Drive device

Abstract

One embodiment of a drive device according to the present invention comprises: a motor having a rotor that rotates about a central axis; a first inverter and a second inverter that are disposed along an outer peripheral surface of the motor and are respectively connected to the motor; and a flow path through which a fluid flows. The first inverter has a first power module, a first capacitor, and a first heat sink. The second inverter has a second power module, a second capacitor, and a second heat sink. The flow path causes a fluid to flow through the first heat sink and the second heat sink. A direction parallel to the central axis is defined as a first direction, a direction orthogonal to the first direction is defined as a second direction, and a direction orthogonal to both the first direction and the second direction is defined as a third direction. The first inverter is disposed on one side in the second direction and on one side in the third direction with respect to the central axis. The second inverter is disposed on the one side in the second direction and on the other side in the third direction with respect to the central axis.

Description

Drive device

[0001] The present invention relates to a drive device.

[0002] In recent years, as a drive device mounted on an electric vehicle or the like, development of a drive device including a motor and an inverter connected to the motor has been carried out. Further, in such a drive device, a structure in which a plurality of inverters are connected to one motor has been proposed for the purpose of efficient driving and ensuring redundancy (for example, Japanese Patent Application Laid-Open No. 2022-165651).

[0003] Japanese Patent Application Laid-Open: Japanese Patent Application Laid-Open No. 2022-165651

[0004] A drive device including a plurality of inverters tends to be large in size, and therefore it is required to efficiently arrange each inverter with respect to the motor.

[0005] In view of the above circumstances, one object of the present invention is to provide a drive device having a plurality of inverters that can be miniaturized.

[0006] One aspect of the drive device of the present invention includes a motor having a rotor that rotates about a central axis, a first inverter and a second inverter that are arranged along the outer peripheral surface of the motor and are each connected to the motor, and a flow path through which a fluid flows. The first inverter has a first power module, a first capacitor, and a first heat sink. The second inverter has a second power module, a second capacitor, and a second heat sink. The flow path allows a fluid to flow through the first heat sink and the second heat sink. A direction parallel to the central axis is defined as a first direction, a direction orthogonal to the first direction is defined as a second direction, and a direction orthogonal to both the first direction and the second direction is defined as a third direction. The first inverter is arranged on one side in the second direction and on one side in the third direction with respect to the central axis. The second inverter is arranged on one side in the second direction and on the other side in the third direction with respect to the central axis.

[0007] According to one aspect of the present invention, a drive device having a plurality of inverters that can be miniaturized can be provided.

[0008] Figure 1 is a schematic diagram showing the configuration of each part of a drive unit according to one embodiment. Figure 2 is a perspective view of the drive unit according to one embodiment. Figure 3 is a cross-sectional view of the drive unit according to one embodiment. Figure 4 is a plan view of the drive unit according to one embodiment. Figure 5 is a cross-sectional view of the heat sink according to one embodiment. Figure 6 is a cross-sectional view of a modified drive unit.

[0009] The following description of the drive system of the embodiment will be based on the drawings. In the following description, the direction of gravity will be defined and explained based on the positional relationship when the drive system is mounted on a vehicle located on a horizontal road surface.

[0010] In the following explanation, unless otherwise specified, the radial direction centered on the central axis J1 of the motor 2 will be simply referred to as the "radial direction," and the circumferential direction centered on the central axis J1, that is, the direction around the axis of the central axis J1, will be simply referred to as the "circumferential direction."

[0011] Each figure illustrates a first direction D1, a second direction D2, and a third direction D3, each orthogonal to the other. The first direction D1 is parallel to the central axis J1. In this embodiment, the first direction D1 is the left-right direction of the vehicle on which the drive unit 100 is mounted. The second direction D2 is orthogonal to the first direction. In this embodiment, the second direction D2 coincides with the vertical direction. The third direction D3 is orthogonal to both the first direction D1 and the second direction D2. In this embodiment, the third direction D3 is the front-rear direction of the vehicle on which the drive unit 100 is mounted.

[0012] In the following explanation, one side of the first direction D1 (hereinafter referred to as "one side of the first direction") is the direction opposite to the direction indicated by the arrow representing the first direction D1 in the figure (-D1), and the other side of the first direction D1 (hereinafter referred to as "the other side of the first direction") is the direction indicated by the arrow representing the first direction D1 in the figure (+D1). Similarly, one side of the second direction D2 (hereinafter referred to as "one side of the second direction") is the direction indicated by the arrow representing the second direction D2 in the figure (+D2), and the other side of the second direction D2 (hereinafter referred to as "the other side of the second direction") is the direction opposite to the direction indicated by the arrow representing the second direction D2 in the figure (-D2). Furthermore, one side of the third direction D3 (hereinafter referred to as "one side of the third direction") is the direction in which the arrow indicating the third direction D3 in the figure points (+D3), and the other side of the third direction D3 (hereinafter referred to as "the other side of the third direction") is the direction opposite to the direction in which the arrow indicating the third direction D3 in the figure points (-D3).

[0013] <Drive System> Figure 1 is a schematic diagram showing the configuration of each part of the drive system 100 of this embodiment. Figure 2 is a perspective view of the drive system 100 of this embodiment. The drive system 100 of this embodiment is installed in vehicles that use a motor 2 as a power source, such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and electric vehicles (EVs), and is used as the power source.

[0014] As shown in Figure 1, the drive unit 100 comprises a motor 2, a power transmission mechanism 3, a housing 6, and a control unit 7. The housing 6 houses the motor 2, the power transmission mechanism 3, and the control unit 7.

[0015] <Housing> As shown in Figure 1, the housing 6 has a first housing section 6A, a second housing section 6B, and a third housing section 6C. The first housing section 6A houses the motor 2. The second housing section 6B houses the power transmission mechanism 3. The third housing section 6C houses the control unit 7. Oil O is stored in the internal space of the second housing section 6B.

[0016] As shown in Figure 2, the third housing section 6C is composed of a box-shaped section 6f that opens upward (+D2) and a cover 64 that covers the opening of the box-shaped section 6f. The control unit 7 is placed in the space enclosed by the box-shaped section 6f and the cover 64.

