Electric vehicle

Abstract

An electric vehicle is provided with a rotary electric machine, a motor case that houses the rotary electric machine, a cooling mechanism that supplies oil to the rotary electric machine to cool the rotary electric machine, an inverter that drives the rotary electric machine, and a connection member that electrically connects the inverter and the rotary electric machine. The electric vehicle has a configuration in which the inverter is integrated with the motor case. The cooling mechanism has a supply hole that is provided at a position higher than the rotary electric machine inside the motor case and that ejects the oil toward the connection member. The connection member has a portion that is provided radially inward of an outer peripheral surface of the rotary electric machine at a position higher than a center of rotation of the rotary electric machine and lower than the supply hole inside the motor case.

Description

Technical Field

[0001] The present invention relates to electric vehicles. Background Art

[0002] Japanese Patent Application Laid-Open No. 2007-159314 discloses a cooling structure for cooling the inverter by supplying lubricating oil scraped off by a differential gear to the inverter in an electric vehicle having an integrated inverter and a motor housing. Summary of the Invention

[0003] However, the structure described in Japanese Patent Application Laid-Open No. 2007-159314 requires a passage to guide the scraped lubricating oil to the inverter, which results in a larger structure. Furthermore, when the motor is not driven, the differential gear does not rotate and the lubricating oil cannot be scraped, which raises the concern that the lubricating oil will not be able to cool the motor and inverter.

[0004] The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide an electric vehicle in which a motor and an inverter can be cooled using oil without increasing the size of the structure.

[0005] A technical solution of the present invention is an electric vehicle comprising: a rotating motor; a motor housing for accommodating the rotating motor; a cooling mechanism for supplying oil to the rotating motor to cool the rotating motor; an inverter for driving the rotating motor; and a connecting member for electrically connecting the inverter to the rotating motor, the electric vehicle having a structure in which the inverter and the motor housing are integrated, wherein the cooling mechanism has a supply hole, which is arranged inside the motor housing at a position above the rotating motor, and sprays the oil toward the connecting member, and the connecting member has a portion arranged radially inward of the outer peripheral surface of the rotating motor at a position above the rotation center of the rotating motor and below the supply hole inside the motor housing.

[0006] According to this configuration, the oil supply mechanism for supplying oil to the rotating electrical machine can supply oil to the connecting member between the inverter and the rotating electrical machine.

[0007] Furthermore, the inverter may be arranged in a space surrounded by a first plane flush with the upper surface of the motor housing, a second plane flush with the front or rear surface of the motor housing, and an outer surface of the motor housing.

[0008] This configuration improves vehicle mounting flexibility through a compact and low-profile mechatronic structure integrating the inverter and motor housing. Furthermore, it is adaptable to various transaxle types. Furthermore, by positioning the inverter inward relative to the front or rear surface of the motor housing, the inverter is protected by the motor housing in the event of an electric vehicle collision, ensuring the safety of the inverter's high voltage.

[0009] Furthermore, a portion of the connecting member may be provided at the same position as the supply hole in the axial direction of the rotating electrical machine.

[0010] According to this configuration, the oil ejected from the supply hole can easily reach the connecting member.

[0011] Furthermore, the electric vehicle may further include a cable for supplying electric power from a battery to the inverter, wherein the cable extends from an upper surface side or a front surface side of the inverter.

[0012] According to this configuration, the direction in which the cable is drawn out from the converter can be changed without changing the unit in accordance with the position of the component to which the cable is connected.

[0013] Furthermore, the electric vehicle may further include an auxiliary component electrically connected to the inverter, wherein the auxiliary component is arranged above the motor case or integrated with an upper surface of the motor case.

[0014] According to this configuration, it is possible to achieve miniaturization and lowering of the structure including the auxiliary components.

[0015] Furthermore, the cooling mechanism may include a cooling pipe disposed above the rotating electric machine within the motor housing and configured to spray the oil toward the rotating electric machine to cool the rotating electric machine, and the supply hole may be provided in the cooling pipe.

