Drive device

Description

1 / 25 “DRIVE DEVICE” TECHNICAL FIELD

[001] The technique disclosed in this document refers to a drive device. BACKGROUND OF THE INVENTION REFERENCE TO RELATED DEPOSIT REQUEST(S)

[002] This application is a related application and claims priority to Japanese patent application No. 2023-45413 filed on March 22, 2023. The full content of the priority application is incorporated herein by reference.

[003] Japanese patent application publication No. 2020-40578 discloses a drive device comprising a motor and an electric motor control device configured to control the motor. The electric motor control device is disposed above the motor. SUMMARY OF THE INVENTION

[004] There are many parts that need to be installed in a limited space in the vehicle. Efficient use of such space has been required for the installation of these parts.

[005] These teachings provide a technology that enables the effective use of space.

[006] A first aspect disclosed in the present document relates to a drive device. The drive device may comprise: a motor comprising a motor shaft; a first gear configured to rotate around a central geometric axis of the motor shaft; and an inverter comprising a plurality of components configured to be used to control the motor, wherein at least one part of the inverter may overlap the motor in a central geometric axis direction, and at least one part of the inverter may overlap the first gear in a radial direction of the first gear. Petition 870250084702, dated 09 / 19 / 2025, page 10 / 49 2 / 25 gear.

[007] In this configuration, the inverter is positioned in a space around the motor shaft created by a difference in dimensions between the motor and the first gear. This allows for efficient use of the space around the motor shaft.

[008] Further details and enhancements of the technology disclosed in this document are described in the DETAILED DESCRIPTION below. BRIEF DESCRIPTION OF THE DRAWINGS

[009] [Figure 1] A side view of an electric vehicle on / above which a drive unit, according to one embodiment, is mounted.

[010] [Figure 2] A side view of the drive unit with one housing removed.

[011] [Figure 3] A schematic internal structure of the drive unit.

[012] [Figure 4] A plan view of the drive unit.

[013] [Figure 5] A bottom view of the drive unit.

[014] [Figure 6] A side view of the drive unit to explain a bus unit configuration.

[015] [Figure 7] A perspective view of the busbar unit.

[016] [Figure 8] A perspective view of the busbar unit.

[017] [Figure 9] A block diagram of a cooling circuit configuration. DESCRIPTION OF MODALITIES

[018] In a second aspect disclosed in the present document, in the first aspect described above, the plurality of components may comprise: a power module comprising a plurality of switching elements; a filtering capacitor; and a noise filter, and the power module, the filtering capacitor, and the noise filter may be arranged in that order, on an upper side Petition 870250084702, dated 09 / 19 / 2025, page 11 / 49 3 / 25 towards a lower side.

[019] According to this configuration, by placing the battery near a lower end of the inverter, the wiring can be shortened when battery power is supplied to the noise filter, the filtering capacitor and the power module, in that order.

[020] In a third aspect disclosed in the present document, in the second aspect described above, a length of each of the power module, the filter capacitor and the noise filter along a direction of rotation of the first gear may be longer than a length of each of the power module, the filter capacitor and the noise filter along the radial direction of the first gear, and a range, in the direction of rotation of the first gear, from an end opposite the filter capacitor of the power module to an end opposite the filter capacitor of the noise filter, may be 180° or more around the central geometric axis.

[021] In this configuration, the respective longitudinal directions of the power module, the filter capacitor, and the noise filter are arranged along the direction of rotation of the first gear. This makes it possible to use the space around the first gear effectively.

[022] In a fourth aspect disclosed in this document, in the second or third aspect described above, the drive device may further comprise a second gear configured to mesh with the first gear, wherein the first gear may be disposed between the second gear and the power module.

[023] The power module is a relatively large component among the various components of the inverter. By arranging the power module on the opposite side of the second gear with the first gear interposed between the power module and the second gear, the power module and the Petition 870250084702, dated 09 / 19 / 2025, page 12 / 49 4 / 25 second gear can be arranged in an efficient layout.

[024] In a fifth aspect revealed in this document, in the fourth aspect described above, the second gear may be arranged below the first gear and the power module.

[025] In this configuration, the motor torque is transmitted down from the first gear to the second gear. According to this configuration, the motor can be positioned above the drive shaft. This eliminates the need to significantly alter the motor's position relative to the drive shaft, while still arranging the power module and the second gear in an efficient position.

[026] In a sixth aspect disclosed in this document, in any one of the first to fifth aspects described above, the drive device may further comprise: a plurality of shafts including the motor shaft and a drive shaft; and one or more gears arranged on each of the plurality of shafts, wherein the one or more gears arranged on the motor shaft may include the first gear.

[027] According to this configuration, the motor torque can be transmitted to the drive shaft through multiple gears.

[028] In a seventh aspect revealed in the present document, in the sixth aspect described above, an outside diameter of the first gear may be the smaller of one or more outside diameters of one or more gears.

