Vehicle drive systems

Abstract

To form a heat management system in a vehicle properly with a vehicle drive device serving as the core, and to form the vehicle drive device in a small size.SOLUTION: A vehicle drive device 100 includes: a rotary electric machine MG; a power transmission mechanism GT; an inverter module INV; a power supply module PWR; a refrigerant circuit module 2 constituting at least a part of a refrigerant circuit for circulating a refrigerant for an on-vehicle air conditioner; and a case 9. The case 9 includes: a first accommodation chamber E1 that accommodates the inverter module INV; and a second accommodation chamber E2 that accommodates the rotary electric machine MG and the power transmission mechanism GT. The power supply module PWR is accommodated in the first accommodation chamber E1. The refrigerant circuit module 2 includes an integration unit that is a portion integrated with the case 9. The integration unit includes: a component 21 constituting a part of the case 9; and a component V attached to the case 9.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] Japanese Unexamined Patent Application Publication No. 2019-170077 discloses a vehicle drive device (1) including a rotating electric machine (rotor (20), stator (30)) serving as a driving force source for wheels (803, 804), a drive control device (131) for driving and controlling the rotating electric machine, a charger (136) for charging a battery (805) connected to the rotating electric machine via the drive control device (131) with electric power supplied from an external power source (900), and a case (10) for housing the rotating electric machine, the drive control device (131), and the charger (136). (In the background art, the reference numerals in parentheses are those of the cited document.) In the case (10), a first accommodation chamber for housing the rotating electric machine is formed on the lower side in the vertical direction (Z) in the vehicle-mounted posture in which the vehicle drive device (1) is mounted on the vehicle, and a second accommodation chamber for housing the drive control device (131) and the charger (136) is formed on the upper side. The first accommodation chamber is formed inside a cylindrical peripheral wall portion (10b) of the case (10). The second accommodation chamber is formed as a rectangular box-shaped space inside a rectangular tube-shaped rectangular tube portion (10e) adjacent to the upper side in the vertical direction (Z) of the peripheral wall portion (10b) on the radially outer side of the peripheral wall portion (10b). Further, a cooling portion (60) in which a cooling flow path through which a refrigerant flows along the peripheral wall portion (10b) is formed is formed in the peripheral wall portion (10b).

[0003] The cooling channel formed along the peripheral wall (10b) has an inlet (16) for refrigerant to flow in and an outlet (17) for refrigerant to flow out on the side of the rectangular tube (10e). The drive control device (131) is located on the side of the refrigerant channel closer to the inlet (16), i.e., the upstream side of the refrigerant channel, and the charger (136) is located on the side of the refrigerant channel closer to the outlet (17), i.e., the downstream side of the refrigerant channel. This allows the drive control device (131), which generates heat when driving the rotating electric machine, to be efficiently cooled by the cold refrigerant. Since the battery (805) is charged by an external power supply (900) while the vehicle is stopped, the temperature of the refrigerant does not rise easily due to heat exchange with the drive control device (131), and the charger (136) is properly cooled even though it is located on the downstream side of the refrigerant channel. In addition, reactors (140) and smoothing capacitors (141), which are used to improve the power factor of the power system and stabilize the voltage, are also arranged along the refrigerant flow path and are properly cooled by the refrigerant. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2019-170077 [Overview of the project] [Problems that the invention aims to solve]

[0005] As described above, the vehicle drive system disclosed in the above-mentioned literature is equipped with a cooling structure that can efficiently cool multiple cooling targets. However, vehicles also have other devices that require thermal management, such as air conditioners. The lighter the vehicle's weight, the easier it is to increase the vehicle's energy efficiency, and appropriate heat utilization and waste heat management also contribute to improving the vehicle's energy efficiency. Therefore, it is preferable to make the vehicle drive system, which accounts for a relatively large proportion of the weight of the on-board equipment, compact, and to implement more comprehensive thermal management of the on-board equipment using the vehicle drive system.

[0006] In light of the above background, there is a need for technology that appropriately configures a thermal management system in a vehicle with the vehicle's drive system at its core, as well as technology that enables the vehicle's drive system to be made more compact. [Means for solving the problem]

[0007] A vehicle drive system in view of the above comprises a rotating electric machine equipped with a rotor, an output member driven to a wheel, a power transmission mechanism for transmitting driving force between the rotating electric machine and the output member, an inverter module for controlling the rotation of the rotating electric machine, a power module equipped with a circuit electrically connected to an on-board battery, a refrigerant circuit module constituting at least a part of a refrigerant circuit for circulating refrigerant for an on-board air conditioner, a case comprising a first housing chamber for housing the inverter module, and a second housing chamber for housing the rotating electric machine and the power transmission mechanism, wherein the power module is housed in the first housing chamber, and the refrigerant circuit module comprises an integrated part which is a part integrated with the case, and the integrated part includes a component which constitutes a part of the case and a component which is attached to the case.

[0008] According to this configuration, the vehicle drive unit not only integrates a rotating electric machine and a power transmission mechanism with an inverter module for driving and controlling the rotating electric machine, but also integrates a power supply module and a refrigerant circuit module for the on-board air conditioner with the rotating electric machine and power transmission mechanism. Therefore, the wiring and piping connecting these elements can be kept to a minimum or to a minimum length, making it easier to miniaturize the vehicle drive unit. Furthermore, according to this configuration, not only the rotating electric machine, power transmission mechanism, and inverter module, but also the power supply module are housed in a case, and the refrigerant circuit module has an integrated part that is integrated with the case. Therefore, a vehicle drive unit with many functions and integrated components can be realized, which also makes it easier to miniaturize the vehicle drive unit. In addition, according to this configuration, a thermal management system centered on the vehicle drive unit can be appropriately configured using the components provided in the integrated part of the refrigerant circuit module. Thus, according to this configuration, a thermal management system in the vehicle can be appropriately configured with the vehicle drive unit at its core, and the vehicle drive unit can be made compact.

[0009] Further features and advantages of the vehicle drive system will become clear from the following description of exemplary and non-limiting embodiments, which will be illustrated with reference to the drawings. [Brief explanation of the drawing]

[0010] [Figure 1] Exploded perspective view of a vehicle's drive system [Figure 2] Skeleton diagram of a vehicle drive system [Figure 3] Schematic control block diagram of a vehicle drive system [Figure 4] A schematic diagram showing the refrigerant circuit and cooling water circuit. [Figure 5] Front view of the vehicle drive system as seen from the first side in the front-rear direction. [Figure 6] Rear view of the vehicle's drive unit, seen from the second side in the front-rear direction. [Figure 7] Side view of the vehicle drive unit as seen from the second axial side. [Figure 8]A schematic perspective view showing the arrangement of the cooling unit, inverter module, and power supply module. [Figure 9] A schematic diagram showing an example of the refrigerant flow path in a refrigerant manifold. [Figure 10] Perspective view showing an example of a vehicle drive system configuration. [Figure 11] Exploded perspective view showing an example of a vehicle drive system configuration. [Figure 12] A perspective view showing an example of the configuration of a vehicle drive system, viewed from a different direction than Figure 10. [Figure 13] Figure 11 is an exploded perspective view showing an example of the configuration of a vehicle drive system, viewed from a different direction. [Modes for carrying out the invention]

[0011] The following describes an embodiment of the vehicle drive system with reference to the drawings. The vehicle drive system 100 of this embodiment appropriately configures a thermal management system in the vehicle with the vehicle drive system 100 at its core, while suppressing an increase in size. For example, in small vehicles such as A-segment vehicles in Europe and kei cars in Japan, it is necessary to make onboard components, including the vehicle drive system 100, as small and light as possible to improve mounting efficiency. For example, it is preferable to shorten the length of connecting parts such as wiring and piping by arranging onboard components in close proximity to each other, or to reduce wiring and piping by integrating different devices.

[0012] Furthermore, the coolant used to cool heat-generating devices in a vehicle, such as the drive source for the wheels, is waste heat from the radiator. Generally, the radiator is located at the very front of the vehicle to dissipate heat using the airflow. In small cars such as A-segment vehicles, the drive source for the wheels is often located at the front of the vehicle to ensure sufficient interior space for passengers. In vehicles equipped with air conditioners, the air conditioner, many parts of the refrigerant flow path, and heat exchange components are also located at the front of the vehicle. Regarding heating in particular, in conventional vehicles that used an internal combustion engine as the drive source for the wheels, it was easy to use the internal combustion engine as a heat source. However, in vehicles without an internal combustion engine, such as electric vehicles, there is no such heat source, and heating is exclusively provided by a heat pump system. Compared to systems that use waste heat from an internal combustion engine, the number of installed components tends to increase. By properly piping and wiring these on-board components in the limited space at the front of the vehicle, the usable space for the passenger compartment can be increased. In this embodiment, the vehicle drive unit 100 achieves overall miniaturization, weight reduction, and cost reduction of vehicle-mounted components by integrating functional components that perform thermal management using cooling water or refrigerant with the vehicle drive unit 100.

[0013] The following describes preferred embodiments of such a vehicle drive system 100, but first, we will describe its function as a drive unit for driving the wheels W.