[0016] According to this configuration, the oil can be supplied to the connection member between the inverter and the rotating electrical machine using the cooling pipe that supplies oil to the rotating electrical machine.

[0017] Alternatively, the electric vehicle may further include a power transmission device having a drive shaft disposed on a different axis from that of the rotating electric machine. Alternatively, the motor housing may be integrated with a transaxle case housing the power transmission device, the interior of the motor housing may be in communication with the interior of the transaxle case, and the oil may lubricate the power transmission device.

[0018] In the present invention, the oil supply mechanism for supplying oil to the rotating electrical machine enables oil to be supplied to the connecting member between the inverter and the rotating electrical machine. This allows the rotating electrical machine and the inverter to be cooled using oil without increasing the size of the structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like reference numerals represent like elements, and wherein:

[0020] Figure 1 It is a diagram schematically showing a motor and an inverter included in the electric vehicle according to the embodiment.

[0021] Figure 2 This is a schematic diagram for explaining the internal structure of the motor case.

[0022] Figure 3 This is a diagram for explaining oil supply to a bus bar.

[0023] Figure 4 This is a diagram schematically showing a transaxle case that houses a power transmission device having a multi-shaft structure.

[0024] Figure 5 This is a diagram for explaining the connection positions of cables.

[0025] Figure 6 This is a diagram showing another example of the connection position of the cable.

[0026] Figure 7 This is a diagram for explaining the arrangement of the charger relative to the motor housing. DETAILED DESCRIPTION

[0027] Hereinafter, an electric vehicle according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. However, the present disclosure is not limited to the embodiment described below.

[0028] Figure 1 It is a diagram schematically showing a motor and an inverter included in the electric vehicle according to the embodiment. Figure 2 Schematic diagram for explaining the internal structure of a motor housing. An electric vehicle 1 includes a motor 10 and an inverter 20. The electric vehicle 1 uses the motor 10 as a power source for traveling.

[0029] The motor 10 comprises: an annular stator 12 fixed to a motor housing 11 in a non-rotatable manner; an annular rotor 13 disposed on the inner circumference of the stator 12; and a rotor shaft 14 connected to the inner circumference of the rotor 13. The motor housing 11 is a housing member that houses the motor 10. The stator 12, the rotor 13, and the rotor shaft 14 are housed inside the motor housing 11. The stator 12 is arranged as shown in FIG. Figure 2As shown, the motor 10 is constructed to include a stator core 15 and a stator coil 16. The stator coil 16 is wound around the stator core 15. The stator coil 16 forms coil ends on both axial ends of the stator core 15. The rotor 13 is a rotating member that rotates integrally with the rotor shaft 14. Permanent magnets 17 are embedded in the interior of the rotor 13. The rotor shaft 14 is rotatably supported relative to the motor housing 11 via a pair of bearings arranged on both sides in the axial direction. In this way, the motor 10 is a three-phase AC motor with permanent magnets 17 embedded in the rotor 13, and is a rotating electrical machine (electric generator) that performs both motor functions and power generation functions.

[0030] Furthermore, the motor 10 is mechanically coupled to the drive wheels via a power transmission device to generate torque for driving the electric vehicle 1. During braking of the electric vehicle 1, the motor 10 can also receive input of kinetic energy from the electric vehicle 1 to generate electricity (regeneration). For example, if the electric vehicle 1 is a hybrid vehicle, the motor 10 is mechanically coupled to the engine, enabling both regeneration using the engine's power and assisting the engine's power.

[0031] The inverter 20 is a power conversion device that converts DC power supplied from the battery into AC power. The inverter 20 is housed inside the inverter case 21. The inverter case 21 is a housing member that houses the inverter 20 and is mounted on the motor case 11. In other words, the inverter 20 is integrated with the motor case 11. Figure 2 As shown, there are provided electronic components 22 housed inside the inverter case 21. The electronic components 22 are components inside the inverter and include a plurality of switching elements and diodes.

