Oil pool elimination device

Abstract

To prevent compressor oil circulating with a refrigerant from staying inside a cooling plate 4.SOLUTION: An oil pool elimination device according to the present disclosure includes a cooling plate and a return pipe. The cooling plate includes a housing, an inlet, a flow path, and an outlet. A heat radiation object is thermally connected to the housing. The inflow port is connected to a pipe on a high pressure side of an air conditioning system in which a refrigerant circulates, and the refrigerant is supplied from the pipe on the high pressure side. The flow path is formed inside the housing, and the refrigerant flowing in from the inflow port flows through the flow path. The outflow port is connected to a low-pressure side pipe of the air conditioning system, and discharges the refrigerant that has exchanged heat with the housing in the flow path to the low-pressure side pipe. The return pipe spatially connects the inflow port and the outflow port of the cooling plate with a flow path cross section smaller than flow path cross sections of the inflow port and the outflow port outside the housing of the cooling plate.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an oil pool elimination device. [Background technology]

[0002] Conventionally, power conversion devices such as on-board chargers and DC-DC converters installed in electric vehicles convert large currents and high voltages. As the control frequency of such power conversion devices increases, they become smaller, but heat dissipation from the heat-generating components installed in them becomes an issue.

[0003] For example, Patent Document 1 discloses a technology in which a battery module is connected to a heat exchanger via a coolant circulation circuit, the heat exchanger is connected to a temperature control device via a refrigerant circulation circuit, the refrigerant in the refrigerant circulation circuit is cooled using the cooling function of the temperature control device, and the refrigerant in the refrigerant circulation circuit and the coolant in the coolant circulation circuit are heat exchanged in the heat exchanger, thereby cooling the battery module with the coolant in the coolant circulation circuit. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6014602 Summary of the Invention [Problem to be solved by the invention]

[0005] For example, cooling may be performed by placing a heat-generating component to be dissipated on a plate-shaped heat exchanger (cooling plate) with internal flow channels. In such cases, in order to improve the cooling capacity of the cooling plate, it is preferable to use a refrigerant, which can utilize the latent heat generated by a phase change, as the working fluid instead of a coolant such as water. However, when using a refrigerant as the working fluid, compressor oil circulates along with the refrigerant, which creates a problem of oil accumulating in the flow channels of the cooling plate, which causes a large pressure loss.

[0006] One of the problems that the present disclosure aims to solve is to prevent compressor oil, which circulates together with the refrigerant, from accumulating inside the cooling plate. [Means for solving the problem]

[0007] The oil accumulation elimination device according to the present disclosure comprises a cooling plate and a return pipe. The cooling plate has a housing, an inlet, a flow path, and an outlet. The housing is thermally connected to a heat dissipation target. The inlet is connected to a high-pressure side pipe of an air conditioning system through which a refrigerant circulates, and the refrigerant is supplied from the high-pressure side pipe. The flow path is formed inside the housing, and the refrigerant that flows in from the inlet flows through the flow path. The outlet is connected to a low-pressure side pipe of the air conditioning system, and discharges the refrigerant that has exchanged heat with the housing in the flow path into the low-pressure side pipe. The return pipe spatially connects the inlet and outlet of the cooling plate, outside the housing of the cooling plate, with a flow path cross-section smaller than the flow path cross-sections of the inlet and the outlet. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to prevent the accumulation of compressor oil circulating with the refrigerant inside the cooling plate. Note that the effects described herein are not necessarily limited to those described herein, and any of the effects described in this specification may be achieved. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a cooling system according to an embodiment. [Figure 2] FIG. 2 is a perspective view showing an example of the configuration of the cooling plate of FIG. [Figure 3] FIG. 3 is a diagram illustrating an example of the internal configuration of the cooling plate of FIG. [Figure 4] FIG. 4 is a diagram showing an example of the configuration of an oil pool elimination device applied to the cooling plate of FIG. [Figure 5] FIG. 5 is a diagram showing an example of the configuration of the oil pool elimination device of FIG. [Figure 6] FIG. 6 is a diagram showing another example of the configuration of the oil pool elimination device of FIG. [Figure 7] FIG. 7 is a diagram showing another example of the configuration of the oil pool elimination device applied to the cooling plate of FIG. [Figure 8] FIG. 8 is a diagram showing an example of the configuration of the relay block of the oil pool elimination device of FIG. [Figure 9] FIG. 9 is a diagram showing an example of the configuration of the relay block of the oil pool elimination device of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of an oil pool elimination device, a cooling device, a power conversion device, and a vehicle according to the present disclosure will be described with reference to the drawings.

[0011] In the description of the present disclosure, components having the same or substantially the same functions as those described above with respect to the previously-mentioned drawings may be given the same reference numerals, and descriptions thereof may be omitted as appropriate. Furthermore, even when the same or substantially the same parts are shown, the dimensions and proportions may differ depending on the drawing. Furthermore, for example, in order to ensure the visibility of the drawings, reference numerals may be given to only the main components in the description of each drawing, and reference numerals may not be given to components having the same or substantially the same functions as those described above with respect to the previously-mentioned drawings.

