the refrigerant comes into contact with the pin fins12from various directions. Consequently, it is possible for the pin fin12to radiate more heat.

2. Second Embodiment

A cooling apparatus according to a second embodiment will be described below with reference toFIG.9.

2.1 Configuration of Second Embodiment

FIG.9is a cross sectional view of a cooling apparatus1A according to the second embodiment.FIG.9relates toFIG.6. To simplify explanation, for components in common with the cooling apparatus1according to the first embodiment and the cooling apparatus1A according to the second embodiment, the same signs are used and explanations of their functions are omitted. In the following, the points in which the cooling apparatus1A according to the second embodiment differs from the cooling apparatus1according to the first embodiment will be mainly described.

The cooling apparatus1A differs from the cooling apparatus1in that the cooling apparatus1A includes protrusions29A to29F instead of the protrusions21A to21F. In the protrusions21A to21F, the slopes25A to25F are each planar. The protrusions29A to29F are different from the protrusions21A to21F in that the protrusions29A to29F include curved slopes30A to30F respectively.

Specifically, the gradient of each of the slopes30A to30F to the facing surface24becomes steeper in the flow direction of the refrigerant. The slope30includes a first end and a second end. The first end and the second end of the slope30are both ends of the slope30. The first end of the slope30is closest to the heat radiating surface14in the slope30. The first end of the slope30is positioned downstream in the flow direction of the refrigerant from the second end of the slope30. The slope30increases from the first end of the slope30toward the second end of the slope30. The slope30increases from the second end of the slope30toward the first end of the slope30. The slope30includes a first partial surface, and a second partial surface that is closer to the second end than the first partial surface. The gradient of the first partial surface is greater than the gradient of the second partial surface.

As illustrated by arrow “FA4” inFIG.9, when the refrigerant flowing in the Y1 direction comes into the slope30B of the protrusion29B, the refrigerant moves along the slope30B. Thereafter, when the refrigerant comes into contact with the pin fin12B, the refrigerant flows along the pin fin12B in the Z1 direction, as illustrated by arrow “FB3” inFIG.9.

In the cooling apparatus1A according to the second embodiment, as the refrigerant moves along the slope30B of the protrusion29B, an angle of a movement direction of the refrigerant to the facing surface24becomes steeper. Therefore, the flow of the refrigerant illustrated by arrow “FA4” is directed in the Z1 direction strongly compared to the first embodiment. Therefore, as will be understood from a comparison of the flow indicated by arrow “FB3” inFIG.9, with the flow indicated by arrow “FB1” inFIG.6, flow velocity of the refrigerant in contact with the pin fin12B as illustrated inFIG.9, is high compared to that of the first embodiment. A flow rate of the refrigerant in contact with the pin fin12B in the cooling apparatus60is high compared to that in the first embodiment.

Some of the refrigerant flowing in the FA4direction moves in the Z2 direction along both a back surface28B of the protrusion29B and the pin fin12B, and then passes through a gap between the pin fin12B and the facing surface24in the Y1 direction. As illustrated by arrow “FA5” inFIG.9, when the refrigerant, which has passed through the gap between the pin fin12B and the facing surface24, comes into contact with the slope30C of the protrusion29C, the refrigerant moves along the slope30C. Thereafter, when the refrigerant comes into contact with the pin fin12C, the refrigerant flows along the pin fin12C in the Z1 direction as illustrated by arrow “FB4” inFIG.9.

Similar to a case in which the refrigerant moves along the slope30B of the protrusion29B, as the refrigerant moves along the slope30C of the protrusion29C, an angle of a movement direction of the refrigerant to the facing surface24becomes steeper. Therefore, the flow of the refrigerant illustrated by arrow “FA5” is directed in the Z1 direction strongly compared to the first embodiment. Therefore, as will be understood from a comparison of the flow indicated by arrow “FB4” inFIG.9with the flow indicated by arrow “FB2” inFIG.6, a flow rate of the refrigerant in contact with the pin fin12C as illustrated inFIG.9is high compared to that of the first embodiment.

