Drive unit

Abstract

A drive unit includes a subframe, a power receiving device, a power storage device, a power control device, and a rotating electrical machine. The sub-frame is fixed to the lower portion of the vehicle body. And the power receiving device is arranged below the auxiliary frame and is fixed with the auxiliary frame into a whole. The power receiving device receives AC power transmitted in a non-contact manner from the power transmitting device. The rotating motor and the auxiliary frame are fixed into a whole. The power storage device and the power control device are integrally fixed to the rotating electric machine. The power storage device and the rotating electric machine transmit and receive power. The power control device controls power transmission and reception between the power storage device and the rotating electric machine.

Description

[0001] This application claims priority based on Japanese Patent Application No. 2023-116538 filed on July 18, 2023 and Japanese Patent Application No. 2024-016482 filed on February 6, 2024, and the contents of which are incorporated herein by reference. Technical Field

[0002] The invention relates to a drive unit. Background Art

[0003] In recent years, more and more people have been conducting research and development related to charging and power supply in vehicles equipped with secondary batteries in order to ensure convenient, reliable, sustainable and advanced energy use, which contributes to energy efficiency.

[0004] Conventionally, in contactless power transmission systems that supply power to a vehicle from outside the vehicle through contactless power transmission, vehicles equipped with an integrated battery, inverter, and power receiving coil are known (for example, refer to Japanese Patent Application Laid-Open No. 2019-92266). Summary of the invention

[0005] However, in the technology related to charging and power supply in a vehicle equipped with a secondary battery, it is desired to suppress the increase in vehicle weight and the mounting volume of the power unit by suppressing the increase in the capacity required for the secondary battery. For example, in the case where the battery cell is assumed to be used as a power source for secondary use as in the above-mentioned conventional vehicle, it is difficult to reduce the capacity of the secondary battery.

[0006] In addition, since the battery needs to be placed under the seat that becomes the passenger space, the living space may be reduced. In addition, the battery is located outside the passenger, so the vehicle body structure is required to cope with collisions such as side collisions, which may increase the weight of the vehicle. In addition, cooling objects with different heat resistance temperatures such as batteries, motors, gears, inverters, and air conditioning devices are installed in various parts of the vehicle, and multiple cooling paths are complicated and expanded, and multiple coolers are also used, which may increase the cost and weight.

[0007] An aspect of the present invention is to provide a drive unit capable of suppressing increases in weight and mounting volume and contributing to energy efficiency.

[0008] The present invention adopts the following scheme.

[0009] (1): A drive unit according to one embodiment of the present invention (e.g., drive unit 1 in the embodiment) comprises: a frame-shaped subframe (e.g., subframe 2 in the embodiment) fixed to the lower part of the vehicle body; a power receiving unit (e.g., power receiving device 4 in the embodiment) fixed to the subframe below the subframe and having a coil (e.g., coil 13 in the embodiment) for receiving AC power transmitted in a non-contact manner from a power transmitting device (e.g., power transmitting device T in the embodiment); a rotating electric machine (e.g., rotating electric machine 7 in the embodiment) fixed to the subframe; and a power storage device (e.g., power storage device 5 in the embodiment) and a power control unit (e.g., power control device 6 in the embodiment) fixed to the rotating electric machine and transmitting and receiving electric power to and from the rotating electric machine.

[0010] (2): In the drive unit described in (1) above, the power storage device and the power control unit may be fixed integrally with the rotating electric machine above the rotating electric machine.

[0011] (3): In the drive unit described in (2) above, the power storage device may be arranged above the rotating electrical machine and the power control unit.

[0012] (4): In the drive unit described in any one of (1) to (3) above, the power receiving portion may include an inner member (for example, inner member 17 in the embodiment) formed of a magnetic material and inserted into a hollow region of the coil (for example, hollow region 13a in the embodiment) and protruding toward the rotating motor, and the inner member may include a frame-shaped wall portion (for example, wall portion 17a in the embodiment) extending in the up-down direction and a cover portion (for example, cover portion 17b in the embodiment) for opening and closing an opening end of the wall portion.