[0012] In the description of this disclosure, expressions such as orthogonal, horizontal, vertical, parallel, identical, coincident, and the same position are not limited to cases where they are strictly orthogonal, horizontal, vertical, parallel, identical, coincident, or the same position, but also include cases where they can be considered to be orthogonal, horizontal, vertical, parallel, identical, coincident, or the same position.

[0013] (First embodiment) 1 is a diagram showing an example of the configuration of a cooling system 1 according to an embodiment. The cooling system 1 according to the embodiment is a system that is applied to, for example, a vehicle (moving body) and is configured to be able to cool heat-generating parts of the vehicle.

[0014] A cooling system 1 according to the embodiment is applied to an air conditioning system 2 mounted on, for example, a vehicle. As shown in FIG. 1, the air conditioning system 2 includes a compressor 21, a condenser 22, an expansion valve 23, an evaporator 24, and a pipe 29.

[0015] The compressor 21 is a device (compressor) that adiabatically compresses the refrigerant circulating inside the piping, and generates and discharges a high-temperature, high-pressure refrigerant (gas). The compressor 21 may be water-cooled or air-cooled. The compressor 21 is, for example, an oil-lubricated compressor, and the refrigerant (gas) that is discharged contains oil mist. That is, in the cooling system 1 according to this embodiment, the refrigerant circulates inside the piping 29 together with compressor oil.

[0016] The condenser 22 is a heat exchanger (condenser) that is provided in the subsequent stage of the compressor 21 and liquefies the high-temperature, high-pressure refrigerant (gas) from the compressor 21 by radiating heat and condensing it. The condenser 22 may be an air-cooled type, a water-cooled type, or an evaporative type.

[0017] The expansion valve 23 is a device (throttle valve) that is provided in the subsequent stage of the condenser 22 and adiabatically expands (decompresses and expands) the high-pressure refrigerant (liquid) from the condenser 22, i.e., generates a low-temperature, low-pressure refrigerant (gas / liquid) by adiabatic cooling. Note that the refrigeration cycle that realizes the air conditioning system 2 may be configured as a cycle that can recover part of the power by using a positive displacement or turbine expander as the expansion valve 23.

[0018] The evaporator 24 is a heat exchanger (evaporator) that is provided after the expansion valve 23 and vaporizes the low-temperature, low-pressure refrigerant (gas / liquid) from the expansion valve 23. The evaporator 24 may be an air-cooled type, a water-cooled type, or an evaporation type. The evaporator 24 may be a dry type evaporator in which the refrigerant becomes completely gas at the outlet, or a liquid-filled type evaporator in which liquid refrigerant is always present in the evaporator 24.

[0019] The pipe 29 connects the compressor 21, the condenser 22, the expansion valve 23, and the evaporator 24, and is a flow path through which the refrigerant circulates.

[0020] In this embodiment, the air conditioning system 2 has at least a cooling function, but is not limited to this. The air conditioning system 2 may have a heating function in addition to the cooling function. For example, the air conditioning system 2 realizes the cooling function of cooling the air in the vehicle cabin by utilizing heat absorption in the evaporator 24, but may also realize the heating function of heating the air in the vehicle cabin by utilizing heat dissipation in the condenser 22, that is, by operating as a heat pump.

[0021] In the air conditioning system 2, an oil separator that separates oil from the refrigerant gas discharged from the compressor 21 may be provided downstream of the compressor 21. Furthermore, a receiver that absorbs fluctuations in the amount of refrigerant in the pipe 29 may be provided inside or downstream of the condenser 22.

[0022] The air conditioning system 2 according to the embodiment may have a plurality of compressors 21 and expansion valves 23 depending on, for example, the required cooling capacity.

[0023] In the air conditioning system 2 according to the embodiment, HFCs (hydrofluorocarbons) such as R410A and R32 are used as the refrigerant, but HFOs (hydrofluoroolefins) such as HFO-1234yf, CO2, etc. may also be used.

[0024] The cooling system 1 according to the embodiment may be configured as a system independent of the air conditioning system 2 mounted on a vehicle or the like. Alternatively, the cooling system 1 according to the embodiment may be configured as a system that shares at least one of the compressor 21, the condenser 22, the expansion valve 23, the evaporator 24, and the piping 29.

[0025] 1, the cooling system 1 also includes a cooling plate 4. The cooling plate 4 is provided, for example, between the evaporator 24 and the compressor 21, and is connected to the evaporator 24 and the compressor 21 by piping 29. That is, in the cooling system 1 applied to the air conditioning system 2, the refrigerant circulates inside the piping 29 in the order of the compressor 21 → the condenser 22 → the expansion valve 23 → the evaporator 24 → the cooling plate 4 → the compressor 21.

[0026] Fig. 2 is a perspective view showing an example of the configuration of the cooling plate 4 of Fig. 1. Fig. 3 is a view showing an example of the internal configuration of the cooling plate 4 of Fig. 1.

[0027] The cooling plate 4 is a cooling member formed into a plate shape from a metal material such as die-cast. The cooling plate 4 has a cooling structure that uses the refrigerant circulating through the air conditioning system 2 as a working fluid. Specifically, the cooling plate 4 has a cooling structure that cools a cooling target (heat dissipation target) thermally connected to its housing 401. As shown in FIGS. 2 and 3 , the cooling plate 4 has an inlet 41, a flow path 43, and an outlet 45.