[0032] For example, the converter 20 includes: a U-phase arm including a p-side switching element and an n-side switching element; a V-phase arm including a p-side switching element and an n-side switching element; and a W-phase arm including a p-side switching element and an n-side switching element. Each switching element of the converter 20 is composed of, for example, an IGBT (Insulated Gate Bipolar Transistor). In addition, each phase arm of the converter 20 is connected in parallel between a positive line connected to the positive pole of the battery and a negative line connected to the negative pole of the battery. In other words, the converter 20 is electrically connected to the battery. A diode that allows current to flow from the emitter side to the collector side is connected to the switching element of the converter 20. In addition, the midpoint between the p-side switching element and the n-side switching element of each phase arm is connected to each phase coil (U-phase coil, V-phase coil, W-phase coil) of the motor 10.

[0033] The battery is a power storage device that stores power to be supplied to the motor 10, and is, for example, a secondary battery such as a nickel-metal hydride battery or a lithium-ion battery. The battery is electrically connected to the motor 10 via the inverter 20. The power stored in the battery is supplied to the motor 10 via the inverter 20.

[0034] In addition, the converter 20 is electrically connected to the motor 10 via the busbar 30. The busbar 30 is a connecting member that electrically connects the motor 10 and the converter 20, and is a three-phase busbar. The busbar 30 is connected to the coils of each phase of the motor 10 and is also connected to the power lines of each phase of the converter 20. For example, the busbar 30 is connected to the motor 10. Figure 1 As shown, it has a U-phase bus 31 connected to the U-phase coil of the motor 10 and the U-phase power line of the converter 20, a V-phase bus 32 connected to the V-phase coil of the motor 10 and the V-phase power line of the converter 20, and a W-phase bus 33 connected to the W-phase coil of the motor 10 and the W-phase power line of the converter 20.

[0035] In addition, the busbar 30 is Figure 2 As shown, each phase includes a bus bar 30A on the inverter 20 side and a bus bar 30B on the motor 10 side. Bus bar 30A on the inverter 20 side protrudes from electronic components 22, and its tip (one end) is provided on terminal block 40. Terminal block 40 is a component for wiring connection.

[0036] like Figure 2 As shown, the terminal block 40 is provided through the motor housing 11 in a manner protruding from the inside of the converter housing 21 to the inside of the motor housing 11. Therefore, one end side of the busbar 30A on the converter 20 side is arranged inside the motor housing 11 in a state of being provided on the terminal block 40. Furthermore, inside the motor housing 11, the busbar 30A on the converter 20 side is connected to the busbar 30B on the motor 10 side. For example, the busbar 30A and the busbar 30B are connected by fastening with bolts. On the other hand, the other end of the busbar 30A on the converter 20 side is connected to the electronic component 22 (for example, the power lines of each phase of the converter 20) inside the converter housing 21.

[0037] Furthermore, busbar 30B on the motor 10 side protrudes from the coil end of stator coil 16 inside motor housing 11. One end of busbar 30B is connected to busbar 30A on the inverter 20 side at terminal block 40. The pair of busbars 30A and 30B are arranged so as to face each other and contact each other in the axial direction. The axial direction refers to the axial direction of rotor shaft 14 and represents the axial direction of motor 10. The rotation center O of rotor 13 and rotor shaft 14 is sometimes referred to as the rotation center O of motor 10.

[0038] Furthermore, the converter housing 21 is mounted on the outside of the motor housing 11. For example, the converter housing 21 may be Figure 2 As shown in FIG. 1 , the inverter 20 is integrated with the motor housing 11 by bolt fastening. Figure 3As shown, the inverter 20 is disposed within a space 103 defined by a first plane 101 flush with the top surface 11a of the motor housing 11, a second plane 102 flush with the front surface 11b of the motor housing 11, and the outer surface 11c of the motor housing 11. Specifically, the inverter 20 is disposed at a position lower than the top surface 11a of the motor housing 11. Furthermore, the inverter 20 is housed inward (toward the rear) of the front surface 11b of the motor housing 11.

