Electric vehicle

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 equipped with a cooling oil passage through which oil is sprayed onto an electric motor for cooling the electric motor. [Background technology]

[0002] There is a well-known electric vehicle that includes an electric motor, a power transmission device to which the electric motor is connected so as to be capable of transmitting power, a drive battery, a power control device that controls power exchanged between the battery and the electric motor, and a case that houses the drive device including the electric motor and the power transmission device and the power control device as an electromechanical integrated unit. For example, the electromechanical integrated device described in Patent Document 1 is such an example. Patent Document 1 discloses that the case includes a partition wall in which a part of the power control device is installed on the vertical upper surface and another part is installed on the vertical lower 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] JP 2022-161294 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the electromechanical integrated unit, the power control device is mounted adjacent to the motor in the vertical direction above, and in order to reduce the size, it is necessary to shorten the physical distance between the motor and the power control device. In this way, for example, in the electromechanical integrated unit described in Patent Document 1, the other parts of the power control device and the motor are made to easily receive heat from each other via the ambient temperature or the case. It is desirable that the power control device suppresses heat generation. In addition, since the motor is easily demagnetized by heat generation and its performance is reduced, it is desirable that the heat generation is suppressed. Electric vehicles equipped with a cooling oil passage that sprays oil discharged by an oil pump onto the motor to cool the motor are also well known, and there is room for improvement in the use of this cooling oil passage.

[0005] The present invention has been made in light of the above circumstances, and an object of the present invention is to provide an electric vehicle capable of improving the cooling performance for the electric motor and the power control device. [Means for solving the problem]

[0006] The gist of the first invention is that (a) an electric vehicle comprising an electric motor, a power transmission device to which the electric motor is connected so as to be capable of transmitting power, a drive battery, a power control device that controls the power exchanged between the battery and the electric motor, a case that houses the drive device including the electric motor and the power transmission device and the power control device as an integrated mechanical and electrical unit, an oil pump that discharges oil, and a cooling oil passage that sprays the oil onto the electric motor for cooling the electric motor, (b) the power control device is arranged adjacent to and vertically above the electric motor when mounted on the electric vehicle, and (c) the cooling oil passage is arranged between the electric motor and the power control device.

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

[0008] A third aspect of the present invention is the electric vehicle according to the second aspect of the present invention, wherein the any two power lines are two power lines having short paths among the plurality of power lines.

[0009] A fourth invention is an electric vehicle according to the second invention, wherein the power control device includes 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 multiple power lines are three power lines carrying three-phase AC current of U-phase, V-phase, and W-phase.

[0010] A fifth aspect of the present invention is the electric vehicle according to the fourth aspect of the present invention, wherein the any two power lines are two power lines having shorter routes among the three power lines.

[0011] A sixth invention is an electric vehicle according to any one of the second to fifth inventions, further comprising a terminal block connecting a plurality of motor side power lines among the plurality of power lines connected to the electric motor and a plurality of power control device side power lines among the plurality of power lines connected to the power control device, and the two power lines are two motor side power lines among the plurality of motor side power lines arranged between the electric motor and the terminal block.

[0012] A seventh invention is an electric vehicle according to any one of the first to sixth inventions, wherein the electric motor includes a first electric motor and a second electric motor, and the drive device 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 device are each parallel to a horizontal direction perpendicular to the forward and backward travel 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 from above to below in the vertical direction, and the power control device is arranged such that, when mounted on the electric vehicle, the vertically lower portion overlaps with the vertically upper portion of the second electric motor when viewed in the forward and backward travel direction, and the vertically lower portion is arranged above the first electric motor in the vertical direction, and the cooling oil passage is arranged between the first electric motor and the vertically lower portion of the power control device.

