Cooler and power converter

Abstract

The present invention provides a cooler and a power converter in which the decrease in refrigerant flow velocity is suppressed. [Solution] The case is provided with a second refrigerant passage 720 that connects a first refrigerant passage 710 extending in the Y direction and a third refrigerant passage 730 extending in the X direction. The third refrigerant passage is located above the first refrigerant passage in the Z direction and spaced apart in the Y direction. The second refrigerant passage is divided by a second bottom surface through which a first communication hole 751 into which refrigerant from the first refrigerant passage flows, a second top surface located above the second bottom surface in the Z direction and through which a second communication hole 752 into which refrigerant flows out to the third refrigerant passage opens, and a second annular surface connecting these. A part of the second annular surface is a slope in which, as you approach the second communication hole from the first communication hole in the Y direction, the distance in the Z direction from the second communication hole gradually decreases. This slope and the first communication hole are aligned in the Y direction. Also, the second communication hole is longer in the Y direction than in the X direction.

Description

Technical Field

[0001] The disclosure described in this specification relates to a cooler and a power conversion device.

Background Art

[0002] Patent Document 1 discloses an electric work vehicle including a cooling path for cooling an inverter.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the electric work vehicle of Patent Document 1, a refrigerant flows through a hollow portion inside the cooling path. The refrigerant flows through the cooling path by an electric pump. The refrigerant flows in the extending direction of the cooling path, but when the extending direction is changed from the straight direction, the refrigerant collides with the wall surface partitioning the cooling flow path. Thereby, the flow velocity of the refrigerant decreases.

[0005] An object of the present disclosure is to provide a cooler and a power conversion device in which a decrease in the flow velocity of a refrigerant is suppressed.

Means for Solving the Problems

[0006] The cooler according to the disclosed aspect is a cooler including a communication flow path (720) that communicates a first cooling flow path (710) for cooling a first component (521) included in a power conversion circuit (500) and a second cooling flow path (730) for cooling a second component (543) included in the power conversion circuit, the first cooling flow path and the second cooling flow path extend in a vertical direction orthogonal to the vertical direction, the second cooling flow path is located above the first cooling flow path in the vertical direction and is separated from the first cooling flow path in the vertical direction, The connecting passage is divided by connecting surfaces (725, 726, 727) that connect an inlet (751) into which the refrigerant flowing through the first cooling passage flows, and an outlet (752) located vertically above the inlet and spaced vertically apart, which allows the refrigerant that flowed into the inlet to flow out into the second cooling passage. A portion of the connecting surface is a slope (726c) in which the vertical distance from the outlet gradually changes as you approach the outlet from the inlet in the longitudinal direction. The outlet is longer in the vertical direction than in the horizontal direction, which is perpendicular to both the vertical and longitudinal directions.

[0007] The power conversion device in the disclosed embodiment includes a power conversion circuit (500) and A power conversion device having a cooler (600) for cooling a power conversion circuit, The power conversion circuit has a first component (521) and a second component (543), The cooler includes a first cooling channel (710) for cooling a first component, a second cooling channel (730) for cooling a second component, and a connecting channel (720) that connects the first cooling channel and the second cooling channel. The first and second cooling channels extend in a vertical direction perpendicular to the vertical direction. The second cooling channel is located vertically above the first cooling channel and is spaced apart from the first cooling channel in the vertical direction. The connecting passage is divided by connecting surfaces (725, 726, 727) that connect an inlet (751) into which the refrigerant flowing through the first cooling passage flows, and an outlet (752) located vertically above the inlet and spaced vertically apart, which allows the refrigerant that flowed into the inlet to flow out into the second cooling passage. A portion of the connecting surface is a slope (726c) in which the vertical distance from the outlet gradually changes as you approach the outlet from the inlet in the longitudinal direction. The outlet is longer in the vertical direction than in the horizontal direction, which is perpendicular to both the vertical and longitudinal directions.

[0008] According to this, the flow direction of the refrigerant flowing vertically through the first cooling channel (710) is changed to the vertical direction, allowing the refrigerant to flow into the second cooling channel (730) which extends vertically. Due to the shape of the slope (726c), the decrease in the flow velocity of the refrigerant due to collision is suppressed. Due to the shape of the outlet (752), it becomes easier to make the refrigerant that has flowed through the slope (726c) flow vertically. This makes it easier to make the refrigerant flow into the second cooling channel (730) which extends vertically. As a result, the decrease in the flow velocity of the refrigerant flowing into the second cooling channel (730) is suppressed.

[0009] The reference numbers in parentheses above merely indicate the correspondence with the configurations described in the embodiments below, and do not limit the technical scope in any way. [Brief explanation of the drawing]

[0010] [Figure 1] This is a circuit diagram used to explain an in-vehicle system. [Figure 2] This is a perspective view illustrating the case and the refrigerant passages. [Figure 3] This is a cross-sectional view along line III-III in Figure 2. [Figure 4] This is a cross-sectional view along the line IV-IV in Figure 2. [Figure 5] This is a schematic perspective diagram illustrating the refrigerant passage. [Figure 6] This is a schematic top view diagram illustrating the refrigerant passages. [Figure 7] This is a top view illustrating the third refrigerant passage. [Figure 8] This is a partial cross-sectional view of the case and refrigerant passage. [Figure 9] This is a schematic diagram showing the design area. [Figure 10] This is a schematic diagram showing the flow region. [Figure 11] This is a schematic diagram showing the flow region. [Figure 12] This is a schematic diagram showing the flow region. [Figure 13] This is a schematic diagram showing the flow region. [Figure 14]It is a schematic diagram showing a flow region. [Figure 15] It is a schematic diagram showing a flow region. [Figure 16] It is a schematic diagram showing a flow region. [Figure 17] It is a schematic diagram showing a flow region. [Figure 18] It is a schematic diagram showing a flow region. [Figure 19] It is a schematic diagram showing a flow region.

Embodiments for Carrying Out the Invention

[0011] Hereinafter, a plurality of embodiments for implementing the present disclosure will be described while referring to the drawings. In parts corresponding to those described in the previous embodiments, the same reference numerals may be given in the following embodiments and redundant descriptions may be omitted. When only a part of the configuration is described in each embodiment, the description of the other parts of the configuration in the previous embodiment can be applied.

[0012] Combinations are possible between parts that are explicitly shown to be combinable in each embodiment. Also, unless there is a particular obstacle to combination, combinations are possible between a plurality of embodiments, an embodiment and a modification, and between a plurality of modifications, even if not explicitly shown to be combinable.

[0013] Hereinafter, three directions that are orthogonal to each other are shown as the X direction, the Y direction, and the Z direction. The X direction, the Y direction, and the Z direction are linear directions. In the drawings, the description of "direction" is omitted and only X, Y, and Z are illustrated. Also, the flow direction of the refrigerant described later is shown by solid arrows in the drawings.

[0014] When this disclosure is mounted on a vehicle, the X direction is aligned with the left-right direction of the vehicle. The Y direction is aligned with the vehicle's forward and backward direction. The Z direction is aligned with the vehicle's up-down direction. When the vehicle is stationary on a horizontal plane, the plane defined by the X and Y directions is aligned with the horizontal direction. The Z direction is aligned with the vertical direction. Hereinafter, embodiments will be described assuming that the plane defined by the X and Y directions is aligned with the horizontal direction and the Z direction is aligned with the vertical direction. The X direction corresponds to the lateral direction. The Y direction corresponds to the vertical direction.

[0015] <First Embodiment> <In-vehicle systems> First, based on Figure 1, we will outline the in-vehicle system 100 to which the power converter 300 is applied. This in-vehicle system 100 constitutes a system for an electric vehicle. The in-vehicle system 100 includes a battery 200, a power converter 300, and a motor 400.

[0016] Furthermore, the in-vehicle system 100 has multiple ECUs (not shown). These multiple ECUs transmit and receive signals to each other via bus wiring. The multiple ECUs cooperate to control the electric vehicle. The powering and regeneration of the motor 400 are controlled according to the State of Charge (SOC) of the battery 200 by the control of the multiple ECUs. ECU stands for electronic control unit. SOC stands for state of charge.

[0017] An ECU comprises at least one arithmetic processing unit (CPU) and at least one memory device (MMR) as a recording medium for recording programs and data. The ECU is provided by a microcomputer equipped with a computer-readable recording medium. The recording medium is a non-transitional tangible recording medium that non-temporarily stores computer-readable programs. The recording medium may be provided by semiconductor memory or a magnetic disk, etc.

