Oil cooler

Abstract

The present application can simplify the structure and inhibit the increase in size. An oil cooler cools oil for lubricating a variable drive axle by using cooling water in a state where the oil cooler is mounted on a housing that houses the variable drive axle. The oil cooler includes an oil introduction port that is opened in a mounting surface of the housing, an oil discharge port that is opened in the mounting surface, a first opening for the cooling water that is opened in the mounting surface, and a second opening for the cooling water that is opened in a portion different from the mounting surface. Heat exchange is performed between the oil flowing in an oil passage that connects the oil introduction port and the oil discharge port and the cooling water flowing in a water passage that connects the first opening and the second opening.

Description

Technical Field

[0001] This invention relates to oil coolers. Background Technology

[0002] Patent Document 1 discloses an oil cooler that cools the oil using cooling water when mounted on a housing that houses a transmission drive axle and oil. The oil cooler has an oil inlet, an oil outlet, a cooling water inlet, and a cooling water outlet opening onto a mounting surface that connects to the housing. Existing technical documents Patent documents

[0003] Patent Document 1: Japanese Patent Application Publication No. 2021-052521 Summary of the Invention The technical problem that the invention aims to solve

[0004] In the configuration described in Patent Document 1, since the cooling water introduced from the housing to the oil cooler returns to the housing after heat exchange, the cooling water flow path is in the order of housing, oil cooler, housing. That is, the housing needs to have a cooling water inlet (IN) and a cooling water outlet (OUT) connected to a component different from the oil cooler as the cooling water inlet and outlet. In this case, the number of openings is 4 on the oil cooler side and 6 on the housing side, totaling 10, which may lead to a larger size and increased cost.

[0005] The present invention was made in view of the above circumstances, and its object is to provide an oil cooler that can simplify the structure and reduce the size of the unit. Means for solving technical problems

[0006] The oil cooler of the present invention, when mounted on a housing housing a transmission drive axle, uses cooling water to cool the oil that lubricates the transmission drive axle. The oil cooler includes: an oil inlet opening on a mounting surface that is mounted to the housing; an oil outlet opening on the mounting surface; a first opening for cooling water opening on the mounting surface; and a second opening for cooling water opening at a location different from the mounting surface. Heat exchange occurs between the oil flowing in an oil passage connecting the oil inlet and the oil outlet, and the cooling water flowing in a water passage connecting the first opening and the second opening.

[0007] According to this configuration, since the number of openings on the surface to which the housing is mounted is three, the mounting surface area can be reduced, thus preventing the size from becoming too large. Furthermore, in a unit structure where the oil cooler and housing are integrated, the second opening functions as either a cooling water inlet or outlet within the unit structure. In this case, the number of openings is four on the oil cooler side and four on the housing side, totaling eight, which allows for a smaller size and cost reduction.

[0008] Alternatively, the housing may house the motor, the power conversion device that controls the motor, and the transmission drive axle. The oil inlet is connected to the oil supply port provided in the housing, the oil outlet is connected to the oil return port provided in the housing, and the first opening is connected to the cooling water connection port provided in the housing. The oil is supplied to the motor chamber housing the motor in the internal space of the housing to cool the motor, and the cooling water is supplied to the power conversion device to cool the power conversion device.

[0009] According to this configuration, with an oil cooler installed on the housing of the electromechanical integrated structure, the oil of the transmission drive axle and the motor can be cooled by the cooling water of the power conversion device.

[0010] Alternatively, the first opening may be connected to a cooling flow path for cooling the power conversion device via a water passage formed inside the housing, and the second opening may be connected to a component different from the housing.

