Power conversion device

Abstract

A technology is provided for preventing a sealing component that seals a semiconductor element from leaking from between a resin case and a heat sink. A power conversion device (10) includes: a heat sink (40) having a mounting surface (41) on which semiconductor elements (31 to 33) are mounted; a resin case (50) having a close contact surface (51) that is in close contact with the mounting surface (41) and accommodates the semiconductor elements (31 to 33); and a sealing component (12) that seals the semiconductor elements (31 to 33) in the case (50). A first enclosure (60) that surrounds the semiconductor elements (31 to 33) is provided on the mounting surface (41) of the heat sink (40). A second enclosure (70) that surrounds the semiconductor elements (31 to 33) is provided on the close contact surface (51) of the case (50). The first enclosure (60) and the second enclosure (70) are fitted into each other in a concave-convex shape.

Description

Technical Field

[0001] The present invention relates to a power conversion device in which a resin case is fixed to a heat sink of a semiconductor element. Background Art

[0002] The power conversion device is disposed between a battery and a motor, for example, and controls the power stored in the battery and supplies it to the motor. As a semiconductor device constituting a part of the power conversion device, there is a conventional technology disclosed in Patent Document 1.

[0003] The semiconductor device disclosed in Patent Document 1 includes a semiconductor element; a heat sink that dissipates heat generated by the semiconductor element; a resin case that houses the semiconductor element; and a sealing member that seals the semiconductor element.

[0004] The heat sink includes a top plate having a mounting surface on which the semiconductor element is mounted, and fins provided on a surface opposite to the mounting surface.

[0005] The resin case includes a bottom plate portion having an opposing surface facing the mounting surface, and a side wall portion extending upward from a peripheral edge of the bottom plate portion.

[0006] The process of fixing the housing to the heat sink is described. A plurality of protrusions are provided on the mounting surface of the substrate of the heat sink. The plurality of protrusions are arranged in a ring shape at predetermined intervals. An adhesive is applied along the plurality of protrusions on the mounting surface. The top plate portion of the heat sink and the bottom plate portion of the resin housing are fixed to each other by screws. The interval between the bottom plate portion and the top plate portion is kept fixed according to the protrusion amount of the protrusion.

[0007] The process of sealing the semiconductor element is described below. A gel-like sealing member is poured into a region surrounded by the side wall portion of the housing, and the sealing member is solidified to seal the semiconductor element.

[0008] Prior art literature

[0009] Patent Literature

[0010] Patent Document 1: Japanese Patent Application Publication No. 2005-322784 Summary of the invention

[0011] Problems to be solved by the invention

[0012] The material of the housing and the material of the heat sink have different coefficients of thermal expansion. The housing is made of resin. When the housing is taken out of the mold and cooled, the resin shrinks and the housing may warp. For example, when warping occurs in the bottom plate portion of the housing, the gap between the opposing surface of the bottom plate portion of the housing and the mounting surface of the top plate portion of the heat sink increases. In the process of sealing the semiconductor element housed in the housing, when a gel-like sealing component flows into the housing, the sealing component may leak to the outside from the gap between the mounting surface of the heat sink and the opposing surface of the housing. It is desirable to have a structure that prevents leakage of the sealing component.

[0013] An object of the present invention is to provide a technique capable of preventing a sealing member sealing a semiconductor element from leaking from between a resin case and a heat sink.

[0014] Means for solving problems

[0015] According to the first aspect of the invention, there is provided a power conversion device, comprising: a semiconductor element; a heat sink having a mounting surface on which the semiconductor element is mounted; a resin housing having a contact surface that is in close contact with the mounting surface and that accommodates the semiconductor element; and a sealing member that seals the semiconductor element within the housing.

[0016] The housing and the heat sink are respectively provided with fixing parts for fixing each other.

[0017] It is characterized in that

[0018] A first surrounding portion is provided on the mounting surface of the heat sink, and when viewed from a direction along a normal line of the mounting surface, the first surrounding portion surrounds the semiconductor element.

[0019] A second surrounding portion is provided on the close contact surface of the housing, and when viewed from a direction along a normal line of the close contact surface, the second surrounding portion surrounds the semiconductor element.

[0020] The first surrounding portion and the second surrounding portion are fitted into each other in a concave-convex shape.

[0021] As described in claim 2, preferably, one of the first surrounding portion and the second surrounding portion is formed of a continuous groove portion.