[0013] According to an eighth aspect of the present invention, in the electric vehicle according to any one of the first to seventh aspects of the present invention, the direction of the cooling oil passage is the same as the direction of the rotation axis of the electric motor. Effect of the Invention

[0014] According to the first aspect of the present invention, the cooling oil passage through which the oil discharged by the oil pump is sprayed onto the electric motor for cooling the electric motor is disposed between the electric motor and the electric power control device disposed adjacent to and vertically above the electric motor. This allows both the electric motor and the electric power control device to be cooled by the oil sprayed from the cooling oil passage, and the heat generation of the electric motor and the electric power control device can be suppressed. This improves the cooling performance for the electric motor and the electric power control device.

[0015] According to the second aspect of the present invention, the cooling oil passage is disposed between any two of a plurality of power lines electrically connecting 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 also shortened, which deteriorates the heat dissipation performance of the power lines and makes it easier for the electric motor and the power control device to receive heat from each other. In contrast, according to the second aspect of the present invention, the power lines are cooled by the oil ejected from the cooling oil passage, and the mutual reception of heat between the electric motor and the power control device can be suppressed.

[0016] According to the third aspect of the present invention, the any two power lines are two power lines having short paths among a plurality of power lines, whereby the power lines having short paths, which have poorer heat dissipation properties than power lines having long paths, are cooled, and heat reception between the electric motor and the power control device can be efficiently suppressed.

[0017] According to the fourth aspect of the present invention, the plurality of power lines are three power lines carrying three-phase AC current of phases U, V, and W, and the cooling oil passage is disposed between any two of the three power lines carrying three-phase AC current. This allows the power lines to be cooled by oil ejected from the cooling oil passage, and can suppress the mutual heat reception between the electric motor and the power control device.

[0018] According to the fifth aspect of the present invention, the any two power lines are the two power lines having the shortest paths among the three power lines, so that the power lines having the shortest paths, which have poorer heat dissipation properties than the power lines having the longest paths, are cooled, and the heat transfer between the electric motor and the power control device can be efficiently suppressed.

[0019] According to the sixth aspect of the present invention, the two electric power lines are two electric motor side electric power lines among a plurality of electric motor side electric power lines arranged between the electric motor and the terminal block. Therefore, the cooling oil passage is arranged between two electric motor side electric power lines among the plurality of electric motor side electric power lines. This allows the electric power lines to be cooled by oil ejected from the cooling oil passage, and the mutual heat reception between the electric motor and the electric power control device can be appropriately suppressed.

[0020] According to the seventh aspect of the present invention, the drive device is arranged vertically from top to bottom with the rotation axis of the second electric motor and the rotation axis of the first electric motor in that order. The power control device is arranged in a position where the vertically lower portion overlaps with the vertically upper portion of the second electric motor when viewed in the forward / reverse direction, and the vertically lower portion is arranged vertically above the first electric motor. The cooling oil passage is arranged between the first electric motor and the vertically lower portion of the power control device. As a result, both the first electric motor and the vertically lower portion of the power control device are cooled by oil ejected from the cooling oil passage, and heat generation of the electric motor and the power control device can be suppressed.

[0021] According to the eighth aspect of the present invention, the direction of the cooling oil passage is the same as the direction of the rotation axis of the motor, so that the cooling oil can flow down from the vertically upper side to the vertically lower side over the entire length of the rotation axis of the motor, thereby efficiently cooling the entire motor. [Brief description of the drawings]