[029] According to this configuration, by arranging multiple inverter components around the first gear, the smallest of the multiple gears of the motor on a shaft, space can be used effectively. (Modality)

[030] Figure 1 shows a schematic side view of a front portion of an electric vehicle 2 in which a drive unit 10, according to a Petition 870250084702, dated 09 / 19 / 2025, page 13 / 49 5 / 25 modality, is assembled. Electric vehicle 2 includes, in addition to the drive unit 10, a body 4, a battery 6, a suspension element 8, and a pair of front wheels 100. A plurality of devices for operating electric vehicle 2, such as a pair of rear wheels, a control device, etc., are mounted on electric vehicle 2, although they are not shown. In Figure 1, components other than the drive unit 10 and the suspension element 8 are represented by dashed lines for ease of understanding. Furthermore, to facilitate visualization of the drawing, the outlines of the components are shown in a simplified form. Electric vehicle 2 comprises any vehicle that uses an electric motor for at least part of its traction, such as a hybrid vehicle, a fuel cell vehicle, etc., as well as an electric vehicle.From now on, “up”, “down”, “left”, “right”, “forward” and “backward” are based on the direction indicators in the drawings (Drive unit configuration).

[031] The drive unit 10 is located in front of a front seat (not shown) of the electric vehicle 2. The drive unit 10 is located in a compartment located in front of a cabin space in which passengers travel in the electric vehicle 2. The drive unit 10 is located between the pair of front wheels 100 located at the respective ends of the electric vehicle 2 in a left-to-right direction. The drive unit 10 is located behind the front trunk 9, which is located near the front end of the electric vehicle 2. The front trunk 9 is a space that is separate from the cabin space and can accommodate luggage in it. The drive unit 10 is located in front of the vehicle center C of the electric vehicle 2 in a front-to-back direction.

[032] The drive unit 10 is attached to the suspension element 8. The suspension element 8 is part of a suspension unit (not shown) including springs, shock absorbers, etc. arranged for the respective front wheels. Petition 870250084702, dated 09 / 19 / 2025, page 14 / 49 6 / 25 100. Suspension element 8 supports the springs, shock absorbers, etc. In this way, the suspension unit is mounted on the electric vehicle 2.

[033] The drive unit 10 is protected by an enclosure 12. Figure 2 shows a right side view of the inside of the enclosure 12 with a right wall of the enclosure 12 removed. The drive unit 10 includes, unlike the enclosure 12, a motor 14, a gear unit 30, an inverter 20 and a drive shaft 90.

[034] Enclosure 12 houses motor 14, gear unit 30, inverter 20 and drive shaft 90. Enclosure 12 defines a housing space in which multiple components are mounted together.

[035] In drive unit 10, inverter 20 converts DC power from battery 6 into AC power suitable for powering motor 14. Battery 6 is located below a floor panel (not shown) of electric vehicle 2. Battery 6 supplies electrical power to drive unit 10. Drive unit 10 thus drives the pair of front wheels 100. In addition, drive unit 10 also functions as an electricity generator. Battery 6 stores electrical power supplied by drive unit 10.

[036] Inverter 20 supplies AC power to motor 14. Motor 14 is driven with AC power from inverter 20. The torque from motor 14 is transmitted to drive shaft 90 via gear unit 30. Drive shaft 90 transmits the torque from motor 14 to each of the front wheels 100 to rotate the pair of front wheels 100. In this way, electric vehicle 2 is driven. Inverter 20 converts AC power generated by motor 14 into DC power and supplies it to battery 6.

[037] The motor 14 is located in an upper rear portion of the drive unit 10. Figure 3 shows an internal structure of the drive unit 10 as viewed from a lower front portion towards the rear portion. Petition 870250084702, dated 09 / 19 / 2025, page 15 / 49 7 / 25 top rear. In Figure 3, the representation of the inverter 20 is partially omitted for illustration of the gear unit 30. The motor 14 includes a body 14a, a rotor 14c, and a stator 14d, and a motor shaft 14b extending from the rotor 14c. The stator 14d has a cylindrical shape. The stator 14d includes a stator core including a plurality of teeth and coils arranged on the plurality of teeth, although these are not shown. The rotor 14c is situated within the stator 14d. The outer circumferential surface of the rotor 14c faces the inner circumferential surface of the stator 14d. The rotor 14c includes a plurality of permanent magnets on its outer circumferential surface, which are arranged so that the polarities alternate in the circumferential direction of the rotor 14c. When AC power from inverter 20 is supplied to each stator coil 14d, a magnetic field generated in stator 14d changes. In this way, rotor 14c rotates.The motor shaft 14b is coaxial with the center of rotation of the rotor 14c. The motor shaft 14b extends linearly from the body 14a to the right. (Gear unit configuration)

[038] The torque generated by motor 14 is transmitted to the gear unit 30 via the motor shaft 14b. The gear unit 30 includes a shaft gear 32, a countershaft gear 34, a countershaft gear 42, a crown gear 50, a differential gear 52, and a shaft 44. Each of the shaft gear 32, the countershaft gear 34, the countershaft gear 42, and the crown gear 50 has a cylindrical shape with a plurality of teeth arranged on its circumferential surface. The teeth of the shaft gear 32, the countershaft gear 34, the countershaft gear 42, and the crown gear 50 are not shown. The shaft gear 32 is fixed to the motor shaft 14b. The motor shaft 14b is supported by bearings 36, 38 fixed to the housing 12 so that it rotates relative to the housing 12. The gear unit 30 makes direct contact with the motor 14 in the drive unit 10, which enables the Petition 870250084702, dated 09 / 19 / 2025, page 16 / 49 The 8 / 25 gear unit 30 and the motor 14 are mechanically connected to each other easily.