[0028] The inlet 41 is connected to the outlet of the evaporator 24 via the pipe 29. The inlet 41 connects the pipe 29 to a flow path 43 of the cooling plate 4. The refrigerant from the evaporator 24 is supplied to the inlet 41.

[0029] The flow path 43 is a flow path for the refrigerant formed inside the housing 401. The flow path 43 extends in a direction along the cooling surface (XY plane) of the cooling plate 4. In other words, the housing 401 of the cooling plate 4 has the flow path 43 formed therein, running within a single plane along the cooling surface. The shape of the flow path in the plane perpendicular to the flow of the flow path 43 is different from, for example, the shape of the pipe 29, the inlet 41, and the outlet 45.

[0030] Note that the flow paths 43 may branch in at least two directions within a single plane along the cooling surface. However, the flow paths do not branch in a direction perpendicular to the cooling surface (Z direction). In other words, when flow paths 43 are provided with flow paths in at least two directions and an intersection exists where the flow paths in the two directions intersect, each flow path extends from the intersection in a direction parallel to the cooling surface but does not extend in a direction perpendicular to the cooling surface. In this way, the cooling mechanism of the entire system of the cooling plate 4 according to the present disclosure is configured by flow paths 43 that run only within a single plane inside the housing 401.

[0031] In the cooling system 1 according to the present disclosure, the direction along the cooling surface (X direction and Y direction) is, for example, the horizontal direction. Furthermore, the direction perpendicular to the cooling surface (Z direction) is, for example, the direction of gravity. Of course, these directions are merely examples, and the Z direction may be inclined relative to the direction of gravity. Alternatively, either the X direction or the Y direction may be the direction of gravity.

[0032] The outlet 45 is connected to the inlet of the compressor 21 via the pipe 29. The outlet 45 connects the pipe 29 to the flow path 43 of the cooling plate 4. The refrigerant that has passed through the flow path 43 of the cooling plate 4 is discharged from the outlet 45 and supplied to the compressor 21.

[0033] As an example, in a cooling system 1 applied to a vehicle, the housing 401 of the cooling plate 4 is thermally connected to the heat-generating parts of the vehicle, and transports heat from the heat-generating parts of the vehicle to the outside of the cooling plate 4 via a refrigerant.

[0034] 2 illustrates a case where an on-board charger 6 serving as a heat-generating part of a vehicle is disposed in a housing 401. In the example of FIG. 2, a circuit board 61 of the on-board charger 6 and a transformer 63 and an electrolytic capacitor 65 disposed on the circuit board 61 are thermally connected to the housing 401. The transformer 63 and the electrolytic capacitor 65 may be thermally connected to the cooling plate 4 via the circuit board 61, or may be thermally connected to the cooling plate 4 directly without the circuit board 61.

[0035] The heat-generating part of the vehicle may be, for example, a power conversion device such as an on-board charger or a DC-DC converter, but may also be a battery, electrical equipment, etc. Furthermore, the power conversion device is not limited to being mounted on a vehicle (mobile object) such as an electric vehicle, but may also be mounted on other devices of the mobile object, such as a charging device at a charging station, amusement equipment, or an uninterruptible power supply. For example, the on-board charger may be a power conversion device that converts AC power supplied from a single-phase or three-phase AC power source external to the vehicle into DC power and supplies the converted DC power to a load mounted on the vehicle. This load may be, for example, a battery, an inverter, a motor, various electrical equipment, etc.

[0036] The cooling system 1 according to the present disclosure may be applied to a mobile body such as a passenger car, a freight vehicle, a passenger van, a motorcycle, an electric kick scooter, construction machinery, agricultural machinery, or an aircraft.

[0037] Furthermore, examples of electrical equipment for a mobile object include a navigation system, an audio system, an air conditioner, a power window, a defogger, an ECU (Electronic Control Unit), a GPS (Global Positioning System) module, and a camera.

[0038] Furthermore, the battery for the mobile body only needs to be capable of storing power to drive the travel motor (main motor) and electrical equipment mounted on the mobile body, and any battery can be used as appropriate, such as a lithium-ion battery, a nickel-metal hydride battery, or an all-solid-state battery.

[0039] For example, an on-board charger may be provided with a noise filter that suppresses (removes) noise from entering the on-board charger from an external AC power source and from exiting the on-board charger to the AC power source. Furthermore, for example, a power conversion circuit is provided downstream of the noise filter to convert AC power supplied from an external single-phase or three-phase AC power source through the noise filter into DC power and output the converted DC power to the battery. This power conversion circuit may be provided with a power factor correction (PFC) circuit that rectifies and smooths the AC voltage from the external AC power source after noise removal by the noise filter to generate a DC voltage. Furthermore, for example, a DC-DC converter is provided downstream of the PFC circuit in the power conversion circuit to convert the DC voltage generated by the PFC circuit back into AC voltage and then rectifies and smooths the converted AC voltage to generate a DC voltage of an arbitrary set voltage.

