Power converter

Abstract

The present invention provides a power conversion device that can be miniaturized while suppressing the reduction in fastening strength of input / output terminals to the circuit board due to the attachment and detachment of external terminals. [Solution] The power converter 10 includes a heat sink 20, a substrate 40, input / output terminals 50, and an external busbar 60. The input / output terminals 50 are installed on the substrate 40 by a first bolt 71 fastened to the base end of the input / output terminals 50, passing through the heat sink 20 and the substrate 40. The input / output terminals 50 have a tip 52 on the opposite side of the base end in the direction in which the axis L extends. The external busbar 60 is fastened to the input / output terminals 50 and the external terminal E1. The external busbar 60 has a first end 61 fastened to the tip 52 of the input / output terminals 50 by a second bolt 72. The external busbar 60 has a second end located off-axis L. At the second end 62, the external busbar 60 is fastened to the external terminal E1 by a third bolt 73.

Description

Technical Field

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

Background Art

[0002] For example, the power conversion device disclosed in Patent Document 1 includes a heat sink, a substrate, and terminals 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 and the second conductive member are arranged on the axis of the terminal and are electrically connected. The first conductive member constitutes a portion near the base end of the terminal. The first conductive member is fixed to the heat sink by a first screw which is a first bolt screwed into the heat sink. The second conductive member constitutes a portion near the tip end of the terminal. The second conductive member is connected to an external wiring by a second screw which is a second bolt screwed into the second conductive member. The external wiring is electrically connected to the substrate via the terminal.

[0003] Patent Document 1 also discloses a power conversion device having a terminal in which a portion near the base end of the terminal is eccentric with respect to a portion near the tip end. The attachment and detachment of the external terminal from the terminal are performed by rotating the second screw. The terminal is eccentric with respect to the portion near the tip end at the portion near the base end, thereby suppressing the rotation of the first screw by the torque applied when rotating the second screw.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In input / output terminals, if the first bolt at the base and the second bolt at the tip are aligned on the axis of the input / output terminal, rotating the second bolt to attach or detach an external terminal may cause the first bolt to rotate due to the torque involved in that rotation. This may reduce the fastening strength of the input / output terminal to the circuit board.

[0006] Furthermore, if the rotation of the first bolt is suppressed by eccentricating the base portion of the input / output terminal relative to the tip portion, there is a risk that the projected area of ​​the input / output terminal on the circuit board will increase. In other words, there is a risk that the power conversion device will become larger due to the increase in the area of ​​the circuit board. In power conversion devices, it is desirable to miniaturize them while suppressing the decrease in fastening strength of the input / output terminals to the circuit board due to the attachment and detachment of external terminals. [Means for solving the problem]

[0007] A power conversion device for solving the above problems comprises a heat sink, a substrate on which switching elements are mounted and disposed on the heat sink, and input / output terminals erected on the substrate for electrically connecting the substrate to external terminals, wherein the input / output terminals are installed on the heat sink and the substrate by a first bolt fastened to the base end of the input / output terminals while penetrating the heat sink and the substrate, and the tip of the input / output terminal is on the opposite side of the base end in the direction in which the axis of the input / output terminal extends, and the power conversion device comprises an external busbar fastened to the input / output terminal and the external terminal, wherein the first end of the external busbar is fastened to the tip of the input / output terminal by a second bolt, and the second end, which is located off-axis, is fastened to the external terminal by a third bolt.

[0008] According to this configuration, the external busbar is fastened to the input / output terminals at its first end by a second bolt, and to the external terminals at its second end, which is different from the first end, by a third bolt. Furthermore, the first and second bolts are located on the axis of the input / output terminals, while the third bolt is positioned off-axis due to the external busbar. Therefore, when the power converter attaches and detaches the external terminals to the external busbar, the torque related to the screwing and retracting of the third bolt prevents the input / output terminals from rotating relative to the first bolt. As a result, the power converter can prevent the first bolt from rotating in the direction that loosens it as the third bolt rotates.

[0009] Furthermore, the input / output terminals are fastened to the substrate by a first bolt inserted at the base end. For example, consider a case where an external terminal is directly fastened to the tip of the input / output terminal, while the portion of the input / output terminal near the base end is bent to suppress rotation of the input / output terminal relative to the first bolt due to the torque involved in attaching and detaching the external terminal. Compared to this case, the power converter can reduce the projected area of ​​the input / output terminals on the substrate, thus suppressing an increase in the substrate area. In other words, the power converter can suppress the weakening of the fastening between the input / output terminals and the substrate due to the torque involved in attaching and detaching the external terminal without increasing the substrate area. As a result, the power converter can be miniaturized while suppressing the decrease in the fastening strength of the input / output terminals to the substrate due to the attachment and detachment of the external terminal.