[0018] Battery 200 has multiple secondary batteries. These secondary batteries form a battery stack connected in series. The state of charge (SOC) of this battery stack corresponds to the state of charge (SOC) of battery 200. As secondary batteries, solid-state batteries, lithium-ion secondary batteries, nickel-metal hydride secondary batteries, and organic radical batteries can be used.

[0019] The power converter 300 performs power conversion between the battery 200 and the motor 400. The power converter 300 converts the DC power from the battery 200 into AC power. The power converter 300 converts the AC power generated by the motor 400's power generation (regeneration) into DC power.

[0020] Motor 400 is connected to the axle of an electric vehicle (not shown). The rotational energy (power) of motor 400 is transmitted to the wheels of the electric vehicle via the axle. Conversely, the rotational energy of the wheels is transmitted to motor 400 via the axle.

[0021] The motor 400 is powered by alternating current (AC) electricity supplied from the power converter 300. This provides propulsion to the wheels. The motor 400 also regenerates energy from the rotational energy transmitted from the wheels. The AC electricity generated by this regeneration is converted into DC electricity by the power converter 300. This DC electricity is supplied to the battery 200 and various electrical loads installed in the electric vehicle.

[0022] <Power converter> Next, the power converter 300 will be described. The power converter 300 has a power conversion circuit 500 and a case 600. The power conversion circuit 500 has the components shown in Figure 1. The case 600 has the components shown in Figure 2.

[0023] The components of the power conversion circuit 500 are housed in a case 600. The case 600 is equipped with a refrigerant passage 700 through which the refrigerant passes. The refrigerant passing through this refrigerant passage 700 suppresses the temperature rise of the power conversion circuit 500. The case 600 acts as a cooler.

[0024] <Power Conversion Circuit> The power conversion circuit 500 includes an inverter 510. The inverter 510 converts the DC power from the battery 200 into AC power. This AC power is supplied to the motor 400. The inverter 510 also converts the AC power generated by the motor 400 into DC power. This DC power is supplied to the battery 200. The power conversion circuit 500 may also include a converter that boosts or lowers the input voltage before outputting it.

[0025] The power conversion circuit 500 has an N busbar 501 and a P busbar 502. The battery 200 is connected to these N busbars 501 and P busbars 502. The N busbar 501 is connected to the negative terminal of the battery 200. The P busbar 502 is connected to the positive terminal of the battery 200.

[0026] Furthermore, the power conversion circuit 500 has a U-phase busbar 503, a V-phase busbar 504, and a W-phase busbar 505. The inverter 510 and the motor 400 are electrically connected via these U-phase busbars 503, V-phase busbars 504, and W-phase busbars 505. In Figure 1, the connection points of the various busbars are indicated by white circles. These connection points are electrically connected, for example, by bolts or welding.

[0027] <Inverter> The inverter 510 has a smoothing capacitor 520 and a switch group 530. The N busbar 501 and the P busbar 502 are electrically connected to the smoothing capacitor 520 and the switch group 530.

[0028] The smoothing capacitor 520 is housed in a capacitor case 521. The capacitor case 521 is made of an insulating resin material. Parts of the N busbar 501 and the P busbar 502 are housed in the capacitor case 521. This capacitor case 521 is fixed to the case 600.

[0029] The switch group 530 comprises a U-phase switch module 531, a V-phase switch module 532, and a W-phase switch module 533. These three-phase switch modules have a high-side switch 541 and a low-side switch 542. The three-phase switch modules also have a high-side diode 541a and a low-side diode 542a.

[0030] The switches and diodes of the three-phase switch module are housed in a switch case 543. The switch case 543 is made of an insulating resin material. In this embodiment, the switches and diodes of the three-phase switch module are housed in one switch case 543. Of course, it is also possible to adopt a configuration in which the switches and diodes of the three-phase switch module are individually housed in three switch cases 543.

[0031] In this embodiment, n-channel IGBTs are used as the high-side switch 541 and the low-side switch 542. As shown in Figure 1, the emitter electrode of the high-side switch 541 and the collector electrode of the low-side switch 542 are connected. This connects the high-side switch 541 and the low-side switch 542 in series.

[0032] Furthermore, the cathode electrode of the high-side diode 541a is connected to the collector electrode of the high-side switch 541. The anode electrode of the high-side diode 541a is connected to the emitter electrode of the high-side switch 541. As a result, the high-side diode 541a is connected in antiparallel to the high-side switch 541.

[0033] Similarly, the cathode electrode of the low-side diode 542a is connected to the collector electrode of the low-side switch 542. The anode electrode of the low-side diode 542a is connected to the emitter electrode of the low-side switch 542. As a result, the low-side diode 542a is connected in antiparallel to the low-side switch 542.

[0034] As described above, the switch is housed in the switch case 543. From this switch case 543, the tip of the collector terminal 540a, which is connected to the collector electrode of the high-side switch 541, and the tip of the output terminal 540b, which is connected to the midpoint between the high-side switch 541 and the low-side switch 542, are exposed. Also, from the switch case 543, the tip of the emitter terminal 540c, which is connected to the emitter electrode of the low-side switch 542, and the tip of the gate terminal 540d, which is connected to the gate electrodes of the high-side switch 541 and the low-side switch 542, are exposed.

[0035] As shown in Figure 1, the collector terminal 540a is connected to the P busbar 502. The emitter terminal 540c is connected to the N busbar 501. Due to these electrical connections, the high-side switch 541 and the low-side switch 542 are connected in series sequentially from the P busbar 502 to the N busbar 501.

[0036] The U-phase busbar 503 is connected to the output terminal 540b of the U-phase switch module 531. The V-phase busbar 504 is connected to the output terminal 540b of the V-phase switch module 532. The W-phase busbar 505 is connected to the output terminal 540b of the W-phase switch module 533.

[0037] Motor 400 has a U-phase stator coil, a V-phase stator coil, and a W-phase stator coil. A U-phase busbar 503 is electrically connected to the U-phase stator coil. A V-phase busbar 504 is electrically connected to the V-phase stator coil. A W-phase busbar 505 is electrically connected to the W-phase stator coil. This electrically connects the inverter 510 and the motor 400.

[0038] The gate terminals 540d of the high-side switch 541 and low-side switch 542 included in the U-phase switch modules 531 to W-phase switch modules 533 are connected to the gate driver.

[0039] The gate driver, along with some of the ECUs mentioned above, is included in the circuit board 550 shown in Figure 1. The ECU generates a control signal and outputs it to the gate driver. The gate driver amplifies the control signal and outputs it to the gate terminal 540d. As a result, the high-side switch 541 and the low-side switch 542 are opened and closed by the ECU. Note that the board on which the gate driver is mounted and the board on which the ECU is mounted may be separate.

[0040] The ECU generates pulse signals as control signals. The ECU adjusts the duty cycle and frequency of these pulse signals. These duty cycle and frequency are determined based on the outputs of various sensors, etc.

[0041] When motor 400 is operating, the high-side switch 541 and low-side switch 542 of the three-phase switch module are PWM controlled by the output of a control signal from the ECU. This generates a three-phase alternating current in the power conversion circuit 500. This three-phase alternating current is input to the three phase stator coils. This generates a three-phase rotating magnetic field in the three phase stator coils. The interaction between this three-phase rotating magnetic field and the magnetic field generated from the rotor of motor 400 generates rotational torque in the rotor.

[0042] When the motor 400 generates electricity (regenerates) due to the rotational energy of the driving wheels, the ECU, for example, stops outputting the control signal. As a result, the AC power generated by the regeneration passes through the diodes of the three-phase switch module. Consequently, the AC power is converted to DC power.

[0043] Furthermore, the type of switch element provided in the U-phase switch modules 531 to W-phase switch modules 533 is not particularly limited; for example, MOSFETs can be used. The semiconductor elements such as switches and diodes included in these three-phase switch modules can be manufactured from semiconductors such as Si and wide-bandgap semiconductors such as SiC. The constituent materials of the semiconductor elements are not particularly limited.

[0044] Furthermore, the number of high-side switches 541 and low-side switches 542 in a three-phase switch module is not limited to one. At least one of the three-phase switch modules may have multiple high-side switches 541 and multiple low-side switches 542 connected in parallel. The number of switches connected in parallel can be determined based on the rated current of the switches and the amount of current that can be energized by the power conversion circuit 500.