[0039] Furthermore, a cooling pipe 50 for supplying oil to the motor 10 to cool the motor 10 is provided inside the motor housing 11. The cooling pipe 50 is arranged vertically above the motor 10, and oil flows inside the pipe.

[0040] The electric vehicle 1 includes a cooling mechanism for supplying oil to the motor 10 to cool the motor 10. The cooling mechanism includes an oil pump, a housing oil passage formed in the motor housing 11, a cooling pipe 50, and an oil reservoir. The oil reservoir is composed of, for example, an oil pan formed in the lower portion of the motor housing 11. The oil pump draws in the oil stored in the oil reservoir and discharges the oil into the housing oil passage. The housing oil passage is connected to the cooling pipe 50. Oil is pressurized within the housing oil passage and the cooling pipe 50. Furthermore, the cooling pipe 50, which is arranged above the stator 12, extends axially to circulate the oil in the axial direction within the motor housing 11.

[0041] The cooling pipe 50 is provided with a spray hole for spraying oil toward the motor 10. The spray hole is arranged above the motor 10 and opens toward the motor 10. Therefore, inside the motor housing 11, oil is sprayed vertically downward from the spray hole of the cooling pipe 50 toward the motor 10. In this way, oil is supplied to the motor 10 located below the cooling pipe 50. And, after being supplied to the motor 10, the oil is stored in the oil storage portion. In other words, the oil is circulated by the cooling mechanism in a manner that returns to the cooling pipe 50 again. In this way, the cooling mechanism is a circulation mechanism that circulates the oil.

[0042] In addition, in the electric vehicle 1, the busbar 30 is cooled by using the oil used to cool the motor 10. In other words, the cooling mechanism used to cool the motor 10 is used as the cooling mechanism for cooling the busbar 30 and the converter 20. Therefore, the cooling pipe 50 has a supply hole 51 for spraying oil to the busbar 30. In addition, Figure 3 The dashed arrows shown illustrate the direction in which the oil ejected from the supply hole 51 of the cooling pipe 50 is supplied.

[0043] The supply hole 51 is provided inside the motor housing 11 at a position above the motor 10 and is open toward the bus bar 30. The bus bar 30 is arranged vertically below the supply hole 51. Figure 1As shown, the portion of the busbar 30 disposed inside the motor housing 11 is located vertically above the rotation center O of the motor 10 and below the supply hole 51, and is located radially inward of the outer peripheral surface of the motor 10. The outer peripheral surface of the motor 10 represents the outer peripheral surface of the stator 12. Figure 3 As shown, the oil ejected from the supply hole 51 of the cooling pipe 50 can be supplied to the bus bar 30. Furthermore, the oil ejected toward the bus bar 30 is supplied to the inner surface of the motor housing 11 at the location where the inverter 20 is disposed. Therefore, the motor housing 11 at the location near the inverter 20 can be cooled by the oil.

[0044] In addition, the portion of the busbar 30 disposed inside the motor housing 11 is as shown in FIG. Figure 2 As shown, it is arranged axially outside of the coil end of the stator coil 16. Therefore, the supply hole 51 is arranged at a position corresponding to the axial position of the busbar 30. That is, a part of the busbar 30 is arranged at the same position as the supply hole 51 in the axial direction. That is, a part of the busbar 30 and the supply hole 51 are arranged at the same position in the axial direction. As a result, it is easy to supply the oil sprayed from the supply hole 51 to the busbar 30. In this way, the cooling pipe 50 is provided with a spray hole for spraying oil toward the motor 10 (a hole for motor cooling) and a supply hole 51 (a hole for busbar cooling) for spraying oil toward the busbar 30. In addition, the spray hole for motor cooling and the supply hole 51 for busbar cooling are arranged at different positions in the axial direction.

