Oil cooler

Abstract

To provide an oil cooler capable of simplifying its construction while suppressing an increase in the size of a physical constitution.SOLUTION: An oil cooler for cooling oil with cooling water to lubricate a transaxle in the state of being mounted on a case storing the transaxle, includes an oil introduction port opening in a mounting face mounted to the case, an oil discharge port opening in the mounting face, a first opening for cooling water, opening in the mounting face, and a second opening for cooling water, opening in a site different from the mounting face. Heat exchange is performed between the oil flowing in an oil path linking the oil introduction port and the oil discharge port and the cooling water flowing in a water path linking the first opening and the second opening.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an oil cooler. [Background technology]

[0002] Patent Document 1 discloses an oil cooler that is attached to a case that contains a transaxle and oil and cools the oil with cooling water. This oil cooler has an oil inlet, an oil outlet, a cooling water inlet, and a cooling water outlet on the mounting surface that is attached to the case. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-052521 Summary of the Invention [Problem to be solved by the invention]

[0004] In the configuration described in Patent Document 1, the cooling water introduced from the case to the oil cooler is returned to the case after heat exchange, so the cooling water flows in the following order: case, oil cooler, case. In other words, the case needs to have a cooling water inlet (IN) and a cooling water outlet (OUT) that connect to a member other than the oil cooler as the inlet and outlet of the cooling water. In this case, the number of openings is 10 in total, four on the oil cooler side and six on the case side, which may lead to an increase in size and cost.

[0005] The present invention has been made in consideration of the above circumstances, and has an object to provide an oil cooler that can be simplified in structure and prevents an increase in size. [Means for solving the problem]

[0006] The present invention provides an oil cooler that cools oil that lubricates a transaxle with cooling water while attached to a case that houses the transaxle, and is equipped with an oil inlet opening into a mounting surface that is attached to the case, an oil outlet opening into the mounting surface, a first opening for cooling water that opens into the mounting surface, and a second opening for cooling water that opens to a location different from the mounting surface, and is characterized in that heat exchange is performed between the oil flowing through an oil passage connecting the oil inlet and the oil outlet and the cooling water flowing through a water passage connecting the first opening and the second opening.

[0007] According to this configuration, the number of openings on the surface attached to the case can be reduced to three, which allows the mounting surface to be made smaller and prevents the overall size from becoming larger. Also, in a unit structure in which the oil cooler is integrated with the case, the second opening functions as a cooling water inlet or outlet for the unit structure. In this case, the number of openings is four on the oil cooler side and four on the case side, for a total of eight, which allows the overall size to be made smaller and costs to be reduced.

[0008] The case may house a motor, a power conversion device that controls the motor, and the transaxle, the oil inlet being connected to an oil supply port provided in the case, the oil outlet being connected to an oil return port provided in the case, the first opening being connected to a cooling water connection port provided in the case, the oil being supplied to a motor chamber in the internal space of the case that houses the motor to cool the motor, and the cooling water being supplied to the power conversion device to cool the power conversion device.

[0009] According to this configuration, with the oil cooler attached to the mechanically and electrically integrated case, the oil in the transaxle and the motor can be cooled by the cooling water of the power conversion device.

[0010] In addition, the first opening may be connected to a cooling flow path that cools the power conversion device via a water passage formed inside the case, and the second opening may be connected to a member other than the case.

[0011] According to this configuration, the cooling passage of the power conversion device and the water passage of the oil cooler can be communicated with each other via the water passage formed inside the case. Effect of the Invention