[0040] Each component of an on-board charger, such as a noise filter, PFC circuit, or DC-DC conversion circuit, includes magnetic components such as a transformer, a transformer-integrated printed circuit board, various inductors such as chokes, reactors, or assemblies that include these. A coil device equipped with magnetic components such as an on-board charger, a noise filter, a PFC circuit, or a DC-DC conversion circuit (DC-DC converter) generates a lot of heat when converting high-current or high-voltage power. Such a coil device or its magnetic components are an example of a cooling target (heat dissipation target) by the cooling system 1 according to the present disclosure, and are also an example of a heat-generating part of a vehicle.

[0041] For example, when a heat-generating component to be dissipated is placed on the cooling plate 4 having the flow paths 43 formed therein and cooled, it is preferable to use a refrigerant that can utilize the latent heat generated during a phase change as the working fluid, from the viewpoint of improving the cooling capacity of the cooling plate 4. However, in cooling using a refrigerant as the working fluid, compressor oil circulates along with the refrigerant, and there is a problem that oil tends to accumulate in the flow paths 43 of the cooling plate 4 due to pressure loss and a decrease in pressure and flow rate caused by the routing of the flow paths 43.

[0042] Furthermore, the flow paths 43 provided for cooling are expanded, for example, along the cooling surface (XY plane) in order to increase the heat transfer area. Alternatively, in order to increase the length within the cooling plate 4, for example, the flow path cross section is reduced and routed within the cooling plate 4. In this way, the shape of the flow paths 43 differs from the shapes of, for example, the pipes 29, the inlet 41, and the outlet 45, for example, in a plane perpendicular to the flow. For this reason, there has been a problem in that oil is likely to accumulate within the flow paths 43 of the cooling plate 4 due to pressure loss and a decrease in pressure and flow rate caused by the routing of the flow paths 43.

[0043] Furthermore, the amount of compressor oil circulating with the refrigerant (circulation amount) is designed so that a certain amount of oil remains inside the compressor 21. Therefore, if oil accumulates on the cooling plate 4, the circulation amount decreases, which could cause the compressor 21 to seize. On the other hand, if the circulation amount is designed to be large, the energy required for circulation increases, which could result in increased power consumption or reduced cooling efficiency.

[0044] Therefore, the cooling system 1 according to the present disclosure is provided with an oil pool elimination device 5 that prevents compressor oil circulating together with the refrigerant from accumulating inside the cooling plate 4. Specifically, the oil pool elimination device 5 is applied to the cooling plate 4 in the cooling system 1 according to the present disclosure.

[0045] Fig. 4 is a diagram showing an example of the configuration of the oil pool elimination device 5 applied to the cooling plate 4 of Fig. 1. Fig. 5 is a diagram showing an example of the configuration of the oil pool elimination device 5 of Fig. 4.

[0046] 4 and 5, the oil accumulation elimination device 5 according to this embodiment has a return pipe 51. The return pipe 51 connects the inlet 41 and the outlet 45.

[0047] 4, length H1 of inlet 41 protruding from housing 401 in the Z direction is longer than length H2 of outlet 45 protruding from housing 401 in the Z direction. In other words, inlet 41 is located higher than outlet 45 in, for example, the direction of gravity (Z direction).

[0048] The inlet 41 and the outlet 45 have a pipe diameter of, for example, about 13 to 16 mm. On the side of the inlet 41 facing the outlet 45 and on the side of the outlet 45 facing the inlet 41, holes having a diameter of, for example, about 1 to 3 mm are provided, respectively.

[0049] The return pipe 51 is connected to the holes of the inlet 41 and the outlet 45 by, for example, brazing. The return pipe 51 is a pipe having a flow path cross section with a diameter of, for example, about 1 to 3 mm. As a result, the return pipe 51 spatially connects the inlet 41 and the outlet 45 with a cross section area smaller than that of each pipe.

[0050] The return pipe 51 has, for example, a circular cross-sectional shape, but may have other cross-sectional shapes such as an oval or a rectangle.

[0051] As a result, oil is forced out from the high-pressure side inlet 41 to the low-pressure side outlet 45. The oil forced out to the outlet 45 is discharged to the outside of the cooling plate 4 together with the refrigerant flowing out from the flow path 43.

[0052] In this way, the cooling plate 4 to which the oil accumulation elimination device 5 is applied can reduce the amount of compressor oil flowing into the flow path 43 because oil is sucked out from the inlet 41 to the outlet 45. In other words, the cooling system 1 according to the embodiment can prevent the compressor oil circulating together with the refrigerant from accumulating inside the cooling plate 4.

[0053] Hereinafter, another embodiment of the cooling system 1 according to the present disclosure will be described with reference to the drawings. Note that the following description will mainly focus on differences from the above-described embodiment, and redundant description will be omitted as appropriate.

[0054] (Second embodiment) The configuration of the oil pool elimination device 5 is not limited to the example shown in Fig. 5 and can be modified as appropriate. Fig. 6 is a diagram showing another example of the configuration of the oil pool elimination device 5 shown in Fig. 4.

[0055] 6, the oil accumulation elimination device 5 according to this embodiment has a return pipe 53. The return pipe 53 connects the inlet 41 and the outlet 45.

[0056] Holes having a diameter of, for example, about 1 to 3 mm are provided below the inlet 41 in the direction of gravity (-Z side) and on the inlet 41 side of the outlet 45. The return pipe 53 is connected to the holes of the inlet 41 and the outlet 45 by, for example, brazing. The return pipe 53 is a pipe having a flow path cross section with a diameter of, for example, about 1 to 3 mm. As a result, the return pipe 53, like the return pipe 51, spatially connects the inlet 41 and the outlet 45 with a cross section area smaller than that of each pipe.