[0010] In a power conversion device, the input / output terminal may have a first insertion hole into which the first bolt is inserted, a second insertion hole into which the second bolt is inserted, and a barrier that separates the first insertion hole and the second insertion hole.

[0011] According to this, the first and second insertion holes of the input / output terminals are not in communication within the input / output terminal. By isolating the first and second insertion holes with a barrier, the input / output terminal can prevent fluid flowing in from the tip of the input / output terminal from passing through the inside of the input / output terminal and reaching the substrate. In other words, the power converter can improve its durability by having a barrier in the input / output terminal.

[0012] In a power conversion device, the heat sink has a pair of edges on the surface on which the substrate is placed, the input / output terminals are located near one of the edges, and the external busbar has a first end near one of the edges of the heat sink and a second end near the other edge of the heat sink.

[0013] For example, consider a case where an external busbar is installed for input / output terminals located near one edge of the heatsink, with the second end near one edge of the heatsink and the first end near the other edge. Compared to this case, the power converter with the above configuration can have a longer external busbar so that the entire external busbar and the heatsink overlap when viewed from the direction in which the axis of the input / output terminal extends. In other words, the power converter with the above configuration can prevent the portion of the external busbar near the second end from protruding from the heatsink when viewed from the direction in which the axis of the input / output terminal extends. As a result, the power converter can avoid becoming larger due to the external busbar protruding from the heatsink.

[0014] In a power conversion device, the third bolt preferably has a shaft portion that penetrates the external terminal and the external busbar, and a nut is provided that is screwed onto the shaft portion.

[0015] According to this, the external terminals are fastened to the external busbar by a joint fastening of a third bolt and nut. This allows the power converter to firmly fasten its external terminals to the external busbar.

[0016] In a power conversion device, a cover member is installed on the heat sink, wherein the cover member and the heat sink define a housing space for housing the substrate, with the tip portion penetrating through the cover member, the external terminals and the external busbars are located outside the housing space, and the cover member has a cover recess that is recessed from the outer surface of the cover member for housing the nut.

[0017] According to this, the input / output terminals can be avoided from interfering with the cover member in the direction in which the axial line extends, without extending the input / output terminals in that direction. In other words, the power converter can fasten the external terminals to the external busbar with a third bolt and nut without increasing the size in the direction in which the axial line of the input / output terminals extends.

[0018] Furthermore, the cover member has a recessed area, which prevents the nut removed from the third bolt from falling off the power converter when attaching or detaching the external terminal. As a result, the power converter can make the attachment of the external terminal easier.

[0019] In the power conversion device, it is preferable to further have an insulating member provided on the heat sink and interposed between the flange portion provided on the end of the first bolt and the heat sink, and a sealing member interposed between the insulating member and the heat sink and sealing the space between the insulating member and the heat sink.

[0020] According to this, the power converter can insulate the first volt from the heat sink by insulating members that are separate from the heat sink and the first volt. Therefore, even if the insulation between the heat sink and the first volt deteriorates, the desired insulation can be maintained by replacing the insulating member. In addition, the power converter can prevent fluid passing between the insulating member and the heat sink from reaching the substrate by having a sealing member between them.

[0021] Furthermore, in the power conversion device, since the input / output terminals are fastened to the substrate by the first bolt, the number of insulating members and sealing members can be reduced as compared with, for example, the case where the input / output terminals are fastened to the substrate by a plurality of bolts.

[0022] In the power conversion device, the heat sink has a heat sink recess that recesses from the outer surface of the heat sink, which is the opposite surface of the surface facing the substrate, and opens in a direction in which the axis of the input / output terminal extends. The first bolt may be fastened to the base end while accommodating the flange portion in the heat sink recess.

[0023] According to this, the power conversion device can avoid the first bolt protruding from the outer surface of the heat sink by accommodating the flange portion of the first bolt in the heat sink recess. That is, the power conversion device can suppress the increase in size in the direction in which the axis of the input / output terminal extends due to the first bolt protruding from the heat sink.

Advantages of the Invention

[0024] According to the present invention, it is possible to miniaturize the power conversion device while suppressing a decrease in the fastening strength of the input / output terminals to the substrate due to the attachment and detachment of the external terminals.

Brief Description of the Drawings

[0025] [Figure 1] FIG. 1 is an exploded perspective view showing the power conversion device. [Figure 2] FIG. 2 is an enlarged cross-sectional view showing the power conversion device. [Figure 3] FIG. 3 is a bottom view showing the power conversion device. [Figure 4] FIG. 4 is a top view showing the power conversion device.