[0011] According to this configuration, the cooling flow path of the power conversion device can be connected to the water flow path of the oil cooler via a water channel formed inside the casing. Invention Effects

[0012] In this invention, since the number of openings on the surface to which the housing is mounted is three, the mounting surface area can be reduced, thus preventing the size from becoming too large. Furthermore, in the unit structure where the oil cooler and housing are integrated, the second opening functions as either a cooling water inlet or outlet within the unit structure. In this case, the number of openings is four on the oil cooler side and four on the housing side, totaling eight, which allows for a smaller size and cost reduction. Attached Figure Description

[0013] Figure 1 This diagram schematically shows the oil cooler mounted on the housing of an electromechanical integrated structure. Figure 2 This is a top view schematically showing the oil cooler mounted on the housing of an electromechanical integrated structure. Figure 3This is a side view schematically showing the state in which the oil cooler in the embodiment is mounted on the housing of the electromechanical integrated structure. Figure 4 This is a diagram showing the structure of an oil cooler. Figure 5 This is a diagram showing the flow of oil and coolant relative to the opening of the oil cooler. Figure 6 This diagram illustrates the flow of oil and coolant when the oil cooler is mounted on the housing of an electromechanical integrated structure. Figure 7 It is a diagram used to illustrate the structure of the shell. Figure 8 This is a diagram schematically illustrating the structure of the comparative example. Figure 9 This is a diagram showing the flow of oil and coolant in the structure of the comparative example. Detailed Implementation

[0014] The oil cooler according to an embodiment of the present invention will now be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described below.

[0015] Figure 1 This diagram schematically shows the state in which the oil cooler is mounted on the housing of the electromechanical integrated structure. The oil cooler 1 is suitable for the drive unit 10 of an electric vehicle and uses cooling water to cool the oil of the drive unit 10.

[0016] like Figure 2 and Figure 3 As shown, the drive unit 10 includes an electric motor 11, a transmission / drive axle (T / A) 12, a housing 13 housing the electric motor 11 and the transmission / drive axle 12, and a power control unit (hereinafter referred to as PCU) 14. This drive unit 10 is an electromechanical integrated unit that houses the PCU 14 within the housing 13 housing the electric motor 11 and the transmission / drive axle 12. Furthermore, "X direction" refers to the front in the longitudinal direction of the electric vehicle, "Y direction" refers to the right side in the width direction of the electric vehicle, and "Z direction" refers to the upper part in the height direction of the electric vehicle.

[0017] The electric motor 11 is the power source of the electric vehicle. The transmission drive axle 12 is a power transmission mechanism including gears and rotating shafts, which transmits the power output from the electric motor 11 to the wheels. The power conversion unit (PCU) 14 is a power conversion device that controls the electric motor 11, and is composed of an inverter and a converter. The PCU 14 is electrically connected to the electric motor 11, converts the power from the battery, and supplies it to the electric motor 11. The PCU 14 functions as a power control device that controls the power of the electric motor 11. Furthermore, the PCU 14 is housed inside the housing 13.

[0018] The housing 13 has a motor chamber for housing the electric motor 11, a gear chamber for housing the transmission drive axle 12, and a PCU chamber for housing the PCU 14. The housing 13 is formed including a cover member 15, which is configured to block the upper part of the PCU chamber. The cover member 15 is bolted to the main body of the housing 13. Furthermore, in... Figure 2 The cover component 15 is omitted.

[0019] Thus, housing 13 is an electromechanical integrated structure formed by the housing body (transmission drive axle housing) that houses the motor 11 and the transmission drive axle 12, and the housing body (PCU housing) that houses the PCU 14. Therefore, the PCU 14 disposed within housing 13 can be expressed as PCU 14 housed within the transmission drive axle housing. Furthermore, the wall portion of housing 13 becomes a wall portion that is shared between the PCU housing wall portion and the transmission drive axle housing wall portion.

[0020] Furthermore, inside the housing 13, the motor chamber and gear chamber contain a common oil. The housing 13 is configured to allow oil to flow between the gear chamber and the motor chamber. Therefore, the oil in the motor chamber cools the motor 11, and the oil in the gear chamber lubricates the transmission drive axle 12. In other words, the oil introduced into the oil cooler 1 is both cooling oil for the motor 11 and lubricating oil for the transmission drive axle 12. In short, the oil is an insulating oil.