[0045] <Case> Case 600 is made of a high-permeability material with higher magnetic permeability than air. Specifically, case 600 is made of a metallic material such as alumina or iron. The capacitor case 521 and the switch case 543 are housed in case 600. The components of the power conversion circuit 500 shown in Figure 1 are housed in case 600. In addition, current sensors and other components not shown are also housed in case 600.

[0046] As schematically shown in Figures 2 to 4, case 600 has three main components: a first case 610, a second case 620, and a third case 630. The first case 610 and the third case 630 are aligned in the Z direction via the second case 620. The first case 610 and the second case 620 are connected via a seal, and the second case 620 and the third case 630 are connected via a seal. This forms a refrigerant passage 700 inside case 600. The refrigerant passage 700 is mainly partitioned by the walls of the first case 610, the second case 620, and the third case 630. Note that the condenser case 521 and the switch case 543 are not shown in Figure 2 because they would obscure case 600, but they are shown in Figures 3 and 4.

[0047] The first case 610 has a first upper surface 610a and a first lower surface 610b aligned in the Z direction. The second case 620 has a second upper surface 620a and a second lower surface 620b aligned in the Z direction. The third case 630 has a third upper surface 630a and a third lower surface 630b aligned in the Z direction.

[0048] The first case 610 and the second case 620 are connected in such a manner that the first upper surface 610a and the second lower surface 620b face each other in the Z direction. The second case 620 and the third case 630 are connected in such a manner that the second upper surface 620a and the third lower surface 630b face each other in the Z direction.

[0049] As shown in Figures 3 and 4, the first upper surface 610a and the second lower surface 620b are partially undulating in the Z direction. The third lower surface 630b follows a plane perpendicular to the Z direction, while the second upper surface 620a is partially undulating in the Z direction. The partial contact between the first upper surface 610a and the second lower surface 620b constitutes a portion of the refrigerant passage 700. Similarly, the partial contact between the second upper surface 620a and the third lower surface 630b also constitutes a portion of the refrigerant passage 700.

[0050] Furthermore, the second case 620 has a through-hole that penetrates the second upper surface 620a and the second lower surface 620b. This through-hole also constitutes part of the refrigerant passage 700. This through-hole connects the space formed by the first upper surface 610a and the second lower surface 620b with the space formed by the second upper surface 620a and the third lower surface 630b.

[0051] As shown in Figure 2, an input pipe 701 and a discharge pipe 702 are connected to the refrigerant passage 700. These input pipe 701 and discharge pipe 702 are connected to a pump (not shown). The refrigerant flowing into the refrigerant passage 700 from the input pipe 701 exchanges heat with the components of the power conversion circuit 500 housed in case 600. This heat-exchanged refrigerant is returned to the pump via the discharge pipe 702. The temperature of the refrigerant returned to the pump is lowered by a cooling device such as a radiator. This lowered temperature refrigerant is then supplied back to the input pipe 701. The input pipe 701 is constructed from the second case 620, and the discharge pipe 702 is constructed from the first case 610. However, these input pipe 701 and discharge pipe 702 may be constructed separately from case 600.

[0052] <Refrigerant passage> The refrigerant passage 700 includes a first refrigerant passage 710, a second refrigerant passage 720, and a third refrigerant passage 730. The refrigerant passage 700 also includes a first connecting hole 751 and a second connecting hole 752.

[0053] The first refrigerant passage 710 and the second refrigerant passage 720 are composed of a first upper surface 610a and a second lower surface 620b. The first communication hole 751 is also composed of a first upper surface 610a and a second lower surface 620b.

[0054] The third refrigerant passage 730 is composed of a second upper surface 620a and a third lower surface 630b. The second communication hole 752 is a through hole in the second case 620 that penetrates the second upper surface 620a and the second lower surface 620b.

[0055] An input pipe 701 is connected to the first refrigerant passage 710. The first refrigerant passage 710 and the second refrigerant passage 720 are connected via a first communication hole 751. The second refrigerant passage 720 and the third refrigerant passage 730 are connected via a second communication hole 752. An outlet pipe 702 is connected to the third refrigerant passage 730.

[0056] Due to this mechanical configuration, the refrigerant supplied to the input pipe 701 passes through the first refrigerant passage 710, the first communication hole 751, the second refrigerant passage 720, the second communication hole 752, and the third refrigerant passage 730 in that order before being discharged to the discharge pipe 702.

[0057] The first refrigerant passage 710 is located on the upstream side in the direction of refrigerant flow, and the third refrigerant passage 730 is located on the downstream side. As the refrigerant travels from upstream to downstream, it exchanges heat with various components of the power conversion circuit 500 housed in the case 600. Therefore, the temperature of the refrigerant is higher downstream than upstream.

[0058] As shown in Figure 3, a condenser case 521 is provided on the second upper surface 620a of the second case 620. In the Z direction, the first refrigerant passage 710 and the condenser case 521 are aligned. The condenser case 521 is pressed against the second case 620 by bolts or the like. This allows for active heat conduction between the condenser case 521 and the second case 620. The temperature rise of the smoothing condenser 520 housed in the condenser case 521 is suppressed mainly by the refrigerant passing through the first refrigerant passage 710. The condenser case 521 corresponds to the first component. The first refrigerant passage 710 corresponds to the first cooling channel.

[0059] The refrigerant that has exchanged heat with the smoothing condenser 520 flows from the first refrigerant passage 710 to the second refrigerant passage 720. This refrigerant then flows from the second refrigerant passage 720 to the third refrigerant passage 730. In this way, the second refrigerant passage 720 functions as a relay between the first refrigerant passage 710 and the third refrigerant passage 730. The second refrigerant passage 720 corresponds to a connecting passage.

[0060] As shown in Figures 3 and 4, a switch case 543 is provided on the third upper surface 630a of the third case 630. In the Z direction, the third refrigerant passage 730 and the switch case 543 are aligned. The switch case 543 is pressed against the third case 630 by a fixing member (not shown). This allows the switch case 543 and the third case 630 to actively conduct heat. The temperature rise of the switch group 530 housed in the switch case 543 is suppressed mainly by the refrigerant passing through the third refrigerant passage 730. The switch case 543 corresponds to the second component. The third refrigerant passage 730 corresponds to the second cooling channel.

[0061] The refrigerant that has exchanged heat with the switch group 530 is returned to the pump via the discharge pipe 702. The temperature of this refrigerant is lowered by the cooling device and supplied again to the first refrigerant passage 710.

[0062] <Fluid flow velocity> As the refrigerant passes through the refrigerant passage 700, its flow direction changes according to the shape of the passage 700. This causes pressure loss and a decrease in the refrigerant's flow velocity. As a result, there is a concern that the cooling effect of the refrigerant-based power conversion circuit 500 will decrease.

[0063] <Refrigerant passage> To solve these problems, the shape of the refrigerant passage 700 has been modified in this disclosure. The refrigerant passage 700 will be described in detail below.

[0064] As shown in Figure 5, in the Y direction, the input pipe 701, the first refrigerant passage 710, the second refrigerant passage 720, the third refrigerant passage 730, and the discharge pipe 702 are arranged in that order.

[0065] In the Z direction, the first refrigerant passage 710 is located below the second refrigerant passage 720 and the third refrigerant passage 730. The second refrigerant passage 720 is located between the first refrigerant passage 710 and the third refrigerant passage 730 in the Z direction. The third refrigerant passage 730 is located above the first refrigerant passage 710 and the second refrigerant passage 720 in the Z direction.

[0066] The first refrigerant passage 710 and the second refrigerant passage 720 are not aligned in the Z direction, but are aligned in the Y direction. The second refrigerant passage 720 and the third refrigerant passage 730 are aligned in both the Z and Y directions.

[0067] The refrigerant flows through the refrigerant passage 700, but since the refrigerant is a fluid, its direction of flow is not uniquely determined. However, for the sake of simplicity, in this disclosure, the direction in which the refrigerant is primarily expected to flow will be referred to as the direction of refrigerant flow. The refrigerant flows from the input pipe 701 to the discharge pipe 702. When the refrigerant passage 700 is filled with refrigerant, the refrigerant flowing through the passage 700 is expected to flow primarily along the direction of extension of the wall surface that partitions the refrigerant passage 700. This direction of refrigerant flow is, of course, the same for the input pipe 701 and the discharge pipe 702.

[0068] The input pipe 701 extends in the Y direction. Therefore, the flow direction of the refrigerant flowing into this input pipe 701 is in the Y direction. This refrigerant flowing in the Y direction flows into the first refrigerant passage 710.

