Electric vehicles

Abstract

To provide an electric vehicle which enables improvement of cooling performance to an electric motor and a power control unit.SOLUTION: A cooling oil passage in which an oil discharged from an oil pump is jetted to an electric motor to cool the electric motor is disposed between the electric motor and a power control unit disposed adjacent to the electric motor in a vertically upward direction. The structure allows the oil jetted from the cooling oil passage to cool the electric motor and the power control unit and inhibit heat generation of the electric motor and the power control unit. Therefore, cooling performance of the electric motor and the power control unit can be improved.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to an electric vehicle provided with a cooling oil passage that injects oil onto an electric motor for cooling the electric motor. Background Art

[0002] Electric vehicles are well known that comprise: an electric motor; a power transmission device to which the electric motor is coupled so as to enable power transmission; a driving battery; a power control device that controls electric power transferred between the battery and the electric motor; and a case that houses, as an electromechanical integrated unit, a driving device including the electric motor and the power transmission device, and the power control device. For example, the electromechanical integrated device described in Patent Document 1 is one such example. This Patent Document 1 discloses that the case is provided therein with a partition wall in which a part of the power control device is installed on an upper vertically oriented surface and another part is installed on a lower vertically oriented surface, and a cooling passage through which a liquid refrigerant flows is provided inside the partition wall. Prior Art Documents Patent Documents

[0003] Patent Document 1 Japanese Unexamined Patent Application Publication No. 2022-161294 Summary of the Invention Problem to be Solved by the Invention

[0004] Incidentally, in an integrated electromechanical unit, the power control device is mounted adjacent to the motor in the vertical direction above, and in order to miniaturize it, it is necessary to shorten the physical distance between the motor and the power control device. In that case, for example, in the integrated electromechanical device described in Patent Document 1, the power control device and the motor are more likely to exchange heat through ambient temperature, the case, etc. It is desirable that the power control device does not generate heat. Also, since the motor is prone to demagnetization and performance degradation due to heat generation, it is desirable that the motor does not generate heat. Electric vehicles equipped with a cooling oil passage that sprays oil discharged by an oil pump onto the motor for cooling purposes are also well known, and there is room for improvement in the use of this cooling oil passage.

[0005] The present invention was made against the above circumstances, and its objective is to provide an electric vehicle that can improve the cooling performance of the electric motor and power control device. [Means for solving the problem]

[0006] The gist of the first invention is (a) an electric motor, a power transmission device to which the electric motor is connected so as to transmit power, a drive battery, a power control device for controlling the power exchanged between the battery and the electric motor, a case for housing the drive device including the electric motor and the power transmission device and the power control device as an integrated electromechanical unit, and an oil pump for discharging oil, Discharged from the aforementioned oil pump The oil is used to cool the electric motor. As the oil is discharged by the aforementioned oil pump An electric vehicle comprising a cooling oil passage that sprays into the electric motor, (b) the power control device is positioned adjacent to the electric motor in the vertical direction above when mounted on the electric vehicle, and (c) the cooling oil passage is positioned between the electric motor and the power control device. The oil is then sprayed onto the electric motor and the power control device, respectively. It is the matter.

[0007] Furthermore, the second invention is an electric vehicle according to the first invention, further comprising a plurality of power lines that electrically connect the electric motor and the power control device, wherein the cooling oil passage is located between any two of the plurality of power lines.

[0009] Also, the 3 The present invention relates to the electric vehicle described in the second invention, wherein the power control device comprises an inverter having a three-phase bridge circuit of U-phase, V-phase, and W-phase, the electric motor is a three-phase AC synchronous motor driven by the inverter, and the plurality of power lines are three power lines carrying three-phase AC current of U-phase, V-phase, and W-phase.

[0011] Also, the 4 The invention of the first invention is the second invention described above. or The 3 The Clearly The electric vehicle described above further includes a terminal block that connects a plurality of motor-side power lines connected to the electric motor and a plurality of power control-side power lines connected to the power control device, wherein any two of the power lines are any two of the plurality of motor-side power lines arranged between the electric motor and the terminal block.

[0012] Also, the 5 The invention is derived from the first invention. 4In an electric vehicle according to any one of the inventions, the electric motor includes a first electric motor and a second electric motor, the drive unit is arranged such that, when mounted on the electric vehicle, the rotation axis of the first electric motor, the rotation axis of the second electric motor, and the rotation axis of the power transmission unit are each parallel to a horizontal direction perpendicular to the forward and backward direction of the electric vehicle, and the rotation axis of the second electric motor and the rotation axis of the first electric motor are arranged in the order from the top to the bottom in the vertical direction, the power control unit is arranged such that, when mounted on the electric vehicle, the lower vertical portion of the power control unit is positioned so as to overlap with the upper vertical portion of the second electric motor when viewed in the forward and backward direction, and the lower vertical portion is positioned above the first electric motor in the vertical direction, and the cooling oil passage is arranged between the first electric motor and the lower vertical portion of the power control unit.