[0013] According to the scheme (1) above, in addition to the remaining capacity (SOC: State Of Charge) of the power storage device, the power received by the power receiving unit from the power transmission unit is used as a virtual SOC, thereby suppressing the increase in the capacity of the power storage device. By suppressing the increase in weight and volume of the power storage device, it is easy to integrate the power storage device, the power control unit, the rotating electric machine and the power receiving unit and fix them to the subframe. By concentrating the cooling objects in one place, a simple cooling structure can be adopted, the number of required heat exchangers can be reduced, and the volume of the motor room can also be reduced, thereby enabling a free vehicle structure to be selected. By integrating, for example, the increase in the length of the required wiring and the resistance loss can be suppressed, and the generation of vibration and vibration sound transmitted from the rotating electric machine to the outside can be suppressed. By suppressing the increase in weight and volume of the power storage device, the vehicle interior space and the luggage room space can be increased. The response to the side collision of the power storage device on the passenger compartment side can be concentrated on the collision response to the motor room, thereby simplifying the vehicle body structure.

[0014] In the case of the above-mentioned solution (2) or (3), the layout of the power storage device, the power control unit and the rotating electric machine can be more diverse and easier to arrange. The cooler can be integrated, thereby making it possible to form a FF (Front Engine Front Drive), shorten the front of the vehicle or reduce the opening, etc., and a free design can be adopted.

[0015] In the case of the above-mentioned solution (4), by opening the cover of the inner member, various devices and components arranged in other spaces communicating with the hollow internal space surrounded by the wall can be easily exposed to the outside, which can improve the ease of various maintenance operations. For example, maintenance operations such as visual inspection of the drive unit mounted on the subframe and replacement of grease can be easily performed through the internal space of the wall of the inner member. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a perspective view showing the structure of a drive unit in the embodiment of the present invention.

[0017] Figure 2 It is an exploded perspective view showing the structure of the coil unit in the embodiment of the present invention.

[0018] Figure 3 The coil unit in the embodiment of the present invention is Figure 2 The cross-sectional view is obtained by cutting through the ZX plane at the position of the III-III line shown.

[0019] Figure 4 It is a cross-sectional view of a coil unit in a first modified example of the embodiment of the present invention.

[0020] Figure 5 It is a cross-sectional view of a coil unit in a second modified example of the embodiment of the present invention. DETAILED DESCRIPTION

[0021] Hereinafter, a driving unit according to an embodiment of the present invention will be described with reference to the drawings.

[0022] Figure 1 It is a perspective view showing the structure of the drive unit 1 in the embodiment. Figure 2 It is an exploded perspective view showing the structure of coil unit 10 in the embodiment. Figure 3 The coil unit 10 in the embodiment is Figure 2 The cross-sectional view is obtained by cutting through the ZX plane at the position of the III-III line shown.

[0023] Hereinafter, the directions of the X-axis, Y-axis, and Z-axis that are orthogonal to each other in a three-dimensional space are directions parallel to the axes. Figure 1 to Figure 3 As shown, the Z-axis direction is parallel to the up-down direction of a moving body such as a vehicle equipped with the drive unit 1, the X-axis direction is parallel to the front-rear direction of the moving body, and the Y-axis direction is parallel to the left-right direction of the moving body. For example, the positive direction of the Z-axis is the upward direction of the moving body, the positive direction of the X-axis is the front direction of the moving body, and the positive direction of the Y-axis is the right direction of the moving body.

[0024] The drive unit 1 of the embodiment is mounted on, for example, a vehicle that receives power from the outside by contactless power transmission. The vehicle is, for example, an electric vehicle such as an electric automobile, a hybrid vehicle, or a fuel cell vehicle.

