Drive device

Abstract

This drive device is provided with a rotary electric machine (2), an inverter device (5), and a case (7) that accommodates the rotary electric machine (2) and the inverter device (5). The inverter device (5) is provided with: a power module (51); a connection terminal (56) that is connected to the rotary electric machine (2); a first bus bar (55) that connects the power module (51) and the connection terminal (56); and a current sensor (57). A first cooling water channel (8A) is provided in the case (7) so as to cool the first bus bar (55), the current sensor (57), and the connection terminal (56).

Description

Drive unit

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

[0002] A drive device including a rotating electric machine, an inverter device that controls the rotating electric machine, and a case that houses the rotating electric machine and the inverter device is used. An example of such a drive device is disclosed in, for example, International Publication No. 2023 / 095753 (Patent Document 1).

[0003] The inverter device (inverter device 90) includes a power module (power module PM) including switching elements. The switching elements generate heat during switching operations, which causes the power module to easily rise in temperature. When the power module reaches its heat-resistant temperature, the inverter device imposes an output limit to protect the power module, making it impossible to continuously operate the rotating electric machine (rotating electric machine 2). For this reason, it is necessary to appropriately cool the power module so that it does not reach its heat-resistant temperature.

[0004] In this regard, in the drive device of Patent Document 1, the cooling water passage through which the cooling water flows is formed along the power module and then directed from the power module to the rotating electrical machine, thereby primarily cooling the power module which generates a large amount of heat.

[0005] International Publication No. 2023 / 095753

[0006] However, even if cooling of the power module is focused, other components included in the inverter device may reach their heat resistance temperature first. As a result, it may be necessary to impose output restrictions on the inverter device, which may reduce the continuous operating characteristics of the rotating electric machine.

[0007] Therefore, it is desirable to improve the continuous operation characteristics of the rotating electrical machine in the drive device.

[0008] The drive device according to the present disclosure is a drive device comprising a rotating electric machine, an inverter device that controls the rotating electric machine, and a case that houses the rotating electric machine and the inverter device, wherein the inverter device comprises a power module including a switching element, a connection terminal that is connected to the rotating electric machine, a first bus bar that connects the power module and the connection terminal, and a current sensor that detects the current flowing through the first bus bar, and a first cooling water passage through which cooling water flows is provided in the case so as to cool the first bus bar, the current sensor, and the connection terminal.

[0009] A relatively large current often flows through the first bus bar connecting the power module and the connection terminal, and the first bus bar also tends to heat up. When the temperature of the first bus bar rises, the heat is transferred to the current sensor and the connection terminal, causing them to also rise in temperature. In consideration of this, with the above configuration, the first bus bar, the current sensor, and the connection terminal are cooled by the cooling water flowing through the first cooling water channel, thereby suppressing the temperature rise of these components and making them less likely to reach their heat-resistant temperature. This reduces the likelihood of output limitations being imposed on the inverter device, improving the continuous operation characteristics of the rotating electric machine.

[0010] Further features and advantages of the techniques according to the present disclosure will become more apparent from the following description of exemplary and non-limiting embodiments, which proceeds with reference to the drawings.

[0011] Schematic diagram of a vehicle equipped with a drive device of a first embodiment Schematic diagram of a drive device Schematic diagram of an inverter device Exploded perspective view of the drive device Schematic diagram of a cooling system Plan view of a case body Perspective view of a unit including a resin cover Cross-sectional view of an integrated covering portion of a unit including a resin cover Partial cross-sectional view of a drive device Configuration diagram of a drive device of a second embodiment Flowchart showing a procedure in which a control unit estimates the temperature of coolant at the outlet of a vehicle drive device and controls the opening degree of a first valve During warm-up immediately after starting the vehicle Graph showing the estimated temperature of coolant in each component of a vehicle drive device when the virtual opening degree of the first valve is set to an open state and the temperature of coolant at the outlet of the vehicle drive device is estimated During warm-up immediately after starting the vehicle Estimation of the coolant temperature in each component of a vehicle drive device When the virtual opening degree of the first valve is set to a closed state and the temperature of coolant at the outlet of the vehicle drive device is estimated Graph showing temperature Graph showing estimated temperatures of the coolant at each component of the vehicle drive device when the virtual opening of the first valve is set to an open state and the temperature of the coolant at the outlet of the vehicle drive device is estimated when warming up of the vehicle is complete Graph showing estimated temperatures of the coolant at each component of the vehicle drive device when the virtual opening of the first valve is set to a closed state and the temperature of the coolant at the outlet of the vehicle drive device is estimated when warming up of the vehicle is complete Graph showing estimated temperatures of the coolant at each component of the vehicle drive device when the virtual opening of the first valve is set to an open state and the temperature of the coolant at the outlet of the vehicle drive device is estimated when the vehicle is running Graph showing estimated temperatures of the coolant at each component of the vehicle drive device when the virtual opening of the first valve is set to a closed state and the temperature of the coolant at the outlet of the vehicle drive device is estimated when the vehicle is running

[0012] [First embodiment] A first embodiment of a drive device will be described with reference to the drawings. As shown in Fig. 1, a drive device 1 of this embodiment is mounted on a vehicle VC and used as a vehicle drive device for driving the vehicle VC. The drive device 1 includes a rotating electric machine 2, an inverter device 5 that controls the rotating electric machine 2, and a case 7 that houses the rotating electric machine 2 and the inverter device 5.

[0013] 2 , the drive unit 1 includes a rotating electric machine 2, a pair of output members 4 drivingly connected to wheels W, and a transmission mechanism 3 that transmits driving force between the rotating electric machine 2 and the output members 4. In this embodiment, the transmission mechanism 3 includes a speed change mechanism 31 and a differential gear mechanism 36.

[0014] In this embodiment, the term "rotating electric machine" is used as a concept that includes a motor (electric motor), a generator (electric generator), and a motor-generator that functions as both a motor and a generator as needed.

[0015] Furthermore, "driving connection" refers to a state in which two rotating elements are connected so as to be able to transmit a driving force. This concept includes a state in which two rotating elements are connected so as to rotate integrally, and a state in which 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 (shafts, gear mechanisms, belts, chains, etc.) that transmit rotation at the same speed or at variable speeds, and may also include engagement devices (friction engagement devices, meshing engagement devices, etc.) that selectively transmit rotation and driving force.

[0016] In this embodiment, the rotating electric machine 2 and the speed change mechanism 31 are disposed on a first axis X1. The differential gear mechanism 36 and the pair of output members 4 are disposed on a second axis X2 different from the first axis X1. The first axis X1 and the second axis X2 are parallel to each other, and in this embodiment, the direction parallel to these axes is referred to as the "axial direction L."

[0017] In this embodiment, the direction perpendicular to the axial direction L when viewed in the up-down direction V is referred to as the "width direction C." The up-down direction V refers to the up-down direction when the drive unit 1 is in use. When the drive unit 1 is mounted on a vehicle VC for use as in this embodiment, the up-down direction V coincides with the up-down direction when the drive unit 1 is mounted on the vehicle VC (hereinafter referred to as the "vehicle-mounted state"). In this embodiment, the axial direction L in the vehicle-mounted state coincides with the left-right direction of the vehicle VC, and the width direction C in the vehicle-mounted state coincides with the front-rear direction of the vehicle VC.

[0018] The rotating electric machine 2 includes a stator 21 fixed to a case 7, which is a non-rotating member, and a rotor 27 disposed radially inward of the stator 21 (see FIG. 9 ). The stator 21 includes a stator core 22 and a stator coil 23 (see FIG. 3 ) wound around the stator core 22. The rotating electric machine 2 (stator 21) also includes a coil cover 25 that covers coil end portions 24, which are portions of the stator coil 23 that protrude from the stator core 22 in the axial direction L.

[0019] The coil cover 25 is formed in a doughnut-shaped cap shape, and is fixed so as to abut against the end surface of the stator core 22 in the axial direction L with the coil end portions 24 housed therein. The coil cover 25 covers the coil end portions 24 inside it from the radially inner side, the radially outer side, and the outer side in the axial direction L (the side opposite to the center of the stator core 22).

[0020] The coil cover 25 includes a first coil cover 25A that covers the coil end portions 24 on one side in the axial direction L (in this example, the side on which the rotating electric machine 2 is disposed relative to the speed change mechanism 31; first axial side L1), and a second coil cover 25B that covers the coil end portions 24 on the opposite side in the axial direction L (in this example, the side on which the speed change mechanism 31 is disposed relative to the rotating electric machine 2; second axial side L2). In this embodiment, the first coil cover 25A has a uniform length in the axial direction L, whereas the second coil cover 25B is formed so that its length in the axial direction L is longer in a portion of its circumferential direction than in other portions. The portion of the second coil cover 25B that is longer in the axial direction L is used for connection to the inverter device 5.

[0021] The rotor 27 is rotatably supported radially inside the stator 21. The rotor 27 includes a rotor core and a permanent magnet fixed to the rotor core. The rotor 27 is connected to a rotor shaft 28 so as to rotate integrally with the rotor 27. The rotor shaft 28 serves as an input shaft of the transmission mechanism 3 (speed change mechanism 31).

[0022] The speed change mechanism 31 changes the speed of the output rotation of the rotary electric machine 2 transmitted to the rotor shaft 28. As the speed change mechanism 31, a variety of configurations can be used without particular limitation, such as a configuration including a counter gear mechanism or a configuration including a planetary gear mechanism. In this embodiment having a two-shaft configuration, the rotation after being speed-changed by the speed change mechanism 31 is output from the output gear 32.

[0023] The differential gear mechanism 36 has an input gear 37 that meshes with the output gear 32, and distributes the driving force transmitted from the transmission mechanism 31 to the input gear 37 to the pair of output members 4. Note that the differential gear mechanism 36 can be of various configurations, without particular limitation, such as one that includes a bevel gear pinion and side gear, or one that includes a planetary gear mechanism. The pair of output members 4 are each connected to the wheels W via a drive shaft 45.

[0024] The rotating electric machine 2 is controlled by an inverter device 5. As shown in Figures 3 and 4, the inverter device 5 mainly comprises a power module 51, a capacitor 52, and a control board 59. The inverter device 5 also comprises a power bus bar 53, a connection bus bar 54, a three-phase bus bar 55, connection terminals 56, and a current sensor 57.

[0025] The power module 51 includes a switching element. The power module 51 includes an inverter circuit having a plurality of sets (three sets in this example) of arms for one AC phase, each set being formed by a series circuit of a positive-side upper-stage switching element and a negative-side lower-stage switching element. A freewheel diode is provided adjacent to each switching element, with the forward direction being from the negative electrode to the positive electrode (from the lower stage to the upper stage).