[0022] [Figure 1] 1 is a diagram illustrating an example of a schematic configuration of an electric vehicle to which the present invention is applied; [Diagram 2] FIG. 2 is a diagram illustrating an example of an electrical configuration related to control of an electric motor, etc. [Diagram 3] FIG. 2 is a diagram illustrating an example of a schematic configuration of an electromechanical integrated unit. [Figure 4] FIG. 1 is a diagram illustrating an example of a cooling system using oil. [Diagram 5] 1A and 1B are diagrams illustrating an example of a structure of a case cover in a cooling system using oil. [Figure 6] FIG. 1 is a diagram illustrating an example of a cooling system in which cooling pipes are arranged between bus bars. [Figure 7] FIG. 4 is a diagram showing an example of a mounting range of a cooling pipe. [Figure 8] FIG. 2 is a diagram for explaining an example of a schematic configuration of an electric vehicle to which the present invention is applied, which is an embodiment different from the electric vehicle of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0024] Fig. 1 is a diagram illustrating an example of a schematic configuration of an electric vehicle 10 to which the present invention is applied. In Fig. 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 is an electric motor that also 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 left and right wheels in the forward and backward directions of the electric vehicle 10. The power transmission device 16 is provided on a power transmission path between the engine 12 and the drive wheels 14, and on a 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, so-called motor generators, each of which has a function as a motor that generates mechanical power from electric power and a function as a generator that generates electric power from mechanical power. The first electric motor MG1 and the second electric motor MG2 are provided in a non-rotatable case 18, which is a non-rotating member attached to the vehicle body.

[0027] The power transmission device 16 includes, within a case 18, a damper 20, an input shaft 22, a transmission section 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. 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 an input rotating member of the transmission unit 24. The input shaft 22 is connected to the damper 20, and is connected to the crankshaft 12a via the damper 20. The transmission unit 24 is connected to the input shaft 22. The compound gear 26 is a rotating body on the output side of the transmission unit 24. The compound gear 26 has a drive gear 26a formed on a part of its outer circumferential surface. The drive gear 26a is an output rotating member of the transmission unit 24. The driven gear 28 is meshed 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 is in mesh with the driven gear 28. A rotor shaft of the second electric motor MG2 is connected to the reduction gear 36, and the second electric motor MG2 is connected to the reduction gear 36 so as to be capable of transmitting power.

[0029] The power transmission device 16 thus configured is suitable for use in FF (front engine, front drive) or RR (rear engine, rear drive) vehicles. The power transmission device 16 transmits the power output from the engine 12 to the driven gear 28 via the transmission unit 24. The power transmission device 16 also transmits the power output from the second electric motor MG2 to the driven gear 28 via the reduction gear 36. The power transmission device 16 transmits the power transmitted to the driven gear 28 to the driving wheels 14 via the driven shaft 30, the final gear 32, the differential gear 34, the drive shaft 38, and the like in this order. The driven gear 28, the driven shaft 30, and the final gear 32 are transmission mechanisms that transmit the power from the second electric motor MG2 to the differential gear 34, and transmit the 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 so as to be able to transmit power.

[0030] The transmission unit 24 includes a first electric motor MG1 and a differential mechanism 40. The differential mechanism 40 is a known single-pinion type planetary gear device including a sun gear S, a carrier CA, and a ring gear R. The sun gear S is connected to a rotor shaft of the first electric motor MG1. That is, the differential mechanism 40, which is a part of the power transmission device 16, is connected to the first electric motor MG1 as an electric motor so as to be capable of transmitting power. The carrier CA is connected to the input shaft 22. That is, the differential mechanism 40 is connected to the engine 12 via the input shaft 22 and the like so as to be capable of transmitting power. The ring gear R is formed on a part of the inner circumferential surface of the compound gear 26, and is connected integrally to the drive gear 26a. That is, the differential mechanism 40 is connected to the drive wheels 14 so as to be capable of transmitting power.