Some of the refrigerant flowing in the FA5direction moves in the Z2 direction along both a back surface28C of the protrusion29C and the pin fin12C, and then passes through a gap between the pin fin12C and the facing surface24in the Y1 direction. As illustrated by arrow “FA6” inFIG.9, when the refrigerant, which has passed through the gap between the pin fin12C and the facing surface24, comes into contact with the slope30D of the protrusion29D, the refrigerant moves along the slope30D.

Therefore, compared to the cooling apparatus1according to the first embodiment, the refrigerant approaches the roots of the pin fins12B and12C more closely.

2.2 Effects of Second Embodiment

This embodiment includes the following effects.

In the cooling apparatus1A according to this embodiment, the slopes30A to30F include curved surfaces, and in particular, the gradient of each of the slopes30A to30F becomes steeper in the flow direction of the refrigerant. In other words, the gradient of the slope30increases from the second end of the slope30toward the first end of the slope30.

According to this configuration, a degree increases to which the refrigerant approaches the roots of the pin fins12protruding from the heat radiating surface14, compared to the cooling apparatus1according to the first embodiment. Therefore, the cooling target in contact with the arranging surface13is cooled more efficiently.

The gradient of each of the slopes30A to30F becomes more gradual in a direction opposite to the flow direction of the refrigerant. In other words, the gradient of the slope30decreases from the first end of the slope30toward the second end of the slope30.

This configuration results in a smaller pressure drop between an inlet of the cooling apparatus1A for the refrigerant and an outlet of the cooling apparatus1A for the refrigerant, compared to the cooling apparatus1according to the first embodiment in which the gradient of the slope is steep from the upstream side of the refrigerant.

A cooling apparatus according to a third embodiment will be described below with reference toFIG.10.

3.1 Configuration of Third Embodiment

FIG.10is a cross sectional view of a cooling apparatus1B according to the third embodiment.FIG.10relates toFIG.6. To simplify explanation, for components in common with the cooling apparatus1according to the first embodiment and the cooling apparatus1B according to the third embodiment, the same reference signs are used, and explanations of their functions are omitted. In the following, the points in which the cooling apparatus1B according to the third embodiment differs from the cooling apparatus1according to the first embodiment will be mainly described.

The cooling apparatus1B differs from the cooling apparatus1in that the cooling apparatus1B includes pin fins17instead of the pin fins12. Each pin fin17includes a tip18instead of the tip15of each pin fin12. Each tip18is an example of a “tip end.” Each tip18includes a first corner and a second corner. The first corner and the second corner of each tip18are both ends of each tip18. The first corner is positioned upstream in the flow direction Y1 from the second corner. The second corner in positioned downstream in the flow direction Y1 from the first corner. The first corner or the second corner is a rounded corner.

As illustrated inFIG.10, each tip18differs from each tip15in that at least the corner (the second corner) positioned downstream in the flow direction of the refrigerant is R-shaped. An “R-shape” refers to a shape of the tip18in which a side surface of the tip18and a bottom surface of the tip18are coupled to each other with a curved surface. In the cross sectional view illustrated inFIG.10, the side surface and the bottom surface are continuous with each other in an arc shape.

FIG.10illustrates the tip18with an R-shaped corner formed on an entire circumference of a circle joining the side surface of the tip18with the bottom surface of the tip18, in addition to the R-shaped corner positioned downstream in the refrigerant.

As illustrated by arrow “FA7” inFIG.10, when the refrigerant flowing in the Y1 direction comes into contact with the slope25B of the protrusion21B, the refrigerant moves along the slope25B. Thereafter, when the refrigerant comes into contact with the pin fin17B, as illustrated by arrow “FB5” inFIG.10, the refrigerant flows along the pin fin17B in the Z1 direction.

Some of the refrigerant that rises along the slope25B moves in the Z2 direction along both the back surface28B of the protrusion21B and the pin fin17B, and then passes through a gap between the pin fin17B and the facing surface24in the Y1 direction.