[039] The countershaft gear 34 engages the shaft gear 32 and rotates as the shaft gear 32 rotates. The countershaft gear 34 is located below and in front of the shaft gear 32. The countershaft gear 34 is fixed to the shaft 44. The shaft 44 is parallel to the motor shaft 14b. The shaft 44 is located below and in front of the motor shaft 14b. The shaft 44 is supported by bearings 46, 48 fixed to the housing 12 so that it rotates relative to the housing 12. The countershaft gear 42 is fixed to the shaft 44. In this way, the countershaft gear 42 is coaxially coupled to the countershaft gear 34. The countershaft gear 42 rotates as the countershaft gear 34 rotates. Crown gear 50 engages countershaft gear 42 and rotates as countershaft gear 42 rotates.

[040] The crown gear 50 is located below and in front of the countershaft gear 42. The crown gear 50 rotates around a central geometric axis Y (see Figure 2). The crown gear 50 is fixed to the differential gear 52. The differential gear 52 rotates as the crown gear 50 rotates. The differential gear 52 is a gear mechanism that rotates the pair of front wheels 100 independently by the rotation of the crown gear 50. The differential gear 52 is located below and in front of the crown gear 50. The differential gear 52 drives the drive shaft 90. The drive shaft 90 is located below and in front of the shaft 44. When the rotation of the motor 14 is transmitted to the drive shaft 90, the drive shaft 90 rotates around the central geometric axis Y and the pair of front wheels 100 rotate around the drive shaft 90. In this way, the electric vehicle 2 moves.

[041] As described, the countershaft gear 34 is located below and in front of the shaft gear 32. The countershaft gear 42 is coaxial with the countershaft gear 34, that is, they are aligned side by side in the direction Petition 870250084702, dated 09 / 19 / 2025, page 17 / 49 9 / 25 left-right. The crown gear 50 is located below and in front of the countershaft gear 42. The differential gear 52 is located below and in front of the crown gear 50. In other words, the differential gear 52, the crown gear 50, the countershaft gears 42, 34, and the axle gear 32 are arranged in that order, from the lower front to the upper rear. Thus, as shown in Figure 1, an upper surface 12a and a lower surface 12b of the housing 12 in which the gear unit 30 is housed are inclined upwards from the front towards the rear, that is, towards the center C of the vehicle.

[042] A central geometric axis X of the motor shaft 14b (i.e., central geometric axis X of the shaft gear 32) is parallel to the central geometric axis Y of the crown gear 50. As shown in Figure 2, most of the countershaft gear 34 is situated below a plane P that connects the central geometric axis X of the motor shaft 14b and the central geometric axis Y of the crown gear 50. The countershaft gear 42 is entirely situated below plane P. In a variant, the countershaft gear 34 may be entirely situated below plane P. This configuration ensures space above the gear unit 30. In this way, a device such as the inverter 20, etc., can be disposed above the gear unit 30.

[043] The outer diameter of the countershaft gear 34 (that is, the diameter of a circle defined by connecting points of the teeth arranged on the outer circumference) is larger than the outer diameter of the shaft gear 32. The outer diameter of the crown gear 50 is larger than the outer diameter of the countershaft gear 42. Thus, the rotational speed of the shaft gear 32 is reduced by two steps. Among the multiple gears 32, 34, 42, 50 of the gear unit 30, the shaft gear 32 has the smallest outer diameter. In a variant, the gear unit 30 may include a gear that is as large as or smaller than the shaft gear 32. Petition 870250084702, dated 09 / 19 / 2025, page 18 / 49 10 / 25 (Inverter Configuration)

[044] As shown in Figure 1, the inverter 20 is connected to battery 6 via a power cable 7. The inverter 20 converts DC power from battery 6 into AC power suitable for driving motor 14. The inverter 20 is a high-voltage component to which high-voltage power is applied. Here, “high voltage” means an operating voltage that is greater than 60 V DC and less than or equal to 1500 V, or an operating voltage that is greater than 30 V AC (rms value) and less than or equal to 1000 V (rms value). The inverter 20 also converts AC power from motor 14 into DC power suitable for battery 6. In one variant, the inverter 20 converts DC power into AC power, while it may not convert AC power into DC power.

[045] As shown in Figure 2, the inverter 20 includes a power module 22, a filtering capacitor 24, a noise filter 26, a connector 28 and bus units 60, 70 (see Figure 6). Energy from battery 6 is fed into the inverter 20 via connector 28, passes through noise filter 26, bus unit 60, filtering capacitor 24, power module 22 and bus unit 70 in that order, and is then supplied to motor 14 from bus unit 70.

[046] Connector 28 includes a terminal (not shown) connected to a power cable terminal 7 and a cover 28a surrounding the terminal. Connector 28 penetrates the enclosure 12, extending from the outside of the enclosure 12 to the inside. The terminal extends in a left-to-right direction and is connected to the power cable 7. As shown in Figure 2, the cover 28a projects downward and backward from the lower surface 12b of the enclosure 12. The cover 28a is situated in a space below the lower surface 12b. The cover 28a is situated below the rear end of the enclosure 12 and backward from the lowermost end of the enclosure 12.

[047] The terminal of connector 28 extends to the noise filter 26. The filter of Petition 870250084702, dated 09 / 19 / 2025, page 19 / 49 11 / 25 Noise 26 is an electromagnetic compatibility (EMC) noise filter. Noise filter 26 includes circuit components (not shown), such as a capacitor, a choke coil, etc., and a housing 26a that houses the circuit components. Noise filter 26 is housed in housing 12. Housing 26a is attached to an inner wall of housing 12. Noise filter 26 is situated above and in front of connector 28.