[0031] The differential mechanism 40 functions as a differential mechanism that generates a differential action and is connected to the engine 12 so as to be capable of transmitting power. The first electric motor MG1 is a differential motor that is connected to the differential mechanism 40 so as to be capable of transmitting power. The differential mechanism 40 is a power split mechanism that mechanically splits the power of the engine 12 input to the carrier CA to the first electric motor MG1 and the drive gear 26a. The transmission 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 one another. The first axis CL1 is the axis of the input shaft 22 and the rotor shaft of the first electric motor MG1. That is, the first axis CL1 is the rotation axis of the first electric motor MG1. The transmission unit 24 and the first electric motor MG1 are disposed 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 disposed around the second axis CL2. That is, 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 electric motor MG2. That is, 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 disposed 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. That is, the fourth axis CL4 is the rotation axis of the drive shaft 38 and the differential gear 34. The differential gear 34 is disposed 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 includes a housing 18a, a case body 18b, and a cover 18c. An engine block 12b of the engine 12 is connected to the housing 18a at an open portion on the engine 12 side. The housing 18a and the case body 18b are integrally connected by fasteners such as bolts so that an open portion of the housing 18a on the opposite side to the engine 12 and an 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 to the engine 12 is closed by the cover 18c. The case body 18b is a case including a partition wall (not shown) that separates a gear chamber Rg that houses the transmission unit 24, the driven gear 28, the differential gear 34, etc., from a motor chamber Rm that houses the first electric motor MG1 and the second electric motor MG2. The case body 18b and the housing 18a form a gear chamber Rg. The case body 18b and the cover 18c form a motor chamber Rm. In this manner, the case 18 accommodates the first electric motor MG1, the second electric motor MG2, and the power transmission device 16 excluding the drive shaft 38 and the like.

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

[0035] The high-voltage battery 50 is a chargeable and dischargeable DC power source, such as a secondary battery, such as a nickel-metal hydride secondary battery or a lithium-ion battery. The high-voltage battery 50 is connected to a power control unit 54. Stored power is supplied from the high-voltage battery 50 to, for example, the second electric motor MG2 via the power control unit 54. In addition, power resulting from power generation control of the first electric motor MG1 and power resulting from regeneration control of the second electric motor MG2 are supplied to the high-voltage battery 50 via the power control unit 54. The high-voltage battery 50 is a driving battery.

[0036] The power control unit 54 includes a DC-DC converter 56, a 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 motor MG1 and the second motor MG2.

[0037] The DCDC converter 56 is connected to the high-voltage battery 50. The DCDC 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 to charge the auxiliary battery 52. ​​The auxiliary battery 52 supplies power to operate the accessories provided in the electric vehicle 10, the motor control device 58, an electronic control device 70 (described later), and the like.

[0038] The boost converter 60 includes a reactor, a switching element, etc. (not shown). The boost converter 60 is a step-up / step-down circuit having a function of stepping up the voltage of the high-voltage battery 50 and supplying it to the inverter 62, and a 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 includes a plurality of transistors that are driven on and off as switching elements to convert a direct current into a three-phase alternating current, and constitutes a three-phase bridge circuit of U-phase, V-phase, and W-phase. The electric vehicle 10 further includes a bus bar 68, and the first electric motor MG1 is electrically connected to the MG1 power module 64 (i.e., the inverter 62) by the bus bar 68. The bus bar 68 is a power line that electrically connects the first electric motor MG1 and the power control unit 54, and includes a plurality of bus bars 68u, 68v, and 68w. The plurality of bus bars 68u, 68v, and 68w are three power lines that pass three-phase alternating current of U-phase, V-phase, and W-phase. The MG2 power module 66 has a similar configuration to the MG1 power module 64, and therefore a description of the MG2 power module 66 will be omitted. The first motor MG1 and the second motor MG2 are each a three-phase AC synchronous motor driven by an inverter 62.

[0040] The inverter 62 converts the DC current from the boost converter 60 into AC current for driving the first electric motor MG1 and the second electric motor MG2. The inverter 62 converts the AC current generated by the first electric motor MG1 by the power of the engine 12 and the AC current generated by the second electric motor MG2 by regenerative braking into DC current. The inverter 62 supplies the AC current generated by the first electric motor MG1 as power for driving the second electric motor MG2 depending on the running state.

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

[0042] The motor control device 58 controls the boost converter 60 and the inverter 62 based on a command from the electronic control device 70, and controls the first motor MG1 and the second motor MG2. For example, the motor control device 58 converts a direct current from the high-voltage battery 50 into an alternating current used by each of the first motor MG1 and the second motor MG2. The motor control device 58 drives the first motor MG1 to ensure the amount of power generation required 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 an output requirement value corresponding to the torque required by the driver. The motor control device 58 causes the second motor MG2 to function as a generator according to the amount of regenerative braking required.

