Electric vehicle drive system

Abstract

An electric vehicle drive device (1) comprises: a motor body part (5); a motor housing (6) that has a stator (5c) fixed to the inside thereof and is open on one axial side; a motor bracket (7) that covers one axial side of the stator (5c) and a rotor (5b) and has a central through-hole (7a) through which passes a shaft portion (5a1) on one side, extending from the rotor (5b) to one axial side; and a speed reducer (4) that reduces the rotational speed of the shaft (5a) and outputs the reduced rotational speed, wherein the motor bracket (7) has one or more outer through-holes (7b) positioned radially outer side of the central through-hole (7a) and axially penetrating the motor bracket (7), the motor housing (6) or the motor bracket (7) has a cylindrical cover section (13) that covers the radially outer side of the openings of the outer through-holes (7b) on one axial side over the entire circumference of the openings, and the end surface of the cover section (13) on one axial side is sealed over the entire circumference by abutting a case member (4a) of the speed reducer (4) with a seal member (14) therebetween.

Description

Technical Field

[0001] The present application relates to an electric vehicle drive device.

Background Art

[0002] In recent years, in consideration of environmental issues such as global warming, the replacement of conventional vehicles powered by internal combustion engines with electrified vehicles powered by electric motors that do not emit carbon dioxide during driving has been progressing rapidly. An electric vehicle drive device that drives an electric vehicle includes an electric motor, a speed reduction mechanism that reduces the speed of the electric motor and transmits the speed to an axle, and an inverter that converts direct-current power stored in a battery into arbitrary alternating-current power to efficiently drive and control the electric motor. Conventionally, the electric motor, the speed reduction mechanism, and the inverter have been manufactured separately and connected to each other, but a configuration in which these are integrated to achieve size reduction has been proposed (for example, Patent Document 1).

[0003] Patent Document 1 discloses an integrated configuration of a motor and a speed reducer. In this configuration, in the housing on the motor side, one plate-shaped portion is provided on the end face on the side that contacts the speed reducer. On the other hand, on the speed reducer side, one plate-shaped portion is provided at a portion facing the end face on the motor side. Therefore, when the motor and the speed reducer are assembled, the mating surfaces form a double case. When a separate motor unit and a separate speed reducer unit, both sealed from the outside, are respectively manufactured, inspected individually and then assembled together, such a double case configuration results. Although sealing from the outside is ensured, the double case configuration has the problem that the electric vehicle drive device cannot be reduced in size, cost and weight.

[0004] A configuration for an electric vehicle drive system that does not involve a double casing has been disclosed (for example, Patent Document 2). Patent Document 2 discloses a configuration in which, in the case that normally houses the motor, the end face portion on the reduction gear side is shared with the face of the reduction gear case. Compared to the case in which the motor and reduction gear are manufactured separately and then combined, this configuration avoids the creation of a double mating surface. Because there is no double mating surface, it is thought to contribute to miniaturization, cost reduction, and weight reduction of the electric vehicle drive system. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-150608 [Patent Document 2] Patent No. 5900012 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] In the above-mentioned Patent Document 2, it is possible to avoid having double mating surfaces. However, functional testing of the motor is only possible after the assembly, including the bearings at both ends of the rotor, is complete. In such a configuration, the motor only functions as a motor after the assembly process has progressed to the stage of combining the reduction gear and the motor. Therefore, it is not possible to test the motor alone, and only the performance of the system combined with the reduction gear can be obtained. As a result, it is difficult to grasp the variability of the motor alone and the variability of the reduction gear alone, which presents a challenge in ensuring the reliability of electric vehicle drive systems.

[0007] Furthermore, in motor assembly, precise alignment is performed using jigs and other tools to ensure that the small gap between the rotor and stator does not come into contact. In the above-mentioned Patent Document 2, one of the rotor bearings is located in the reduction gear case, so during the assembly process, the object to be assembled becomes a large product including the reduction gear, making precise assembly difficult and resulting in a problem of reduced productivity for electric vehicle drive systems.

