Drive unit

Abstract

To provide a drive unit capable of suppressing an increase in a weight and a capacity.SOLUTION: A drive unit 1 includes a sub-frame 2, a power-receiving device 4, a power storage device 5, a power control unit 6 and a rotary electric machine 7. The sub-frame 2 is fixed to the lower part of a vehicle body. The power-receiving device 4 is integrally fixed to the sub-frame 2 below the sub-frame 2. The power-receiving device 4 receives AC power transmitted from a power transmission device T in a non-contact manner. The rotary electric machine 7 is integrally fixed to the sub-frame 2. The power storage device 5 and the power control unit 6 are integrally fixed to the rotary electric machine 7. The power storage device 5 transmits and receives power with the rotary electric machine 7. The power control unit 6 controls power transmission and reception between the power storage device 5 and the rotary electric machine 7.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a drive unit. [Background technology]

[0002] In recent years, research and development has been conducted into charging vehicles equipped with secondary batteries that contribute to energy efficiency, in order to ensure that more people have access to affordable, reliable, sustainable and advanced energy. 2. Description of the Related Art Conventionally, in a contactless power transfer system that supplies power from outside the vehicle to the vehicle by contactless power transfer, a vehicle equipped with an integrated battery, inverter, and power receiving coil is known (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-92266 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology for charging and supplying power to a vehicle equipped with a secondary battery, it is desirable to suppress an increase in the vehicle weight and the mounting volume of the power unit by suppressing an increase in the capacity required for the secondary battery. For example, when it is assumed that the battery alone is used as a power source, as in the vehicle of the above-mentioned conventional technology, a problem occurs in that it is difficult to reduce the capacity of the secondary battery. In addition, batteries must be installed under the seats, which is the passenger space, which may result in a decrease in living space. Also, since the batteries are located outside the passengers, a body structure is required to respond to side impacts and other collisions, which may lead to an increase in vehicle weight. Also, cooling objects with different heat resistance temperatures, such as the battery, motor, gears, inverter, and air conditioner, are installed in various places in the vehicle, which may result in multiple cooling paths and multiple coolers, which may increase costs and weight.

[0005] An object of the present invention is to provide a drive unit capable of suppressing increases in weight and mounting volume, which in turn contributes to improved energy efficiency. [Means for solving the problem]

[0006] In order to solve the above problems and achieve the above object, the present invention employs the following aspects. (1): A drive unit according to one aspect of the present invention (e.g., drive unit 1 in the embodiments) includes a frame-shaped subframe (e.g., subframe 2 in the embodiments) fixed to the bottom of a vehicle body, a power receiving unit (e.g., power receiving device 4 in the embodiments) fixed integrally with the subframe below the subframe and having a coil (e.g., coil 13 in the embodiments) that receives AC power transmitted contactlessly from a power transmitting device (e.g., power transmitting device T in the embodiments), a rotating electric machine (e.g., rotating electric machine 7 in the embodiments) fixed integrally with the subframe, and a power storage device (e.g., power storage device 5 in the embodiments) and a power control unit (e.g., power control device 6 in the embodiments) fixed integrally with the rotating electric machine and transmitting and receiving power to and from the rotating electric machine.

[0007] (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.

[0008] (3) In the drive unit described in (2) above, the power storage device may be disposed above the rotating electric machine and the power control unit.

[0009] (4): In the drive unit described in any one of (1) to (3) above, the power receiving portion includes an inner member (e.g., inner member 17 in the embodiment) made of a magnetic material that is inserted into an air-core region (e.g., air-core region 13a in the embodiment) of the coil and protrudes toward the rotating electric machine, and the inner member may include a frame-shaped wall portion (e.g., wall portion 17a in the embodiment) that penetrates in the vertical direction, and a lid portion (e.g., lid portion 17b in the embodiment) that opens and closes the opening end of the wall portion. Effect of the Invention

[0010] According to the above (1), 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 transmitting device is set as a virtual SOC, so that an increase in the capacity of the power storage device can be suppressed. By suppressing an increase in the weight and volume of the power storage device, it becomes 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 consolidating the objects to be cooled in one place, it becomes possible to adopt a simple cooling structure, and the number of required heat exchangers can be reduced, which in turn reduces the volume of the motor room, allowing for a free selection of vehicle structure. By integrating, for example, it is possible to suppress an increase in the length of the required wiring and electrical resistance loss, and it is also possible to suppress the generation of vibrations and vibration noise transmitted from the rotating electric machine to the outside. By suppressing an increase in the weight and volume of the power storage device, it is possible to increase the vehicle interior space and the luggage compartment space. By consolidating the measures against a side impact, etc. against the power storage device on the passenger compartment side into the measures against a collision against the motor room, it is possible to simplify the body structure.