[0012] In the present invention, the number of openings on the surface attached to the case can be reduced to three, making it possible to reduce the size of the attachment surface and prevent the overall size from increasing. Also, in a unit structure in which the oil cooler is integrated with the case, the second opening functions as a cooling water inlet or outlet for the unit structure. In this case, the number of openings is eight in total, four on the oil cooler side and four on the case side, making it possible to reduce the size of the overall size and costs. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic diagram showing a state in which an oil cooler is attached to a case having an integrated mechanical and electrical structure. [Diagram 2] FIG. 2 is a top view showing a schematic state in which the oil cooler is attached to a case having an integrated mechanical and electrical structure. [Diagram 3] FIG. 3 is a side view showing a schematic diagram of the oil cooler according to the embodiment attached to a case having an integrated mechanical and electrical structure. [Figure 4] FIG. 4 is a diagram showing the structure of the oil cooler. [Diagram 5] FIG. 5 is a diagram showing the flow of oil and the flow of coolant relative to the opening of the oil cooler. [Figure 6] FIG. 6 is a diagram for explaining the flow of oil and the flow of coolant when the oil cooler is attached to a case with an integrated mechanical and electrical structure. [Figure 7] FIG. 7 is a diagram for explaining the structure of the case. [Figure 8] FIG. 8 is a diagram showing a schematic structure of the comparative example. [Figure 9] FIG. 9 is a diagram showing the flow of oil and the flow of coolant in the structure of the comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an oil cooler according to an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiment described below.

[0015] 1 is a schematic diagram showing an oil cooler attached to a case having an integrated mechanical and electrical structure. The oil cooler 1 is applied to a drive unit 10 of an electric vehicle, and cools the oil in the drive unit 10 with cooling water.

[0016] 2 and 3, drive unit 10 includes a motor 11, a transaxle (T / A) 12, a case 13 that houses motor 11 and transaxle 12, and a power control unit (hereinafter referred to as PCU) 14. Drive unit 10 is a unit with an integrated mechanical and electrical structure in which PCU 14 is housed in case 13 that houses motor 11 and transaxle 12. Note that the "X direction" represents the front in the longitudinal direction of the electric vehicle, the "Y direction" represents the rightward direction in the width direction of the electric vehicle, and the "Z direction" represents the upward direction in the height direction of the electric vehicle.

[0017] Motor 11 is the power source of the electric vehicle. Transaxle 12 is a power transmission mechanism including gears and a rotating shaft, and transmits the power output from motor 11 to the wheels. PCU 14 is a power conversion device that controls motor 11, and includes an inverter and a converter. PCU 14 is electrically connected to motor 11, and converts battery power and supplies it to motor 11. This PCU 14 functions as a power control device that controls the power of motor 11. The PCU 14 is housed inside case 13.

[0018] The case 13 has a motor chamber that houses the motor 11, a gear chamber that houses the transaxle 12, and a PCU chamber that houses the PCU 14. The case 13 is formed to include a cover member 15 arranged to cover the upper part of the PCU chamber. The cover member 15 is attached to a case body of the case 13 by bolt fastening. Note that the cover member 15 is omitted in FIG. 2.

[0019] In this way, case 13 is a case with an electrically and mechanically integrated structure in which a case main body (transaxle case) that houses motor 11 and transaxle 12 and a case main body (PCU case) that houses PCU 14 are integrally molded. Therefore, PCU 14 disposed in case 13 can be expressed as PCU 14 housed in a transaxle case. Also, the walls of case 13 are common walls that serve as the walls of the PCU case and the walls of the transaxle case.

[0020] Additionally, oil common to the motor chamber and the gear chamber is accommodated inside case 13. Case 13 is formed to allow oil to flow between the gear chamber and the motor chamber. Therefore, the oil cools motor 11 inside the motor chamber, and the oil lubricates transaxle 12 inside the gear chamber. In other words, the oil introduced into oil cooler 1 is both a cooling oil that cools motor 11 and a lubricating oil that lubricates transaxle 12. In short, the oil is an insulating oil.