[0008] Therefore, the present invention aims to provide an electric vehicle drive system that is miniaturized, cost-effective, and lightweight while ensuring reliability and improving productivity. [Means for solving the problem]

[0009] The electric vehicle drive system disclosed herein comprises a motor body having a shaft, a rotor that rotates integrally with the shaft, and a stator that surrounds the rotor from the radially outer side; a motor housing to which the stator is fixed internally and which has an opening on one side in the axial direction; a motor bracket that covers one side in the axial direction of the stator and the rotor and has a central through-hole through which one shaft portion extending from the rotor to one side in the axial direction passes; and a reduction gear connected to the one shaft portion and reducing the rotational speed of the shaft to output the reduced speed. The motor bracket has one or more external through-holes that penetrate in the axial direction radially outside the central through-hole, and the motor housing or the motor bracket has a cylindrical cover portion that covers the radially outer side of the opening on one side in the axial direction of all the external through-holes over the entire circumference, and the end face on one side in the axial direction of the cover portion is in contact with the case member of the reduction gear via a sealing member over the entire circumference and is sealed. [Effects of the Invention]

[0010] The electric vehicle drive system disclosed in this application comprises a motor body having a shaft, rotor, and stator; a motor housing to which the stator is fixed inside and which has an opening on one side in the axial direction; a motor bracket that covers one side in the axial direction of the stator and rotor and has a central through-hole through which one side of the shaft extending from the rotor in the axial direction passes; and a reduction gear connected to the one side of the shaft and outputting a reduced rotational speed of the shaft. The motor bracket has one or more outer through-holes that penetrate in the axial direction radially outside the central through-hole, and the motor housing or motor bracket has a cylindrical cover portion that covers the radially outside of the opening on one side in the axial direction of all the outer through-holes over the entire circumference, and the end face on one side in the axial direction of the cover portion abuts against the case member of the reduction gear via a sealing member over the entire circumference, so that it can be assembled to the reduction gear as a motor unit, compared to Patent Document 2, and the assembly and productivity of the electric vehicle drive system can be improved. Furthermore, since it is possible to inspect the motor unit as a unit, it is possible to grasp the variation of the motor unit as a unit, and thus the quality of the motor can be improved. Since the motor quality is improved, the reliability of the electric vehicle drive system can be ensured. Furthermore, compared to Patent Document 1, by providing an external through-hole in the motor bracket, the material cost of the electric vehicle drive system can be reduced, and the electric vehicle drive system can be made lighter. In addition, since the sealing is done during assembly rather than after sealing the motor and reduction gear separately, the sealing structure is simpler, and the electric vehicle drive system can be made smaller. [Brief explanation of the drawing]

[0011] [Figure 1] This is a cross-sectional view showing a schematic of the electric vehicle drive system according to Embodiment 1. [Figure 2] This is a schematic plan view showing the motor bracket of the electric vehicle drive system according to Embodiment 1. [Figure 3] This is a schematic cross-sectional view showing another electric vehicle drive system according to Embodiment 1. [Figure 4] This is a cross-sectional view showing an outline of the electric vehicle drive system according to Embodiment 2. [Modes for carrying out the invention]

[0012] The electric vehicle drive system according to the embodiment of the present application will be described below with reference to the drawings. In each drawing, the same or equivalent members and parts will be denoted by the same reference numerals.

[0013] Embodiment 1. Figure 1 is a schematic cross-sectional view of the electric vehicle drive unit 1 according to Embodiment 1, with details of the internal configuration omitted. Figure 2 is a schematic plan view of the motor bracket 7 of the electric vehicle drive unit 1, viewed from one side in the axial direction. The electric vehicle drive unit 1 mounted on an electric vehicle is a device that transmits the rotation of a motor 2 controlled by an inverter 3 connected to an external DC power source to the wheel axle of the electric vehicle via a reduction gear 4.

[0014] <Electric Vehicle Drive System 1> As shown in Figure 1, the electric vehicle drive unit 1 comprises a motor body 5 having a shaft 5a, a rotor 5b that rotates integrally with the shaft 5a, and a stator 5c that surrounds the rotor 5b from the radially outer side; a motor housing 6 to which the stator 5c is fixed inside and which has an opening on one side in the axial direction; a motor bracket 7 that covers one side in the axial direction of the stator 5c and rotor 5b and has a central through-hole 7a through which one side of the shaft portion 5a1 extending from the rotor 5b in the axial direction passes; and a reduction gear 4 connected to the one side of the shaft portion 5a1 that reduces the rotational speed of the shaft 5a and outputs the reduced speed. The motor 2 is composed of the motor body 5, motor housing 6, and motor bracket 7. The one side in the axial direction is the right side in the figure where the reduction gear 4 is positioned relative to the motor 2. The direction in which the motor housing 6 opens and the direction in which the shaft 5a of the rotor 5b fitted into the reduction gear 4 extends (the direction in which one side of the shaft portion 5a1 extends) are both on one side in the axial direction and coincide.