[0025] like Figure 1 As shown, the drive unit 1 includes an integrally constructed subframe 2, a drive control device 3, and a power receiving device 4. For example, the drive control device 3 is fixed to the upper part of the subframe 2 and the power receiving device 4 is fixed to the lower part of the subframe 2, which is a frame-shaped subframe 2 provided at the lower part of the vehicle body.

[0026] The subframe 2 is, for example, a front subframe fixed to the lower part of the vehicle body to carry a drive unit and a front suspension. The outer shape of the subframe 2 is, for example, formed in a frame shape. The subframe 2 is, for example, formed by an iron material (i.e., a material with iron as the main component) having a smaller R component of complex magnetic permeability than SS (Steel Structure) and SC (Steel Carbon) or SPCC (Steel Plate Cold Commercial). The subframe 2 is, for example, formed by a steel material with relatively small iron loss (a material in which a plurality of materials are mixed in order to reduce iron loss). When composed of SS or SC, in order to suppress the increase of internal loss, more magnetic bodies such as ferrite are arranged to avoid magnetic flux passing through the subframe 2.

[0027] The drive control device 3 includes, for example, a power storage device 5 , a power control device 6 , and a rotating electric machine 7 .

[0028] The power storage device 5 is, for example, arranged above the power control device 6 and the rotating electric machine 7. The power storage device 5 includes, for example, a high-voltage battery as a power source of the vehicle. The power storage device 5 includes, for example, a box-shaped battery case and a plurality of battery modules arranged in the battery case. The battery module includes a plurality of battery cells connected in series or in parallel. The power storage device 5 is charged by power transmitted in a contactless manner from a power transmission device T outside the vehicle. The power storage device 5 exchanges power with the rotating electric machine 7 through the power control device 6.

[0029] The power control device 6 is, for example, arranged between the power storage device 5 and the rotating electric machine 7. The power control device 6 includes, for example, a box-shaped housing and a power conversion module arranged in the housing. The power conversion module includes, for example, a bridge circuit formed by a plurality of switching elements and a rectifier element connected in a three-phase bridge. Each switching element is, for example, a transistor such as an IGBT (Insulated Gate Bipolar Transistor) or a MOSFET (Metal Oxide Semi-conductor Field Effect Transistor) of SiC (Silicon Carbide). The rectifier element is, for example, a return diode connected in parallel with each transistor. The power control device 6 controls the power transfer between the power storage device 5 and the rotating electric machine 7 by, for example, bidirectional power conversion between DC power and AC power.

[0030] The rotating electric machine 7 is, for example, arranged above the sub-frame 2 and fixed to the sub-frame 2 as a whole. The rotating electric machine 7 is, for example, arranged below the power storage device 5 and the power control device 6 and fixed to the power storage device 5 and the power control device 6 as a whole. The rotating electric machine 7 has, for example, a cylindrical housing and a motor arranged in the housing. The motor is, for example, a three-phase AC brushless DC motor set for driving the vehicle. The motor performs a power operation by the power supplied from the power control device 6, thereby generating a rotational driving force. The motor can also perform a regenerative operation by the rotational power input from the wheel side of the vehicle, thereby generating generated power. When the motor can be connected to the internal combustion engine of the vehicle, it can also generate power by the power of the internal combustion engine.

[0031] The power receiving device 4 is disposed, for example, below the subframe 2 and fixed integrally to the subframe 2. The power receiving device 4 includes a coil unit 10. The coil unit 10 constitutes a part of the power receiving device 4, which receives AC power from an external power transmitting device T by contactless power transmission.

[0032] like Figure 2 and Figure 3 As shown, the coil unit 10 includes, for example, a frame 11 , a first cover 12 , a coil 13 , an insulating member 14 , a core member 15 , a back member 16 , an inner member 17 , and a second cover 18 .

