JP2022178699A - cooling structure - Google Patents

Abstract

To provide a resin-made cooling structure which is excellent in cooling efficiency.SOLUTION: A cooling structure 10 has a resin-made flow channel formation member 14 forming a flow channel circulating a refrigerant, a bus bar 26 having a terminal part 28A, a terminal part 28B and a connection part 30 for connecting the terminal part 28A and the terminal part 28B, and a fastening part which is provided on an outer wall surface of the flow channel formation member 14 and fixes the terminal part 28A and the terminal part 28B of the bus bar 26 to the flow channel formation member 14, wherein at least a part of the connection part 30 is brought into contact with the refrigerant through the flow channel formation member 14.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to cooling structures.

A vehicle equipped with a motor, such as a hybrid vehicle or an electric vehicle, is equipped with a driving means for driving the motor. The driving means includes a power module including a plurality of power semiconductors such as IGBTs (Insulated Gate Bipolar Transistors), electronic components such as capacitors, bus bars electrically connecting these electronic components, and the like.
When driving a motor, a large current may flow through a bus bar that joins electronic components such as power semiconductors and capacitors. When a large current flows through the busbar, the drive means heats up due to switching loss, resistance loss, and the like, so it is necessary to efficiently cool the drive means.

As a cooling means for cooling the driving means, a heat sink made of metal such as aluminum or copper is used because of its high thermal conductivity (see, for example, Patent Document 1).

JP 2010-182831 A

However, in order to manufacture a heat sink made of metal, it is necessary to go through complicated manufacturing processes such as extrusion molding, skiving, and crimping. Therefore, metal heat sinks tend to be expensive.
In addition, many man-hours may be required to incorporate a metal heat sink into a cooling object such as a driving means. Therefore, there is a demand for a cooling method with excellent cooling efficiency without using a metal heat sink.

SUMMARY An advantage of some aspects of the present disclosure is to provide a resin-made cooling structure having excellent cooling efficiency.

Specific means for achieving the above object are as follows.
<1> A flow path forming member made of resin that forms a flow path for circulating a coolant;
a busbar having a plurality of terminal portions and a connecting portion connecting the plurality of terminal portions;
a fastening portion provided on an outer wall surface of the flow path forming member for fixing the plurality of terminal portions of the bus bar to the flow path forming member;
A cooling structure in which at least a portion of the connecting portion is in contact with the coolant through the flow path forming member.
<2> the flow path forming member has an insertion groove recessed into the flow path from the outer wall surface side of the flow path forming member;
The cooling structure according to <1>, wherein at least a portion of the connecting portion is inserted into the insertion groove.
<3> The cooling structure according to <2>, wherein one wall surface of the insertion groove has a protrusion that presses at least a part of the connecting portion inserted into the insertion groove against the other wall surface of the insertion groove. .
<4> The cooling structure according to <1>, wherein at least a portion of the connecting portion is in contact with an outer wall of the flow path forming member.
<5> A portion of the outer wall of the flow path forming member that is in contact with the connecting portion has a curved depression, and at least a portion of the connecting portion extends along the curved depression on the outer wall of the flow path forming member. The cooling structure according to <4> in contact with.
<6> The cooling structure according to <5>, wherein the radius of curvature of the curved depression of the outer wall of the flow path forming member is greater than the radius of curvature of a portion of the connecting portion that contacts the curved depression. .
<7> In <4>, a portion of the outer wall of the flow path forming member that contacts the connecting portion is planar, and at least a portion of the connecting portion is planar and contacts the planar portion of the outer wall. A cooling structure as described.
<8> The cooling structure according to <7>, wherein the outer wall of the flow path forming member has a buffer area in a direction in which the planar area of the connecting portion expands when the bus bar thermally expands.
<9> A resin flow path forming member that forms a flow path for circulating the coolant;
a busbar having a plurality of terminal portions and a connecting portion connecting the plurality of terminal portions;
a fastening portion provided on an outer wall surface of the flow path forming member for fixing the plurality of terminal portions of the bus bar to the flow path forming member;
A cooling structure having a structure in which, when the bus bar thermally expands, an area of the connecting portion in contact with the coolant via the flow path forming member increases.