[0013] Also, the 6 The invention is derived from the first invention. 5 In the electric vehicle described in any one of the inventions, the direction of the cooling oil passage is the same as the direction of the rotation axis of the electric motor. [Effects of the Invention]

[0014] According to the first invention described above, the oil discharged by the oil pump is used to cool the electric motor. As the oil is discharged by the oil pump The cooling oil passages that spray into the electric motor are located between the electric motor and a power control device positioned adjacent to the electric motor, vertically above it. The oil is then sprayed onto the electric motor and the power control device, respectively. As a result, both the electric motor and the power control device are cooled by the oil ejected from the cooling oil passage, which can suppress heat generation in both the electric motor and the power control device. Therefore, the cooling performance for the electric motor and the power control device can be improved.

[0015] Furthermore, according to the second invention, the cooling oil passage is located between any two of the multiple power lines that electrically connect the electric motor and the power control device. When the physical distance between the electric motor and the power control device is shortened, the power lines are shortened, which worsens the heat dissipation of the power lines and makes it easier for the electric motor and the power control device to exchange heat with each other. In contrast, according to the second invention, the power lines are cooled by the oil ejected from the cooling oil passage, and heat exchange between the electric motor and the power control device can be suppressed.

[0017] Also, the 3 According to this invention, the plurality of power lines are three power lines carrying U-phase, V-phase, and W-phase alternating currents, so the cooling oil passage is located between any two of the three power lines carrying the three-phase alternating currents. As a result, the power lines are cooled by the oil ejected from the cooling oil passage, and heat transfer between the motor and the power control device can be suppressed.

[0019] Also, the 4 According to this invention, the two power lines are any two of a plurality of motor-side power lines arranged between the motor and the terminal block. Therefore, the cooling oil passage is arranged between any two of the plurality of motor-side power lines. As a result, the power lines are cooled by the oil ejected from the cooling oil passage, and heat transfer between the motor and the power control device can be appropriately suppressed.

[0020] Also, the 5According to the invention, in the driving device, the rotation axis of the second electric motor and the rotation axis of the first electric motor are arranged in this order from the upper side to the lower side in the vertical direction. The power control device is arranged at a position where a lower portion in the vertical direction overlaps an upper portion in the vertical direction of the second electric motor when viewed in the forward-reverse direction, and the lower portion in the vertical direction is arranged above the first electric motor in the vertical direction. The cooling oil passage is arranged between the first electric motor and the lower portion in the vertical direction of the power control device. Thus, both the first electric motor and the lower portion in the vertical direction of the power control device are cooled by the oil ejected from the cooling oil passage, whereby heat generation of the electric motor and the power control device can be suppressed.

[0021] Further, said 6 According to the invention, the direction of the cooling oil passage is the same as the direction of the rotation axis of the electric motor. Accordingly, the cooling oil can flow down from the upper side in the vertical direction to the lower side in the vertical direction over the entire length in the direction of the rotation axis of the electric motor, so that the entire electric motor can be efficiently cooled. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] [Figure 1] It is a diagram illustrating an example of a schematic configuration of an electric vehicle to which the present invention is applied. [Figure 2] It is a diagram illustrating an example of an electrical configuration related to control of an electric motor and the like. [Figure 3] It is a diagram illustrating an example of a schematic configuration of an integrated electromechanical unit. [Figure 4] It is a diagram illustrating an example of a cooling system using oil. [Figure 5] It is a diagram illustrating an example of a structure of a case cover in a cooling system using oil. [Figure 6] It is a diagram illustrating an example of a cooling system in which cooling pipes are arranged between busbars. [Figure 7] It is a diagram showing an example of a mounting range of cooling pipes. [Figure 8] It is a diagram illustrating an example of a schematic configuration of an electric vehicle to which the present invention is applied, showing an embodiment different from the electric vehicle in FIG. 1. [Modes for carrying out the invention]

[0023] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. [Examples]

[0024] Figure 1 is a diagram illustrating an example of the schematic configuration of an electric vehicle 10 to which the present invention is applied. In Figure 1, the electric vehicle 10 is a hybrid vehicle equipped with an engine 12 that functions as a power source and a second electric motor MG2 that functions as a power source. The electric vehicle 10 also includes drive wheels 14, a power transmission device 16, and a first electric motor MG1.

[0025] The engine 12 is a known internal combustion engine. The drive wheels 14 are the left and right wheels of the electric vehicle 10 in the forward and backward directions. The power transmission device 16 is provided in the power transmission path between the engine 12 and the drive wheels 14, and in the power transmission path between the second electric motor MG2 and the drive wheels 14.

[0026] The first electric motor MG1 and the second electric motor MG2 are known rotating electric machines that each have the function of an engine that generates mechanical power from electric power and a generator that generates electric power from mechanical power, and are so-called motor generators. The first electric motor MG1 and the second electric motor MG2 are housed in a non-rotatable case 18, which is a non-rotating member attached to the vehicle body.