[0043] FIG. 3 is a diagram for explaining an example of a schematic configuration of the drive unit 90. FIG. 3 is a side view from the left side of the electric vehicle 10. In FIG. 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, that is, an electromechanical integrated unit. The transaxle 92 is a drive device including a power transmission device 16 (26a, 28, 32, 34a, 36, etc.), a first electric motor MG1, and a second electric motor MG2. The vertical direction, forward / rearward direction, and vehicle width direction (see FIG. 5) in the figure indicate directions in a mounted state in the electric vehicle 10. The vehicle width direction is the axial direction of each of the first axis CL1, the second axis CL2, the third axis CL3, and the fourth axis CL4.

[0044] The case 18 further includes 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 extending vertically upward from the outer periphery of the bottom wall at the front and rear sides in the forward and rearward travel direction, 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, and the interior is divided by the partition wall into two spaces: a lower space A, which is a space at the bottom in the vertical direction, and an upper space B, which is a space at the top in the vertical direction.

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

[0046] The power control unit 54 is housed in an upper space B in the case body 18b when mounted on the electric vehicle 10. The upper space B includes a surplus space B1 created by the arrangement of the first electric motor MG1 and the second electric motor MG2, and a top space B2 vertically above the second electric motor MG2. The surplus space B1 has a shorter length in the forward and reverse directions than the top space B2. When mounted on the electric vehicle 10, the power control unit 54 is disposed adjacent to and vertically above the first electric motor MG1.

[0047] The surplus space B1 accommodates, for example, the DCDC converter 56 and a reactor (not shown) provided in the boost converter 60, taking into consideration that these are relatively short components of the power control unit 54 and relatively easy to replace.

[0048] 3, when the transaxle 92 is mounted on the electric vehicle 10, the first axis CL1, the second axis CL2, the third axis CL3, and the fourth axis CL4 are arranged so that they are parallel to a horizontal direction perpendicular to the forward and backward travel direction of the electric vehicle 10. When the transaxle 92 is mounted on the electric vehicle 10, the positions of the first axis CL1, the second axis CL2, the third axis CL3, and the fourth axis CL4 of the transaxle 92 are, from top to bottom in the vertical direction, in the order of second electric motor MG2, driven shaft 30, first electric motor MG1, and differential gear 34, and, from front to rear in the forward and backward travel direction, in the order of first electric motor MG1, driven shaft 30, differential gear 34, and second electric motor MG2. Focusing on the first electric motor MG1 and the second electric motor MG2, the transaxle 92 is arranged in the order of the third axis CL3 and the first axis CL1 from top to bottom in the vertical direction when mounted on the electric vehicle 10. This allows the vertical size of the transaxle 92 to be reduced while appropriately ensuring the inter-axis distances between the first axis CL1, the second axis CL2, the third axis CL3, and the fourth axis CL4. Thus, the arrangement of the first electric motor MG1 and the second electric motor MG2 creates a surplus space B1, and an uppermost space B2 is created above the second electric motor MG2 in the vertical direction. The power control unit 54 is mounted in this upper space B (B1+B2).

[0049] The power control unit 54 is disposed vertically above the transaxle 92 when mounted on the electric vehicle 10. In addition, the power control unit 54 is disposed at a position where a vertically lower portion of the power control unit 54 overlaps with a vertically upper portion of the transaxle 92, particularly the second electric motor MG2, when viewed horizontally, particularly in the forward / rearward direction, when mounted on the electric vehicle 10. In other words, the power control unit 54 is disposed vertically above the first electric motor MG1 when mounted on the electric vehicle 10. The vertically lower portion of the power control unit 54 is, for example, a component (e.g., the DC-DC converter 56, a reactor) accommodated 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 reduced vertical size of the transaxle 92, and space is created vertically above the drive unit 90.