[0057] As shown in FIG. 6, the return pipe 53 includes an oil trap 531 and a pipe 533 .

[0058] Oil trap 531 is provided below in the direction of gravity (-Z side) of inlet 41. Oil trap 531 is formed, for example, by a conduit extending downward from a hole provided below in the direction of gravity (-Z side) of inlet 41. Conduit 533 spatially connects the below in the direction of gravity (-Z side) of oil trap 531 and the hole of outlet 45. Conduit 533 is formed so that the cross section of the flow path becomes smaller from the oil trap 531 side toward outlet 45 side.

[0059] Although the oil trap 531 and the pipe 533 each have a circular cross-sectional shape, for example, they may have other cross-sectional shapes such as an oval or a rectangle.

[0060] The oil trap 531 may be formed so that the cross section of the flow path becomes smaller from the hole of the inlet 41 downward in the direction of gravity (toward the −Z side).

[0061] The cross section of the conduit 533 decreases uniformly from the oil trap 531 toward the outlet 45, but is not limited to this. A part or the whole of the conduit 533 may have a constant cross section, similar to the return pipe 51.

[0062] Even with this configuration, oil can be sucked from the inlet 41 on the high-pressure side to the outlet 45 on the low-pressure side, and the amount of compressor oil flowing into the flow path 43 can be reduced.

[0063] Furthermore, by providing an oil trap 531 below the inlet 41 in accordance with the oil falling in the direction of gravity, the oil can be efficiently discharged from the inlet 41 on the high-pressure side.

[0064] Furthermore, by configuring the inlet 41 and the outlet 45 to be spatially connected by a conduit 533 whose flow path cross section gradually becomes smaller, oil is more easily pushed out to the outlet 45, thereby further reducing the amount of compressor oil flowing into the flow path 43.

[0065] The oil pool elimination device 5 according to this embodiment is applicable to the cooling system 1 according to the first embodiment. For example, in the cooling plate 4 according to the first embodiment, the return pipe 51 may be formed so that the cross section of the flow path becomes smaller from the inlet 41 toward the outlet 45, similar to the pipe 533 of the oil pool elimination device 5 according to the second embodiment.

[0066] (Third embodiment) The configuration of the oil pool elimination device 5 is not limited to the examples in Figures 5 and 6 and can be modified as appropriate. Figure 7 is a diagram showing another example of the configuration of the oil pool elimination device 5 applied to the cooling plate 4 in Figure 1. Figure 8 is a diagram showing an example of the configuration of the relay block 55 of the oil pool elimination device 5 in Figure 7. Figure 9 is a diagram showing an example of the configuration of the relay block 55 of the oil pool elimination device 5 in Figure 7.

[0067] 7, the oil accumulation elimination device 5 according to this embodiment has a relay block 55. The relay block 55 has, for example, a rectangular parallelepiped shape. The relay block 55 has, for example, a structure similar to the return pipe 53 formed therein.

[0068] 7, the relay block 55 is connected to the cooling plate 4. Specifically, the relay block 55 has an inlet-side connection part 551 connected to the inlet 41 of the cooling plate 4, and an outlet-side connection part 552 connected to the outlet 45 of the cooling plate 4.

[0069] 8, the inlet-side connection portion 551 and the outlet-side connection portion 552 are provided, for example, on one surface (the YZ surface on the -X side) of the relay block 55. The inlet-side connection portion 551 and the outlet-side connection portion 552 are positioned differently in the gravity direction (Z direction) on the relay block 55. Specifically, the inlet-side connection portion 551 and the outlet-side connection portion 552 are positioned differently in the gravity direction (Z direction) by a length L1 that is the difference between lengths H1 and H2, in accordance with lengths H1 and H2 of the inlet 41 and the outlet 45 of the cooling plate 4 that protrude from the housing 401 in the Z direction.

[0070] 9, a relay block side inlet 553 is provided on the surface (YZ surface) of the relay block 55 opposite (+X side) to the inlet side connection portion 551. The relay block side inlet 553 is connected to the outlet of the evaporator 24 via the piping 29. Refrigerant from the evaporator 24 is supplied to the relay block side inlet 553. Inside the relay block 55, the inlet side connection portion 551 and the relay block side inlet 553 are spatially connected by the inlet side flow path 555. That is, the relay block 55 connects the inlet 41 of the cooling plate 4 as well as the piping 29 and the flow path 43 of the cooling plate 4.

[0071] As shown in FIG. 9, the inlet-side flow path 555 has a first flow path 555a, a second flow path 555b, and a third flow path 555c. The first flow path 555a is a flow path that extends from the relay-block-side inlet 553 to the second flow path 555b in the −X direction inside the relay block 55. The second flow path 555b is a flow path that extends in the gravity direction (Z direction) inside the relay block 55. The second flow path 555b is spatially connected to the −X-side end of the first flow path 555a inside the relay block 55. The third flow path 555c is a flow path that extends from the inlet-side connection part 551 to the second flow path 555b in the +X direction inside the relay block 55. The third flow path 555c is spatially connected to the upper end of the second flow path 555ab in the gravity direction (Z direction) inside the relay block 55. In other words, the second flow path 555b is spatially connected to the +X side end of the third flow path 555c inside the relay block 55. In further other words, the second flow path 555b spatially connects the first flow path 555a and the third flow path 555c inside the relay block 55.