[0033] The outer shape of the frame 11 is formed into a rectangular frame shape, for example. The frame 11 is formed of a material such as a resin having a predetermined thermal conductivity. The frame 11 includes a first housing portion 21 and a second housing portion 22, for example. The coil 13, the insulating member 14, and the core member 15 described later are arranged in the first housing portion 21. The substrates 23, 26, 27, the capacitor 24, and the semiconductor element 28 described later are arranged in the second housing portion 22. The first housing portion 21 is provided, for example, in a manner of surrounding the lower side in the up-down direction and the inner side and the outer side in the direction perpendicular to the up-down direction with respect to the coil 13, the insulating member 14, and the core member 15 described later. The second housing portion 22 is provided, for example, at a position further back than the first housing portion 21 in the front-back direction. The second housing portion 22 is provided, for example, in a manner of surrounding the upper side in the up-down direction and the outer side in the direction perpendicular to the up-down direction with respect to the substrates 23, 26, 27, the capacitor 24, and the semiconductor element 28 described later.

[0034] The frame 11 includes, for example, a first surface 11A having a plurality of grooves 11a formed in the first housing portion 21. The first surface 11A of the frame 11 (i.e., the surface on the lower side in the up-down direction, i.e., the lower surface) is exposed to the outside below the vehicle body. The plurality of grooves 11a are formed in a manner along the flow direction of wind (travel wind) received by the vehicle when it is traveling, for example, along the front-rear direction.

[0035] The frame 11 includes, for example, a plurality of heat dissipation members 11 b protruding inward from a first inner surface 11B on the back side relative to the first surface 11A. The heat dissipation members 11 b have, for example, a plate-like fin shape. The plurality of heat dissipation members 11 b are in contact with the coil 13 .

[0036] The outer shape of the first cover 12 is, for example, a rectangular plate having a through hole 12a formed in the thickness direction. The first cover 12 is, for example, provided in a manner to surround the upper side in the up-down direction relative to the coil 13, the insulating member 14, and the core member 15 described later. The first cover 12 forms a housing space for housing the coil 13, the insulating member 14, and the core member 15 between the first cover 12 and the first inner surface 11B of the frame 11. The first cover 12 closes the open end of the first housing portion 21 of the frame 11 that houses the coil 13, the insulating member 14, and the core member 15. It should be noted that the first cover 12 may be formed, for example, so as to ensure thermal conductivity by casting with a thermally conductive resin.

[0037] The outer shape of the coil 13 is formed in, for example, a rectangular spiral shape along the first inner surface 11B of the frame body 11. The coil 13 is disposed, for example, on the upper side of the first inner surface 11B. The wire of the coil 13 is in direct contact with the plurality of heat dissipation members 11b.

[0038] The insulating member 14 has a rectangular sheet shape with a through hole 14 a formed in the thickness direction. The insulating member 14 is made of a material having electrical insulation. The insulating member 14 is disposed, for example, above the coil 13 .

[0039] The outer shape of the core member 15 is, for example, a rectangular plate having a through hole 15a formed in the thickness direction. The core member 15 is, for example, made of a non-directional (isotropic) magnetic material such as ferrite, or a directional (anisotropic) magnetic material such as an electromagnetic steel plate such as a silicon steel plate, or a soft magnetic material such as a nanocrystalline soft magnetic material, which has a large magnetic permeability and a small iron loss in a predetermined frequency band (such as the 85 kH band). The core member 15 is, for example, arranged on the upper side of the insulating member 14.

[0040] The outer shape of the back member 16 is, for example, a rectangular plate having a through hole formed in the thickness direction. The outer shape of the inner member 17 is, for example, a box-shaped having a wall portion 17a penetrating in the vertical direction in a rectangular frame shape and a cover portion 17b closing the lower open end of the wall portion 17a. The inner member 17 protrudes downward in the vertical direction from the peripheral portion surrounding the through hole of the back member 16. The back member 16 and the inner member 17 are, for example, integrally formed of a magnetic material with a large magnetic permeability such as a nanocrystalline soft magnetic sheet or an electromagnetic steel sheet such as a ferrite or silicon steel sheet processed to prevent scattering by epoxy resin.