[0021] In addition, in the PCU room of the case 13, the PCU 14 is cooled by cooling water. The PCU 14 is provided with a cooling flow path (water passage) through which the cooling water flows, and the power module of the PCU 14 can be cooled by the cooling water flowing through the cooling flow path. That is, the PCU 14 is water-cooled and is connected to a cooling circuit in which the cooling water circulates. This cooling circuit is configured to include a water pump, a radiator, an oil cooler 1, and the PCU 14. Since the radiator is disposed at the front of the electric vehicle, the oil cooler 1 and the drive unit 10 are disposed at the front of the electric vehicle. In the cooling circuit, the cooling water pressure-fed by the water pump circulates. After cooling the PCU 14, the cooling water is pressure-fed to the radiator and dissipates heat in the radiator. Then, the cooling water cooled by the radiator is supplied to the PCU 14 to cool the PCU 14. This cooling water is, for example, LLC.

[0022] Oil cooler 1, attached to case 13, cools the oil in motor 11 and transaxle 12 with cooling water from PCU 14. Oil cooler 1 has oil passage 2 through which oil flows, and water passage 3 through which cooling water flows. In oil cooler 1, heat exchange occurs between the oil flowing through oil passage 2 and the cooling water flowing through water passage 3.

[0023] The oil cooler 1 also has a mounting surface 4 that is attached to the wall of the case 13. For example, the oil cooler 1 has a base plate portion that is bolted to the front wall of the case 13, and the surface of the base plate portion that faces the wall surface 13a of the front wall of the case 13 serves as the mounting surface 4. An opening of the oil passage 2 and an opening of the water passage 3 are open on the mounting surface 4.

[0024] As shown in FIG. 4, the oil cooler 1 includes 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 that opens into the mounting surface 4, and introduces oil into the oil cooler 1. This oil inlet 5 is disposed in a position facing the oil supply port 23 on the case 13 side in the X direction. In the Y direction, the oil inlet 5 is disposed in a different position from the cooling water inlet 7. In the Z direction, the oil inlet 5 does not have to be disposed in the same position as the cooling water inlet 7.

[0026] The oil discharge port 6 is an opening that opens into the mounting surface 4, and discharges oil outside the oil cooler 1. This oil discharge port 6 is disposed in a position facing the oil return port 24 on the case 13 side in the X direction. In the Z direction, the oil discharge port 6 is disposed in a different position from the oil inlet port 5. In the Y direction, the oil discharge port 6 does not have to be disposed in the same position as the oil inlet port 5.

[0027] The cooling water inlet 7 is an opening that opens into the mounting surface 4, and introduces cooling water into the oil cooler 1. The cooling water inlet 7 is a first opening for cooling water. The cooling water inlet 7 is disposed at a position facing the cooling water supply port 22 on the case 13 side in the X direction.

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

[0029] Inside the oil cooler 1, an oil passage 2 is formed to connect an oil inlet 5 and an oil outlet 6, and a water passage 3 is formed to connect a cooling water inlet 7 and a cooling water outlet 8. The oil passage 2 communicates between the oil inlet 5 and the oil outlet 6, and includes a heat exchange oil passage in its path where the oil exchanges heat with the cooling water in the water passage 3. The water passage 3 communicates between the cooling water inlet 7 and the cooling water outlet 8, and includes a heat exchange water passage in its path where the cooling water exchanges heat with the oil in the oil passage 2.

[0030] Regarding the exchange of oil between the oil cooler 1 and the case 13, the oil is introduced from the case 13 to the oil inlet 5 of the oil cooler 1 and flows through the oil passage 2 of the oil cooler 1, as shown by the dashed arrows in Figures 5 and 6. The oil that has flowed through the oil passage 2 in the oil cooler 1 is discharged from the oil outlet 6 that opens into the mounting surface 4 and returned to the case 13. Note that for ease of explanation, the oil cooler 1 is shown in a simplified hatched diagram in Figure 6.

[0031] Regarding the exchange of cooling water between the oil cooler 1 and the case 13, the cooling water is introduced from the case 13 to a cooling water inlet 7 of the oil cooler 1 and flows through the water passage 3 of the oil cooler 1, as shown by the solid arrows in Figures 5 and 6. The cooling water that has flowed through the water passage 3 in the oil cooler 1 is discharged from a cooling water outlet 8 that opens on the side opposite to the mounting surface 4. The cooling water outlet 8 is connected to a member separate from the case 13.