Of the refrigerant that flows through the gap between the pin fin17B and the facing surface24in the Y1 direction, the refrigerant flowing near the pin fin17B flows along the tip18B of the pin fin17B due to a “Coanda effect” in which a viscous fluid flows along a wall that makes up a flow path. Therefore, as illustrated by arrow “FC1” inFIG.10, the refrigerant flowing near the pin fin17B is directed in the Z1 direction by passing through a vicinity of the tip18B.

The refrigerant is viscous. Therefore, of the refrigerant that flows through the gap between the pin fin17B and the facing surface24in the Y1 direction, the refrigerant flowing near the facing surface24is also directed in the Z1 direction as the refrigerant flowing near the pin fin17B is directed in the Z1 direction. In other words, the refrigerant flowing near the facing surface24is directed in the Z1 direction by the flow of the refrigerant indicated by arrow “FC1.” Therefore, the flow of the refrigerant illustrated by arrow “FA8” is directed in the Z1 direction strongly compared to the first embodiment. Therefore, as will be understood from a comparison of the flow indicated by arrow “FB6” inFIG.10with the flow indicated by arrow “FB2” inFIG.6, flow velocity of the refrigerant in contact with the pin fin17C as illustrated inFIG.10is high compared to that of the first embodiment. A flow rate of the refrigerant in contact with the pin fin17C in the cooling apparatus1B is high compared to that of the first embodiment.

Some of the refrigerant flowing in the FA8direction moves in the Z2 direction along both the back surface28C of the protrusion21C and the pin fin17C, and then passes through a gap between the pin fin17C and the facing surface24in the Y1 direction.

Of the refrigerant that flows through the gap between the pin fin17C and the facing surface24in the Y1 direction, the refrigerant flowing near the pin fin17C flows along the tip18C of the pin fin17C due to the “Coanda effect”, as well as the flow of the refrigerant indicated by arrow “FC1.”

Therefore, as illustrated by arrow “FC2” inFIG.10, the refrigerant flowing near the pin fin17C is directed in the Z1 direction by passing through a vicinity of the tip18C.

Of the refrigerant flowing through the gap between the pin fin17C and the facing surface24in the Y1 direction, the refrigerant flowing near the facing surface24is also directed in the Z1 direction by the flow of the refrigerant indicated by arrow “FC2”. Therefore, the flow of the refrigerant illustrated by arrow “FA9” is strongly directed in the Z1 direction compared to that of the first embodiment.

A configuration in which the tip18has the R-shaped corner positioned downstream in the refrigerant, and a configuration in which the tip18has the R-shaped corner formed on the entire circumference of the circle joining the side surface of the tip18and the bottom surface of the tip18are described. However, the cooling apparatus1B according to the third embodiment is not limited to each configuration. For example, only a corner positioned upstream in the refrigerant (the first corner) may be an R-shaped corner. In this case, the refrigerant is directed both toward the gap between the pin fin17B and the facing surface24and toward the gap between the pin fin17C and the facing surface24. Therefore, it is possible to direct collisions of the refrigerant with the protrusions21C and21D. Consequently, compared to the first embodiment, the flows of the refrigerant illustrated in “FA8” and “FA9” and the flow of the refrigerant illustrated in “FB6” are strongly directed in the Z1 direction

3.2 Effects of Third Embodiment

This embodiment includes the following effects.

In the cooling apparatus1B according to this embodiment, the tip18of the pin fin17includes the R-shaped corner positioned downstream in the flow direction of the refrigerant.

The Coanda effect causes the refrigerant to flow along the tip18of the pin fin17protruding from the heat radiating surface14. According to the above configuration, the tip18of the pin fin17includes the R-shaped corner positioned downstream in the flow direction of the refrigerant. Therefore, the refrigerant flowing through the vicinity of the tip18of the pin fin17approaches the roots of the pin fins17still closer compared to the cooling apparatus1according to the first embodiment in which the tip15of the pin fin12does not include the R-shaped corner positioned downstream in the flow direction of the refrigerant. Consequently, the cooling target in contact with the arranging surface13is cooled more efficiently.