[0069] The first refrigerant passage 710 extends in the Y direction. The first refrigerant passage 710 is short in the Z direction but wide in the X direction. The width of the first refrigerant passage 710 in the X direction gradually widens from the input pipe 701 toward the first communication hole 751, becomes constant, and then gradually narrows. Thus, the shape of the first refrigerant passage 710 changes from the input pipe 701 toward the first communication hole 751. However, the flow path cross-sectional area of ​​the first refrigerant passage remains constant.

[0070] The refrigerant flowing through the first refrigerant passage 710 flows mainly in the Y direction. At the same time, as the refrigerant flowing through the first refrigerant passage 710 moves from the input pipe 701 towards the first communication hole 751, it flows away from the input pipe 701 in the X direction, and after becoming constant, it flows gradually towards the first communication hole 751 in the X direction.

[0071] The refrigerant, with its flow direction in the Y and X directions, flows into the second refrigerant passage 720 through the first communication hole 751. The shape of the first communication hole 751 is equivalent to the shape of the first refrigerant passage 710 on the second refrigerant passage 720 side.

[0072] As shown in Figures 3 and 5, the length of the first communication hole 751 in the Y direction is shorter than its lengths in the X and Z directions. The first communication hole 751 opens into the wall surface that partitions the first refrigerant passage 710 and the wall surface that partitions the second refrigerant passage 720, but the shapes of these two openings are identical. In this embodiment, the positions of these two openings in the X and Z directions are identical.

[0073] Due to this configuration, the flow direction of the refrigerant flowing through the first connecting hole 751 is not easily corrected by the wall surface constituting the first connecting hole 751. The refrigerant flowing in the Y and X directions as described above flows into the second refrigerant passage 720. The first connecting hole 751 corresponds to the inlet.

[0074] The second refrigerant passage 720 extends in both the Y and Z directions. The flow path cross-sectional area of ​​the second refrigerant passage 720 gradually narrows in the Y direction as it moves away from the first refrigerant passage 710. The width of the second refrigerant passage 720 in the X direction gradually narrows as it moves from the first refrigerant passage 710 towards the third refrigerant passage 730.

[0075] Due to this shape, the refrigerant flowing through the second refrigerant passage 720 flows in the Y, Z, and X directions. The refrigerant flowing through the second refrigerant passage 720 flows in the Y direction, counteracting gravity. At the same time, as the refrigerant flowing through the second refrigerant passage 720 moves from the first communication hole 751 to the second communication hole 752 in the Y and Z directions, it gradually approaches the second communication hole 752 in the X direction.

[0076] The refrigerant, with its flow direction in the Y, Z, and X directions, flows into the second communication hole 752. The second communication hole 752 extends in the Z direction. The second communication hole 752 is aligned with the switch case 543 in the Z direction. The second communication hole 752 opens into the wall that partitions the second refrigerant passage 720 and the wall that partitions the third refrigerant passage 730, but the shapes of these two openings are identical. The positions of these two openings in the X and Y directions are identical. Therefore, the flow direction of the refrigerant flowing from the second refrigerant passage 720 into the second communication hole 752 is changed from the Y, Z, and X directions to mainly the Z direction. This refrigerant with its flow direction in the Z direction flows up into the third refrigerant passage 730. The second communication hole 752 corresponds to the outlet.

[0077] Furthermore, the Y-direction positions of the openings in the wall that partition the second refrigerant passage 720 and the openings in the wall that partition the third refrigerant passage 730 in the second communication hole 752 do not have to be the same. The opening in the wall that partitions the second refrigerant passage 720 in the second communication hole 752 may be located closer to the first refrigerant passage 710 in the Y-direction than the opening in the wall that partitions the third refrigerant passage 730. The wall connecting these two openings may also be inclined with respect to the Z-direction. In this configuration, the flow direction of the refrigerant flowing from the second refrigerant passage 720 into the second communication hole 752 is changed from the Y-direction, Z-direction, and X-direction to mainly the Y-direction and Z-direction. This refrigerant with the Y-direction and Z-direction as its flow direction flows up into the third refrigerant passage 730.

[0078] The third refrigerant passage 730 extends in the Y direction. The flow path cross-sectional area of ​​the third refrigerant passage 730 is constant. The third refrigerant passage 730 is short in the Z direction but wide in the X direction. The width of the third refrigerant passage 730 in the X direction is constant. The openings of the second communication hole 752 and the third communication hole 753 in the third refrigerant passage 730 are spaced apart in the Y direction, but are at the same position in the X direction. Therefore, the refrigerant flowing through the third refrigerant passage 730 flows mainly in the Y direction. This refrigerant flowing in the Y direction through the third refrigerant passage 730 flows into the discharge pipe 702. The refrigerant that flows into the discharge pipe 702 is returned to the pump described above.

[0079] <Second refrigerant passage> As described above, the first refrigerant passage 710 and the third refrigerant passage 730 are separated in both the Y and Z directions. This separation in the Z direction is because the smoothing condenser 520 is larger than the switch group 530. This is to efficiently cool both while minimizing the increase in the size of the case 600. Due to these circumstances, the first refrigerant passage 710 and the third refrigerant passage 730 are separated in the Z direction, and the second refrigerant passage 720, which connects them, extends in the Z direction. It is desirable to devise a way to suppress the decrease in the flow velocity of the refrigerant flowing through the second refrigerant passage 720 against gravity.

[0080] As described above, the second refrigerant passage 720 is composed of the first upper surface 610a of the first case 610 and the second lower surface 620b of the second case 620. In the following description, in order to simplify the explanation of the second refrigerant passage 720, the wall surface that partitions this second refrigerant passage 720 will be divided into six surfaces. That is, the wall surface that partitions the second refrigerant passage 720 will be divided into a second left surface 721 and a second right surface 722 spaced apart in the X direction, a second front surface 723 and a second rear surface 724 spaced apart in the Y direction, and a second top surface 725 and a second bottom surface 726 spaced apart in the Z direction.

[0081] The second left surface 721 is located closer to the input pipe 701 in the X direction than the second right surface 722. The second front surface 723 is located closer to the first refrigerant passage 710 in the Y direction than the second rear surface 724. The second top surface 725 is located above the second bottom surface 726 in the Z direction.

[0082] The second annular surface 727 is formed by sequentially connecting the second left surface 721, the second rear surface 724, the second right surface 722, and the second front surface 723. The opening located on the upper side in the Z direction of this second annular surface 727 is closed by the second top surface 725, and the opening located on the lower side in the Z direction is closed by the second bottom surface 726. The second top surface 725, the second bottom surface 726, and the second annular surface 727 correspond to the connecting surfaces.

[0083] A first communication hole 751 is open on the second bottom surface 726 side of the second front surface 723. A second communication hole 752 is open on the second top surface 725.

[0084] As shown in Figures 3 and 4, the second bottom surface 726 is partially raised toward the second top surface 725. Further detailing this partially raised area, the second bottom surface 726 has a first side surface 726a and a second side surface 726b spaced apart in the X direction, and a sloped surface 726c and a back surface 726d spaced apart in the Y direction. The raised area of ​​the second bottom surface 726 also has a bottom top surface 726e located above these four surfaces in the Z direction. The first side surface 726a, the back surface 726d, the second side surface 726b, and the sloped surface 726c are connected in sequence to form a ring. Of the two openings formed by these four ring-shaped surfaces, the opening located higher in the Z direction is closed by the bottom top surface 726e. The five surfaces forming the partially raised portion of this second bottom surface 726 are spaced apart from and facing the other five surfaces other than the second bottom surface 726 that partition the second refrigerant passage 720.

[0085] Specifically, the first side surface 726a faces the second left surface 721 while being spaced apart in the X direction. The second side surface 726b faces the second right surface 722 while being spaced apart in the X direction. The inclined surface 726c faces the second front surface 723 while being spaced apart in the Y direction. The back surface 726d faces the second rear surface 724 while being spaced apart in the Y direction. The bottom top surface 726e faces the second top surface 725 while being spaced apart in the Z direction. Furthermore, between the bottom top surface 726e and the second top surface 725, the second left surface 721 and the second right surface 722 face each other while being spaced apart, and the second front surface 723 and the second rear surface 724 face each other while being spaced apart. These spaced-apart surfaces form a space through which the refrigerant flows.