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

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

[0053] 1, 4 and 5, the electric vehicle 10 further includes 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, and the like within the case 18. The electric vehicle 10 further includes an oil cooler 88 attached to the case 18, for example, to the outside of the cover 18c.

[0054] The oil reservoir 76 is an oil reservoir provided at the bottom of the gear chamber Rg to store the oil FLD. The electric oil pump 74 is driven based on a command from the electronic control device 70 to suck the oil FLD from the oil reservoir 76 through a strainer 78 and an intake oil passage 80 and discharge the oil FLD to a discharge oil passage 82.

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

[0056] The oil FLD discharged to 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 an oil passage between the oil cooler 88 and the cooling pipe 86, and is an oil passage that guides the oil FLD to the cooling pipe 86.

[0057] The cooling pipe 86 is a cooling oil passage through which the oil FLD discharged from the electric oil pump 74 is sprayed onto the first electric motor MG1 for cooling the first electric motor MG1. The cooling pipe 86 is an overhanging pipe arranged adjacent to and vertically above the first electric motor MG1. 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 line CL1. Methods for cooling electric motors include overhanging cooling and shaft core cooling, and in the electric vehicle 10, at least overhanging cooling is adopted for cooling the first electric motor MG1.

[0058] In the drive unit 90 in which the power control unit 54 is disposed vertically above the transaxle 92, the power control unit 54 is disposed vertically above and adjacent to the first electric motor MG1. In consideration of reducing the vertical size of the drive unit 90, it is necessary to shorten the physical distance between the first electric motor MG1 and the power control unit 54. Therefore, it is made easier for the first electric motor MG1 and the power control unit 54 to mutually receive heat.

[0059] Therefore, the cooling pipe 86 is disposed between the first electric motor MG1 and the power control unit 54. For example, the cooling pipe 86 is disposed between the first electric motor MG1 and the vertically lower portion of the power control unit 54 (i.e., the components accommodated in the surplus space B1). The cooling pipe 86 is provided with, for example, a plurality of ejection holes that open toward each of the first electric motor MG1 and the power control unit 54, and the oil FLD is ejected from the ejection holes. The first electric motor MG1 is cooled by ejecting the oil FLD from the top, so that the oil FLD flows down from the vertically upper side to the vertically lower side, and the entire first electric motor MG1 can be cooled. The power control unit 54 is disposed vertically above the cooling pipe 86, so that the number of cooling pipes 86 is reduced, and cooling can be performed efficiently.

[0060] By disposing the cooling pipes 86 between the first electric motor MG1 and the power control unit 54, it is possible to perform cooling by the oil FLD for both the first electric motor MG1 and the power control unit 54. This makes it possible to maximize the cooling efficiency by the oil FLD and minimize the arrangement space for the cooling pipes 86.

[0061] Heat is conducted between the first electric motor MG1 and the power control unit 54 via the bus bar 68. When the physical distance between the first electric motor MG1 and the power control unit 54 is shortened, the bus bar 68 is shortened. Therefore, the heat dissipation performance of the bus bar 68 deteriorates, and it becomes easier for the first electric motor MG1 and the power control unit 54 to mutually receive heat.

[0062] Therefore, the cooling pipe 86 is disposed between any two of the bus bars 68u, 68v, 68w. This makes it possible to cool the heat receiving path between the first electric motor MG1 and the power control unit 54, and to suppress the mutual heat reception between the first electric motor MG1 and the power control unit 54.

[0063] Bus bars 68 with short paths have poorer heat dissipation properties than bus bars 68 with long paths. By spraying oil FLD onto bus bars 68 with short paths, it is possible to efficiently suppress heat reception. Any two bus bars 68 between which a cooling pipe 86 is disposed are, for example, two bus bars 68 with short paths among the multiple bus bars 68u, 68v, and 68w.