The disclosure is not limited to the embodiments described above. Specific modifications will be described below.

For example, the height of the protrusion21may decrease from the center of the protrusion21in the X-axis direction intersecting the Y1 direction, which is the flow direction of the refrigerant, to both ends of the protrusion21in the X-axis direction. This is because the supply pipe71and the drain pipe72are arranged at the center of the cooling apparatus in the X-axis direction.

FIG.11is an example of a cross sectional view of a cooling apparatus1C according to this modification when viewed from the Y1 direction. In the cooling apparatus1C, a plurality of pin fins12G to12J protrudes in the Z2 direction from the first base plate11. As illustrated inFIG.11, the plurality of pin fins12G to12J are arranged at equal intervals in the X1 direction in order of sign. Although four pin fins12G to12J are illustrated inFIG.11, the number of pin fins12may be freely selected. InFIG.11, the positions of the pin fins12G to12J are shifted in the Y1 direction from the position of a protrusion31. Therefore, the pin fins12G to12J are represented by dotted lines.

In the cooling apparatus1C, the protrusion31protrudes from the facing surface24of the second base plate22. The protrusion31extends in the X-axis direction.

FIG.11illustrates positions C1ato C3ain the X-axis direction. The position C1ais a position of a midpoint in a width (X-axis direction) of the flow path inside the cooling apparatus1C. The position C3ais a position of a vicinity of the end of the width of the flow path inside the cooling apparatus1C (specifically, a position shifted from the position C1ain the X2 direction). The position C2ais a position between the position C1aand the position C3ain the X-axis direction.

The height of the protrusion31, that is, the length of the protrusion31in the Z-axis direction, is highest at the position C1ain the X-axis direction. The height of the protrusion31gradually decreases from the position C1ato the ends of the protrusion31in the X-axis direction.

In the example illustrated inFIG.11, the height d3 of the protrusion31at the position C1ais greater than the height d4 of the protrusion31at the position C2a, and the height d4 of the protrusion31at the position C2ais greater than the height d5 of the protrusion31at the position C3a(d3>d4>d5).

The height of the protrusion31gradually decreases from the position C1ato the ends of the protrusion31. The relationship between a distance from the position C1aand a decrease in the height of the protrusion31may or may not be a proportional relationship. For example, a portion of the upper edge of the protrusion31may be horizontal.

Flow velocity of the refrigerant at both ends of the flow path in the X-axis direction is slower than flow velocity of the refrigerant at the center of the flow path in the X-axis direction intersecting the flow path direction (the flow direction of the refrigerant). This modification includes a configuration in which the height of the protrusion31decreases from the center of the protrusion31in the X-axis direction to both the ends of the protrusion31in the X-axis direction. Therefore, it is possible to reduce a difference between the flow velocities of the refrigerant in the cooling apparatus1C in the X-axis direction intersecting the flow path direction.

A configuration is described in which, in the X-axis direction intersecting the Y1 direction that is the flow path direction of the refrigerant, the height of the protrusion31decreases from the center of the protrusion31to both ends of the protrusion31. However, the cooling apparatus1C according to this modification is not limited to the configuration. For example, a first portion of the protrusion31may be freely selected in the X-axis direction based on the positions of the supply pipe71and the drain pipe72, and a height of the first portion of the protrusion31may be greater than a height of the other portion of the protrusion31.

In the cooling apparatus1according to the first embodiment, the semiconductor modules50A to50C, which are each an example of the cooling target, are cooled. However, the cooling target is not limited to the semiconductor module. For example, semiconductor elements may be cooled instead of the semiconductor modules50A to50C. In addition, an element other than semiconductor components (semiconductor modules or semiconductor elements) may be cooled as the cooling target.

Although the semiconductor apparatus5according to the first embodiment includes the cooling apparatus1, embodiments according to the disclosure are not limited to this aspect. For example, the semiconductor apparatus5may include the cooling apparatus1A according to the second embodiment or the cooling apparatus1B according to the third embodiment instead of the cooling apparatus1.

DESCRIPTION OF REFERENCE SIGNS