[0022] The other of the first surrounding portion and the second surrounding portion is formed of a continuous protrusion that can be fitted into the groove portion.

[0023] As described in claim 3, preferably, when viewed from a direction along the normal line of the surface on which the groove is provided,

[0024] The groove is rectangular in shape and is composed of a pair of long sides parallel to each other and a pair of short sides parallel to each other.

[0025] The cross-sectional shape of the short side portion is a taper whose width increases from the bottom of the short side portion toward the opening.

[0026] The protrusion has a shape along the groove.

[0027] As described in claim 4, preferably, each of the fixing portions is located only in the center in the longitudinal direction of the housing.

[0028] As described in claim 5, preferably, a through hole is provided in the fixing portion of the heat sink.

[0029] A through portion penetrating the through hole is provided integrally with the housing at the fixing portion of the housing, and a size of a distal end of the through portion is larger than an inner diameter of the through hole.

[0030] Effects of the Invention

[0031] In the first aspect, the power conversion device comprises: a heat sink having a mounting surface on which a semiconductor element is mounted; and a resin housing having a close contact surface that is in close contact with the mounting surface and accommodating the semiconductor element. A first enclosing portion is provided on the mounting surface of the heat sink, and the first enclosing portion surrounds the semiconductor element when viewed from a direction along the normal direction of the mounting surface. A second enclosing portion is provided on the close contact surface of the housing, and the second enclosing portion surrounds the semiconductor element when viewed from a direction along the normal direction of the close contact surface. The first enclosing portion and the second enclosing portion are fitted into each other in a concave-convex shape.

[0032] That is, mutually fitting concave-convex parts are respectively provided on the mounting surface of the housing and the close-fitting surface of the resin housing. When viewed from the direction along the normal direction of the surface, these concave-convex parts surround the semiconductor element. Therefore, when a sealing component used to seal the semiconductor element flows into the resin housing, even if the sealing component is immersed between the mounting surface and the close-fitting surface, the sealing component will be blocked by the surrounding parts that are fitted in a concave-convex shape. Leakage of the sealing component can be prevented without using an adhesive.

[0033] Furthermore, the first surrounding portion and the second surrounding portion fit together in a concave-convex shape, so the housing and the heat sink can be fixed to each other at a predetermined position.

[0034] In the second aspect, one of the first surrounding portion and the second surrounding portion is formed by a continuous annular groove portion, and the other of the first surrounding portion and the second surrounding portion is formed by a continuous protrusion portion that can be fitted into the groove portion. Compared with the case where the concavo-convex portions are intermittently formed on the mounting surface and the close contact surface, the sealing member can be more reliably blocked.

[0035] In the third aspect, the groove portion is rectangular in shape and is composed of a pair of long sides parallel to each other and a pair of short sides parallel to each other. The cross-sectional shape of the short side portion is a cone whose width increases from the bottom of the short side portion toward the opening. The protrusion is shaped along the groove portion. In the case where the shell is warped, the displacement in the long side direction is greater than that in the short side direction. That is, the portion extending in the short side direction is greatly displaced in the long side direction. The closer the groove portion of the short side portion is to the boundary between the shell and the heat sink, the greater its width. The groove portion at the short side portion is easily disengaged from the protrusion. The heat sink can be prevented from warping as the shell warps.

[0036] In the fourth aspect, the fixing portion is located only in the center of the long side direction of the housing. If only one end in the long side direction is fixed, the other end of the housing floats relative to the radiator, and the distance between the other end of the housing and the radiator increases. On the other hand, if the fixing portion is located in the center, both ends float, but the distance between each end and the radiator can be reduced.

[0037] In the fifth aspect, a through hole is provided in the fixing portion of the heat sink. A through portion penetrating the through hole is provided in the fixing portion of the shell and the shell as a whole, and the end of the shaft portion of the fixing portion is larger than the inner diameter of the through hole. Therefore, the through portion will not fall off from the through hole. When forming the shell, the shell and the heat sink can be formed as one body. Fastening components such as screws are not required, and the number of components can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a cross-sectional view of a power module constituting the power conversion device of the embodiment.

[0039] Figure 2 yes Figure 1 An exploded perspective view of the power module is shown.

[0040] Figure 3 Yes Figure 2 FIG. 2 is a diagram for explaining the mounting surface of the heat sink and the contact surface of the housing.

[0041] Figure 4 It is a bird's-eye view Figure 1 A view of the upper surface of the housing is shown.