[0027] The power transmission device 16 includes a damper 20, an input shaft 22, a transmission unit 24, a compound gear 26, a driven gear 28, a driven shaft 30, a final gear 32, a differential gear 34, a reduction gear 36, etc., within a case 18. The power transmission device 16 also includes a pair of drive shafts 38 connected to the differential gear 34, etc.

[0028] The damper 20 is connected to the crankshaft 12a of the engine 12. The input shaft 22 functions as the input rotating member of the transmission unit 24. The input shaft 22 is connected to the damper 20 and, via the damper 20, is connected to the crankshaft 12a. The transmission unit 24 is connected to the input shaft 22. The compound gear 26 is the output rotating body of the transmission unit 24. The compound gear 26 has a drive gear 26a formed on a part of its outer circumference. The drive gear 26a is the output rotating member of the transmission unit 24. The driven gear 28 meshes with the drive gear 26a. The driven shaft 30 fixes the driven gear 28 and the final gear 32 so that they cannot rotate relative to each other. The final gear 32 has a smaller diameter than the driven gear 28 and meshes with the differential ring gear 34a. The reduction gear 36 has a smaller diameter than the driven gear 28 and meshes with the driven gear 28. The rotor shaft of the second electric motor MG2 is connected to the reduction gear 36, and the second electric motor MG2 is connected in a way that allows it to transmit power.

[0029] The power transmission device 16 configured in this way is suitably used in FF (front-engine, front-drive) or RR (rear-engine, rear-drive) vehicles. The power transmission device 16 transmits power output from the engine 12 to the driven gear 28 via the transmission unit 24. The power transmission device 16 also transmits power output from the second electric motor MG2 to the driven gear 28 via the reduction gear 36. The power transmission device 16 then transmits the power transmitted to the driven gear 28 to the drive wheels 14 sequentially via the driven shaft 30, final gear 32, differential gear 34, drive shaft 38, etc. The driven gear 28, driven shaft 30, and final gear 32 are transmission mechanisms that transmit power from the second electric motor MG2 to the differential gear 34, and transmission mechanisms that transmit power from the drive gear 26a to the differential gear 34. The differential gear 34 distributes power from the engine 12 and the second electric motor MG2 to the drive wheels 14. The drive shaft 38 transmits power from the differential gear 34 to the drive wheels 14. The second electric motor MG2 is connected to the drive wheels 14 in a manner that it can transmit power.

[0030] The transmission unit 24 comprises a first electric motor MG1 and a differential mechanism 40. The differential mechanism 40 is a known single-pinion type planetary gear system comprising a sun gear S, a carrier CA, and a ring gear R. The sun gear S is connected to the rotor shaft of the first electric motor MG1. In other words, the differential mechanism 40, which is part of the power transmission device 16, is connected to the first electric motor MG1 in a power-transmitting manner. The carrier CA is connected to the input shaft 22. In other words, the differential mechanism 40 is connected to the engine 12 in a power-transmitting manner via the input shaft 22, etc. The ring gear R is formed on a part of the inner circumferential surface of the compound gear 26 and is integrally connected to the drive gear 26a. In other words, the differential mechanism 40 is connected to the drive wheels 14 in a power-transmitting manner.

[0031] The differential mechanism 40 functions as a differential mechanism that produces a differential action, to which the engine 12 is connected in a manner that enables power transmission. The first electric motor MG1 is a differential motor connected to the differential mechanism 40 in a manner that enables power transmission. The differential mechanism 40 is a power split mechanism that mechanically divides the power of the engine 12 input to the carrier CA between the first electric motor MG1 and the drive gear 26a. The transmission unit 24 is a known electric transmission mechanism in which the differential state of the differential mechanism 40 is controlled by controlling the operating state of the first electric motor MG1.

[0032] The power transmission device 16 has a first axis CL1, a second axis CL2, a third axis CL3, and a fourth axis CL4. These four axes CL1, CL2, CL3, and CL4 are parallel to each other. The first axis CL1 is the axis of the input shaft 22 and the rotor shaft of the first motor MG1. In other words, the first axis CL1 is the rotation axis of the first motor MG1. The gearbox 24 and the first motor MG1 are arranged around the first axis CL1. The second axis CL2 is the axis of the driven shaft 30. The driven gear 28 and the final gear 32 are arranged around the second axis CL2. In other words, the second axis CL2 is the rotation axis of the driven gear 28, the driven shaft 30, and the final gear 32. The third axis CL3 is the axis of the rotor shaft of the second motor MG2. In other words, the third axis CL3 is the rotation axis of the second electric motor MG2. The second electric motor MG2 and the reduction gear 36 are arranged around the third axis CL3. The fourth axis CL4 is the axis of the drive shaft 38 and the axis of the differential gear 34. In other words, the fourth axis CL4 is the rotation axis of the drive shaft 38 and the differential gear 34. The differential gear 34 is arranged around the fourth axis CL4. The second axis CL2 and the fourth axis CL4 are the rotation axes of the power transmission device 16.

