Power Conversion Device

Abstract

To provide a power conversion device that can be miniaturized. [Solution] A power conversion device (10) includes a heat sink (20), a substrate (30) disposed on the heat sink (20), input / output terminals (40) erected on the substrate (30), a fastening member (50), and an elastic member (60). The fastening member (50) is composed of a bolt (51) and a nut (54), and a shaft portion (52) of the bolt (51) passes through the heat sink (20), the substrate (30), and the input / output terminals (40) in the direction of extension of an axis (L). The elastic member (60) is press-fitted into at least one of a space between the shaft portion (52) and the heat sink (20) and a space between the shaft portion (52) and the input / output terminals (40). The fastening member (50) fastens the heat sink (20), the input / output terminals (40), and the substrate (30) in the direction of extension of the axis (L) by a flange portion (53) and a nut (54) of the bolt (51), and is held in place by the elastic member (60) in at least one of a space between the shaft portion (52) and the heat sink (20) and a space between the shaft portion (52) and the input / output terminals (40).

Description

[Technical Field]

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

[0002] For example, the power conversion device disclosed in Patent Document 1 includes a heat sink, a substrate, and terminals serving as input / output terminals. In the power conversion device, the terminals are formed by connecting a first conductive member and a second conductive member. The first conductive member is fixed to the heat sink by a first screw threaded into the heat sink. The second conductive member is connected to a terminal of an external wiring electrically connected to the substrate via the terminal by a second screw threaded into the second conductive member. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-204917 Summary of the Invention [Problem to be solved by the invention]

[0004] However, there is a risk that the size of the power converter will increase by the length of the first screw and the second screw in the direction in which the axes of the input / output terminals extend. [Means for solving the problem]

[0005] A power conversion device for solving the above-mentioned problems includes a heat sink, a substrate disposed on the heat sink and having switching elements mounted thereon, and input / output terminals erected on the substrate for electrically connecting the substrate to external terminals, the input / output terminals being connected to the external terminals at one end in the direction of extension of an axis and connected to the substrate at the other end, and the power conversion device is configured with a bolt having a shaft portion provided with a flange portion at its base end and a nut screwed onto the tip end of the shaft portion, and the input / output terminals are inserted into through holes formed by the heat sink, the substrate, and the input / output terminals. and an elastic member pressed into at least one of the spaces between the shaft portion and the heat sink and the spaces between the shaft portion and the input / output terminals while spacing the shaft portion from the heat sink and the input / output terminals, wherein the fastening member fastens the heat sink, the input / output terminals, the substrate, and the external terminals in the direction of extension of the axis by the flange portion and the nut, and is held in place by the elastic member at least one of the spaces between the shaft portion and the heat sink and the spaces between the shaft portion and the input / output terminals.

[0006] According to this, the input / output terminals are attached to the heat sink and the circuit board and connected to the external terminals by fastening members consisting of one bolt and one nut. For example, compared to a case in which the input / output terminals are fastened to the heat sink, the circuit board, and the external terminals by separate members, the power conversion device configured as described above can reduce the number of parts.

[0007] Furthermore, the power conversion device can reduce the area occupied by fastening members compared to a case in which separate members are provided for attaching the input / output terminals to the heat sink and for attaching external terminals to the input / output terminals. In other words, the power conversion device can reduce the space required in the axial direction for attaching the input / output terminals. Therefore, with the above configuration, the power conversion device can be downsized by reducing the number of parts and the area occupied in the axial direction by the members for attaching the input / output terminals. As described above, the power conversion device can be downsized.

[0008] Furthermore, the bolt is held between the shaft and the heat sink and / or between the shaft and the input / output terminals by an elastic member press-fitted between the shaft and the heat sink and / or between the shaft and the input / output terminals. Therefore, even when the nut is loosened to attach or detach the external terminals, the elastic member prevents the bolt from moving between the shaft and the heat sink and / or between the shaft and the input / output terminals. In other words, the power converter includes an elastic member, which improves the ease of attaching the external terminals to the input / output terminals. Furthermore, because the elastic member is disposed inside the through-hole, the power converter achieves this improved ease of attachment without increasing the dimensions of the power converter. In other words, the power converter includes an elastic member inside the through-hole, which improves the ease of attachment while miniaturizing the power converter.

[0009] In the power conversion device, the fastening member may have the shaft portion inserted into the through hole from the end on the heat sink side, the tip portion protruding from the input terminal, and the nut abutting against the external terminal.

[0010] According to this, the fastening member has a flange portion protruding from the end of the through hole facing the heat sink and a nut protruding from the end facing the input / output terminal. Therefore, the external terminal is attached to the input / output terminal by removing the nut from the tip of the shank and then attaching the external terminal to the tip. If the shank is inserted into the through hole from the external terminal side, it is necessary to remove the shank from the through hole to attach the external terminal to the input / output terminal. However, with the above configuration, the external terminal can be attached with the shank inserted in the through hole. Therefore, the power conversion device with the above configuration can improve the workability of attaching the external terminal to the input / output terminal.