[0014] In the present specification, "driving connection" refers to a state in which two rotating elements are connected so as to be able to transmit a driving force, including a state in which the two rotating elements are connected so as to rotate integrally, or a state in which the two rotating elements are connected so as to be able to transmit a driving force via one or more transmission members. Such transmission members include various members that transmit rotation at the same speed or with speed change, for example, shafts, gear mechanisms, belts, chains, etc. Further, the transmission member may include an engagement device that selectively transmits rotation and driving force, for example, a friction engagement device, a meshing engagement device, etc. However, when referring to "driving connection" for the rotating elements of a planetary gear mechanism, it shall refer to a state in which they are drivingly connected without passing through other rotating elements of the planetary gear mechanism. Also, in the present specification, "rotating integrally" means rotating integrally regardless of whether it is separable or inseparable. That is, a plurality of members that rotate integrally may be integrally formed from the same member, or may be constituted by separate members and integrated by welding, spline connection, etc. Further, in the present specification, regarding the arrangement of two elements, "overlapping in a specific direction view" means that when a virtual straight line parallel to the line-of-sight direction is moved in each direction orthogonal to the virtual straight line, there is at least a part of a region where the virtual straight line intersects both of the two elements.

[0015] As shown in the exploded perspective view of Figure 1 and the skeleton view of Figure 2, the vehicle drive unit 100 comprises a rotating electric machine MG equipped with a rotor 12, an output member driven and connected to a wheel W, and a power transmission mechanism GT that transmits driving force between the rotating electric machine MG and the output member. As will be described later, the direction along the rotation axis A of the rotor 12 is defined as the axial direction L, and the power transmission mechanism GT is positioned on the axial first side L1, which is one side of the axial direction L relative to the rotor 12. As will be described in detail later, the rotating electric machine MG is the driving force source of the vehicle, and the power transmission mechanism GT includes a reduction gear 6 and a differential gear mechanism 5. Specifically, the vehicle drive unit 100 includes a rotating electric machine MG equipped with a rotor 12, a pair of output members each driven and connected to a wheel W, a reduction gear 6 that reduces the rotation of the rotor shaft 13, a differential gear mechanism 5 that distributes the driving force from the rotating electric machine MG transmitted to a differential input element (differential case 50) via the reduction gear 6 to the pair of output members, and a case 9 that forms a housing chamber (second housing chamber E2, described later) that houses the rotating electric machine MG, the reduction gear 6, and the differential gear mechanism 5.

[0016] The pair of wheels W includes a first wheel W1 and a second wheel W2, with the first wheel W1 being driven and connected to a first drive shaft DS1, and the second wheel W2 being driven and connected to a second drive shaft DS2. In this embodiment, the pair of side gears 52, which are the output gears of the differential gear mechanism 5, include a first side gear 53 and a second side gear 54. The first side gear 53 is driven and connected to the first drive shaft DS1 via a connecting shaft J, and the second side gear 54 is driven and connected to the second drive shaft DS2. For example, the first side gear 53 and the connecting shaft J are connected by a spline coupling, and the second side gear 54 and the second drive shaft DS2 are also connected by a spline coupling. These coupling parts are spline engagement parts 59. The output members are, for example, these spline engagement parts 59. Alternatively, the output members may be the first side gear 53, the second side gear 54, the first drive shaft DS1, the second drive shaft DS2, and the connecting shaft J.

[0017] In the following description, as described above, the direction along the rotation axis A of the rotor 12 is defined as the "axial direction L". One side of the axial direction L is defined as the "first axial side L1", and the other side of the axial direction L is defined as the "second axial side L2". In the present embodiment, the rotating electrical machine MG, the reduction gear 6, and the differential gear mechanism 5 are coaxially arranged in the order described from the second axial side L2 toward the first axial side L1. The vehicle drive device 100 of the present embodiment has a single-axis configuration, and the axis (rotation axis A) on which the rotating electrical machine MG, the reduction gear 6, and the differential gear mechanism 5 are arranged is the rotation axis A of the vehicle drive device 100 and is also the rotation axis of the rotating electrical machine MG, the reduction gear 6, and the differential gear mechanism 5. Further, the direction orthogonal to the rotation axis A of the rotor 12 is defined as the "radial direction". In the radial direction, the side closer to the rotation axis A of the rotor 12 is defined as the "radial inner side", and the opposite side is defined as the "radial outer side". Further, in the vehicle-mounted state where the vehicle drive device 100 is mounted on the vehicle, the direction along the vertical direction is defined as the "vertical direction Z", the upper side is defined as the "upper side Z1 of the vertical direction Z", and the lower side is defined as the "lower side Z2 of the vertical direction Z". When the vehicle drive device 100 is horizontally mounted on the vehicle, one of the radial directions coincides with the vertical direction Z. Further, the direction orthogonal to the axial direction L and the vertical direction Z is defined as the "front-rear direction H", one side of the front-rear direction H is defined as the "first front-rear side H1", and the other side is defined as the "second front-rear side H2". In the present embodiment, the first front-rear side H1 is the front side of the vehicle, and the second front-rear side H2 is the rear side of the vehicle.

[0018] Furthermore, in this embodiment, regardless of whether or not the device is mounted on a vehicle, the "opening direction X," "opening surface direction Y," and "specific opening surface direction Ya (first direction)" are defined with respect to the vehicle drive unit 100, as described later. The "opening surface direction Y" is the direction perpendicular to the "opening direction X," and the "specific opening surface direction Ya" is a specific direction within the "opening surface direction Y" and corresponds to the "first direction." When mounted on a vehicle, the "opening direction X" coincides with the "up and down direction Z," and the "specific opening surface direction Ya" coincides with the "forward and backward direction H." Also, the "first opening direction side X1," which is one side of the "opening direction X," coincides with the "upper side Z1 of the up and down direction Z," and the "second opening direction side X2," which is the other side, coincides with the "lower side Z2 of the up and down direction Z." Furthermore, "Specific opening surface direction first side Ya1 (first side of first direction)," which is one side of "Specific opening surface direction Ya (first direction)," coincides with "Front-rear direction first side H1," and "Specific opening surface direction second side Ya2 (second side of first direction)," which is the other side, coincides with "Front-rear direction second side H2." Based on the above, each direction used in the description herein can be interpreted as either the direction when mounted on a vehicle or the direction of the vehicle drive unit 100 alone (direction relative to the vehicle drive unit 100).

[0019] As shown in Figures 1 and 3, the vehicle drive unit 100 further includes an inverter module INV for driving and controlling the rotating electric machine MG, a power module PWR equipped with a circuit electrically connected to the onboard battery BT, and a refrigerant circuit module 2 which constitutes at least a part of the refrigerant circuit 20 (see Figure 4) for circulating refrigerant for the onboard air conditioner. The case 9 includes a first housing chamber E1 for housing the inverter module INV and a second housing chamber E2 for housing the rotating electric machine MG and the power transmission mechanism GT. The power module PWR is housed in the first housing chamber E1. The power module PWR includes at least one of the following circuits electrically connected to the onboard battery BT: a converter 61 (voltage conversion circuit) for converting the voltage of the onboard battery BT, an external charging circuit (charging circuit) for charging the onboard battery BT from an external power source 60, and an external discharge circuit (power supply circuit) for supplying power from the onboard battery BT to the outside. In the example shown in Figure 3, the power module PWR includes all three of these circuits. Here, we illustrate a configuration in which the power module PWR is equipped with a charging circuit 62 (bidirectional charging circuit) that has the functions of both an external charging circuit and an external discharging circuit.

[0020] As shown in Figure 1, the case 9 comprises a case body 90, which is the core housing member of the first housing chamber E1 and the second housing chamber E2, and three cover members (first cover 93, second cover 94, and third cover 95). The case body 90 has a first case section 91 and a second case section 92. The first case section 91 is the part that forms the first housing chamber E1, which houses the inverter module INV and the power supply module PWR. The second case section 92 is the part that forms the second housing chamber E2, which houses the rotating electric machine MG and the power transmission mechanism GT. From the perspective of its function as a drive unit for the wheel W, the power supply module PWR does not necessarily have to be mounted on the vehicle drive unit 100, and in this case, the first case section 91 can also be a case that houses the inverter module INV.

[0021] In this embodiment, the first case portion 91 and the second case portion 92 are shown as being integrally formed from the same material, but the structure of the case 9 is not limited to this. The case 9 may be configured such that the first case portion 91 and the second case portion 92 are made of separate materials and integrated by fastening members such as bolts or welding.

[0022] The first case section 91 is formed in the shape of a rectangular box with an opening at the upper side Z1 in the vertical direction Z when mounted on a vehicle. Here, the direction perpendicular to the opening surface of the first opening 9a, which is the opening of the first case section 91, is defined as the "opening direction X". The first case section 91 has a peripheral wall section 96 that surrounds the first opening 9a and extends along the opening direction X, which coincides with the vertical direction Z when mounted on a vehicle. The first opening 9a is closed by the first cover 93. The first opening 9a corresponds to the opening of the case 9 (first case section 91) that houses the inverter module INV, and the first cover 93 corresponds to a cover that closes this opening (first opening 9a). In addition, the first housing chamber E1 and the second housing chamber E2 are arranged to be aligned in the opening direction X.