[0033] The case 18 comprises a housing 18a, a case body 18b, and a cover 18c. The engine block 12b of the engine 12 is connected to the open portion of the housing 18a on the engine 12 side. The housing 18a and the case body 18b are integrally connected by fasteners such as bolts so that the open portion of the housing 18a on the opposite side of the engine 12 and the open portion of the case body 18b on the engine 12 side are aligned. The case body 18b and the cover 18c are integrally connected by fasteners so that the open portion of the case body 18b on the opposite side of the engine 12 is closed by the cover 18c. The case body 18b is a case that includes a partition wall (not shown) that separates a gear chamber Rg which houses the transmission unit 24, driven gear 28, differential gear 34, etc., and a motor chamber Rm which houses the first electric motor MG1 and the second electric motor MG2. The case body 18b, together with the housing 18a, forms a gear chamber Rg. The case body 18b, together with the cover 18c, forms a motor chamber Rm. In this way, the case 18 houses the first electric motor MG1, the second electric motor MG2, and the power transmission device 16, excluding the drive shaft 38, etc.

[0034] Figure 2 illustrates an example of the electrical configuration related to the control of the first motor MG1 and the second motor MG2. In Figure 2, the electric vehicle 10 is further equipped with a high-voltage battery 50, an auxiliary battery 52, and a power control unit 54.

[0035] The high-voltage battery 50 is a rechargeable DC power source, such as a nickel-metal hydride secondary battery or a lithium-ion battery. The high-voltage battery 50 is connected to the power control unit 54. The stored power from the high-voltage battery 50 is supplied to, for example, the second motor MG2 via the power control unit 54. In addition, the high-voltage battery 50 is supplied with power from the power generation control of the first motor MG1 and power from the regenerative control of the second motor MG2 via the power control unit 54. The high-voltage battery 50 is a battery for driving the vehicle.

[0036] The power control unit 54 includes a DC-DC converter 56, an electric motor control device 58, a boost converter 60, and an inverter 62. The power control unit 54 is a power control device that controls the power exchanged between the high-voltage battery 50 and the first electric motor MG1 and the second electric motor MG2, respectively.

[0037] The DC-DC converter 56 is connected to the high-voltage battery 50. The DC-DC converter 56 functions as a charging device that steps down the voltage of the high-voltage battery 50 to a voltage equivalent to that of the auxiliary battery 52 and charges the auxiliary battery 52. ​​The auxiliary battery 52 supplies power to operate the auxiliary equipment, motor control device 58, and electronic control device 70 (described later) provided in the electric vehicle 10.

[0038] The boost converter 60 includes reactors and switching elements (not shown). The boost converter 60 is a buck-boost circuit that has the function of boosting the voltage of the high-voltage battery 50 and supplying it to the inverter 62, and the function of stepping down the voltage converted to DC by the inverter 62 and supplying it to the high-voltage battery 50.

[0039] The inverter 62 includes an MG1 power module 64, an MG2 power module 66, and the like. The MG1 power module 64 is equipped with multiple transistors that can be switched on and off as switching elements to convert DC current to three-phase AC current, and constitutes a three-phase bridge circuit of U-phase, V-phase, and W-phase. The electric vehicle 10 is further equipped with a busbar 68, and the first electric motor MG1 is electrically connected to the MG1 power module 64 (i.e., the inverter 62) by the busbar 68. The busbar 68 is a power line that electrically connects the first electric motor MG1 and the power control unit 54, and includes multiple busbars 68u, 68v, and 68w. The multiple busbars 68u, 68v, and 68w are three power lines that carry U-phase, V-phase, and W-phase three-phase AC current. The MG2 power module 66 has the same configuration as the MG1 power module 64, so the description of the MG2 power module 66 is omitted. The first motor MG1 and the second motor MG2 are three-phase AC synchronous motors, each driven by an inverter 62.

[0040] The inverter 62 converts the DC current from the boost converter 60 into AC current to drive the first motor MG1 and the second motor MG2. The inverter 62 converts the AC current generated by the first motor MG1 using the power of the engine 12, and the AC current generated by the second motor MG2 using regenerative braking, into DC current. The inverter 62 supplies the AC current generated by the first motor MG1 as power to drive the second motor MG2, according to the driving conditions.

[0041] The electric vehicle 10 is further equipped with an electronic control unit 70, a communication line 72, and the like. The electronic control unit 70 transmits and receives signals to and from a DC-DC converter 56, an electric motor control unit 58, and the like via the communication line 72. The electronic control unit 70 performs various controls on the electric vehicle 10 based on signals from, for example, sensors (not shown). The communication line 72 is, for example, a well-known CAN (Controller Area Network) communication line.