[0011] In the power conversion device, the heat sink has a recess on its outer surface, which is the opposite side to the surface facing the substrate, that is recessed from the outer surface of the heat sink and opens in the direction in which the axis extends, and the flange portion is accommodated in the recess.

[0012] According to this, by accommodating the flange portion in the recess, the power converter can prevent the flange portion from protruding from the heat sink. As a result, the power converter can be made smaller in size in the direction of extension of the axis compared to when the flange portion protrudes from the heat sink. Furthermore, by accommodating the flange portion in the recess, when the heat sink is placed on a base, for example, the power converter can suppress interference of the bolt with the base. As a result, the power converter can be more easily attached to a base external to the power converter compared to when the power converter does not have a recess.

[0013] In the power conversion device, the flange portion may be polygonal when viewed in a thickness direction of the flange portion, and the recess may be polygonal in a plan view of the outer surface of the heat sink so as to engage with the flange portion.

[0014] According to this, the flange portion is engaged with the recessed portion, thereby restricting rotation within the recessed portion. By engaging with the flange portion, the recessed portion prevents the bolt from rotating together with the nut, for example, when fastening the nut to the bolt. In other words, the power conversion device can easily attach the nut to the bolt because the recessed portion has a polygonal shape that engages with the flange portion.

[0015] The power conversion device may further include a resin member interposed between the heat sink and the bolt and insulating the heat sink from the bolt. According to this, the resin member is separate from the heat sink and the bolt. Therefore, even if the insulation between the heat sink and the bolt deteriorates due to aging or the usage environment, the insulation can be maintained by replacing the resin member. In other words, the power conversion device can be more easily maintained than a power conversion device without the resin member.

[0016] In the power conversion device, the elastic member may comprise a first elastic member arranged in the through hole between the shaft portion and the input / output terminal, and a second elastic member arranged between the bolt and the heat sink.

[0017] According to this, by dividing the elastic member into the first elastic member and the second elastic member, the length of each elastic member in the direction of extension of the axis is shorter than when the elastic member is arranged over the entire through hole. This makes it easier to press-fit the elastic member into the through hole compared to, for example, when the elastic member is a single member press-fitted over the entire through hole. Furthermore, the first elastic member and the second elastic member constituting the elastic member are each arranged at two locations near both ends in the direction of extension of the axis of the through hole through which the shaft portion is inserted. Therefore, installation of the elastic member is easier than when the elastic member is press-fitted to the center of the through hole in the direction of extension of the axis. As described above, the power conversion device can easily install the elastic member by dividing the elastic member into the first elastic member and the second elastic member and arranging them respectively near each end of the through hole in the direction of extension of the axis.

[0018] In the power converter, the elastic member may seal at least one of the gap between the shaft portion and the heat sink and the gap between the shaft portion and the input / output terminal. This makes it possible to prevent the space in the power converter in which the substrate is disposed from communicating with the outside of the power converter via the through hole. [Effects of the Invention]

[0019] According to the present invention, the power conversion device can be made smaller. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is an exploded perspective view showing a power conversion device. [Figure 2] FIG. 2 is a cross-sectional view showing the power conversion device. [Figure 3] FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0021] An embodiment of a power conversion device will be described below. In this embodiment, the power conversion device is an inverter device mounted on a vehicle. That is, the power conversion device of this embodiment receives power from a battery mounted on the vehicle, converts the power, and then outputs the power to a load mounted on the vehicle.

[0022] <Overall view of power conversion equipment> As shown in FIGS. 1 and 2, the power conversion device 10 includes a heat sink 20, a resin member 24, a cover 26, a substrate 30, input / output terminals 40, fastening members 50, and an elastic member 60. The power conversion device 10 includes a plurality of input / output terminals 40. The power conversion device 10 of this embodiment includes five input / output terminals 40. As will be described later, the power conversion device 10 includes a resin member 24, a fastening member 50, and an elastic member 60 for each input / output terminal 40. Note that FIG. 1 only shows the resin member 24, fastening member 50, and elastic member 60 for one input / output terminal 40, while omitting the resin member 24, fastening member 50, and elastic member 60 for the other input / output terminals 40. Also, FIG. 2 only shows the resin member 24, fastening member 50, and elastic member 60 for one input / output terminal 40.

[0023] The heat sink 20 has a rectangular plate shape and is made of, for example, aluminum. The heat sink 20 has a heat sink outer surface 21 and a heat sink installation surface 22 in the thickness direction of the heat sink 20.

[0024] As shown in FIG. 2, the heat sink 20 has recesses 23 in the heat sink outer surface 21. The recesses 23 are portions recessed from the heat sink outer surface 21. Although not shown, the heat sink 20 has five recesses 23 corresponding to the positions of the input / output terminals 40. The recesses 23 open toward the outside of the heat sink 20 in the thickness direction of the heat sink 20. The opening direction of the recesses 23 coincides with the thickness direction of the heat sink 20. As shown in FIG. 3, the heat sink 20 has a polygonal shape in a plan view seen from the thickness direction of the heat sink 20. The recesses 23 in this embodiment are hexagonal.