[0042] Figure 5 (a) is a cross-sectional view along line 5a-5a. Figure 5 (b) is a cross-sectional view along line 5b-5b. Figure 5 (c) is a cross-sectional view along line 5c-5c.

[0043] Figure 6 (a) is a diagram for explaining a housing integrally formed with a heat sink according to a comparative example. Figure 6(b) is a diagram for explaining a housing integrally formed with a heat sink according to an embodiment. DETAILED DESCRIPTION

[0044] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0045] exist Figure 1 2 shows a power module 11 constituting the power conversion device 10. The power conversion device 10 is mounted on a vehicle, for example, and is disposed between a battery and a motor, and controls the power stored in the battery and supplies the power to the motor.

[0046] Reference Figure 1 and Figure 2 The power module 11 includes a generator 31 (hereinafter referred to as the first semiconductor 31) for extracting electric power from the engine, a voltage control unit 32 (hereinafter referred to as the second semiconductor 32), a traction controller 33 (hereinafter referred to as the third semiconductor 33), a heat sink 40 on which the first semiconductor 31 to the third semiconductor 33 are mounted and which dissipates heat generated from the semiconductors 31 to 33, a resin case 50 that accommodates the first semiconductor 31 to the third semiconductor 33, a sealing member 12 that seals the first semiconductor 31 to the third semiconductor 33, and a circuit board 13 that controls the motor. The circuit board 13 and the first semiconductor 31 to the third semiconductor 33 are electrically connected via a terminal 14 provided on the case 30.

[0047] The power module 11 is mounted on the upper part of the housing 20 of the power conversion device 10. A flow path 21 for flowing a coolant for cooling the radiator 40 is provided on the upper surface 20a of the housing 20. The flow path 21 is open upward and is blocked by the radiator 40.

[0048] Reference Figure 2 The opening of the flow path 21 is rectangular. A sealing member 15 is provided along the edge 22 of the opening of the flow path 21. The portion of the sealing member 15 extending in the long side direction is set as a pair of long sides 15a, 15a. Concave portions 23 open toward the heat sink 40 are respectively formed on the outer sides of the pair of long sides 15a, 15a. Screw holes 24 are provided at the four corners of the edge 22 of the opening.

[0049] The inner surface of the flow path 21 is composed of a bottom surface 25 having a refrigerant inlet 25a and a refrigerant outlet 25b, a pair of long wall surfaces 26, 26 extending in the longitudinal direction and facing each other, and a pair of short wall surfaces 27, 27 extending in the transverse direction and facing each other. The refrigerant flows along the long wall surfaces 26, 26.

[0050] As a material of the heat sink 40, for example, copper plated with nickel can be used. The heat sink 40 includes: a top plate portion 42 having a mounting surface 41 on which the first to third semiconductors 31 to 33 can be mounted; and fins 44 provided on a lower surface 43 opposite to the mounting surface 41 and capable of contacting the refrigerant flowing in the flow path 21. The lower surface 43 of the top plate portion 42 abuts against the edge 22 of the opening of the flow path 21.

[0051] The housing 50 comprises: a bottom plate portion 52 having a close contact surface 51 that can be in close contact with the mounting surface 41 of the heat sink 40; a peripheral wall portion 54 disposed on an upper surface 53 opposite to the close contact surface 51; and two partition portions 55, 55 that separate the area surrounded by the peripheral wall portion 54.

[0052] The bottom plate portion 52 has a first exposure hole 52 a for exposing the first semiconductor 31 . Similarly, the bottom plate portion 52 has a second exposure hole 52 b for exposing the second semiconductor 32 and a third exposure hole 52 c for exposing the third semiconductor 33 .

[0053] Fixing holes 45 are formed at four corners of the top plate portion 42 of the heat sink 40. Fixing holes 56 are formed at four corners of the bottom plate portion 52 of the housing 50. Fastening members such as screws 16 pass through the fixing holes 56 and 45 and are fastened to the threaded holes 24. Thus, the heat sink 40 and the housing 50 are fixed to the upper surface 20a of the frame 20.

[0054] The circuit board 13 has fixing holes 13a at four corners. The peripheral wall 54 has threaded holes 54a at four corners. Fastening members such as screws 17 pass through the fixing holes 13a and are fastened to the threaded holes 54a. Thus, the circuit board 13 is fixed to the upper end surface 54b of the peripheral wall 54 of the housing 50.