[0026] As the switching element, for example, power semiconductor elements such as an IGBT (Insulated Gate Bipolar Transistor), a power MOSFET (Metal Oxide Semiconductor Field Effect Transistor), a SiC-MOSFET (Silicon Carbide-Metal Oxide Semiconductor FET), a SiC-SIT (SiC-Static Induction Transistor), and a GaN-MOSFET (Gallium Nitride-MOSFET) can be used without any particular restrictions. In this embodiment, the power module 51 is modularized by being resin-molded so as to have a rectangular parallelepiped outer shape (see FIG. 4).

[0027] The power supply bus bar 53 connects the battery B, which is a DC power supply, to the power module 51 (specifically, the switching elements). The power supply bus bar 53 is made of, for example, copper (e.g., tough pitch copper or oxygen-free copper), aluminum, etc. The power supply bus bar 53 includes a positive-side power supply bus bar that connects the positive electrode of the battery B to the upper-stage switching elements of each phase, and a negative-side power supply bus bar that connects the negative electrode of the battery B to the lower-stage switching elements of each phase.

[0028] The battery B here is a high-voltage battery for driving the rotating electric machine 2. As the battery B, for example, a lithium-ion battery, a nickel-metal hydride battery, a lead-acid battery, or the like can be used without any particular restrictions. A capacitor may be used instead of the battery B.

[0029] The capacitor 52 is provided to smooth the DC voltage applied to the power module 51. The capacitor 52 is connected to the power bus bar 53 via the connection bus bar 54. The connection bus bar 54 may also be formed from the same material as the power bus bar 53. The capacitor 52 is connected to each of the positive and negative power bus bars. Note that, as the capacitor 52, for example, an electrolytic capacitor, a film capacitor, a ceramic capacitor, or the like can be used without any particular restrictions. In this embodiment, the capacitor 52 is resin-molded to have a rectangular parallelepiped outer shape and modularized (see FIG. 4).

[0030] The three-phase bus bars 55 connect the power modules 51 and the connection terminals 56. The three-phase bus bars 55 may be formed from the same material as the power supply bus bars 53 and the connection bus bars 54. The three-phase bus bars 55 include a first-phase bus bar, a second-phase bus bar, and a third-phase bus bar that connect the connection points between the upper-stage switching elements and lower-stage switching elements of each phase and the connection terminals 56 of each phase.

[0031] Note that another three-phase bus bar 66 is disposed closer to the rotating electric machine 2 (the stator coil 23 side) than the connection terminal 56, and in relation to this three-phase bus bar 66, the three-phase bus bar 55 can be referred to as an "inverter-side three-phase bus bar." In this embodiment, the three-phase bus bar 55, which is the inverter-side three-phase bus bar, corresponds to the "first bus bar." Furthermore, the three-phase bus bar 66 can be referred to as a "coil-side three-phase bus bar," and the three-phase bus bar 66, which is the coil-side three-phase bus bar, corresponds to the "second bus bar."

[0032] The connection terminals 56 are members that serve as an interface on the rotating electric machine 2 side of the inverter device 5, and are connected to the rotating electric machine 2. The connection terminals 56 may also be formed from the same material as the power supply bus bars 53 and the three-phase bus bars 55. The connection terminals 56 include a first-phase connection terminal, a second-phase connection terminal, and a third-phase connection terminal that correspond to each phase of the three-phase bus bars 55.

[0033] The current sensor 57 detects the current flowing through the three-phase bus bars 55. The current sensor 57 detects the current flowing through the three-phase bus bars 55 of each phase. The current sensor 57 may individually detect the current flowing through the three-phase bus bars 55 of each phase, or may detect the current for two phases individually and calculate the current for the third phase by utilizing the fact that the instantaneous sum of the currents is zero. As the current sensor 57, for example, a Hall sensor, a current transducer, a shunt resistor sensor, etc. can be used without any particular limitation.

[0034] 4 and 7 , the inverter device 5 further includes a resin cover 60, which integrally covers at least a portion of the three-phase bus bar 55, the current sensor 57, and the connection terminal 56. The resin that constitutes the resin cover 60 may be, for example, an epoxy resin, a silicone resin, a urethane resin, or the like, without any particular limitation. By covering the three-phase bus bar 55 and the connection terminal 56 with the resin cover 60, the insulation of these components is appropriately ensured.

[0035] The case 7 accommodates the rotating electric machine 2, the transmission mechanism 3, and the inverter device 5. As shown in Fig. 4 , the case 7 of this embodiment includes a case main body 71 that accommodates the rotating electric machine 2 and the transmission mechanism 3 inside and the inverter device 5 on the outer surface side, and a first cover 78 and a second cover 79 that are joined to the case main body 71 in the axial direction L. The case main body 71 has a rotating electric machine accommodating section 72 that accommodates the rotating electric machine 2, a transmission mechanism accommodating section 73 that accommodates the transmission mechanism 3, and an inverter accommodating section 74 that accommodates the inverter device 5. The rotating electric machine accommodating section 72 and the transmission mechanism accommodating section 73 are formed inside the case main body 71, and the inverter accommodating section 74 is formed outside the case main body 71.

[0036] In this embodiment, the transmission mechanism accommodating portion 73 is formed across the entire area of ​​the case body 71 in the width direction C, whereas the rotating electric machine accommodating portion 72 is formed biased to one side of the case body 71 in the width direction C. In the following description, the side in the width direction C where the rotating electric machine accommodating portion 72 is arranged is referred to as the "first width direction side C1," and the other side in the width direction C opposite thereto is referred to as the "second width direction side C2."

[0037] The inverter accommodating portion 74 is provided on an upper side V1 of the transmission mechanism accommodating portion 73 so as to overlap with the transmission mechanism accommodating portion 73 as viewed in the up-down direction V. The inverter accommodating portion 74 is formed in a substantially L-shape as viewed in the up-down direction V, with a region of constant width on a second width direction side C2 in the width direction C and a region of constant width on a second axial direction side L2 in the axial direction L blending together. The inverter accommodating portion 74 only slightly overlaps with the rotating electric machine accommodating portion 72 as viewed in the up-down direction V, and does not substantially overlap with the rotating electric machine accommodating portion 72.

[0038] 4 and 6 , the inverter accommodating section 74 has a first seat 74A, a second seat 74B, and a through hole 74C on the outer surface of a peripheral wall section 712, which is a main part constituting the case main body 71. The power module 51 constituting the inverter device 5 is fixed to the first seat 74A. A recess is formed in the first seat 74A with an inner surface shape that corresponds to the outer shape of the rectangular parallelepiped power module 51, and the power module 51 is fixed in a state where it fits into the recess with a predetermined gap in the up-down direction V.

[0039] The capacitor 52 constituting the inverter device 5 is fixed to the second pedestal 74B. The second pedestal 74B has a recess formed therein whose inner surface shape corresponds to the outer shape of the rectangular parallelepiped capacitor 52, and the capacitor 52 is fixed in a state of being fitted into the recess with a predetermined gap in the vertical direction V.

[0040] The through-hole 74C is formed in the peripheral wall portion 712 of the case main body 71 at a position that overlaps with the rotating electric machine accommodating portion 72 when viewed in the up-down direction V. The inverter accommodating portion 74 and the rotating electric machine accommodating portion 72 can communicate with each other through the through-hole 74C. The connection terminal 56 is fixed in an oil-tight state to the through-hole 74C, thereby electrically connecting the rotating electric machine 2 and the inverter device 5.

[0041] The case 7 of this embodiment includes an inner case 76 that is separate from the case main body 71 and is disposed inside the case main body 71. The inner case 76 is disposed so as to surround the entire periphery of the stator 21 of the rotating electrical machine 2. In this embodiment, the inner case 76 is in full contact with the outer peripheral surface of the stator 21.

[0042] The first cover 78 is joined to the case body 71 from the first axial side L1. The first cover 78 covers the opening of the case body 71 on the first axial side L1. The second cover 79 is joined to the case body 71 from the second axial side L2. The second cover 79 covers the opening of the case body 71 on the second axial side L2.

[0043] The drive unit 1 of this embodiment is provided with a cooling water passage 8 through which cooling water flows, mainly for cooling the inverter device 5, and a cooling oil passage 9 through which cooling oil flows, mainly for cooling the rotating electrical machine 2. As shown in FIG. 5 , the cooling water passage 8 passes through the case 7 and is provided outside the case 7 to circulate through the battery B, the water pump 110, and the auxiliary equipment 140. Examples of the auxiliary equipment 140 include a heater for heating the interior of the vehicle and a low-voltage battery for supplying power to electrical components. The cooling water passage 8 is also provided to pass through a radiator (e.g., located downstream of the battery B), which is omitted from FIG. 5 , and the cooling water is cooled by the radiator. The cooling oil passage 9 is provided within the case 7 to circulate through the rotating electrical machine 2, the oil pump 120, and the heat exchanger 130.

[0044] In addition, the heat exchanger 130 also passes through the portion of the cooling water passage 8 inside the case 7, and this heat exchanger 130 is configured to exchange heat between the cooling water flowing through the cooling water passage 8 and the cooling oil flowing through the cooling oil passage 9.

[0045] The cooling water passage 8 of this embodiment includes a first cooling water passage 8A, a second cooling water passage 8B, and a third cooling water passage 8C as portions that pass through the case 7. These are arranged in series within the case 7 in the order of the third cooling water passage 8C → the first cooling water passage 8A → the second cooling water passage 8B. The third cooling water passage 8C is a water passage for primarily cooling the power module 51 that constitutes the inverter device 5. The first cooling water passage 8A is a water passage for primarily cooling components other than the power module 51 among the components of the inverter device 5. The second cooling water passage 8B is a water passage for cooling the rotating electrical machine 2, separate from the cooling oil passage 9. The cooling water flowing through the cooling water passage 8 cools the power module 51 → the other components of the inverter device 5 → the rotating electrical machine 2 within the case 7 in this order.

[0046] 5 to 8, the specific configuration of the cooling water passage 8 will be described. The cooling water passage 8 of this embodiment includes a first case inner water passage 81, a first base inner water passage 82, a second case inner water passage 83, a cover inner water passage 84, a third case inner water passage 85, a second base inner water passage 86, a communication water passage 87, a stator outer peripheral water passage 88, and a circulation water passage 89. These are connected in series in the order shown, and the circulation water passage 89 is connected again to the first case inner water passage 81 so that the cooling water can circulate.