[0032] As shown in FIG. 7, the case 13 has a cooling water inlet 21, a cooling water supply port 22, an oil supply port 23, and an oil return port 24 as openings that open into the wall surface 13a of the front wall portion on which the oil cooler 1 is attached.

[0033] The cooling water inlet 21 is an opening that opens at a position on the wall surface 13a where the oil cooler 1 cannot be attached, and is connected to a member other than the oil cooler 1. The cooling water inlet 21 is connected to a member upstream of the case 13 in a cooling circuit through which the cooling water circulates. The cooling water inlet 21 introduces the cooling water into the case 13 after it has been cooled by the radiator.

[0034] 2, the cooling water inlet 21 communicates with the PCU 14 via a first case water passage 25 formed inside the case 13. The cooling water that flows from the cooling water inlet 21 into the first case water passage 25 is supplied to the PCU 14. The upstream side of the water passage of the PCU 14 communicates with the cooling water inlet 21 via the first case water passage 25. The downstream side of the water passage of the PCU 14 communicates with the cooling water supply port 22 via a second case water passage 26 formed inside the case 13.

[0035] Furthermore, a first case water passage 25 and a second case water passage 26 are disposed at positions overlapping with the position where the PCU 14 is disposed in the Y and Z directions. The first case water passage 25 and the second case 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 in the YZ plane, the first case water passage 25 and the second case water passage 26 extend along the X direction.

[0036] For example, the cooling water inlet 21 is disposed at a position overlapping with the PCU 14 in the Y direction and the Z direction, and the first case water passage 25 is formed to connect the cooling water inlet 21 and the PCU 14 via the shortest path. The cooling water supply port 22 is disposed at a position overlapping with the PCU 14 in the Y direction and the Z direction, and the second case water passage 26 is formed to connect the PCU 14 and the cooling water supply port 22 via the shortest path. In this way, the cooling water introduced from the cooling water inlet 21 flows through the first case water passage 25, the PCU 14, and the second case water passage 26 in this order.

[0037] The cooling water supply port 22 is an opening that opens at a position on the wall surface 13a where the oil cooler 1 is attached, and is a cooling water connection port that connects to the cooling water inlet 7 of the oil cooler 1. The cooling water supply port 22 and the cooling water inlet 7 are connected to each other, so that the second case water passage 26 and the water passage 3 of the oil cooler 1 communicate with each other. The cooling water supply port 22 and the cooling water inlet 7 are arranged to face each other and are directly connected to each other. Direct connection means that they are connected without using a member that forms a flow path, such as a hose. By directly connecting the cooling water inlet 7 to the cooling water supply port 22, the hoses connecting the oil cooler 1 and the case 13 and the hoses connecting the oil cooler 1 and the PCU 14 can be reduced, and the structure can be simplified. Therefore, it is possible for the cooling water supply port 22 and the cooling water inlet 7 to be connected in a state sealed by a sealant. In other words, the cooling water supply port 22 and the cooling water inlet 7 can be connected to each other via a sealant. 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] Oil supply port 23 is an opening that opens at a position on wall surface 13a where oil cooler 1 is attached, and is connected to oil inlet port 5 of oil cooler 1. By connecting oil supply port 23 and oil inlet port 5, an oil supply passage 27 formed inside case 13 and oil passage 2 of oil cooler 1 communicate with each other. Oil supply port 23 and oil inlet port 5 are disposed opposite each other and are directly connected to each other.

[0039] The oil return port 24 is an opening that opens into the wall surface 13a at a position where the oil cooler 1 is attached, and is connected to the oil discharge port 6 of the oil cooler 1. By connecting the oil return port 24 and the oil discharge port 6, a return oil passage 28 formed inside the case 13 and the oil passage 2 of the oil cooler 1 are communicated with each other. The oil return port 24 and the oil discharge port 6 are disposed opposite each other and are directly connected to each other.

