Power Conversion Device

Abstract

To provide a power conversion device with excellent watertightness by preventing sealing member entrapment.SOLUTION: A power conversion device comprises: a semiconductor module with built-in semiconductor elements; a flat tube 4a through which the cooling liquid flows; and a header 5b attached to the flat tube 4a and holding the flat tube 4a in thermal contact with the semiconductor module. The header 5b has a seal mating hole 20 into which an end portion of the flat tube 4a is inserted, a seal member 6 for watertightly sealing a gap between an outer circumference of the flat tube 4a and an inner circumference of the seal mating hole 20, and a cooling liquid flow path connected to the seal mating hole 20. The seal member 6 is attached to the seal mating hole 20 and has convex portions 6c and 6d to seal the gap watertight, and a protrusion 6b contacting the header 5b in the direction of flat tube insertion at the opening side of the seal mating hole 20.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to a power conversion device. [Background technology]

[0002] In electric vehicles and hybrid vehicles, miniaturization and cost reduction of the components installed are important. Power conversion devices, which convert direct current from the battery into alternating current for the motor, are no exception, and miniaturization and cost reduction are required. As a result, heat generation density increases, so cooling performance needs to be improved.

[0003] Among the electronic components constituting a power conversion device, the power module generates the greatest amount of heat. For this reason, a method for cooling a power module is known in which a tubular cooler through which a cooling liquid flows is provided on the heat dissipation surface of the power module (see, for example, Patent Document 1). In the technology described in Patent Document 1, a flat tubular body is used to increase the contact area. In the technology described in Patent Document 1, an elastic seal ring is attached to the end of the tubular body and inserted into a pipe insertion and holding portion of the cooling liquid supply and discharge portion, thereby sealing the gap between the flat tubular body and the cooling liquid supply and discharge portion. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-76644 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when the tubular body through which the coolant flows is a flat tube, the portion that makes linear contact with the sealing member is long, and when the sealing member is attached to the end of the tubular body and inserted into the tube insertion holding section, or when the end of the tubular body is inserted into the tube insertion holding section provided with the sealing member, there is a risk that the sealing member will become entangled. [Means for solving the problem]

[0006] A power conversion device according to an aspect of the present invention includes a semiconductor module incorporating a semiconductor element, a flat tube through which a coolant flows, and a pair of headers attached to both ends of the flat tube to hold the flat tube in thermal contact with the semiconductor module, the header having an insertion hole into which the end of the flat tube is inserted, a seal member for watertightly sealing a gap between an outer circumferential surface of the flat tube and an inner circumferential surface of the insertion hole, and a coolant flow path communicating with the insertion hole, the seal member being attached to the insertion hole and having a sealing portion for watertightly sealing the gap, and an abutting portion that abuts against the header on the opening side of the insertion hole in the flat tube insertion direction. a clamped portion that is clamped between the tip of the flat tube inserted into the insertion hole and the bottom of the insertion hole; With The sealing member has a first tapered surface formed in a region facing the bottom of the insertion hole, and the insertion hole has a second tapered surface formed opposite the first tapered surface. . [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a power converter that is excellent in watertightness by preventing the sealing member from being caught in the power converter. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is an exploded perspective view of the power conversion device. [Figure 2] FIG. 2 is a cross-sectional view of the power converter as viewed from the direction A in FIG. [Figure 3] FIG. 3 is a cross-sectional view taken along line BB in FIG. [Figure 4] FIG. 4 is an enlarged view of the area surrounded by the dashed line C in FIG. [Figure 5] FIG. 5 is a cross-sectional view showing the structure of the upper header. [Figure 6] FIG. 6 is a view taken along the arrow D in FIG. [Figure 7] FIG. 7 is a cross-sectional view showing the structure of the lower header. [Figure 8] FIG. 8 is a cross-sectional view showing a state before the sealing member is inserted into the flat tube. [Figure 9] FIG. 9 is a cross-sectional view showing a state in which flat tubes are inserted into the header. [Figure 10]FIG. 10 is a diagram showing the first modification. [Figure 11] FIG. 11 is a diagram illustrating the second embodiment. [Figure 12] FIG. 12 is a diagram illustrating the third embodiment. [Figure 13] FIG. 13 is a diagram illustrating the fourth embodiment. [Figure 14] FIG. 14 is a diagram illustrating the fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The following description and drawings are examples for explaining the present invention, and appropriate omissions and simplifications have been made for clarity of explanation. Furthermore, in the following description, identical or similar elements and processes are given the same reference numerals, and duplicate explanations may be omitted. Note that the content described below merely shows an example of an embodiment of the present invention, and the present invention is not limited to the following embodiment, and can be implemented in various other forms.