Embodiments for Carrying Out the Invention

[0026] The following describes one embodiment of the power conversion device. In this embodiment, the power conversion device is an inverter device mounted on a vehicle. In other words, the power conversion device of this embodiment is supplied with power from a battery mounted on the vehicle, and after converting that power, outputs it to a load mounted on the vehicle.

[0027] <Overall view of the power conversion device> As shown in Figures 1 and 2, the power converter 10 includes a heat sink 20, a cover member 30, a substrate 40, input / output terminals 50, and an external busbar 60. The power converter 10 has multiple input / output terminals 50. The power converter 10 in this embodiment has five input / output terminals 50. The power converter 10 has an external busbar 60 for each input / output terminal 50. Note that in Figure 1, the external busbar 60 for one input / output terminal 50 is shown, and the external busbars 60 for the other input / output terminals 50 are not shown. Also, in Figure 2, the external busbar 60 for only one input / output terminal 50 is shown.

[0028] The heat sink 20 is a rectangular plate when viewed in the thickness direction. The heat sink 20 is made of, for example, aluminum. The heat sink 20 has an outer surface 21 and a mounting surface 22 in the thickness direction.

[0029] As shown in Figure 2, the heatsink 20 has heatsink recesses 23 on its outer surface 21. The heatsink recesses 23 are recesses that are recessed from the outer surface 21. As shown in Figure 3, the heatsink 20 has five heatsink recesses 23 corresponding to the positions where the input / output terminals 50 shown in Figure 1 are located.

[0030] As shown in Figure 2, the heat sink recess 23 opens outwards from the heat sink 20 in the thickness direction of the heat sink 20. As shown in Figure 3, the heat sink 20 has a polygonal shape in a plan view taken from the thickness direction of the heat sink 20. The heat sink recess 23 in this embodiment has a hexagonal shape.

[0031] As shown in Figures 1 and 2, the heat sink recess 23 is provided with a resin member 24 as an insulating member and a first sealing member 25 as a sealing member. The resin member 24 has insulating properties. In a plan view from the thickness direction of the heat sink 20, the resin member 24 has the same shape as the heat sink recess 23. In other words, the resin member 24 in this embodiment is hexagonal. The outer surface of the resin member 24 is in contact with the inner surface of the heat sink recess 23. A through hole is formed in the center of the resin member 24. The first sealing member 25 is positioned between the resin member 24 and the heat sink 20. The first sealing member 25 seals the space between the resin member 24 and the heat sink 20.

[0032] As shown in Figure 1, the mounting surface 22 protrudes slightly at the edges of the heat sink 20. The heat sink 20 has a pair of first edges 22a on the mounting surface 22. The heat sink 20 also has a pair of second edges 22b on the mounting surface 22. The pair of first edges 22a and the pair of second edges 22b are formed by the protrusion of the edges of the mounting surface 22.

[0033] The pair of first edges 22a extend parallel to each other on the mounting surface 22. In the heat sink 20, the substrate 40 and the multiple input / output terminals 50 are positioned closer to one of the first edges 22a. The pair of second edges 22b extend parallel to each other and perpendicular to the pair of first edges 22a on the mounting surface 22.

[0034] Hereafter, the direction in which each first edge portion 22a extends will be referred to as the first direction A1, and the direction in which each second edge portion 22b extends will be referred to as the second direction A2. The first direction A1 is perpendicular to the second direction A2.

[0035] As shown in Figure 2, the heatsink 20 has a protrusion 26 on the mounting surface 22. The protrusion 26 is a portion that slightly protrudes from the mounting surface 22 in the thickness direction of the heatsink 20. The protrusion 26 is aligned with the heatsink recess 23 in the thickness direction of the heatsink 20. The heatsink 20 has a through hole that communicates with the heatsink recess 23 and penetrates the protrusion 26. The heatsink 20 has the protrusion 26 at the position where the input / output terminals 50 shown in Figure 1 are located.

[0036] As shown in Figure 1, the cover member 30 is installed on the mounting surface 22. The cover member 30 and the heat sink 20 define the housing space 10a shown in Figure 2. The cover member 30 is connected to a pair of first edges 22a and a pair of second edges 22b of the heat sink 20.