[0023] The second case portion 92 is formed in a cylindrical shape with openings on both sides in the axial direction L, and is equipped with a cylindrical peripheral wall portion 97. The cylindrical peripheral wall portion 97 surrounds the power transmission mechanism GT from the radially outer side and corresponds to the portion surrounding the second housing chamber E2 of the case 9. The opening formed on the axial second side L2 is the second opening 9b, and the opening formed on the axial first side L1 is the third opening 9c. The second opening 9b is closed by the second cover 94, and the third opening 9c is closed by the third cover 95. The second cover 94 and the third cover 95 have through holes through which the aforementioned drive shafts (first drive shaft DS1, second drive shaft DS2) pass.

[0024] The rotating electric motor MG functions as a driving force source for a pair of wheels W. As shown in Figure 3, the rotating electric motor MG is electrically connected via an inverter circuit PM to an on-board battery BT, which is a DC power source composed of energy storage devices such as secondary batteries and capacitors. The rotating electric motor MG has the function of a motor that generates power by receiving power from the on-board battery BT, and the function of a generator that generates power by receiving power from the wheels W. The rotating electric motor MG generates driving force by moving using the power stored in the on-board battery BT, and also generates electricity from the driving force transmitted from the pair of wheels W to charge the on-board battery BT. The on-board battery BT is a high-voltage DC power source with a rated voltage of approximately 48 to 400 volts.

[0025] In this embodiment, the on-board battery BT is configured to be charged not only by the power generated by the rotating electric machine MG, but also by power supplied from an external power source 60, such as a commercial power supply with a rating of approximately 100 to 240 volts AC. For this reason, the on-board battery BT is configured to be connectable to the external power source 60 via a charging circuit 62. Figure 3 illustrates a configuration in which the external power source 60 and the charging circuit 62 are connected by a wire, for example, a connector, but the configuration is not limited to this. For example, power may be supplied to the charging circuit 62 from the external power source 60 in a contactless manner by electromagnetic induction or the like. A charging control unit 64 is provided to control the charging circuit 62. In this embodiment, the charging control unit 64 is included in the power module PWR.

[0026] In recent years, it has been proposed to use the on-board batteries BT of electric vehicles and hybrid vehicles as emergency power sources during disasters and other emergencies. To enable the use of on-board batteries BT as such emergency power sources, the charging circuit 62 is configured to have the functions of both an external charging circuit and an external discharge circuit, as described above. Naturally, if the use of such on-board batteries BT is not considered, the charging circuit 62 may be configured to have only the functions of an external charging circuit.

[0027] Furthermore, in this embodiment, the on-board battery BT also supplies power to a low-voltage DC power supply B with a rated voltage of approximately 12 to 24 volts. The low-voltage DC power supply B serves as a power source for auxiliary equipment such as the vehicle's headlights, power windows, power steering, on-board air conditioner, and electric oil pump, as well as for various control devices within the vehicle. Conventionally, in typical vehicles, the low-voltage DC power supply B was charged by electricity generated by an alternator linked to the vehicle's power source (e.g., internal combustion engine). However, in this embodiment, the low-voltage DC power supply B is charged by electricity from the on-board battery BT (high-voltage DC power supply), which has a higher voltage and larger storage capacity than the low-voltage DC power supply B. This eliminates the need to install an alternator, and also suppresses power loss in the vehicle's power source (in this embodiment, the rotating electric machine MG) associated with the operation of the alternator.

[0028] In order to charge the low-voltage DC power supply B with the power from the vehicle battery BT, a converter 61 (voltage conversion circuit) is provided to convert the voltage of the vehicle battery BT. As mentioned above, since the rated voltage of the vehicle battery BT is higher than the rated voltage of the low-voltage DC power supply B, the converter 61 is configured as, for example, a step-down DC / DC converter. DC / DC converters include non-isolated types such as chopper type and charge pump type, and isolated types that use transformers. If it is preferable for the circuit supplied with power from the vehicle battery BT and the circuit supplied with power from the low-voltage DC power supply B to be electrically isolated, then the converter 61 should be of the isolated type. An isolated DC / DC converter is configured with switching elements, and the converter 61 is controlled by a converter control unit 63. In this embodiment, the converter control unit 63 is included in the power supply module PWR.

[0029] Furthermore, some vehicles are equipped with AC power sockets (alternating current power sockets) for supplying power to common household appliances. Such AC power sockets are configured to output alternating current with a rated voltage of 100 to 200 volts. The alternating current power supplied from the AC power socket is generated from the vehicle battery BT using an inverter (not shown). Such an inverter also corresponds to a voltage conversion circuit, and if such an inverter is present, the inverter and the inverter control unit that controls it can also be included in the power module PWR.

[0030] As shown in Figure 2, the rotating electric machine MG comprises a stator 11 fixed to a case 9 and a rotor 12 connected to the rotor shaft 13 so as to rotate integrally with the rotor shaft 13. The rotating electric machine MG is an inner rotor type rotating electric machine, with the rotor 12 positioned radially inward of the stator 11. The rotating electric machine MG is a rotating field type rotating electric machine, and the stator 11 includes a stator core 11a and stator coils 11b wound around the stator core 11a. The rotor 12 includes a rotor core 12a and permanent magnets (not shown) fixed to the rotor core 12a. The rotor shaft 13 is formed in a cylindrical shape coaxial with the rotor core 12a, and a sun gear SG of the planetary gear mechanism constituting the reduction gear 6 is positioned on the outer circumference of the rotor shaft 13 on the first axial side L1 so as to rotate integrally with the rotor shaft 13. As will be described later, the sun gear SG is an input element of the reduction gear 6.

[0031] As shown in Figure 3, the rotating electric machine MG is driven and controlled by the rotating electric machine control unit 17 based on the target torque of the rotating electric machine MG, which is set according to a command from the vehicle control device 300, which is a higher-level control device. The rotating electric machine control unit 17 controls the switching of an inverter circuit PM, which is composed of multiple switching elements, to convert power between DC and multi-phase (three-phase in this embodiment) AC in the inverter circuit PM. The operating voltage of the rotating electric machine control unit 17 is approximately 3.3 volts to 5 volts, the input and output voltages of the inverter circuit PM are approximately 48 volts to 400 volts, and the voltage of the switching control signals of the switching elements constituting the inverter circuit PM is approximately 15 volts to 24 volts. For this reason, a driver 18 is provided between the rotating electric machine control unit 17 and the inverter circuit PM to amplify the voltage of the switching control signals output from the rotating electric machine control unit 17, thereby increasing the driving force and supplying it to the inverter circuit PM.

[0032] The inverter circuit PM is composed of multiple switching elements. The inverter circuit PM has multiple sets (three sets in this case) of AC single-phase arms, each consisting of a series circuit of an upper switching element on the DC positive side and a lower switching element on the negative side. Each switching element is equipped with a freewheeling diode with the forward direction being from the negative to the positive side (from the lower side to the upper side). It is preferable to use power semiconductor elements such as IGBTs (Insulated Gate Bipolar Transistors), power MOSFETs (Metal Oxide Semiconductor Field Effect Transistors), SiC-MOSFETs (Silicon Carbide - Metal Oxide Semiconductor FETs), SiC-SITs (SiC - Static Induction Transistors), and GaN-MOSFETs (Gallium Nitride - MOSFETs) as switching elements. In this embodiment, the inverter circuit PM is configured as a power module in which switching elements are integrated together with freewheeling diodes.

[0033] When the rotating electric machine MG is driven, a large current flows through the switching elements constituting the inverter circuit PM, causing the switching elements to generate heat. Therefore, the amount of heat generated by the inverter circuit PM, which is equipped with multiple switching elements, is large. For this reason, in this embodiment, as shown in Figure 8, a cooling unit 38 is provided to cool the switching elements. As will be described later, the cooling unit 38 has a cooling water channel 39 through which cooling water flows. Note that cooling is not limited to a form of direct heat exchange between the part to be cooled and the cooling water, but also includes a form in which heat is exchanged between the part to be cooled and the cooling water via a heat transfer medium such as oil or a heat sink.

[0034] The inverter module INV comprises at least switching elements constituting the inverter circuit PM and a cooling unit 38 for cooling the switching elements. In this embodiment, as shown in Figure 3, the inverter module INV further comprises a rotating electric motor control unit 17 and a driver 18. That is, in this embodiment, the inverter module INV is configured with a rotating electric motor control unit 17, a driver 18, an inverter circuit PM, and a cooling unit 38. Of course, the inverter module INV may be configured with only switching elements constituting the inverter circuit PM and a cooling unit 38, without including the rotating electric motor control unit 17 and the driver 18.

[0035] As shown in Figure 3, a DC link capacitor 16 (smoothing capacitor) is provided on the DC side of the inverter circuit PM, that is, between the inverter circuit PM and the vehicle battery BT, to smooth the voltage on the DC side of the inverter circuit PM. The inverter module INV may also include the DC link capacitor 16.

[0036] The rotating electric machine control unit 17 drives and controls the rotating electric machine MG via the inverter circuit PM by performing current feedback control based on the rotational position of the rotor 12 (the magnetic pole position of the permanent magnet), the rotational speed of the rotor 12, and the current flowing through the stator coils 11b of each of the three phases. The rotational position of the rotor 12 is detected by a rotation sensor 14, such as a resolver. The current flowing through the stator coils 11b is detected by a current sensor 15. The current sensor 15 is preferably a non-contact type current sensor installed near a power line, such as a busbar connecting the inverter circuit PM and the stator coils 11b of the rotating electric machine MG, as shown in Figure 8.