[0010] (First embodiment) Fig. 1 is an exploded perspective view of a power conversion device. The power conversion device 1 includes a power module 2. In the example shown in Fig. 1, three power modules 2 are included, but the number of power modules 2 is not limited to three. In this embodiment, xyz coordinate axes are set as shown in Fig. 1. That is, a plurality of power modules 2 are arranged in the x direction, and the thickness direction of the power modules 2 is set as the z direction.

[0011] Each power module 2 has an upper arm circuit and a lower arm circuit of an inverter inside, which respectively constitute the U phase, V phase, and W phase. Heat dissipation surfaces are provided on both the front and back sides of the power module 2, and the areas other than the heat dissipation surfaces are molded with a sealing material such as resin. Flat tubes 4a, 4b that function as coolers are provided on both the front and back sides of each power module 2. The flat tubes 4a, 4b are in thermal contact with the heat dissipation surfaces of the power module 2 via a TIM (Thermal Interface Material) 3. The TIM 3 is, for example, applied to both the front and back sides of the power module 2.

[0012] Headers 5a and 5b for supplying and discharging the coolant are provided at both ends of the flat tube 4a, and headers 5c and 5d for supplying and discharging the coolant are provided at both ends of the flat tube 4b. Sealing members 6 for preventing leakage of the coolant are provided at the connections between the flat tube 4a and the headers 5a and 5b, and at the connections between the flat tube 4b and the headers 5c and 5d. The sealing members 6 are made of an elastic material such as rubber.

[0013] FIG. 2 is a diagram showing the power converter 1 with the various components assembled, and is a cross-sectional view of the power converter 1 as viewed from direction A in FIG. 1. The end of the upper flat tube 4a is inserted into the headers 5a and 5b on the upper side of the figure, which have sealing members 6 attached. Similarly, the end of the lower flat tube 4b is inserted into the headers 5c and 5d on the lower side of the figure, which also have sealing members 6 attached. The power module 2, which has TIM3 applied to both its front and back surfaces, is held in place by being sandwiched between the flat tubes 4a and 4b.

[0014] FIG. 3 is a cross-sectional view taken along the line B-B of FIG. 2. As shown in FIG. 3, in order to improve the adhesion of the TIM 3, the flat tubes 4a and the base plate 7 are sandwiched between leaf springs 12, so that the upper flat tube 4a is pressed against the power module 2, and the power module 2 is pressed against the lower flat tube 4b. A plurality of flow paths 41 are formed inside each of the flat tubes 4a and 4b in their longitudinal direction. The headers 5b and 5d are integrally fixed to the base plate 7 by threading bolts 19 that pass through the upper header 5b and the lower header 5d into threaded holes 18 formed in the base plate 7. Although not shown, the headers 5a and 5c shown in FIG. 1 are also fixed to the base plate 7 in a similar manner. The base plate 7 is formed with a coolant supply port 10 and a coolant discharge port 11. Although not shown, the supply port 10 and the discharge port 11 are connected to coolant flow paths (not shown) on the system side.

[0015] FIG. 4 is an enlarged view of the area surrounded by dashed line C in FIG. 2. The headers 5b and 5d are connected so as to be stacked one on top of the other. The header 5b has an insertion hole 14 into which the shaft portion 15 formed on the upper surface of the header 5d is inserted. The flow path 41 of the flat tube 4a connected to the header 5b communicates with the insertion hole 14 via the communication hole 21 of the header 5b. The shaft portion 15 formed on the upper surface of the header 5d is inserted into the insertion hole 14. As shown in FIG. 1, the shaft portion 15 is a ring-shaped protrusion that is elongated in the y direction. The outer peripheral surface of the shaft portion 15 has a seal groove 16 into which an O-ring 17 is fitted. The O-ring 17 maintains the watertightness of the connection between the insertion hole 14 and the shaft portion 15.