[0021] Additionally, within the PCU chamber of housing 13, PCU 14 is cooled by cooling water. A cooling flow path (water path) for cooling water is provided in PCU 14, allowing cooling water to flow within this path, thus cooling the power modules of PCU 14. In other words, PCU 14 is water-cooled and connected to a cooling circuit that circulates cooling water. This cooling circuit comprises a water pump, a radiator, an oil cooler 1, and PCU 14. Since the radiator is located at the front of the electric vehicle, the oil cooler 1 and drive unit 10 are also located at the front of the electric vehicle. Within the cooling circuit, cooling water pumped by the water pump circulates. The cooling water that has cooled PCU 14 is pumped to the radiator for heat dissipation. Then, the cooling water cooled by the radiator is supplied to PCU 14 to further cool it. This cooling water is, for example, LLC.

[0022] When installed in the housing 13, the oil cooler 1 uses the cooling water from the PCU 14 to cool the oil in the motor 11 and the transmission drive axle 12. The oil cooler 1 has an oil passage 2 for supplying oil and a water passage 3 for supplying cooling water. In the oil cooler 1, heat exchange occurs between the oil flowing in the oil passage 2 and the cooling water flowing in the water passage 3.

[0023] In addition, the oil cooler 1 has a mounting surface 4 for mounting onto the wall of the housing 13. For example, the oil cooler 1 has a base plate portion that is bolted to the front wall of the housing 13, and the surface of this base plate portion that faces the wall surface 13a of the front wall of the housing 13 becomes the mounting surface 4. The openings of the oil passage 2 and the water passage 3 are opened on the mounting surface 4.

[0024] like Figure 4 As shown, the oil cooler 1 has an oil inlet 5, an oil outlet 6, a cooling water inlet 7, and a cooling water outlet 8.

[0025] The oil inlet 5 is an opening on the mounting surface 4 that allows oil to be introduced into the oil cooler 1. This oil inlet 5 is positioned opposite the oil supply port 23 on the housing 13 side in the X direction. In the Y direction, the oil inlet 5 is positioned differently from the cooling water inlet 7. In the Z direction, the oil inlet 5 may not be positioned at the same location as the cooling water inlet 7.

[0026] The oil outlet 6 is an opening on the mounting surface 4 that discharges oil to the outside of the oil cooler 1. This oil outlet 6 is positioned opposite the oil return port 24 on the housing 13 side in the X direction. In the Z direction, the oil outlet 6 is positioned differently from the oil inlet 5. In the Y direction, the oil outlet 6 may not be positioned at the same location as the oil inlet 5.

[0027] The cooling water inlet 7 is an opening on the mounting surface 4 that allows cooling water to be introduced into the oil cooler 1. This cooling water inlet 7 is the first opening for cooling water. It is positioned opposite the cooling water supply port 22 on the housing 13 side in the X direction.

[0028] The cooling water outlet 8 is an opening located at a position different from the mounting surface 4, through which cooling water is discharged to the outside of the oil cooler 1. For example, it can be configured such that the cooling water outlet 8 opens on the side opposite to the mounting surface 4. This cooling water outlet 8 is a second opening for cooling water.

[0029] Inside the oil cooler 1, an oil passage 2 is formed by connecting the oil inlet 5 and the oil outlet 6, and a water passage 3 is formed by connecting the cooling water inlet 7 and the cooling water outlet 8. The oil passage 2 connects the oil inlet 5 and the oil outlet 6, and its path includes a heat exchange oil passage for heat exchange between the oil and the cooling water in the water passage 3. The water passage 3 connects the cooling water inlet 7 and the cooling water outlet 8, and its path includes a heat exchange water passage for heat exchange between the cooling water and the oil in the oil passage 2.

[0030] Regarding the oil exchange between the oil cooler 1 and the housing 13, such as Figure 5 and Figure 6As indicated by the dashed arrow, oil is introduced from the housing 13 into the oil inlet 5 of the oil cooler 1, and flows through the oil passage 2 of the oil cooler 1. After flowing through the oil passage 2 within the oil cooler 1, the oil is discharged from the oil outlet 6, which opens on the mounting surface 4, and returns to the housing 13. Additionally, in Figure 6 In the diagram, for ease of explanation, the oil cooler 1 is shown in a simplified diagram with shading lines.