[0017] As shown in Figure 1, an external pipe 98 is connected to the third housing section 6C. The external pipe 98 is configured in a loop shape. The external pipe 98 supplies fluid L to a flow path 90 provided inside the third housing section 6C. A radiator (not shown) for cooling the fluid L and a pump for pressurizing the fluid L are arranged along the path of the external pipe 98. The external pipe 98 delivers low-temperature fluid L to the flow path 90. The external pipe 98 also recovers the fluid L that has absorbed heat in the flow path 90 and whose temperature has risen. The pump may be provided on the outer surface of the housing 6 or inside the housing 6.

[0018] <Motor> The motor 2 in this embodiment is, for example, an inner rotor type three-phase AC motor. The motor 2 has both the function of outputting power as a motor and the function of generating electricity as a generator. The motor 2 may be used as either a motor or a generator. Furthermore, the configuration of the motor 2 is not limited to this embodiment, and may be, for example, a four-phase or more AC motor.

[0019] As shown in Figure 1, the motor 2 comprises a rotor 20 that rotates about a central axis J1, and a stator 25 located radially outward from the rotor 20.

[0020] The stator 25 is held in the housing 6. The stator 25 surrounds the rotor 20 from the radially outer side. The stator 25 has an annular stator core 27 centered on the central axis J1, a coil 26 mounted on the stator core 27, and an insulator (not shown) interposed between the stator core 27 and the coil 26.

[0021] The coil 26 has a first coil end 2a that protrudes to one side (-D1) in the first direction of the stator core 27, and a second coil end 2b that protrudes to the other side (+D1) in the first direction of the stator core 27. The first coil end 2a and the second coil end 2b are formed by bundling coil wires together.

[0022] The rotor 20 includes a shaft 21, a rotor core 24 fixed to the outer circumferential surface of the shaft 21, and a plurality of magnets (not shown) fixed to the rotor core 24. The shaft 21 extends along the central axis J1. The shaft 21 is supported by the housing 6 so as to be rotatable about the central axis J1. The rotor core 24 is fixed to the outer circumferential surface of the shaft 21. The rotor core 24 is columnar in shape and extends along the central axis J1.

[0023] <Power Transmission Mechanism> The power transmission mechanism 3 is located on the other side (+D1) of the motor 2 in the first direction. The power transmission mechanism 3 is connected to the rotor 20 and transmits the rotation of the rotor 20, outputting power from the output shaft 55. The power transmission mechanism 3 has a first shaft 44, a second shaft 45, a first gear 41, a second gear 42, a third gear 43, and a differential gear 5. The differential gear 5 has a ring gear 51 and a pair of output shafts 55. Wheels (not shown) are attached to the ends of each of the pair of output shafts 55.

[0024] The first shaft 44 extends in a first direction D1 with respect to the central axis J1. The first shaft 44 is connected at one end in the first direction (-D1) to the other end in the first direction (+D1) of the shaft 21. As a result, the first shaft 44 is connected to the rotor 20 of the motor 2 and rotates together with the rotor 20. The first gear 41 is provided on the outer circumferential surface of the first shaft 44 and rotates about the central axis J1. The second shaft 45 is rotatable about an intermediate axis J2 parallel to the central axis J1. The second gear 42 and the third gear 43 are provided on the outer circumferential surface of the second shaft 45. The second gear 42 and the third gear 43 rotate about the intermediate axis J2. The second gear 42 meshes with the first gear 41. The third gear 43 meshes with the ring gear 51 of the differential 5. The differential gear 5 is rotatable about a differential axis J3 that is parallel to the central axis J1. The differential gear 5 transmits torque from the third gear 43 to the output shaft 55 while absorbing the speed difference between the left and right wheels when the vehicle turns. The pair of output shafts 55 are each rotatable about the differential axis J3.

[0025] As shown in Figure 2, the central axis J1, intermediate axis J2, and differential axis J3 are aligned along the third direction D3. The intermediate axis J2 is located on the other side of the third direction (-D3) relative to the central axis J1. Furthermore, the differential axis J3 is located on the other side of the third direction (-D3) relative to the intermediate axis J2. Therefore, when viewed from the first direction D1, the power transmission mechanism 3 protrudes from the motor 2 on the other side of the third direction (-D3). Also, when viewed from the first direction D1, the second housing 6B protrudes from the first housing 6A on the other side of the third direction (-D3).

[0026] <Control Unit> Figure 3 is a cross-sectional view of the drive unit 100 of this embodiment. Figure 4 is a plan view of the drive unit 100 of this embodiment. Note that in Figure 4, the cover 64 that covers the control unit 7 and the busbar holder 9, which will be described later, are not shown.

[0027] As shown in Figure 3, the control unit 7 includes a first inverter 70, a second inverter 80, a flow path member 95, a busbar unit 8, and a control board 7a. That is, the drive device 100 includes a first inverter 70, a second inverter 80, a flow path member 95, a control board 7a, and a busbar unit 8.

[0028] Furthermore, as shown in Figure 1, the control unit 7 is provided with a flow path 90. That is, the drive unit 100 has a flow path 90. Fluid L flows through the flow path 90. The flow path 90 has a first cooling flow path section 93, a second cooling flow path section 94, and a connecting flow path section 91. The first cooling flow path section 93 is provided inside the first inverter 70. The second cooling flow path section 94 is provided inside the second inverter 80. The connecting flow path section 91 is provided inside the flow path member 95.

[0029] As shown in Figure 3, the first inverter 70 and the second inverter 80 each convert the DC current supplied from the battery (not shown) into AC current and supply it to the motor 2. Therefore, the first inverter 70 and the second inverter 80 are connected to the battery (not shown) and the motor 2, respectively.

[0030] The first inverter 70 and the second inverter 80 are located above the motor 2 (+D2). In this embodiment, at least a portion of the first inverter 70 overlaps with the motor 2 when viewed from the second direction D2. Similarly, at least a portion of the second inverter 80 overlaps with the motor 2 when viewed from the second direction D2.

[0031] The first inverter 70 and the second inverter 80 are arranged along the outer circumferential surface 2c of the motor 2. The first inverter 70 and the second inverter 80 are arranged side by side in the third direction D3. The first inverter 70 is located on one side (+D3) of the third direction relative to the second inverter 80. Here, the outer circumferential surface 2c of the motor 2 is the surface facing radially outward of the motor 2. Therefore, the first inverter 70 and the second inverter 80 are arranged side by side along the circumferential direction centered on the central axis J1. The lower end of the first inverter 70 (the end on the other side (-D2) of the second direction) is located above (+D2) the upper end of the motor 2 (the end on one side (+D2) of the second direction). On the other hand, the lower end of the second inverter 80 (the end on the other side (-D2) of the second direction) is located below (-D2) the upper end of the motor 2 (the end on one side (+D2) of the second direction).