[0016] A through-hole 155 is formed in the shaft portion 15, penetrating the header 5b in the vertical direction (z direction) in the figure. The flow paths 41 of the flat tubes 4b connected to the header 5d communicate with the through-hole 155 via the communication holes 21 of the header 5d. The through-hole 155 communicates with the discharge port 11 of the base plate 7 to which the header 5d is fixed. A seal groove 8 is provided on the upper surface of the base plate 7, and an O-ring 9 is provided in the seal groove 8. The O-ring 9 maintains the watertightness of the connection between the header 5d and the base plate 7.

[0017] Although not explained further, as shown in the cross-sectional view of Figure 2, the structure of headers 5a and 5c and the connection structure between header 5c and base plate 7 are similar to the structure of headers 5b and 5d described above and the connection structure between header 5d and base plate 7.

[0018] The coolant supplied to the supply port 10 of the base plate 7 flows into the through hole 155 of the header 5c, flows into the flow paths 41 of the flat tubes 4b via the communication hole 21, and also flows into the flow paths 41 of the flat tubes 4a via the insertion hole 14 and communication hole 21 of the header 5a. The coolant that flows through the flat tubes 4a from the header 5a side to the header 5b side flows into the through hole 155 of the header 5d via the communication hole 21 and insertion hole 14 of the header 5b. On the other hand, the coolant that flows through the flat tubes 4b from the header 5c side to the header 5d side flows into the through hole 155 via the communication hole 21 of the header 5d. The coolant that flows into the through hole 155 is then discharged from the discharge port 11 of the base plate 7.

[0019] FIG. 5 is a cross-sectional view showing the structure of the upper header 5b, taken from the direction A in FIG. 1. FIG. 6 is a view taken from the direction D in FIG. 5. The header 5b is formed with a seal fitting hole 20 into which the seal member 6 is attached, an insertion hole 14 into which the shaft portion 15 of the header 5d is inserted, a communication hole 21 connecting the seal fitting hole 20 and the insertion hole 14, and a through hole 13 for bolt fastening. The seal fitting hole 20 is provided with a stepped portion 20a, a positioning portion 20b, and an inner circumferential surface 20c. The communication hole 21 is formed in the positioning portion 20b, which is the bottom of the seal fitting hole 20. As shown in FIG. 6, the cross-sectional shapes of the stepped portion 20a, the inner circumferential surface 20c, and the communication hole 21 are oval shapes that are long in the y direction.

[0020] 7 is a cross-sectional view showing the structure of the lower header 5d as viewed from direction A in FIG. 1. As in the case of header 5b, header 5d is also formed with a seal fitting hole 20 into which a seal member 6 is attached. The shape of the seal fitting hole 20 is the same as that of the seal fitting hole 20 of header 5b, and includes a stepped portion 20a, a positioning portion 20b, and an inner circumferential surface 20c. A shaft portion 15 is formed on the top surface of header 5d in the figure.

[0021] 1 and 7, the cross-sectional shape (outer peripheral surface shape) of shaft portion 15 on a plane parallel to the xy plane is an ellipse that is long in the y direction, and a seal groove 16 is formed around the outer peripheral surface of shaft portion 15. A through-hole 155 that functions as a coolant flow path is formed so as to penetrate the shaft portion 15 portion of header 5d from top to bottom in the figure. The cross-sectional shape (outer peripheral surface shape) of through-hole 155 on a plane parallel to the xy plane is also an ellipse that is long in the y direction, and through-hole 155 communicates with seal fitting hole 20 via communication hole 21.

[0022] FIG. 8 is a diagram showing the state of the seal member 6 attached to the header 5b before the flat tubes 4a are inserted. The seal member 6 is attached to the seal fitting hole 20 of the header 5b. A presser plate 22 is provided at the opening of the seal fitting hole 20 into which the seal member 6 is attached. The presser plate 22 is fixed to the header 5b with bolts 23. The presser plate 22 has a through hole 230 through which the flat tube 4a is inserted. The seal member 6 is an elastic seal including a ring portion 6a that is an oval ring-shaped columnar body and a protrusion 6b that protrudes radially outward from the ring portion 6a. The protrusion 6b is formed in a flange shape that surrounds the ring portion 6a. The ring portion 6a also has a protrusion 6c formed around the outer circumferential surface and a protrusion 6d formed around the inner circumferential surface.