[0045] As described above, according to the embodiment, oil ejected from the cooling pipe 50 can be supplied to the busbar 30. By cooling the busbar 30 with oil, it is possible to prevent heat generated by the motor 10 from being transferred to the inverter 20 via the busbar 30. In other words, the cooling pipe 50, which supplies oil to the motor 10, can cool the busbar 30, the motor 10, and the inverter 20. Therefore, no additional components are required to cool the busbar 30, the motor 10, and the inverter 20. As a result, the structure does not increase in size, and oil can be used to cool the motor 10 and the inverter 20.

[0046] Inverter 20 integrated with motor housing 11 is disposed obliquely above motor 10 and below upper surface 11a of motor housing 11. Therefore, inverter 20 can be disposed at a low position, reducing the height of the unit (mechatronic structure).

[0047] Furthermore, the inverter 20 is mounted in a position that does not protrude from the upper surface 11a or front surface 11b of the motor housing 11. This allows for a lower profile and smaller mechatronic structure integrating the inverter 20 and the motor housing 11, increasing the flexibility of unit mounting. Furthermore, by arranging the inverter 20 inward of the front surface 11b of the motor housing 11, the inverter 20 is protected by the motor housing 11 in the event of a collision of the electric vehicle 1, ensuring the safety of the high voltage of the inverter 20.

[0048] Furthermore, the electric vehicle 1 is not limited to a hybrid vehicle, but may also be an electric vehicle.

[0049] In addition, in the electric vehicle 1, the structure of the power transmission device provided between the motor 10 and the drive wheel is not particularly limited. That is, the power transmission device may include a transmission with a single shaft structure (single shaft reducer), or may include a transmission with a multi-shaft structure (multi-shaft reducer). In the above-mentioned embodiment, a power transmission device in which the drive shaft and the motor 10 are arranged on the same axis is described. Therefore, as a modified example, an electric vehicle 1 equipped with a power transmission device including a multi-shaft reducer may also be provided. Figure 4 This modification is illustrated in FIG.

[0050] like Figure 4 As shown, in the modified example of electric vehicle 1, drive shaft 70 is arranged on a different axis from motor 10. In this case, motor housing 11 is integrated with transaxle case 60, which houses the power transmission device. Furthermore, the interior of motor housing 11 communicates with the interior of transaxle case 60. The oil used to lubricate the power transmission device within transaxle case 60 is the same as the oil used to cool motor 10 and busbar 30 within motor housing 11.

[0051] In this modified example, the inverter 20 is arranged at a position that does not protrude from the upper surface 60a and the front surface 60b of the transaxle case 60. Figure 4 As shown, the inverter 20 is disposed within a space 103 defined by a first plane 101 flush with the upper surface 60a of the transaxle case 60, a second plane 102 flush with the front surface 60b of the transaxle case 60, and the outer surface 60c of the transaxle case 60. For example, the upper surface 11a of the motor housing 11 and the upper surface 60a of the transaxle case 60 are formed at the same height. Therefore, the inverter 20 is disposed at a position lower than the upper surface 11a of the motor housing 11 and the upper surface 60a of the transaxle case 60. On the other hand, the front surface 60b of the transaxle case 60 is located forward of the front surface 11b of the motor housing 11. Therefore, the inverter 20 is housed inward (toward the rear) of the front surface 60b of the transaxle case 60.

[0052] The inverter 20 is not limited to being arranged on the front surface 11b side of the motor housing 11, but may be arranged on the rear surface side of the motor housing 11. For example, the inverter 20 may be arranged on a plane defined by a first plane 101 that is flush with the upper surface 11a of the motor housing 11 and a second plane 104 that is flush with the rear surface 11d of the motor housing 11. Figure 7 ), and a space 103 enclosed by the outer surface 11c of the motor housing 11. In this case, the inverter 20 is housed in a position further inward (frontward) than the rear surface 11d of the motor housing 11.