[0086] As shown in Figure 4, the second left surface 721 and the second right surface 722 extend in the Z direction. However, the second right surface 722 is more inclined with respect to the Z direction than the second left surface 721. The distance between the second left surface 721 and the second right surface 722 in the X direction gradually decreases in the Z direction as you move from the second bottom surface 726 towards the second top surface 725.

[0087] Due to this configuration, as shown in Figure 5, the width of the second refrigerant passage 720 in the X direction gradually narrows as it moves from the first communication hole 751 to the second communication hole 752.

[0088] As shown in Figure 3, the second front surface 723 and the second rear surface 724 extend in the Z direction. However, the second front surface 723 is more inclined with respect to the Z direction than the second rear surface 724. The distance between the second front surface 723 and the second rear surface 724 in the Y direction gradually decreases in the Z direction as you move from the second bottom surface 726 towards the second top surface 725.

[0089] The slope 726c of the partially raised portion of the second base surface 726 and the back surface 726d extend in the Z direction. However, the slope 726c is more steeply inclined in the Z direction than the back surface 726d. The inclination angle of the slope 726c is uniform.

[0090] The distance between the inclined surface 726c and the back surface 726d in the Y direction gradually decreases in the Z direction as you move from the second bottom surface 726 towards the second top surface 725. In other words, the inclined surface 726c is tilted such that as you move from the first communication hole 751 towards the second communication hole 752 in the Y direction, the distance between it and the second communication hole 752 in the Z direction gradually decreases.

[0091] Due to this configuration, the inclined space 720a, which is located between the slope 726c and the second front surface 723 in the second refrigerant passage 720 and between the second left surface 721 and the second right surface 722, as shown by the dashed line in Figure 3, extends in the Y direction and is inclined with respect to the Z direction. The width of the inclined space 720a in the X direction gradually narrows from the first communication hole 751 toward the second communication hole 752.

[0092] As shown in Figure 3, the first communication hole 751 and the inclined surface 726c are opposite each other in the Y direction. Therefore, the refrigerant flowing into the second refrigerant passage 720 from the first communication hole 751 first flows through the inclined space 720a. The refrigerant that flows up the inclined surface 726c flows into the upper space 720b, which is located between the bottom upper surface 726e and the second top surface 725 in the Z direction, as indicated by the dashed line in Figure 3. This upper space 720b is aligned with the second communication hole 752 in the Z direction. Furthermore, this upper space 720b is in communication with the rear space 720c, which is located between the back surface 726d and the second rear surface 724 in the Y direction, as indicated by the dashed line in Figure 3. Therefore, some of the refrigerant that flows into the upper space 720b also flows into this rear space 720c.

[0093] The refrigerant that flows up from the inclined space 720a to the upper space 720b flows into the second communication hole 752 which is open in the second top surface 725. The refrigerant that flows from the upper space 720b to the rear space 720c changes direction at the wall surface that makes up the rear space 720c and flows back into the upper space 720b. The refrigerant from both the inclined space 720a and the rear space 720c flows into the upper space 720b and flows up into the third refrigerant passage 730 via the second communication hole 752.

[0094] Furthermore, lateral spaces are formed between the second left surface 721 and the first side surface 726a, and between the second right surface 722 and the second side surface 726b. The inclined space 720a and the rear space 720c are connected through these lateral spaces. A portion of the refrigerant that flows into the inclined space 720a from the first communication hole 751 flows to the upper space 720b through these lateral spaces.

[0095] Furthermore, although not strictly necessary and shown only in Figure 5, a flow straightening plate 728 may be provided on the slope 726c to adjust the direction of refrigerant flow. The flow straightening plate 728 extends in the direction connecting the first communication hole 751 and the second communication hole 752. The flow straightening plate 728 corresponds to the flow straightening section.

[0096] <Second communication hole> As shown in Figures 3 and 4, the second communication hole 752 extends in the Z direction. The second communication hole 752 opens into the second top surface 725 and into the region of the second upper surface 620a that partitions the third refrigerant passage 730. The two openings of the second communication hole 752 are similar in shape.

[0097] As shown in Figures 6 and 6, the opening shape of the second communication hole 752 is divided into a left edge portion 752a and a right edge portion 752b that are spaced apart in the X direction, and a front edge portion 752c and a rear edge portion 752d that are spaced apart in the Y direction.

[0098] The left edge 752a corresponds to the first edge. The right edge 752b corresponds to the second edge. The leading edge 752c corresponds to the third edge. The trailing edge 752d corresponds to the fourth edge.

[0099] The left edge 752a is located closer to the input pipe 701 in the X direction than the right edge 752b. The leading edge 752c is located closer to the first refrigerant passage 710 in the Y direction than the trailing edge 752d. The left edge 752a, trailing edge 752d, right edge 752b, and leading edge 752c are connected in sequence to form the opening of the annular second communication hole 752. The opening of the second communication hole 752 is longer in the Y direction than in the X direction.

[0100] The leading edge 752c and trailing edge 752d extend in the X direction. The trailing edge 752d is shorter in the X direction than the leading edge 752c.

[0101] The left edge 752a extends in the Y direction. The right edge 752b extends in a direction inclined with respect to the Y direction. The right edge 752b is inclined such that the distance between it and the left edge 752a in the X direction gradually decreases as it moves from the leading edge 752c to the trailing edge 752d in the Y direction.

[0102] Due to the opening shape, the third refrigerant passage 730 extends in the Y direction. Therefore, the refrigerant flows up in the Z direction through the second communication hole 752 and flows out into the third refrigerant passage 730, as shown by the solid arrows in Figure 6, flowing more in the Y direction than in the X direction. The refrigerant that flows up into the third refrigerant passage 730 flows towards the discharge pipe 702, which is spaced apart from the second communication hole 752 in the Y direction.

[0103] Furthermore, the opening shape on the second upper surface 620a of the second communication hole 752 may be trapezoidal or triangular, as previously described. Also, the right edge portion 752b may extend in the Y direction. At the same time, the left edge portion 752a may be inclined such that the distance between it and the right edge portion 752b in the X direction gradually decreases as it moves from the front edge portion 752c to the rear edge portion 752d in the Y direction. At least one of the left edge portion 752a and the right edge portion 752b may be inclined such that the distance between it and the other of the left edge portion 752a and the right edge portion 752b in the X direction gradually decreases as it moves from the front edge portion 752c to the rear edge portion 752d in the Y direction.

[0104] <Third refrigerant passage> As described above, the third refrigerant passage 730 is composed of the second upper surface 620a of the second case 620 and the third lower surface 630b of the third case 630. In the following description, in order to simplify the explanation of the third refrigerant passage 730, the wall surface that partitions this third refrigerant passage 730 will be divided into six surfaces. Specifically, the wall surface that partitions the third refrigerant passage 730 will be divided into the third left surface 731 and the third right surface 732, which are spaced apart in the X direction; the third front surface 733 and the third rear surface 734, which are spaced apart in the Y direction; and the third top surface 735 and the third bottom surface 736, which are spaced apart in the Z direction.

[0105] The third left surface 731 is located closer to the input pipe 701 in the X direction than the third right surface 732. The third front surface 733 is located closer to the first refrigerant passage 710 in the Y direction than the third rear surface 734. The third top surface 735 is located above the third bottom surface 736 in the Z direction.

[0106] The third annular surface 737 is formed by sequentially connecting the third left surface 731, the third rear surface 734, the third right surface 732, and the third front surface 733. The opening located on the upper side in the Z direction of this third annular surface 737 is closed by the third top surface 735, and the opening located on the lower side in the Z direction is closed by the third bottom surface 736.

[0107] A second communication hole 752 is opened on the third left surface 731 side of the third bottom surface 736. A third communication hole 753 is opened on the third right surface 732. The openings of the second communication hole 752 and the third communication hole 753 are aligned while being spaced apart in the Y direction.

[0108] <Heat dissipation fins> As shown in Figures 3 and 4, multiple heat dissipation fins 738 are formed on the third top surface 735. In Figure 7, these multiple heat dissipation fins 738 are shown with dashed lines. The multiple heat dissipation fins 738 are spaced apart in a direction perpendicular to the Z direction. Some of the multiple heat dissipation fins 738 are aligned with the second communication hole 752 in the Z direction.