[0023] The size of the opening surrounded by the apex of the convex portion 6d formed on the inner peripheral surface is set smaller than the cross-sectional size of the flat tube 4a. Because the sealing member 6 is sandwiched between the positioning portion 20b and the pressing plate 22, when the flat tube 4a is inserted into the header 5b in the positive x direction as shown by the arrow, the ring portion 6a is forced outward.

[0024] FIG. 9 is a diagram showing the state in which the flat tube 4a is inserted into the header 5b. The flat tube 4a is inserted until its tip abuts the positioning portion 20b of the seal fitting hole 20. In the state shown in FIG. 9, the convex portion 6d of the seal member 6 abuts against the outer peripheral surface of the flat tube 4a, and the portion where the convex portions 6c and 6d are formed is mainly compressed and deformed in the radial direction. The thickness of the portion of the seal member 6 where the convex portions 6c and 6d are formed is compressed by approximately 10 to 40% over the entire circumference. The outer peripheral surface of the flat tube 4a receives a reaction force from the convex portion 6d to the compressive force all around, and the flat tube 4a is positioned at a position where the upper and lower reaction forces are balanced. The compressed convex portion 6d comes into close contact with the outer peripheral surface of the flat tube 4a, thereby maintaining watertightness between the flat tube 4a and the seal member 6. Furthermore, the compressed convex portion 6c comes into close contact with the inner peripheral surface 20c of the seal fitting hole 20, thereby maintaining watertightness between the seal member 6 and the header 5b.

[0025] As described above, the seal member 6 is compressed when the flat tube is inserted, and therefore, when the flat tube 4a is inserted, the protrusion 6d is subjected to a frictional force in the direction in which the flat tube 4a is inserted (the x-positive direction). This frictional force causes the end face of the ring portion 6a in the x-positive direction to abut against the positioning portion 20b in the insertion direction of the flat tube 4a. Furthermore, the protrusion 6b protruding from the outer periphery of the ring portion 6a abuts against the bottom of the step portion 20a in the insertion direction of the flat tube 4a. Therefore, when the flat tube 4a is inserted, the protrusion 6d of the seal member 6 is subjected to a frictional force in the insertion direction (the x-positive direction), but in response, the seal member 6 is subjected to a reaction force in the x-negative direction from the bottom surface of the step portion 20a of the seal fitting hole 20 and the positioning portion 20b.

[0026] When the flat tube 4a is inserted, if the protrusion 6d experiences a frictional force in the insertion direction of the flat tube 4a (to the right in the figure), the sealing member 6 will be subjected to a force that rolls the sealing member 6 in the insertion direction or a force that crushes the sealing member 6. However, the protrusion 6b receives a reaction force from the bottom surface of the step portion 20a, and the end face of the ring portion 6a receives a reaction force from the positioning portion 20b, thereby preventing the sealing member 6 from being displaced in the flat tube insertion direction or being rolled up. Note that, while roll-up of the sealing member 6 is prevented by at least the protrusion 6b abutting against the bottom surface of the step portion 20a, by configuring the ring portion 6a to abut against the positioning portion 20b, roll-up can be more reliably prevented. As a result, assembly can be improved.

[0027] Furthermore, the provision of the retaining plate 22 has the following effect. When coolant is allowed to flow in the state shown in FIG. 9, the seal member 6 is subjected to hydraulic pressure directed to the left in the figure. If the retaining plate 22 were not provided, the seal member 6 could be prevented from coming off the seal fitting hole 20 if the static friction force at the protrusions 6c, 6d of the seal member 6 was greater than the hydraulic pressure, but if the hydraulic pressure was greater than the static friction force, the seal member 6 could not be prevented from coming off. On the other hand, the provision of the retaining plate 22 can prevent the seal member 6 from coming off the seal fitting hole 20 due to the hydraulic pressure of the coolant.