[0015] The electric vehicle drive unit 1 further includes an inverter 3 that converts DC power to AC power. The inverter 3 performs DC-AC conversion between a DC power source (not shown) and a multi-phase coil 5c2. In this embodiment, the inverter 3 is installed inside the case member 4a of the reduction gear 4. The portion of the case member 4a in which the inverter 3 is located is sealed by the inverter cover 3b via a sealing member 14. By installing the inverter 3 inside the case member 4a, the electric vehicle drive unit 1 can be miniaturized.

[0016] Furthermore, in this embodiment, the inverter 3 is housed in an inverter case 3a, and the inverter case 3a is integrated with the case member 4a of the reduction gear 4. This configuration reduces the number of parts that make up the case. As the number of parts is reduced, the cost of the electric vehicle drive system 1 can be reduced. By housing the inverter 3 in an inverter case 3a made of metal, noise leaking from the inverter 3 to the outside can be suppressed, and noise entering the inverter case 3a from the outside can be suppressed. In addition, if the case member 4a and the inverter case 3a are separate, when the case member 4a and the inverter case 3a are assembled, variations in placement may occur between the case member 4a and the inverter case 3a due to the assembly of the case member 4a and the inverter case 3a, but by integrating the inverter case 3a with the case member 4a of the reduction gear 4, variations in placement can be suppressed. The configuration is not limited to integrating the inverter case 3a with the case member 4a; as shown in Figure 3, the inverter 3 may be provided inside the case member 4a of the reduction gear 4 without providing an inverter case 3a. Figure 3 is a schematic cross-sectional view of another electric vehicle drive system 1 according to Embodiment 1. If an inverter case 3a is not provided, the area around the inverter 3 may be sealed with gel or the like to protect the inverter 3 from oil, etc., from the reduction gear 4.

[0017] As shown in FIG. 1, the stator 5c includes a cylindrical core 5c1, a coil 5c2 wound around the core 5c1, and two coil ends 5c3 that protrude from the core 5c1 and are ends of the coil 5c2 (only one is shown in the drawing). An end of the coil end 5c3 arranged on one axial side of the core 5c1 is provided with a terminal 8 to which phase power is supplied from the inverter 3. The shaft 5a is rotatably supported by bearings 9 and 10. The bearing 9 that supports the one-side shaft portion 5a1 extending from the rotor 5b to one axial side is provided adjacent to the central through hole 7a of the motor bracket 7. The bearing 10 that supports the other-side shaft portion 5a2 extending from the rotor 5b to the other axial side is provided on the motor housing 6. A shaft grounding member 11 that grounds the shaft 5a is provided on the other-side shaft portion 5a2 protruding from the motor housing 6 to the other axial side. The shaft grounding member 11 is a member installed as a countermeasure against shaft voltage. The shaft grounding member 11 slides between the shaft 5a and the grounded motor housing 6 to establish electrical conduction between the two. The shaft grounding member 11 is covered by a grounding cover 15. An oil seal 18 is provided in the through hole of the motor housing 6 through which the other-side shaft portion 5a2 penetrates.

[0018] As a speed reduction mechanism, the speed reducer 4 includes a plurality of gears, a gear shaft that is a shaft of the speed reducer 4 integrated with the gears and parallel to the axial direction of the motor 2, and a bearing that supports the gear shaft. The speed reducer 4 converts the rotation of the motor 2 and transmits it to the wheel shaft. In the present embodiment, the speed reducer 4 includes three gear shafts 4b, 4c, and 4d. The shaft 5a and the gear shaft 4b are arranged at the same axial position. The shaft 5a and the gear shaft 4b are connected by fitting, and transmit power to each other (the form of fitting is not shown). The gear shaft 4c is a shaft that rotates at a position different from that of the gear shaft 4b, and is decelerated from the gear shaft 4b by gear meshing to transmit power. The gear shaft 4d is a shaft that rotates at a position different from that of the gear shaft 4c, and is decelerated from the gear shaft 4c by gear meshing to transmit power.

[0019] A differential mechanism 12 is mounted on the gear shaft 4d. The differential mechanism 12 branches the output shaft and provides the function of absorbing the mutual rotational speed difference, so that the speed reduction mechanism can absorb the rotational speed difference between the left and right wheels when the vehicle is driven. The speed reduction mechanism is housed in the case member 4a of the speed reducer 4. In the present embodiment, the case member 4a is composed of a housing portion 4a1 having an opening on one side in the axial direction, and a lid portion 4a2 covering the opening of the housing portion 4a1. The lid portion 4a2 abuts against an end portion of the housing portion 4a1 provided substantially parallel to the rotation surface of the gear. The gear shafts 4b, 4c, and 4d are sandwiched between the housing portion 4a1 and the lid portion 4a2, and are rotatably supported by a bearing 19 provided at a bottom portion of the housing portion 4a1 and a bearing 20 provided on the lid portion 4a2. An oil seal 18 is provided in a through hole of the case member 4a through which the gear shaft 4d penetrates.