According to one aspect of the present disclosure, it is possible to provide a resin cooling structure with excellent cooling efficiency.

3 is a plan view of the essential parts of the cooling structure 10. FIG. FIG. 2 is a diagram showing a cross section of the cooling structure 10 taken along the line AA in FIG. 1; FIG. 2 is a view showing a BB line end face in FIG. 1 of the cooling structure 10; FIG. 4 is a diagram for explaining a state in which a bus bar 26 in the cooling structure 10 heats up and expands; FIG. 11 is a plan view showing a main part of a modified example of the cooling structure 10; FIG. 5 is a diagram showing an end surface of a flow path 12 of a modified example of the cooling structure 10; 4 is a plan view of a main part of the cooling structure 44; FIG. FIG. 8 is a view showing a CC line cross section in FIG. 7 of the cooling structure 44; FIG. 4 is a diagram for explaining a state in which a bus bar 26 in a cooling structure 44 generates heat and expands; FIG. 11 is a cross-sectional view showing a main part of a modified example of the cooling structure 44; 4 is a cross-sectional view showing the essential parts of the cooling structure 50. FIG.

Hereinafter, embodiments for implementing the present disclosure will be described in detail. However, the present disclosure is not limited to the following embodiments. In the following embodiments, the constituent elements (including element steps and the like) are not essential unless otherwise specified.

<Cooling structure>
A first cooling structure of the present disclosure includes a resin flow path forming member that forms a flow path for circulating a coolant, a bus bar that includes a plurality of terminal portions and a connecting portion that connects the plurality of terminal portions, a fastening portion that is provided on an outer wall surface of the flow path forming member and fixes the plurality of terminal portions of the bus bar to the flow path forming member; It is in contact with the coolant through the forming member.
In the first cooling structure of the present disclosure, since at least a part of the connecting portion that constitutes the busbar is in contact with the coolant through the flow path forming member, the busbar that is heated by energization or the like can be efficiently cooled, and the cooling efficiency is improved. improves.
A second cooling structure of the present disclosure includes a resin flow path forming member that forms a flow path for circulating a coolant, a bus bar that includes a plurality of terminal portions and a connecting portion that connects the plurality of terminal portions, a fastening portion provided on an outer wall surface of the flow path forming member for fixing the plurality of terminal portions of the bus bar to the flow path forming member, wherein when the bus bar thermally expands, the connecting portion The area in contact with the coolant through the flow path forming member of is increased.
In the second cooling structure of the present disclosure, when the busbar thermally expands due to energization or the like, it has a structure in which the area in contact with the refrigerant increases through the flow path forming member of the connecting portion that constitutes the busbar. It becomes possible to efficiently cool the heated bus bar, and the cooling efficiency is improved.
Hereinafter, the first cooling structure and the second cooling structure of the present disclosure may be collectively referred to as the cooling structure of the present disclosure.

In the first cooling structure of the present disclosure, "at least a part of the connecting part is in contact with the refrigerant" means that at least a part of the connecting part is in contact with the coolant through the flow path forming member when the bus bar is generating heat due to energization or the like. means that it is in contact with the refrigerant. When the busbar does not generate heat, the connecting portion may or may not be in contact with the coolant through the flow path forming member.
In the cooling structure according to the present disclosure, the term “connecting portion contacts the coolant “through” the flow path forming member” means that the flow path forming member is interposed between the connecting portion and the coolant. The connecting portion does not come into direct contact with the refrigerant.

The cooling structure of the present disclosure will now be described with reference to the drawings. Note that the sizes of the members in each drawing are conceptual, and the relative relationship between the sizes of the members is not limited to this. In addition, members having substantially the same functions are given the same reference numerals throughout the drawings, and overlapping explanations may be omitted.