[0064] FIG. 6 is a diagram illustrating an example of a cooling system in which cooling pipes 86 are arranged between bus bars 68. In FIG. 6, the bus bars 68 include an MG bus bar 68m and a PCU bus bar 68p. The MG bus bar 68m is one of the bus bars 68u, 68v, and 68w that are a plurality of electric motor side power lines connected to the first electric motor MG1, and includes a plurality of MG bus bars 68mu, 68mv, and 68mw. The PCU bus bar 68p is one of the bus bars 68u, 68v, and 68w that are a plurality of electric power control device side power lines connected to the power control unit 54, and includes a plurality of PCU bus bars 68pu, 68pv, and 68pw. The electric vehicle 10 further includes a terminal block 94 that connects the plurality of MG bus bars 68mu, 68mv, and 68mw to the plurality of PCU bus bars 68pu, 68pv, and 68pw. In bus bar 68u, MG bus bar 68mu and PCU bus bar 68pu are connected to each other at terminal block 94. In bus bar 68v, MG bus bar 68mv and PCU bus bar 68pv are connected to each other at terminal block 94. In bus bar 68w, MG bus bar 68mw and PCU bus bar 68pw are connected to each other at terminal block 94. Any two bus bars 68 between which a cooling pipe 86 is arranged are any two MG bus bars 68m of the multiple MG bus bars 68mu, 68mv, 68mw arranged between the first electric motor MG1 and terminal block 94. In other words, the cooling pipe 86 is arranged between any two MG bus bars 68m of the multiple MG bus bars 68mu, 68mv, 68mw. These two MG bus bars 68m are, for example, the two MG bus bars 68mv, 68mw having the shortest paths among the multiple MG bus bars 68mu, 68mv, 68mw.

[0065] As described above, according to this embodiment, the cooling pipe 86 is disposed 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 from 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 disposed between any two of the bus bars 68u, 68v, 68w. This allows the oil FLD ejected from the cooling pipe 86 to cool the bus bars 68, thereby suppressing the mutual heat reception between the first electric motor MG1 and the power control unit 54.

[0067] Furthermore, according to this embodiment, the any two bus bars 68 are the two bus bars 68 with the shortest paths among the multiple bus bars 68u, 68v, 68w. As a result, the bus bars 68 with the shortest paths, which have poorer heat dissipation properties than the bus bars 68 with the longest paths, are cooled, and heat reception between the first electric motor MG1 and the power control unit 54 can be efficiently suppressed.

[0068] Furthermore, according to this embodiment, the any two bus bars 68 are any two MG bus bars 68m of the multiple MG bus bars 68mu, 68mv, 68mw arranged between the first electric motor MG1 and the terminal block 94. This allows the power lines to be cooled by oil ejected from the cooling oil passages, and the mutual heat reception between the first electric motor MG1 and the power control unit 54 can be appropriately suppressed.

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

[0070] Furthermore, according to this embodiment, the direction of the cooling pipes 86 is the same as the direction of the first axis CL1, i.e., the vehicle width direction, so that the cooling oil FLD can flow down from the vertically upper side to the vertically lower side over the entire length of the first electric motor MG1 in the vehicle width direction, thereby efficiently cooling the entire first electric motor MG1.

[0071] Although the embodiment of the present invention has been described in detail above with reference to the drawings, the present invention can be applied to other embodiments.

[0072] For example, in the above-mentioned embodiment, the second motor MG2 may be cooled by overcooling similar to that of the first motor MG1. The present invention can also be applied to the second motor MG2. A certain effect of the present invention can be obtained as long as the cooling pipes are arranged between the motors (MG1, MG2) and the power control unit 54. FIG. 7 is a diagram showing an example of the mounting range of the cooling pipes. In FIG. 7, the cooling pipes may be arranged between the thick lines C and D.

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

[0074] In the above-described embodiment, a mechanical oil pump may be used instead of or in addition to the electric oil pump 74 as the oil pump that discharges the oil FLD.