[0047] In this embodiment, the first case inner water passage 81 and the first base inner water passage 82 form a third cooling water passage 8C. The cover inner water passage 84, the third case inner water passage 85, the second base inner water passage 86, and the connecting water passage 87 form a first cooling water passage 8A. The stator outer peripheral water passage 88 forms a second cooling water passage 8B. The circulating water passage 89 is provided so as to pass outside the case 7.

[0048] The first case water channel 81 is formed to pass through the outer wall 711 that defines the inverter accommodating section 74 in the case body 71 and to communicate with the recess in the first base 74A. In this embodiment, the first case water channel 81 is formed to communicate with the end of the recess in the first base 74A on the second widthwise side C2.

[0049] The first pedestal water channel 82 is formed in the gap space between the bottom surface of the recess of the first pedestal 74A and the underside of the power module 51 fitted into the recess from the upper side V1. The cooling water flowing through the first pedestal water channel 82 flows along the underside of the power module 51 and cools the power module 51 (specifically, the multiple switching elements included in the power module 51) from the lower side V2. By configuring the cooling water cooled by the radiator to flow along the power module 51 first, it is possible to preferentially cool the power module 51 that generates a large amount of heat. This makes it possible to suppress a temperature rise in the power module 51 and make it difficult for the power module 51 to reach its heat resistance temperature.

[0050] The second case water channel 83 communicates with the recess of the first seat 74A and is formed inside the peripheral wall 712 that separates the transmission mechanism accommodating section 73 and the inverter accommodating section 74 in the case body 71. In this embodiment, the second case water channel 83 is formed to communicate with the end of the recess of the first seat 74A on the first widthwise side C1, which is opposite the connection position with the first case water channel 81. The other end of the second case water channel 83 opens into the peripheral wall 712 at a position offset in the axial direction L and the widthwise direction C from the first seat 74A.

[0051] The in-cover water channel 84 is formed inside the resin cover 60, which integrally covers at least a portion of the three-phase bus bars 55, the current sensors 57, and the connection terminals 56 that constitute the inverter device 5. The resin cover 60 of this embodiment includes a molded portion 60A as a main body that covers at least a portion of the three-phase bus bars 55, the current sensors 57, and the connection terminals 56, and a case portion 60B that holds the molded portion 60A in a fitted state. The molded portion 60A is fixed in a fitted state to the side surface of the case portion 60B, with a predetermined gap in the vertical direction V from the bottom surface of the case portion 60B. The in-cover water channel 84 is formed in the gap space between the bottom surface of the case portion 60B and the underside of the molded portion 60A, which is fitted into the case portion 60B from the upper side V1.

[0052] The resin cover 60 of this embodiment also includes a busbar covering portion 61, an integral covering portion 62, a first water channel forming portion 63, and a second water channel forming portion 64. The busbar covering portion 61 covers a straight portion of the three-phase busbar 55, which extends in an L-shape to connect the power module 51 and the connection terminal 56, on the power module 51 side. The busbar covering portion 61 is formed in a straight line extending along the width direction C. The integral covering portion 62 integrally covers the straight portion of the L-shaped three-phase busbar 55 on the connection terminal 56 side, the current sensor 57, and the connection terminal 56. The integral covering portion 62 is formed to extend along the axial direction L from the first widthwise side C1 of the busbar covering portion 61. The above-mentioned in-cover water channel 84 is also formed in a lower side V2 portion of the integral covering portion 62.

[0053] The first water channel forming portion 63 is formed on the underside V2 of the busbar covering portion 61 in a straight line extending in the width direction C along the busbar covering portion 61. The first water channel forming portion 63 is formed along a portion from near the center of the busbar covering portion 61 to the integrated covering portion 62. The second water channel forming portion 64 is formed in a straight line extending in the width direction C parallel to the first water channel forming portion 63 at a position in the axial direction L different from that of the first water channel forming portion 63. The components of the inverter device 5 are not covered inside the first water channel forming portion 63 and the second water channel forming portion 64, and only the in-cover water channel 84 is formed. The in-cover water channel 84 is formed from the first water channel forming portion 63 to the integrated covering portion 62 to the second water channel forming portion 64.

[0054] The upstream end of the cover in-channel 84 formed in the first channel forming portion 63 is connected to the downstream end of the second case in-channel 83. The downstream end of the cover in-channel 84 formed in the second channel forming portion 64 is connected to the upstream end of the third case in-channel 85.

[0055] The cooling water that has passed through the third cooling water passage 8C (mainly the first pedestal passage 82) flows through the cover passage 84, and this cooling water cools the three-phase bus bar 55, the current sensor 57, and the connection terminal 56. This configuration suppresses temperature increases in the three-phase bus bar 55, the current sensor 57, and the connection terminal 56, making it difficult for them to reach their heat-resistant temperature. In other words, it is difficult for the main components of the inverter device 5, including not only the power module 51 but also the three-phase bus bar 55, the current sensor 57, and the connection terminal 56, to reach their heat-resistant temperature. This reduces the likelihood of output limitations being imposed on the inverter device 5, improving the continuous operation characteristics of the rotating electric machine 2.

[0056] The third case internal water channel 85 is formed to pass through the inside of the peripheral wall portion 712 of the case main body 71 and to communicate with the recess of the second base 74B. In this embodiment, the third case internal water channel 85 is formed to communicate with the end of the recess of the second base 74B on the first width direction side C1.

[0057] The second seat inner water passage 86 is formed in the gap space between the bottom surface of the recess of the second seat 74B and the underside of the condenser 52 fitted into the recess from the upper side V1. The cooling water flowing through the second seat inner water passage 86 flows along the underside of the condenser 52 and cools the condenser 52 from the lower side V2.

[0058] In this embodiment, the cooling water flowing through the first cooling water passage 8A (mainly the water passage 84 inside the cover and the water passage 86 inside the second base) can cool the three-phase bus bar 55, the current sensor 57, and the connection terminal 56, and can also cool the capacitor 52. With this configuration, it is possible to make it difficult for almost all of the components of the inverter device 5, including the power module 51, the three-phase bus bar 55, the current sensor 57, the connection terminal 56, and the capacitor 52, to reach their heat resistance temperature.

[0059] The communication water passage 87 communicates with the recess of the second base 74B and is formed inside the peripheral wall portion 712 of the case body 71. In this embodiment, the communication water passage 87 is formed to communicate with the end of the recess of the second base 74B on the second width direction side C2, which is opposite to the connection position with the third case inner water passage 85. The communication water passage 87 is also formed to pass through the inside of the peripheral wall portion 712 and head toward the inner case 76 that surrounds the stator 21 of the rotating electric machine 2.

[0060] As shown in FIG. 9 , the stator outer circumferential water passage 88 is formed inside the inner case 76. The stator outer circumferential water passage 88 is formed so as to surround the entire periphery of the stator 21 of the rotating electric machine 2. Cooling water that has passed through the first cooling water passage 8A (mainly the cover inner water passage 84 and the second base inner water passage 86) flows through this stator outer circumferential water passage 88, and the stator 21 is cooled by this cooling water. This configuration can also suppress a rise in temperature of the rotating electric machine 2 (stator 21) itself. Therefore, the continuous operation characteristics of the rotating electric machine 2 can be further improved.

[0061] The circulation water passage 89 connects the stator outer circumferential water passage 88 and the first case inner water passage 81. In this embodiment, the circulation water passage 89 passes through a heat exchanger 130, an auxiliary device 140, a battery B, and a water pump 110 on its way from the stator outer circumferential water passage 88 to the first case inner water passage 81. The cooling water is pumped by the water pump 110 and circulates through the cooling water passage 8. The cooling water flowing through the circulation water passage 89 exchanges heat with the cooling oil flowing through the cooling oil passage 9 in the heat exchanger 130, thereby cooling the cooling oil.

[0062] The cooling water flowing through the cooling water passage 8 is heated while cooling the power module 51, the three-phase bus bar 55, the current sensor 57, the connection terminal 56, the capacitor 52, the stator 21, and the cooling oil. This heated cooling water is supplied to the auxiliary device 140, and its heat is utilized by the auxiliary device 140 (for example, when the auxiliary device 140 is a heater for heating the vehicle interior, it is utilized as a heat source). The heated cooling water is also supplied to the battery B, and its heat is utilized to warm up the battery B. Therefore, for example, when the vehicle VC is used in a cold climate, the battery B and the vehicle interior can be quickly warmed. In this embodiment, the heat generation effect is enhanced by recovering heat not only from the power module 51 but also from the three-phase bus bar 55, the current sensor 57, and the connection terminal 56, and the battery B and the vehicle interior can be quickly warmed.

[0063] 5 and 9 , the cooling oil passage 9 of this embodiment includes an in-cover oil passage 91, an in-core oil passage 92, and a circulation oil passage 93. The in-cover oil passage 91 includes a first in-cover oil passage 91A and a second in-cover oil passage 91B. The first in-cover oil passage 91A, the in-core oil passage 92, the first in-cover oil passage 91A, and the circulation oil passage 93 are connected in series in the order listed, and the circulation oil passage 93 is further connected again to the first in-cover oil passage 91A so that the cooling oil can circulate.

[0064] The in-cover oil passage 91 is formed inside the coil cover 25. The in-cover oil passage 91 is formed as an annular oil passage surrounded by the end face of the axial direction L of the stator core 22 and the coil cover 25. The first in-cover oil passage 91A is formed inside the first coil cover 25A on the first axial side L1. The second in-cover oil passage 91B is formed inside the second coil cover 25B on the second axial side L2.

[0065] The in-core oil passage 92 is formed inside the stator core 22. The in-core oil passage 92 is formed to penetrate the stator core 22 in the axial direction L so as to connect the first in-cover oil passage 91A and the second coil cover 25B. It is sufficient that at least one in-core oil passage 92 is formed, but multiple in-core oil passages 92 may be formed and distributed circumferentially.

[0066] The stator core 22 and the coil end portions 24 are cooled by the cooling oil flowing through the in-cover oil passage 91 and the in-core oil passage 92. This, combined with the cooling of the stator 21 by the cooling water flowing through the stator outer circumferential water passage 88, allows the stator 21 to be cooled more efficiently. In particular, the stator 21 can be cooled stably even in situations where oil splattering within the drive device 1 hardly occurs, such as when the vehicle VC is stopped or traveling at a low speed.