[0037] The cover member 30 has four side plates 31 and a top plate 32. The side plates 31 are erected on the heat sink 20. The top plate 32 is connected to the end of each of the four side plates 31 opposite to the end connected to the heat sink 20. The heat sink 20, the four side plates 31, and the top plate 32 define the housing space 10a shown in Figure 2. The top plate 32 is provided with terminal holes 32a through which the input / output terminals 50 pass. The top plate 32 has five terminal holes 32a corresponding to the five input / output terminals 50. The five terminal holes 32a are located near one edge of the top plate 32 in the second direction A2.

[0038] The cover member 30 has a cover recess 34. The cover recess 34 is formed in the top plate 32. The cover recess 34 is a portion of the cover member 30 that is recessed from the outer surface of the cover member 30. More specifically, the cover recess 34 is formed on the side of the top plate 32 opposite to the side facing the heat sink 20, and is a portion that is recessed from that opposite side. The cover recess 34 is polygonal when viewed from the thickness direction of the top plate 32. In this embodiment, the cover recess 34 is hexagonal when viewed from the thickness direction of the top plate 32.

[0039] As shown in Figures 1 and 2, the substrate 40 is a long plate. The substrate 40 is placed on the heat sink 20. The substrate 40 is placed on the mounting surface 22 with multiple protrusions 26 resting on it. In other words, the mounting surface 22 is the surface of the heat sink 20 that faces the substrate 40. The outer surface 21 of the heat sink is the surface of the heat sink 20 opposite to the surface facing the substrate 40. The substrate 40 is placed on the mounting surface 22, near one of the first edges 22a in the second direction A2. The substrate 40 is placed on the heat sink 20 with a slight gap between it and the mounting surface 22 due to the protrusions 26. The substrate 40 is housed in the housing space 10a.

[0040] Multiple switching elements S are mounted on the substrate 40. The multiple switching elements S are provided on the surface of the substrate 40 facing the mounting surface 22. The multiple switching elements S are arranged in the gap formed by the protrusion 26 between the heat sink 20 and the substrate 40. Multiple capacitors C are erected on the surface of the substrate 40 opposite to the surface on which the multiple switching elements S are installed.

[0041] <Input / output terminal> As shown in Figure 1, the input / output terminals 50 are cylindrical. The input / output terminals 50 are mounted upright on the substrate 40. The input / output terminals 50 are located on the side of the substrate 40 where multiple capacitors C are mounted. The five input / output terminals 50 are clustered together towards one of the first edges 22a in the second direction A2.

[0042] The input / output terminal 50 is connected to the substrate 40 at its base end 51. The input / output terminal 50 has a tip 52 on the side opposite to the base end 51 in the direction in which the axis L of the input / output terminal 50 extends. The input / output terminal 50 is provided on the substrate 40 in the direction in which the axis L extends, in a portion adjacent to the heat sink recess 23 and the protrusion 26. The input / output terminal 50 is connected to the substrate 40 in the housing space 10a.

[0043] As shown in Figure 2, the input / output terminal 50 is inserted through the terminal hole 32a of the top plate 32. In other words, the cover member 30 allows the input / output terminal 50 to pass through. The input / output terminal 50 has a second sealing member 33 near its tip 52. The second sealing member 33 seals the space between the top plate 32 and the input / output terminal 50.

[0044] The input / output terminal 50 has a first insertion hole 50a and a second insertion hole 50b. The first insertion hole 50a is open at the base end 51 of the input / output terminal 50. The second insertion hole 50b is open at the tip end 52 of the input / output terminal 50. Female threads are formed on the inner circumferential surfaces of the first insertion hole 50a and the second insertion hole 50b.

[0045] The input / output terminal 50 has a blocking section 50c. The blocking section 50c is located in the center of the input / output terminal 50 in the direction in which the axis L extends. The blocking section 50c is interposed between the first insertion hole 50a and the second insertion hole 50b in the direction in which the axis L extends. The blocking section 50c separates the first insertion hole 50a and the second insertion hole 50b. The first insertion hole 50a and the second insertion hole 50b are not in communication inside the input / output terminal 50 due to the blocking section 50c.

[0046] The input / output terminals 50 are attached to the heat sink 20 and the substrate 40 by a first bolt 71. The first bolt 71 has a first shaft portion 71a with a male thread formed on it, and a first flange portion 71b which is a flange portion. The first flange portion 71b is provided at one end of the first shaft portion 71a.

[0047] The first bolt 71 is fastened to the base end 51 of the input / output terminal 50 while passing through the heat sink 20 and the substrate 40. More specifically, the first bolt 71 has a first flange portion 71b housed in the heat sink recess 23, while the first shaft portion 71a penetrates the heat sink 20 and the substrate 40. The first flange portion 71b is housed in the heat sink recess 23 with a resin member 24 interposed between the first flange portion 71b and the heat sink 20. The portion of the first shaft portion 71a that penetrates the heat sink 20 and the substrate 40 is inserted into the first insertion hole 50a. The end of the first shaft portion 71a is screwed into the input / output terminal 50.