[0072] Similarly, a relay block side outlet 554 is provided on the surface (YZ surface) of the relay block 55 opposite (+X side) to the outlet side connection portion 552. The relay block side outlet 554 is connected to the inlet of the compressor 21 via the piping 29. Inside the relay block 55, the outlet side connection portion 552 and the relay block side outlet 554 are spatially connected by an outlet side flow path 556. The outlet side flow path 556 is a flow path that extends from the outlet side connection portion 552 to the relay block side outlet 554 in the +X direction inside the relay block 55. In other words, the relay block 55 connects the piping 29 and the flow path 43 of the cooling plate 4 together with the outlet 45 of the cooling plate 4. The refrigerant that has passed through the flow path 43 of the cooling plate 4 is discharged via the relay block 55 and supplied to the compressor 21.

[0073] The inlet-side connecting portion 551, the outlet-side connecting portion 552, the relay block-side inlet 553, and the relay block-side outlet 554 have, for example, the same pipe diameter as the inlet 41 and the outlet 45. Also, holes having a diameter of, for example, about 1 to 3 mm are provided on the side of the outlet-side flow path 556 below the connection portion of the second flow path 555b (inlet-side flow path 555) with the first flow path 555a, and on the side of the outlet-side flow path 556 on the second flow path 555b (inlet-side flow path 555).

[0074] 9, a return pipe 557 is formed inside the relay block 55. The return pipe 557 is connected to holes in the inlet-side flow path 555 and the outlet-side flow path 556. The return pipe 557 is a pipe having a flow path cross section with a diameter of, for example, about 1 to 3 mm. As a result, the return pipe 557 spatially connects the inlet-side flow path 555 and the outlet-side flow path 556 with a cross section area smaller than that of each pipe.

[0075] The return pipe 557 has, for example, a circular cross-sectional shape, but may have other cross-sectional shapes such as an oval or a rectangle. The return pipe 557 has, for example, the same configuration as the return pipe 51 according to the first embodiment, but may also have the same configuration as the return pipe 53 according to the second embodiment.

[0076] 9, an oil trap 558 is formed below second flow path 555b in the direction of gravity (Z direction). As an example, oil trap 558 is a part of the conduit that forms second flow path 555b in the direction of gravity (Z direction). In other words, a part of second flow path 555b below the direction of gravity (Z direction), for example, a part below the connection part with first flow path 555a, functions as oil trap 538.

[0077] Here, a method for manufacturing the relay block 55 according to the embodiment will be described with reference to FIG.

[0078] As an example, the inlet-side connection portion 551 and the third flow path 555c (inlet-side flow path 555) are formed by cutting a non-through hole in the +X direction from one surface (YZ surface on the -X side) of the relay block 55. Note that the third flow path 555c (inlet-side flow path 555) may be formed by cutting a hole that penetrates from one surface (either YZ surface) of the relay block 55 to the other side in the X direction, and inserting an enclosing member such as a screw on the +X side.

[0079] As an example, the relay block side inlet 553 and the first flow path 555a (inlet side flow path 555) are formed by cutting a non-through hole in the -X direction from one surface (YZ surface on the +X side) of the relay block 55. Note that the first flow path 555a (inlet side flow path 555) may be formed by cutting a hole that penetrates from one surface (either YZ surface) of the relay block 55 to the other side in the X direction, and inserting a sealing member such as a screw on the -X side.

[0080] As an example, the second flow path 555b (inlet-side flow path 555) is formed by cutting a non-through hole in the +Z direction from the lower side (the XY plane on the -Z side) of the relay block 55 in the gravity direction, and inserting a sealing member such as a screw into the lower side (-Z side). The second flow path 555b (inlet-side flow path 555) may also be formed by cutting a non-through hole in the -Z direction from the upper side (the XY plane on the +Z side) of the relay block 55, and inserting a sealing member such as a screw into the upper side (the +Z side). The second flow path 555b (inlet-side flow path 555) may also be formed by cutting a hole that penetrates from one side (either XY plane) of the relay block 55 to the other side in the Z direction, and inserting a sealing member such as a screw into both ends in the gravity direction (Z direction).

[0081] As an example, the outlet side connection portion 552, the relay block side outlet 554 and the outlet side flow path 556 are formed by cutting a hole portion that penetrates from either side of one surface (YZ surface) of the relay block 55 to the other side in the X direction.

[0082] As an example, the return pipe 557 is formed by cutting a non-through hole in the Y direction from one face (either Z or X face) of the relay block 55 and inserting a sealing member such as a screw into the cut side. Note that the return pipe 557 may also be formed by cutting a hole that penetrates from one face (either Z or X face) of the relay block 55 to the other face in the Y direction and inserting a sealing member such as a screw into both ends in the cutting direction (Y direction).

[0083] Although the case where the relay block 55 is mainly formed by cutting has been exemplified, the present invention is not limited to this. The relay block 55 may also be formed by casting or using a 3D printer.