[0025] A resin member 24 is provided in the recess 23 of the heat sink 20. The resin member 24 is an insulating member. In a plan view seen from the thickness direction of the heat sink 20, the resin member 24 has the same shape as the recess 23. That is, the resin member 24 in this embodiment is hexagonal. The entire outer surface of the resin member 24 is in contact with the inner surface of the recess 23. As shown in FIGS. 1 and 2, a through hole is formed in the center of the resin member 24.

[0026] As shown in Fig. 1, the heat sink mounting surface 22 is slightly recessed in the area where the substrate 30 is mounted. Furthermore, as shown in Fig. 2, the heat sink 20 has a protrusion 25 on the heat sink mounting surface 22. The protrusion 25 is a portion that protrudes slightly from the heat sink mounting surface 22 in the thickness direction of the heat sink 20. The protrusion 25 is aligned with the recess 23 in the thickness direction of the heat sink 20.

[0027] The heat sink 20 has a first insertion hole 20a at a portion aligned with the recessed portion 23 and the protruding portion 25 in the thickness direction of the heat sink 20. The first insertion hole 20a penetrates the heat sink 20 in the thickness direction of the heat sink 20. One end of the first insertion hole 20a opens at the recessed portion 23, and the other end opens at the protruding portion 25.

[0028] As shown in Fig. 1, the cover 26 is installed on the heat sink installation surface 22. The cover 26 and the heat sink 20 define an accommodation space 10a shown in Fig. 2. The cover 26 is fixed to a portion of the heat sink 20 near the edge.

[0029] The cover 26 has four side plates 261 and a top plate 262. The side plates 261 are erected on the heat sink mounting surface 22. The four side plates 261 are erected on four edge portions of the heat sink 20, respectively. The side plates 261 are fixed to these edge portions. The top plate 262 is connected to the ends of the four side plates 261 opposite the ends connected to the heat sink 20. The heat sink 20, the four side plates 261, and the top plate 262 define the housing space 10a shown in FIG. 2. The top plate 262 is provided with terminal holes 26a through which the input / output terminals 40 pass. The top plate 262 has five terminal holes 26a corresponding to the five input / output terminals 40. As shown in FIG. 2, the top plate 262 has an O-ring 27 on the inner circumferential surface that defines the terminal holes 26a.

[0030] As shown in Figures 1 and 2, the substrate 30 is placed on the heat sink 20. The substrate 30 is placed on the heat sink mounting surface 22. In other words, the heat sink mounting surface 22 is the surface of the heat sink 20 that faces the substrate 30. The heat sink outer surface 21 is the surface of the heat sink 20 opposite the surface that faces the substrate 30. The substrate 30 is placed on the heat sink 20 with a protrusion 25 slightly spaced from the heat sink mounting surface 22. The substrate 30 is accommodated in the accommodation space 10a.

[0031] Switching elements S are mounted on the substrate 30. The switching elements S are provided on the surface of the substrate 30 facing the heat sink installation surface 22. More specifically, the switching elements S are arranged in a gap formed by a protrusion 25 between the heat sink 20 and the substrate 30. The capacitors C are erected on the surface of the substrate 30 opposite the surface on which the switching elements S are installed.

[0032] 2, the substrate 30 has second insertion holes 30a. Although not shown, the substrate 30 has five second insertion holes 30a corresponding to the five input / output terminals 40. The second insertion holes 30a penetrate the substrate 30 in the thickness direction. The five second insertion holes 30a are aligned with the first insertion holes 20a in the thickness direction of the substrate 30.

[0033] <Input / output terminal> As shown in Fig. 1, the input / output terminal 40 has a cylindrical shape. The input / output terminal 40 is provided on the substrate 30. The input / output terminal 40 is provided upright on the surface of the substrate 30 on which a plurality of capacitors C are provided upright. In other words, the direction in which the axis L of the input / output terminal 40 extends coincides with the thickness direction of the heat sink 20 and the substrate 30. As described above, the recess 23 is provided at a position corresponding to the input / output terminal 40. For this reason, it can be said that the recess 23 is recessed from the outer surface 21 of the heat sink and opens in the direction in which the axis L extends.

[0034] 2, the input / output terminal 40 passes through the terminal hole 26a in the top plate 262. An O-ring 27 seals the gap between the top plate 262 and the input / output terminal 40. As shown in FIGS. 1 and 2 , the power conversion device 10 is electrically connected to an external power supply (not shown) via an external terminal E1 and an external wiring E2. One end of the external wiring E2 is provided with an external terminal E1, and the other end (not shown) is connected to the external power supply. The external terminal E1 is a round terminal. Power is input to the power conversion device 10 from the external power supply via an input / output terminal 40. The power conversion device 10 also outputs power converted internally to the outside via the input / output terminal 40. More specifically, the input / output terminal 40 is connected to the external terminal E1 at one end in the direction of extension of the axis L, and is connected to the substrate 30 at the other end. In this way, the input / output terminal 40 electrically connects the external terminal E1 and the substrate 30. In other words, the input / output terminal 40 is provided upright on the substrate 30 to electrically connect the substrate 30 to the external terminal E1.