[0020] The motor housing 6, the motor bracket 7, and the case member 4a are produced by, for example, aluminum die casting. In the present embodiment, the motor housing 6 is formed in a bottomed cylindrical shape with an opening on one side in the axial direction. With this configuration, the motor housing 6 can be mass-produced at low cost by aluminum die casting or the like. Further, the number of parts can be reduced compared to a configuration in which the other axial side of the motor housing 6 is divided. In addition, since the motor 2 can be easily assembled by inserting the components of the motor main body 5 into the inside of the motor housing 6 through the opening of the motor housing 6, the assemblability and productivity of the electric vehicle drive device 1 can be improved.

[0021] <Seal Structure> The sealing structure, which is the main part of this application, will now be described. As shown in Figure 2, the motor bracket 7 has one or more outer through holes 7b that penetrate axially on the radially outer side of the central through hole 7a. In this embodiment, the motor bracket 7 has four outer through holes 7b, but the number of outer through holes 7b is not limited to four. As shown in Figure 1, the motor housing 6 or motor bracket 7 has a cylindrical cover portion 13 that covers the radially outer side of one axial opening of all outer through holes 7b around its entire circumference, and the axial end face of the cover portion 13 abuts against the case member 4a of the reduction gear 4 via a sealing member 14 around its entire circumference, thereby sealing it. In this embodiment, the motor bracket 7 abuts against the case member 4a, and the motor bracket 7 is fixed to the case member 4a.

[0022] The sealing member 14 is, for example, a liquid gasket, a metal gasket, or a rubber member such as an O-ring, but is not limited to these, and may be any other member. In the configuration of this application, the sealing member 14 is not limited in any way.

[0023] This configuration allows the motor 2 to be assembled to the reduction gear 4 as a standalone unit, compared to Patent Document 2, thereby improving the ease of assembly and productivity of the electric vehicle drive unit 1. Furthermore, since the motor 2 can be inspected as a standalone unit, variations in the motor 2 can be identified, improving the quality of the motor 2 and reducing the inspection costs for the motor 2. As the quality of the motor 2 improves, the reliability of the electric vehicle drive unit 1 can be ensured. In addition, compared to Patent Document 1, by providing an external through-hole 7b in the motor bracket 7, the material cost of the electric vehicle drive unit 1 can be reduced, and the electric vehicle drive unit 1 can be made lighter. Moreover, since the motor 2 and reduction gear 4 are sealed during assembly rather than being sealed separately before assembly, the sealing structure is simpler, allowing the electric vehicle drive unit 1 to be made smaller.

[0024] The details of the sealing structure in this embodiment will now be described. The motor bracket 7 covers the opening on one axial side of the motor housing 6. The motor bracket 7 has a cylindrical bracket extension 7c that extends axially from the portion where the central through hole 7a and the outer through hole 7b are provided, and the bracket extension 7c is the covering portion 13. With this configuration, the motor housing 6 can be manufactured in a simple bottomed cylindrical shape. Because the shape of the motor housing 6 is simple, the cost of the motor housing 6 can be reduced.

[0025] In this embodiment, the space between the axial opening of the motor housing 6 and the motor bracket 7 is sealed by a sealing member 14. The motor housing 6 is fixed to the motor bracket 7. This configuration allows for easy protection of the inside of the motor housing 6 from the outside. Furthermore, a case through-hole 4a3 is provided in the case member 4a of the reduction gear 4, which is surrounded by the cover portion 13, through which either the shaft portion 5a1 on one side or the gear shaft 4b, which is the shaft of the reduction gear 4 to which the shaft portion 5a1 is connected, passes. This configuration allows for easy connection of the shaft portion 5a1 on one side and the gear shaft 4b via the case through-hole 4a3. In addition, since the case through-hole 4a3 is covered by the cover portion 13, the case through-hole 4a3 can be sealed from the outside. Moreover, in this embodiment, since the inverter case 3a is integrated with the case member 4a of the reduction gear 4, the accuracy of the flatness of the portion of the case member 4a that the motor bracket 7 abuts is improved, thereby improving the sealing performance.