[0075] In the above-mentioned embodiment, the electric vehicle may be an electric vehicle 100 equipped with a driving electric motor MG as shown in Fig. 8. In Fig. 8, the electric vehicle 100 differs from the electric vehicle 10 of the above-mentioned embodiment mainly in that it does not include components around the first axis CL1 (the engine 12, the transmission 24 including the first electric motor MG1). In addition, the electric motor MG of the electric vehicle 100 corresponds to the second electric motor MG2 of the electric vehicle 10. In the electric vehicle 100, for example, in the position of the components of the transaxle 92 shown in Fig. 3, the first electric motor MG1 is eliminated and the second electric motor MG2 functions as the electric motor MG.

[0076] In the above-mentioned embodiment, the electric vehicle may be a series hybrid vehicle including an engine, a driving electric motor that functions as a power source, and an electric motor that is connected to the engine so as to be capable of transmitting power and that generates power using the power of the engine. In such a series hybrid vehicle, the power transmission path between the engine and the drive wheels may be disconnected or connected by the operation of a clutch. Alternatively, the electric vehicle may be a parallel hybrid vehicle including an engine, a power transmission device that transmits power from the engine to the drive wheels, and an electric motor that transmits power to the drive wheels via the power transmission device.

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

[0078] It should be noted that the above is merely one embodiment, and the present invention can be embodied 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): Bus bar (power line) 68m (68mu, 68mv, 68mw): MG bus bar (electric motor side power line) 68p (68pu, 68pv, 68pw): PCU bus bar (power control device side power line) 74: Electric oil pump (oil pump) 86: Cooling pipe (cooling oil passage) 90: Drive unit (mechanical integrated unit) 92: Transaxle (drive device) 94: Terminal block CL1: First axis (rotation axis of first electric motor) CL2: Second axis (rotation axis of power transmission device) CL3: Third axis (rotation axis of the second motor) CL4: Fourth axis (rotation axis of the power transmission device) 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 so as to be capable of transmitting power; a drive battery; a power control device that controls power exchanged between the battery and the electric motor; a case that houses the drive device including the electric motor and the power transmission device and the power control device as an integrated mechanical and electrical unit; an oil pump that discharges oil; and a cooling oil passage that sprays the oil onto the electric motor for cooling the electric motor, the power control device is disposed adjacent to and above the electric motor in a vertical direction when the power control device is mounted on the electric vehicle, The cooling oil passage is disposed between the electric motor and the power control device.

2. The power supply device further includes a plurality of power lines electrically connecting the electric motor and the power control device, 2. The electric vehicle according to claim 1, wherein the cooling oil passage is disposed between any two of the plurality of power lines.

3. 3. The electric vehicle according to claim 2, wherein the any two power lines are two power lines having short routes among the plurality of power lines.

4. The power control device includes 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, 3. The electric vehicle according to claim 2, wherein the plurality of power lines are three power lines through which three-phase AC current of U-phase, V-phase, and W-phase flows.

5. 5. The electric vehicle according to claim 4, wherein the any two power lines are two power lines having shorter routes among the three power lines.

6. a terminal block for connecting a plurality of electric motor side electric power lines connected to the electric motor among the plurality of electric power lines and a plurality of electric power control device side electric power lines connected to the electric power control device among the plurality of electric power lines, 3. The electric vehicle according to claim 2, wherein the any two electric power lines are any two electric motor side electric power lines among the plurality of electric motor side electric power lines arranged between the electric motor and the terminal block.

7. The electric motor includes a first electric motor and a second electric motor, When the drive device is 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 device are each arranged parallel to a horizontal direction perpendicular to a forward / rearward traveling 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 this order from above to below in the vertical direction, When the power control device is mounted on the electric vehicle, the vertically lower portion is disposed at a position overlapping with the vertically upper portion of the second electric motor as viewed in the forward / reverse direction, and the vertically lower portion is disposed above the first electric motor in the vertical direction, 7. The electric vehicle according to claim 1, wherein the cooling oil passage is disposed between the first electric motor and a portion of the power control device that is vertically lower than the first electric motor.

8. 2. The electric vehicle according to claim 1, wherein the direction of the cooling oil passage is the same as the direction of a rotation axis of the electric motor.

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