[0011] In the case of (2) or (3) above, it is possible to improve the diversity and simplicity of the layout of the power storage device, the power control unit, and the rotating electrical machine. By being able to integrate the cooler, it is possible to adopt a free design, such as shortening the nose and reducing the number of openings, even though it is a front engine front drive (FF) vehicle, because the cooler can be integrated.

[0012] In the case of (4) above, by opening the lid of the inner member, various devices and components arranged in other spaces that communicate with the hollow internal space surrounded by the wall can be easily exposed to the outside, improving the ease of various maintenance work. For example, maintenance work such as visual inspection of the drive unit mounted on the subframe and replacement of oils and greases can be easily performed through the internal space of the wall of the inner member. [Brief description of the drawings]

[0013] [Figure 1] FIG. 2 is a perspective view showing a configuration of a drive unit according to the embodiment of the present invention. [Diagram 2] FIG. 2 is an exploded perspective view showing a configuration of a coil unit according to an embodiment of the present invention. [Diagram 3] 3 is a cross-sectional view of the coil unit according to the embodiment of the present invention, taken along the ZX plane at the position of line AA shown in FIG. 2. [Figure 4] FIG. 4 is a cross-sectional view of a coil unit according to a first modified example of the embodiment of the present invention. [Diagram 5] FIG. 11 is a cross-sectional view of a coil unit according to a second modified example of the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A drive unit according to an embodiment of the present invention will now be described with reference to the accompanying drawings. Fig. 1 is a perspective view showing the configuration of a drive unit 1 in an embodiment. Fig. 2 is an exploded perspective view showing the configuration of a coil unit 10 in an embodiment. Fig. 2 is a cross-sectional view of the coil unit 10 in the embodiment cut by a ZX plane at the position of line AA shown in Fig. 2. In the following, the directions of the X-axis, Y-axis, and Z-axis, which are mutually orthogonal in a three-dimensional space, are parallel to each other. For example, as shown in Figures 1 to 3, the Z-axis direction is parallel to the up-down direction of a moving body such as a vehicle on which the drive unit 1 is mounted, 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 forward direction of the moving body, and the positive direction of the Y-axis is the rightward direction of the moving body.

[0015] A drive unit 1 of the embodiment is mounted on, for example, a vehicle that receives electric power from the outside through contactless power transmission. The vehicle is, for example, an electrically powered vehicle such as an electric vehicle, a hybrid vehicle, or a fuel cell vehicle. 1, 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 an upper part of the subframe 2, and the power receiving device 4 is fixed to a lower part of the subframe 2, which is a frame-shaped frame provided on the lower part of the vehicle body.

[0016] The subframe 2 is, for example, a front subframe that is fixed to the lower part of the vehicle body and mounts a drive unit, a front suspension, and the like. The outer shape of the subframe 2 is, for example, formed in a frame shape. The subframe 2 is formed of, for example, SS (Steel Structure) and SC (Steel Carbon) or SPCC (Steel Plate Cold Commercial) or other iron material (i.e., material mainly composed of iron) having a smaller R component of complex permeability compared to SS (Steel Structure) and SC (Steel Carbon). The subframe 2 is formed, for example, of a steel material with relatively small iron loss (such as a material in which multiple materials are mixed to reduce iron loss). When the subframe 2 is made of SS or SC, a large amount of magnetic material such as ferrite is arranged to suppress an increase in internal loss, so that magnetic flux does not penetrate the subframe 2.

[0017] The drive control device 3 includes, for example, an electricity storage device 5, a power control device 6, and a rotating electric machine 7. The power storage device 5 is disposed, for example, above the power control device 6 and the rotating electric machine 7. The power storage device 5 includes, for example, a high-voltage battery that is a power source for the vehicle. The power storage device 5 includes, for example, a box-shaped battery case and a plurality of battery modules disposed in the battery case. The battery module includes a plurality of battery cells connected in series or parallel. The power storage device 5 is charged by power transmitted contactlessly from a power transmission device T outside the vehicle. The power storage device 5 exchanges power with the rotating electric machine 7 via the power control device 6.