[0037] Furthermore, the power module PWR is configured to include at least a converter 61 (voltage conversion circuit) and a charging circuit 62. In this embodiment, as shown in Figure 8, the converter 61 and the charging circuit 62 are configured using a common circuit board. Also in this embodiment, as shown in Figure 3, the power module PWR includes a converter 61, a converter control unit 63, a charging circuit 62, and a charging control unit 64.

[0038] In this embodiment, the rotating electric motor control unit 17 included in the inverter module INV and the converter control unit 63 and charging control unit 64 included in the power supply module PWR are formed on a single identical circuit board to constitute the control board ECU. The control board ECU can also be referred to as an integrated control board in which the functions of multiple control units are integrated.

[0039] In this embodiment, as shown in Figure 8, an inverter circuit PM (switching element), a DC link capacitor 16, a converter 61, and a charging circuit 62 are mounted on the first surface 38a of the cooling unit 38, which is the upper surface of the cooling unit 38. The DC link capacitor 16, which smooths the pulsating DC voltage, generates heat due to the inflow and outflow of current. The converter 61 is equipped with a switching element, and this switching element also generates heat due to the current that flows during switching operation. The charging circuit 62 also generates heat because current supplied from the external power supply 60 flows through it to charge the on-board battery BT. The cooling unit 38 is equipped with a cooling water passage 39 through which cooling water flows, and these heat-generating components are properly cooled by being mounted on the first surface 38a of the cooling unit. The inverter circuit PM generates the most heat and reaches the highest temperature.

[0040] For example, the cooling water passage 39 is formed within the cooling unit 38 such that the part cooling the inverter circuit PM is on the downstream side, that is, the cooling water flows from the power module PWR side to the inverter module INV side. By circulating the cooling water from the low-heat-generating region to the high-heat-generating region, the heat-generating object to be cooled can be appropriately cooled while suppressing the rise in the temperature of the cooling water. Also, when the rotating electric machine MG is running, that is, when the vehicle is in motion, the on-board battery BT is almost never charged from the external power supply 60. While it is possible for power to be supplied non-contact from a power supply device installed on the road while the vehicle is driving, this is not generally put into practical use. Therefore, when the rotating electric machine MG is running, the charging circuit 62 is often stopped. In addition, the current that flows when charging the low-voltage DC power supply B is smaller than the current that flows through the charging circuit 62 when charging the on-board battery BT, and the amount of heat generated is also smaller. For this reason, even if the low-voltage DC power supply B is charged while the rotating electric machine MG is running, the amount of heat generated by the converter 61 is smaller than that of the charging circuit 62. Therefore, even when the cooling water is circulated in this manner, the inverter circuit PM can be properly cooled.

[0041] A driver 18 is positioned on the upper side Z1 (first side X1 in the opening direction) of the inverter circuit PM in the vertical Z direction. The control board ECU is positioned across the rotating electric motor control unit 17, the converter control unit 63, and the charging control unit 64. Generally, the control board ECU is positioned such that, in a vertical view (view in the opening direction), the inverter circuit PM, the driver 18, and the rotating electric motor control unit 17 overlap, the converter 61 and the converter control unit 63 overlap, and the charging circuit 62 and the charging control unit 64 overlap. In this embodiment, as shown in Figures 1 and 8, the power supply module PWR is positioned adjacent to the inverter module INV on the first side L1 in the axial direction. The control board ECU is positioned along the axial direction L, spanning across the rotating electric motor control unit 17, the converter control unit 63, and the charging control unit 64. The control board ECU is positioned between the inverter circuit PM (switching element) and the refrigerant circuit module 2 in the vertical Z direction, as shown in Figure 1.

[0042] As shown in Figure 2, the reducer 6 is configured as a planetary gear mechanism comprising an input element that rotates integrally with the rotor shaft 13, a fixed element fixed to the case 9, an output element that rotates integrally with the differential input element (differential case 50), and planetary gears. This planetary gear mechanism is a composite type planetary gear mechanism comprising one sun gear SG, two ring gears (first ring gear RG1, second ring gear RG2), two planetary gears that rotate integrally (first planetary gear PG1, second planetary gear PG2), and a carrier CR that rotatably supports the two planetary gears. In this embodiment, the first planetary gear PG1 is formed to have a smaller diameter than the second planetary gear PG2.

[0043] The sun gear SG rotates integrally with the rotor 12 and rotor shaft 13. The second ring gear RG2 is fixed to the case 9. The first ring gear RG1 is positioned axially on the first side L1 relative to the second ring gear RG2 and is connected to the differential case 50 so as to rotate integrally with the differential case 50. The second planetary gear PG2 meshes with the sun gear SG and the second ring gear RG2, and the first planetary gear PG1 rotates integrally with the second planetary gear PG2 and also meshes with the first ring gear RG1. In this embodiment, the sun gear SG is the input element, the second ring gear RG2 is the fixed element, and the first ring gear RG1 is the output element. The carrier CR is not connected to any of the rotating or fixed elements.

[0044] The differential gear mechanism 5 is a bevel gear type differential gear mechanism, and each includes a bevel gear pinion gear 51 and side gears 52. The pinion gear 51 is supported by a pinion shaft 55 which is supported by the differential case 50 and is arranged to extend radially. The pinion shaft 55 rotates integrally with the differential case 50, and the pinion gear 51 is configured to rotate freely (rotate) around the pinion shaft 55 and to rotate freely (revolve) around the rotation axis A of the differential case 50. Multiple pinion shafts 55 are arranged radially (for example, in a cross shape) around the rotation axis A of the differential case 50, and a pinion gear 51 is attached to each of the multiple pinion shafts 55. The differential case 50 houses the pinion gear 51, side gears 52, and pinion shafts 55 inside.

[0045] The side gear 52 comprises a first side gear 53 and a second side gear 54, arranged as a pair spaced apart in the axial direction L. The first side gear 53 and the second side gear 54 mesh with each of the multiple pinion gears 51 and are arranged to rotate about the rotation axis A of the differential case 50. As shown in Figure 2, the first side gear 53 is connected to a connecting shaft J that extends along the axial direction L through the radially inward side of the reduction gear 6 and the hollow cylindrical rotor shaft 13. The connecting shaft J is connected to a first drive shaft DS1 which is driven to the first wheel W1, which is the wheel W on the axial second side L2, so as to rotate integrally with it. Therefore, the first side gear 53 is driven to the first wheel W1 via the connecting shaft J. The second side gear 54 is connected to a second drive shaft DS2 which is driven to the second wheel W2, which is the wheel W on the axial first side L1, so as to rotate integrally with it.

[0046] The first drive shaft DS1, the second drive shaft DS2, the connecting shaft J, the first side gear 53, and the second side gear 54, which are driven and connected to the wheel W and rotate integrally with the wheel W, can all be considered rotating members corresponding to output members. The first side gear 53 and the second side gear 54 can be considered both the differential gear mechanism 5 and the output members. The first side gear 53 and the second side gear 54 each have a gear portion that meshes with the pinion gear 51 and a spline engagement portion 59 that is connected to the connecting shaft J and the second drive shaft DS2, respectively. When considered functionally separately, the gear portion corresponds to the rotating member included in the differential gear mechanism 5, and the spline engagement portion 59 corresponds to the output member.

[0047] In such vehicle drive systems 100, the rotating electric motor MG and power transmission mechanism GT are often lubricated (including cooled) with oil, and the vehicle drive system 100 of this embodiment is also lubricated with oil. For example, oil accumulated in an oil reservoir formed on the lower side Z2 of the case 9 is supplied to lubrication targets such as bearings and cooling targets such as the stator coil 11b of the rotating electric motor MG by the oil pump OP (see Figures 4 and 7) and by the gears of the power transmission mechanism GT. The oil passage 40 shown in Figure 4 illustrates a configuration in which oil discharged from the oil pump OP is supplied to the rotating electric motor MG (stator coil 11b, bearings of the rotor shaft 13, etc.) and the power transmission mechanism GT (bearings of each gear, etc.). Naturally, the temperature of the oil used for cooling rises, so an oil cooler OC for cooling the oil is also connected to the oil passage 40. The oil cooler OC cools the oil by exchanging heat with cooling water.

[0048] As described above, the inverter module INV is equipped with a cooling unit 38 that cools the switching elements constituting the inverter circuit PM. Therefore, the vehicle drive unit 100 has a cooling water circuit module 3 that constitutes a cooling water circuit 30 that circulates cooling water through a path passing through the cooling unit 38 and the radiator 37 (onboard radiator). As shown in Figure 4, the cooling water circuit 30 is connected to the radiator 37, the first water pump 36, the cooling unit 38, and the three-way valve 35. The cooling water circuit module 3 includes at least a water channel formed in the case 9 and the cooling unit 38. The cooling water circuit module 3 may also further include the three-way valve 35 and the first water pump 36. The cooling water cooled (heat dissipated) by the radiator 37 is sent to the cooling water circuit 30 by the first water pump 36, absorbs heat from the inverter module INV and the power module PWR in the cooling unit 38, and returns to the radiator 37 via the three-way valve 35 for waste heat.