[0032] The dimensions of the first inverter 70 and the second inverter 80 in the second direction D2 are the same. The upper end of the first inverter 70 is located above (+D2) the upper end of the second inverter 80. The lower end of the first inverter 70 is located below (-D2) the upper end of the second inverter 80. The lower end of the first inverter 70 is located above (+D2) the lower end of the second inverter 80. In other words, the first inverter 70 is located slightly above (+D2) the second inverter 80.

[0033] The first inverter 70 is located on one side (+D3) of the third direction with respect to the central axis J1. On the other hand, the second inverter 80 is located on the other side (-D3) of the third direction with respect to the central axis J1. Therefore, the first inverter 70 is positioned on one side (+D2) of the second direction and one side (+D3) of the third direction with respect to the central axis J1, and the second inverter 80 is positioned on one side (+D2) of the second direction and the other side (-D3) of the third direction with respect to the central axis J1.

[0034] The outer shape of the motor 2 is circular when viewed from the first direction D1. Therefore, the outer surface 2c of the motor 2 is approximately circular with the central axis J1 as the center when viewed from the first direction D1. Of the regions along the outer surface 2c of the motor 2, the region on one side of the second direction (+D2) and one side of the third direction (+D3) of the central axis J1, and the region on one side of the second direction (+D2) and the other side of the third direction (-D3) tend to become dead space. According to this embodiment, by arranging the first inverter 70 and the second inverter 80 in these regions, it is possible to suppress the overall enlargement of the drive unit 100 in the second direction D2 and the third direction D3. In other words, according to this embodiment, the dead space around the motor 2 can be effectively utilized to miniaturize the drive unit 100.

[0035] Furthermore, the second inverter 80 is located directly above the differential axis J3. In this specification, "directly above" means that at least a portion of it overlaps when viewed from above and in the vertical direction.

[0036] In this embodiment, the second inverter 80 is located to the other side in the third direction (-D3) relative to the first inverter 70. Also, as described above, the power transmission mechanism 3 protrudes to the other side in the third direction (-D3) relative to the motor 2 when viewed from the first direction D1. Therefore, when viewed from the first direction D1, most of the second inverter 80 is positioned overlapping the power transmission mechanism 3. In this embodiment, even if the second inverter 80 is positioned lower (-D2), it overlaps with the power transmission mechanism 3, so the projected area of ​​the drive unit 100 in the first direction D1 does not increase significantly. This makes it possible to create space above the second inverter 80 for other components (in this embodiment, the control board 7a). In other words, according to this embodiment, the drive unit 100 can be miniaturized by positioning the second inverter 80 below the first inverter 70.

[0037] Furthermore, in this embodiment, the drive unit 100 can be miniaturized in the third direction D3 by shifting the first inverter 70 to the other side in the third direction (-D3). However, since the first inverter 70 is arranged along the outer circumferential surface 2c of the motor 2, it is necessary to shift the first inverter 70 to one side in the third direction (+D3) and also to the upper side to avoid interference with the motor 2. For this reason, the first inverter 70 is positioned slightly above the second inverter 80.

[0038] As shown in Figure 4, the dimensions of the first inverter 70 and the second inverter 80 are the same in the first direction D1. The dimensions of the first direction D1 of the first inverter 70 and the second inverter 80 are both smaller than the dimensions of the first direction D1 of the motor 2.

[0039] The end 70a of the first inverter 70 on one side in the first direction (-D1) is located further to the other side in the first direction (+D1) than the end 80a of the second inverter 80 on one side in the first direction (-D1). The end 70a of the first inverter 70 on one side in the first direction (-D1) is located further to the other side in the first direction (-D1) than the end 80b of the second inverter 80 on the other side in the first direction (+D1). The end 70b of the first inverter 70 on the other side in the first direction (+D1) is located further to the other side in the first direction (+D1) than the end 80b of the second inverter 80 on the other side in the first direction (+D1). In other words, the first inverter 70 is located slightly further to the other side in the first direction (+D1) than the second inverter 80.

[0040] As shown in Figure 3, the first inverter 70 includes a first power module 71, a first capacitor 72, a first heat sink 73, and a first drive board 74. Similarly, the second inverter 80 includes a second power module 81, a second capacitor 82, a second heat sink 83, and a second drive board 84. In other words, the first inverter 70 and the second inverter 80 have similar configurations.

[0041] In the first inverter 70 of this embodiment, the first drive board 74, the first power module 71, the first heat sink 73, and the first capacitor 72 are arranged in this order from the top (+D2) to the bottom (-D2). The first power module 71 and the first capacitor 72 are fixed to the first heat sink 73 from both sides in the second direction D2. That is, the first power module 71, the first capacitor 72, and the first heat sink 73 are integrated. According to this embodiment, the assembly process can be completed by arranging the integrated unit of the first power module 71, the first capacitor 72, and the first heat sink 73 inside the third housing section 6C. In addition, according to this embodiment, by integrating the first power module 71, the first capacitor 72, and the first heat sink 73, it becomes easier to arrange these components without gaps inside the third housing section 6C, thereby enabling miniaturization of the drive device 100.

[0042] Similarly, in the second inverter 80 of this embodiment, the second drive board 84, the second power module 81, the second heat sink 83, and the second capacitor 82 are arranged in this order from the top (+D2) to the bottom (-D2). The second power module 81 and the second capacitor 82 are fixed to the second heat sink 83 from both sides in the second direction D2. In other words, the second power module 81, the second capacitor 82, and the second heat sink 83 of this embodiment are integrated. According to this embodiment, the assembly process can be completed by arranging the integrated unit of the second power module 81, the second capacitor 82, and the second heat sink 83 inside the third housing section 6C. In addition, according to this embodiment, by integrating the second power module 81, the second capacitor 82, and the second heat sink 83, it becomes easier to arrange these components inside the third housing section 6C without gaps, thereby enabling miniaturization of the drive device 100.