[0026] <Wiring structure> The wiring structure of this invention will now be described. An inverter through-hole 4a4 is provided in the case member 4a of the reduction gear 4, which is surrounded by the cover portion 13, and penetrates in the axial direction. The inverter 3 and the motor body 5 are connected via the outer through-hole 7b and the inverter through-hole 4a4. The motor body 5 has multiple points of connection to the inverter 3. Therefore, various connection lines such as phase power lines 3c and sensor signal lines 3d are arranged between the motor body 5 and the inverter 3. With this configuration, various connection lines can be easily connected to the motor body 5 and the inverter 3 via the outer through-hole 7b and the inverter through-hole 4a4. In addition, the end face of the cover portion 13 abuts against the case member 4a of the reduction gear 4 via the sealing member 14, and the inverter through-hole 4a4 is covered by the cover portion 13, so the inverter through-hole 4a4 can be sealed without providing an additional sealing structure. Since there is no need to provide an additional sealing structure, the productivity of the electric vehicle drive unit 1 can be improved.

[0027] In this embodiment, the end of the coil end 5c3, located on one axial side of the core 5c1, has a terminal 8 to which phase power is supplied from the inverter 3. The terminal 8 and the inverter 3 are connected via an outer through-hole 7b and an inverter through-hole 4a4. The inverter 3 has a phase power line 3c that supplies phase power from the inverter 3 to the terminal 8. The phase power line 3c passes through the outer through-hole 7b and the inverter through-hole 4a4. With this configuration, the terminal 8 and the inverter 3 can be connected via the outer through-hole 7b and the inverter through-hole 4a4 using the phase power line 3c, making it easy to connect the terminal 8 and the inverter 3. Furthermore, the length of the phase power line 3c, which is the wiring connecting the terminal 8 and the inverter 3, can be shortened. Since the length of the phase power line 3c is shortened, the influence of noise can be reduced.

[0028] In this embodiment, the motor body 5 has a temperature sensor 16. The temperature sensor 16 measures the temperature of the coil 5c2. The temperature sensor 16 is, for example, a thermistor. The inverter 3 controls the operation of the motor 2 using the temperature information measured by the temperature sensor 16. The temperature sensor 16 is attached to a coil end 5c3 located on one axial side of the core 5c1, and the temperature sensor 16 and the inverter 3 are connected via an outer through-hole 7b and an inverter through-hole 4a4. The inverter 3 has a sensor signal line 3d that connects the inverter 3 to the temperature sensor 16. The sensor signal line 3d passes through the outer through-hole 7b and the inverter through-hole 4a4. With this configuration, the temperature sensor 16 and the inverter 3 can be connected via the sensor signal line 3d through the outer through-hole 7b and the inverter through-hole 4a4, so the temperature sensor 16 and the inverter 3 can be easily connected without being affected by other components. In addition, the length of the sensor signal line 3d, which is the wiring connecting the temperature sensor 16 and the inverter 3, can be shortened. Since the length of the sensor signal line 3d is shortened, the effects of noise can be reduced.

[0029] In this embodiment, the motor body 5 has a rotation sensor 17. The rotation sensor 17 detects the rotation (rotation angle and rotation speed) of the motor body 5. The inverter 3 controls the operation of the motor 2 using the rotation information of the motor body 5 measured by the rotation sensor 17. The rotation sensor 17 is, for example, a resolver. The rotation sensor 17 is not limited to a resolver, but may also be a magnetic sensor using a magnetoelectric conversion element such as a Hall element. The rotation sensor 17 is attached to the motor bracket 7 inside the cover 13. The rotation sensor 17 and the inverter 3 are connected via an inverter through-hole 4a4. The inverter 3 has a sensor signal line 3d that connects the inverter 3 to the rotation sensor 17. The sensor signal line 3d passes through the inverter through-hole 4a4. With this configuration, the rotation sensor 17 and the inverter 3 can be connected via the inverter through-hole 4a4 and the sensor signal line 3d, so the rotation sensor 17 and the inverter 3 can be easily connected without being affected by other components. Furthermore, the length of the sensor signal line 3d, which connects the rotation sensor 17 and the inverter 3, can be shortened. Since the length of the sensor signal line 3d is shortened, the effects of noise can be reduced.

[0030] In this embodiment, the rotation sensor 17 is provided on one axial side of the motor bracket 7, and the motor bracket 7 is made of metal. The material of the motor bracket 7 is, for example, aluminum. The motor bracket 7 is grounded. With this configuration, a conductive motor bracket 7 is interposed between the stator 5c and the rotation sensor 17, thereby reducing the adverse effect of leakage magnetic flux generated from the stator 5c mixing into the rotation sensor 17 and causing noise. In this embodiment, an example in which the rotation sensor 17 is provided on one axial side of the motor bracket 7 is shown, but the arrangement of the rotation sensor 17 is not limited to this, and the rotation sensor 17 may be provided on the other axial side of the motor bracket 7. When the rotation sensor 17 is provided on the other axial side of the motor bracket 7, the rotation sensor 17 and the inverter 3 are connected by a sensor signal line 3d via an outer through hole 7b and an inverter through hole 4a4. When the rotation sensor 17 is provided on the other axial side of the motor bracket 7, it is desirable to cover the area around the rotation sensor 17 with a magnetic shield.