[0049] As shown in Figure 4, the oil cooler OC described above is also connected to the cooling water circuit 30. The oil cooler OC cools the oil flowing through the oil passage 40 by exchanging heat with the cooling water flowing through the cooling water circuit 30. In addition, a water-cooled condenser 31 (refrigerant heat exchanger) is also connected to the cooling water circuit 30. The water-cooled condenser 31 performs heat exchange between the refrigerant of the vehicle air conditioner and the cooling water to cool the refrigerant, which has become hot.

[0050] The coolant, whose temperature has risen after passing through the cooling unit 38, oil cooler OC, and water-cooled condenser 31, returns to the radiator 37 via the three-way valve 35 for heat dissipation. However, in cold weather or when heat dissipation is not necessary, or conversely, when it is desired to raise the oil temperature with the coolant, or when rapid heating is performed by the vehicle's air conditioner, heat dissipation by the radiator 37 is not required. In such cases, the three-way valve 35 switches the flow path of the coolant so that it circulates without passing through the radiator 37.

[0051] As described above, the water-cooled condenser 31 is connected to the refrigerant circuit 20 through which the refrigerant of the vehicle's air conditioner flows. The refrigerant circuit 20 has two paths: a first path 20a that goes from the water-cooled condenser 31 through the first valve V1 to the evaporator 44 and then to the accumulator 41, and a second path 20b that goes from the water-cooled condenser 31 through the second valve V2 to the accumulator 41, and then returns to the water-cooled condenser 31 via the compressor 42, cabin condenser 43, and third valve V3.

[0052] The evaporator 44 is a core functional component of the air conditioning system. It vaporizes the refrigerant, absorbing heat from the surroundings and releasing cool air into the passenger compartment. The accumulator 41 separates the liquid from the refrigerant, which is a mixture of gas and liquid, and supplies only the gas (refrigerant gas) to the compressor 42. The compressor 42 compresses the relatively low-temperature, low-pressure refrigerant gas to a high-temperature, high-pressure state. The cabin condenser 43 is the heat source for the heat pump heating system and releases the heat condensed by the compressor 42 into the passenger compartment. The refrigerant that leaves the cabin condenser 43 flows to the water-cooled condenser 31 via the third valve V3, which is an expansion valve.

[0053] In this embodiment, the battery heatsink 34 also cools the on-board battery BT by heat exchange with the cooling water, and the cooling water, whose temperature has risen, is cooled by heat exchange with the refrigerant in the chiller 32. For this reason, a third flow path 20c is formed as a path for the refrigerant from the water-cooled condenser 31 through the fourth valve V4 and the chiller 32 to the accumulator 41.

[0054] The chiller 32 is connected to a second cooling water circuit 30B through which the cooling water discharged from the chiller 32 returns to the chiller 32 via the battery heat sink 34 and the second water pump 33. Similar to the water-cooled condenser 31, the chiller 32 performs heat exchange between the cooling water and the refrigerant, removing heat from the cooling water to cool it. The cooling water, whose temperature has risen due to heat exchange with the battery heat sink 34, is cooled in the chiller 32. By providing a second cooling water circuit 30B for cooling the onboard battery BT, and a third flow path 20c for cooling the cooling water flowing through the second cooling water circuit 30B, it becomes easier to relax the input / output current restrictions on the onboard battery BT, even when the current flowing to the onboard battery BT increases and the temperature of the onboard battery BT rises, such as during rapid charging or high-speed driving.

[0055] As described above, the refrigerant circuit 20 includes a first flow path 20a containing the flow path of refrigerant from the water-cooled condenser 31 (refrigerant heat exchanger) to the evaporator 44, a second flow path 20b containing the flow path of refrigerant from the compressor 42 to the water-cooled condenser 31, and a third flow path 20c containing the flow path of refrigerant including the chiller 32. The refrigerant flowing through the first flow path 20a is at a lower temperature than that flowing through the second flow path 20b and the third flow path 20c. Also, the refrigerant flowing through the third flow path 20c is at a lower temperature than that flowing through the second flow path 20b.

[0056] In this embodiment, a portion of the flow path constituting the refrigerant circuit 20 is formed using the first cover 93 of the case 9. Furthermore, as shown in Figures 1 and 5, control valves V (first valve V1, second valve V2, third valve V3, fourth valve V4) that control the flow rate or flow path of the refrigerant in the refrigerant circuit 20 are attached to the first surface 93a of the first cover, which is the surface facing the opposite side (first side X1 in the opening direction (opposite the case side in the opening direction)) from the second side X2 in the opening direction (case side in the opening direction). As shown in Figures 1 and 5 to 7, the refrigerant circuit module 2 is configured with the refrigerant circuit 20 and control valves V formed on the first cover 93. The portion of the first cover 93 in which the refrigerant circuit 20 is formed is referred to as the refrigerant manifold 21.

[0057] Thus, the refrigerant circuit module 2 includes an integrated section which is a part integrated with the case 9, and this integrated section includes a component that constitutes part of the case 9 and a component that is attached to the case 9. Here, the refrigerant manifold 21 and the control valve V, which are integrated with the case 9 (specifically, the first cover 93), correspond to the "integrated section". The refrigerant manifold 21 is a component that constitutes part of the case 9 (specifically, the first cover 93), and the control valve V is a component that is attached to the case 9 (specifically, the first cover 93).

[0058] The refrigerant circuit module 2 is equipped with a water-cooled condenser 31, a chiller 32, and an accumulator 41, which are functional components that constitute the flow path of the refrigerant in the refrigerant circuit 20. The refrigerant circuit module 2 and these functional components together constitute the refrigerant module 1. However, if the vehicle battery BT is not cooled using cooling water, that is, if the third flow path 20c is not formed, the chiller 32 may not be provided. In that case, the refrigerant module 1 may be composed of the refrigerant circuit module 2, the water-cooled condenser 31, and the accumulator 41. Furthermore, the refrigerant circuit module 2 only needs to constitute at least a part of the refrigerant circuit 20 that circulates the refrigerant for the vehicle air conditioner. In addition to the refrigerant manifold 21, the control valve V, and at least a part of the water-cooled condenser 31, chiller 32, and accumulator 41 may also be included in the refrigerant circuit module 2.

[0059] The refrigerant circuit components include a control valve V and functional components, and the functional components include a water-cooled condenser 31, a chiller 32, and an accumulator 41. In this embodiment, although not included in the refrigerant module 1, a compressor 42, a cabin condenser 43, an evaporator 44, and a battery heat sink 34 are also functional components. The second water pump 33 is also a functional component, and if the second water pump 33 is integrally provided with the vehicle drive unit 100, for example as shown in Figure 4, then the second water pump 33 can be included in the refrigerant module 1. The accumulator 41 is included in the refrigerant module 1 when it is attached to the first cover 93, as shown in Figures 1, 5 to 7, and 9, but the accumulator 41 may be located separately from the vehicle drive unit 100 and not included in the refrigerant module 1.

[0060] Of the functional components exemplified above, at least the water-cooled condenser 31 corresponds to a specific functional component included in the refrigerant module 1. In addition, the chiller 32 and accumulator 41, which may constitute the refrigerant module 1 together with the water-cooled condenser 31, also correspond to specific functional components depending on the embodiment.

[0061] As shown in Figure 9, the refrigerant manifold 21 is divided into a first manifold 23 and a second manifold 24. The first manifold 23 and the second manifold 24 are configured to be connectable via a connecting passage 22. As described above, the refrigerant circuit 20 has a first passage 20a through which a relatively low-temperature refrigerant flows, and a second passage 20b through which a relatively high-temperature refrigerant flows. The first passage 20a, which is the refrigerant passage from the water-cooled condenser 31 to the evaporator 44, is mainly formed in the first manifold 23. The second passage 20b, which is the refrigerant passage from the compressor 42 to the water-cooled condenser 31, is mainly formed in the second manifold 24. The first manifold 23 corresponds to the first passage region 20A of the refrigerant circuit 20, and the second manifold 24 corresponds to the second passage region 20B of the refrigerant circuit 20.

[0062] Furthermore, the refrigerant manifold 21 is provided with a connection portion 99 (see also Figures 10 to 13) for piping that connects the refrigerant manifold 21 to functional components that are not integrated with the vehicle drive unit 100, such as the evaporator 44 and the cabin condenser 43. Preferably, similar to the control valve V, the connection portion 99 is formed on the first surface 93a of the first cover 93, which is the surface facing the first side X1 in the opening direction (opposite side from the case side in the opening direction).

[0063] Figure 9 illustrates an example in which the third flow path 20c is formed in the first manifold 23. However, if at least a portion of the third flow path 20c is formed in the refrigerant manifold 21, the third flow path 20c may be formed in either the first manifold 23 or the second manifold 24. Naturally, the third flow path 20c may be formed spanning both the first manifold 23 and the second manifold 24.