[0031] Regarding the exchange of cooling water between the oil cooler 1 and the casing 13, such as Figure 5 and Figure 6 As indicated by the solid arrow, cooling water is introduced from the housing 13 into the cooling water inlet 7 of the oil cooler 1, and flows through the water passage 3 of the oil cooler 1. After flowing through the water passage 3 within the oil cooler 1, the cooling water is discharged from the cooling water outlet 8, which opens on the side opposite to the mounting surface 4. The cooling water outlet 8 is connected to a component different from the housing 13.

[0032] like Figure 7 As shown, the housing 13 has a cooling water inlet 21, a cooling water supply inlet 22, an oil supply inlet 23, and an oil return inlet 24 as openings on the wall surface 13a of the front wall where the oil cooler 1 is installed.

[0033] The cooling water inlet 21 is an opening on the wall surface 13a where the oil cooler 1 is not installed, and it is connected to a component different from the oil cooler 1. The cooling water inlet 21 is connected to a component upstream of the housing 13 in the cooling circuit for cooling water circulation. The cooling water inlet 21 introduces cooling water cooled by the radiator into the housing 13.

[0034] In addition, such as Figure 2 As shown, the cooling water inlet 21 is connected to the PCU 14 via a first housing water passage 25 formed inside the housing 13. Cooling water flowing from the cooling water inlet 21 into the first housing water passage 25 is supplied to the PCU 14. The upstream side of the water passage of the PCU 14 is connected to the cooling water inlet 21 via the first housing water passage 25. The downstream side of the water passage of the PCU 14 is connected to the cooling water supply port 22 via a second housing water passage 26 formed inside the housing 13.

[0035] Furthermore, in the Y and Z directions, at positions overlapping with the location where the PCU 14 is arranged, a first housing water passage 25 and a second housing water passage 26 are arranged. The first housing water passage 25 and the second housing water passage 26 extend in a direction perpendicular to the mounting surface 4 of the oil cooler 1. When the mounting surface 4 is a plane extending on the YZ plane, the first housing water passage 25 and the second housing water passage 26 extend along the X direction.

[0036] For example, the cooling water inlet 21 is positioned overlapping the PCU 14 in both the Y and Z directions, and the first housing water passage 25 is formed to connect the cooling water inlet 21 and the PCU 14 using the shortest path. Similarly, the cooling water supply inlet 22 is positioned overlapping the PCU 14 in both the Y and Z directions, and the second housing water passage 26 is formed to connect the PCU 14 and the cooling water supply inlet 22 using the shortest path. Thus, cooling water introduced from the cooling water inlet 21 flows sequentially through the first housing water passage 25, the PCU 14, and the second housing water passage 26.

[0037] The cooling water supply port 22 is an opening on the wall surface 13a where the oil cooler 1 is installed, and it is a cooling water connection port connected to the cooling water inlet 7 of the oil cooler 1. By connecting the cooling water supply port 22 to the cooling water inlet 7, the second housing water passage 26 is connected to the water passage 3 of the oil cooler 1. The cooling water supply port 22 and the cooling water inlet 7 are arranged opposite each other and directly connected. Direct connection means that they are connected without forming a flow path through components such as hoses. By directly connecting the cooling water inlet 7 to the cooling water supply port 22, the number of hoses connecting the oil cooler 1 to the housing 13 and the oil cooler 1 to the PCU 14 can be reduced, simplifying the structure. Therefore, the cooling water supply port 22 and the cooling water inlet 7 can be connected in a sealed state. That is, the cooling water supply port 22 and the cooling water inlet 7 can be connected via a seal. This is not limited to the cooling water supply port 22, but also applies to the oil supply port 23 and the oil return port 24.

[0038] The oil supply port 23 is an opening on the wall surface 13a at the location where the oil cooler 1 is installed, and it is connected to the oil inlet 5 of the oil cooler 1. By connecting the oil supply port 23 to the oil inlet 5, the oil supply passage 27 formed inside the housing 13 is connected to the oil passage 2 of the oil cooler 1. The oil supply port 23 and the oil inlet 5 are arranged opposite each other and are directly connected.

[0039] The oil return port 24 is an opening on the wall surface 13a where the oil cooler 1 is installed, and it connects to the oil drain outlet 6 of the oil cooler 1. By connecting the oil return port 24 to the oil drain outlet 6, a return oil passage 28 is formed inside the housing 13, which communicates with the oil passage 2 of the oil cooler 1. The oil return port 24 and the oil drain outlet 6 are configured opposite each other and are directly connected.