[048] The noise filter 26 is connected to the filtering capacitor 24 via the bus unit 60. The filtering capacitor 24 includes a capacitor (not shown) that absorbs voltage fluctuations and a housing 24a that houses the capacitor. The filtering capacitor 24 is housed in the housing 12. The housing 24a is attached to the inner wall of the housing 12. The filtering capacitor 24 is situated above the noise filter 26.

[049] The filtering capacitor 24 is connected to the power module 22 via a wire. The power module 22 converts DC power from battery 6 into AC power. The power module 22 supplies the converted AC power to the motor 14. The power module 22 includes multiple combinations of switching elements (not shown) to convert DC power into three-phase AC power and diodes (not shown). The power module 22 includes a housing 22a that houses the multiple combinations of switching elements and diodes. The power module 22 can convert the AC power supplied by the motor 14 generating electricity into DC power. The power module 22 is housed in the housing 12. The housing 22a is attached to the inner wall of the housing 12. The power module 22 is situated above and in front of the filtering capacitor 24. (Positional relationships between the motor, the gear unit, and the inverter)

[050] As shown in Figure 2, the power module 22, the filtering capacitor 24, and the noise filter 26 are arranged along the outer circumference of the shaft gear 32. As viewed in the left-to-right direction, that is, in the direction along the central geometric axis X of the motor shaft 14b, the module of Petition 870250084702, dated 09 / 19 / 2025, page 20 / 49 12 / 25 power module 22, filter capacitor 24, and noise filter 26 overlap motor 14. Specifically, the edges of the housing 22a of the power module 22, the housing 24a of the filter capacitor 24, and the housing 26a of the noise filter 26 do not partially overlap motor 14.

[051] As visualized in the direction along the central geometric axis X of motor shaft 14b, 99% of the area of ​​power module 22, 99% of the area of ​​filtering capacitor 24, and 99% of the area of ​​noise filter 26 overlap with motor 14. In a variant, as visualized in the direction along the central geometric axis X of motor shaft 14b, the entire area (i.e., 100%) of power module 22, the entire area of ​​filtering capacitor 24, and the entire area of ​​noise filter 26 may overlap with motor 14. At least one of the power module 22, the filtering capacitor 24, and the noise filter 26 may overlap with motor 14 along its entire area. Alternatively, as visualized in the direction along the central geometric axis X of motor shaft 14b, the power module 22, the filtering capacitor 24, and the noise filter 26 can overlap motor 14 in 50% to 100% of their areas.As visualized in the direction along the central geometric axis X of motor shaft 14b, the power module 22, the filtering capacitor 24, and the noise filter 26 can overlap the motor 14 in at least one of 60% to 100% of their areas, 70% to 100% of their areas, 80% to 100% of their areas, and 90% to 100% of their areas.

[052] The maximum length of the power module 22 in a rotation direction R of the shaft gear 32 is greater than the maximum length of the same in a radial direction of the shaft gear 32. Similarly, the maximum length of the filtering capacitor 24 in the rotation direction of the shaft gear 32 is greater than the maximum length of the same in a radial direction of the shaft gear 32. Similarly, the maximum length of the noise filter 26 in the rotation direction of the shaft gear 32 is greater than the maximum length of the same in a radial direction of the shaft gear 32. In other words, the module of Petition 870250084702, dated 09 / 19 / 2025, p. 21 / 49 13 / 25 power 22, the filtering capacitor 24 and the noise filter 26 are arranged so that their longitudinal directions are along the direction of rotation of the shaft gear 32 and their short directions are along radial directions of the shaft gear 32.

[053] In the direction of rotation of the shaft gear 32, an angle AN between an end 22b of the power module 22 facing the opposite direction to the filter capacitor 24 and an end 26b of the noise filter 26 facing the opposite direction to the filter capacitor 24 is greater than or equal to 240 degrees. The angle AN may be greater than or equal to 180 degrees.

[054] The shortest distances from the central geometric axis X to the power module 22, the filtering capacitor 24, and the noise filter 26 can be substantially equal. Furthermore, the filtering capacitor 24 and the noise filter 26 are each inclined in the direction of rotation R relative to the power module 22. That is, the power module 22, the filtering capacitor 24, and the noise filter 26 are arranged so that they intersect if extended along their longitudinal directions. (Bus unit configurations)

[055] With reference to Figures 6 to 8, bus units 60, 70 are described. In Figure 6, the inverter components 20, which are shown in the side view of the drive unit 10 in Figure 2, other than bus units 60, 70, are omitted. Bus unit 60 extends from noise filter 26 to filtering capacitor 24. In the left-to-right direction, bus unit 60 is situated between motor 14 and noise filter 26 and between motor 14 and filtering capacitor 24. Bus unit 60 includes two busbars 62, 64 and a cover 66. Busbars 62, 64 are made of a conductive material. The two busbars 62, 64 communicate electrically between the noise filter 26 and the filtering capacitor 24. Busbars 62, 64 include portions of Petition 870250084702, dated 09 / 19 / 2025, page 22 / 49 14 / 25 body 62a, 64a curves along the direction of rotation R of shaft gear 32, that is, along the outer circumference of motor 14, end portions 62b, 64b extending from body portions 62a, 64a in a bent shape relative to filter capacitor 24, and end portions 62c, 64c extending from body portions 62a, 64a in a bent shape relative to noise filter 26, respectively.