[0064] In this embodiment, the first housing chamber E1 and the second housing chamber E2 are formed using a single case body 90. However, for example, the first case body forming the first housing chamber E1 and the second case body forming the second housing chamber E2 may be made of separate components, and the first case body and the second case body may be connected to form a case 9 having the first housing chamber E1 and the second housing chamber E2. The first cover 93 is a cover that closes the first housing chamber E1 which houses the inverter module INV, and the refrigerant circuit module 2 is configured by using the first cover 93 as a refrigerant manifold 21 and attaching a control valve V to the first cover 93. In addition, a refrigerant module 1 is configured by attaching a plurality of refrigerant path components (control valve V, functional components) to the first cover 93. Therefore, it can also be said that the in-vehicle inverter unit 10 is configured with an inverter module INV, a case 9 (first case section 91) housing the inverter module INV, a cover (first cover 93) that closes the opening (first opening 9a) of the case 9, and a refrigerant module 1 that constitutes a refrigerant circuit 20 for circulating refrigerant for the in-vehicle air conditioner.

[0065] As described above, the refrigerant module 1 comprises a refrigerant flow path 29 (see Figure 4), which is the flow path for the refrigerant in the refrigerant circuit 20, and a plurality of functional components that constitute the refrigerant circuit 20 and are connected to each other by the refrigerant flow path 29. The refrigerant flow path 29 is formed inside the first cover 93. As shown in Figures 1 and 7, the first cover 93 has a protrusion 93p that projects from the case 9 in a direction along the opening surface of the first opening 9a (opening surface direction Y). As shown in Figures 1, 5, and 7, a specific functional component, which is at least a part of the plurality of functional components, is attached to the second surface 93b of the first cover (the surface of the first cover 93 facing the case side in the opening direction) of the protrusion 93p and is connected to the refrigerant flow path 29. The power supply module PWR may or may not be housed in the first housing chamber E1.

[0066] According to this embodiment, the refrigerant module 1 can be integrally provided with the inverter module INV, the case 9 for housing the inverter module INV, and the first cover 93. That is, the inverter module INV and the refrigerant module 1 can be integrated. Therefore, compared to the case where the inverter module INV and the refrigerant module 1 are independent, it is easier to reduce the number of parts, and this on-board inverter unit 10 can be easily mounted in relatively small vehicles. In addition, specific functional components of the refrigerant module 1 are attached to the second surface 93b of the first cover. As a result, these specific functional components are arranged on the outside of the first housing chamber E1 in the case 9, alongside the first housing chamber E1. Therefore, while integrating the inverter module INV and the refrigerant module 1, they can be appropriately arranged separately on the inside and outside of the first housing chamber E1. Furthermore, the specific functional components of the refrigerant module 1, the case 9, and the inverter module INV can be arranged on the same side (second side X2 in the opening direction (case side in the opening direction)) with respect to the first cover 93. Therefore, it is possible to integrate the inverter module INV and the refrigerant module 1 while suppressing an increase in the size of the on-board inverter unit 10.

[0067] As described above, the first case portion 91 of case 9 includes a peripheral wall portion 96 that surrounds the first opening 9a (opening of the case) and extends along the opening direction X. In this embodiment, as shown in Figures 1, 7, etc., the protruding portion 93p protrudes from case 9 toward the first side Ya1 (first side of the first direction), which is one side of the specific opening direction Ya (first direction), within the opening surface direction Y, which is the direction along the opening surface of the first opening 9a. The specific functional component is positioned in a location that overlaps with the peripheral wall portion 96 when viewed in the specific opening direction (first direction view) along the specific opening direction Ya (first direction).

[0068] Furthermore, if there are multiple specific functional components, all of them are positioned so as to overlap with the peripheral wall portion 96 when viewed in the direction of a specific opening. For example, as shown in Figures 1 and 5, if the specific functional components include a water-cooled condenser 31, an accumulator 41, and a chiller 32, then all of the water-cooled condenser 31, accumulator 41, and chiller 32 are positioned so as to overlap with the peripheral wall portion 96 when viewed in the direction of a specific opening.

[0069] The peripheral wall portion 96 surrounding the first opening 9a (opening) overlaps with the housing section in the case 9 that houses the inverter module INV in a specific opening plane view (first direction view). Since the inverter module INV is housed in this housing space, the specific functional components of the refrigerant module 1, the case 9, and the inverter module INV can be arranged to overlap each other in a specific opening plane view (first direction view). Therefore, it is easier to suppress the enlargement of the on-board inverter unit 10, for example, in the opening direction X or in a direction perpendicular to the opening direction X and the specific opening plane direction Ya (first direction) (here, the axial direction L). In other words, with this configuration, it is possible to integrate the inverter module INV and the refrigerant module 1 while suppressing the enlargement of the on-board inverter unit 10.

[0070] The vehicle drive unit 100 of this embodiment can be configured to include an on-board inverter unit 10, a rotating electric machine MG, an output member that is driven and connected to a wheel W, and a power transmission mechanism GT that transmits driving force between the rotating electric machine MG and the output member. As described above, the case 9 includes a first housing chamber E1 that houses the inverter module INV and a second housing chamber E2 that houses the rotating electric machine MG and the power transmission mechanism GT. As shown in Figures 1, 5 to 7, the first housing chamber E1 and the second housing chamber E2 are arranged to be aligned in the opening direction X. And, as shown in Figures 1 and 7, the specific functional components are positioned in a location that overlaps with the cylindrical peripheral wall portion 97, which is the portion surrounding the second housing chamber E2 of the case 9, when viewed in the opening direction along the opening direction X.

[0071] A specific functional component is attached to the surface (second surface 93b of the first cover) of the protruding portion 93p of the first cover 93 (cover) that faces the case side in the opening direction. If the specific functional component and the portion of the case 9 surrounding the second housing chamber E2 (cylindrical peripheral wall portion 97) do not overlap when viewed in the opening direction, the protruding portion 93p and the specific functional component will protrude in the direction in which the protruding portion 93p protrudes relative to the portion of the case 9 surrounding the second housing chamber E2 (cylindrical peripheral wall portion 97). In other words, with respect to the outer shape of the case 9, the vehicle drive unit 100 with the specific functional component attached tends to be larger in the direction in which the protruding portion 93p protrudes. With this configuration, since the specific functional component and the portion of the case 9 surrounding the second housing chamber E2 (cylindrical peripheral wall portion 97) overlap when viewed in the opening direction, it is easier to miniaturize the vehicle drive unit 100 in the opening direction compared to the case where they do not overlap.

[0072] As shown in Figures 1 and 7, the cylindrical peripheral wall portion 97, which surrounds the second housing chamber E2 in the second case portion 92, bulges out in the first direction Ya1 (first direction, first side) relative to the first case portion 91 (peripheral wall portion 96 of the first case portion 91). Therefore, between the protruding portion 93p and the cylindrical peripheral wall portion 97, and at least between the specific functional component and the cylindrical peripheral wall portion 97, an external case arrangement region E3 is formed, which is enclosed by the faces of a hypothetical rectangular parallelepiped circumstantial to the vehicle drive unit 100, the specific functional component, and the cylindrical peripheral wall portion 97.

[0073] Furthermore, an oil pump OP and an oil cooler OC may be placed in the external mounting area E3 instead of the three-way valve 35 and the first water pump 36, or in addition to the three-way valve 35 and the first water pump 36. If the oil pump OP is placed inside the case 9, only the oil cooler OC may be placed in the external mounting area E3.

[0074] In the examples shown in Figure 7, and in Figures 10 and 11, the three-way valve 35 and the first water pump 36 are mounted on the outer surface of the second case portion 92 (specifically, the cylindrical peripheral wall portion 97) on the first side H1 in the front-rear direction. That is, the three-way valve 35 and the first water pump 36 are positioned between the second case portion 92 and the radiator 37 in the front-rear direction H. In these examples, the oil pump OP and the oil cooler OC are also positioned inside the case 9. Specifically, the oil pump OP is housed in the second housing chamber E2. Here, the oil pump OP is positioned on the first side H1 and below Z2 in the front-rear direction with respect to the rotation axis A. The oil pump OP is also positioned so as to overlap with the protruding portion 93p when viewed in the vertical direction. The oil cooler OC is housed in the first housing chamber E1. Here, the oil cooler OC is positioned between the inverter module INV and the rotating electric machine MG in the vertical direction Z, and more specifically, between the cooling unit 38 and the rotating electric machine MG in the vertical direction Z.

[0075] Furthermore, the vehicle drive unit 100 of this embodiment further includes an oil cooler OC for cooling the oil contained in the second storage chamber E2, and a cooling water circuit module 3 that constitutes a cooling water circuit 30 that circulates cooling water through a path passing through the oil cooler OC and the radiator 37. In this embodiment, a configuration in which the cooling water circuit module 3 is made up of a three-way valve 35, a first water pump 36, and a cooling unit 38 is illustrated. However, the cooling water circuit module 3 may be configured without going through the cooling unit 38. In addition, specific functional components include a water-cooled condenser 31, which is a refrigerant heat exchanger for cooling the refrigerant by heat exchange between the refrigerant and cooling water for an onboard air conditioner.

[0076] With this configuration, the refrigerant for the vehicle air conditioner flowing through the refrigerant circuit 20 can be cooled by the coolant. The coolant circulates through a path that passes through the radiator 37 (vehicle radiator), so the heat from the refrigerant for the vehicle air conditioner can be discharged outside the vehicle by the radiator 37. Furthermore, with this configuration, such a water-cooled condenser 31 (refrigerant heat exchanger) is integrally fixed to the case 9 via the refrigerant path components. Therefore, the number of pipes and other connections that make up the functional components of the refrigerant circuit 20 can be kept to a minimum or to a minimum length.