[0043] The first power module 71 and the second power module 81 have the same configuration. The first capacitor 72 and the second capacitor 82 have the same configuration. The first heat sink 73 and the second heat sink 83 have the same configuration. The first drive board 74 and the second drive board 84 have the same configuration. In the following description, when the first power module 71 and the second power module 81 are not distinguished, they are simply referred to as power modules 71, 81. Similarly, when the first capacitor 72 and the second capacitor 82 are not distinguished, they are simply referred to as capacitors 72, 82. When the first heat sink 73 and the second heat sink 83 are not distinguished, they are simply referred to as heat sinks 73, 83. When the first drive board 74 and the second drive board 84 are not distinguished, they are simply referred to as drive boards 74, 84.

[0044] The power modules 71, 81 include a plurality of switching devices 71a, 81a and circuit boards 71b, 81b on which the switching devices 71a, 81a are mounted. The circuit boards 71b, 81b extend along a plane orthogonal to the second direction D2. The circuit boards 71b, 81b are rectangular with the first direction D1 as the longitudinal direction when viewed from the second direction D2. The switching devices 71a, 81a are mounted on the surfaces of the circuit boards 71b, 81b facing the upper side (+D2).

[0045] In the power modules 71, 81 of the present embodiment, three switching devices 71a, 81a corresponding to the U phase, V phase, and W phase are provided respectively. Each of the switching devices 71a, 81a has two switching elements 71e, 81e corresponding to the upper arm and the lower arm. Here, the switching element of the first power module 71 is referred to as the first switching element 71e, and the switching element of the second power module 81 is referred to as the second switching element 81e. In the present embodiment, the first power module 71 has a plurality (six in this embodiment) of first switching elements 71e. Similarly, the second power module 81 has a plurality (six in this embodiment) of second switching elements 81e.

[0046] The switching elements 71e and 81e are, for example, insulated gate bipolar transistors (IGBTs: Insulated Gate Bipolar Transistors). Also, the switching elements 71e and 81e may be field-effect transistors such as metal-oxide-semiconductor field-effect transistors (MOSFETs: Metal-Oxide-Semiconductor Field-Effect Transistors).

[0047] In the present embodiment, the three switching devices 71a of the first power module 71 are arranged in the first direction D1. Also, the two first switching elements 71e included in one switching device 71a are arranged in the third direction D3. Therefore, the six first switching elements 71e are mounted on the circuit board 71b in a 3×2 array with three in the first direction D1 and two in the third direction D3. Similarly, the three switching devices 81a of the second power module 81 are arranged in the first direction D1. Also, the two second switching elements 81e included in one switching device 81a are arranged in the third direction D3. Therefore, the six second switching elements 81e are mounted on the circuit board 81b in a 3×2 array with three in the first direction D1 and two in the third direction D3.

[0048] Here, when the first power module 71 is viewed from the second direction D2, the region where the plurality of first switching elements 71e are arranged is defined as the first element arrangement region A1. The first element arrangement region A1 is a mounting region provided on the upper surface of the circuit board 71b. The first element arrangement region A1 is the smallest rectangular region capable of arranging all the first switching elements 71e. In the present embodiment, the dimension of the first element arrangement region A1 in the first direction D1 is larger than the dimension of the first element arrangement region A1 in the third direction D3.

[0049] Similarly, when viewing the second power module 81 from the second direction D2, the region where multiple second switching elements 81e are arranged is defined as the second element arrangement region A2. The second element arrangement region A2 is a mounting region provided on the upper surface of the circuit board 81b. The second element arrangement region A2 is the smallest rectangular region in which all second switching elements 81e can be arranged. In this embodiment, the dimension of the second element arrangement region A2 in the first direction D1 is larger than the dimension of the second element arrangement region A2 in the third direction D3.

[0050] In this embodiment, the dimensions of the first element arrangement region A1 and the second element arrangement region A2 are larger in the first direction D1 than in the third direction D3. Therefore, the longitudinal direction of the first power module 71 and the second power module 81 can be set to the first direction D1, which is the axial direction of the motor 2. In other words, the first power module 71 and the second power module 81 can be miniaturized in the third direction D3. Generally, the motor 2 has first coil ends 2a and second coil ends 2b that protrude from both end faces in the first direction D1 of the stator core 27, so the dimension in the first direction D1 tends to be larger than the diameter. In this embodiment, the control unit 7 can be miniaturized in the third direction D3 without protruding from the motor 2 in the first direction D1.

[0051] Furthermore, in this embodiment, the plurality of first switching elements 71e of the first inverter 70 are arranged in a rectangular shape in the first direction D1 and the third direction D3. The number of first switching elements 71e arranged in the first direction D1 (3 in this embodiment) is greater than the number of first switching elements 71e arranged in the third direction D3 (2 in this embodiment). Similarly, the plurality of second switching elements 81e of the second inverter 80 are arranged in a rectangular shape in the first direction D1 and the third direction D3. The number of second switching elements 81e arranged in the first direction D1 (3 in this embodiment) is greater than the number of second switching elements 81e arranged in the third direction D3 (2 in this embodiment). According to this embodiment, it is possible to miniaturize the first power module 71 and the second power module 81 in the third direction D3.

[0052] Capacitors 72 and 82 are, for example, film capacitors. Capacitors 72 and 82 are connected between the battery (not shown) and the power modules 71 and 81. Capacitors 72 and 82 are provided to smooth the DC current supplied from the battery (not shown) to the power modules 71 and 81.

[0053] Figure 5 is a schematic diagram illustrating the structure of the first heatsink 73. While the first heatsink 73 is used as an example in this explanation, the second heatsink 83 has a similar structure.

[0054] The first heat sink 73 includes a base member 11 and a lid member 12. The base member 11 and the lid member 12 are assembled in a second direction D2 and fixed to each other.

[0055] The base member 11 is made of, for example, a resin material. The base member 11 may also be made of a metal material such as aluminum. The base member 11 is a flow path forming member. The base member 11 has a first opposing surface 11a facing upward (+D2) and a first cooling surface 11b facing downward. The first opposing surface 11a is provided with a recess 11c and a groove 11d that open upward (+D2). Fluid L is supplied to the recess 11c from the flow path 90. Therefore, fluid L flows inside the recess 11c. That is, the recess 11c constitutes a part of the flow path 90. More specifically, the recess 11c of the first heat sink 73 constitutes the first cooling flow path portion 93 (see Figure 1) of the flow path 90. Also, the recess 11c of the second heat sink 83 constitutes the second cooling flow path portion 94 (see Figure 1) of the flow path 90.