[056] End portions 62b, 64b are electrically connected to filter capacitor 24. End portions 62c, 64c are electrically connected to noise filter 26. Body portions 62a, 64a of busbars 62, 64 are covered by cover 66. Cover 66 is attached to the inner wall of the enclosure 12. Cover 66 is made of an insulating material such as a resin. Figure 8 illustrates a perspective view of cover 66 with a cap 66c (see Figure 6) removed. Cover 66 includes a cover portion 66a, a wall 66b, and the cap 66c.

[057] Cover portion 66a retains busbars 62, 64 covering body portions 62a, 64a. Cover portion 66a isolates body portions 62a, 64a from the outside of busbars 62, 64. Consistent with body portions 62a, 64a, cover portion 66a is curved along the direction of rotation R. Wall 66b is arranged on a face of cover portion 66a that is facing inverter 20. Wall 66b projects perpendicular to the face of cover portion 66a in a direction in which end portions 62b, 64b, 62c, 64c extend from the face of cover portion 66a. Wall 66b extends along the entire outer edge of the face of cover portion 66a. An opening defined by wall 66b opposite the cover portion 66a is closed by cover 66c. The interface between wall 66b and cover 66c is sealed by a liquid-impermeable sealing element.A passage 66d for a refrigerant is defined by the face of the cover portion 66a, wall 66b and cap 66c. The end portions 62b, 64b. Petition 870250084702, dated 09 / 19 / 2025, p. 23 / 49 15 / 25 are separated from passage 66d by a partition wall 66e that projects from the covering portion 66a. The end portions 62c, 64c are separated from passage 66d by a partition wall 66f that projects from the covering portion 66a.

[058] Passage 66d communicates with an inlet 66g at its upper end through a through hole defined in wall 66b. Inlet 66g is defined in a cylindrical portion 66h situated at an upper end of the cover portion 66a. Inlet 66g is situated in an upper end portion of the bus unit 60. Passage 66d communicates with an outlet 66j at its lower end through a through hole defined in wall 66b. Outlet 66j is defined in a cylindrical portion 66k situated at a lower end of the cover portion 66a. Outlet 66j is situated in a lower end portion of the bus unit 60. As shown in Figure 5, the cylindrical portion 66k is connected to a communication tube 12c disposed in the enclosure 12. The communication tube 12c is disposed on the lower surface 12b. Output 66j communicates with the outside of enclosure 12 via communication tube 12c.

[059] Busbar unit 70 extends from power module 22 to motor 14. As shown in Figure 7, busbar unit 70 includes three busbars 72, 74, 76 and a cover 78. Busbars 72, 74, 76 are made of the same conductive material as busbars 62, 64. Busbars 72, 74, 76 each extend in a left-to-right direction from a position ahead of power module 22 to a position ahead of and above motor 14. Busbars 72, 74, 76 correspond to three-phase AC phases. Busbars 72, 74, and 76 provide electrical communication between power module 22 and motor 14. Busbar 72 includes an end portion 72c in electrical contact with power module 22, an end portion 72b in electrical contact with motor 14, and a body portion 72a that extends between end portions 72b and 72c. Petition 870250084702, dated 09 / 19 / 2025, page 24 / 49 16 / 25 As with busbar 72, busbars 74 and 76 include end portions 74b and 76b, end portions 74c and 76c, and body portions 74a and 76a, respectively.

[060] End portions 72b, 74b, 76b are electrically connected to the stator 14d of the motor 14. End portions 72c, 74c, 76c are electrically connected to the power module 22. Body portions 72a, 74a, 76a are covered by a cover 78. The cover 78 is fixed to the inner wall of the enclosure 12. The cover 78 is made of the same insulating material as the cover 66. The cover 78 includes a cover portion 78a and a passage portion 78b.

[061] Cover portion 78a retains busbars 72, 74, 76 covering body portions 72a, 74a, 76a. Cover portion 78a isolates body portions 72a, 74a, 76a from the outside of busbars 72, 74, 76. In accordance with body portions 72a, 74a, 76a located in front of inverter 20, cover portion 78a extends linearly in a left-to-right direction. Cover portion 78a has a quadrilateral prism shape. Passage portion 78b is located at one end of cover portion 78a that is closest to motor 14.

[062] Passage portion 78b is integrally formed with cover portion 78a. Passage portion 78b has a flattened shape extending from the end of cover portion 78a to a position between inverter 20 and motor 14. Passage portion 78b has a space within it, which is shown by a dashed line. The internal space of passage portion 78b is a passage 78c through which a coolant flows. Passage 78c extends from the end of cover portion 78a to a position between inverter 20 and motor 14. Busbars 72, 74, 76 penetrate the internal space of passage portion 78b. Passage portion 78b includes a partition wall 78d that surrounds busbars 72, 74, 76 that penetrate the internal space. Busbars 72, 74, 76 are Petition 870250084702, dated 09 / 19 / 2025, p. 25 / 49 17 / 25 isolated from passage 78c by the separation wall 78d.