[0077] Furthermore, as described above, the functional components include a control valve V that controls the flow rate or path of the refrigerant in the refrigerant circuit 20. Additionally, specific functional components may include an accumulator 41 for separating the refrigerant into liquid and gaseous states. The control valve V is mounted on the surface (first surface 93a of the first cover) of the first cover 93 (cover) that faces away from the second side X2 (case side in the opening direction). The water-cooled condenser 31 (refrigerant heat exchanger) and the accumulator 41 are arranged along the wall (peripheral wall 96) surrounding the first housing chamber E1 of the case 9.

[0078] By mounting the control valve V on the surface (first surface 93a) of the first cover 93 (cover) that faces away from the second side X2 (case side in the opening direction), the control valve V and specific functional components can be placed relatively close together, for example, with the first cover 93 (cover) in between. Furthermore, by arranging multiple specific functional components along the wall portion (peripheral wall portion 96), these multiple specific functional components can be efficiently arranged. Therefore, with this configuration, multiple functional components of the refrigerant module 1 can be appropriately arranged while suppressing an increase in the size of the vehicle drive unit 100.

[0079] As described above, in this embodiment, a power module PWR, which includes a circuit electrically connected to the on-board battery BT, is also housed in the first housing chamber E1 together with the inverter module INV. In this case, the on-board inverter unit 10 described above may include the power module PWR.

[0080] Specifically, the vehicle drive unit 100 includes a rotating electric machine MG equipped with a rotor 12, an output member driven and connected to a wheel W, a power transmission mechanism GT that transmits driving force between the rotating electric machine MG and the output member, an inverter module INV for driving and controlling the rotating electric machine MG, a power module PWR equipped with a circuit electrically connected to an on-board battery BT, a refrigerant circuit module 2 that constitutes at least a part of a refrigerant circuit 20 for circulating refrigerant for an on-board air conditioner, and a case 9 having a first housing chamber E1 that houses the inverter module INV and the power module PWR, and a second housing chamber E2 that houses the rotating electric machine MG and the power transmission mechanism GT. As shown in Figures 1 and 2, the power transmission mechanism GT is positioned on the first axial side L1 with respect to the rotor 12. The inverter module INV includes switching elements that constitute the inverter circuit PM and a cooling unit 38 that cools the switching elements.

[0081] As shown in Figures 1, 5, and 6, the inverter module INV is located above the rotating electric machine MG (Z1) and overlaps with the rotating electric machine MG in a vertical view along the vertical direction Z. Also, as shown in Figures 1, 5, 6, 8, and 9, the power supply module PWR is located adjacent to the inverter module INV on the first axial side L1. The refrigerant circuit module 2 is located above the inverter module INV and the power supply module PWR (Z1) in the vertical direction Z and overlaps with the inverter module INV and the power supply module PWR in a vertical view, as shown in Figures 1, 5, 6, and 7. Furthermore, the refrigerant circuit module 2 is integrally fixed to the case 9, as shown in Figures 5 to 7.

[0082] Furthermore, as shown in Figures 1, 5, and 6, the power module PWR is located above the power transmission mechanism GT, Z1, and is positioned in a location that overlaps with the power transmission mechanism GT when viewed in the vertical direction along the vertical direction Z.

[0083] In this embodiment, the vehicle drive unit 100 not only integrates an inverter module INV for driving and controlling the rotating electric machine MG into a drive unit including a rotating electric machine MG and a power transmission mechanism GT, but also integrates a power supply module PWR and a refrigerant circuit module 2 for an on-board air conditioner into the drive unit. Therefore, the wiring and piping connecting the drive unit and inverter module INV to the power supply module PWR and refrigerant circuit module 2 can be kept to a minimum or to a minimum length, and by integrating the case 9 that houses or supports these components, it is easier to miniaturize the entire vehicle drive unit 100, which has many functions. Furthermore, with this configuration, the inverter module INV equipped with a cooling unit 38 is positioned on the upper side Z1 of the rotating electric machine MG, which generates a large amount of heat because a large current flows through the stator coil 11b, and the power supply module PWR is positioned adjacent to the inverter module INV on the axial first side L1, that is, on the side where the power transmission mechanism GT is positioned relative to the rotating electric machine MG. The refrigerant circuit module 2 is positioned above the inverter module INV and the power supply module PWR at Z1. The transfer of heat generated by the rotating electric machine MG to the refrigerant circuit module 2 is inhibited by the inverter module INV and the power supply module PWR, which are equipped with cooling units 38. Therefore, the impact on the refrigerant circuit module 2 from the heat generated by the rotating electric machine MG is easily minimized. Thus, it is easier to appropriately configure a thermal management system in the vehicle with the vehicle drive unit 100 at its core.

[0084] Furthermore, as shown in Figure 4, the vehicle drive unit 100 further includes an oil cooler OC for cooling the oil contained in the second storage chamber E2, and a cooling water circuit module 3 which constitutes a cooling water circuit 30 that circulates cooling water through a path between the oil cooler OC and the radiator 37 (onboard radiator). The refrigerant circuit module 2 also includes a refrigerant manifold 21 (refrigerant path component) which constitutes the flow path of the refrigerant in the refrigerant circuit 20, and a control valve V attached to the refrigerant manifold 21. The refrigerant manifold 21 is further equipped with a water-cooled condenser 31 (refrigerant heat exchanger) for cooling the refrigerant by heat exchange between the refrigerant and the cooling water, as a functional component constituting the refrigerant circuit 20.

[0085] With this configuration, the refrigerant for the vehicle air conditioner flowing through the refrigerant circuit 20 can be cooled by the coolant. The coolant circulates through a path that passes through the radiator 37 (vehicle radiator), so the heat from the refrigerant for the vehicle air conditioner can be discharged outside the vehicle by the radiator 37. Furthermore, with this configuration, such a water-cooled condenser 31 (refrigerant heat exchanger) is integrally fixed to the case 9 via the refrigerant manifold 21 (refrigerant path component). Therefore, the number or length of piping connecting the functional components that make up the refrigerant circuit 20 can be kept to a minimum.

[0086] As described above with reference to Figures 4 and 9, in this embodiment, the refrigerant circuit 20 includes a first flow path region 20A, which is the flow path for the refrigerant from the water-cooled condenser 31 (refrigerant heat exchanger) to the evaporator 44, and a second flow path region 20B, which is the flow path for the refrigerant from the compressor 42 to the water-cooled condenser 31 (refrigerant heat exchanger). The first flow path region 20A is arranged to overlap with the inverter module INV in a vertical view, and the second flow path region 20B is arranged to overlap with the power supply module PWR in a vertical view.

[0087] The switching elements that make up the inverter circuit PM tend to generate heat because large currents flow through them. Therefore, considering heat dissipation, it is preferable that the temperature near these switching elements does not rise. Also, if the inverter module INV includes a control circuit (rotating electric motor control unit 17, driver 18: see Figure 3) that controls the inverter circuit PM, the electronic components that make up this control circuit are often relatively sensitive to heat. Therefore, it is preferable that the temperature near this control circuit does not rise. With this configuration, the first flow path region 20A in the refrigerant circuit 20, which is relatively low temperature, is located close to the inverter module INV, and the second flow path region 20B in the refrigerant circuit 20, which is relatively high temperature, is located close to the power supply module PWR. Therefore, it is possible to prevent heat from the refrigerant circuit module 2 from being transferred to the switching elements that make up the inverter circuit PM and to the control circuit of the inverter circuit PM in the inverter module INV.

[0088] As described above with reference to Figure 4, the refrigerant circuit 20 is equipped with an accumulator 41 for separating the refrigerant into liquid and gas. As shown in Figures 1, 7, and 9, the water-cooled condenser 31 (refrigerant heat exchanger) and the accumulator 41 do not overlap with the inverter module INV and the power supply module PWR in a vertical view, and as shown in Figure 7, they are positioned in a location where their arrangement area in the vertical Z direction overlaps with that of the inverter module INV and the power supply module PWR.

[0089] Among the components that make up the refrigerant circuit 20, the water-cooled condenser 31 (refrigerant heat exchanger) and the accumulator 41 tend to be relatively large. With this configuration, such a water-cooled condenser 31 (refrigerant heat exchanger) and accumulator 41 can be arranged horizontally (here, in the front-to-back direction H) alongside the inverter module INV and the power supply module PWR. Therefore, it is easier to reduce the vertical dimension Z of the vehicle drive unit 100.

[0090] As described above with reference to Figure 4, in this embodiment, the refrigerant circuit 20 includes a chiller 32, which is a heat exchanger for cooling water, for cooling the cooling water flowing through the second cooling water circuit 30B by heat exchange between the cooling water and the refrigerant. As shown in Figures 1, 7, and 9, the chiller 32 does not overlap with the inverter module INV and the power module PWR in a vertical view, and as shown in Figure 7, it is positioned so that its arrangement area in the vertical direction Z overlaps with that of the inverter module INV and the power module PWR. Among the components constituting the refrigerant circuit 20, the chiller 32 tends to be relatively large. With this configuration, such a chiller 32 can be arranged horizontally (here, in the front-to-back direction H) alongside the inverter module INV and the power module PWR. Therefore, it is easier to reduce the vertical Z dimension of the vehicle drive unit 100.