[0035] 1, the external terminal E1 and the external wiring E2 for only one of the input / output terminals 40 are shown. The input / output terminals 40 are composed of two input terminals located near the edges of the substrate 30 and an output terminal located closer to the inside of the input terminals on the substrate 30. The input terminals are composed of a positive input electrode and a negative input electrode. The output terminals are composed of a U-phase output electrode, a V-phase output electrode, and a W-phase output electrode.

[0036] Hereinafter, the positive input electrode, negative input electrode, U-phase output electrode, V-phase output electrode, and W-phase output electrode will be collectively referred to as input / output terminals 40. In other words, the configuration of the input / output terminals 40 described below is common to all of the positive input electrode, negative input electrode, U-phase output electrode, V-phase output electrode, and W-phase output electrode.

[0037] The input / output terminal 40 has a third insertion hole 40a. The third insertion hole 40a extends along the axis L and passes through the input / output terminal 40. The third insertion hole 40a is aligned with the second insertion hole 30a in the direction that the axis L extends. In other words, the third insertion hole 40a is aligned with the second insertion hole 30a and the first insertion hole 20a in the direction that the axis L extends. The input / output terminals 40 are erected on the substrate 30 so as to be aligned with the first insertion hole 20a and the second insertion hole 30a in the direction that the axis L extends.

[0038] As shown in FIG. 2, the power conversion device 10 has a bolt insertion hole 10b as a through-hole. The first insertion hole 20a, the second insertion hole 30a, and the third insertion hole 40a form the bolt insertion hole 10b. In other words, the bolt insertion hole 10b is formed by the heat sink 20, the substrate 30, and the input / output terminals 40. The bolt insertion hole 10b extends along the axis L. The bolt insertion hole 10b opens at each of the recess 23 and the input / output terminals 40. Both ends of the bolt insertion hole 10b open to the outside of the accommodation space 10a.

[0039] <Fastening components> As shown in FIGS. 1 and 2, the fastening member 50 includes a bolt 51 and a nut 54. The bolt 51 has a shaft portion 52 and a flange portion 53. The shaft portion 52 has a male thread portion over the entire length in the direction in which the bolt shaft LB extends.

[0040] The flange portion 53 is provided at the base end of the shaft portion 52 so that its thickness direction coincides with the extension direction of the bolt shank LB. The flange portion 53 has a plurality of corners arranged in the circumferential direction. In other words, the flange portion 53 has a polygonal shape when viewed in the thickness direction of the flange portion 53.

[0041] 2, a nut 54 is threaded onto the tip of the shaft 52. In other words, the fastening member 50 is composed of a bolt 51 having a shaft 52 with a flange 53 provided at the base end, and a nut 54 threaded onto the tip of the shaft 52.

[0042] The fastening member 50 has a shaft portion 52 that penetrates the heat sink 20, the substrate 30, and the input / output terminal 40 in the direction of the axis L. In other words, the bolt 51 has a flange portion 53 that is housed in the recess 23 via the resin member 24, and the shaft portion 52 that penetrates the heat sink 20, the substrate 30, the input / output terminal 40, and the external terminal E1. That is, the flange portion 53 is housed in the recess 23. The resin member 24 is also interposed between the heat sink 20 and the bolt 51. As a result, the resin member 24 insulates the heat sink 20 from the bolt 51. A nut 54 is screwed onto the tip of the shaft portion 52 that penetrates the external terminal E1. Due to this screwing, the external terminal E1 is sandwiched between the nut 54 and the input / output terminal 40. In other words, the nut 54 abuts against the external terminal E1.

[0043] The fastening member 50 has a flange portion 53 protruding from the end of the bolt insertion hole 10b on the heat sink 20 side, and a nut 54 protruding from the end on the input / output terminal 40 side. That is, the shank 52 is inserted into the bolt insertion hole 10b from the heat sink 20 side and protrudes from the input / output terminal 40 side. In other words, the bolt 51 is inserted into the bolt insertion hole 10b from the heat sink 20 side. Furthermore, the board 30 and the input / output terminal 40 are inserted into the shank 52 that penetrates the heat sink 20.

[0044] A portion of the heat sink 20, the substrate 30, the input / output terminals 40, and the external terminals E1 are interposed between the flange portion 53 and the nut 54. The fastening member 50 integrates the heat sink 20, the substrate 30, the input / output terminals 40, and the external terminals E1 by screwing the nut 54 onto the tip of the shaft portion 52. In other words, the fastening member 50 fastens the heat sink 20, the input / output terminals 40, the substrate 30, and the external terminals E1 together by the flange portion 53 and the nut 54 in the direction in which the axis L extends.

[0045] 3, the flange portion 53 accommodated in the recess 23 has multiple corners that engage with the recess 23 via the resin member 24. In other words, the recess 23 has a polygonal shape that engages with the flange portion 53 in a plan view of the heat sink outer surface 21. As a result, the recess 23 and the resin member 24 restrict the flange portion 53 from rotating inside the recess 23.