[0055] Reference Figure 3 The mounting surface 41 of the heat sink 40 and the close contact surface 51 of the housing 50 that can be in close contact with the mounting surface 41 are fitted with each other through a concave-convex fitting structure 18. The fitting structure 18 is composed of a continuous annular groove portion 60 (first surrounding portion) formed on the mounting surface 41 of the top plate portion 42 of the heat sink 40, and an annular protrusion 70 (second surrounding portion) formed on the close contact surface 51 of the heat sink 40 and capable of fitting with the groove portion 60.

[0056] When viewed from the direction along the normal line of the mounting surface 41 , the groove portion 60 has a rectangular shape and has a pair of long groove portions 61 (long sides) parallel to each other and a pair of short groove portions 62 (short sides) parallel to each other.

[0057] The protrusion 70 surrounds the first to third exposure holes 52a to 52c and has a rectangular shape when viewed from the direction along the normal direction of the contact surface 51, and has a pair of parallel long protrusions 71 (long sides) and a pair of parallel short protrusions 72 (short sides).

[0058] In addition, the fitting structure 18 may be a structure in which the protrusion 70 is formed on the radiator 40 and the groove 60 is formed on the housing 50. Furthermore, the fitting structure 18 may be a structure in which a plurality of concave and convex parts are intermittently arranged in a ring shape.

[0059] Reference Figure 4 The two partitions 55, 55 divide the area inside the peripheral wall portion 54 into a first area 57 to a third area 59. The first semiconductor 31 exposed from the first exposure hole 52a is located in the first area 57. The second semiconductor 32 exposed from the second exposure hole 52b is located in the second area 58. The third semiconductor 33 exposed from the third exposure hole 52c is located in the third area 59. When viewed from the direction along the normal line of the upper surface 53 of the bottom plate portion 52 (refer to Figure 4 ), the protrusion 70 surrounds the peripheral wall portion 54.

[0060] exist Figure 5 (a) shows a cross section of the interlocking structure 18 composed of the long groove portion 61 and the long protrusion 71. The cross section of the long groove portion 61 is rectangular, and has a first bottom surface 63 parallel to the mounting surface 41 and a pair of first side surfaces 64, 64 extending from both ends of the first bottom surface 63 toward the mounting surface 41. Each first side surface 64 is orthogonal to the mounting surface 41 of the top plate portion 42 of the heat sink 40.

[0061] Each of the long protrusions 71 has a first contact surface 73 that contacts the first bottom surface 63 and second contact surfaces 74 , 74 that contact the first side surfaces 64 , 64 .

[0062] exist Figure 5 (b) shows a cross section of the fitting structure 18 formed of the short groove portion 62 and the short protrusion 72. The cross-sectional shape of the short groove portion 62 is a taper whose width increases from the second bottom surface 65 (bottom) of the short groove portion 62 toward the opening.

[0063] Specifically, the short groove portion 62 has an inwardly inclined surface 66, which is located at the inner side of the second bottom surface 65 (close to the center C of the heat sink 40 and the housing 50 (refer to Figure 4 and an outwardly inclined surface 67, which is inclined outwardly with the other end 65b of the outer side of the bottom surface 25 (in the direction away from the center C) as a base point. The second bottom surface 65 is parallel to the mounting surface 41.

[0064] The short protrusion 72 is shaped along the short groove 62 and has a distal end surface 75 that contacts the second bottom surface 65 , an inner contact surface 76 that contacts the inner inclined surface 66 , and an outer contact surface 77 that contacts the outer inclined surface 67 .

[0065] The short grooves 62 and the short protrusions 72 have the same structure. The description is omitted. The cross-sectional shape of the short grooves 62 and the short protrusions 72 is not limited to the trapezoidal shape shown in the embodiment, but may also be a polygonal shape such as a triangle.

[0066] Reference Figure 2 , Figure 3 The heat sink 40 and the housing 50 have fixing portions 80 and 56 for fixing each other, respectively. The fixing portion 46 of the heat sink 40 is provided integrally with the heat sink 40 on the side surface 47 in the longitudinal direction of the top plate portion 42. The fixing portion 46 of the heat sink 40 is provided with a through hole 46a penetrating in the thickness direction of the top plate portion 42.

[0067] In order to facilitate the description of the interlocking structure 18, Figure 2 and Figure 3 , the housing 50 and the radiator 40 are shown as being separate from each other, but the housing 50 is integrally formed with the radiator 40. That is, the radiator 40 is placed on a mold of the housing 50, and resin is poured into the mold, thereby obtaining the housing 50 integral with the radiator 40.