[0018] The power control device 6 is disposed, for example, between the power storage device 5 and the rotating electric machine 7. The power control device 6 includes, for example, a box-shaped case and a power conversion module disposed in the case. The power conversion module includes, for example, a bridge circuit formed by a plurality of switching elements and rectifying elements that are bridge-connected in three phases or the like. Each switching element is, for example, a transistor such as an IGBT (Insulated Gate Bipolar Transistor) or a SiC (Silicon Carbide) MOSFET (Metal Oxide Semiconductor Field Effect Transistor). The rectifying element is, for example, a free wheel diode connected in parallel to each transistor. The power control device 6 controls the exchange of power between the power storage device 5 and the rotating electric machine 7 by, for example, bidirectional power conversion between DC power and AC power.

[0019] The rotating electric machine 7 is disposed, for example, above the subframe 2 and fixed integrally therewith. The rotating electric machine 7 is disposed, for example, below the power storage device 5 and the power control device 6 and fixed integrally therewith. The rotating electric machine 7 includes, for example, a cylindrical housing and a motor disposed in the housing. The motor is, for example, a three-phase AC brushless DC motor or the like provided for driving the vehicle. The motor generates a rotational driving force by performing a power running operation using power supplied from the power control device 6. The motor may generate power by performing a regenerative operation using rotational power input from the wheel side of the vehicle. If the motor can be connected to an internal combustion engine of the vehicle, the motor may generate power using the power of the internal combustion engine.

[0020] The power receiving device 4 is disposed, for example, below the subframe 2 and fixed integrally with 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 that receives AC power from an external power transmitting device T by contactless power transmission. As shown in FIGS. 2 and 3, the coil unit 10 includes, for example, a housing 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.

[0021] The outer shape of the housing 11 is formed, for example, in a rectangular frame shape. The housing 11 is formed, for example, from a material such as resin having a predetermined thermal conductivity. The housing 11 includes, for example, a first housing section 21 and a second housing section 22. The first housing section 21 includes a coil 13, an insulating member 14, and a core member 15, which will be described later. The second housing section 22 includes boards 23, 26, and 27, a capacitor 24, and a semiconductor element 28, which will be described later. The first housing section 21 is provided, for example, so as to surround the lower side in the vertical direction and the inner and outer sides in a direction perpendicular to the vertical direction with respect to the coil 13, the insulating member 14, and the core member 15, which will be described later. The second housing section 22 is provided, for example, behind the first housing section 21 in the front-rear direction. The second housing section 22 is provided, for example, so as to surround the upper side in the vertical direction and the outer side in a direction perpendicular to the vertical direction with respect to the boards 23, 26, and 27, the capacitor 24, and the semiconductor element 28, which will be described later.

[0022] The housing 11 has, for example, a first surface 11A in which a plurality of grooves 11a are formed in the first housing portion 21. The first surface 11A (i.e., the lower surface, which is the surface on the lower side in the up-down direction) of the housing 11 is exposed to the outside below the vehicle body. The plurality of grooves 11a are formed, for example, along the front-rear direction so as to be aligned with the flow direction of wind (traveling wind) received while the vehicle is traveling. The housing 11 includes, for example, a plurality of heat dissipation members 11b protruding inward from a first inner surface 11B on the rear side of the first surface 11A. The heat dissipation members 11b have, for example, a plate-like fin-shaped outer shape. The plurality of heat dissipation members 11b contact the coil 13.

[0023] The outer shape of the first cover 12 is formed, for example, in a rectangular plate shape with a through hole 12a formed in the thickness direction. The first cover 12 is provided, for example, so as to surround the upper side in the vertical direction of the coil 13, the insulating member 14, and the core member 15 described later. The first cover 12 forms an accommodation space between the first cover 12 and a first inner surface 11B of the housing 11 in which the coil 13, the insulating member 14, and the core member 15 are accommodated. The first cover 12 closes the open end of the first accommodation section 21 of the housing 11 in which the coil 13, the insulating member 14, and the core member 15 are accommodated. The first cover 12 may be formed, for example, by being cast with a thermally conductive resin to ensure thermal conductivity.