[0046] <Elastic material> The elastic member 60 is provided in the bolt insertion hole 10b defined by the first insertion hole 20a, the second insertion hole 30a, and the third insertion hole 40a. The elastic member 60 is press-fitted into the bolt insertion hole 10b. The shank 52 of the bolt 51 passes through the elastic member 60.

[0047] The elastic member 60 is made up of a first elastic member 61 and a second elastic member 62. In other words, the elastic member 60 is divided into two parts: the first elastic member 61 and the second elastic member 62. The first elastic member 61 is disposed in the bolt insertion hole 10b between the shaft portion 52 and the input / output terminal 40. The first elastic member 61 and the second elastic member 62 are provided in positions spaced apart from each other in the bolt insertion hole 10b.

[0048] The first elastic member 61 is provided in a portion of the third insertion hole 40a that is closer to the external terminal E1 in the direction of extension of the axis L. It can also be said that the first elastic member 61 is provided in a portion of the bolt insertion hole 10b that is closer to the external terminal E1 in the direction of extension of the axis L than the portion where the input / output terminal 40 and the board 30 are connected.

[0049] The first elastic member 61 is press-fitted between the bolt 51 and the input / output terminal 40 while separating the bolt 51 and the input / output terminal 40. Specifically, the first elastic member 61 is press-fitted between the circumferential surface of the shaft portion 52 and the inner circumferential surface of the input / output terminal 40 while separating the circumferential surface of the shaft portion 52 and the inner circumferential surface of the input / output terminal 40 in the radial direction of the bolt 51. The first elastic member 61 holds the bolt 51 relative to the input / output terminal 40. In other words, the first elastic member 61 holds the bolt 51 between the shaft portion 52 and the input / output terminal 40.

[0050] The second elastic member 62 is disposed between the bolt 51 and the heat sink 20. More specifically, the second elastic member 62 is provided in a portion of the first insertion hole 20a that is closer to the heat sink mounting surface 22 than the resin member 24 in the direction in which the axis L extends. It can also be said that the second elastic member 62 is provided in a portion of the heat sink 20 that is closer to the protrusion 25 than the recess 23 in the thickness direction of the heat sink 20. It can also be said that the second elastic member 62 is provided in a portion of the bolt insertion hole 10b that is closer to the heat sink outer surface 21 than the portion where the heat sink 20 and the substrate 30 are connected in the direction in which the axis L extends.

[0051] The second elastic member 62 is press-fitted between the bolt 51 and the heat sink 20 while separating the bolt 51 and the heat sink 20. Specifically, the second elastic member 62 is press-fitted between the circumferential surface of the shaft portion 52 and the inner circumferential surface of the heat sink 20 while separating the circumferential surface of the shaft portion 52 and the inner circumferential surface of the heat sink 20 in the radial direction of the bolt 51. The second elastic member 62 holds the bolt 51 relative to the heat sink 20. In other words, the second elastic member 62 holds the bolt 51 between the shaft portion 52 and the heat sink 20. That is, the fastening member 50 is held relative to the heat sink 20 by the elastic member 60.

[0052] As described above, the elastic member 60 is press-fitted into at least one of the spaces between the shank 52 and the heat sink 20 and the spaces between the shank 52 and the input / output terminals 40, while separating the shank 52 from the heat sink 20 and the input / output terminals 40. In this embodiment, the elastic member 60 is press-fitted into both the spaces between the shank 52 and the heat sink 20 and the spaces between the shank 52 and the input / output terminals 40. Furthermore, the fastening member 50 is held by the elastic member 60 at least one of the spaces between the shank 52 and the heat sink 20 and the spaces between the shank 52 and the input / output terminals 40. In this embodiment, the fastening member 50 is held by the elastic member 60 both between the shank 52 and the heat sink 20 and the spaces between the shank 52 and the input / output terminals 40.

[0053] The term "at least one" used herein means "one or more" of the desired options. For example, if there are two options, the term "at least one" used herein means "only one option" or "both of the two options."

[0054] The first elastic member 61 seals between the shaft portion 52 and the input / output terminal 40. The second elastic member 62 seals between the shaft portion 52 and the heat sink 20. That is, the elastic member 60 seals at least one of the gap between the shaft portion 52 and the heat sink 20 and the gap between the shaft portion 52 and the input / output terminal 40. In the present embodiment, the elastic member 60 seals both the gap between the shaft portion 52 and the heat sink 20 and the gap between the shaft portion 52 and the input / output terminal 40. As a result, the elastic member 60 blocks the exchange of fluid between the outside of the power conversion device 10 and the portion of the bolt insertion hole 10b between the first elastic member 61 and the second elastic member 62.