[0091] Although the detailed routing is omitted, as shown in Figures 1 and 8, the cooling unit 38 is equipped with a cooling water passage 39 through which cooling water flows. The switching elements constituting the inverter circuit PM are mounted on the first surface 38a of the cooling unit, which is the upper surface of the cooling unit 38. The control board ECU that controls the inverter circuit PM is positioned between the switching elements and the refrigerant circuit module 2 in the vertical direction Z.

[0092] The switching elements that make up the inverter circuit PM tend to generate heat because large currents flow through them. Also, the electronic components that make up the control circuit that controls the inverter circuit PM, which are mounted on the control board ECU that controls the inverter circuit PM, are often relatively sensitive to heat. With this configuration, the cooling unit 38 allows the switching elements and the control board ECU to be placed in a location where heat from the rotating electric machine MG is less likely to be transferred. The switching elements mounted on the upper surface of the cooling unit 38 (first surface 38a of the cooling unit) are properly cooled by the cooling unit 38, and heat from the rotating electric machine MG is less likely to be transferred to the control board ECU.

[0093] Figures 10 to 13 show an example configuration of the vehicle drive unit 100 described above. Although omitted in Figure 1, etc., as shown in Figures 10 to 13, the vehicle drive unit 100 is supported on the vehicle body (e.g., a cross member) via mounting members 70. The mounting members 70 are connected to the case 9 via mounting brackets 71. In this example, the vehicle drive unit 100 is supported on the vehicle body via three mounting members 70: two mounting members 70 spaced apart in the axial direction L, and a mounting member 70 located below these two mounting members 70 on a Z2 side. One mounting member 70 is connected to the first case portion 91 from the first axial side L1 via a mounting bracket 71, another mounting member 70 is connected to the first case portion 91 from the second axial side L2 via a mounting bracket 71, and the remaining mounting member 70 is connected to the second case portion 92 from the lower side Z2 via a mounting bracket 71.

[0094] As shown in Figures 12 and 13, the case 9 (specifically, the first case portion 91) is provided with connectors 67 for electrically connecting cables (not shown) located outside the case 9 to the inverter module INV, the power supply module PWR, or the control board ECU. Here, the connectors 67 are positioned in through holes formed in the wall portion of the second side H2 in the front-rear direction of the first case portion 91 (specifically, the peripheral wall portion 96). In the illustrated example, multiple connectors 67 (specifically, five connectors 67) are arranged in a line along the axial direction L. For example, cables for transmitting control signals to the control board ECU, cables for supplying power to the control board ECU, cables for supplying power to the inverter circuit PM, and cables for supplying power to the charging circuit 62 are connected to the connectors 67.

[0095] [Other Embodiments] Other embodiments will be described below. Note that the configurations of each embodiment described below are not limited to being applied independently, but can also be applied in combination with the configurations of other embodiments, as long as no inconsistencies arise.

[0096] (1) In the above, an example was given of a power transmission mechanism GT comprising a reduction gear 6 and a differential gear mechanism 5. However, the power transmission mechanism GT is not limited to this configuration. For example, the power transmission mechanism GT may comprise only the differential gear mechanism 5 without the reduction gear 6. Alternatively, the power transmission mechanism GT may comprise only the reduction gear 6 without the differential gear mechanism 5, and transmit power from one rotating electric machine MG to one wheel W. Furthermore, in this embodiment, a planetary gear mechanism with a fixed gear ratio was given as an example of the reduction gear 6, but the reduction gear 6 may have multiple gear ratios.

[0097] (2) As shown in Figure 8, in a configuration where the DC link capacitor 16 is arranged on the first surface 38a of the cooling unit, next to the inverter circuit PM, the inverter module INV may include the DC link capacitor 16. However, for example, if the DC link capacitor 16 is arranged on the back side of the cooling unit 38 (the side opposite to the first surface 38a of the cooling unit), the inverter module INV may not include the DC link capacitor 16. For example, the DC link capacitor 16 may be arranged below the cooling unit 38 Z2, in a position that overlaps with the power transmission mechanism GT in a vertical view. The DC link capacitor 16 is a relatively heat-resistant component, and by arranging such a component on the side of the power transmission mechanism GT, which is closer to the rotating electric machine MG than the cooling unit 38 in the vertical Z direction and further away from the rotating electric machine MG in the axial L direction, the space below the cooling unit 38 Z2 can be effectively utilized, making it easier to miniaturize the entire vehicle drive unit 100.

[0098] Furthermore, it is preferable that the in-vehicle inverter unit 10 includes the DC link capacitor 16, regardless of the placement position of the DC link capacitor 16.

[0099] (3) When both the converter 61 and the charging circuit 62 provided in the power module PWR are of the transformer type, it is preferable to share the transformer components, which tend to be large. Also, like the DC link capacitor 16, the transformer is a component that is relatively resistant to heat. Therefore, it is preferable that the transformer is also located below the cooling unit 38 Z2 and in a position that overlaps with the power transmission mechanism GT in a vertical view. By effectively utilizing the space below the cooling unit 38 Z2 in this way, it is easier to miniaturize the entire vehicle drive unit 100. In the example shown in Figures 11 and 13, the capacitor 66 provided in the power module PWR is located above the cooling unit 38 Z1, and the transformer 65 provided in the power module PWR is located below the cooling unit 38 Z2.

[0100] (4) In the above description, as shown in Figure 5, etc., the refrigerant circuit module 2, which is located above Z1 in the vertical direction Z with respect to the inverter module INV and the power supply module PWR, is configured to include a refrigerant manifold 21 (refrigerant path component) that constitutes the flow path of the refrigerant in the refrigerant circuit 20, and a control valve V attached to the refrigerant manifold 21, and the water-cooled condenser 31 (refrigerant heat exchanger) is not included in the refrigerant circuit module 2 but is attached to the second surface 93b of the first cover on the lower side Z2 of the refrigerant manifold 21. However, if the water-cooled condenser 31 is attached to the first surface 93a of the first cover on the upper side Z1 of the refrigerant manifold 21, similar to the control valve V, the water-cooled condenser 31 may be included in the refrigerant circuit module 2.

[0101] (5) In the above example, the refrigerant flow path 29 is formed inside the first cover 93 as a refrigerant manifold 21. Naturally, it is not necessary for almost the entire refrigerant flow path 29 to be formed inside the first cover 93, and a part of the refrigerant flow path 29 may be formed using other components of the case 9 or piping made of components other than the case 9.

[0102] (6) In the above description, an example was given in which the protruding portion 93p of the first cover 93 protrudes from the case 9 toward the first side Ya1 (first side of the first direction), which is one side in the specific opening surface direction Ya (first direction). However, the protruding portion 93p may be formed to protrude toward multiple directions in the opening surface direction Y. In the above description, an example was given in which the protruding portion 93p protrudes toward the outside of the first opening 9a from one side (face) of the first case portion 91 which is formed in the shape of a rectangular box. However, the protruding portion 93p may be formed to protrude toward the outside of the first opening 9a from multiple sides of the first case portion 91.

[0103] (7) In the above description, the specific functional component, which is at least some of the multiple functional components attached to the surface (second surface 93b of the first cover) facing the second side X2 (case side in the opening direction) of the protruding portion 93p and connected to the refrigerant flow path 29, is exemplified as a water-cooled condenser 31, an accumulator 41, and a chiller 32. Also in the above description, the example given is that all control valves V are located on the surface (first surface 93a of the first cover) facing the first side X1 in the opening direction of the protruding portion 93p. However, at least some of these control valves V may be included in the specific functional component, and the control valves V may be attached to the second surface 93b of the first cover. [Explanation of symbols]

[0104] 2: Refrigerant circuit module, 9: Case, 12: Rotor, 20: Refrigerant circuit, 21: Refrigerant manifold (integrated part, component that forms part of the case), 52: Side gear (output component), 53: First side gear (output component), 54: Second side gear (output component), 59: Spline engagement part (output component), 61: Converter (circuit electrically connected to the vehicle battery), 62: Charging circuit (circuit electrically connected to the vehicle battery), 100: Vehicle drive system, BT: Vehicle battery, DS1: First drive shaft (output component), DS2: Second drive shaft (output component), E1: First housing chamber, E2: Second housing chamber, GT: Power transmission mechanism, INV: Inverter module, J: Connecting shaft (output component), MG: Rotating electric machine, PWR: Power module, V: Control valve (integrated part, component attached to the case), W: Wheel

Claims

[Claim 1] A rotating electric machine equipped with a rotor, An output member that is driven and connected to the wheel, A power transmission mechanism that transmits driving force between the rotating electric machine and the output member, An inverter module for driving and controlling the aforementioned rotating electric machine, A power module equipped with a circuit that is electrically connected to the vehicle battery, A refrigerant circuit module that constitutes at least a part of a refrigerant circuit for circulating refrigerant for an in-vehicle air conditioner, The case comprises a first housing chamber for housing the inverter module and a second housing chamber for housing the rotating electric machine and the power transmission mechanism, The power module is housed in the first housing chamber, The refrigerant circuit module includes an integrated section which is a part that is integrated with the case, The integrated portion includes a component that constitutes part of the case and a component attached to the case, wherein the integrated portion is a vehicle drive device.

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