[0056] The groove 11d surrounds the recess 11c when viewed from the second direction D2. A sealing member 13, such as a packing, is placed inside the groove 11d.

[0057] The lid member 12 is made of a metal material such as a copper alloy or aluminum alloy with excellent thermal conductivity. The lid member 12 has a main body 12m and a plurality of fins 12f. The main body 12m is plate-shaped. The main body 12m has a second opposing surface 12a facing downward (-D2) and a second cooling surface 12b facing upward (+D2). The main body 12m is fixed to the base member 11 with the second opposing surface 12a in contact with the first opposing surface 11a. As a result, the main body 12m covers the openings of the recess 11c and the groove 11d. The main body 12m also compresses the sealing member 13 in the groove 11d. As a result, the sealing member 13 seals the base member 11 and the lid member 12 around the recess 11c, preventing the fluid L flowing in the recess 11c from flowing out of the first heat sink 73. Multiple fins 12f protrude downward (-D2) from the second opposing surface 12a of the main body portion 12m. The multiple fins 12f are arranged inside the recess 11c and come into contact with the fluid L flowing inside the recess 11c. By providing multiple fins 12f, a large contact area can be secured between the lid member 12 and the fluid L in the recess 11c, making it easier to transfer heat from the lid member 12 to the fluid L.

[0058] The first heatsink 73 contacts the first capacitor 72 at the first cooling surface 11b of the base member 11. The first heatsink 73 also contacts the first power module 71 at the second cooling surface 12b of the lid member 12. As a result, the first heatsink 73 transfers heat from the first power module 71 and the first capacitor 72 to the fluid L, cooling the first power module 71 and the first capacitor 72. Although not shown in the figures, the second heatsink 83 similarly contacts the second power module 81 and the second capacitor 82, cooling them as well.

[0059] In the flow path 90 of this embodiment, the first inverter 70 is positioned downstream of the second inverter 80. Therefore, the fluid L flowing through the flow path 90 cools the second inverter 80, and then cools the first inverter 70 while the fluid L has cooled the second inverter 80 and its temperature has risen. As a result, the cooling of the first inverter 70 tends to be insufficient compared to that of the second inverter 80. In other words, the temperature of the first inverter 70 tends to rise higher than that of the second inverter 80. For this reason, it is conceivable to make the surface area of ​​the first cooling flow path portion 93 inside the first heat sink 73 shown in Figure 1 larger than the surface area of ​​the second cooling flow path portion 94 inside the second heat sink 83. This makes it possible to match the amount of heat absorbed in the first heat sink 73 and the amount of heat absorbed in the second heat sink 83, thereby reducing the temperature difference between the first inverter 70 and the second inverter 80. As a means of making the surface area of ​​the first cooling flow path portion 93 larger than the surface area of ​​the second cooling flow path portion 94, for example, it is conceivable to increase the number of fins 12f of the first heat sink 73 compared to the number of fins 12f of the second heat sink 83.

[0060] As shown in Figure 3, according to this embodiment, the first heatsink 73 is positioned between the first power module 71 and the first capacitor 72, and cools them. According to this embodiment, the first power module 71 and the first capacitor 72 can be efficiently cooled by utilizing both sides of the first heatsink 73. Furthermore, according to this embodiment, the first heatsink 73, the first power module 71, and the first capacitor 72 can be easily integrated into one unit.

[0061] Similarly, the second heatsink 83 is positioned between the second power module 81 and the second capacitor 82, and cools them. According to this embodiment, the second power module 81 and the second capacitor 82 can be efficiently cooled by utilizing both sides of the second heatsink 83. Furthermore, according to this embodiment, the second heatsink 83, the second power module 81, and the second capacitor 82 can be easily integrated into a single unit.

[0062] As shown in Figure 3, in the first inverter 70 of this embodiment, the first capacitor 72 is located below (-D2) the first power module 71. The dimension of the first capacitor 72 in the third direction D3 is smaller than the dimension of the first heat sink 73 in the third direction D3. The first capacitor 72 is positioned to overlap the first power module 71, offset to one side in the third direction (+D3) when viewed from the second direction D2. The first inverter 70 of this embodiment is positioned above the motor 2 and along the outer circumferential surface 2c of the motor 2 on one side in the third direction (+D3). Since the outer circumferential surface 2c of the motor 2 is circular when viewed from the first direction D1, the region of the outer circumferential surface 2c of the motor 2 that faces the first inverter 70 slopes downward (-D2) as it moves toward one side in the third direction (+D3). According to this embodiment, by positioning the first power module 71 in the first inverter 70 towards one side in the third direction (+D3), the shape of the lower end of the first inverter 70 can be made to conform to the outer surface 2c of the motor 2. This allows the first inverter 70 to be positioned closer to the outer surface 2c of the motor 2, thereby enabling miniaturization of the drive unit 100.

[0063] In the second inverter 80 of this embodiment, the second capacitor 82 is located below (-D2) the second power module 81. The dimension of the second capacitor 82 in the third direction D3 is smaller than the dimension of the second heat sink 83 in the third direction D3. The second capacitor 82 is positioned to overlap the second power module 81, offset to the other side in the third direction (-D3) when viewed from the second direction D2. The second inverter 80 of this embodiment is positioned above the motor 2 and on the other side in the third direction (-D3) along the outer circumferential surface 2c of the motor 2. Since the outer circumferential surface 2c of the motor 2 is circular when viewed from the first direction D1, the region of the outer circumferential surface 2c of the motor 2 that faces the second inverter 80 slopes downward (-D2) as it moves toward the other side in the third direction (-D3). According to this embodiment, by positioning the second power module 81 in the second inverter 80 towards the other side in the third direction (-D3), the shape of the lower end of the second inverter 80 can be made to conform to the outer circumferential surface 2c of the motor 2. This allows the second inverter 80 to be positioned closer to the outer circumferential surface 2c of the motor 2, thereby enabling miniaturization of the drive unit 100.

[0064] As shown in Figure 3, the drive boards 74 and 84 are located above the power module 71 and are connected to the power module 71. The first drive board 74 controls the opening and closing of the first switching element 71e (see Figure 4). Similarly, the second drive board 84 controls the opening and closing of the second switching element 81e (see Figure 4).