[0055] <Function of the power conversion device> The power conversion device 10 supplies power input from an external terminal E1 to the substrate 30 via the input / output terminals 40. The power input to the power conversion device 10 is supplied from a battery (not shown) through external wiring E2. The power conversion device 10 converts the input DC power into AC power through the switching operations of multiple switching elements S mounted on the substrate 30, and then outputs the AC power. The power conversion device 10 of this embodiment converts DC power input to the positive and negative electrodes into AC power on the substrate 30, and then outputs the AC power to an on-vehicle load from the U-phase output electrode, V-phase output electrode, and W-phase output electrode. Heat generated on the substrate 30 by this conversion is dissipated to the outside of the power conversion device 10 via the heat sink 20.

[0056] The power conversion device 10 is connected to an external power source via an external terminal E1 and an external wiring E2. The external terminal E1 is attached to the input / output terminal 40. Specifically, the nut 54 is removed from the shaft portion 52 protruding from the input / output terminal 40, and then the external terminal E1 is attached to the tip of the shaft portion 52. The nut 54 is then reattached to the shaft portion 52 to which the external terminal E1 is attached, and the nut 54 is then rotated and screwed onto the shaft portion 52 until the external terminal E1 is sandwiched between the input / output terminal 40 and the nut 54. With the nut 54 screwed onto the shaft portion 52, the external terminal E1 is electrically connected to the input / output terminal 40 while abutting against the end of the input / output terminal 40.

[0057] The external terminal E1 can be removed from the power converter 10 by first removing the nut 54 from the shaft portion 52 and then removing the external terminal E1 from the shaft portion 52. The work of attaching the external terminal E1 to the power conversion device 10 and the work of removing the external terminal E1 from the power conversion device 10 are both performed at the end of the input / output terminal 40 that protrudes from the top plate 262 of the cover 26. In other words, the work is performed outside the accommodation space 10a. In other words, the work is performed without interfering with the components arranged inside the accommodation space 10a.

[0058] [Effects of this embodiment] The effects and functions of this embodiment will be described below. (1) The input / output terminals 40 are attached to the heat sink 20 and the substrate 30 and connected to the external terminals E1 by fastening members 50 each consisting of a bolt 51 and a nut 54. For example, compared to a case in which the input / output terminals 40 are fastened to the heat sink 20, the substrate 30, and the external terminals E1 by separate members, the power conversion device 10 configured as described above can reduce the number of components.

[0059] (2) The power conversion device 10 can reduce the area occupied by the fastening members 50 compared to a case in which the power conversion device 10 has separate members for attaching the input / output terminals 40 to the heat sink 20 and for attaching the external terminals E1 to the input / output terminals 40. In other words, the power conversion device 10 can reduce the space that needs to be secured in the direction along the axis L for attaching the input / output terminals 40. Therefore, with the above configuration, the number of parts can be reduced while the area occupied in the direction along the axis L by the members for attaching the input / output terminals 40 can be reduced, thereby making it possible to miniaturize the power conversion device 10. As described above, the power conversion device 10 can be miniaturized.

[0060] (3) The fastening member 50 is held between the shaft portion 52 and the heat sink 20 and between the shaft portion 52 and the input / output terminals 40 by the elastic member 60 press-fitted between the shaft portion 52 and the heat sink 20 and between the shaft portion 52 and the input / output terminals 40. Therefore, even when the nut 54 is loosened to attach or detach the external terminal E1, the elastic member 60 prevents the fastening member 50 from moving relative to the heat sink 20 and the input / output terminals 40. In other words, the power converter 10 includes the elastic member 60, which improves the ease of attaching the external terminal E1 to the input / output terminals 40. Furthermore, the power converter 10 includes the elastic member 60 disposed inside the bolt insertion hole 10b, which improves the ease of attaching the external terminal E1 to the input / output terminals 40. In addition, the power converter 10 includes the elastic member 60 disposed inside the bolt insertion hole 10b, which improves the ease of attaching the external terminal E1 to the input / output terminals 40. In other words, the power converter 10 includes the elastic member 60 disposed inside the bolt insertion hole 10b, which improves the ease of attaching the external terminal E1 to the input / output terminals 40.

[0061] (4) The fastening member 50 has a flange portion 53 protruding from a base end of the bolt insertion hole 10b that is closer to the heat sink 20, and a nut 54 protruding from a tip end of the fastening member 50 that is closer to the input / output terminal 40. Therefore, the external terminal E1 is attached to the input / output terminal 40 by removing the nut 54 from the end of the bolt 51 and then attaching the external terminal E1 to the end. If the bolt 51 is inserted into the bolt insertion hole 10b from the external terminal E1 side, the shank 52 must be removed from the bolt insertion hole 10b to attach the external terminal E1 to the input / output terminal 40. In the power conversion device 10, the external terminal E1 can be attached with the shank 52 inserted into the bolt insertion hole 10b. This prevents the board 30 from moving in the accommodation space 10a due to the removal of the shank 52. In other words, the external terminal E1 can be attached to the power conversion device 10 without interfering with components arranged inside the accommodation space 10a. As a result, the power conversion device 10 can improve the workability in attaching the external terminal E1 to the input / output terminal 40.