[0042] The motor control device 58 controls the boost converter 60 and inverter 62 based on commands from the electronic control device 70, thereby controlling the first motor MG1 and the second motor MG2. For example, the motor control device 58 converts the DC current from the high-voltage battery 50 into AC current used by the first motor MG1 and the second motor MG2, respectively. The motor control device 58 drives the first motor MG1 to ensure the amount of power generated necessary for supplying power to the second motor MG2 and charging the high-voltage battery 50. The motor control device 58 drives the second motor MG2 based on the output requirement value corresponding to the driver's requested torque. The motor control device 58 makes the second motor MG2 function as a generator according to the amount of regenerative braking required.

[0043] Figure 3 is a diagram illustrating an example of the schematic configuration of the drive unit 90. Figure 3 is a side view of the electric vehicle 10 from the left side. In Figure 3, the transaxle 92 and the power control unit 54 are housed in the same case 18 as the drive unit 90. The drive unit 90 is a unit in which the transaxle 92 and the power control unit 54 are integrated, i.e., a mechatronic integrated unit. The transaxle 92 is a drive device that includes power transmission devices 16 (26a, 28, 32, 34a, 36, etc.), a first electric motor MG1, and a second electric motor MG2. Note that the vertical direction, forward / reverse direction, and vehicle width direction (see Figure 5) in the figure indicate the direction when mounted on the electric vehicle 10. The vehicle width direction is the axial direction of the first axle CL1, the second axle CL2, the third axle CL3, and the fourth axle CL4.

[0044] Case 18 further comprises a protective plate 18d in addition to the housing 18a, case body 18b, and cover 18c described above. The case body 18b has a bottom wall and side walls that extend vertically upward from the outer edge of the bottom wall on the front and rear sides in the forward and backward directions, and has an opening at the top in the vertical direction. The protective plate 18d is a plate-shaped member that closes the opening at the top in the vertical direction of the case body 18b. The case body 18b has a partition wall (not shown) inside, which divides the interior into two spaces: a lower space A, which is the space at the bottom in the vertical direction, and an upper space B, which is the space at the top in the vertical direction.

[0045] When mounted on the electric vehicle 10, the transaxle 92 is housed in the lower space A of the case body 18b or in the housing 18a.

[0046] The power control unit 54 is housed in the upper space B of the case body 18b when mounted on the electric vehicle 10. The upper space B includes the surplus space B1 created by the arrangement of the first electric motor MG1 and the second electric motor MG2, and the uppermost space B2 above the second electric motor MG2 in the vertical direction. The length of the surplus space B1 in the forward and reverse direction is shorter than that of the uppermost space B2. When mounted on the electric vehicle 10, the power control unit 54 is positioned adjacent to the first electric motor MG1 in the vertical direction, above it.

[0047] The surplus space B1 houses components of the power control unit 54 that are relatively short in length and relatively easy to replace, such as the DC-DC converter 56 and the reactor (not shown) of the boost converter 60.

[0048] Referring to Figure 3, in the mounted state on the electric vehicle 10, the transaxle 92 is arranged such that the first axle CL1, second axle CL2, third axle CL3, and fourth axle CL4 are each parallel to the horizontal direction perpendicular to the forward and backward direction of the electric vehicle 10. Furthermore, in the mounted state on the electric vehicle 10, the positions of the first axle CL1, second axle CL2, third axle CL3, and fourth axle CL4 are arranged in the order of second motor MG2, driven shaft 30, first motor MG1, and differential gear 34 from top to bottom in the vertical direction, and in the order of first motor MG1, driven shaft 30, differential gear 34, and second motor MG2 from front to rear in the forward and backward direction. Focusing on the first motor MG1 and the second motor MG2, the transaxle 92, when mounted on the electric vehicle 10, is arranged vertically from top to bottom in the order of the third axis CL3 and the first axis CL1. This ensures that the distances between the first axis CL1, the second axis CL2, the third axis CL3, and the fourth axis CL4 are appropriately maintained, while reducing the vertical size of the transaxle 92. As a result, the arrangement of the first motor MG1 and the second motor MG2 creates surplus space B1, and the uppermost space B2 is created vertically above the second motor MG2. The power control unit 54 is mounted in this upper space B (B1 + B2).

[0049] In its mounted state on the electric vehicle 10, the power control unit 54 is positioned vertically above the transaxle 92. In addition, in its mounted state on the electric vehicle 10, the lower vertical portion of the power control unit 54 is positioned so that it overlaps with the upper vertical portion of the transaxle 92, particularly the second electric motor MG2, when viewed horizontally, particularly in the forward and backward directions. Alternatively, in its mounted state on the electric vehicle 10, the lower vertical portion of the power control unit 54 is positioned vertically above the first electric motor MG1. The lower vertical portion of the power control unit 54 consists of components (e.g., a DC-DC converter 56, a reactor) housed in the surplus space B1 of the power control unit 54.

[0050] The power control unit 54 is mounted in the space created by the reduction in the vertical size of the transaxle 92, and space is created vertically above the drive unit 90.

[0051] In the electric vehicle 10, the first electric motor MG1 and the second electric motor MG2 are cooled by oil FLD. Oil FLD is also used to cool the power control unit 54. The cooling system using oil FLD will be described in detail below, using the first electric motor MG1 as an example.