[0040] 8 and 9, in the oil cooler 100 of the comparative example, a cooling water inlet 101, a cooling water outlet 102, an oil inlet 103, and an oil outlet 104 are opened on a surface attached to a case 110. The case 110 is provided with a cooling water inlet 111, a cooling water supply port 112, a cooling water return port 113, a cooling water outlet 114, an oil supply port 115, and an oil return port 116. The cooling water inlet 111 and the cooling water outlet 114 are opened at a position where the oil cooler 100 is not attached. The cooling water supply port 112, the cooling water return port 113, the oil supply port 115, and the oil return port 116 are opened at a position where the oil cooler 100 is attached. 9, the cooling water flows through a route of cooling water inlet 111, case 110, cooling water supply port 112, cooling water inlet 101, oil cooler 100, cooling water outlet 102, cooling water return port 113, case 110, and cooling water outlet 114. In the structure of the comparative example, the number of openings is ten in total, four in oil cooler 100 and six in case 110. In this way, the oil cooler 1 of the embodiment can reduce the number of openings by two compared to the structure of the comparative example.

[0041] In addition, in the structure of the comparative example, a total of two water channel pipes, one on the inlet side (IN) and one on the outlet side (OUT), which form a flow path for the cooling water, must be arranged on the wall surface of the front wall of the case 110. Therefore, when the electric vehicle becomes smaller and the drive unit becomes smaller, the mounting space for each component is also reduced, so there is a high possibility that the oil cooler 100 and the water channel pipes will interfere with each other on the wall of the case 110. In particular, when the radiator is arranged on the front of the electric vehicle, the water channel and the oil cooler are often arranged on the front of the electric vehicle, which poses mounting issues for any electric vehicle. In contrast, in the oil cooler 1 of the embodiment, the path through which the cooling water flows is in the order of the water channel pipe, the case 13, the PCU 14, the case 13, the oil cooler 1, and the water channel pipe, so that interference between the oil cooler 1 and the water channel pipe on the wall of the case 13 can be avoided.

[0042] As described above, according to the embodiment, the number of openings can be set to a total of eight, four in the oil cooler 1 and four in the case 13. This makes it possible to prevent the overall size from increasing and to reduce costs. Furthermore, since the number of openings on the mounting surface 4 can be set to three, the mounting surface 4 can be made smaller and the overall size can be prevented from increasing.

[0043] Furthermore, according to the embodiment, the PCU 14 can be arranged immediately after the oil cooler 1 in the X direction, so that the water passage between the oil cooler 1 and the PCU 14 can be connected via the shortest route. This allows the volume to be reduced, and therefore the overall size to be made more compact.

[0044] The electric vehicle to which the oil cooler 1 can be applied may be any of an electric vehicle (BEV), a hybrid vehicle (HEV), a plug-in hybrid vehicle (PHEV), and a fuel cell vehicle (FCEV).

[0045] In addition, the direction in which the cooling water flows and the direction in which the oil flows are not limited to the directions exemplified in FIG. 5 and FIG. 6. For example, the cooling water may 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 through the radiator, the oil cooler 1, the case 13, the PCU 14, and the case 13 in this order. In short, the oil cooler 1 may have a structure having a first opening for the cooling water that opens on the mounting surface 4 and a second opening for the cooling water that opens on a position different from the mounting surface 4, and either the first opening or the second opening may be the inlet. Similarly, the oil may be introduced from the oil outlet 6 of the oil cooler 1 and discharged from the oil inlet 5.

[0046] In addition, the shape and connection destination of the supply oil passage 27 and the return oil passage 28 formed in the case 13 are not particularly limited. For example, the supply oil passage 27 is connected to a catch tank formed in the gear chamber. Oil scooped up by the gears in the gear chamber of the case 13 is accumulated in the catch tank. The oil accumulated in the catch tank flows into the supply oil passage 27. The return oil passage 28 is connected to a cooling pipe in the motor chamber of the case 13. The cooling pipe supplies (sprays) oil from above the motor toward the stator. The oil sprayed from the cooling pipe to the stator (for example, the coil end) of the motor is oil that has been cooled by the oil cooler 1, so that the cooling performance of the motor is improved. The oil flowing through the supply oil passage 27 and the return oil passage 28 of the case 13 may be pumped by an oil pump. It is possible to configure the oil to be pumped by the oil pump from the catch tank to the supply oil passage 27, the oil passage 2 of the oil cooler 1, the return oil passage 28, and the cooling pipe. When pumping oil from the oil pump, it is also possible to configure the oil pump to suck in oil stored in an oil reservoir formed in the lower part of the gear chamber and discharge it into the oil supply passage, rather than in a catch tank.