[0062] (5) By accommodating the flange portion 53 in the recess 23, the power conversion device 10 can prevent the flange portion 53 from protruding from the heat sink 20. As a result, the power conversion device 10 can be made smaller in size in the direction of extension of the axis L than when the flange portion 53 protrudes from the heat sink 20. Furthermore, by accommodating the flange portion 53 in the recess 23, when the heat sink 20 is placed on a stand, for example, the power conversion device 10 can suppress interference of the bolt 51 with the stand. As a result, the power conversion device 10 can be more easily attached to a stand external to the power conversion device 10 than when the power conversion device 10 does not have the recess 23.

[0063] (6) The flange portion 53 is engaged with the recessed portion 23, thereby restricting rotation within the recessed portion 23. The recessed portion 23 engages with the flange portion 53, thereby preventing the bolt 51 from rotating together with the nut 54, for example, when the nut 54 is fastened to the shaft portion 52. In other words, the power conversion device 10 can easily attach the nut 54 to the bolt 51 because the recessed portion 23 has a polygonal shape that engages with the flange portion 53.

[0064] (7) The resin member 24 is separate from the heat sink 20 and the bolt 51. Therefore, even if the insulation between the heat sink 20 and the bolt 51 deteriorates due to aging or the usage environment, the insulation can be maintained by replacing the resin member 24. In other words, the power conversion device 10 can be more easily maintained than a power conversion device without the resin member 24.

[0065] (8) The elastic member 60 is inserted between both the heat sink 20 and the input / output terminal 40 and the shaft 52. The elastic member 60 can hold the bolt 51 more securely against the heat sink 20 and the input / output terminal 40 than when the elastic member 60 is press-fitted between either the shaft 52 and the heat sink 20 or the shaft 52 and the input / output terminal 40.

[0066] (9) Because the elastic member 60 is divided into the first elastic member 61 and the second elastic member 62, the length of each elastic member in the direction of extension of the axis L is shorter than when the elastic member 60 is disposed throughout the entire bolt insertion hole 10b. This makes it easier to press-fit the elastic member 60 into the bolt insertion hole 10b compared to, for example, when the elastic member 60 is a single member press-fitted throughout the entire bolt insertion hole 10b. Furthermore, the first elastic member 61 and the second elastic member 62 constituting the elastic member 60 are each disposed in two locations in the bolt insertion hole 10b, near both ends in the direction of extension of the axis L. This makes it easier to install the elastic member 60 compared to when the elastic member 60 is press-fitted all the way into the center of the bolt insertion hole 10b in the direction of extension of the axis L. As described above, the power conversion device 10 can facilitate installation of the elastic member 60 by dividing the elastic member 60 into a first elastic member 61 and a second elastic member 62 and arranging them respectively near each end of the bolt insertion hole 10b in the direction in which the axis L extends.

[0067] (10) The elastic member 60 of the power converter 10 can prevent the accommodation space 10a from communicating with the outside of the power converter 10 through the bolt insertion hole 10b. [Example of change] The above embodiment can be modified as follows: The above embodiment and the following modifications can be combined with each other within the scope of technical compatibility.

[0068] The elastic member 60 does not have to seal both between the shaft portion 52 and the heat sink 20 and between the shaft portion 52 and the input / output terminals 40. Specifically, the elastic member 60 may seal between the heat sink 20 and the shaft portion 52, but not between the input / output terminals 40 and the shaft portion 52. Alternatively, the elastic member 60 may seal between the input / output terminals 40 and the shaft portion 52, but not between the heat sink 20 and the shaft portion 52. In this case, for example, a seal member for sealing a fluid may be provided between the shaft portion 52 and the heat sink 20, as a separate member from the elastic member 60.

[0069] The positions at which the first elastic member 61 and the second elastic member 62 are provided are not limited to those described in the embodiment. The positions of the first elastic member 61 and the second elastic member 62 may be changed as appropriate as long as they are provided at positions that allow the exchange of fluid between the outside of the power conversion device 10 and the accommodation space 10a via the bolt insertion holes 10b to be blocked.

[0070] The elastic member 60 does not have to be divided into the first elastic member 61 and the second elastic member 62. The elastic member 60 may be divided into three or more members. The elastic member 60 may also be a single member. When the elastic member 60 is a single member, it is sufficient that the elastic member 60 is press-fitted into at least one of the spaces between the shaft portion 52 and the heat sink 20 and the space between the shaft portion 52 and the input / output terminal 40.

[0071] The power conversion device 10 does not need to include the resin member 24. In this case, for example, an insulating process is performed between the heat sink 20 and the bolt 51. The key is that the heat sink 20 and the bolt 51 are insulated from each other.

[0072] The flange portion 53 does not have to have a polygonal shape when viewed in the thickness direction of the flange portion 53. For example, the flange portion 53 may have a circular shape when viewed in the thickness direction. In this case, the shape of the recess 23 in the heat sink outer surface 21 in a plan view may be changed as appropriate depending on the shape of the flange portion 53.