[0052] Figure 4 illustrates an example of a cooling system using oil FLD. Figure 5 illustrates an example of the structure of the cover 18c of case 18 in a cooling system using oil FLD. Figure 4 is a side view of the electric vehicle 10 from the left side. Figure 5 is a rear, right-side perspective view of the electric vehicle 10.

[0053] In Figures 1, 4, and 5, the electric vehicle 10 further comprises an electric oil pump 74, an oil reservoir 76, a strainer 78, an intake oil passage 80, a discharge oil passage 82, an intermediate oil passage 84, a cooling pipe 86, etc., within the case 18. The electric vehicle 10 further comprises an oil cooler 88 mounted on the outside of the case 18, for example, the cover 18c.

[0054] The oil reservoir 76 is an oil reservoir located at the bottom of the gear chamber Rg where oil FLD accumulates. The electric oil pump 74 is driven based on commands from the electronic control unit 70 and is an oil pump that draws oil FLD from the oil reservoir 76 through the strainer 78 and the suction oil passage 80, and discharges oil FLD to the discharge oil passage 82.

[0055] The oil cooler 88 is a heat exchanger that cools the oil FLD through heat exchange. In the oil cooler 88, the oil FLD is cooled using, for example, an electric or mechanical cooling fan, or a refrigerant such as coolant.

[0056] The oil FLD discharged into the discharge oil passage 82 is supplied to the intermediate oil passage 84 via the oil cooler 88. The intermediate oil passage 84 is an oil passage downstream of the oil cooler 88, and is the oil passage between the oil cooler 88 and the cooling pipe 86, and is the oil passage that guides the oil FLD to the cooling pipe 86.

[0057] The cooling pipe 86 is a cooling oil passage that injects oil FLD discharged from the electric oil pump 74 into the first electric motor MG1 for cooling purposes. The cooling pipe 86 is an overhanging pipe positioned adjacent to the first electric motor MG1 in the vertical direction. The cooling pipe 86 is arranged in the vehicle width direction. In other words, the direction of the cooling pipe 86 is the same as the direction of the first axis CL1. While there are overhanging cooling and shaft core cooling methods for cooling electric motors, at least overhanging cooling is employed for cooling the first electric motor MG1 in the electric vehicle 10.

[0058] In the drive unit 90, where the power control unit 54 is positioned vertically above the transaxle 92, the power control unit 54 is positioned vertically above and adjacent to the first motor MG1. Considering the reduction of the vertical size of the drive unit 90, it is necessary to shorten the physical distance between the first motor MG1 and the power control unit 54. Therefore, heat exchange between the first motor MG1 and the power control unit 54 is facilitated.

[0059] Therefore, the cooling pipe 86 is positioned between the first electric motor MG1 and the power control unit 54. For example, the cooling pipe 86 is positioned between the first electric motor MG1 and the lower vertical portion of the power control unit 54 (i.e., the components housed in the surplus space B1). The cooling pipe 86 is provided with a plurality of ejection holes that open toward, for example, the first electric motor MG1 and the power control unit 54, and oil FLD is ejected from these ejection holes. For cooling the first electric motor MG1, oil FLD is ejected from the top, causing the oil FLD to flow down from the upper vertical side to the lower vertical side, thereby cooling the entire first electric motor MG1. By positioning the power control unit 54 above the cooling pipe 86, the number of cooling pipes 86 is reduced, and cooling can be performed more efficiently.

[0060] By arranging a cooling pipe 86 between the first electric motor MG1 and the power control unit 54, cooling by oil FLD can be applied to both the first electric motor MG1 and the power control unit 54. This maximizes the cooling efficiency of oil FLD and minimizes the space required for the cooling pipe 86.

[0061] There is heat conduction between the first motor MG1 and the power control unit 54 via the busbar 68. When the physical distance between the first motor MG1 and the power control unit 54 is shortened, the busbar 68 is shortened. As a result, the heat dissipation of the busbar 68 deteriorates, making it easier for the first motor MG1 and the power control unit 54 to exchange heat with each other.

[0062] Therefore, the cooling pipe 86 is positioned between any two of the busbars 68u, 68v, and 68w. This allows the heat transfer path between the first motor MG1 and the power control unit 54 to be cooled, and suppresses heat transfer between the first motor MG1 and the power control unit 54.

[0063] Busbars 68 with short paths have poorer heat dissipation compared to busbars 68 with long paths. By injecting oil FLD into busbars 68 with short paths, heat absorption can be efficiently suppressed. Any two busbars 68 with a cooling pipe 86 placed between them are, for example, the two busbars 68 with short paths from among a plurality of busbars 68u, 68v, and 68w.