[0048] The input / output terminal 50 consists of two input-side terminals located near two edges in the longitudinal direction of the substrate 40, and an output-side terminal located closer to the interior of the substrate 40 than the input-side terminals in the longitudinal direction of the substrate 40. The input-side terminal consists of a positive input electrode and a negative input electrode. The output-side terminal consists of a U-phase output electrode, a V-phase output electrode, and a W-phase output electrode.

[0049] Hereafter, 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 the input / output terminal 50. In other words, the configuration of the input / output terminal 50 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.

[0050] <External busbar> As shown in Figures 1 and 2, the external busbar 60 is a long, plate-shaped body attached to the tip 52 of the input / output terminal 50. The external busbar 60 is located outside the housing space 10a. The external busbar 60 is made of metal. The external busbar 60 has a first end 61 and a second end 62 in the longitudinal direction.

[0051] The external busbar 60 is connected to the tip 52 of the input / output terminal 50 at its first end 61. More specifically, the first end 61 of the external busbar 60 is connected to the portion of the input / output terminal 50 that penetrates the cover member 30 and protrudes outside the housing space 10a. The first end 61 of the external busbar 60 lies on the axis L of the input / output terminal 50.

[0052] A second bolt 72 passes through the first end 61 of the external busbar 60. The first end 61 is fastened to the tip 52 of the input / output terminal 50 by the second bolt 72. The central axis of the second bolt 72 coincides with axis L.

[0053] The second bolt 72 has a second shaft portion 72a with a male thread formed on it, and a second flange portion 72b. The second shaft portion 72a is inserted into the second insertion hole 50b while passing through the external busbar 60. The second bolt 72 is fastened to the input / output terminal 50 by screwing the second shaft portion 72a to the input / output terminal 50. The second bolt 72 fastens the external busbar 60 to the input / output terminal 50 and also presses the external busbar 60 against the tip portion 52 of the input / output terminal 50 with the second flange portion 72b.

[0054] The external busbar 60 is connected to the input / output terminals 50 at its first end 61 and extends in the second direction A2. The second end 62 is located off-axis L. The external busbar 60 has its first end 61 near the edge of the heatsink 20 and its second end 62 closer to the center of the heatsink 20 than the edge. More specifically, the external busbar 60 has its first end 61 near the first edge 22a of a pair of first edges 22a that is closer to the input / output terminals 50 in the second direction A2. The external busbar 60 also has its second end 62 near a different first edge 22a.

[0055] The external busbar 60 is connected to the external terminal E1 at its second end 62. The external terminal E1 is a ring terminal. The external terminal E1 is located outside the housing space 10a. The external terminal E1 is provided at the end of the external wiring E2. The external wiring E2 is connected to the external terminal E1 at one end and to a battery (not shown) or a load (not shown) at the other end. The external busbar 60 electrically connects the battery or load and the input / output terminal 50 via the external terminal E1.

[0056] The external busbar 60 is fastened at its second end 62 to the external terminal E1 by a third bolt 73. In other words, the external busbar 60 is fastened to the input / output terminal 50 and the external terminal E1. The central axis of the third bolt 73 is parallel to axis L. The third bolt 73 is not on axis L. In other words, the central axis of the third bolt 73 does not coincide with axis L.

[0057] The third bolt 73 has a third shaft portion 73a, which is the shaft portion, and a third flange portion 73b. The third bolt 73 penetrates the second end 62 of the external busbar 60 and the external terminal E1 by the third shaft portion 73a. In other words, the third shaft portion 73a penetrates the external terminal E1 and the external busbar 60. The third flange portion 73b of the third bolt 73 is in contact with the surface of the external busbar 60 that is opposite to the surface that contacts the input / output terminal 50, among the surfaces that the external busbar 60 has in the thickness direction.

[0058] A nut 73c is provided on the third bolt 73. The nut 73c is screwed onto the third shaft portion 73a of the third bolt 73, which passes through the external terminal E1 and the external busbar 60. The nut 73c is housed in the cover recess 34.

[0059] The nut 73c engages with the cover recess 34. More specifically, the nut 73c has an outer surface that engages with the inner surface of the cover recess 34. The nut 73c has a polygonal cross-section. In this embodiment, the cross-sectional shape of the nut 73c is hexagonal. As a result, the nut 73c is housed in the cover recess 34 in a way that prevents it from rotating.