[0109] <Effects and Effects> A first refrigerant passage 710 and a third refrigerant passage 730, both extending in the Y direction, are spaced apart in the Y and Z directions. A second refrigerant passage 720, which connects the first and third refrigerant passages 710 and 730, extends in both the Y and Z directions. The inclined surface 726c of the wall partitioning the second refrigerant passage 720 gradually changes its distance from the second communication hole 752 in the Z direction as it approaches the second communication hole 752 from the first communication hole 751 in the Y direction. Furthermore, the opening shape of the second communication hole 752, which connects the second refrigerant passage 720 and the third refrigerant passage 730, is longer in the Y direction than in the X direction.

[0110] According to this, the flow direction of the refrigerant flowing in the Y direction through the first refrigerant passage 710 is converted to the Z and Y directions in the second refrigerant passage 720, and the refrigerant can then flow into the third refrigerant passage 730 which extends in the Y direction. Due to the shape of the inclined surface 726c, the decrease in the flow velocity of the refrigerant due to collision is suppressed. Due to the shape of the second connecting hole 752, it is easier to flow the refrigerant into the third refrigerant passage 730 which extends in the Y direction. As a result, the decrease in the flow velocity of the refrigerant is suppressed.

[0111] The slope 726c is inclined such that, as it approaches the second communication hole 752 from the first communication hole 751 in the Y direction, the distance between it and the second communication hole 752 in the Z direction gradually decreases. The slope 726c is aligned with the first communication hole 751 in the Y direction.

[0112] According to this, the decrease in refrigerant flow velocity due to collision with slope 726c is suppressed.

[0113] The opening shape of the second communication hole 752 is divided by a left edge portion 752a and a right edge portion 752b that are separated in the X direction, and a rear edge portion 752d and a front edge portion 752c that are separated in the Y direction. The right edge portion 752b is inclined such that the distance between it and the left edge portion 752a in the X direction gradually increases as it moves from the rear edge portion 752d toward the front edge portion 752c in the Y direction.

[0114] Therefore, the refrigerant that flows up from the second communication hole 752 into the third refrigerant passage 730 is more likely to flow in the Y direction, which is the extension of the third refrigerant passage 730, than in the X direction. This refrigerant then flows more easily toward the third communication hole 753 in the third refrigerant passage 730.

[0115] The cross-sectional area of ​​the flow path on the inclined space 720a side of the second refrigerant passage 720 is narrower on the second communication hole 752 side than on the first communication hole 751 side. This suppresses the decrease in the flow velocity of the refrigerant flowing up the inclined space 720a against gravity.

[0116] In the second refrigerant passage 720, the inclined space 720a and the rear space 720c are aligned in the Y direction via the inclined surface 726c. The second rear surface 724 side of the upper space 720b, which communicates with the rear space 720c, is aligned with the second communication hole 752 in the Z direction. This second communication hole 752 is aligned with the switch case 543 in the Z direction.

[0117] According to this, the switch case 543 is more easily cooled by the refrigerant on the second rear surface 724 side of the rear space 720c and the upper space 720b.

[0118] Some of the multiple heat dissipation fins 738 are aligned with the second communication hole 752 in the Z direction. This makes it easier to suppress the temperature rise of the third case 630 on which the heat dissipation fins 738 are provided. As a result, it is easier to suppress the temperature rise of the switch case 543 provided in the third case 630.

[0119] <Second Embodiment> This embodiment will be described primarily in terms of its differences from the first embodiment. In subsequent embodiments, the differences from the previously described embodiment will also be described primarily in terms of their differences. Configurations, operations, and effects not specifically described in other embodiments are the same as those described in the previously described embodiment.

[0120] The ease with which the refrigerant flows in the second refrigerant passage 720 is determined primarily by the first connecting hole 751, the inclined space 720a, the upper space 720b, and the second connecting hole 752. The flow region 720R that determines the ease with which the refrigerant flows in this second refrigerant passage 720 can be designed based on the design region DA shown by the dashed line in Figure 8.

[0121] As shown in Figure 9, the design domain DA is a triangular pyramid. The design domain DA has a first vertex A, a second vertex B, a third vertex C, and a fourth vertex D. The design domain DA has a first line segment AB connecting the first vertex A and the second vertex B, a second line segment AC connecting the first vertex A and the third vertex C, and a third line segment AD connecting the first vertex A and the fourth vertex D. The design domain DA has a fourth line segment BC connecting the second vertex B and the third vertex C, a fifth line segment CD connecting the third vertex C and the fourth vertex D, and a sixth line segment DB connecting the fourth vertex D and the second vertex B.

[0122] The first vertex A is located above the second vertex B, the third vertex C, and the fourth vertex D in the Z direction. The second vertex B is located below the first vertex A, the third vertex C, and the fourth vertex D in the Z direction. The positions of the third vertex C and the fourth vertex D are equal in the Z direction. The positions of the third vertex C and the fourth vertex D in the Z direction are between the first vertex A and the second vertex B.

[0123] As shown above, the design region DA has four vertices and six line segments. At least a portion of these four vertices and six line segments are included in the form of the flow region 720R.

[0124] As shown in Figure 10, the form of the flow region 720R is determined by a portion of the design region DA. The first vertex A of the design region DA forms the second communication hole 752 side of the second refrigerant passage 720. The second vertex B forms the second bottom surface 726 side of the second refrigerant passage 720. The third vertex C and the fourth vertex D form the first communication hole 751 side of the second refrigerant passage 720.

[0125] The flow region 720R is designed by dividing a portion of the design region DA. Specifically, the region containing the first vertex A of the design region DA is divided by a plane intersecting in the Z direction. In this embodiment, the region containing the second vertex B of the design region DA is also divided by a plane intersecting in the Z direction. The region containing the third vertex C and the fourth vertex D of the design region DA is divided by a plane intersecting in the Y direction. In this way, the form of the flow region 720R is designed.

[0126] The flow region 720R shown in Figure 10 has vertices 11ABA, 12ABB, 13ACA, 14ACC, 15ADA, 16ADD, 17BCC, and 18BDD.

[0127] The 11th vertex ABA and the 12th vertex ABB are included in the first segment AB. The 13th vertex ACA and the 14th vertex ACC are included in the second segment AC. The 15th vertex ADA and the 16th vertex ADD are included in the third segment AD. The 17th vertex BCC is included in the fourth segment BC. The 18th vertex BDD is included in the sixth segment DB.

[0128] The positions of the 11th vertex ABA, the 13th vertex ACA, and the 15th vertex ADA in the Z direction are equivalent. Connecting these three points in order forms a triangle. This triangle represents the second communication hole 752 included in the flow region 720R.

[0129] The positions of the 14th vertex ACC, the 16th vertex ADD, the 18th vertex BDD, and the 17th vertex BCC are equivalent in the Y direction. Connecting these four points in order forms a quadrilateral. This quadrilateral represents the first communication hole 751 contained within the flow region 720R.

[0130] The positions of the 13th vertex ACA and the 15th vertex ADA are equivalent in the Y direction. The positions of the 14th vertex ACC and the 16th vertex ADD are equivalent in the Y direction. A quadrilateral is formed by connecting the 13th vertex ACA, the 15th vertex ADA, the 16th vertex ADD, and the 14th vertex ACC in order. This quadrilateral represents at least a part of the second front surface 723. In this flow region 720R, the triangle representing the second communication hole 752 and the quadrilateral representing the first communication hole 751 are connected via the quadrilateral representing the second front surface 723.

[0131] A pentagon is formed by connecting the 11th vertex ABA, the 13th vertex ACA, the 14th vertex ACC, the 17th vertex BCC, and the 12th vertex ABB in that order. This pentagon represents at least a portion of the second left face 721.

[0132] A pentagon is formed by connecting the 11th vertex ABA, the 15th vertex ADA, the 16th vertex ADD, the 18th vertex BDD, and the 12th vertex ABB in that order. This pentagon represents at least a portion of the second right face 722.

[0133] A triangle is formed by connecting the 12th vertex ABB, the 17th vertex BCC, and the 18th vertex BDD in order. This triangle represents at least a portion of the second base 726. This triangle also represents the slope 726c.

[0134] As described above, the second front surface 723, second left surface 721, second right surface 722, and inclined surface 726c, represented in the flow region 720R, represent the regions that primarily determine the ease of refrigerant flow in the inclined space 720a and the upper space 720b.

[0135] <Third Embodiment> In this embodiment, compared to the configuration of the second embodiment, the position of the 12th vertex ABB in the Z direction is on the side of the 11th vertex ABA. Therefore, as shown in Figure 11, the inclination with respect to the Z direction of the triangle formed by sequentially connecting the 12th vertex ABB, the 17th vertex BCC, and the 18th vertex BDD, which represent the slope 726c in the flow region 720R, is larger.