[0067] The circulation oil passage 93 connects the second in-cover oil passage 91B and the first in-cover oil passage 91A. In this embodiment, the circulation oil passage 93 passes through an oil pump 120 and a heat exchanger 130 between the second in-cover oil passage 91B and the first in-cover oil passage 91A. The cooling oil is pumped by the oil pump 120 and circulates through the cooling oil passage 9. The cooling oil flowing through the circulation oil passage 93 is cooled by heat exchange with the cooling water flowing through the cooling water passage 8 in the heat exchanger 130.

[0068] In this embodiment, the connection terminals 56 that constitute the inverter device 5 pass from the inverter accommodating portion 74 through the through holes 74C into the rotating electrical machine accommodating portion 72 and then into the interior of the second coil cover 25B. The connection terminals 56 penetrate a portion of the second coil cover 25B that is long in the axial direction L and enter the interior of the second coil cover 25B. The connection terminals 56 are disposed inside the second coil cover 25B, and a three-phase bus bar 66 that connects the connection terminals 56 and the stator coil 23 is also disposed inside the second coil cover 25B.

[0069] With this configuration, the cooling oil flowing through the cooling oil passages 9 (particularly the first inner-cover oil passages 91A) further cools the three-phase bus bars 66 and the connection terminals 56. Furthermore, by cooling the three-phase bus bars 66 and the connection terminals 56, the three-phase bus bars 55 connected to the connection terminals 56 can also be cooled. This makes it possible to further suppress temperature increases in the three-phase bus bars 55 and the connection terminals 56, thereby further improving the continuous operation characteristics of the rotating electric machine 2.

[0070] Other Embodiments of the First Embodiment (1) In the above embodiment, the cooling water flowing through the first cooling water passage 8A cools the three-phase bus bar 55, the current sensor 57, the connection terminal 56, and the capacitor 52. However, the present invention is not limited to such a configuration, and it is sufficient that the cooling water flowing through the first cooling water passage 8A cools at least the three-phase bus bar 55, the current sensor 57, and the connection terminal 56, and it is not necessary for the cooling water to cool the capacitor 52.

[0071] (2) In the above embodiment, the resin cover 60 covers the three-phase bus bars 55, the current sensors 57, and the connection terminals 56. However, the present invention is not limited to such a configuration, and the range covered by the resin cover 60 may be at least a portion of each of the three-phase bus bars 55, the current sensors 57, and the connection terminals 56.

[0072] (3) In the above embodiment, the resin cover 60 has been described with the first water channel forming portion 63 provided only over a range that is approximately half the length of the bus bar covering portion 61. However, the present invention is not limited to such a configuration, and the first water channel forming portion 63 may be provided only over a range that is not part of the length of the bus bar covering portion 61, or may be provided over the entire bus bar covering portion 61. Furthermore, the resin cover 60 may not have the first water channel forming portion 63, and the second case inner water channel 83 may be provided to communicate with the cover inner water channel 84 formed inside the integrated covering portion 62.

[0073] (4) In the above embodiment, the in-cover water channel 84 is formed as a gap space between the bottom surface of the case portion 60B and the lower surface of the molded portion 60A. However, the present invention is not limited to such a configuration. For example, the resin cover 60 may be formed only with the molded portion 60A, and the in-cover water channel 84 may be formed using a core having a shape corresponding to the shape of the water channel when the molded portion 60A is formed. Alternatively, the resin cover 60 may be formed only with the molded portion 60A, and the in-cover water channel 84 may be formed by drilling or the like after the molded portion 60A is formed.

[0074] (5) In the above embodiment, the second cooling water passage 8B (stator outer periphery water passage 88) is formed in the inner case 76, which is separate from the case body 71. However, the present invention is not limited to such a configuration, and the second cooling water passage 8B (stator outer periphery water passage 88) may be formed in the case body 71 in a case where the stator 21 of the rotating electric machine 2 is directly supported by the case body 71.

[0075] (6) In the above embodiment, the rotating electric machine 2 includes the coil cover 25 that covers the coil end portions 24, and the coil end portions 24 are cooled by cooling oil flowing through the oil passages 91 inside the coil cover 25. However, the present invention is not limited to such a configuration, and the rotating electric machine 2 does not need to include such a coil cover 25. In this case, the stator core 22 and the coil end portions 24 may be cooled by oil that is splashed by, for example, the rotation of the rotor 27 while the vehicle VC is running. Similarly, the connection terminals 56 and the three-phase bus bars 66 that are disposed in an exposed state in the rotating electric machine housing portion 72 may also be cooled by splashed oil.

[0076] (7) In the above embodiment, the drive unit 1 is described as having the cooling oil passage 9 provided in addition to the cooling water passage 8. However, the present invention is not limited to such a configuration, and the drive unit 1 is only required to have at least the cooling water passage 8, and is not necessarily required to have the cooling oil passage 9.

[0077] (8) In the above embodiment, a specific arrangement of the components constituting the inverter device 5 is described as an example. However, the arrangement is not limited to this, and the components of the inverter device 5 may be arranged in any desired arrangement.

[0078] (9) In the above embodiment, an example was described in which the cooling water passage 8 is configured by combining a portion formed inside the case 7 and a portion formed inside the resin cover 60. However, without being limited to such a configuration, the entire cooling water passage 8 may be formed inside the case 7, or the entire cooling water passage 8 may be formed inside at least one separate member different from the case 7.

[0079] (10) In the above embodiment, an example was described in which the cooling oil passage 9 is configured by combining a portion formed inside the case 7, a portion formed inside the coil cover 25, and a portion formed inside the stator core 22. However, without being limited to such a configuration, the entire cooling oil passage 9 may be formed inside the case 7, or the entire cooling oil passage 9 may be formed inside at least one separate member different from the case 7.

[0080] (11) In the above embodiment, the cooling water passage 8 may further include a bypass water passage that bypasses the battery B. In this case, for example, when the temperature of the battery B is below a predetermined reference temperature, the cooling water may be supplied to the battery B, and when the temperature of the battery B is equal to or higher than the reference temperature, the cooling water may be switched to flow through the bypass water passage. The bypass water passage may be connected so as to merge between the battery B and the radiator.

[0081] (12) The specific configuration of the transmission mechanism 3 described in the above embodiment is merely an example. The transmission mechanism 3 may have any configuration.

[0082] (13) In the above embodiment, an example has been described in which the technology according to the present disclosure is applied to a vehicle drive device 1. However, the present disclosure is not limited to such a configuration, and can be similarly applied to a drive device 1 for other purposes, not limited to a vehicle.

[0083] (14) The configurations disclosed in the above-described embodiments (including the above-described embodiments and other embodiments; the same applies hereinafter) can be applied in combination with configurations disclosed in other embodiments, as long as no contradiction occurs. Regarding other configurations, the embodiments disclosed in this specification are examples in all respects and can be appropriately modified within the scope of the present disclosure.

[0084] Second Embodiment A second embodiment of the drive device will be described in detail with reference to the drawings. A drive device 1001 of this embodiment is also configured as a vehicle drive device for driving a vehicle 1004.

[0085] [Configuration of Cooling System] As shown in FIG. 10 , a drive device 1001 according to this embodiment (corresponding to the “drive device 1” in the first embodiment) includes an inverter unit 1010 (an example of a drive component, corresponding to the “inverter device 5” in the first embodiment), a motor unit 1030 (an example of a drive component, corresponding to the combination of the “rotating electric machine 2” and the “transmission mechanism 31” in the first embodiment), a transaxle 1050 (corresponding to the “transmission mechanism 3” in the first embodiment), an oil pump 1060 (corresponding to the “oil pump 120” in the first embodiment), an oil cooler 1070 (an example of a drive component, corresponding to the “heat exchanger 130” in the first embodiment), an oil reservoir 1080, a cooling circuit for cooling these components, and a control unit 1090. In the drive device 1001, the cooling circuit includes a coolant flow path 1002 (corresponding to the “cooling water path 8” in the first embodiment) and an oil flow path 1003 (corresponding to the “cooling oil path 9” in the first embodiment). A coolant flows through the coolant flow path 1002, and oil flows through the oil flow path 1003. Examples of the coolant include antifreeze liquids containing ethylene glycol as a main component, long-life coolant (LLC), fluorine-based inert liquids, and other liquids with high electrical insulation properties. The oil flowing through the oil flow path 1003 is, for example, a low-viscosity lubricating oil.

[0086] Each component of the drive device 1001 is controlled by a control unit 1090. The control unit 1090 is, for example, an ECU (Electronic Control Unit). The components include the inverter unit 1010, motor unit 1030, transaxle 1050, oil pump 1060, oil cooler 1070, and oil reservoir 1080, as well as the various parts that make up these components.

[0087] The inverter unit 1010 includes a smoothing capacitor 1011 (corresponding to the "capacitor 52" in the first embodiment), an inverter 1012 (corresponding to the "power module 51" in the first embodiment), a current sensor 1013 (corresponding to the "current sensor 57" in the first embodiment), and a three-phase terminal block 1014 (corresponding to the "connection terminal 56" in the first embodiment). The configuration of the inverter unit 1010 is known, and therefore a detailed description thereof will be omitted.

[0088] The motor unit 1030 includes a traction motor 1031 (corresponding to the "rotating electric machine 2" in the first embodiment) and a gear mechanism that reduces the rotational output of the traction motor 1031. The traction motor 1031 includes a shaft 1032 (corresponding to the "rotor shaft 28" in the first embodiment), a rotor 1033 (corresponding to the "rotor 27" in the first embodiment), a stator 1034 (corresponding to the "stator 21" in the first embodiment), and a case 1035 (corresponding to the "rotating electric machine housing portion 72" in the first embodiment). The shaft 1032 is fixed to the rotor 1033 by a method such as press-fitting. The rotor 1033 has a cylindrical shape, and a cylindrical stator 1034 is disposed radially outside the rotor 1033 so as to surround the rotor 1033. A case 1035 is disposed on the outer circumferential surface of the stator 1034 with a gap therebetween. Coolant flows through this gap to cool the stator 1034. That is, this gap serves as a water jacket 1002c (corresponding to the "stator outer periphery water passage 88" in the first embodiment) and constitutes a part of the coolant flow path 1002.

[0089] A shaft oil passage 1032a is formed in the shaft 1032 of the travel motor 1031, through which oil from the oil passage 1003 flows. That is, the shaft oil passage 1032a is a through-hole formed along the longitudinal direction of the shaft 1032. The travel motor 1031 also has a stator oil passage 1034a (corresponding to the "intra-core oil passage 92" in the first embodiment) through which oil flows inside the stator 1034. In this way, the oil from the oil passage 1003 flows inside the shaft 1032 and the stator 1034, so that the travel motor 1031 is also cooled by the oil. The oil flowing through the oil passage 1003 is also used to lubricate the gear mechanism.