[0047] Furthermore, the case 13 is not limited to a structure in which a portion that functions as a transaxle case and a portion that functions as a PCU case are integrally molded. In other words, the case body of the case 13 may have a structure formed by combining a plurality of members. Therefore, the case body that functions as a transaxle case may also have a structure in which a member that forms a motor chamber and a member that forms a gear chamber are integrated together. In short, the flow paths formed inside the case 13 may be formed so that the water path through which the coolant flows and the oil path through which the oil flows are communicated via a plurality of members.

[0048] Also, the structure in which the oil cooler 1 is attached to the front wall of the case 13 has been described, but the present invention is not limited to this. The oil cooler 1 may be attached to the rear wall of the case 13. In other words, the oil cooler 1 does not have to be attached to the same wall as the cooling water inlet 21 of the case 13.

[0049] Furthermore, the cooling water inlet 21 of the case 13 is not limited to being provided in the front wall of the case 13. For example, the cooling water inlet 21 may be provided in a side wall or a rear wall of the case 13. In other words, the cooling water inlet 21 does not necessarily have to be provided in the wall on which the oil cooler 1 is attached.

[0050] Also, although the case 13 has been described as having an electrically and mechanically integrated structure, the present invention is not limited to this. The case 13 may simply house at least one of the motor 11 and the transaxle 12, and may not necessarily house the PCU 14. In other words, the oil cooler 1 is not limited to the electrically and mechanically integrated drive unit 10, and may be applied to other drive units. Therefore, the cooling water may simply be cooling water that cools the oil in the case 13, and may not necessarily be cooling water for cooling the PCU 14. [Explanation of symbols]

[0051] 1 Oil cooler 2 Oil road 3. Waterways 4 Mounting surface 5 Oil inlet 6 Oil outlet 7 Cooling water inlet 8 Cooling water outlet 11 Motor 12 Transaxle 13 Cases 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 that is attached to a case that houses a transaxle and cools oil that lubricates the transaxle with cooling water, an oil inlet opening on a mounting surface attached to the case; an oil drain opening that opens to the mounting surface; a first opening for cooling water that opens to the mounting surface; a second opening for cooling water that opens to a position different from the mounting surface; Equipped with heat exchange is performed between the oil flowing through an oil passage connecting the oil inlet and the oil outlet and the cooling water flowing through a water passage connecting the first opening and the second opening; The case accommodates a motor, a PCU which is a power conversion device that controls the motor, and the transaxle, The oil inlet is connected to an oil supply port provided in the case, The oil discharge port is connected to an oil return port provided in the case, The oil is supplied to a motor chamber that houses the motor in the internal space of the case to cool the motor, The PCU is provided with a cooling flow path through which the cooling water flows, The cooling flow passage communicates with the first opening via a case water passage formed inside the case, the first opening is connected to a cooling water connection port provided in the case, and communicates with the cooling flow passage via the cooling water connection port and the case water passage; The cooling water is supplied to the PCU to cool the PCU, The second opening is open on the opposite side to the mounting surface and is connected to a member other than the case. The oil cooler is characterized by:

2. The case waterway is formed to connect the PCU and the first opening via the shortest path.

2. The oil cooler according to claim 1 .

3. The motor is a power source for an electric vehicle, The case water channel and the first opening are disposed at a position overlapping with a position where the PCU is disposed in a vehicle width direction and a height direction of the electric vehicle.

3. The oil cooler according to claim 2.

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