[0041] The back member 16 is disposed, for example, on the upper side in the up-down direction relative to the first cover 12. The inner member 17 is inserted, for example, into the first cover 12, the through holes 12a, 15a, 14a of the core member 15 and the insulating member 14, the hollow region 13a of the coil 13, and the through hole 11c in the thickness direction of the frame 11. The inner member 17 protrudes downward from the first surface 11A of the frame 11, for example.

[0042] The outer shape of the second cover 18 is formed in a rectangular plate shape, for example. The second cover 18 is provided, for example, to surround the lower side in the vertical direction with respect to each substrate 23, 26, 27, capacitor 24, and semiconductor element 28 described later. The second cover 18 forms a housing space for housing each substrate 23, 26, 27, capacitor 24, and semiconductor element 28 between the second cover 18 and the second inner surface 11C of the second housing portion 22 of the frame body 11. The second cover 18 closes the open end of the second housing portion 22 of the frame body 11 that houses each substrate 23, 26, 27, capacitor 24, and semiconductor element 28.

[0043] The capacitor substrate 23 fixes a plurality of capacitors 24 such as film capacitors. The capacitors 24 are, for example, resonance capacitors connected to the coil 13. The plurality of capacitors 24 are fixed to the capacitor substrate 23 and contact the inner surface of the second cover 18 via a heat conducting member 25 such as thermal paste.

[0044] The control substrate 26 is, for example, arranged above the capacitor substrate 23. The control substrate 26 controls, for example, power conversion of the power receiving device and communication with the external power transmitting device T. The control substrate 26 is a software function unit that performs functions by executing a predetermined program using a processor such as a CPU (Central Processing Unit). The software function unit is an ECU (Electronic Control Unit) having a processor such as a CPU, a ROM (Read Only Memory) for storing programs, a RAM (Random Access Memory) for temporarily storing data, and electronic circuits such as a timer. It should be noted that at least a part of the control substrate 26 may also be an integrated circuit such as an LSI (Large Scale Integration).

[0045] The control substrate 26 generates a control signal to be input to the gate drive substrate 27, for example, based on the target output of the power receiving device. The control signal is, for example, a signal indicating the timing of turning on (conducting) / off (isolating) a plurality of switching elements constituting the power conversion unit of the power receiving device. For example, the control signal is a pulse width modulated signal.

[0046] The gate drive substrate 27 is disposed, for example, above the control substrate 26. The gate drive substrate 27 is connected to gates of a plurality of switching elements constituting a power conversion unit of the power receiving device, for example. The gate drive substrate 27 includes, for example, an integrated circuit and a plurality of gate resistors.

[0047] The gate drive substrate 27 generates a gate signal for driving each switching element to actually turn on (conduct) or turn off (block) based on the control signal received from the control substrate 26. For example, the gate drive substrate 27 performs amplification and level shifting of the control signal to generate the gate signal.

[0048] The semiconductor element 28 is, for example, a switching element and a rectifying element constituting the power conversion unit of the power receiving device 4. The switching element is, for example, a transistor such as a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) of SiC (Silicon Carbide). The rectifying element is, for example, a return diode connected in parallel with each transistor. The plurality of semiconductor elements 28 are, for example, fixed to the upper portion of the gate drive substrate 27 and arranged between the gate drive substrate 27 and the second inner surface 11C of the frame 11.

[0049] The housing 11 includes a heat sink 29 disposed on an outer surface (second surface) 11D opposite to the second inner surface 11C. The heat sink 29 includes, for example, a water jacket formed of a water cooling structure and a heat sink having a plurality of fin members protruding to the outside.

[0050] The housing 11 includes, for example, a DC connector 30 that is connected to the power conversion unit of the power receiving device 4 and that protrudes to the outside (upward) from the second surface 11D.