[0068] Reference Figure 3 , Figure 5 (c). The fixing portion 80 of the shell 50 is integrally provided with the shell 50 on the side surface 52d in the long side direction of the bottom plate portion 52. The fixing portion 80 of the shell 50 has: a base 81, which is provided on the side surface 52d of the bottom plate portion 52; and a through portion 82, which extends from the base 81 to the heat sink 40 and passes through the through hole 46a. The dimension L of the end 83 of the through portion 82 is larger than the inner diameter D of the through hole 46a. In addition, the shell 50 and the heat sink 40 can also be formed independently and fixed to each other by fastening components such as screws.

[0069] The effects of the embodiment will be described.

[0070] Reference Figure 3 , Figure 4 The power conversion device 10 includes: a heat sink 40 having a mounting surface 41 on which a semiconductor element is mounted; and a resin housing 50 having a close contact surface 51 that is in close contact with the mounting surface 41 and accommodates the semiconductor element. A groove 60 (first surrounding portion) that surrounds the semiconductor element is provided on the mounting surface 41 of the heat sink 40. A protrusion 70 (second surrounding portion) that surrounds the semiconductor element is provided on the close contact surface 51 of the housing 50. The groove 60 and the protrusion 70 are fitted into each other in a concave-convex shape (see FIG. 1 ). Figure 5(a) Figure 5 (b)).

[0071] Reference Figure 1 , Figure 4 When sealing the first semiconductor 31, the gel-like sealing member 12 is flowed into the first region 57. Even if the sealing member 12 is inserted between the mounting surface 41 and the close contact surface 51, the sealing member 12 is blocked by the groove 60 and the protrusion 70 that fit in a concave-convex shape. Therefore, the sealing member 12 can be prevented from leaking without using an adhesive.

[0072] Furthermore, since the groove portion 60 and the protrusion 70 are fitted in a concave-convex shape, the housing 50 and the radiator 40 can be fixed to each other at predetermined positions.

[0073] Reference Figure 3 The groove portion 60 is continuously formed. The protrusion 70 is continuously formed. For example, compared with a fitting structure in which projections and depressions are intermittently formed on both the mounting surface 41 and the contact surface 51 , the sealing member that penetrates between the housing 50 and the radiator 40 can be more reliably blocked.

[0074] Reference Figure 4 When the housing 30 is warped, the displacement in the long-side direction is larger than that in the short-side direction. That is, the pair of short protrusions 72 and 72 are displaced in the long-side direction so as to approach each other.

[0075] Reference Figure 6 (a). In the comparative example, the short grooves 102, 102 of the heat sink 101 have a rectangular cross section. The short protrusions 104, 104 of the housing 103 have a rectangular cross section. The side surfaces 105, 105 of the short grooves 102 are orthogonal to the mounting surface 108. The side surfaces 106, 106 of the short protrusions 104 are orthogonal to the close contact surface 107.

[0076] After the housing 103 is molded, the housing 103 contracts after cooling, and the housing 103 is deformed so that the short protrusions 104, 104 approach each other. Due to the warping of the housing 103, the short protrusions 104, 104 are hooked on the short grooves 102, 102. As the housing 103 warps, the heat sink 101 also warps.

[0077] Reference Figure 5 The short groove portion 62 has an inner inclined surface 66 inclined inwardly and an outer inclined surface 67 inclined outwardly. The short protrusion 72 has an inner contact surface 76 abutting against the inner inclined surface 66 and an outer contact surface 77 abutting against the outer inclined surface 67.

[0078] Reference Figure 6(b). Any of the side surfaces 66, 67, 76, 77 are inclined, so the incline surface 66 easily slides relative to the inner connecting surface 76. The end surface 75 and the corner 78 of the outer connecting surface 77 are difficult to contact the outer connecting surface 67. The short groove portion 62 and the short protrusion 72 are easily disengaged. The heat sink 40 can be prevented from warping as the housing 50 warps.

[0079] Reference Figure 4 , Figure 6 (b). The fixing portion 80 of the housing 50 is located in the center of the long side direction of the housing 50. If the fixing portion 80 is provided at one end 50a in the long side direction, the other end 50b of the housing 50 floats relative to the radiator 40, and the distance between the other end 50b of the housing 50 and the radiator 40 is greatly increased. On the other hand, if the fixing portion 80 is located in the center of the housing 50, although both ends float, the distance between each end 50a, 50b and the radiator 40 can be reduced.