[063] Passage 78c communicates with an input 78e defined in passage portion 78b, at its upper end. Input 78e is defined in a cylindrical portion 78f situated at an upper end of passage portion 78b. The cylindrical portion 78f extends from passage portion 78b towards inverter 20 along the left-right direction and bends upwards at its intermediate position. The body portion 78f projects upwards from the upper surface 12a of the housing 12. Specifically, the cylindrical portion 78f is situated above a front end of the housing 12 and in front of its uppermost end. Passage 78c communicates with an output 78g defined in passage portion 78b below input 78e. Output 78g is defined in a cylindrical portion 78h located in passage portion 78b. The cylindrical portion 78h extends from passage portion 78b towards inverter 20 along the left-to-right direction.The cylindrical portion 78h is connected to the cylindrical portion 66h via a communication tube (not shown). In this way, passage 78c communicates with passage 66d through outlet 78g and inlet 66g. (Refrigerant flow)

[064] As shown in Figure 2, a cooling unit 80 is located above the drive unit 10. As shown in Figure 9, at least one cooling circuit 110 to cool the motor 14 and the inverter 20 is mounted on the electric vehicle 2. A coolant flow is shown with bold arrows in the cooling circuit 110. Figure 9 shows a power supply order 120 indicating a power supply order between the battery 6 and the motor 14 via the inverter 20. The cooling unit 80 cools the power module 22 by the coolant flowing through at least one cooling circuit 110. The cooling unit 80 is located above the power module 22. The coolant is a liquid coolant (i.e., LLC) for cooling one or more devices. Petition 870250084702, dated 09 / 19 / 2025, page 26 / 49 18 / 25 mounted on the electric vehicle 2. Each cooling circuit 110 includes a tube 116 where the coolant flows, a radiator 112 and a water pump 114. The cooling unit 80 cools the power module 22 by the coolant flowing through the tube around the power module 22.

[065] Busbars 66d, 78c of busbars 60, 70 are included in a cooling circuit for inverter 20. Specifically, inlet 78e is connected to a tube extending from cooling unit 80. Thus, the coolant in cooling unit 80 flows into busbar 78c through inlet 78e. In busbar 78c, the coolant flows down from inlet 78e and reaches outlet 78g. The coolant flowing through busbar 78c cools busbars 72, 74, 76 by exchanging heat with body portions 72a, 74a, 76a of busbars 72, 74, 76.

[066] The refrigerant flows out of outlet 78g and then flows into passage 66d through inlet 66g. In passage 66d, the refrigerant flows down from inlet 66g and reaches outlet 66j. The refrigerant flowing through passage 66d exchanges heat with busbars 62, 64 as it flows along body portions 62a, 64a of busbars 62, 64. In this way, busbars 62, 64 are cooled. The refrigerant flows out of outlet 66j and then flows into a cooling unit tube 80 through the communication tube 12c. (Effects)

[067] Busbar unit 60 is configured to allow the refrigerant to flow along body portions 62a, 64a of busbars 62, 64. In this way, the heat from busbars 62, 64 can be efficiently released to the refrigerant. The same applies to busbar unit 70, and in this way, the heat from busbars 72, 74, 76 can be efficiently released to the refrigerant.

[068] In the busbar unit 60, the passage 66d for the refrigerant is integrally formed with the cover 66 which retains the busbars 62, 64. This Petition 870250084702, dated 09 / 19 / 2025, page 27 / 49 19 / 25 form, there is no need to provide a separate passage for the refrigerant. The same applies to the 70 bus unit.

[069] In bus unit 60, inlet 66g is located at the upper end of passage 66d and outlet 66j is located at the lower end of passage 66d. This configuration allows the refrigerant in passage 66d to flow smoothly from the upper side to the lower side. The same applies to bus unit 70.

[070] The inlet 78e of the busbar unit 70 is situated to project upwards from the upper surface 12a of the housing 12. This enables the inlet 78e to communicate easily with the cooling unit tube 80 situated above the drive unit 10. The cylindrical portion 78f in which the inlet 78e is defined is situated above the front end of the housing 12 and in front of its uppermost end. This makes available a space above the drive unit 10.

[071] The cover 66 of the busbar unit 60 is located in a space between the inverter 20 and the motor 14. The cover 66 is curved along the direction of rotation of the shaft gear 32. The busbars 62, 64 are also curved following the shape of the cover 66. The shape of the cover 66 follows the shape of the motor 14. Thus, the busbar unit 60 can be arranged around the shaft gear 32. Furthermore, as shown in Figure 6, the busbar unit 60 substantially completely overlaps the motor 14 as viewed in the direction along the central geometric axis X. This allows for a reduction in the size of the drive unit 10. Thus, the space in the electric vehicle 2 can be efficiently used.

[072] The lower surface 12b of the housing 12 of the drive unit 10 is inclined upwards from the front towards the rear. This configuration creates a space below the lower surface 12b. In this way, a Petition 870250084702, dated 09 / 19 / 2025, page 28 / 49 20 / 25 space for electric vehicle components 2. In the drive unit 10, the connector 28 that connects the battery 6 to the inverter 20 can be located below the lower surface 12b. The battery 6 is located below the floor panel of the electric vehicle 2. The above configuration allows the connector 28 to be located close to the battery 6. As a result, the power cable 7 can be shortened and, in this way, space intended for the power cable 7 can be reduced. The battery 6 can be at least partially located below the drive unit 10.