[0031] As described above, the electric vehicle drive device 1 according to Embodiment 1 comprises a motor body 5 having a shaft 5a, a rotor 5b, and a stator 5c; a motor housing 6 in which the stator 5c is fixed to the inside and which has an opening on one side in the axial direction; a motor bracket 7 that covers one side in the axial direction of the stator 5c and rotor 5b and has a central through hole 7a through which one side shaft portion 5a1 extending from the rotor 5b to one side in the axial direction passes; and a reduction gear 4 connected to one side shaft portion 5a1 that reduces the rotational speed of the shaft 5a and outputs the result. The motor bracket 7 is central The motor housing 6 or motor bracket 7 has one or more outer through holes 7b that penetrate axially on the radially outer side of the core through hole 7a, and the motor housing 6 or motor bracket 7 has a cylindrical cover portion 13 that covers the radially outer side of one axial opening of all outer through holes 7b around its entire circumference, and the axial end face of the cover portion 13 abuts against the case member 4a of the reduction gear 4 via a sealing member 14 around its entire circumference and is sealed. Compared to Patent Document 2, the motor 2 can be assembled to the reduction gear 4 as a standalone unit, thus improving the ease of assembly and productivity of the electric vehicle drive unit 1. In addition, since the motor 2 can be inspected as a standalone unit, variations in the motor 2 can be grasped, thereby improving the quality of the motor 2. As the quality of the motor 2 is improved, the reliability of the electric vehicle drive unit 1 can be ensured.

[0032] Furthermore, compared to Patent Document 1, by providing an external through-hole 7b in the motor bracket 7, the material cost of the electric vehicle drive unit 1 can be reduced, and the electric vehicle drive unit 1 can be made lighter. In addition, since the motor 2 and the reduction gear 4 are sealed during assembly rather than being assembled after each of them is sealed, the sealing structure is simpler, and the electric vehicle drive unit 1 can be made smaller.

[0033] If the motor bracket 7 covers one axial opening of the motor housing 6, and the motor bracket 7 has a cylindrical bracket extension 7c that extends axially from the portion where the central through hole 7a and outer through hole 7b are provided, and the bracket extension 7c is the covering portion 13, then the motor housing 6 can be manufactured in a simple bottomed cylindrical shape. Because the shape of the motor housing 6 is simple, the cost of the motor housing 6 can be reduced. Also, if the space between the axial opening of the motor housing 6 and the motor bracket 7 is sealed by a sealing member, the inside of the motor housing 6 can be easily protected from the outside.

[0034] If a case through-hole 4a3 is provided in the case member 4a of the reduction gear 4, which is surrounded by the cover portion 13, through which one side shaft portion 5a1 or the gear shaft 4b, which is the shaft of the reduction gear 4 to which one side shaft portion 5a1 is connected, then the one side shaft portion 5a1 and the gear shaft 4b can be easily connected via the case through-hole 4a3. Furthermore, since the case through-hole 4a3 is covered by the cover portion 13, the case through-hole 4a3 can be sealed from the outside.

[0035] In the electric vehicle drive system 1, an inverter 3 is provided for converting DC power to AC power. The inverter 3 is located inside the case member 4a of the reduction gear 4. An inverter through-hole 4a4 is provided in the portion of the case member 4a of the reduction gear 4 that is surrounded by a cover portion 13, and the inverter 3 and the motor body 5 are connected via an outer through-hole 7b and an inverter through-hole 4a4. Various connection lines, such as phase power lines 3c and sensor signal lines 3d, can be easily connected via the outer through-hole 7b and the inverter through-hole 4a4. Furthermore, the end face of the cover portion 13 abuts against the case member 4a of the reduction gear 4 via a sealing member 14, and the inverter through-hole 4a4 is covered by the cover portion 13. Therefore, the inverter through-hole 4a4 can be sealed without providing an additional sealing structure. Since there is no need to provide an additional sealing structure, the productivity of the electric vehicle drive system 1 can be improved.