[0090] The transaxle 1050 includes a counter gear 1051 (corresponding to the "speed change mechanism 31" in the first embodiment) and a differential gear 1052 (corresponding to the "differential gear mechanism 36" in the first embodiment). The configuration of the transaxle 1050 is well known, so a detailed description thereof will be omitted.

[0091] [Coolant Flow Path] The coolant flow path 1002 includes piping arranged between the inside and outside of the drive unit 1001, and is a flow path through which the coolant flows. Specifically, the coolant flow path 1002 is configured so that the coolant flows in from outside the drive unit 1001, flows through the inverter unit 1010, the motor unit 1030, the oil sump 1080, and the oil cooler 1070 in this order inside the drive unit 1001, cooling them, and then flows out of the drive unit 1001. Outside the drive unit 1001, the coolant flowing through the coolant flow path 1002 flows through a vehicle 1004 (corresponding to the "vehicle VC" in the first embodiment) and a water pump 1005 (corresponding to the "water pump 110" in the first embodiment) before flowing back into the drive unit 1001. The vehicle 1004 includes a battery, a radiator, and auxiliary devices (none of which are shown), etc.

[0092] A first valve 1002a (an example of a valve) is disposed between the inverter unit 1010 and the motor unit 1030. The first valve 1002a is a three-way valve whose opening is controlled by the control unit 1090 to control the flow direction of the coolant. A flow path for circulating the coolant toward the motor unit 1030 and a flow path for discharging the coolant to the outside of the drive device 1001 are connected to the outlet side of the first valve 1002a. In this embodiment, the control unit 1090 controls the opening of the first valve 1002a so as to switch the flow path of the coolant flowing out of the first valve 1002a between a flow path for circulating the coolant toward the motor unit 1030 and a flow path for discharging the coolant to the outside of the drive device 1001. A flow path disposed on the outlet side of the oil cooler 1070 is connected to the flow path for discharging the coolant to the outside of the drive device 1001, and the flow paths merge.

[0093] A second valve 1002b (an example of a valve), which is a three-way valve that controls the flow direction of the coolant by controlling its opening, is disposed in a flow path connected to the outlet of the coolant flow path 1002 (water jacket 1002c) through which the coolant flows, flowing from the inverter unit 1010 and passing through the first valve 1002a into the traction motor 1031. The second valve 1002b is connected to the outlet side of the second valve 1002b, which is connected to a flow path that flows the coolant toward the oil sump 1080 and a flow path that flows the coolant toward the oil cooler 1070. In this embodiment, the control unit 1090 controls the opening of the second valve 1002b so as to switch the flow path of the coolant flowing out of the second valve 1002b between a flow path that flows toward the oil sump 1080 and a flow path that flows toward the oil cooler 1070. The outlet of the flow path that flows the coolant to the oil sump 1080 is connected to a flow path that flows the coolant to the oil cooler 1070. A flow path connected to the outlet of the oil cooler 1070 is connected to a flow path that allows the coolant to flow out of the drive unit 1001.

[0094] Next, we will explain the flow of coolant in coolant flow path 1002. The coolant flowing through coolant flow path 1002 is pressure-fed by water pump 1005 arranged in a flow path connected to the inlet of drive device 1001, flows into inverter unit 1010 of drive device 1001, flows sequentially through inverter 1012, smoothing capacitor 1011, current sensor 1013, and three-phase terminal block 1014, and exchanges heat with these before flowing out of inverter unit 1010 and flowing into first valve 1002a.

[0095] The first valve 1002a controls (switches) the flow direction of the coolant by the control unit 1090, so that the coolant that flows into the first valve 1002a flows toward the motor unit 1030 or toward the outside of the drive device 1001. For example, when the first valve 1002a is switched so that the coolant flows toward the motor unit 1030, the coolant flows into the water jacket 1002c, which is the gap between the stator 1034 and the case 1035 of the traction motor 1031, and exchanges heat with the stator 1034 as well as with the case 1035.

[0096] The coolant that has flowed through the traction motor 1031 flows out of the motor unit 1030 and into the second valve 1002b. The flow direction of the coolant through the second valve 1002b is also controlled (switched) by the control unit 1090, so that the coolant that has flowed into the second valve 1002b flows toward the oil sump 1080 or toward the oil cooler 1070. For example, when the second valve 1002b is switched so that the coolant flows toward the oil sump 1080, the coolant flows into the oil sump 1080, exchanges heat with the oil stored in the oil sump 1080, and then flows out of the oil sump 1080. The coolant that has flowed out of the oil sump 1080 flows toward the oil cooler 1070. At this time, the oil passage connecting the oil reservoir 1080 and the oil cooler 1070 merges with the oil passage connected to the second valve 1002 b and heading toward the oil cooler 1070 .

[0097] The coolant that flows into oil cooler 1070 flows through oil flow path 1003 and exchanges heat with the oil that has flowed into oil cooler 1070, cooling the oil. This increases the temperature of the coolant. The coolant that flows out of oil cooler 1070 flows out to the outside of drive unit 1001. At this time, the flow path through which the coolant flows out from oil cooler 1070 to the outside of drive unit 1001 is connected to first valve 1002a and merges inside drive unit 1001 with the flow path through which the coolant flows out to the outside of drive unit 1001.

[0098] The coolant that has flowed out of the drive unit 1001 flows through the coolant flow path 1002 , exchanges heat with the radiator and battery of the vehicle 1004 , and returns to the water pump 1005 .

[0099] [Oil Flow Path] The oil flow path 1003 is configured to include piping arranged inside the drive unit 1001, and oil for cooling and lubrication flows through it. Specifically, the oil flow path 1003 is configured so that oil pressure-fed by the oil pump 1060 flows through the oil cooler 1070 and flows into the traction motor 1031 of the motor unit 1030. The oil flow path 1003 branches into two on the inlet side of the traction motor 1031, one oil path being connected to the stator oil path 1034a and the other oil path being connected to the shaft oil path 1032a.

[0100] An outlet of the stator oil passage 1034a is connected to an oil passage that allows oil to flow into an oil pump 1060. In addition, an outlet of the shaft oil passage 1032a is connected to an oil passage that allows oil to flow into an oil reservoir 1080.

[0101] In the oil line that branches off at the inlet side of travel motor 1031 and is connected to shaft oil line 1032a, a third valve 1003a, which is an on-off valve, is disposed between the branch point and shaft oil line 1032a. In addition, the oil line connecting third valve 1003a and shaft oil line 1032a branches off into an oil line that is connected to transaxle 1050. In other words, oil flows into shaft oil line 1032a and transaxle 1050 only when third valve 1003a is open.

[0102] The oil that flows into transaxle 1050 cools and lubricates counter gear 1051 and differential gear 1052 before flowing out of transaxle 1050. An oil passage that allows oil to flow into oil reservoir 1080 is connected to the outlet of transaxle 1050.

[0103] Oil is stored in the oil sump 1080. The oil contains foreign matter such as iron powder generated by wear of the counter gear 1051, the differential gear 1052, etc. Therefore, an oil passage connected to the outlet of the oil sump 1080 is configured so that oil filtered by a strainer flows out. This oil passage is connected to the oil pump 1060. A fourth valve 1003b, which is an on-off valve, is disposed between the oil sump 1080 and the oil pump 1060. The third valve 1003a and the fourth valve 1003b are controlled by the control unit 1090 so that they are always in the same open / closed state. The oil passage connecting the fourth valve 1003b and the oil pump 1060 is connected to the outlet of the stator oil passage 1034a and merges with an oil passage leading to the oil cooler 1070.

[0104] Next, the flow of oil in the oil flow path 1003 will be described. In the following description, it is assumed that the third valve 1003a and the fourth valve 1003b are open. The oil flowing through the oil flow path 1003 is pumped by the oil pump 1060 and flows into the oil cooler 1070. In the oil cooler 1070, heat is exchanged between the oil and the coolant flowing through the coolant flow path 1002, lowering the oil temperature. The oil flowing out of the oil cooler 1070 flows along oil paths that branch off along the way, and the oil flowing through one of the branched oil paths flows into the stator oil path 1034a. The oil flowing through the stator oil path 1034a is heated by heat exchange with the stator 1034 of the traction motor 1031. The oil flowing out of the stator oil path 1034a is returned to the oil pump 1060.

[0105] The oil flowing through the other of the branched oil passages flows through the third valve 1003a, which is in an open state, and then branches off to flow into the shaft oil passage 1032a and the transaxle 1050. The oil flowing through the shaft oil passage 1032a is heated by heat exchange with the shaft 1032 of the travel motor 1031. The oil that flows out of the shaft oil passage 1032a flows into the oil sump 1080. The oil that flows into the transaxle 1050 cools and lubricates the counter gear 1051 and the differential gear 1052 before flowing out and into the oil sump 1080. The oil that flows out of the oil sump 1080 flows through the fourth valve 1003b, which is in an open state, and then returns to the oil pump 1060. When the third valve 1003 a and the fourth valve 1003 b are closed, oil does not flow through the shaft oil passage 1032 a and the transaxle 1050 .

[0106] [Method for Estimating Device Outlet Temperature and Method for Controlling Valve Opening Degrees] In the drive device 1001 of this embodiment, the control unit 1090 estimates the temperature of the coolant (hereinafter referred to as the "device outlet temperature") at the device outlet 1001a (an example of a predetermined location; see FIG. 10 ), where the coolant flows out to the outside of the drive device 1001, based on a virtual opening degree before actually controlling the opening degrees of the first valve 1002a and the second valve 1002b with respect to a predetermined target temperature of the coolant, and controls the opening degrees of the first valve 1002a and the second valve 1002b based on the estimated temperature so as to approach the target temperature. This device outlet temperature is not estimated based on detection values ​​or measurement values ​​of various sensors arranged at the device outlet 1001a, but is estimated based on detection values ​​or measurement values ​​of various sensors arranged at locations other than the device outlet 1001a of the drive device 1001, an estimate based on the detection values ​​or measurement values, or both.

[0107] The device outlet temperature is estimated based on, for example, (1) the temperature of the oil flowing through the oil passage connecting the oil cooler 1070 to the motor unit 1030 and the transaxle 1050, (2) the amount of oil flowing through the oil cooler 1070, (3) the temperature of the coolant flowing through the passage connecting the stator 1034 of the driving motor 1031 to the oil cooler 1070, (4) the amount of coolant flowing through the oil cooler 1070, and (5) the heat exchange performance map of the oil cooler 1070.