[0040] like Figure 8 and Figure 9As shown, in the comparative example oil cooler 100, the cooling water inlet 101, cooling water outlet 102, oil inlet 103, and oil outlet 104 are open on the surface to which the housing 110 is mounted. The housing 110 includes a cooling water inlet 111, a cooling water supply inlet 112, a cooling water return inlet 113, a cooling water outlet 114, an oil supply inlet 115, and an oil return inlet 116. The cooling water inlet 111 and cooling water outlet 114 are open in a position where the oil cooler 100 is not installed. The cooling water supply inlet 112, cooling water return inlet 113, oil supply inlet 115, and oil return inlet 116 are open in a position where the oil cooler 100 is installed. Furthermore, as... Figure 9 As indicated by the solid arrows, cooling water flows through the path of cooling water inlet 111, housing 110, cooling water supply inlet 112, cooling water inlet 101, oil cooler 100, cooling water outlet 102, cooling water return inlet 113, housing 110, and cooling water outlet 114. In the comparative example structure, the number of openings is 4 on the oil cooler 100 and 6 on the housing 110, totaling 10. Thus, the oil cooler 1 of the embodiment can reduce the number of openings by 2 compared to the structure of the comparative example.

[0041] Furthermore, in the comparative example structure, two water pipes, one on the inlet side (IN) and one on the outlet side (OUT), forming a flow path for cooling water, need to be installed on the front wall of the housing 110. Therefore, since the space for mounting components is reduced as electric vehicles and drive units are miniaturized, the oil cooler 100 and the water pipes are likely to interfere with each other on the wall of the housing 110. In particular, when the radiator is positioned at the front of the electric vehicle, both the water pipes and the oil cooler are often located at the front, so there will be technical problems with their installation regardless of the type of electric vehicle. In contrast, in the oil cooler 1 of the embodiment, the cooling water flow path is water pipes, housing 13, PCU 14, housing 13, oil cooler 1, and water pipes in that order, thus avoiding interference between the oil cooler 1 and the water pipes on the wall of the housing 13.

[0042] As explained above, according to the embodiment, the number of openings can be 4 on the oil cooler 1 and 4 on the housing 13, for a total of 8. This helps to prevent the size of the device from becoming too large and reduces costs. Furthermore, since the number of openings on the mounting surface 4 can be 3, the mounting surface 4 can be reduced in size, further preventing the size of the device from becoming too large.

[0043] Furthermore, according to the embodiment, regarding the X-direction configuration, since the PCU 14 can be configured immediately following the oil cooler 1, the water passage between the oil cooler 1 and the PCU 14 can be connected using the shortest path. This reduces the volume, thus enabling miniaturization of the overall size.

[0044] In addition, the electric vehicle that can use the oil cooler 1 can be any of the following: battery electric vehicle (BEV), hybrid electric vehicle (HEV), plug-in hybrid electric vehicle (PHEV), or fuel cell electric vehicle (FCEV).

[0045] In addition, the direction of cooling water flow and the direction of oil flow are not limited to Figure 5 and Figure 6 The directions illustrated are as follows. For example, cooling water can be introduced from the cooling water outlet 8 of the oil cooler 1 and discharged from the cooling water inlet 7. In this case, the cooling water flows sequentially through the radiator, oil cooler 1, housing 13, PCU 14, and housing 13. In short, the oil cooler 1 can be any structure having a first opening for cooling water on the mounting surface 4 and a second opening for cooling water at a location different from the mounting surface 4; either the first opening or the second opening can be the inlet. Similarly, oil can be introduced from the oil outlet 6 of the oil cooler 1 and discharged from the oil inlet 5.