[0051] As described above, according to the drive unit 1 of the embodiment, in addition to the remaining capacity (SOC: State Of Charge) of the power storage device 5, the power received by the power receiving device 4 from the power transmission device T is used as a virtual SOC, thereby suppressing the increase in the capacity of the power storage device 5. By suppressing the increase in the weight and volume of the power storage device 5, it is easy to integrate the power storage device 5, the power control device 6, the rotating electric machine 7 and the power receiving device 4 and fix them to the subframe 2. By integrating, for example, it is possible to suppress the increase in the length and resistance loss of the required wiring, and it is possible to suppress the generation of vibration and vibration sound transmitted from the rotating electric machine 7 to the outside. By suppressing the increase in the weight and volume of the power storage device 5, it is possible to increase the vehicle interior space and the luggage room space. The diversity and ease of layout of the power storage device 5, the power control device 6 and the rotating electric machine 7 can be improved.

[0052] (Variation Example)

[0053] It should be noted that in the above embodiment, the subframe 2 is the front subframe, but it is not limited thereto and may be, for example, the rear subframe. That is, the drive control device 3 and the power receiving device 4 may be fixed integrally with the rear subframe.

[0054] In addition, in the above-mentioned embodiment, the cover part 17b of the inner member 17 may be provided so that it can be opened and closed or removed with respect to the wall part 17a.

[0055] Figure 4 It is a cross-sectional view of coil unit 10A in a first modified example of the embodiment.

[0056] like Figure 4 As shown, in the coil unit 10A of the first modification, the cover 17b of the inner member 17 slides relative to the wall 17a by, for example, a sliding mechanism, thereby opening and closing the lower opening end of the wall 17a.

[0057] Figure 5 2 is a cross-sectional view of coil unit 10B according to a second modification of the embodiment.

[0058] like Figure 5 As shown, in the coil unit 10B of the second modification, the cover 17b of the inner member 17 is rotated relative to the wall 17a by a so-called hatch structure, for example, to open and close the lower opening end of the wall 17a.

[0059] According to the first or second modification described above, by opening the cover portion 17b of the inner member 17, various devices and components arranged in other spaces communicating with the hollow internal space surrounded by the wall portion 17a can be easily exposed to the outside, and the ease of various maintenance operations can be improved. For example, maintenance operations such as visual inspection of the drive control device 3 such as the drive unit mounted on the subframe 2 and replacement of grease can be easily performed through the internal space of the wall portion 17a of the inner member 17.

[0060] It should be noted that, for example, a bottom cover having a structure that is fastened and connected by a one touch clip or a half lock bolt and can be removed in the vertical direction may be used as the cover portion 17b. According to these modified examples, the magnetic structure is a three-dimensional structure and can be opened and closed, so that, for example, grease, bolt fastening connection, and oil leakage can be checked during vehicle inspection, or an inspection hole can be ensured when grease is replaced by a dealer or the like.

[0061] The embodiments of the present invention are provided as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and changes can be made without departing from the scope of the main purpose of the invention. These embodiments and their variations are included in the scope and main purpose of the invention, and are also included in the invention described in the technical solution and its equivalent scope.

Claims

1. A drive unit, wherein: The drive unit comprises: A frame-shaped subframe fixed to the lower part of the vehicle body; a power receiving unit fixed integrally with the sub-frame below the sub-frame and having a coil for receiving AC power transmitted from the power transmitting device in a non-contact manner; A rotating motor fixed integrally with the sub-frame; as well as The power storage device and the power control unit are fixed integrally to the rotating electric machine, and the power storage device exchanges electric power with the rotating electric machine.

2. The drive unit according to claim 1, wherein: The power storage device and the power control unit are fixed integrally with the rotating electric machine above the rotating electric machine.

3. The drive unit according to claim 2, wherein: The power storage device is arranged above the rotating electric machine and the power control unit.

4. The drive unit according to any one of claims 1 to 3, wherein: The power receiving unit includes an inner member formed of a magnetic material and inserted into a hollow region of the coil and protruding toward the rotating electrical machine. The inner member includes a frame-shaped wall portion penetrating in the up-down direction and a cover portion that opens and closes an opening end of the wall portion.

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