[0060] Note that in Figure 1, only one of the multiple input / output terminals 50 is shown, and the first bolt 71, second bolt 72, third bolt 73, nut 73c, external busbar 60, external terminal E1, and external wiring E2 are illustrated.

[0061] <Operation of a power converter> The power converter 10 supplies power input from the external terminal E1 to the circuit board 40 via the external busbar 60 and the input terminal of the input / output terminal 50. In other words, the input / output terminal 50 is mounted on the circuit board 40 to electrically connect the circuit board 40 to the external terminal E1. The power input to the power converter 10 is supplied from a battery (not shown) through external wiring E2. The power converter 10 converts the input DC power into AC power by the switching operation of a plurality of switching elements S mounted on the circuit board 40, and then outputs it to a load (not shown). In this embodiment, the power converter 10 converts the DC power input to the positive electrode and the negative electrode into AC power on the circuit board 40, and then outputs it to the vehicle load from the U-phase output electrode, V-phase output electrode, and W-phase output electrode. The heat generated on the circuit board 40 by this conversion is dissipated to the outside of the power converter 10 via the heat sink 20.

[0062] The work of attaching the external terminal E1 to the power converter 10 and removing the external terminal E1 from the power converter 10 is performed by applying a predetermined torque to the third bolt 73. In other words, the torque for the above attachment and removal is applied at a position off the axis L of the input / output terminal 50. For this reason, the work of attaching and detaching the external terminal E1 to the external busbar 60 is performed without applying torque to the first bolt 71 that fastens the input / output terminal 50 to the heat sink 20 and the circuit board 40.

[0063] [Effects of this embodiment] The effects of this embodiment will be explained along with their operation. (1) The external busbar 60 is fastened to the input / output terminal 50 at its first end 61 by a second bolt 72, and to the external terminal E1 at its second end 62, which is different from the first end 61, by a third bolt 73. In other words, the first bolt 71 and the second bolt 72 are located on the axis L of the input / output terminal 50, while the third bolt 73 is located off the axis L due to the external busbar 60. Therefore, when the power converter 10 attaches or detaches the external terminal E1 to the external busbar 60, the torque related to the screwing of the third bolt 73 prevents the input / output terminal 50 from rotating relative to the first bolt 71. As a result, the power converter 10 can prevent the first bolt 71 from rotating in the direction that loosens it as the third bolt 73 rotates.

[0064] Furthermore, the input / output terminals 50 are fastened to the substrate 40 by a first bolt 71 inserted into the base end 51. For example, consider a case where the external terminal E1 is directly fastened to the tip 52 of the input / output terminal 50, while the portion near the base end 51 is bent to suppress rotation of the input / output terminal 50 relative to the first bolt 71 due to the torque involved in attaching and detaching the external terminal E1. Compared to this case, the power converter 10 can reduce the projected area of ​​the input / output terminals 50 on the substrate 40. This makes it possible to suppress weakening of the fastening between the input / output terminals 50 and the substrate 40 due to the torque involved in attaching and detaching the external terminal E1 without increasing the area of ​​the substrate 40. As a result, the power converter 10 can be miniaturized while suppressing the decrease in the fastening strength of the input / output terminals 50 to the substrate 40 due to the attachment and detachment of the external terminal E1.

[0065] (2) The first insertion hole 50a and the second insertion hole 50b of the input / output terminal 50 are not in communication inside the input / output terminal 50. By isolating the first insertion hole 50a and the second insertion hole 50b with the blocking part 50c, the input / output terminal 50 can prevent fluid flowing in from the tip 52 of the input / output terminal 50 from passing through the inside of the input / output terminal 50 and reaching the substrate 40. In other words, the power converter 10 can improve durability by having the blocking part 50c in the input / output terminal 50.

[0066] (3) As shown in Figure 4, when the power converter 10 is viewed from the direction in which the axis L of the input / output terminal 50 extends, the entire external busbar 60 overlaps with the heatsink 20. For example, consider the case where the input / output terminal 50 is located near one of the first edges 22a, and the external busbar 60 is installed such that the second end 62 is near one of the first edges 22a of the heatsink 20 and the first end 61 is near the other first edge 22a of the heatsink 20. Compared to this case, the power converter 10 can have a longer external busbar 60 such that the entire external busbar 60 overlaps with the heatsink 20 when viewed from the direction in which the axis L extends. In other words, the power converter 10 can prevent the portion of the external busbar 60 near the second end 62 from protruding from the heatsink 20 when viewed from the direction in which the axis L extends. As a result, the power converter 10 can prevent the external busbar 60 from becoming larger due to the external busbar 60 protruding from the heatsink 20.