[0108] The above (1) can be obtained, for example, from an oil temperature sensor disposed in an oil passage near the inlet of the motor unit 1030. The above (2) can be obtained, for example, from the oil discharge amount measured by a flow meter disposed at the discharge port of the oil pump 1060 or the oil discharge amount estimated from the rotation speed of the oil pump 1060. The above (3) can be obtained, for example, based on (a) the temperature of the stator 1034, (b) the temperature of the coolant at the outlet of the inverter unit 1010, and (c) the amount of coolant circulating through the inverter unit 1010. The above (4) can be obtained from the discharge amount of the coolant discharged from the water pump 1005. The above (5) is stored in advance in a storage unit (not shown) of the control unit 1090.

[0109] (a) in (3) above can be estimated based on, for example, (a-1) the current value flowing through the coil of the driving motor 1031, (a-2) the temperature detected from a temperature sensor such as a thermistor attached to the driving motor 1031, (a-3) the oil temperature detected from an oil temperature sensor placed in the oil passage near the inlet of the motor unit 1030, and (a-4) the oil discharge amount measured from a flow meter placed at the discharge port of the oil pump 1060, or the oil discharge amount inferred from the rotation speed of the oil pump 1060.

[0110] The above (3) (b) can be estimated based on, for example, (b-1) the temperature of the coolant near the inlet of inverter unit 1010 obtained from a temperature sensor disposed in the flow path near the inlet of inverter unit 1010, and (b-2) the amount of coolant circulating through inverter unit 1010 obtained from the discharge amount of coolant discharged from water pump 1005. The above (3) (c) can be obtained from, for example, the discharge amount of coolant measured from a flow meter disposed at the discharge port of water pump 1005, or the discharge amount of coolant estimated from the rotation speed of water pump 1005.

[0111] Next, a method for controlling the apertures of the first valve 1002a and the second valve 1002b of the drive device 1001 by the control unit 1090 will be described. FIG. 11 shows a flowchart of the control unit 1090 controlling the apertures of the first valve 1002a and the second valve 1002b of the drive device 1001. As shown in FIG. 11, the control unit 1090 receives detected values ​​and measured values ​​detected by the various sensors described above (step S1). Next, the control unit 1090 calculates a target temperature of the coolant at the device outlet 1001a (hereinafter referred to as a "target device outlet temperature T0 (an example of a first reference temperature)") based on the status of the vehicle 1004, such as the ambient temperature, the battery temperature, and the driving state (immediately after starting, while driving, or while temporarily stopped) (step S2).

[0112] Next, the control unit 1090 estimates the temperature of the coolant at the device outlet 1001a when the first valve 1002a is assumed to be open (hereinafter referred to as the "first device outlet temperature T1 (an example of information related to heat quantity)") and the temperature of the coolant at the device outlet 1001a when the first valve 1002a is assumed to be closed (hereinafter referred to as the "second device outlet temperature T2 (an example of information related to heat quantity)") (step S3). Next, the control unit 1090 compares the absolute value of the difference between the target device outlet temperature T0 and the first device outlet temperature T1 (hereinafter also referred to as |T0-T1|) with the absolute value of the difference between the target device outlet temperature T0 and the second device outlet temperature T2 (hereinafter also referred to as |T0-T2|) (step S4). If the absolute value of the difference between the target device outlet temperature T0 and the first device outlet temperature T1 is less than or equal to the absolute value of the difference between the target device outlet temperature T0 and the second device outlet temperature T2 (|T0-T1|≦|T0-T2|) (Yes in step S4), the control unit 1090 compares the first device outlet temperature T1 with the upper limit temperature T3 (an example of a second reference temperature) (step S5). If the first device outlet temperature T1 is less than or equal to the upper limit temperature T3 (Yes in step S5), the control unit 1090 controls the first valve 1002a to an open state (step S6). If the first device outlet temperature T1 exceeds the upper limit temperature T3 (No in step S5), the control unit 1090 controls the first valve 1002a to a closed state (step S7).

[0113] The upper limit temperature T3 is, for example, a temperature at which the coolant temperature exceeds the heat dissipation capacity of the radiator or the like of the vehicle 1004 while the vehicle 1004 is running, causing the coolant to flow through the coolant flow path 1002 in a state where the coolant temperature cannot be sufficiently reduced, which may result in overheating the battery or the like. The upper limit temperature T3 is higher than the target device outlet temperature T0.

[0114] Returning to step S4, if the absolute value of the difference between the target device outlet temperature T0 and the first device outlet temperature T1 exceeds the absolute value of the difference between the target device outlet temperature T0 and the second device outlet temperature T2 (|T0-T1|>|T0-T2|) (No in step S4), the control unit 1090 controls the first valve 1002a to be in a closed state (step S7).

[0115] The above control by the control unit 1090 can be summarized as follows: The control unit 1090 controls the opening degree of the first valve 1002a by using either the first device outlet temperature T1 or the second device outlet temperature T2, whichever is closer to the target device outlet temperature T0, within a range in which the first device outlet temperature T1 does not exceed the upper limit temperature T3. However, even if the first device outlet temperature T1 is closer to the target device outlet temperature T0 than the second device outlet temperature T2, if the first device outlet temperature T1 exceeds the upper limit temperature T3, the control unit 1090 controls the first valve 1002a to be in a closed state by using the second device outlet temperature T2.

[0116] Next, estimation of the device outlet temperature and control of the opening degree of the first valve 1002a when the vehicle 1004 is in a different state will be described.

[0117] [Warm-up State Immediately After Vehicle Start] For example, in a cold region where the ambient temperature is -20°C, immediately after starting the vehicle 1004 and before driving, the battery, vehicle body, and traction motor 1031 are cold. Under these conditions, current is applied to the coil using motor current control such that the rotor 1033 of the traction motor 1031 does not rotate. The results of the estimation of the device outlet temperature by the control unit 1090 are shown in FIG. 12. FIG. 12 shows the coolant temperatures in each component of the drive unit 1001 after a predetermined time (e.g., 5 seconds) has elapsed since the first valve 1002a was opened and the second valve 1002b was closed. At this time, the third valve 1003a and the fourth valve 1003b are closed. The components in this example are the inverter 1012, the stator 1034 and case 1035 of the traction motor 1031, the oil sump 1080, and the oil cooler 1070. 12 to 17, the horizontal axis represents the arrangement of the components of the drive unit 1001 in the order in which the coolant flows, and the vertical axis represents the temperature. In Fig. 12 to 17, each component has a width in the horizontal direction, with the left end of the width representing the coolant inlet and the right end representing the coolant outlet.

[0118] In the traction motor 1031, the temperature change due to heat exchange of the coolant flowing through the stator 1034 and the temperature change due to heat exchange of the coolant flowing through the case 1035 are shown side by side for convenience of illustration. In reality, the coolant flowing through the water jacket 1002c of the traction motor 1031 exchanges heat with both the stator 1034 and the case 1035 at the same time.

[0119] As shown in FIG. 12 , in the inverter unit 1010, the temperature of the coolant rises due to heat exchange with the smoothing capacitor 1011, inverter 1012, etc. This is because, although the traction motor 1031 is not rotating, current is still flowing through its coils, and current is also flowing through the smoothing capacitor 1011 and inverter 1012, which are used when switching between the energized coils. In the traction motor 1031, the temperature of the coolant rises due to heat exchange with the stator 1034, but falls due to heat exchange with the case 1035. The temperature rise of the coolant in the stator 1034 occurs because the temperature of the stator 1034 is higher than before current is applied due to current flow through the coils of the traction motor 1031, and the coolant absorbs heat from the stator 1034 as it flows through. The reason for the temperature drop of the coolant in the case 1035 is as follows. The case 1035 is in contact with the transmission (not shown). Since the vehicle 1004 is not moving, the temperature of the transmission is the same as the ambient temperature (-20 degrees in this embodiment). The temperature of the case 1035 itself rises slightly due to the coolant, but because the transmission has a larger heat capacity than the case 1035, the transmission absorbs heat from the coolant through the case 1035, causing the temperature of the coolant to drop. Therefore, when viewed as a whole, the temperature of the coolant at the outlet is lower than the temperature of the coolant at the inlet.

[0120] In this embodiment, because the second valve 1002b is closed, the coolant flowing out of the traction motor 1031 does not flow into the oil sump 1080 and thus does not cool the oil, but instead flows into the oil cooler 1070. The coolant then exchanges heat with the oil flowing through the oil flow path 1003 in the oil cooler 1070, lowering the oil temperature and raising the coolant temperature. The coolant then flows out of the drive unit 1001 from the device outlet 1001a. The temperature of the coolant at the device outlet 1001a at this time is the first device outlet temperature T1. Note that in FIGS. 12 to 17 , the solid lines on the coolant temperature graphs represent estimates made by the control unit 1090, while the dashed lines represent areas not estimated by the control unit 1090 and are simply shown to connect the solid lines.

[0121] 13 shows the temperature of the coolant in each component of the drive unit 1001 when a predetermined time (e.g., 5 seconds) has elapsed since the first valve 1002a was closed and the second valve 1002b was closed, while the third valve 1003a and the fourth valve 1003b were closed.

[0122] As shown in Figure 13, in inverter unit 1010, the temperature of the coolant rises due to heat exchange with smoothing capacitor 1011, inverter 1012, etc., and flows out of inverter unit 1010. At this time, because first valve 1002a is closed, the coolant flowing out of inverter unit 1010 does not flow into motor unit 1030 or transaxle 1050, but flows out of drive unit 1001 from device outlet 1001a. At this time, the temperature of the coolant at device outlet 1001a is second device outlet temperature T2. Also, at this time, the temperature of stator 1034, the temperature of case 1035, the oil temperature of oil sump 1080, and the oil temperature of oil cooler 1070 are all constant from the inlet to the outlet of the coolant because no coolant or oil flows through them.

[0123] 12 and 13, |T0-T1|>|T0-T2| (see No in step S4 in FIG. 11), so the control unit 1090 controls the first valve 1002a to the closed state (see step S7 in FIG. 11).