[0053] Furthermore, in the case of a structure in which the motor 10 is connected to a single-axis speed reducer, as shown in FIG. Figure 3 As shown in FIG. 1 , the inverter 20 can be mounted at a position that does not protrude from the upper surface 11a and the front and rear surfaces of the motor housing 11. In addition, in the case of a structure in which the motor 10 is connected to a multi-axis speed reducer, as shown in FIG. Figure 4 As shown, the inverter 20 can be mounted in a position where it does not protrude from the upper surface 60a and the front and rear surfaces of the transaxle case 60. This ensures high-voltage safety of the inverter 20, even in a multi-axis structure where the rotor shaft 14 and the drive shaft 70 are arranged in parallel.

[0054] In addition, the cable 80 for supplying high-voltage power from the battery to the inverter 20 may be connected to either the upper surface 21a side or the front surface 21b side of the inverter case 21. Figure 5 As shown, the cable 80 extends from the upper surface 21a of the converter housing 21, and the cable 80 is arranged above the converter housing 21 and the motor housing 11. Alternatively, Figure 6 As shown, cable 80 extends from front surface 21b of inverter housing 21, and is positioned in front of inverter housing 21 and motor housing 11. This allows the direction in which cable 80 is drawn to be changed without changing the unit depending on the position of the component to which cable 80 is connected (e.g., a battery, charger, etc.).

[0055] In addition, as another modification, auxiliary components 90 such as a charger may be arranged above the motor housing 11. Figure 7 As shown, the auxiliary component 90 is arranged in the space above the motor housing 11. Alternatively, the auxiliary component 90 may be integrated with the upper surface 11a of the motor housing 11 and the upper surface 21a of the inverter housing 21. Furthermore, the auxiliary component 90 is electrically connected to the inverter 20. In this case, the auxiliary component 90 and the inverter 20 may be connected via a cable 80 or a busbar (different from the busbar 30).

[0056] Furthermore, the oil pump included in the cooling mechanism is an electric pump. Therefore, even when the motor 10 is not driven, the electric pump can be driven, and oil can be supplied to the bus bar 30 and the motor 10 .

Claims

1. An electric vehicle, characterized in that: The electric vehicle comprises: Rotating electric machines; a motor housing for accommodating the rotating motor; a cooling mechanism for supplying oil to the rotating electrical machine to cool the rotating electrical machine; an inverter for driving the rotating electrical machine; as well as a connecting member electrically connecting the converter and the rotating electrical machine, The electric vehicle has a structure in which the inverter and the motor housing are integrated, wherein: The cooling mechanism includes a supply hole provided inside the motor housing at a position above the rotating electrical machine, and sprays the oil toward the connecting member. The connecting member has a portion provided radially inward of an outer peripheral surface of the rotating electric machine at a position above the rotation center of the rotating electric machine and below the supply hole inside the motor housing. The inverter is arranged in a space surrounded by a first plane, a second plane, and an outer surface of the motor housing, wherein the first plane is flush with the upper surface of the motor housing, and the second plane is flush with the front surface or the rear surface of the motor housing.

2. The electric vehicle according to claim 1, characterized in that A portion of the connecting member is provided at the same position as the supply hole in the axial direction of the rotating electrical machine.

3. The electric vehicle according to claim 1 or 2, characterized in that: The electric vehicle further includes a cable for supplying electric power from a battery to the inverter, wherein the cable extends from an upper surface side or a front surface side of the inverter.

4. The electric vehicle according to claim 1 or 2, characterized in that: The electric vehicle further includes auxiliary components electrically connected to the inverter. The auxiliary component is arranged above the motor housing or is integrated with the upper surface of the motor housing.

5. The electric vehicle according to claim 1 or 2, characterized in that: The cooling mechanism includes a cooling pipe disposed above the rotating electric machine within the motor housing and configured to spray the oil toward the rotating electric machine to cool the rotating electric machine. The supply hole is provided in the cooling pipe.

6. The electric vehicle according to claim 1 or 2, characterized in that: The electric vehicle further includes a power transmission device having a drive shaft disposed on an axis different from that of the rotating electric machine. The motor housing is integrated with the transmission axle housing that accommodates the power transmission device, and the interior of the motor housing is connected to the interior of the transmission axle housing. The oil lubricates the power transmission device.

Images