(First embodiment)
1 to 3 are diagrams showing the essential parts of the cooling structure 10 according to the first embodiment. FIG. 1 shows a plan view of the essential parts of the cooling structure 10, and FIG. 1, and FIG. 3 shows an end face of the cooling structure 10 taken along line BB in FIG.
The cooling structure 10 includes a flow path forming member 14 made of resin that forms a flow path 12 having a substantially rectangular cross section through which a coolant flows. The flow path 12 includes an upper inner wall 16 corresponding to one inner wall of a pair of opposing inner walls, a lower inner wall 18 corresponding to the other inner wall, and side inner walls 20 connecting the upper inner wall 16 and the lower inner wall 18 . It is configured to be surrounded by side inner walls 22 .

The outer wall surface of the flow path forming member 14 is provided with an insertion groove 24 that is depressed toward the inside of the flow path 12 from the outer wall surface side of the flow path forming member 14 . The longitudinal direction of the insertion groove 24 is along the direction in which the coolant flows in the channel 12 .

The bus bar 26 has a terminal portion 28A, a terminal portion 28B, and a connecting portion 30 connecting the terminal portion 28A and the terminal portion 28B. The connecting part 30 is inserted into the insertion groove 24 and arranged in the flow path 12 , and can come into contact with the coolant flowing through the flow path 12 via the wall surface of the insertion groove 24 that constitutes the flow path forming member 14 . It is made like this.
A clearance is provided between the connecting portion 30 and the wall surface of the insertion groove 24 from the viewpoint of work efficiency when inserting the connecting portion 30 into the insertion groove 24 .
In the cooling structure 10 , a clearance is provided over the entire circumference of the connecting portion 30 so that the connecting portion 30 does not come into contact with the wall surface of the insertion groove 24 . may be in contact with at least a portion of the

A portion of the nut 34A opposite to the side into which the bolt 32A is inserted and a portion of the nut 34B opposite to the side into which the bolt 32B is inserted are provided on the outer wall surface of the flow path forming member 14 .

The terminal portion 28A is fastened and fixed to the outer wall surface of the flow path forming member 14 together with the terminal portion 28C of another bus bar 38 by a fastening portion 36A composed of a bolt 32A and a nut 34A.
The terminal portion 28B is fastened and fixed to the outer wall surface of the flow path forming member 14 together with the terminal portion 28D of the other bus bar 40 by a fastening portion 36B composed of a bolt 32B and a nut 34B.
The busbars 38 and 40 are connected to electronic components (not shown) such as power semiconductors and capacitors.

Here, when a current flows through the busbar 26, the busbar 26 generates heat and expands. Since the terminal portions 28A and 28B of the busbars 26 are fastened to the flow path forming member 14 by the fastening portions 36A and 36B, respectively, when the busbars 26 heat up and expand, the terminal portions 28A and 28B are separated from each other. the distance between them does not change significantly. On the other hand, when the bus bar 26 heats up and expands, as shown in FIG. As a result, the area of the connecting portion 30 that is in contact with the coolant through the flow path forming member 14 increases. Therefore, the cooling efficiency of the connecting portion 30 by the coolant is improved.

FIG. 5 is a plan view showing essential parts of a modification of the cooling structure 10 according to the first embodiment. In the modified example of the first embodiment, one wall surface of the insertion groove 24 has a protrusion 42 that presses at least a part of the connecting part 30 inserted into the insertion groove 24 against the other wall surface of the insertion groove 24. It is
The connection part 30 is pressed against one wall surface of the insertion groove 24 by providing the protrusion 42 on one wall surface of the insertion groove 24 . Therefore, the cooling efficiency of the connecting portion 30 by the coolant is improved.
The protruding portion 42 may extend in a ridge-like shape toward the inside of the flow path 12 from the opening side of the insertion groove 24, or may have a point-like shape.

Also, the connection portion 30 of the bus bar 26 may be embedded in the flow path forming member 14 by insert molding or the like so as to have no clearance.

Also, the end face of the flow path 12 of the cooling structure 10 is not limited to the rectangular shape shown in FIG. good. Further, in order to ensure the flow rate of the coolant, the end face of the flow path 12 has a triangular end face perpendicular to the coolant flow direction of the upper inner wall 16 as shown in FIG. may be provided.

The type of coolant that flows through flow path 12 is not particularly limited. Examples of the refrigerant include liquids such as water and organic solvents, and gases such as air. The water used as the refrigerant may contain components such as antifreeze.