[0028] The seal member 6 may have a configuration in which the protrusions 6c and 6d are not provided on the ring portion 6a, as in Modification 1 shown in FIG. 10 . In this case, when the flat tube is inserted, the ring portion 6a is compressed radially, so that the inner circumferential surface of the ring portion 6a comes into close contact with the outer circumferential surface of the flat tube 4a, and the outer circumferential surface of the ring portion 6a comes into close contact with the inner circumferential surface 20c of the seal fitting hole 20, thereby maintaining watertightness. However, in the case of FIG. 9 , by providing the protrusions 6c and 6d on the ring portion 6a of the seal member 6, the compressive force generated when the seal member 6 is compressed radially by inserting the flat tube 4a is concentrated on the protrusions 6c and 6d. As a result, the reaction force of the compressive force acting on the outer circumferential surface of the flat tube 4a and the inner circumferential surface 20c of the seal fitting hole 20 is increased, further improving watertightness.

[0029] Furthermore, because the sealing member 6 is made of an elastic material such as rubber, when the sealing member 6 is compressed radially by inserting the flat tube, it also tends to stretch in the left-right direction in Figure 9. However, this stretching is restricted by the pressing plate 22, so the radial compressive force in the areas where the protrusions 6c and 6d are provided becomes greater, improving watertightness.

[0030] 2 and 4, the shaft portions 15 of the lower headers 5c and 5d are inserted into the insertion holes 14 of the upper headers 5b and 5d, and watertightness is maintained by O-rings 17. As a result, even if there is variation in the thickness dimension (dimension in the z direction) of the power modules 2 and TIM 3, the dimensional variation can be absorbed by the amount of insertion of the shaft portions 15. Furthermore, because the flat tubes 4a and 4b are held by the elastic seal member 6, displacement due to vibration when mounted on a vehicle can be absorbed, and stress applied to the flat tubes 4a and 4b and the headers 5a to 5d can be alleviated.

[0031] In this embodiment, the retainer plate 22 is fixed by the bolts 23, but it may be fixed by a joining method such as welding.

[0032] (Second embodiment) FIG. 11 is a diagram illustrating a second embodiment and, similar to FIG. 9 , is a cross-sectional view of the header 5b. In the second embodiment, instead of the retaining plate 22 of FIG. 9 , an inner circumferential projection 6e is provided on the seal member 6 to prevent the seal member 6 from being detached due to hydraulic pressure. This inner circumferential projection 6e may be formed in a ring shape around the entire inner circumferential surface of the ring portion 6a, or multiple inner circumferential projections 6e may be formed spaced apart around the entire circumference. The tip of the flat tube 4a inserted into the seal member 6 abuts against the inner circumferential projection 6e protruding inward from the ring portion 6a. As a result, the inner circumferential projection 6e is clamped between the tip of the flat tube 4a and the positioning portion 20b of the seal fitting hole 20. Although not described further, the seal fitting holes 20 and seal members 6 of the headers 5a, 5c, and 5d have the same configuration as the seal fitting holes 20 and seal member 6 of the header 5b.

[0033] In the second embodiment, watertightness is also maintained by the convex portions 6c and 6d of the seal member 6. Furthermore, the protrusion 6b abuts against the bottom of the step portion 20a, preventing the seal member 6 from being caught when the flat tube 4a is inserted into the seal member 6. Furthermore, in the second embodiment, when hydraulic pressure is applied, the tip of the flat tube 4a abuts against the inner peripheral convex portion 6e, causing the seal member 6 to receive a reaction force in the right direction in the figure from the tip of the upper flat tube 4a, preventing it from coming off the seal fitting hole 20 due to hydraulic pressure. Furthermore, because there is no need to provide an additional part for preventing separation, such as the retaining plate 22, the number of parts can be reduced and assembly is improved.

[0034] (Third embodiment) FIG. 12 is a diagram illustrating a third embodiment and, similar to the configuration of FIG. 9, is a cross-sectional view of a header 5b. In comparison with the configuration of FIG. 9, the third embodiment eliminates the retaining plate 22 shown in FIG. 9 by forming a protruding portion 50 that protrudes inward at the opening of the seal fitting hole 20 of the header 5b. The seal fitting hole 20 includes a positioning portion 20b against which the ring portion 6a abuts, an inner peripheral surface 20c against which the protruding portion 6c is closely attached, and a groove portion 20d in which the protruding portion 6b is disposed. In the example shown in FIG. 12, the protruding portion 50 is formed in a ring shape at the opening of the seal fitting hole 20. However, multiple protruding portions 50 may be spaced apart and arranged in a ring shape. When the seal member 6 is inserted into the seal fitting hole 20, the seal member 6 is deformed and inserted into the seal fitting hole 20. Although not described further, the headers 5a, 5c, and 5d also have the same seal fitting holes 20, seal members 6, and protruding portions 50 as those of the header 5b.