[0064] Figure 6 illustrates an example of a cooling system in which cooling pipes 86 are arranged between busbars 68. In Figure 6, the busbars 68 include MG busbars 68m and PCU busbars 68p. The MG busbars 68m are multiple motor-side power lines connected to the first motor MG1 from among a plurality of busbars 68u, 68v, and 68w, and include a plurality of MG busbars 68mu, 68mv, and 68mw. The PCU busbars 68p are multiple power control device-side power lines connected to the power control unit 54 from among a plurality of busbars 68u, 68v, and 68w, and include a plurality of PCU busbars 68pu, 68pv, and 68pw. The electric vehicle 10 further includes terminal blocks 94 that connect the plurality of MG busbars 68mu, 68mv, and 68mw and the plurality of PCU busbars 68pu, 68pv, and 68pw. In busbar 68u, MG busbar 68mu and PCU busbar 68pu are connected at terminal block 94. In busbar 68v, MG busbar 68mv and PCU busbar 68pv are connected at terminal block 94. In busbar 68w, MG busbar 68mw and PCU busbar 68pw are connected at terminal block 94. Any two busbars 68 in which a cooling pipe 86 is placed are any two MG busbars 68m from the multiple MG busbars 68mu, 68mv, and 68mw that are placed between the first motor MG1 and terminal block 94. In other words, the cooling pipe 86 is placed between any two MG busbars 68m from the multiple MG busbars 68mu, 68mv, and 68mw. Any two of these MG busbars 68m are, for example, two MG busbars 68mv and 68mw with short paths from among multiple MG busbars 68mu, 68mv, and 68mw.

[0065] As described above, in this embodiment, the cooling pipe 86 is positioned between the first electric motor MG1 and the power control unit 54. As a result, both the first electric motor MG1 and the power control unit 54 are cooled by the oil FLD ejected from the cooling pipe 86, and heat generation in the first electric motor MG1 and the power control unit 54 can be suppressed. Therefore, the cooling performance for the first electric motor MG1 and the power control unit 54 can be improved.

[0066] Furthermore, according to this embodiment, the cooling pipe 86 is positioned between any two of the multiple busbars 68u, 68v, and 68w. As a result, the busbars 68 are cooled by the oil FLD ejected from the cooling pipe 86, and heat transfer between the first electric motor MG1 and the power control unit 54 can be suppressed.

[0067] Furthermore, according to this embodiment, any two of the busbars 68 are the two busbars 68 with the shortest paths among the multiple busbars 68u, 68v, and 68w. As a result, the busbars 68 with short paths, which have poorer heat dissipation compared to the busbars 68 with long paths, are cooled, and heat transfer between the first motor MG1 and the power control unit 54 can be efficiently suppressed.

[0068] Furthermore, according to this embodiment, any two of the busbars 68 are any two of the multiple MG busbars 68mu, 68mv, and 68mw arranged between the first motor MG1 and the terminal block 94. As a result, the power lines are cooled by the oil ejected from the cooling oil passage, and heat transfer between the first motor MG1 and the power control unit 54 can be appropriately suppressed.

[0069] Furthermore, according to this embodiment, the cooling pipe 86 is positioned between the first electric motor MG1 and the lower vertical portion of the power control unit 54. As a result, both the first electric motor MG1 and the lower vertical portion of the power control unit 54 are cooled by the oil FLD ejected from the cooling pipe 86, thereby suppressing heat generation in the first electric motor MG1 and the power control unit 54.

[0070] Furthermore, according to this embodiment, the direction of the cooling pipe 86 is the same as the direction of the first axis CL1, that is, the vehicle width direction. As a result, the cooling oil FLD can flow down from the vertically upper side to the vertically lower side along the entire length of the first electric motor MG1 in the vehicle width direction, enabling efficient cooling of the entire first electric motor MG1.

[0071] Although embodiments of the present invention have been described in detail above with reference to the drawings, the present invention is also applicable to other embodiments.

[0072] For example, in the above-described embodiment, the same over-cooling method as used for the first motor MG1 may be employed for cooling the second motor MG2. The present invention can also be applied to the second motor MG2. Certain effects of the present invention can be obtained if the cooling pipe is positioned between the motors (MG1, MG2) and the power control unit 54. Figure 7 shows an example of the mounting range of the cooling pipe. In Figure 7, the cooling pipe should be positioned between the thick lines C and D.

[0073] Furthermore, in the above-described embodiment, the transaxle 92 and the power control unit 54 were housed in separate spaces within the case 18, separated by a partition wall. However, they may also be housed in the same space without a partition wall.

[0074] Furthermore, in the above-described embodiment, a mechanical oil pump may be used as the oil pump for discharging the oil FLD, either in place of or in addition to the electric oil pump 74.

[0075] Furthermore, in the above-described embodiment, the electric vehicle may be an electric vehicle 100 equipped with a drive motor MG, as shown in Figure 8. In Figure 8, the main difference between the electric vehicle 100 and the electric vehicle 10 of the above-described embodiment is that the electric vehicle 100 does not have the components around the first axis CL1 (engine 12, transmission unit 24 including the first motor MG1). Also, the motor MG of the electric vehicle 100 corresponds to the second motor MG2 of the electric vehicle 10. In the electric vehicle 100, for example, at the arrangement position of the components of the transaxle 92 shown in Figure 3, the first motor MG1 is removed and the second motor MG2 functions as the motor MG.