(Second embodiment)
7 and 8 are diagrams showing the essential parts of the cooling structure 44 according to the second embodiment. FIG. 7 shows a plan view of the essential parts of the cooling structure 44, and FIG. 8 shows the cooling structure 44. 7 shows a CC line cross section in FIG. In the cooling structure 44 , at least a portion of the connecting portion 30 is configured to be in contact with the outer wall of the flow path forming member 14 .

In the cooling structure 44, a part of the connecting part 30 is in contact with the outer wall of the flow path forming member 14, so that a part between the fastening part 36A and the fastening part 36B in the flow path 12 is on the side of the connecting part 30. It has a protruding structure 46 that protrudes into. A curved depression 48 is provided at the top of the convex structure 46 .

As shown in FIGS. 7 and 8, the bus bar 26 is flat. As shown in FIG. 8, the central portion of the connecting portion 30 that connects the terminal portion 28A and the terminal portion 28B of the bus bar 26 protrudes toward the outer wall side of the flow path forming member 14, and the top portion thereof is a curved depression. It is in contact with the outer wall of the flow path forming member 14 along 48 .

Here, when a current flows through the busbar 26, the busbar 26 generates heat and expands. Since the terminal portions 28A and 28B of the busbars 26 are fastened to the flow path forming member 14 by the fastening portions 36A and 36B, respectively, when the busbars 26 heat up and expand, the terminal portions 28A and 28B are separated from each other. the distance between them does not change significantly. On the other hand, since the connecting portion 30 protrudes toward the outer wall side of the flow path forming member 14, the bus bar 26 heats up and expands, so that the connecting portion 30 protrudes toward the outer wall side of the flow path forming member 14 by a large amount. Thus, as shown in FIG. 9, the connecting portion 30 comes into contact with the outer wall of the flow path forming member 14 more. As a result, the area of the connecting portion 30 that is in contact with the coolant through the flow path forming member 14 increases. Therefore, the cooling efficiency of the connecting portion 30 by the coolant is improved.

FIG. 10 is a cross-sectional view showing essential parts of a modification of the cooling structure 44 according to the second embodiment. FIG. 10 shows a cross section perpendicular to the coolant flow direction in the flow path 12 of the modified example of the cooling structure 44 and passing through the centers of the bolts 32A and 32B. In the modified example of the cooling structure 44 shown in FIG. 10 , the busbars 26 are arranged along the direction perpendicular to the direction in which the coolant flows in the flow path 12 .
In the modification of the second embodiment, in order to make at least a portion of the connecting portion 30 contact the outer wall of the flow path forming member 14, instead of providing the convex structure 46 in the flow path 12, the fastening portion 36A is provided. A nut 34</b>A and a nut 34</b>B forming a fastening portion 36</b>B are embedded in the outer wall of the flow path forming member 14 . In order to embed the nut 34A in the outer wall of the flow path forming member 14, the width of the flow path forming member 14 is widened in the thickness direction of the flow path forming member 14 from the side inner wall 22 side. Further, in order to embed the nut 34B in the outer wall of the flow path forming member 14, the width of the flow path forming member 14 is widened in the thickness direction of the flow path forming member 14 from the side inner wall 20 side. The portion where the passage forming member 14 is widened toward the outer wall surface side of the passage forming member 14 may be only the portion where the nut 34A and the nut 34B are embedded, or the entire passage forming member 14 may be It may be widened. By embedding the nuts 34A and the nuts 34B in the outer wall of the flow path forming member 14, the height of the cooling structure 44 can be reduced.
Further, by embedding the nuts 34A and 34B in the outer wall of the flow path forming member 14, at least a portion of the connecting portion 30 is in contact with the outer wall of the flow path forming member 14 while maintaining the straight shape of the flow path 12. can be configured. By maintaining the shape of the flow path 12 in a straight line, the flow of the coolant flowing through the flow path 12 is less likely to be blocked, so the flow rate of the coolant increases and the cooling efficiency improves.
In addition, in the modified example of the cooling structure 44 , a curved depression 48 is provided at a portion of the outer wall of the flow path forming member 14 where at least a portion of the connecting portion 30 contacts the outer wall of the flow path forming member 14 . .
As shown in FIG. 10 , the central portion of the connecting portion 30 of the busbar 26 projects toward the outer wall side of the flow path forming member 14 , and the top of the connecting portion 30 extends along a curved depression 48 of the flow path forming member 14 . in contact with the outer wall.