[0084] In this way, the relay block 55 can return oil from the inlet side to the outlet side by the return pipe 557 that bypasses the inlet side and outlet side of the cooling plate 4 inside the relay block 55. That is, according to the cooling system 1 to which the oil pool elimination device 5 of the present embodiment is applied, oil is sucked from the inlet side to the outlet side of the cooling plate 4 inside the relay block 55, thereby reducing the amount of compressor oil that flows into the flow path 43 via the inlet 41 of the cooling plate 4. That is, according to the cooling system 1 of the present embodiment, it is possible to prevent the compressor oil circulating together with the refrigerant from accumulating inside the cooling plate 4.

[0085] Furthermore, according to the cooling system 1 of this embodiment, when applying the oil pool elimination device 5, it is only necessary to prepare a relay block 55 that corresponds to the shape of the inlet and outlet of the cooling plate 4, and it is not necessary to process the cooling plate 4. This makes it possible to easily apply the oil pool elimination device 5 to an existing cooling plate 4.

[0086] According to at least one of the embodiments described above, it is possible to prevent the compressor oil circulating together with the refrigerant from accumulating inside the cooling plate 4.

[0087] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention described in the claims and their equivalents.

[0088] (Addendum) The above description of the embodiments discloses the following techniques. (1) a housing to which a heat dissipation target is thermally connected; an inlet connected to a high-pressure side pipe of an air conditioning system in which a refrigerant circulates, and into which a refrigerant is supplied from the high-pressure side pipe; a flow path formed inside the housing through which the refrigerant flowing in from the inlet flows; a cooling plate having an outlet connected to a low-pressure side pipe of the air conditioning system and discharging the refrigerant that has exchanged heat with the housing in the flow path into the low-pressure side pipe; a return pipe that spatially connects the inlet and the outlet of the cooling plate with a flow path cross section that is smaller than the flow path cross sections of the inlet and the outlet outside the housing of the cooling plate, Oil accumulation removal device. (2) At least a portion of the return pipe has a flow path cross section that becomes smaller from the inlet side toward the outlet side. The oil accumulation elimination device according to (1) above. (3) A flow path cross section of the flow path has a different shape from the inlet and the outlet. The oil accumulation elimination device according to (1) or (2) above. (4) a length of the inlet protruding from the housing is longer than a length of the outlet protruding from the housing; The return pipe spatially connects a hole provided in a portion of the inlet protruding from the housing and a hole provided in a portion of the outlet protruding from the housing. An oil pool elimination device according to any one of (1) to (3) above. (5) The return pipe is an oil trap provided below a hole provided on a lower side in the direction of gravity in a portion of the inlet protruding from the housing, and spatially connected to the hole of the inlet; a conduit that spatially connects the oil trap and a hole provided in a portion of the outlet that protrudes from the housing, The oil accumulation elimination device according to (4) above. (6) The oil trap is formed by a pipe extending downward from a hole provided below the inlet in the direction of gravity. The oil accumulation elimination device according to (5) above. (7) The conduit spatially connects a lower portion of the oil trap in the direction of gravity to the hole of the outflow outlet. The oil accumulation elimination device according to (5) or (6) above. (8) The pipe has a flow path cross section that becomes smaller from the oil trap side toward the outlet side. The oil accumulation elimination device according to (5) or (6) above. (9) an inlet-side flow path that spatially connects the high-pressure side pipe and the inlet; an outlet-side flow path that spatially connects the outlet and the low-pressure side pipe; a relay block having the return pipe formed therein, the return pipe spatially connecting a hole provided in the inlet-side flow path and a hole provided in the outlet-side flow path; An oil pool elimination device according to any one of (1) to (3) above. (10) The inlet side flow path is a first flow path extending from a connection portion with the high-pressure side pipe toward the inlet; a second flow path that is spatially connected to the first flow path and extends upward and downward in the direction of gravity from a connection portion with the first flow path; a third flow path that is spatially connected to an upper side of the second flow path in the direction of gravity and extends from a connection portion with the second flow path to a connection portion with the inlet, the return pipe spatially connects a hole provided below a connection portion of the second flow path with the first flow path in a gravitational direction and a hole of the outlet-side flow path. The oil accumulation elimination device according to (9) above. (11) In the second flow path of the inlet-side flow path, a portion below a connection portion with the first flow path in a gravity direction forms an oil trap. The oil accumulation elimination device according to (10) above. (12) a length of the inlet protruding from the housing is longer than a length of the outlet protruding from the housing; the third flow path of the inlet-side flow path is formed above the first flow path of the inlet-side flow path in a gravitational direction, The first flow path of the inlet-side flow path is formed above the outlet-side flow path in the direction of gravity. The oil accumulation elimination device according to (10) or (11) above. (13) a cooling plate having a housing to which a heat dissipation target is thermally connected, an inlet connected to a high-pressure side pipe of an air conditioning system in which a refrigerant circulates and through which the refrigerant is supplied from the high-pressure side pipe, a flow path formed inside the housing and through which the refrigerant flowing in from the inlet flows, and an outlet connected to a low-pressure side pipe of the air conditioning system and through which the refrigerant that has exchanged heat with the housing in the flow path is discharged to the low-pressure side pipe; and a return pipe that spatially connects the inlet and the outlet, outside the housing of the cooling plate, with a flow path cross section that is smaller than the flow path cross sections of the inlet and the outlet. an inlet-side flow path that spatially connects the high-pressure side pipe and the inlet; an outlet-side flow path that spatially connects the outlet and the low-pressure side pipe; and a relay block formed therein; the return pipe spatially connects a hole provided in the inlet-side flow path and a hole provided in the outlet-side flow path; Oil accumulation removal device. (14) An oil accumulation elimination device (cooling device) according to any one of (1) to (12) above; a power conversion unit that is configured by a plurality of electronic components including magnetic components, converts AC power supplied from an external single-phase or three-phase AC power source into DC power, and outputs the converted DC power; Coil device (power conversion device, on-board charger). (15) An oil accumulation elimination device (cooling device) according to any one of (1) to (12) above; a power conversion unit that is configured by a plurality of electronic components including magnetic components, converts input DC power into DC power of a predetermined voltage value, and outputs the converted DC power; Coil device (power conversion device, DC / DC converter). (16) The coil device according to (14) or (15), a battery that is charged using the DC power converted by the coil device; vehicle. [Explanation of symbols]