[0067] (4) The external terminal E1 is fastened to the external busbar 60 by fastening together the third bolt 73 and the nut 73c. ​​This allows the power converter 10 to firmly fasten the external terminal E1 to the external busbar 60.

[0068] (5) The cover member 30 accommodates the nut 73c in the cover recess 34. This allows the power converter 10 to avoid the nut 73c interfering with the cover member 30 in the direction in which the input / output terminals 50 extend without extending the input / output terminals 50. In other words, the power converter 10 can fasten the external terminal E1 to the external busbar 60 with the third bolt 73 and nut 73c without increasing the size in the direction in which the input / output terminals 50 extend along the axis L.

[0069] (6) The cover member 30 has a cover recess 34, which prevents the nut 73c that has been removed from the third bolt 73 from falling off the power converter 10 when attaching or detaching the external terminal E1. As a result, the power converter 10 can make the installation of the external terminal E1 easier.

[0070] (7) The nut 73c engages with the cover recess 34 and is housed in the cover recess 34 in a way that prevents it from rotating. Therefore, an operator screwing the third bolt 73 and the nut 73c can do so by rotating the third bolt 73 against the nut 73c installed in the cover recess 34. For example, compared to a case where the nut 73c is rotatable inside the cover recess 34, the power converter 10 makes it easier to screw the third bolt 73 and the nut 73c.

[0071] (8) The power converter 10 can insulate the first bolt 71 from the heat sink 20 by a resin member 24 which is separate from the heat sink 20 and the first bolt 71. Therefore, even if the insulation between the heat sink 20 and the first bolt 71 deteriorates, the desired insulation can be maintained by replacing the resin member 24. In addition, the power converter 10 has a first sealing member 25 between the resin member 24 and the heat sink 20, which can prevent fluid that has passed between them from reaching the substrate 40.

[0072] Furthermore, in the power converter 10, since the input / output terminals 50 are fastened to the substrate 40 by the first bolt 71, the number of resin members 24 and first sealing members 25 can be reduced compared to, for example, the case where the input / output terminals 50 are fastened to the substrate 40 by multiple bolts.

[0073] (9) The power converter 10 can avoid the first bolt 71 protruding from the outer surface 21 of the heat sink by housing the first flange portion 71b of the first bolt 71 in the heat sink recess 23. In other words, the power converter 10 can suppress the increase in size in the direction in which the axis L extends due to the first bolt 71 protruding from the heat sink 20.

[0074] [Example of changes] The above embodiment can be implemented with the following modifications. The above embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0075] ○ The heat sink 20 does not necessarily have a heat sink recess 23. In this case, it is preferable that the heat sink 20 is configured such that the first flange portion 71b protruding from the outer surface 21 of the heat sink does not interfere with the installation location of the power converter 10. For example, the power converter 10 may have legs on the outer surface 21 of the heat sink, and may be installed such that the outer surface 21 of the heat sink is spaced apart from the installation location by these legs.

[0076] ○ The power converter 10 does not necessarily have to have a resin member 24. In this case, for example, insulation is applied between the heat sink 20 and the first bolt 71. In short, it is sufficient that the heat sink 20 and the first bolt 71 are insulated from each other.

[0077] ○ The power converter 10 does not necessarily have a first sealing member 25 between the resin member 24 and the heat sink 20. For example, the power converter 10 may have a first sealing member 25 between the heat sink 20 and the first shaft portion 71a.

[0078] ○ The cover recess 34 does not necessarily have to be engaged with the nut 73c. ​​For example, the cover recess 34 may accommodate the nut 73c while maintaining a distance between its inner surface and the outer surface of the nut 73c.

[0079] ○ The cover member 30 does not necessarily have to have a cover recess 34. In this case, the length of the input / output terminal 50 is adjusted so that the nut 73c and the top plate 32 of the cover member 30 do not come into contact.

[0080] ○ The third bolt 73 does not necessarily have to be fitted with a nut 73c. ​​For example, a female thread that can be screwed onto the third bolt 73 may be provided on the inner circumferential surface of the cover recess 34. Alternatively, a female thread may be provided on the portion of the external busbar 60 through which the third shaft portion 73a is inserted, and the third bolt 73 may be screwed onto the external busbar 60.

[0081] ○ The direction in which the external busbar 60 extends in the power converter 10 is not limited to that of the embodiment. Also, the external busbar 60 may have a portion that does not overlap with the top plate 32 when viewed from the thickness direction of the external busbar 60.