[0035] In the third embodiment, when a force in the negative x direction due to hydraulic pressure is applied to the seal member 6, the seal member 6 receives a reaction force in the positive x direction from the protruding portion 50. As a result, it is possible to prevent the seal member 6 from coming off the seal fitting hole 20 due to hydraulic pressure. Furthermore, since there is no need to provide an additional part for preventing coming off, such as the retaining plate 22, the number of parts can be reduced and assembly is improved. Note that if it is difficult to form the protruding portion 50 and the groove portion 20d by machining, it is possible to use three-dimensional molding or to form the opening edge of the seal fitting hole 20 by plastic deformation processing or the like.

[0036] (Fourth embodiment) FIG. 13 is a diagram illustrating the fourth embodiment, and is a cross-sectional view of the header 5b, similar to FIG. 9. A step 40 is formed on the outer peripheral surface of the flat tube 4a, and an insertion portion 42 distal to the step is inserted into the seal member 6. The step 40 protrudes from the outer peripheral surface of the insertion portion 42 and abuts against an end face 60 of the seal member 6, i.e., the end face 60 on the opening side of the seal fitting hole 20. The step 40 is formed by, for example, cutting after the flat tube 4a is extrusion-molded. Although not described further, the headers 5a, 5c, and 5d also have the step 40 and the insertion portion 42 in the end regions of the flat tubes 4a and 4b, similar to the header 5b.

[0037] In the fourth embodiment, when a force in the negative x direction due to hydraulic pressure is applied to the seal member 6, the seal member 6 receives a reaction force in the positive x direction from the step 40 of the flat tube 4a. As a result, it is possible to prevent the seal member 6 from coming off the seal fitting hole 20 due to hydraulic pressure. In the fourth embodiment as well, by providing the step 40, there is no need to provide an additional part for preventing coming off, such as the retaining plate 22, which reduces the number of parts and improves assembly.

[0038] (Fifth embodiment) FIG. 14 is a diagram illustrating the fifth embodiment, and is a cross-sectional view of the header 5b, similar to FIG. 9. The seal member 6 has tapered surfaces 61 formed at the outer circumferential corners of the ring portion 6a. These tapered surfaces 61 are provided to improve the workability of the seal member 6. Meanwhile, a tapered surface 200 is also formed on the bottom side of the seal fitting hole 20, in a position opposite the tapered surface 61. Although not described here, the headers 5a, 5c, and 5d also have tapered surfaces 61 of the seal member 6 and tapered surfaces 200 of the seal fitting holes 20, similar to the header 5b.

[0039] When the flat tube 4a is inserted into the seal member 6, the seal member 6 is compressed outward and pressed against the positioning portion 20b. In this case, as shown in Fig. 14, by forming a tapered surface 200 in the seal fitting hole 20 so as to face the tapered surface 61 of the seal member 6, the tapered surface 61 of the seal member 6 receives a reaction force from the tapered surface 200. By receiving such a reaction force, the seal member 6 is held at the end of the flat tube 4a, and it is possible to prevent the seal member 6 from coming off the seal fitting hole 20 due to the influence of the hydraulic pressure.

[0040] According to the embodiment and the modified example of the present invention described above, the following advantageous effects can be achieved.

[0041] 2, 10, etc., the power converter 1 includes a power module 2 incorporating a semiconductor device, a flat tube 4a through which a coolant flows, and a pair of headers 5a, 5b attached to both ends of the flat tube 4a to hold the flat tube 4a in thermal contact with the power module. The headers 5a, 5b each have a seal fitting hole 20 into which the end of the flat tube 4a is inserted, a seal member 6 for watertightly sealing the gap between the outer circumferential surface of the flat tube 4a and the inner circumferential surface of the seal fitting hole 20, and a communication hole 21 and an insertion hole 14 as a coolant flow path communicating with the seal fitting hole 20. The seal member 6 is attached to the seal fitting hole 20 and has a ring portion 6a for watertightly sealing the gap between the outer circumferential surface of the flat tube 4a and the inner circumferential surface of the seal fitting hole 20, and a protrusion 6b that abuts against the headers 5a, 5b on the opening side of the seal fitting hole 20 in the flat tube insertion direction.