[0073] The heat sink 20 does not have to have the recess 23. In other words, the flange 53 may protrude from the heat sink outer surface 21. In this case, the heat sink 20 is preferably configured so that the protruding flange 53 does not interfere with the stand on which the power converter 10 is placed. For example, legs configured to support the power converter 10 may be provided on the portion of the heat sink outer surface 21 where the flange 53 does not protrude.

[0074] The fastening member 50 does not necessarily have to have the nut 54 abut against the external terminal E1. For example, the flange portion 53 may abut against the external terminal E1. That is, the fastening member 50 may have the shaft portion 52 inserted into the bolt insertion hole 10b from the input / output terminal 40 side, and the nut 54 screwed onto the tip portion protruding from the heatsink outer surface 21. In this case, it is preferable that the heatsink 20 be provided with a recess 23 that fits into the shape of the nut 54, and that the nut 54 be housed in the recess 23.

[0075] The external terminal E1 does not have to be a round terminal. For example, the external terminal E1 may be a terminal having a U-shaped connection portion with the shaft portion 52. In short, the external terminal E1 may be a crimp terminal.

[0076] The input / output terminal 40 may be one or more of a positive input electrode, a negative input electrode, a U-phase output electrode, a V-phase output electrode, and a W-phase output electrode. For example, the configuration of the input / output terminal 40 of the embodiment may be applied only to the input terminal, and the configuration of the output terminal may be different from the configuration of the input / output terminal 40. Furthermore, the configuration of the input / output terminal 40 of the embodiment may be applied only to the output terminal, and the configuration of the input terminal may be different from the configuration of the input / output terminal 40.

[0077] The heat sink 20 does not have to be made of aluminum. The heat sink 20 may be configured to be able to dissipate heat generated in the substrate 30. The power conversion device 10 does not have to be an inverter device. For example, the power conversion device 10 may be a DC / DC converter. The configuration of the components mounted on the substrate 30 may be changed as appropriate depending on the application of the power conversion device 10. Furthermore, the number of input / output terminals 40 may be changed as appropriate depending on the application of the power conversion device 10.

[0078] The elastic member 60 does not have to be press-fitted between both the shaft portion 52 and the heat sink 20 and between the shaft portion 52 and the input / output terminal 40. For example, the elastic member 60 may be press-fitted between the heat sink 20 and the shaft portion 52, but not between the input / output terminal 40 and the shaft portion 52. Furthermore, the elastic member 60 may be press-fitted between the input / output terminal 40 and the shaft portion 52, but not between the heat sink 20 and the shaft portion 52. [Explanation of symbols]

[0079] 10...power conversion device, 10b...bolt insertion hole as through hole, 20...heat sink, 21...heat sink outer surface, 23...recess, 24...resin member, 30...substrate, 40...input / output terminal, 50...fastening member, 51...bolt, 52...shaft portion, 53...flange portion, 54...nut, 60...elastic member, 61...first elastic member, 62...second elastic member, E1...external terminal, L...axis, S...switching element.

Claims

1. A heat sink; a substrate on which a switching element is mounted, the substrate being disposed on the heat sink; an input / output terminal provided upright on the substrate for electrically connecting the substrate to an external terminal, the input / output terminal is connected to the external terminal at one end in an axis extending direction and to the substrate at the other end, a fastening member including a bolt having a shaft portion with a flange portion provided at a base end thereof and a nut threaded onto a tip end of the shaft portion, the shaft portion passing through a through hole formed by the heat sink, the substrate, and the input / output terminal in a direction in which the axis extends; an elastic member press-fitted between at least one of the space between the shaft portion and the heat sink and the space between the shaft portion and the input / output terminal while separating the shaft portion from the heat sink and the input / output terminal; a power conversion device in which the fastening member fastens the heat sink, the input / output terminal, the substrate, and the external terminal in the direction of extension of the axis using the flange portion and the nut, and is held by the elastic member at least one of between the shaft portion and the heat sink and between the shaft portion and the input / output terminal.

2. 2. The power conversion device according to claim 1, wherein the fastening member has a shaft portion inserted into the through hole from an end portion on the heat sink side, the tip portion protruding from the input / output terminal, and the nut abutting against the external terminal.

3. the heat sink has a recess in an outer surface thereof opposite to a surface facing the substrate, the recess being recessed from the outer surface of the heat sink and opening in a direction in which the axis extends; The power conversion device according to claim 1 or 2, wherein the flange portion is housed in the recess.

4. the flange portion has a polygonal shape when viewed in a thickness direction of the flange portion, The power conversion device according to claim 3 , wherein the recess has a polygonal shape in a plan view of the outer surface of the heat sink that engages with the flange portion.

5. 3. The power conversion device according to claim 1, further comprising a resin member interposed between the heat sink and the bolt, the resin member insulating the heat sink from the bolt.

6. 3. The power conversion device according to claim 1, wherein the elastic member comprises a first elastic member arranged in the through hole between the shaft portion and the input / output terminal, and a second elastic member arranged between the bolt and the heat sink.

7. 3. The power conversion device according to claim 1, wherein the elastic member seals at least one of a gap between the shaft portion and the heat sink and a gap between the shaft portion and the input / output terminal.

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