[0136] In this embodiment, the length between the 11th vertex ABA and the 12th vertex ABB is shorter than the length between the 13th vertex ACC and the 17th vertex BCC. This indicates that the shortest distance between the inclined surface 726c and the second communication hole 752 in the Z direction is shorter than the length of the first communication hole 751 in the Z direction. As a result, collisions between the refrigerant flowing along the inclined surface 726c to the second communication hole 752 and the wall surface constituting the rear space 720c, and the refrigerant in the rear space 720c are suppressed. This suppresses the decrease in the flow velocity of the refrigerant due to such collisions. Consequently, the decrease in the flow velocity of the refrigerant flowing out from the second communication hole 752 to the third refrigerant passage 730 is suppressed.

[0137] <Fourth Embodiment> In this embodiment, the 12th vertex ABB is absent. In other words, the 12th vertex ABB overlaps with the 11th vertex ABA. Therefore, in this embodiment, as shown in Figure 12, the slope 726c is represented by a triangle formed by connecting the 11th vertex ABA, the 17th vertex BCC, and the 18th vertex BDD in order. In this configuration, the inclination of the slope 726c with respect to the Z direction is maximized.

[0138] <Fifth Embodiment> In this embodiment, as shown in Figure 13, the 14th vertex ACC and the 16th vertex ADD are located closer to the 1st vertex A than the 17th vertex BCC and the 18th vertex BDD. The 17th vertex BCC is equal to the 3rd vertex C, and the 18th vertex BDD is equal to the 4th vertex D.

[0139] Therefore, in the flow region 720R, the quadrilateral formed by sequentially connecting the 14th vertex ACC, the 16th vertex ADD, the 18th vertex BDD, and the 17th vertex BCC, which represent the first communication hole 751, is inclined with respect to the Z direction.

[0140] <Sixth Embodiment> In this embodiment, as shown in Figure 14, the second base surface 726 is composed of two faces. One of these faces is a triangle formed by connecting the 12th vertex ABB, the 19th vertex BCB, and the 20th vertex BDB in order. The other face is a quadrilateral formed by connecting the 19th vertex BCB, the 20th vertex BDB, the 18th vertex BDD, and the 17th vertex BCC.

[0141] The triangle shown above is inclined with respect to the Z direction and forms part of the slope 726c. The quadrilateral shown above forms part of the triangle formed by connecting the second vertex B, the third vertex C, and the fourth vertex D of the design region DA. This quadrilateral represents the side of the first communication hole 751 of the second base surface 726.

[0142] The triangle representing the inclined surface 726c is inclined such that the distance between it and the second communication hole 752 in the Z direction decreases as you move from the first communication hole 751 towards the second communication hole 752. Conversely, the quadrilateral representing the first communication hole 751 side of the second base surface 726 is inclined such that the distance between it and the second communication hole 752 in the Z direction increases as you move from the first communication hole 751 towards the second communication hole 752.

[0143] <Seventh Embodiment> As shown in Figure 15, the flow region 720R of this embodiment has the characteristics of the flow region 720R of the fifth and sixth embodiments. Specifically, in the flow region 720R, the rectangle formed by sequentially connecting the 14th vertex ACC, the 16th vertex ADD, the 18th vertex BDD, and the 17th vertex BCC, which represent the first communication hole 751, is inclined with respect to the Z direction. Furthermore, the second base surface 726 is composed of two surfaces.

[0144] However, the 19th vertex BCB and the 20th vertex BDB are located closer to the 3rd vertex C and the 4th vertex D than to the 2nd vertex B. Therefore, the triangle representing the slope 726c has a larger area than the quadrilateral representing the 1st communication hole 751 side of the 2nd base 726.

[0145] <Eighth Embodiment> As shown in Figure 16, this embodiment differs from the seventh embodiment in that the positions of the 14th vertex ACC and the 16th vertex ADD are different. The position of the 14th vertex ACC is off the second line segment AC. The position of the 16th vertex ADD is off the third line segment AD. The distance between the 14th vertex ACC and the 16th vertex ADD in the X direction is narrower.

[0146] Due to this configuration, the opening area of ​​the first communication hole 751 gradually narrows as you move from the first refrigerant passage 710 towards the second communication hole 752. Conversely, the area of ​​the second front surface 723 gradually widens as you move from the first refrigerant passage 710 towards the second communication hole 752.

[0147] <Ninth Embodiment> The connection configuration between the first communication hole 751 and the first refrigerant passage 710 can be, for example, the configuration shown in Figures 17 to 19.

[0148] The flow region 720R shown in Figure 17 is equivalent to that of the fifth embodiment. In this configuration, the wall that partitions the first refrigerant passage 710 extends from the 14th vertex ACC, the 16th vertex ADD, the 18th vertex BDD, and the 17th vertex BCC.

[0149] The flow region 720R shown in Figure 18 is equivalent to that of the eighth embodiment. In this configuration, the wall that partitions the first refrigerant passage 710 extends from the 14th vertex ACC, the 16th vertex ADD, the 18th vertex BDD, and the 17th vertex BCC.

[0150] The flow region 720R shown in Figure 19 differs from that of the eighth embodiment. In the configuration shown in Figure 19, the flow region 720R does not have the 14th vertex ACC and the 16th vertex ADD. Instead, the flow region 720R has the 21st vertex ACD. This 21st vertex ACD lies on a quadrilateral formed by connecting the 13th vertex ACA, the 15th vertex ADA, the 4th vertex D, and the 3rd vertex C in order. The position of the 21st vertex ACD in the Y direction is between the 13th vertex ACA and the 3rd vertex C, and between the 15th vertex ADA and the 4th vertex D. The position of the 21st vertex ACD in the Z direction is between the 13th vertex ACA and the 3rd vertex C, and between the 15th vertex ADA and the 4th vertex D.

[0151] The first communication hole 751 is represented by a triangle formed by connecting the 21st vertex ACD, the 4th vertex D, and the 3rd vertex C. In this configuration, the wall that partitions the first refrigerant passage 710 extends from the 21st vertex ACD, the 4th vertex D, and the 3rd vertex C.

[0152] <Other variations> The disclosure in this specification is not limited to the exemplary embodiments. The disclosure encompasses the exemplary embodiments and variations thereof by those skilled in the art. For example, the disclosure is not limited to the combinations of parts and elements shown in the embodiments, but can be implemented in various variations. The disclosure can be implemented in a variety of combinations. The disclosure may have additional parts that can be added to the embodiments. The disclosure encompasses embodiments in which parts and elements have been omitted. The disclosure encompasses substitutions or combinations of parts and elements between one embodiment and another. The scope of the disclosed technical field is not limited to the descriptions of the embodiments. The scope of the disclosed technical field is indicated by the claims and should be understood to include all modifications within the meaning and scope equivalent to the claims.

[0153] In this embodiment, an example is shown in which the power converter 300 is used in the in-vehicle system 100 of an electric vehicle. However, the use of the power converter 300 is not limited to the above example. The power converter 300 can be appropriately used in hybrid vehicles, trucks, drones, robots, and home appliances, etc.

[0154] In this embodiment, the case 600 is shown as housing and cooling the power conversion circuit 500. However, these two functions of housing and cooling may be separated. That is, the case 600 may only house the power conversion circuit 500. A separate component from the case 600 may be configured as a cooler having a refrigerant passage 700 for cooling the power conversion circuit 500.

[0155] <Disclosure of Technical Ideas> This specification discloses several technical concepts, as listed in the following paragraphs. Some paragraphs are written in a multiple dependent form, where subsequent paragraphs optionally refer to preceding paragraphs. Furthermore, some paragraphs are written in a multiple dependent form, referring to other multiple dependent forms. These paragraphs written in multiple dependent forms define several technical concepts.