[0082] ○ The external busbar 60 does not have to be a long plate-like body. For example, the external busbar 60 may have an L-shape when viewed from the thickness direction, with the portion closer to the first end 61 bent relative to the portion closer to the second end 62.

[0083] ○ The input / output terminal 50 does not necessarily have a blocking portion 50c. In other words, the first insertion hole 50a and the second insertion hole 50b may be in communication inside the input / output terminal 50. In this case, for example, a sealing member is provided between the input / output terminal 50 and the substrate 40, or between the input / output terminal 50 and the second flange portion 72b.

[0084] ○ The external terminal E1 does not have to be a ring terminal. For example, the external terminal E1 may be a terminal with a U-shaped connection to the third shaft portion 73a. In short, the external terminal E1 can be any crimp terminal.

[0085] ○ The input / output terminal 50 may be one or more of the positive input electrode, negative input electrode, U-phase output electrode, V-phase output electrode, and W-phase output electrode. For example, the configuration of the input / output terminal 50 in this embodiment may apply only to the input terminal, and the configuration of the output terminal may differ from that of the input / output terminal 50.

[0086] ○ The heat sink 20 does not have to be made of aluminum. The heat sink 20 just needs to be configured to dissipate the heat generated on the circuit board 40. ○ The power converter 10 does not have to be an inverter device. For example, the power converter 10 may be a DC / DC converter. The configuration of components mounted on the circuit board 40 is appropriately changed according to the application of the power converter 10. Also, the number of input / output terminals 50 is appropriately changed according to the application of the power converter 10.

[0087] [Note] The technical concepts that can be understood from the above embodiments and modified examples are described below. <Note 1> The nut engages with the recess in the cover of the power conversion device. [Explanation of symbols]

[0088] 10...Power converter, 10a...Housing space, 20...Heat sink, 21...Heat sink outer surface, 22a...First edge as edge, 23...Heat sink recess, 24...Resin member as insulating member, 25...First sealing member as sealing member, 30...Cover member, 34...Cover recess, 40...Substrate, 50...Input / output terminals, 50a...First insertion hole, 50b...Second insertion hole, 50c...Blocking part, 51...Base end, 52...Tip, 60...External busbar, 61...First end, 62...Second end, 71...First bolt, 71b...First flange as flange, 72...Second bolt, 73...Third bolt, 73a...Third shaft as shaft, 73c...Nut, E1...External terminal, L...Axis, S...Switching element.

Claims

1. heatsink and A circuit board is placed on the heat sink and has switching elements mounted on it, The board has input / output terminals erected on it for electrically connecting to external terminals, The input / output terminal is installed on the substrate by a first bolt fastened to the base end of the input / output terminal, penetrating the heat sink and the substrate, and the power conversion device has a tip portion on the opposite side of the base end in the direction in which the axis of the input / output terminal extends, It has an external busbar that is fastened to the input / output terminals and the external terminal, A power converter in which the external busbar has a first end fastened to the tip of the input / output terminal by a second bolt, and the second end, which is located off-axis, fastened to the external terminal by a third bolt.

2. The aforementioned input / output terminals are, The first insertion hole into which the first bolt is inserted, The second insertion hole into which the second bolt is inserted, The power conversion device according to claim 1, further comprising a blocking section that separates the first insertion hole and the second insertion hole.

3. The heat sink has a pair of edges on the surface on which the substrate is placed. The input / output terminals are located in the portion closer to one of the edges, The power conversion device according to claim 1 or claim 2, wherein the external busbar has the first end near one edge of the heat sink and the second end near the other edge of the heat sink.

4. The power conversion device according to claim 1 or claim 2, wherein the third bolt has a shaft portion that penetrates the external terminal and the external busbar, and a nut is screwed onto the shaft portion.

5. A cover member installed on the heat sink, wherein the cover member and the heat sink define a housing space for housing the substrate, with the cover member penetrating the tip portion. The external terminals and external busbars are located outside the housing space. The power conversion device according to claim 4, wherein the cover member has a cover recess that is recessed from the outer surface of the cover member and accommodates the nut.

6. The heat sink is provided with an insulating member interposed between the flange portion provided at the end of the first bolt and the heat sink, The power conversion device according to claim 1 or claim 2, further comprising a sealing member interposed between the insulating member and the heat sink, and sealing the space between the insulating member and the heat sink.

7. The heat sink has a heat sink recess on the outer surface of the heat sink, which is the surface opposite 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 of the input / output terminal extends. The power conversion device according to claim 6, wherein the first bolt is fastened to the base end while housing the flange portion in the heat sink recess.

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