In the second embodiment, the radius of curvature of the curved depression (for example, the depression 48 at the top of the convex structure 46 in FIG. 8) of the outer wall of the flow path forming member 14 contacts the curved depression in the connecting portion 30. It is preferably larger than the radius of curvature of the point. By making the radius of curvature of the curved depression of the outer wall of the flow path forming member 14 larger than the radius of curvature of the portion of the connection portion 30 that contacts the curved depression, when the bus bar 26 thermally expands, the connection portion 30 It becomes possible to increase the contact area with the outer wall of the air conditioner, further improving the cooling efficiency.
The radius of curvature is set in consideration of the type of metal forming the busbar, the amount of heat generated by the busbar, and the like.

(Third embodiment)
FIG. 11 is a cross-sectional view showing a main part of the cooling structure 50 according to the third embodiment, showing a cross section passing through the centers of the bolts 32A and 32B of the cooling structure 50. As shown in FIG. In the cooling structure 50 , at least a portion of the connecting portion 30 is configured to be in contact with the outer wall of the flow path forming member 14 .

In the cooling structure 50, the portion of the outer wall of the flow path forming member 14 that contacts the connecting portion 30 is planar. The connecting portion 30 that constitutes the bus bar 26 in the cooling structure 50 includes a flat portion 52 that protrudes toward the outer wall of the flow path forming member 14 and is in contact with the planar portion of the outer wall, and between the flat portion 52 and the terminal portion 28A. It has an interposed buffer portion 54A and a buffer portion 54B interposed between the flat portion 52 and the terminal portion 28B. The flat portion 52 that constitutes a part of the connecting portion 30 is in contact with the flat portion of the outer wall of the flow path forming member 14 in a flat state.
A buffer region 56A is provided between the base of the fastening portion 36A on the outer wall of the flow path forming member 14 (where the nut 34A is provided on the outer wall surface of the flow path forming member 14) and the flat portion 52. . A buffer region 56B is provided between the base of the fastening portion 36B on the outer wall of the flow path forming member 14 (where the nut 34B is provided on the outer wall surface of the flow path forming member 14) and the flat portion 52. ing.

Here, when a current flows through the busbar 26, the busbar 26 generates heat and expands. In the cooling structure 50, especially the flat portion 52 of the bus bar 26 tends to expand in the direction of the arrow in FIG. Even if the flat portion 52 extends in the direction of the arrow in FIG. Extension of 52 is not inhibited. Therefore, the flat portion 52 is prevented from separating from the outer wall of the flow path forming member 14, and the cooling efficiency of the coolant is improved.
A buffer portion 54A is provided between the flat portion 52 and the terminal portion 28A, and a buffer portion 54B is provided between the flat portion 52 and the terminal portion 28B. The strain applied to the terminal portions 28A and 28B is reduced even when the terminal portions 28A and 28B are stretched in the direction of the arrow.

As the bus bar 26 used in the cooling structure 50, for example, there is a shape indicated by a chain double-dashed line in FIG. In bus bar 26 indicated by a two-dot chain line in FIG. 11 , flat portion 52 protrudes in a curved shape toward the outer wall of flow path forming member 14 . Since the flat portion 52 protrudes in a curved shape, when the bus bar 26 is fastened to the cooling structure 50 , the flat portion 52 is easily brought into close contact with the planar portion of the outer wall of the flow path forming member 14 that is in contact with the connecting portion 30 . .

(Manufacturing method of flow path forming member)
The flow path forming member 14 may be manufactured by any method such as an injection molding method, a die slide injection molding method, a blow molding method, a compression molding method, a transfer molding method, an extrusion molding method, and a cast molding method. Ordinary molding methods for resin moldings such as the above can be employed. Note that the die-slide injection molding method is preferable because high positional accuracy may be required for manufacturing the cooling structure.
Also, the portion of the flow path forming member where the nut is provided may be manufactured separately by an insert molding method.