[073] In drive unit 10, noise filter 26, filtering capacitor 24 and power module 22 of inverter 20 are arranged in that order from bottom to top, and thus noise filter 26 is positioned close to connector 28. This allows the wiring for power supply from connector 28, through noise filter 26 and filtering capacitor 24 to power module 22, in that order, to be shortened.

[074] In drive unit 10, power module 22, filtering capacitor 24, and noise filter 26 overlap motor 14 as visualized in the direction along the central geometric axis X of motor shaft 14b. This configuration allows the inverter 20 to be disposed in a space around motor shaft 14b created by a dimensional difference between motor 14 and shaft gear 32, i.e., the dimensional difference between them. In this way, the space created by the dimensional difference between motor 14 and shaft gear 32 can be efficiently used. In this configuration, the integration rate of inverter 20 can be improved compared to, for example, a configuration in which the inverter 20 is collectively disposed in a space above motor 14, and thus the space can be effectively used.

[075] As shown in Figure 3, in a radial direction of the shaft gear 32, the inverter 20, that is, the power module 22, the filtering capacitor 24 and the noise filter 26, is arranged to overlap the shaft gear 32. As Petition 870250084702, dated 09 / 19 / 2025, page 29 / 49 21 / 25 viewed in the left-to-right direction, shaft gear 32 is surrounded by power module 22, filtering capacitor 24, and noise filter 26. Shaft gear 32 overlaps at least one of power module 22, filtering capacitor 24, and noise filter 26 in a radial direction of shaft gear 32 along its entire length along the central geometric axis X. Thus, power module 22, filtering capacitor 24, and noise filter 26 may be arranged in the space around shaft gear 32 created by the dimensional difference between motor 14 and shaft gear 32. In a variant, the inverter 20, specifically any one of power module 22, filtering capacitor 24, and noise filter 26, may be arranged to overlap at least partially shaft gear 32 in a radial direction of shaft gear 32.For example, at least one part of the shaft gear 32 along the central geometric axis X may not overlap with any of the power module 22, the filtering capacitor 24, and the noise filter 26 in a radial direction of the shaft gear 32.

[076] The inverter 20 power module 22, filtering capacitor 24 and noise filter 26 are arranged in different positions and therefore the curved space around the shaft gear 32 can be used efficiently.

[077] The maximum length of power module 22 along the direction of rotation R of shaft gear 32 is greater than its maximum length along a radial direction of shaft gear 32. Similarly, the maximum length of filtering capacitor 24 along the direction of rotation of shaft gear 32 is greater than its maximum length along a radial direction of shaft gear 32. Similarly, the maximum length of noise filter 26 along the direction of rotation of shaft gear 32 is greater than its maximum length along a radial direction of shaft gear 32. In other words, power module 22, filtering capacitor 24, and noise filter Petition 870250084702, dated 09 / 19 / 2025, pp. 30 / 49 22 / 25 are arranged so that their longitudinal directions are along the direction of rotation of shaft gear 32 and their short directions are along radial directions of shaft gear 32. This allows for efficient use of the space around shaft gear 32 and suppresses the expansion of inverter 20 in the radial directions of shaft gear 32.

[078] In the direction of rotation of shaft gear 32, the angle AN around the central geometric axis X between the end 22b of the power module 22 that faces the opposite direction to the filter capacitor 24 and the end 26b of the noise filter 26 that faces the opposite direction to the filter capacitor 24 is greater than or equal to 240 degrees. The angle AN may be greater than or equal to 180 degrees. This configuration allows for efficient use of the space around shaft gear 32.

[079] As most of the countershaft gear 34 and countershaft gear 42 is situated below the plane P that connects the central geometric axis X of the motor shaft 14b and the central geometric axis Y of the crown 50, a large space can be ensured for the inverter 20 above the plane P. An angular range of the space above the plane P around the central geometric axis X is greater than an angular range of the space below the plane P around the central geometric axis X.

[080] Power module 22 and countershaft gear 34 are arranged opposite each other with shaft gear 32 interposed between them. The diameter of countershaft gear 34 is larger than that of shaft gear 32 to provide the function of reducing the speed of motor 14. Furthermore, power module 22 has the largest size among the components of inverter 20. Since power module 22 and countershaft gear 34, being large in size, are arranged opposite each other with shaft gear 32 interposed between them, power module 22 and countershaft gear 34 can be arranged without interference. Shaft gear 32 has the smallest diameter among the plurality of gears of the gear unit 30. Thus, the arrangement Petition 870250084702, dated 09 / 19 / 2025, page 31 / 49 23 / 25 of power module 22, the filtering capacitor 24 and the noise filter 26 around shaft gear 32 make it possible for the external size of the drive unit 10 to be reduced compared to a configuration in which they are arranged around a gear other than shaft gear 32 among the plurality of gears of the gear unit 30.

[081] The shaft gear 32 is an example of a “first gear”. The countershaft gear 34 is an example of a “second gear”.

[082] Although specific examples of the present disclosure have been described in detail above, these examples are merely illustrative and do not impose any limitation on the scope of the patent claims. The technology described in the patent claims also encompasses various alterations and modifications to the specific examples described above. Variants of the above embodiment are described below.

[083] (Variant 1) The drive unit 10 may be located at the rear end of the vehicle. In this case, the lower surface 12b of the drive unit 10 may be inclined upwards towards the center of the electric vehicle 2 in the front-to-rear direction, i.e., towards the front of the electric vehicle 2. The connector 28 may be located below the front end of the drive unit 10 and in front of its lower end. Furthermore, the inlet 78e may be located above the rear end of the drive unit 10 and behind its upper end.