[0065] The control board 7a is connected to the first drive board 74 and the second drive board 84. The control board 7a controls the first inverter 70 and the second inverter 80. More specifically, the control board 7a is connected to the first drive board 74 and the second drive board 84 and instructs the first drive board 74 and the second drive board 84, respectively, on the timing of opening and closing the switches.

[0066] In this embodiment, the control board 7a is located above (+D2) the second inverter 80. Furthermore, the control board 7a in this embodiment is located on the same plane as the first drive board 74. That is, the control board 7a and the first inverter 70 are arranged side-by-side in the third direction D3. As described above, the second inverter 80 is located slightly below (-D2) the first inverter 70. According to this embodiment, by arranging the control board 7a above (+D2) the second inverter 80, the space above (+D2) the second inverter 80 can be effectively utilized, and the drive unit 100 can be miniaturized. Note that the control board 7a does not necessarily have to be located on the same plane as the first drive board 74. In other words, the control board 7a may be located above (+D2) or below (-D2) the first drive board 74.

[0067] As shown in Figure 3, the busbar unit 8 has a plurality of busbars 8a, 8b and a busbar holder 9. That is, the drive device 100 has a plurality of busbars 8a, 8b and a busbar holder 9.

[0068] The busbar holder 9 is made of an insulating resin material. The busbar holder 9 supports a plurality of busbars 8a and 8b. In this embodiment, the busbar holder 9 has a plurality of busbars 8a and 8b embedded inside. That is, the busbar holder 9 is formed by insert molding with a plurality of busbars 8a and 8b arranged inside.

[0069] The multiple busbars 8a and 8b include multiple (three in this embodiment) first busbars 8a and multiple (three in this embodiment) second busbars 8b. The multiple first busbars 8a connect the first inverter 70 to the motor 2. The multiple second busbars 8b connect the second inverter 80 to the motor 2. That is, the multiple busbars 8a and 8b connect the first inverter 70 to the motor 2, and the second inverter 80 to the motor 2, respectively. The three first busbars 8a correspond to the U phase, V phase, and W phase of the motor 2, respectively. Similarly, the three second busbars 8b correspond to the U phase, V phase, and W phase of the motor 2, respectively.

[0070] Each of the multiple busbars 8a and 8b has a first connecting end 8j and a second connecting end 8k. The first connecting end 8j is connected to the first inverter 70 or the second inverter 80. The second connecting end 8k is connected to the first coil end (connection part) 2a of the motor 2. The first connecting ends 8j of the multiple first busbars 8a are arranged side by side in the first direction D1. Similarly, the first connecting ends 8j of the multiple second busbars 8b are arranged side by side in the first direction D1. Furthermore, the second connecting ends 8k of the first busbars 8a and the second busbars 8b are arranged side by side along the third direction above the first coil end 2a and are connected to the first coil end 2a.

[0071] Multiple first busbars 8a protrude from the first inverter 70 to the other side in the third direction (-D3) and further extend to the one side in the first direction (-D1) and connect to the first coil end 2a. Similarly, multiple second busbars 8b protrude from the second inverter 80 to the one side in the third direction (+D3) and further extend to the one side in the first direction (-D1) and connect to the first coil end 2a. For this reason, the first busbars 8a and the second busbars 8b are arranged between the first inverter 70 and the second inverter 80 in the third direction D3.

[0072] Here, the distance in the first direction D1 from the first coil end 2a to the first inverter 70 is defined as the first distance b1. On the other hand, the distance in the first direction D1 from the first coil end 2a to the second inverter 80 is defined as the second distance b2. In this embodiment, the first distance b1 is greater than the second distance b2. This allows space to be provided between the first inverter 70 and the first coil end 2a for the first busbar 8a to be placed, and a portion of the first busbar 8a can be placed between the first inverter 70 and the first coil end 2a. As a result, the concentration of the first coil end 2a and the second coil end 2b between the first inverter 70 and the second inverter 80 can be suppressed. According to this embodiment, it is easier to ensure insulation between the first busbar 8a and the second busbar 8b. On the other hand, by reducing the second distance b2, it becomes easier to shorten the second busbar 8b, which reduces the electrical resistance of the second busbar 8b and makes it easier to improve the driving efficiency of the drive device 100.

[0073] In this embodiment, the case where the first distance b1 is greater than the second distance b2 (b1 > b2) has been described, but the same effect can be obtained even when the second distance b2 is greater than the first distance b1 (b2 > b1). In other words, the first distance b1 and the second distance b2 just need to be different from each other. In particular, it is preferable that the larger of the first distance b1 and the second distance b2 is at least twice the smaller of the other.

[0074] The flow path member 95 is made of, for example, a resin material. The flow path member 95 is connected to the first inverter 70 and the second inverter 80. Inside the flow path member 95, there is a connecting flow path section 91 which is part of the flow path 90. That is, the flow path member 95 is provided with at least a part of the flow path 90. The connecting flow path section 91 connects the first heat sink 73 and the second heat sink 83 in series and allows fluid L to flow from the second heat sink 83 toward the first heat sink 73.

[0075] The configuration of the flow path 90 is not limited as long as it can allow fluid L to flow through the first heat sink 73 and the second heat sink 83. Furthermore, the flow path 90 may branch off midway and be connected in parallel to the first heat sink 73 and the second heat sink 83. In this case, the flow path 90 will rejoin downstream of the first heat sink 73 and the second heat sink 83.

[0076] The flow path 90 in this embodiment has a connecting flow path section 91 that connects the first heat sink 73 and the second heat sink 83. According to this embodiment, the flow path structure between the first heat sink 73 and the second heat sink 83 can be simplified, and the control unit 7 can be miniaturized.

[0077] As shown in Figure 4, the flow channel member 95 has a first end 95a connected to the first heat sink 73 and a second end 95b connected to the second heat sink 83. The flow channel 90 is connected to the first heat sink 73 at the first end 95a and to the second heat sink 83 at the second end 95b.

[0078] The first heat sink 73 and the second heat sink 83 each extend in a first direction D1. The first end 95a is connected to the end of the first heat sink 73 on one side in the first direction (-D1). The second end 95b is connected to the end of the second heat sink 83 on the other side in the first direction (+D1). Therefore, the flow path member 95 extends in the first direction D1 and the third direction D3.