[0036] When the inverter 3 is housed in the inverter case 3a, and the inverter case 3a is integrated with the case member 4a of the reduction gear 4, the number of parts forming the case can be reduced. Since the number of parts is reduced, the cost of the electric vehicle drive system 1 can be reduced. In addition, when the case member 4a and the inverter case 3a are separate, when the case member 4a and the inverter case 3a are assembled, variations in placement may occur between the case member 4a and the inverter case 3a due to the assembly of the case member 4a and the inverter case 3a. However, by integrating the inverter case 3a with the case member 4a of the reduction gear 4, variations in placement can be suppressed.

[0037] The stator 5c has a cylindrical core 5c1, a coil 5c2 wound around the core 5c1, and two coil ends 5c3 protruding from the core 5c1, which are the ends of the coil 5c2. The ends of the coil ends 5c3, which are located on one axial side of the core 5c1, have terminals 8 to which phase power is supplied from the inverter 3. If the terminals 8 and the inverter 3 are connected via an outer through-hole 7b and an inverter through-hole 4a4, then the terminals 8 and the inverter 3 can be connected via the outer through-hole 7b and the inverter through-hole 4a4 using phase power lines 3c, thus making it easy to connect the terminals 8 and the inverter 3. Furthermore, the length of the phase power lines 3c, which are the wiring connecting the terminals 8 and the inverter 3, can be shortened.

[0038] The temperature sensor 16 is attached to the coil end 5c3 located on one axial side of the core 5c1, and the temperature sensor 16 and stomach Nbata 3 When the two components are connected via the outer through-hole 7b and the inverter through-hole 4a4, the temperature sensor 16 and the inverter 3 can be connected via the outer through-hole 7b and the inverter through-hole 4a4 using the sensor signal line 3d, allowing for easy connection of the temperature sensor 16 and the inverter 3 without being affected by other components. Furthermore, the length of the sensor signal line 3d, which is the wiring connecting the temperature sensor 16 and the inverter 3, can be shortened.

[0039] When the rotation sensor 17, which detects the rotation of the motor body 5, is mounted on the motor bracket 7 inside the cover 13, and the rotation sensor 17 and the inverter 3 are connected via the inverter through-hole 4a4, the rotation sensor 17 and the inverter 3 can be connected via the inverter through-hole 4a4 using a sensor signal line 3d. This allows for easy connection of the rotation sensor 17 and the inverter 3 without being affected by other components. Furthermore, the length of the sensor signal line 3d, which connects the rotation sensor 17 and the inverter 3, can be shortened.

[0040] Rotating sensor 17 However, if the motor bracket 7 is provided on one side in the axial direction and the motor bracket 7 is made of metal, the conductive motor bracket 7 is interposed between the stator 5c and the rotation sensor 17, thereby reducing the adverse effect of leakage magnetic flux generated from the stator 5c mixing into the rotation sensor 17 and causing noise. Furthermore, if the motor housing 6 is formed in a closed-bottom cylindrical shape with one side in the axial direction open, the motor housing 6 can be mass-produced inexpensively using aluminum die casting or the like. In addition, since the motor 2 can be easily assembled by inserting the components of the motor body 5 into the inside of the motor housing 6 through the opening, the ease of assembly and productivity of the electric vehicle drive unit 1 can be improved.

[0041] Embodiment 2. The electric vehicle drive unit 1 according to Embodiment 2 will now be described. Figure 4 is a schematic cross-sectional view of the electric vehicle drive unit 1 according to Embodiment 2, and details of the internal configuration are omitted. In the electric vehicle drive unit 1 according to Embodiment 2, the motor housing 6 abuts against the case member 4a via a sealing member 14, and the motor housing 6 is fixed to the case member 4a.

[0042] In this embodiment, the motor housing 6 has a cylindrical housing extension 6a that extends radially outward from the motor bracket 7 to one side in the axial direction. The motor bracket 7 is positioned inside the housing extension 6a, and the portion of the housing extension 6a on one side in the axial direction relative to the motor bracket 7 is the cover portion 13.

[0043] This configuration eliminates the need for a sealing member between the motor bracket 7 and the motor housing 6, thereby improving the ease of assembly and productivity of the electric vehicle drive unit 1. Furthermore, it allows for a reduction in the cost of the electric vehicle drive unit 1.

[0044] The diagram of motor 2 shown in this application depicts a commonly used inner rotor / radial gap type configuration. However, the configuration of motor 2 is not limited to this, and other forms are also possible, such as outer rotor / radial gap type, axial gap type, or other motor types. The configuration of this application is applicable to motors with other configurations, and there is no intention to limit the motor configuration.