[0042] 10, the protrusion 6b of the sealing member 6 abuts against the bottom surface of the step 20a formed in the header 5a, so when the flat tube 4a is inserted into the ring portion 6a of the sealing member 6, the protrusion 6b receives a reaction force from the bottom surface of the step 20a in the direction opposite to the insertion direction. As a result, it is possible to prevent the sealing member 6 from being displaced or caught in the flat tube insertion direction.

[0043] (C2) In (C1) above, a blocking portion is further provided that abuts against the seal member 6 attached to the seal fitting hole 20 and prevents movement toward the opening of the seal fitting hole 20. For example, as shown in FIG. 10, a pressing plate 22 as a blocking portion is fixed to the header 5b and abuts against the opening-side end face of the seal member 6. By providing the pressing plate 22 (blocking portion), it is possible to prevent the seal member 6 from coming off the seal fitting hole 20 due to the hydraulic pressure of the coolant.

[0044] (C3) In (C2) above, as shown in Figure 11 etc., the preventing portion is the tip of the flat tube 4a inserted into the seal fitting hole 20, and the seal member 6 has an inner circumferential convex portion 6e that is sandwiched between the tip of the flat tube 4a and the positioning portion 20b that is the bottom of the seal fitting hole 20. By sandwiching the inner circumferential convex portion 6e between the flat tube tip and the positioning portion 20b, it is possible to prevent the seal member 6 from coming off the seal fitting hole 20 when hydraulic pressure is applied.

[0045] (C4) In (C2) above, as shown in Figure 13 etc., the blocking portion is a step 40 formed on the outer peripheral surface of the flat tube 4a, and the step 40 is formed so as to protrude from the outer peripheral surface of the insertion portion 42 of the flat tube 4a inserted into the seal fitting hole 20, and abuts against the opening side end face of the seal member 6. The step 40 abutting against the opening side end face of the seal member 6 can prevent the seal member 6 from coming off the seal fitting hole 20 when hydraulic pressure is applied.

[0046] (C5) In (C2) above, as shown in Figure 12 etc., the preventing portion is a protruding portion 50 formed on the header 5b that protrudes toward the opening side of the seal fitting hole 20, and by abutting against the end face of the seal member 6 attached to the seal fitting hole 20, it prevents the seal member 6 from coming off the seal fitting hole 20 when hydraulic pressure is applied.

[0047] 8, 9, etc., in (C1) or (C2) above, the seal member 6 has a ring portion 6a that surrounds the outer periphery of the flat tube 4a, a protrusion 6c that serves as a first sealing portion and that protrudes from the outer periphery of the ring portion 6a, a protrusion 6d that serves as a second sealing portion and that protrudes from the inner periphery of the ring portion 6a, and a protrusion 6b that serves as an abutment portion and that protrudes from the outer periphery of the ring portion 6a. Because the sealing portions are the protrusions 6c and 6d that protrude from the inner and outer periphery of the ring portion 6a, the compressive force generated when the flat tube 4a is inserted into the seal member 6 is concentrated on the protrusions 6c and 6d, and the protrusions 6c and 6d can improve watertightness.

[0048] (C7) In (C1) or (C2) above, as shown in Figures 1 to 4, etc., it has a first flat tube 4b and a second flat tube 4a arranged to sandwich the power module 2, and each of the pair of headers has a first header 5d (5c) attached to the end of the first flat tube 4b and a second header 5b (5a) attached to the end of the second flat tube 4a and stacked on the first header 5d (5c), the first header 5d (5c) has a through hole 155 formed therein that communicates with the cooling flow path of the first header 5d (5c), an O-ring 17 is attached to the outer periphery, and a shaft portion 15 is provided that protrudes in the stacking direction, and the second header 5b (5a) has an insertion hole 14 that communicates with the cooling flow path of the second header 5b (5a) and into which the shaft portion 15 is inserted in the stacking direction.