[0079] As shown in Figure 3, the control board 7a is positioned above (+D2) the flow path member 95. In this embodiment, the control board 7a is fixed to the upper surface of the flow path member 95. This reduces the number of components in the control unit 7 compared to the case where a separate member is provided to support the control board 7a, and allows the drive unit 100 to be manufactured at a lower cost. In addition, compared to the case where a separate member is provided to support the control board 7a, the space inside the third housing section 6C can be effectively utilized, allowing the drive unit 100 to be miniaturized.

[0080] In this embodiment, a busbar unit 8 is positioned below (-D2) the flow path member 95. That is, in the second direction D2, the flow path member 95 is positioned between the multiple busbars 8a and 8b and the control board 7a. Therefore, the flow path member 95 can suppress the transfer of heat from the busbars 8a and 8b to the control board 7a, thereby ensuring the reliability of the operation of the control board 7a. Furthermore, when the flow path member 95 is in contact with the busbar unit 8, the fluid L flowing inside the flow path member 95 can cool the busbars 8a and 8b.

[0081] In this embodiment, the flow channel member 95 has a shield portion 95s. The shield portion 95s is located between the plurality of bus bars 8a, 8b and the control board 7a. The shield portion 95s limits the propagation of electromagnetic waves. The shield portion 95s is, for example, a metal film provided on the surface of the flow channel member 95 facing upward (+D2). As an example of the metal film, copper plating can be used. By providing the metal film as the shield portion 95s on the surface facing the control board 7a, it becomes easier to secure the distance between the shield portion 95s and the bus bars 8a, 8b. This makes it easier to ensure insulation between the bus bars 8a, 8b and the shield portion 95s.

[0082] Furthermore, by selecting a material with shielding properties as the material constituting the flow channel member 95, the entire flow channel member 95 may be considered a shield section 95s. In this case, a resin material with carbon fiber or aluminum fiber added can be used as the material constituting the flow channel member 95.

[0083] According to this embodiment, the shielding portion 95s can limit the propagation of electromagnetic waves generated from the busbars 8a and 8b, preventing them from reaching the control board 7a. This prevents the control board 7a from being affected by electromagnetic waves generated from the busbars 8a and 8b, thereby improving the reliability of the control board 7a.

[0084] In this embodiment, the case in which a shield portion 95s is provided on the flow channel member 95 has been described, but the shield portion 95s may be provided independently of the flow channel member 95. For example, a metal plate may be placed between the control board 7a and the flow channel member 95 as the shield portion.

[0085] <Modified Example> Figure 6 is a cross-sectional view of the modified drive unit 200. Compared to the embodiment described above, the modified drive unit 200 differs mainly in the extent to which the components of the control unit 107 are integrated. Components that are the same as those in the embodiment described above are denoted by the same reference numerals, and their descriptions are omitted.

[0086] Similar to the first embodiment, the drive device 200 of this modified embodiment comprises a motor 2, a power transmission mechanism 3, a housing 6, and a control unit 107. The control unit 107 also includes a first inverter 170, a second inverter 180, a flow path member 195, a plurality of bus bars 8a, 8b, a bus bar holder 109, and a control board 7a. In other words, the drive device 200 includes a first inverter 170, a second inverter 180, a flow path member 195, a plurality of bus bars 8a, 8b, a bus bar holder 109, and a control board 7a. The first inverter 170 also includes a first power module 71, a first capacitor 72, a first heat sink 173, and a first drive board 74. Similarly, the second inverter 180 includes a second power module 81, a second capacitor 82, a second heat sink 183, and a second drive board 84.

[0087] In this modified example, the first heatsink 173, the second heatsink 183, the busbar holder 109, and the flow path member 195 are parts of a single integrated member 199. Furthermore, as in the embodiment described above, the first power module 71 and the first capacitor 72 are fixed to the first heatsink 173. The second power module 81 and the second capacitor 82 are fixed to the second heatsink 183. Therefore, the first inverter 70, the second inverter 80, the busbar holder 109, and the flow path member 195 are integrated into one unit.

[0088] According to this embodiment, the assembly process can be completed by arranging a unit integrating the first inverter 70, the second inverter 80, the busbar holder 109, and the flow path member 195 inside the third housing section 6C. In addition, according to this embodiment, integrating the first inverter 70, the second inverter 80, the busbar holder 109, and the flow path member 195 makes it easier to arrange these components without gaps inside the third housing section 6C, thereby enabling miniaturization of the drive unit 200.

[0089] Although embodiments and variations of the present invention have been described above, the configurations and combinations thereof in the embodiments and variations are merely examples, and additions, omissions, substitutions, and other modifications are possible without departing from the spirit of the present invention. Furthermore, the present invention is not limited by the embodiments.

[0090] For example, in the above-described embodiment and its modifications, the components of the first inverter and the second inverter are arranged in the order of drive board, power module, heat sink, and capacitor from top (+D2) to bottom (-D2). However, the arrangement of the components is not limited to this order. For example, the components of the first inverter and the second inverter may be arranged in the order of capacitor, heat sink, power module, and drive board from top (+D2) to bottom (-D2). In this case, by fixing the first inverter and the second inverter to the cover of the third housing, the drive board can be exposed simply by removing the cover, thereby improving maintainability when replacing the drive board.