[0080] Reference Figure 5 (c). A through hole 46a that penetrates in the thickness direction of the top plate portion 42 is provided in the fixing portion 46 of the heat sink 40. The fixing portion 80 of the shell 50 has a through portion 82 that penetrates the through hole 46a. The dimension L of the end 83 of the through portion 82 is larger than the inner diameter D of the through hole 46a. Therefore, the through portion 82 will not fall off from the through hole 46a. When forming the shell 50, the shell 50 and the heat sink 40 can be formed as a whole. Fastening components such as screws are not required, and the number of components can be reduced.

[0081] Reference Figure 2 , Figure 5 (c) The end 83 of the through portion 82 is inserted into the recess 23 formed on the upper surface 20 a of the frame 20 . The recess 23 has a function of positioning the power module 11 when it is mounted on the frame 20 .

[0082] Furthermore, the power conversion device of the present invention can be mounted on other vehicles besides hybrid vehicles. That is, the present invention is not limited to the embodiments as long as the functions and effects of the present invention are achieved.

[0083] Industrial Application Possibility

[0084] The power conversion device of the present invention is suitable for a four-wheeled vehicle.

[0085] Description of symbols

[0086] 10: Power conversion device;

[0087] 11: Power module;

[0088] 12: Closing parts;

[0089] 18: Mosaic structure;

[0090] 31: generator (first semiconductor);

[0091] 32: voltage control unit (second semiconductor);

[0092] 33: traction controller (third semiconductor);

[0093] 40: heat sink;

[0094] 41: mounting surface;

[0095] 42: top plate;

[0096] 46: fixing portion, 46a: through hole;

[0097] 47: side;

[0098] 50: housing;

[0099] 51: close to the surface;

[0100] 52: bottom plate;

[0101] 60: groove portion (first surrounding portion);

[0102] 61: long groove portion (long side portion);

[0103] 62: short groove portion (short side portion);

[0104] 63: first bottom surface;

[0105] 64: first side;

[0106] 65: second bottom surface, 65a: one end, 65b: the other end;

[0107] 66: inward surface;

[0108] 67: camber surface;

[0109] 70: protruding portion (second surrounding portion);

[0110] 71: long protrusion (long side);

[0111] 72: short protrusion (short side);

[0112] 73: first abutting surface;

[0113] 74: second abutting surface;

[0114] 75: End face;

[0115] 76: Internal surface;

[0116] 77: circumferential surface;

[0117] 78: horn;

[0118] 80: fixed part;

[0119] 81: base;

[0120] 82: through part;

[0121] 83: end;

[0122] C: center of the shell;

[0123] L: size of the end;

[0124] D: Inner diameter of the through hole.

Claims

1. A power conversion device, comprising: Semiconductor components; a heat sink having a mounting surface on which the semiconductor element is mounted; a resin housing having a contact surface that contacts the mounting surface and that accommodates the semiconductor element; and a sealing member for sealing the semiconductor element in the housing, The housing and the heat sink are respectively provided with fixing parts for fixing each other. It is characterized in that A first surrounding portion is provided on the mounting surface of the heat sink, and when viewed from a direction along a normal line of the mounting surface, the first surrounding portion surrounds the semiconductor element. A second surrounding portion is provided on the close contact surface of the housing, and when viewed from a direction along a normal line of the close contact surface, the second surrounding portion surrounds the semiconductor element. The first surrounding portion and the second surrounding portion are fitted into each other in a concave-convex shape. Either the first surrounding portion or the second surrounding portion is formed by a continuous groove portion, The other of the first surrounding portion and the second surrounding portion is composed of a continuous protrusion that can be fitted into the groove portion. When viewed from the direction along the normal line of the surface provided with the groove, The groove is rectangular in shape and is composed of a pair of long sides parallel to each other and a pair of short sides parallel to each other. The cross-sectional shape of the short side portion is a taper whose width increases from the bottom of the short side portion toward the opening. The protrusion has a shape along the groove.

2. The power conversion device according to claim 1, characterized in that: Each of the fixing portions is located only at the center of the housing in the long side direction.

3. The power conversion device according to claim 1 or 2, characterized in that: A through hole is provided in the fixing portion of the heat sink, A through portion penetrating the through hole is provided integrally with the housing at the fixing portion of the housing, and a size of a distal end of the through portion is larger than an inner diameter of the through hole.

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