[0049] In this way, the shaft portion 15 of the header 5d is inserted into the insertion hole 14 of the header 5b in the stacking direction, so even if there is variation in the thickness dimension (dimension in the z direction) of the power module 2, the dimensional variation can be absorbed by the amount of insertion of the shaft portion 15, and watertightness is ensured by the O-ring 17.

[0050] (C8) In (C3) above, as shown in FIG. 14 etc., the seal member 6 is formed with a first tapered surface 61 in an area facing the positioning portion 20b, which is the bottom of the seal fitting hole 20, and the seal fitting hole 20 is formed with a second tapered surface 200 facing the first tapered surface 61. Therefore, when the flat tube 4a is inserted into the seal member 6, the seal member 6 is pressed against the positioning portion 20b, and the tapered surface 61 of the seal member 6 receives a reaction force from the tapered surface 200. This reaction force holds the seal member 6 at the end of the flat tube 4a, making it possible to prevent the seal member 6 from coming off the seal fitting hole 20 due to the influence of hydraulic pressure.

[0051] The above-described embodiments and various modifications are merely examples, and the present invention is not limited to these details as long as the features of the invention are not impaired. Furthermore, although various embodiments and modifications have been described above, the present invention is not limited to these details. Other aspects conceivable within the scope of the technical idea of ​​the present invention are also included within the scope of the present invention.

[0052] For example, in the above-described embodiment, the power conversion device 1 is configured such that flat tubes are arranged on both the front and back sides of the power module 2, but in a configuration in which there is no heat dissipation surface on one side of the power module 2, flat tubes are provided only on the side of that heat dissipation surface.

[0053] Furthermore, the present invention is applicable not only to electric vehicles or hybrid vehicles, but also to power conversion devices for moving objects such as railway vehicles, aircraft, and ships. [Explanation of symbols]

[0054] 1...power conversion device, 2...power module, 4a, 4b...flat tube, 5a to 5c...header, 6...seal member, 6a...ring portion, 6b...protrusion, 6c, 6d...convex portion, 6e...inner peripheral convex portion, 9, 17...O-ring, 14...insertion hole, 15...shaft portion, 20...seal fitting hole, 20a...step portion, 20b...positioning portion, 20c...inner peripheral surface, 20d...groove portion, 21...communicating hole, 22...holding plate, 40...step, 42...insertion portion, 50...extending portion, 61, 200...tapered surface, 155...through hole

Claims

1. a semiconductor module incorporating a semiconductor element; A flat tube through which a coolant flows; a pair of headers attached to both ends of the flat tube, respectively, to hold the flat tube in thermal contact with the semiconductor module; The header has an insertion hole into which an end of the flat tube is inserted, a seal member for watertightly sealing a gap between an outer peripheral surface of the flat tube and an inner peripheral surface of the insertion hole, and a coolant flow path communicating with the insertion hole, The sealing member is attached to the insertion hole and has a sealing portion that watertightly seals the gap, an abutting portion that abuts against the header in the flat tube insertion direction on the opening side of the insertion hole, and a clamped portion that is clamped between the tip of the flat tube inserted into the insertion hole and the bottom of the insertion hole, The sealing member has a first tapered surface formed in a region facing the bottom of the insertion hole, The power conversion device, wherein the insertion hole has a second tapered surface formed opposite to the first tapered surface.

2. The power conversion device according to claim 1, The sealing member is a ring-shaped columnar body that surrounds the outer periphery of the flat tube; a first sealing portion formed around the entire circumference so as to protrude from an outer peripheral surface of the columnar body; a second sealing portion formed around the entire circumference so as to protrude from the inner circumferential surface of the columnar body; the abutment portion formed so as to protrude from the outer peripheral surface of the columnar body.

3. 3. The power conversion device according to claim 1, a first flat tube and a second flat tube provided to sandwich the semiconductor module; Each of the pair of headers includes a first header attached to an end of the first flat tube and a second header attached to an end of the second flat tube and stacked on the first header, The first header has a through hole formed therein that communicates with the cooling flow path of the first header, an O-ring seal attached to the outer periphery thereof, and a shaft portion that protrudes in the stacking direction; The second header has a hole that communicates with the cooling flow path of the second header and into which the shaft portion is inserted in the stacking direction.

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