[0089] 1. Cooling system 2. Air conditioning system 21 Compressor 22 Condenser 23 Expansion valve 24 Evaporator 29 Piping 4 Cooling Plate 401 Case 41 Inlet 43 Flow path 45 Outlet 51 Return pipe 53 Return pipe 531 Oil Trap 533 Pipeline 55 Relay Block 551 Inlet side connection 552 Outlet side connection 553 Relay block side inlet 554 Relay block side outlet 555 Inlet flow path 556 Outflow channel 557 Return pipe 558 Oil Trap 6 On-board charger 61 PCB 63 Trans 65 electrolytic capacitors

Claims

1. a housing to which a heat dissipation target is thermally connected; an inlet connected to a high-pressure side pipe of an air conditioning system in which a refrigerant circulates, and into which a refrigerant is supplied from the high-pressure side pipe; a flow path formed inside the housing through which the refrigerant flowing in from the inlet flows; a cooling plate having an outlet connected to a low-pressure side pipe of the air conditioning system and discharging the refrigerant that has exchanged heat with the housing in the flow path into the low-pressure side pipe; a return pipe that spatially connects the inlet and the outlet of the cooling plate with a flow path cross section that is smaller than the flow path cross sections of the inlet and the outlet outside the housing of the cooling plate, Oil accumulation removal device.

2. At least a part of the return pipe has a flow path cross section that becomes smaller from the inlet side toward the outlet side. The oil pool elimination device according to claim 1.

3. A flow path cross section of the flow path has a different shape from the inlet and the outlet. The oil pool elimination device according to claim 1.

4. a length of the inlet protruding from the housing is longer than a length of the outlet protruding from the housing; The return pipe spatially connects a hole provided in a portion of the inlet protruding from the housing and a hole provided in a portion of the outlet protruding from the housing. The oil pool elimination device according to any one of claims 1 to 3.

5. The return pipe is an oil trap provided below a hole provided on a lower side in the direction of gravity in a portion of the inlet protruding from the housing, and spatially connected to the hole of the inlet; a conduit that spatially connects the oil trap and a hole provided in a portion of the outlet that protrudes from the housing, The oil pool elimination device according to claim 4.

6. The oil trap is formed by a pipe extending downward from a hole provided below the inlet in the direction of gravity. The oil pool elimination device according to claim 5.

7. The conduit spatially connects a lower portion of the oil trap in the direction of gravity to the hole of the outflow outlet. The oil pool elimination device according to claim 5.

8. The pipe has a flow path cross section that becomes smaller from the oil trap side toward the outlet side. The oil pool elimination device according to claim 5.

9. an inlet-side flow path that spatially connects the high-pressure side pipe and the inlet; an outlet-side flow path that spatially connects the outlet and the low-pressure side pipe; a relay block having the return pipe formed therein, the return pipe spatially connecting a hole provided in the inlet-side flow path and a hole provided in the outlet-side flow path; The oil pool elimination device according to any one of claims 1 to 3.

10. The inlet side flow path is a first flow path extending from a connection portion with the high-pressure side pipe toward the inlet; a second flow path that is spatially connected to the first flow path and extends upward and downward in the gravity direction from a connection portion with the first flow path; a third flow path that is spatially connected to an upper side of the second flow path in the gravity direction and extends from a connection portion with the second flow path to a connection portion with the inlet, the return pipe spatially connects a hole provided below a connection portion of the second flow path with the first flow path in a gravitational direction and a hole of the outlet-side flow path. The oil pool elimination device according to claim 9.

11. In the second flow path of the inlet-side flow path, a portion below a connection portion with the first flow path in a gravity direction forms an oil trap. The oil pool elimination device according to claim 10.

12. a length of the inlet protruding from the housing is longer than a length of the outlet protruding from the housing; the third flow path of the inlet-side flow path is formed above the first flow path of the inlet-side flow path in a gravitational direction, The first flow path of the inlet-side flow path is formed above the outlet-side flow path in the direction of gravity. The oil pool elimination device according to claim 10.

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