[0124] [State after vehicle warm-up is complete after start-up] When the vehicle warms up by continuing to energize the traction motor 1031 from the state shown in Figures 12 and 13, the vehicle body is cool, but the temperature of the battery and traction motor 1031 is higher than immediately after warm-up. Under these conditions, current is applied to the coil of the traction motor 1031 using motor current control that prevents the rotor 1033 from rotating, and the controller 1090 estimates the device outlet temperature. Figure 14 shows the results. Figure 14 shows the coolant temperatures in each component of the drive system 1001 after a predetermined time (e.g., 5 seconds) has elapsed since the first valve 1002a was opened and the second valve 1002b was closed. At this time, the third valve 1003a and the fourth valve 1003b are closed.

[0125] 14, in inverter unit 1010, the temperature of the coolant rises due to heat exchange with smoothing capacitor 1011, inverter 1012, etc. Furthermore, in this embodiment, the temperature rise of the coolant due to heat exchange with stator 1034 exceeds the temperature drop of the coolant due to heat exchange with case 1035, and when viewed as a whole, the temperature of the coolant at the outlet rises higher than the temperature of the coolant at the inlet when viewed from the perspective of traction motor 1031. This is because the temperature of stator 1034 is higher than in the state shown in FIG. 12, while the temperature of case 1035 due to heat removed by the transmission is the same as in the state shown in FIG. 12.

[0126] In this embodiment, because the second valve 1002b is closed, the coolant flowing out from the driving motor 1031 does not flow into the oil sump 1080 and does not cool the oil, but instead flows into the oil cooler 1070. Then, in the oil cooler 1070, heat is exchanged with the oil flowing through the oil flow path 1003, causing the temperature of the oil to drop and the temperature of the coolant to rise. The coolant then flows out of the drive unit 1001 from the device outlet 1001a. The temperature of the coolant at the device outlet 1001a at this time is the first device outlet temperature T1.

[0127] 15 shows the temperature of the coolant in each component of the drive unit 1001 when a predetermined time (e.g., 5 seconds) has elapsed since the first valve 1002a was closed and the second valve 1002b was closed, while the third valve 1003a and the fourth valve 1003b were closed.

[0128] 15 , in inverter unit 1010, the temperature of the coolant rises due to heat exchange with smoothing capacitor 1011, inverter 1012, etc., and the coolant flows out of inverter unit 1010. At this time, because first valve 1002a is closed, the coolant flowing out of inverter unit 1010 does not flow into motor unit 1030, but flows out of drive unit 1001 from device outlet 1001a. At this time, the temperature of the coolant at device outlet 1001a is second device outlet temperature T2. Also, at this time, the temperature of stator 1034, the temperature of case 1035, the oil temperature of oil sump 1080, and the oil temperature of oil cooler 1070 are all constant from the inlet to the outlet of the coolant because no coolant or oil flows through them.

[0129] 14 and 15, |T0-T1|<|T0-T2| (see "Yes" in step S4 in FIG. 11), so the control unit 1090 compares the first device outlet temperature T1 with the upper limit temperature T3 (see "Step S5 in FIG. 11"). In FIG. 14, the first device outlet temperature T1 is equal to or lower than the upper limit temperature T3 (see "Yes" in step S5 in FIG. 11), so the control unit 1090 controls the first valve 1002a to an open state (see "Step S6 in FIG. 11").

[0130] [State in which the vehicle is warmed up and running] When the vehicle 1004 is started from the state shown in Figures 14 and 15 and the rotation speed of the traction motor 1031 continues to be high for a long period of time (hereinafter referred to as a continuous high-load state), the vehicle body is cool, but the temperatures of the battery and traction motor 1031 are significantly higher than when the warm-up was complete. Figure 16 shows the results of estimation of the device outlet temperature by the control unit 1090 in this continuous high-load state. Figure 16 shows the coolant temperatures in each component of the drive system 1001 after a predetermined time (e.g., 5 seconds) has elapsed since both the first valve 1002a and the second valve 1002b were assumed to be open. At this time, the third valve 1003a and the fourth valve 1003b are open.

[0131] As shown in FIG. 16 , in the inverter unit 1010, the temperature of the coolant rises due to heat exchange with the smoothing capacitor 1011, inverter 1012, etc. Furthermore, in this embodiment, the degree of temperature rise of the coolant due to heat exchange with the stator 1034 is the same as in FIG. 14 . On the other hand, the degree of temperature drop of the coolant due to heat exchange with the case 1035 is smaller than in FIG. 14 . This is because, as the vehicle 1004 is running, the transmission is also operating, causing the temperature to rise more than in FIG. 14 . Therefore, when viewed as a whole, the temperature of the coolant at the outlet is higher than the temperature of the coolant at the outlet in FIG. 14 .

[0132] In this embodiment, because the second valve 1002b is open, the coolant flowing out from the traction motor 1031 flows toward the oil sump 1080, cooling the oil stored in the oil sump 1080 and increasing its temperature. It then flows into the oil cooler 1070. The coolant exchanges heat with the oil flowing through the oil flow path 1003 in the oil cooler 1070, further increasing the temperature of the coolant. The coolant then flows out of the drive unit 1001 from the device outlet 1001a. The temperature of the coolant at the device outlet 1001a at this time is the first device outlet temperature T1.

[0133] In this embodiment, both the third valve 1003a and the fourth valve 1003b are open, so oil flows through the oil flow path 1003, cooling the traction motor 1031. The oil also flows into the transaxle 1050, cooling and lubricating the counter gear 1051 and the differential gear 1052. The oil that flows through the shaft oil path 1032a and the transaxle 1050 flows into the oil sump 1080. The oil that flows through the stator oil path 1034a flows into the oil pump 1060. Because the traction motor 1031 continues to operate at high speed and the transaxle 1050 is also operating, the temperature of the oil stored in the oil sump 1080 rises. The heated oil is cooled by the coolant flowing through the oil sump 1080 and the oil cooler 1070.

[0134] 17 shows the temperature of the coolant in each component of the drive unit 1001 when a predetermined time (e.g., 5 seconds) has elapsed since the first valve 1002a was closed and the second valve 1002b was closed, while the third valve 1003a and the fourth valve 1003b were closed.

[0135] As shown in FIG. 17 , in the inverter unit 1010, the coolant temperature rises due to heat exchange with the smoothing capacitor 1011, inverter 1012, etc., and flows out of the inverter unit 1010. At this time, because the first valve 1002a is closed, the coolant flowing out of the inverter unit 1010 does not flow into the motor unit 1030 but flows out of the drive unit 1001 through the device outlet 1001a. The temperature of the coolant at the device outlet 1001a at this time is the second device outlet temperature T2. At this time, the temperature of the stator 1034, the temperature of the case 1035, the oil temperature of the oil reservoir 1080, and the oil temperature of the oil cooler 1070 are all constant from the inlet to the outlet of the coolant because no coolant or oil flows through them. However, compared to FIG. 15 , the temperature of the case 1035 and the temperature of the oil stored in the oil reservoir 1080 are elevated.

[0136] 16 and 17, |T0-T1|<|T0-T2| (see Yes in step S4 in FIG. 2), so the control unit 1090 compares the first device outlet temperature T1 with the upper limit temperature T3 (see step S5 in FIG. 11). In FIG. 16, the first device outlet temperature T1 exceeds the upper limit temperature T3 (see No in step S5 in FIG. 11), so the control unit 1090 controls the first valve 1002a to a closed state (see step S7 in FIG. 11).

[0137] In this way, in the drive device 1001 of this embodiment, the control unit 1090 estimates the temperature of the coolant at the device outlet 1001a based on the virtual opening degrees of the first valve 1002a, the second valve 1002b, the third valve 1003a, and the fourth valve 1003b, and controls the opening degrees of the first valve 1002a, the second valve 1002b, the third valve 1003a, and the fourth valve 1003b based on the result.Therefore, compared to controlling the valve opening degrees after an actual malfunction occurs, the coolant temperature can be brought closer to the target device outlet temperature T0 in a short time, and the target state of the vehicle 1004 can be reached in a short time.

[0138] Other Embodiments of the Second Embodiment (1) In the above embodiment, the virtual opening degrees of the first valve 1002a and the second valve 1002b when the control unit 1090 estimates the temperature of the coolant at the device outlet 1001a are set to either fully open or fully closed, but this is not limited to this. The virtual opening degrees of the first valve 1002a and the second valve 1002b set by the control unit 1090 may be other than fully open or fully closed. In this case, the coolant flows through both of the two flow paths.

[0139] (2) In the above embodiment, the parameter estimated by the control unit 1090 is the temperature of the coolant, but this is not limited to this. The parameter may be the balance of heat transferred by the coolant through heat exchange (an example of information related to heat).

[0140] (3) In the above embodiment, the temperature of the coolant at the device outlet 1001a of the drive device 1001 is estimated, but this is not limiting. The temperature of the coolant at another location in the drive device 1001 may be estimated, and the opening degrees of the first valve 1002a and the second valve 1002b may be controlled based on the estimated temperature.

[0141] (4) The configurations disclosed in the above-described embodiments (including the above-described embodiments and other embodiments; the same applies hereinafter) can be applied in combination with configurations disclosed in other embodiments, as long as no contradiction occurs. Regarding other configurations, the embodiments disclosed in this specification are examples in all respects and can be appropriately modified within the scope of the present disclosure.

[0142] [Outline of the embodiment] A drive device according to a first embodiment of the present disclosure preferably includes the following components.

[0143] <1-1> A drive device (1) including a rotating electric machine (2), an inverter device (5) that controls the rotating electric machine (2), and a case (7) that houses the rotating electric machine (2) and the inverter device (5), wherein the inverter device (5) includes a power module (51) including a switching element, a connection terminal (56) that is connected to the rotating electric machine (2), a first bus bar (55) that connects the power module (51) and the connection terminal (56), and a current sensor (57) that detects a current flowing through the first bus bar (55), and a first cooling water passage (8A) through which cooling water flows is provided in the case (7) so as to cool the first bus bar (55), the current sensor (57), and the connection terminal (56).

[0144] A relatively large current often flows through the first bus bar (55) connecting the power module (51) and the connection terminal (56), and the first bus bar (55) is also prone to temperature rise. When the temperature of the first bus bar (55) rises, the heat is transferred to the current sensor (57) and the connection terminal (56), causing these to also rise in temperature. In view of this, according to the above configuration, the first bus bar (55), the current sensor (57), and the connection terminal (56) are cooled by the cooling water flowing through the first cooling water passage (8A), thereby suppressing the temperature rise of these components and making them less likely to reach their heat-resistant temperature. This reduces the likelihood of output limitations being imposed on the inverter device (5), and improves the continuous operation characteristics of the rotating electric machine (2).