[084] (Variant 2) In this embodiment, the power module 22, the filtering capacitor 24, and the noise filter 26 are arranged adjacent to each other along the direction of rotation R. However, at least two of the power module 22, the filtering capacitor 24, and the noise filter 26 may be arranged adjacent to each other in a radial direction of the shaft gear 32. Alternatively, at least two of the power module 22, the filtering capacitor 24, and the noise filter 26 may Petition 870250084702, dated 09 / 19 / 2025, pp. 32 / 49 24 / 25 can be arranged adjacent to each other along the central geometric axis X, that is, in the left-to-right direction. For example, the power module 22, the filtering capacitor 24, and the noise filter 26 can be arranged collectively above the shaft gear 32.

[085] (Variant 3) The number of gears in gear unit 30 is not limited. In this embodiment, the rotational speed of motor 14 is reduced in two stages; however, the rotational speed of motor 14 can be reduced in three stages. In this case, gear unit 30 can include at least eight gears. The shaft gear 32 can have the smallest diameter among the plurality of gears in gear unit 30.

[086] (Variant 4) In one of the busbar units 60, 70, the refrigerant passage may not be defined on cover 66, 78. In this case, the refrigerant passage may be located in a position other than cover 66, 78.

[087] (Variant 5) The 60 bus unit may not be curved along the direction of rotation R. For example, the 60 bus unit may be linearly formed.

[088] (Variant 6) At least one of the busbar units 60, 70 may be used in an electrical device other than electric vehicle 2. In particular, it may be used by a busbar used in an environment associated with at least one of high current and high temperature.

[089] The technical elements explained in this description or in the drawings provide technical utility independently or through various combinations. This disclosure is not limited to the combinations described at the filing date of the claims. Furthermore, the purpose of the examples illustrated by this description or drawings is to satisfy multiple objectives simultaneously, and satisfying any one of these objectives confers utility to this disclosure. List of reference signs Petition 870250084702, dated 09 / 19 / 2025, pp. 33 / 49 25 / 25 2: Electric vehicle, 4: Body, 6: Battery, 10: Drive unit, 12: Casing, 12b: Bottom surface, 12c: Communication tube, 14: Motor, 14b: Motor shaft, 20: Inverter, 22: Power module, 24: Filtering capacitor, 26: Noise filter, 28: Connector, 30: Gear unit, 32: Shaft gear, 34: Countershaft gear, 42: Countershaft gear, 44: Shaft, 50: Crown, 52: Differential gears, 60: Bus unit, 62, 64: Buses, 66: Cover, 70: Bus unit, 72, 74, 76: Buses, 80: Cooling unit, 90: Drive shaft, X: Central geometric axis Petition 870250084702, dated 09 / 19 / 2025, pp. 34 / 49

Claims

1 / 2 CLAIMS 1. Drive device (10) CHARACTERIZED in that it comprises: a motor (14) comprising a motor shaft (14b); a first gear (32) configured to rotate around a central geometric axis (X) of the motor shaft (14b); and an inverter (20) comprising a plurality of components (22, 24, 26) configured to be used to control the motor (14), wherein at least one part of the inverter (20) overlaps the motor (14) in a view along an axial direction of the central geometric axis (X), and at least one part of the inverter (20) overlaps the first gear (32) in a view along a radial direction of the first gear (32).

2. Drive device (10), according to claim 1, CHARACTERIZED in that the inverter (20) is disposed below a cooling unit (80) configured to cool the inverter (20).

3. Actuating device (10), according to claim 1 or 2, CHARACTERIZED in that the plurality of components (22, 24, 26) comprises: a power module (22) comprising a plurality of switching elements; a filtering capacitor (24); and a noise filter (26), and the power module (22), the filtering capacitor (24) and the noise filter (26) are arranged in that order from an upper side towards a lower side.

4. Drive device (10), according to claim 3, CHARACTERIZED in that a length of each of the power module (22), the filtering capacitor (24) and the noise filter (26) along a direction of rotation (R) of the first gear (32) is longer than a length of each of the power module (22), the filtering capacitor (24) and the noise filter (26) along the radial direction of the first gear (32), and a strip, in the direction of rotation (R) of the first gear (32), from an end opposite the filtering capacitor (24) of the power module (22) to an end opposite the filtering capacitor (24) of the noise filter (26) is 180° or more around the central geometric axis (X).

5. Drive device (10), according to claim 3 or 4, CHARACTERIZED in that it further comprises a second gear (34) configured to mesh with the first gear (32), wherein the first gear (32) is disposed between the second gear (34) and the power module (22).

6. Drive device (10), according to claim 5, CHARACTERIZED in that the second gear (34) is arranged below the first gear (32) and the power module (22).

7. Drive device (10), according to any one of claims 1 to 6, CHARACTERIZED in that it comprises: a plurality of shafts including the motor shaft (14b) and a drive shaft (90); and one or more gears arranged on each of the plurality of shafts, wherein the one or more gears arranged on the motor shaft (14b) include the first gear (32).

8. Actuating device (10), according to claim 7, CHARACTERIZED in that an outside diameter of the first gear (32) is the smaller of one or more outside diameters of one or more gears. Petition 870250084702, dated 19 / 09 / 2025, pp. 48 / 49

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