[0091] Furthermore, this technology can take the following configuration: (1) A drive device comprising: a motor having a rotor that rotates about a central axis; a first inverter and a second inverter arranged along the outer surface of the motor and connected to the motor, respectively; and a fluid passage through which fluid flows, wherein the first inverter has a first power module, a first capacitor, and a first heat sink; the second inverter has a second power module, a second capacitor, and a second heat sink; the fluid passage flows fluid through the first heat sink and the second heat sink, the direction parallel to the central axis is designated as the first direction; the direction perpendicular to the first direction is designated as the second direction; and the direction perpendicular to both the first and second directions is designated as the third direction; the first inverter is positioned on one side of the central axis in the second direction and on one side of the third direction; and the second inverter is positioned on one side of the central axis in the second direction and on the other side of the third direction. (2) The drive device according to (1), wherein the flow path has a connecting flow path portion that connects the first heat sink and the second heat sink. (3) The drive device according to (1) or (2), wherein the first power module and the first capacitor are in contact with the first heat sink, the first heat sink is located between the first power module and the first capacitor, the second power module and the second capacitor are in contact with the second heat sink, and the second heat sink is located between the second power module and the second capacitor. (4) The drive device according to (3), wherein the first capacitor is located on the other side of the first power module in the second direction, the first capacitor is arranged to overlap with the first power module in a position biased to one side of the third direction when viewed from the second direction, the second capacitor is located on the other side of the second power module in the second direction, and the second capacitor is arranged to overlap with the second power module in a position biased to the other side of the third direction when viewed from the second direction.(5) The drive device according to any one of (1) to (4), wherein the first power module, the first capacitor, and the first heatsink are integrated, and the second power module, the second capacitor, and the second heatsink are integrated. (6) The drive device according to any one of (1) to (4), comprising: a plurality of busbars connecting the first inverter and the motor, and the second inverter and the motor, respectively; a busbar holder for holding the busbars; and a flow path member provided with at least a portion of the flow path, wherein the first heatsink, the second heatsink, the busbar holder, and the flow path member are parts of a single member, the first power module and the first capacitor are fixed to the first heatsink, and the second power module and the second capacitor are fixed to the second heatsink. (7) The drive device according to any one of (1) to (6), wherein the first power module has a plurality of first switching elements, the second power module has a plurality of second switching elements, the region in which the plurality of first switching elements are arranged when viewed from the second direction (up and down direction) is defined as the first element arrangement region, the region in which the plurality of second switching elements are arranged when viewed from the second direction (up and down direction) is defined as the second element arrangement region, the dimension of the first element arrangement region in the first direction is greater than the dimension of the first element arrangement region in the third direction, and the dimension of the second element arrangement region in the first direction is greater than the dimension of the second element arrangement region in the third direction. (8) A drive device according to any one of (1) to (7), comprising a plurality of busbars connecting the first inverter and the motor, and the second inverter and the motor, wherein a connection portion is provided at one end of the motor in the first direction to which the plurality of busbars are connected, and the distance in the first direction from the connection portion to the first inverter and the distance in the first direction from the connection portion to the second inverter are different from each other.(9) A drive device according to any one of (1) to (8), comprising: a plurality of busbars connecting the first inverter and the motor, and the second inverter and the motor, respectively; a control board for controlling the first inverter and the second inverter; a flow path member provided with at least a portion of the flow path; the flow path member having a shield portion located between the plurality of busbars and the control board for limiting the propagation of electromagnetic waves.

[0092] 100, 200... Drive unit, 2... Motor, 2a... First coil end (connection part), 2c... Outer surface, 7a... Control board, 8a... First busbar (busbar), 8b... Second busbar (busbar), 9, 109... Busbar holder, 20... Rotor, 70, 170... First inverter, 70a, 80a, 80b... End, 71... First power module, 71e... First switching element, 72... First capacitor, 73, 173...First heat sink, 80, 180...Second inverter, 81...Second power module, 81e...Second switching element, 82...Second capacitor, 83, 183...Second heat sink, 90...Flow channel, 91...Connecting flow channel section, 95, 195...Flow channel member, 95s...Shield section, A1...First element arrangement area, A2...Second element arrangement area, D1...First direction, D2...Second direction, D3...Third direction, J1...Central axis, L...Fluid

Claims

1. A drive device comprising: a motor having a rotor that rotates about a central axis; a first inverter and a second inverter arranged along the outer circumferential surface of the motor and each connected to the motor; and a fluid passage through which fluid flows, wherein the first inverter has a first power module, a first capacitor, and a first heat sink; the second inverter has a second power module, a second capacitor, and a second heat sink; the fluid passage flows fluid through the first heat sink and the second heat sink, with the direction parallel to the central axis being designated as the first direction; the direction perpendicular to the first direction being designated as the second direction; and the direction perpendicular to both the first and second directions being designated as the third direction; the first inverter being positioned on one side of the central axis in the second direction and on one side of the third direction; and the second inverter being positioned on one side of the central axis in the second direction and on the other side of the third direction.

2. The drive device according to claim 1, wherein the flow path has a connecting flow path portion that connects the first heat sink and the second heat sink.

3. The drive device according to claim 1, wherein the first power module and the first capacitor are in contact with the first heatsink, the first heatsink is located between the first power module and the first capacitor, the second power module and the second capacitor are in contact with the second heatsink, and the second heatsink is located between the second power module and the second capacitor.

4. The drive device according to claim 3, wherein the first capacitor is located on the other side of the first power module in the second direction, and the first capacitor is positioned to overlap with the first power module at a position biased toward one side of the first power module in the third direction when viewed from the second direction, and the second capacitor is located on the other side of the second power module in the second direction, and the second capacitor is positioned to overlap with the second power module at a position biased toward the other side of the second power module in the third direction when viewed from the second direction.

5. The drive device according to claim 1, wherein the first power module, the first capacitor, and the first heatsink are integrated, and the second power module, the second capacitor, and the second heatsink are integrated.

6. The drive device according to claim 1, comprising: a plurality of busbars connecting the first inverter and the motor, and the second inverter and the motor, respectively; a busbar holder for holding the busbars; and a flow path member provided with at least a portion of the flow path, wherein the first heat sink, the second heat sink, the busbar holder, and the flow path member are parts of a single member, the first power module and the first capacitor are fixed to the first heat sink, and the second power module and the second capacitor are fixed to the second heat sink.

7. The drive device according to claim 1, wherein the first power module has a plurality of first switching elements, the second power module has a plurality of second switching elements, the region where the plurality of first switching elements are arranged when viewed from the second direction is defined as the first element arrangement region, the region where the plurality of second switching elements are arranged when viewed from the second direction is defined as the second element arrangement region, the dimension of the first element arrangement region in the first direction is greater than the dimension of the first element arrangement region in the third direction, and the dimension of the second element arrangement region in the first direction is greater than the dimension of the second element arrangement region in the third direction.

8. The drive device according to claim 1, comprising a plurality of busbars connecting the first inverter and the motor, and the second inverter and the motor, wherein a connection portion is provided at one end of the motor in the first direction to which the plurality of busbars are connected, and the distance in the first direction from the connection portion to the first inverter and the distance in the first direction from the connection portion to the second inverter are different from each other.

9. The drive device according to claim 1, comprising: a plurality of busbars connecting the first inverter and the motor, and the second inverter and the motor, respectively; a control board for controlling the first inverter and the second inverter; a flow path member provided with at least a portion of the flow path; the flow path member having a shield portion located between the plurality of busbars and the control board for limiting the propagation of electromagnetic waves.

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