[0024] The outer shape of coil 13 is formed, for example, in a rectangular spiral shape along first inner surface 11B of housing 11. Coil 13 is disposed, for example, above first inner surface 11B. The wire of coil 13 is in direct contact with multiple heat dissipation members 11b. The insulating member 14 has an outer shape of, for example, a rectangular sheet with through holes 14a formed in the thickness direction. The insulating member 14 is made of an electrically insulating material. The insulating member 14 is disposed above the coil 13, for example. The outer shape of the core member 15 is formed, for example, in a rectangular plate shape with through holes 15a formed in the thickness direction. The core member 15 is formed of a magnetic material with high magnetic permeability and low iron loss in a predetermined band (such as 85 kH band), such as 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. The core member 15 is disposed, for example, above the insulating member 14.

[0025] The outer shape of the back member 16 is, for example, a rectangular plate with a through hole formed in the thickness direction. The outer shape of the inner member 17 is, for example, a rectangular frame-like box shape with a wall portion 17a penetrating in the vertical direction and a lid 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 integrally formed from a magnetic material with high magnetic permeability, such as a nanocrystalline soft magnetic sheet, ferrite treated with epoxy resin to prevent scattering, or an electromagnetic steel plate such as a silicon steel plate.

[0026] The back member 16 is disposed, for example, on the upper side in the up-down direction with respect to the first cover 12. The inner member 17 is inserted, for example, into the through holes 12a, 15a, 14a of the first cover 12, the core member 15, and the insulating member 14, the hollow-core region 13a of the coil 13, and the through hole 11c in the thickness direction of the housing 11. The inner member 17 protrudes downward from the first surface 11A of the housing 11, for example.

[0027] The outer shape of the second cover 18 is formed, for example, in a rectangular plate shape. The second cover 18 is provided, for example, so as to surround the lower side in the up-down direction of each of the boards 23, 26, 27, the capacitor 24, and the semiconductor element 28 described below. The second cover 18 forms an accommodation space between the second cover 18 and the second inner surface 11C of the second accommodation section 22 of the housing 11 in which the boards 23, 26, 27, the capacitor 24, and the semiconductor element 28 are accommodated. The second cover 18 closes the open end of the second accommodation section 22 of the housing 11 in which the boards 23, 26, 27, the capacitor 24, and the semiconductor element 28 are accommodated.

[0028] The capacitor board 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 board 23 and are in contact with the inner surface of the second cover 18 via a thermally conductive material 25, such as a thermal compound.

[0029] The control board 26 is disposed, for example, above the capacitor board 23. The control board 26 controls, for example, power conversion of the power receiving device and communication with an external power transmitting device T. The control board 26 is a software function unit that functions when a processor such as a CPU (Central Processing Unit) executes a predetermined program. The software function unit is an ECU (Electronic Control Unit) that includes a processor such as a CPU, a ROM (Read Only Memory) that stores programs, a RAM (Random Access Memory) that temporarily stores data, and electronic circuits such as a timer. At least a part of the control board 26 may be an integrated circuit such as an LSI (Large Scale Integration). The control board 26 generates a control signal to be input to the gate drive board 27 in accordance with, for example, a target output of the power receiving device. The control signal is, for example, a signal indicating the timing to turn on (conductive) / off (cutoff) a plurality of switching elements constituting a power conversion unit of the power receiving device. For example, the control signal is a pulse-width modulated signal.

[0030] The gate drive board 27 is disposed, for example, above the control board 26. The gate drive board 27 is connected to the gates of a plurality of switching elements constituting a power conversion unit of the power receiving device, and includes, for example, an integrated circuit and a plurality of gate resistors. The gate drive board 27 generates gate signals for actually driving each switching element to turn on (conductive) / off (cut-off) based on the control signals received from the control board 26. For example, the gate drive board 27 performs amplification and level shifting of the control signals to generate the gate signals.

[0031] The semiconductor elements 28 are, for example, switching elements and rectifying elements that constitute a power conversion unit of the power receiving device 4. The switching elements are, for example, transistors such as SiC (Silicon Carbide) MOSFETs (Metal Oxide Semiconductor Field Effect Transistors). The rectifying elements are, for example, free wheel diodes connected in parallel to each transistor. The multiple semiconductor elements 28 are, for example, fixed to the upper part of the gate drive substrate 27 and disposed between the gate drive substrate 27 and the second inner surface 11C of the housing 11.

[0032] 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 having a water-cooled structure and a heat sink having a plurality of fin members protruding to the outside. The housing 11 includes, for example, a DC connector 30 that is connected to a power conversion unit of the power receiving device 4 and protrudes outward (upward) from the second surface 11D.