[0076] Furthermore, in the above-described embodiment, the electric vehicle may be a series hybrid vehicle comprising an engine, a drive motor that functions as a power source, and a power supply motor that is connected to the engine in a manner that can transmit power and generates electricity using the engine's power. In such a series hybrid vehicle, the power transmission path between the engine and the drive wheels may be interrupted or connected by the operation of a clutch. Alternatively, the electric vehicle may be a parallel hybrid vehicle comprising an engine, a power transmission device that transmits power from the engine to the drive wheels, and an electric motor to which power is transmitted to the drive wheels via the power transmission device.

[0077] Furthermore, in the above-described embodiment, the first motor MG1, the second motor MG2, and motor MG are not limited to three-phase AC synchronous motors. For example, the first motor MG1, the second motor MG2, and motor MG may be other motors such as single-phase synchronous motors or induction motors. The power line electrically connecting the motor and the power control device can be any power line that carries the current to drive the motor.

[0078] It should be noted that the above-described embodiment is merely one example, and the present invention can be implemented in various modified and improved forms based on the knowledge of those skilled in the art. [Explanation of Symbols]

[0079] 10: Electric vehicle 16: Power transmission device 18: Case 50: High-voltage battery (battery for driving) 54: Power control unit (power control device) 62: Inverter 64: MG1 power module (three-phase bridge circuit) 66: MG2 power module (three-phase bridge circuit) 68 (68u, 68v, 68w): Busbar (power line) 68m (68mu, 68mv, 68mw): MG busbar (power line on the motor side) 68p (68pu, 68pv, 68pw): PCU busbar (power line on the power control device side) 74: Electric oil pump (oil pump) 86: Cooling pipe (cooling oil passage) 90: Drive unit (mechatronic unit) 92: Transaxle (drive device) 94: Terminal block CL1: First axis (rotation axis of the first motor) CL2: Second axis (rotation axis of the power transmission device) CL3: Third axis (rotation axis of the second motor) CL4: Fourth axis (rotation axis of the power transmission unit) FLD: Oil MG1: First motor (motor, synchronous motor) MG2: Second motor (motor, synchronous motor) 100: Electric vehicle (electric vehicle) MG: Motor

Claims

1. An electric vehicle comprising: an electric motor; a power transmission device to which the electric motor is connected in a manner that enables power transmission; a drive battery; a power control device for controlling the power exchanged between the battery and the electric motor; a case housing the drive device including the electric motor and the power transmission device and the power control device as an integrated electromechanical unit; an oil pump for discharging oil; and a cooling oil passage for which the oil discharged from the oil pump is injected into the electric motor as the oil pump discharges, for the purpose of cooling the electric motor, The power control device is positioned adjacent to the electric motor in the vertical direction above when mounted on the electric vehicle. The cooling oil passage is located between the electric motor and the power control device, and the oil is injected into the electric motor and the power control device, respectively, in this electric vehicle.

2. The system further comprises a plurality of power lines that electrically connect the electric motor and the power control device. The electric vehicle according to claim 1, characterized in that the cooling oil passage is located between any two of the plurality of power lines.

3. The aforementioned power control device includes an inverter having a three-phase bridge circuit for U-phase, V-phase, and W-phase, The motor is a three-phase AC synchronous motor driven by the inverter, The electric vehicle according to claim 2, characterized in that the plurality of power lines are three power lines carrying three-phase alternating currents of U-phase, V-phase, and W-phase.

4. The system further includes a terminal block that connects a plurality of motor-side power lines connected to the motor and a plurality of power control-side power lines connected to the power control device, among the plurality of power lines. The electric vehicle according to claim 2, characterized in that any two of the aforementioned power lines are any two of the plurality of motor-side power lines arranged between the motor and the terminal block.

5. The aforementioned electric motor includes a first electric motor and a second electric motor, In the mounted state on the electric vehicle, the drive unit is arranged such that the rotation axis of the first electric motor, the rotation axis of the second electric motor, and the rotation axis of the power transmission unit are each parallel to the horizontal direction perpendicular to the forward and backward direction of the electric vehicle, and the rotation axis of the second electric motor and the rotation axis of the first electric motor are arranged in the order from top to bottom in the vertical direction. The power control device, when mounted on the electric vehicle, is positioned such that its lower vertical portion overlaps with the upper vertical portion of the second electric motor when viewed in the forward and backward directions, and its lower vertical portion is positioned vertically above the first electric motor. The electric vehicle according to any one of claims 1 to 4, characterized in that the cooling oil passage is arranged between the first electric motor and the vertically lower portion of the power control device.

6. The electric vehicle according to claim 1, characterized in that the direction of the cooling oil passage is the same as the direction of the rotation axis of the electric motor.

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