[0046] Furthermore, the shape and connection of the oil supply passage 27 and return passage 28 formed in the housing 13 are not particularly limited. For example, the oil supply passage 27 communicates with an oil collection tank formed in the gear chamber. Oil scraped up by the gears in the gear chamber of the housing 13 accumulates in the oil collection tank. The oil accumulated in the oil collection tank flows into the oil supply passage 27. The return passage 28 communicates with a cooling pipe in the motor chamber of the housing 13. The cooling pipe supplies (sprays) oil from above the motor toward the stator. The oil sprayed from the cooling pipe onto the stator (e.g., the coil end) of the motor is oil that has been cooled in the oil cooler 1, thus improving the cooling performance of the motor. The oil flowing in the oil supply passage 27 and return passage 28 of the housing 13 can also be pumped by an oil pump. It can be configured such that oil is pumped from the oil collection tank to the oil supply passage 27, the oil passage 2 of the oil cooler 1, the return passage 28, and the cooling pipe by an oil pump. When pumping oil from the oil pump, it can also be configured such that the oil stored in the oil storage section formed in the lower part of the gear chamber, rather than the oil collection tank, is drawn in by the oil pump and discharged to the oil supply line.

[0047] Furthermore, the housing 13 is not limited to a structure in which the part functioning as the transmission drive axle housing and the part functioning as the PCU housing are integrally formed. That is, the main body of the housing 13 can be a structure formed by combining multiple components. Therefore, the main body of the housing that functions as the transmission drive axle housing can also be a structure in which the component forming the motor chamber and the component forming the gear chamber are integrally formed. In short, regarding the water passage for coolant flow and the oil passage for oil flow, the flow paths formed inside the housing 13 can be formed in a manner that connects multiple components.

[0048] Furthermore, although the structure of the oil cooler 1 mounted on the front wall of the housing 13 has been described, it is not limited thereto. The oil cooler 1 may also be mounted on the rear wall of the housing 13. That is to say, the oil cooler 1 may not be mounted on the same wall of the housing 13 as the cooling water inlet 21.

[0049] Furthermore, the cooling water inlet 21 of the housing 13 is not limited to a structure where it is located on the front wall of the housing 13. For example, the cooling water inlet 21 may also be located on the side wall or rear wall of the housing 13. In short, the cooling water inlet 21 is not necessarily located on the wall where the oil cooler 1 is installed.

[0050] Furthermore, while the case where housing 13 is an electromechanical integrated structure has been described, it is not limited to this. Housing 13 may be any housing that houses at least one of the motor 11 and the transmission drive axle 12, and may not necessarily house the PCU 14. In short, the oil cooler 1 is not limited to the electromechanical integrated drive unit 10, and may be applicable to other drive units. Therefore, the cooling water may be any cooling water used to cool the oil inside housing 13, and may not necessarily be cooling water used to cool the PCU 14. [Explanation of reference numerals in the attached figures]

[0051] 1. Oil cooler 2. Oil circuit 3 waterways 4 mounting surfaces 5. Oil inlet 6. Oil discharge outlet 7 Cooling water inlet 8 Cooling water outlet 11 Electric motor 12 Transmission drive axle 13 Housing 14 Power control unit (PCU) 21 Cooling water inlet 22 Cooling water supply port 23 Oil supply port 24 Oil return port

Claims

1. An oil cooler, which, when mounted on a housing housing a transmission drive axle, cools the oil lubricating the transmission drive axle using cooling water, characterized in that, The oil cooler includes: An oil inlet is provided on the mounting surface that leads to the housing. An oil drain port is opened on the mounting surface; A first opening for cooling water is provided on the mounting surface. as well as A second opening for cooling water, located at a different location from the mounting surface. Heat exchange occurs between the oil flowing in the oil passage connecting the oil inlet and the oil outlet, and the cooling water flowing in the water passage connecting the first opening and the second opening. The housing houses the motor, the power conversion device that controls the motor, and the variable speed drive axle. The oil inlet is connected to the oil supply port located on the housing. The oil outlet is connected to the oil return port located on the housing. The oil is supplied to the motor chamber inside the housing to cool the motor. The cooling water is supplied to the power conversion device to cool it. The first opening overlaps with the power conversion device in a direction perpendicular to the mounting surface. The first opening is connected to the power conversion device via a waterway formed inside the housing via the shortest path.

2. The oil cooler according to claim 1, characterized in that, The second opening is connected to a component different from the housing.

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