[0156] <Technical philosophy 1> A cooler comprising a first cooling channel (710) for cooling a first component (521) included in a power conversion circuit (500), and a second cooling channel (730) for cooling a second component (543) included in the power conversion circuit, with a connecting channel (720) connecting them, The first cooling channel and the second cooling channel extend in a vertical direction perpendicular to the vertical direction, The second cooling channel is located above the first cooling channel in the vertical direction and is spaced apart from the first cooling channel in the longitudinal direction. The aforementioned communication channel is divided by connecting surfaces (725, 726, 727) that connect an inlet (751) into which the refrigerant flowing through the first cooling channel flows, and an outlet (752) located above the inlet in the vertical direction and spaced apart in the vertical direction, which allows the refrigerant that has flowed into the inlet to flow out into the second cooling channel. A portion of the connecting surface is a slope (726c) in which the vertical distance from the outlet gradually changes as it approaches the outlet from the inlet in the vertical direction. The outlet of the cooler is longer in the vertical direction than in the horizontal direction which is perpendicular to the vertical direction. <Technical philosophy 2> The outlet is divided by a first edge (752a) and a second edge (752b) that are spaced apart in the lateral direction, and a third edge (752c) and a fourth edge (752d) that are spaced apart in the vertical direction. The second cooling channel extends in the longitudinal direction from the third edge to the fourth edge, The fourth edge is shorter in the lateral direction than the third edge. The cooler according to technical idea 1, wherein at least one of the first edge and the second edge is inclined such that the distance between it and the other of the first edge and the second edge in the lateral direction gradually decreases as it moves from the third edge to the fourth edge in the longitudinal direction. <Technical philosophy 3> The vertical distance between the slope and the outlet gradually decreases as you move from the inlet towards the outlet in the longitudinal direction. A cooler according to technical concept 1 or technical concept 2, wherein the inlet and the slope are aligned in the vertical direction. <Technical philosophy 4> The cooler according to technical concept 3, wherein the shortest vertical separation distance between the outlet and the slope is shorter than the vertical length of the inlet. <Technical philosophy 5> A cooler according to any one of the technical concepts 1 to 4, wherein the cross-sectional area of ​​the communication channel is narrower on the outlet side than on the inlet side. <Technical philosophy 6> The aforementioned communication channel is An inclined space (720a) that is inclined with respect to the vertical direction such that, in the vertical direction, as you approach the outlet from the inlet, the vertical distance between you and the outlet gradually decreases, In the aforementioned vertical direction, a rear space (720c) is aligned with the inclined space via the aforementioned slope, A cooler according to any one of technical ideas 1 to 5, having an upper space (720b) ​​located between the inclined space and the rear space in the vertical direction, and connecting the inclined space and the rear space. <Technical philosophy 7> A cooler according to any one of the technical concepts 1 to 6, wherein some of the multiple heat dissipation fins (738) provided in the second cooling channel are aligned with the outlet in the vertical direction. <Technical philosophy 8> The cooler according to any one of technical ideas 1 to 7, wherein a flow straightening section (728) extending in the direction connecting the inlet and the outlet is formed on the slope. <Technical philosophy 9> A cooler according to any one of the technical concepts 1 to 8 for housing the aforementioned power conversion circuit. <Technical Thought 10> Power conversion circuit (500), A power conversion device having a cooler (600) for cooling the power conversion circuit, The power conversion circuit has a first component (521) and a second component (543), The cooler comprises a first cooling channel (710) for cooling the first component, a second cooling channel (730) for cooling the second component, and a connecting channel (720) that connects the first cooling channel and the second cooling channel. The first cooling channel and the second cooling channel extend in a vertical direction perpendicular to the vertical direction, The second cooling channel is located above the first cooling channel in the vertical direction and is spaced apart from the first cooling channel in the longitudinal direction. The aforementioned communication channel is divided by connecting surfaces (725, 726, 727) that connect an inlet (751) into which the refrigerant flowing through the first cooling channel flows, and an outlet (752) located above the inlet in the vertical direction and spaced apart in the vertical direction, which allows the refrigerant that has flowed into the inlet to flow out into the second cooling channel. A portion of the connecting surface is a slope (726c) in which the vertical distance from the outlet gradually changes as it approaches the outlet from the inlet in the vertical direction. The outlet of the power conversion device is longer in the vertical direction than in the horizontal direction which is perpendicular to the vertical direction and the longitudinal direction. [Explanation of symbols]

[0157] 100…In-vehicle system, 200…Battery, 300…Power converter, 400…Motor, 500…Power conversion circuit, 521…Capacitor case, 543…Switch case, 600…Case, 710…First refrigerant passage, 720…Second refrigerant passage, 720a…Inclined space, 720b…Upper space, 720c…Rear space, 725…Second top surface, 726…Second bottom surface, 726c…Inclined surface, 727…Second annular surface, 728…Rectifier plate, 730…Third refrigerant passage, 738…Heat dissipation fin, 751…First communication hole, 752…Second communication hole, 752a…Left edge, 752b…Right edge, 752c…Front edge, 752d…Rear edge

Claims

1. A cooler comprising a first cooling channel (710) for cooling a first component (521) included in a power conversion circuit (500), and a second cooling channel (730) for cooling a second component (543) included in the power conversion circuit, with a connecting channel (720) connecting them, The first cooling channel and the second cooling channel extend in a vertical direction perpendicular to the vertical direction, The second cooling channel is located above the first cooling channel in the vertical direction and is spaced apart from the first cooling channel in the longitudinal direction. The aforementioned communication channel is divided by connecting surfaces (725, 726, 727) that connect an inlet (751) into which the refrigerant flowing through the first cooling channel flows, and an outlet (752) located above the inlet in the vertical direction and spaced apart in the vertical direction, which allows the refrigerant that has flowed into the inlet to flow out into the second cooling channel. A portion of the connecting surface is a slope (726c) in which the vertical distance from the outlet gradually changes as it approaches the outlet from the inlet in the vertical direction. The outlet of the cooler is longer in the vertical direction than in the horizontal direction which is perpendicular to the vertical direction.

2. The outlet is divided by a first edge (752a) and a second edge (752b) that are spaced apart in the lateral direction, and a third edge (752c) and a fourth edge (752d) that are spaced apart in the vertical direction. The second cooling channel extends in the longitudinal direction from the third edge to the fourth edge, The fourth edge portion has a shorter lateral length than the third edge portion. The cooler according to claim 1, wherein at least one of the first edge and the second edge is inclined such that the distance between it and the other of the first edge and the second edge in the lateral direction gradually decreases as it moves from the third edge to the fourth edge in the vertical direction.

3. The vertical distance between the slope and the outlet gradually decreases as you move from the inlet towards the outlet in the longitudinal direction. The cooler according to claim 1 or claim 2, wherein the inlet and the slope are aligned in the vertical direction.

4. The cooler according to claim 3, wherein the shortest vertical separation distance between the outlet and the slope is shorter than the vertical length of the inlet.

5. The cooler according to claim 1 or claim 2, wherein the cross-sectional area of ​​the communication channel is narrower on the outlet side than on the inlet side.

6. The aforementioned communication channel is An inclined space (720a) that is inclined with respect to the vertical direction such that, in the vertical direction, as one approaches the outlet from the inlet, the vertical distance between the inlet and the outlet gradually decreases; In the aforementioned vertical direction, a rear space (720c) is aligned with the inclined space via the aforementioned slope, The cooler according to claim 1 or claim 2, having an upper space (720b) ​​located between the inclined space and the rear space in the vertical direction, and connecting the inclined space and the rear space.

7. The cooler according to claim 1 or claim 2, wherein some of the multiple heat dissipation fins (738) provided in the second cooling channel are aligned with the outlet in the vertical direction.

8. The cooler according to claim 1 or claim 2, wherein a flow straightening section (728) extending in the direction connecting the inlet and the outlet is formed on the slope.

9. A cooler according to claim 1 or claim 2, which houses the power conversion circuit.

10. Power conversion circuit (500), A power conversion device having a cooler (600) for cooling the power conversion circuit, The power conversion circuit has a first component (521) and a second component (543), The cooler includes a first cooling channel (710) for cooling the first component, a second cooling channel (730) for cooling the second component, and a connecting channel (720) that connects the first cooling channel and the second cooling channel. The first cooling channel and the second cooling channel extend in a vertical direction perpendicular to the vertical direction, The second cooling channel is located above the first cooling channel in the vertical direction and is spaced apart from the first cooling channel in the longitudinal direction. The aforementioned communication channel is divided by connecting surfaces (725, 726, 727) that connect an inlet (751) into which the refrigerant flowing through the first cooling channel flows, and an outlet (752) located above the inlet in the vertical direction and spaced apart in the vertical direction, which allows the refrigerant that has flowed into the inlet to flow out into the second cooling channel. A portion of the connecting surface is a slope (726c) in which the vertical distance from the outlet gradually changes as it approaches the outlet from the inlet in the vertical direction. The outlet of the power conversion device is longer in the vertical direction than in the horizontal direction which is perpendicular to the vertical direction and the longitudinal direction.

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