[0045] Furthermore, although this application describes various exemplary embodiments and examples, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but can be applied individually or in various combinations to the embodiments. Accordingly, countless variations not illustrated are conceivable within the scope of the technology disclosed herein. These include, for example, modifications, additions, or omissions of at least one component, as well as the extraction of at least one component and its combination with components of other embodiments. [Explanation of Symbols]

[0046] 1 Electric vehicle drive unit, 2 Motor, 3 Inverter, 3a Inverter case, 3b Inverter cover, 3c Phase power line, 3d Sensor signal line, 4 Reducer, 4a Case member, 4a1 Housing section, 4a2 Cover, 4a3 Case through hole, 4a4 Inverter through hole, 4b, 4c, 4d Gear shaft, 5 Motor body, 5a Shaft, 5a1 One side of the shaft, 5a2 The other side of the shaft, 5b Rotor, 5c Stator, 5c1 Core, 5c2 Coil, 5c3 Coil end, 6 Motor housing, 6a One side extension of the housing, 7 Motor bracket, 7a Center through hole, 7b Outer through hole, 7c One side extension of the bracket, 8 Terminal, 9 Bearing, 10 Bearing, 11 Shaft grounding member, 12 Differential mechanism, 13 Cover, 14 Seal member, 15 Grounding cover, 16 Temperature sensor, 17. Rotation sensor, 18. Oil seal, 19. Bearings

Claims

1. A motor body having a shaft, a rotor that rotates integrally with the shaft, and a stator that surrounds the rotor from the radially outer side, The stator is fixed to the inside of the motor housing, which has an opening on one side in the axial direction, A motor bracket that covers one axial side of the stator and the rotor, and has a central through-hole through which one shaft portion extending axially from the rotor passes; The system includes a reduction gear connected to the shaft portion on one side, which reduces the rotational speed of the shaft and outputs the result, The motor bracket has one or more outer through holes that penetrate axially, located radially outside the central through hole. The motor housing or motor bracket has a cylindrical covering portion that covers the radially outer side of one axial opening of all the outer through holes around its entire circumference. The end face on one axial side of the cover portion is in contact with the case member of the reduction gear via a sealing member over its entire circumference, thereby sealing the electric vehicle drive device.

2. The motor housing has a cylindrical housing extension that extends radially outward from the motor bracket to one side in the axial direction, The motor bracket is positioned inside the one-sided extension of the housing, The electric vehicle drive device according to claim 1, wherein the portion of the housing extension on one side that is on one side in the axial direction from the motor bracket is the covering portion.

3. The motor bracket covers the opening on one axial side of the motor housing. The motor bracket has a cylindrical bracket extension that extends axially to one side from the portion where the central through hole and the outer through hole are provided, The electric vehicle drive device according to claim 1, wherein the bracket extension on one side is the covering portion.

4. The electric vehicle drive device according to claim 3, wherein the space between the opening on one axial side of the motor housing and the motor bracket is sealed by a sealing member.

5. The electric vehicle drive device according to any one of claims 1 to 4, wherein the case member of the reduction gear surrounded by the cover is provided with a case through-hole through which the shaft portion on one side or the shaft of the reduction gear to which the shaft portion on one side is connected passes.

6. Equipped with an inverter that converts DC power to AC power, The inverter is provided inside the case member of the reduction gear, An inverter through-hole is provided in the portion of the case member of the reduction gear surrounded by the aforementioned cover portion, The electric vehicle drive device according to claim 1, wherein the inverter and the motor body are connected via the outer through-hole and the inverter through-hole.

7. The inverter is housed in an inverter case, The electric vehicle drive device according to claim 6, wherein the inverter case is integrated with the case member of the reduction gear.

8. The stator comprises a cylindrical core, a coil wound around the core, and two coil ends protruding from the core, which are the ends of the coil. The end of the coil end, located on one side of the core in the axial direction, has a terminal to which phase power is supplied from the inverter. The electric vehicle drive device according to claim 6, wherein the terminal and the inverter are connected via the outer through-hole and the inverter through-hole.

9. The stator comprises a cylindrical core, a coil wound around the core, and two coil ends protruding from the core, which are the ends of the coil. A temperature sensor is attached to the coil end located on one side of the core in the axial direction. The electric vehicle drive device according to claim 6, wherein the temperature sensor and the inverter are connected via the outer through-hole and the inverter through-hole.

10. A rotation sensor for detecting the rotation of the motor body is attached to the motor bracket portion inside the cover portion. The electric vehicle drive device according to claim 6, wherein the rotation sensor and the inverter are connected via the inverter through-hole.

11. The rotation sensor is provided on one side of the motor bracket in the axial direction. The motor bracket is made of metal, as described in claim 10.

12. The electric vehicle drive device according to claim 1, wherein the motor housing is formed in the shape of a bottomed cylindrical shape with one side in the axial direction open.

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