[0145] <1-2> In one aspect, the inverter device (5) further includes a capacitor (52) for smoothing the voltage applied to the power module (51), a second cooling water passage (8B) for cooling the rotating electric machine (2) is provided in the case (7), and the first cooling water passage (8A) is preferably formed to further cool the capacitor (52) before communicating with the second cooling water passage (8B).

[0146] According to this configuration, the condenser (52) is further cooled by the cooling water flowing through the first cooling water passage (8A), making it difficult for the condenser (52) and the other components to reach their heat resistance temperature. Furthermore, the cooling water that reaches the second cooling water passage (8B) from the first cooling water passage (8A) also cools the stator (21), thereby suppressing a temperature rise in the rotating electric machine (2) itself. As a result, the continuous operation characteristics of the rotating electric machine (2) can be further improved.

[0147] <1-3> In one aspect, the rotating electric machine (2) includes a stator (21) having a stator core (22) and a stator coil (23) wound around the stator core (22), and a coil cover (25) covering a coil end portion (24) of the stator coil (23) protruding from the stator core (22), wherein a cooling oil passage (9) through which cooling oil flows is formed inside the coil cover (25), and a second bus bar (66) connecting the connection terminal (56) and the stator coil (23) is preferably disposed inside the coil cover (25).

[0148] According to this configuration, the second bus bar (66) can be cooled by the cooling oil flowing through the cooling oil passage (9). Unlike cooling by oil scattered by centrifugal force during operation of the rotating electric machine (2), the coil end portion (24) and the second bus bar (66) can be stably cooled even when the vehicle is stopped or traveling at low speeds. Furthermore, by cooling the second bus bar (66), the connecting terminal (56) and the first bus bar (55) connected thereto can also be cooled. Therefore, the temperature rise of the connecting terminal (56) and the first bus bar (55) can be further suppressed, and the continuous operation characteristics of the rotating electric machine (2) can be further improved.

[0149] <1-4> In one aspect, the inverter device (5) includes a resin cover (60) that integrally covers the current sensor (57), the connection terminal (56), and at least a portion of the first bus bar (55), and it is preferable that at least a portion of the first cooling water channel (8A) is formed inside the resin cover (60).

[0150] According to this configuration, the first cooling water passage (8A) can be formed more easily than, for example, a configuration in which the entire first cooling water passage (8A) is formed in the case (7). Furthermore, the resin cover (60) ensures insulation of the first bus bar (55) and the connection terminal (56) while also allowing them to be appropriately cooled.

[0151] (Other Issues) Japanese Patent Application Laid-Open Publication No. 2020-179839 discloses a vehicle heat pump system for electric vehicles. In this vehicle heat pump system, a single chiller in which a coolant and a refrigerant exchange heat is used to heat or cool a battery module, and waste heat from the motor, electrical components, and battery module is used to heat the vehicle interior. However, for example, when the vehicle is idling, if the waste heat from the motor, electrical components, and battery module is insufficient to heat the vehicle interior, heat is taken in from outside air by controlling the refrigerant and valve opening. Furthermore, even when the waste heat from the motor and electrical components is insufficient to heat the vehicle interior during initial vehicle operation, heat is taken in from outside air by controlling the valve opening.

[0152] However, in the above-mentioned vehicle heat pump system, the ECU detects the temperature inside the vehicle cabin using a sensor or the like and determines that the heating capacity is insufficient, and then controls the valve opening so that heat from the outside air is taken in and used for heating.Therefore, there is a time lag before the vehicle cabin is actually heated sufficiently, and there is room for improvement.

[0153] Therefore, there is a need for a drive device that can advance the timing of the decision to control the valve opening.

[0154] In view of this, the drive device of the second embodiment according to the present disclosure preferably includes the following configurations.

[0155] <2-1> A vehicle drive device (1001) comprising: drive parts (1010, 1030, 1070) for driving a vehicle (1004); a coolant flow path (1002) through which a coolant for cooling the drive parts (1010, 1030, 1070) flows; one or more valves (1002a, 1002b) for controlling the flow rate of the coolant flowing through the coolant flow path (1002) by changing the degree of opening; and a control unit (1090) for controlling the degrees of opening of the valves (1002a, 1002b), wherein the control unit (1090) estimates information relating to the amount of heat obtained by the coolant based on the temperatures of the drive parts (1010, 1030, 1070) and the virtual degrees of opening of the valves (1002a, 1002b), and controls the degrees of opening of the valves (1002a, 1002b) based on the information about the amount of heat.

[0156] According to this embodiment, the control unit (1090) estimates information regarding the amount of heat the coolant will gain based on the temperature of the driving parts (1010, 1030, 1070) and the virtual opening of the valves (1002a, 1002b), and controls the opening of the valves (1002a, 1002b) based on the information regarding the amount of heat. Therefore, compared to controlling the opening of the valves (1002a, 1002b) after an actual malfunction occurs, the coolant can be brought closer to the desired state (e.g., the desired temperature or heat balance) in a short time, and the vehicle (1004) can reach the desired state in a short time.

[0157] <2-2> In one aspect, the information about the amount of heat is preferably the temperature of the coolant at a predetermined location (1001a).

[0158] According to this aspect, if the information regarding the heat quantity is the temperature of the coolant at a specified location (1001a), it is easy to estimate by comparing it with, for example, the heat balance, and the temperature of the coolant can be brought close to the desired temperature in a short period of time.

[0159] <2-3> In one aspect, the control unit (1090) preferably controls the opening of the valves (1002a, 1002b) so that the temperature of the cooling liquid approaches the first reference temperature (T0).

[0160] According to this aspect, the control unit (1090) controls the opening degree of the valves (1002a, 1002b) so that the temperature of the cooling liquid approaches the first reference temperature (T0), thereby enabling the temperature of the cooling liquid to approach the desired temperature in a shorter time.

[0161] <2-4> In one aspect, the control unit (1090) preferably controls the opening of the valves (1002a, 1002b) so that the temperature of the coolant does not exceed a second reference temperature (T3) that is higher than the first reference temperature (T0).

[0162] For example, when the vehicle (1004) is running, if the temperature of the coolant is so high that it exceeds the heat dissipation capacity of the radiator or the like of the vehicle (1004), the coolant may flow through the coolant flow path (1002) without being able to sufficiently lower its temperature, which may result in overheating the battery or the like of the vehicle (1004). Therefore, according to this aspect, the control unit (1090) controls the opening of the valves (1002a, 1002b) so that the temperature of the coolant does not exceed the second reference temperature (T3), which is higher than the first reference temperature (T0), thereby eliminating the risk of overheating the battery or the like of the vehicle (1004).

[0163] It is sufficient for the drive device according to the present disclosure to achieve at least one of the above-described effects.

[0164] 1: drive unit, 2: rotating electric machine, 3: transmission mechanism, 4: output member, 5: inverter device, 7: case, 8: cooling water passage, 8A: first cooling water passage, 8B: second cooling water passage, 8C: third cooling water passage, 9: cooling oil passage, 21: stator, 22: stator core, 23: stator coil, 24: coil end portion, 25: coil cover, 25A: first coil cover, 25B: second coil cover, 27: rotor, 28: rotor shaft, 31: transmission mechanism, 32: output gear, 36: differential gear mechanism, 37: input gear, 45: drive shaft, 51: power module, 52: capacitor, 53 : power supply bus bar, 54: connection bus bar, 55: three-phase bus bar (first bus bar), 56: connection terminal, 57: current sensor, 59: control board, 60: resin cover, 60A: molded portion, 60B: case portion, 61: bus bar covering portion, 62: integrated covering portion, 63: first water channel forming portion, 64: second water channel forming portion, 66: three-phase bus bar (second bus bar), 71: case body, 72: rotating electrical machine housing portion, 73: transmission mechanism housing portion, 74: inverter housing portion, 74A: first base, 74B: second base, 74C: through hole, 76: inner case, 78: first cover, 79: second cover, 81 : First case internal water passage, 82: First base internal water passage, 83: Second case internal water passage, 84: Cover internal water passage, 85: Third case internal water passage, 86: Second base internal water passage, 87: Communication water passage, 88: Stator outer peripheral water passage, 89: Circulation water passage, 91: Cover internal oil passage, 91A: First cover internal oil passage, 91B: Second cover internal oil passage, 92: Core internal oil passage, 93: Circulation oil passage, 110: Water pump, 120: Oil pump, 130: Heat exchanger, 140: Auxiliary equipment, 711: Outer wall portion, 712: Peripheral wall portion, B: Battery, C: Width direction, C1: Width direction first side, C2: Width direction second side, L: Axial direction, L1: Axial direction second side 1 side, L2: second axial side, V: vertical direction, V1: upper side, V2: lower side, VC: vehicle, W: wheel, X1: first axis, X2: second axis 1001a: device outlet (predetermined location), 1002: coolant flow path, 1002a: first valve (valve), 1002b: second valve (valve), 1004: vehicle, 1010: inverter unit (driving component), 1030: motor unit (driving component), 1070: oil cooler (driving component), 1090: control unit, T0: target device outlet temperature (first reference temperature), T1: first device outlet temperature (information regarding heat quantity), T2: second device outlet temperature (information regarding heat quantity),T3: Upper limit temperature (second reference temperature)

Claims

1. A drive device comprising a rotating electric machine, an inverter device that controls the rotating electric machine, and a case that houses the rotating electric machine and the inverter device, wherein the inverter device comprises a power module including a switching element, a connection terminal that is connected to the rotating electric machine, a first bus bar that connects the power module and the connection terminal, and a current sensor that detects the current flowing through the first bus bar, and a first cooling water channel through which cooling water flows is provided within the case so as to cool the first bus bar, the current sensor, and the connection terminal.

2. A drive unit as described in claim 1, wherein the inverter device further comprises a capacitor for smoothing the voltage applied to the power module, a second cooling water passage for cooling the rotating electric machine is provided within the case, and the first cooling water passage is formed to further cool the capacitor before communicating with the second cooling water passage.

3. A drive device as described in claim 1 or 2, wherein the rotating electric machine comprises a stator having a stator core and a stator coil wound around the stator core, and a coil cover covering the coil end portion of the stator coil protruding from the stator core, wherein a cooling oil passage through which cooling oil flows is formed inside the coil cover, and a second bus bar connecting the connection terminal and the stator coil is arranged inside the coil cover.

4. A drive unit according to claim 1 or 2, wherein the inverter device is provided with a resin cover that integrally covers the current sensor, the connection terminal, and at least a portion of the first bus bar, and at least a portion of the first cooling water channel is formed inside the resin cover.

Images