[0033] 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 transmitting device T is set as a virtual SOC, so that an increase in the capacity of the power storage device 5 can be suppressed. By suppressing an increase in the weight and volume of the power storage device 5, it becomes 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 them, for example, it is possible to suppress an increase in the length of the required wiring and an increase in electrical resistance loss, and it is possible to suppress the generation of vibration and vibration noise transmitted from the rotating electric machine 7 to the outside. By suppressing an increase in the weight and volume of the power storage device 5, it is possible to increase the vehicle interior space and the luggage compartment space. It is possible to improve the diversity and easiness of the layout of the power storage device 5, the power control device 6, and the rotating electric machine 7.

[0034] (Modification) In the above embodiment, the subframe 2 is a front subframe, but is not limited thereto and may be, for example, a rear subframe. In other words, the drive control device 3 and the power receiving device 4 may be fixed integrally with the rear subframe.

[0035] In the above-described embodiment, the lid portion 17b of the inner member 17 may be provided so as to be openable / closable or detachable with respect to the wall portion 17a. FIG. 4 is a cross-sectional view of a coil unit 10A in a first modified example of the embodiment. As shown in FIG. 4, in the coil unit 10A of the first modified example, the cover portion 17b of the inner member 17 opens and closes the lower open end of the wall portion 17a by sliding relative to the wall portion 17a using, for example, a slide mechanism. FIG. 5 is a cross-sectional view of a coil unit 10B in a second modified example of the embodiment. As shown in FIG. 5, in the coil unit 10B of the second modified example, the cover portion 17b of the inner member 17 rotates relative to the wall portion 17a by, for example, a so-called hatch structure or the like, thereby opening and closing the lower open end of the wall portion 17a. According to the first or second modified example described above, by opening the lid 17b of the inner member 17, various devices and components arranged in other spaces that communicate with the hollow internal space surrounded by the wall 17a can be easily exposed to the outside, improving the ease of various maintenance operations. 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 oils and greases can be easily performed through the internal space of the wall 17a of the inner member 17. In addition, for example, an undercover that is fastened by a one-touch clip or a half-lock bolt and has a structure that allows it to be removed in the vertical direction may be provided as the lid portion 17b. According to these modified examples, the magnetic structure has a three-dimensional structure and can be opened and closed, so that, for example, it is possible to check the fastening of oil bolts and oil leakage during finished vehicle inspection, and it is also possible to secure a maintenance hole when changing oils and greases at a dealer, etc.

[0036] The embodiments of the present invention are presented 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 modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope of the invention and its equivalents as described in the claims, as well as the scope and spirit of the invention. [Explanation of symbols]

[0037] Reference Signs List 1...drive unit, 2...subframe, 3...drive control device, 4...power receiving device (power receiving section), 5...power storage device, 6...power control device (power control section), 7...rotating electric machine, 10, 10A, 10B...coil unit, 11...housing, 11a...groove, 11b...heat dissipation member, 11c...through hole, 12...first cover, 12a...through hole, 13...coil, 13a...air-core region, 14...insulating member, 14a...through hole, 15...core member, 15a...through hole, 16...back member, 17...inner member, 18...second cover, 23...capacitor board, 24...capacitor, 25...thermal conductive material, 26...control board, 27...gate drive board, 28...semiconductor element, 29...heat sink, 30...DC connector, T...power transmission device.

Claims

1. A frame-shaped subframe fixed to the lower part of the vehicle body; a power receiving unit that is fixed integrally with the subframe below the subframe and has a coil that receives AC power transmitted from a power transmitting device in a non-contact manner; a rotating electric machine fixed integrally to the subframe; a power storage device and a power control unit that are fixed integrally with the rotating electric machine and that exchange electric power with the rotating electric machine; Equipped Drive unit.

2. The power storage device and the power control unit are fixed integrally with the rotating electric machine above the rotating electric machine.

2. A drive unit according to claim 1.

3. The power storage device is disposed above the rotating electric machine and the power control unit. A drive unit according to claim 2.

4. The power receiving unit is an inner member made of a magnetic material that is inserted into an air-core region of the coil and protrudes toward the rotating electric machine; The inner member is The container has a frame-shaped wall portion that penetrates in the vertical direction and a lid portion that opens and closes the open end of the wall portion. A drive unit according to any one of claims 1 to 3.

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