The type of resin forming the flow path forming member 14 is not particularly limited. Resins include polyethylene resins, polypropylene resins (PP), composite polypropylene resins (PPC), polyphenylene sulfide resins (PPS), polyphthalamide resins (PPA), polybutylene terephthalate resins (PBT), epoxy resins, phenolic resins, polystyrene resins, polyethylene terephthalate resins, polyvinyl alcohol resins, vinyl chloride resins, ionomer resins, polyamide resins, acrylonitrile-butadiene-styrene copolymer resins (ABS), polycarbonate resins, etc. is mentioned.

The resin forming the flow path forming member 14 may contain an inorganic filler. Inorganic fillers include, for example, silica, alumina, zircon, magnesium oxide, calcium silicate, calcium carbonate, potassium titanate, silicon carbide, silicon nitride, boron nitride, beryllia and zirconia. Furthermore, examples of inorganic fillers having a flame retardant effect include aluminum hydroxide and zinc borate.

(Use of cooling structure)
INDUSTRIAL APPLICABILITY The cooling structure of the present disclosure is effective for cooling a power module including a plurality of power semiconductors and a bus bar that electrically joins electronic components such as a capacitor in a vehicle equipped with a motor such as a hybrid vehicle or an electric vehicle.

10, 44, 50 cooling structure 12 channel 14 channel forming member 16 upper inner wall 18 lower inner wall 20, 22 side inner wall 24 insertion grooves 26, 38, 40 bus bar 28A, 28B, 28C, 28D terminal portion 30 connecting portion 32A , 32B bolts 34A, 34B nuts 36A, 36B fastening portion 42 protrusion 46 convex structure 48 depression 52 flat portions 54A, 54B buffer portions 56A, 56B buffer region

Claims (9)

a resin flow path forming member that forms a flow path through which the coolant flows;
a busbar having a plurality of terminal portions and a connecting portion connecting the plurality of terminal portions;
a fastening portion provided on an outer wall surface of the flow path forming member for fixing the plurality of terminal portions of the bus bar to the flow path forming member;
A cooling structure in which at least a portion of the connecting portion is in contact with the coolant through the flow path forming member. The flow path forming member has an insertion groove recessed into the flow path from the outer wall surface side of the flow path forming member,
2. The cooling structure according to claim 1, wherein at least a portion of said connecting portion is inserted into said insertion groove. 3. The cooling structure according to claim 2, wherein one wall surface of said insertion groove has a protrusion that presses at least a portion of said connecting portion inserted into said insertion groove against the other wall surface of said insertion groove. 2. The cooling structure according to claim 1, wherein at least part of said connecting portion is in contact with an outer wall of said flow path forming member. A portion of the outer wall of the flow path forming member that contacts the connecting portion has a curved recess, and at least a portion of the connecting portion contacts the outer wall of the flow channel forming member along the curved recess. Item 5. The cooling structure according to item 4. 6. The cooling structure according to claim 5, wherein the radius of curvature of the curved depression of the outer wall of the flow path forming member is larger than the radius of curvature of a portion of the connecting portion that contacts the curved depression. 5. The cooling device according to claim 4, wherein a portion of the outer wall of the flow path forming member that contacts the connecting portion is planar, and at least a portion of the connecting portion is planar and contacts the planar portion of the outer wall. Structure. 8. The cooling structure according to claim 7, wherein the outer wall of the flow path forming member has a buffer area in a direction in which the planar area of the connecting portion expands when the busbar thermally expands. a resin flow path forming member that forms a flow path through which the coolant flows;
a busbar having a plurality of terminal portions and a connecting portion connecting the plurality of terminal portions;
a fastening portion provided on an outer wall surface of the flow path forming member for fixing the plurality of terminal portions of the bus bar to the flow path forming member;
A cooling structure having a structure in which, when the bus bar thermally expands, an area of the connecting portion in contact with the coolant via the flow path forming member increases.

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