JP2011195097A - Vehicle driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle driving device capable of individually driving wheels with a structure easily deployable to a conventional automobile without increasing the unsprung load of a suspension device.SOLUTION: The vehicle driving device includes a wheel suspension 1 with a spring 18, an inverter integrated type rotating electric machine 7 having an inverter 5 along a rotary shaft of a rotor 7r and adjacent a stator 7s, and a power transmission mechanism 2 which converts the rotational direction of the inverter integrated type rotating electric machine 7 to the rotational direction of a wheel 9, and transmits the driving force by the inverter integrated type rotating electric machine 7 to the wheel 9. The inverter integrated type rotating electric machine 7 has a rotary shaft of the rotor 7r coaxial to the center axis of the vibration suppressing direction of the wheel suspension 1, and a lower end on the side of the wheel 9 is installed on the side of a vehicle body 8 from the lower end on the side of the wheel 9 of a spring 18.

Description

  The present invention relates to a vehicle drive device that drives wheels by a rotating electrical machine.

  Automobiles have progressed by pursuing the three requirements of "running", "turning", and "stopping", and devising and improving the mechanism. As automobiles become more popular, we have made progress by pursuing five requirements that add “comfort” and “safety”. Of course, improvements have been made from the viewpoint of low pollution and energy conservation, but in recent years, attempts have been made to reduce the environmental impact caused by the consumption of fossil fuels, and the environmental impact compared to automobiles driven by internal combustion engines. A small car has been proposed. An electric vehicle driven by a motor (rotary electric machine) and a hybrid vehicle driven by an internal combustion engine and a motor are examples. Some electric vehicles and hybrid vehicles have motors that individually drive the wheels. As an example of such a motor, an in-wheel motor installed inside a wheel is known.

  Naturally, it is not preferable to reduce the above-mentioned five requirements even in these automobiles that place importance on the environment. The automobile is equipped with a suspension in order to reduce vibrations, improve stability during running, steering, and stopping, and ensure the safety of passengers while improving the comfort of riding. The suspension is configured using components such as a spring, a damper (shock absorber), and a suspension arm. When the wheel is a steering wheel, a stabilizer or the like is further used. The strut suspension is widely used because it has a simple structure, has a small number of parts, is light in weight, and can absorb vibrations from the road surface in a large range, but the vehicle's height is likely to increase in size. It also has a surface. For example, in a structure in which shock absorbers are stacked on the upper part of the in-wheel motor, the size of the vehicle in the height direction is likely to increase, and it is difficult to adopt it for a small vehicle.

  Therefore, Japanese Patent Laying-Open No. 2006-240430 (Patent Document 1) proposes a vehicle drive device that is downsized while mounting an in-wheel motor. Specifically, on the side of the housing of the in-wheel motor (520), the shock absorber (560) is disposed so as to partially overlap in the height direction. Thereby, the height of the vehicle drive device can be suppressed. The U, V, and W phase power cables (536, 538, and 540) that supply drive current to the in-wheel motor (520) are fixed to the case of the in-wheel motor 520 using a wiring clamp (522). (The reference numerals in parentheses are those of Patent Document 1).

JP-A-2006-240430 (9th to 25th paragraphs, FIGS. 1, 4 and the like)

  In the vehicle drive device of Patent Document 1, a suspension using a spring (563) and a shock absorber (560) is employed. However, because of the structure of the in-wheel motor, the weight of the wheel increases, so that the unsprung load increases and the resonance frequency of the spring decreases. As a result, passenger comfort may be impaired, and vibration resistance of the in-wheel motor may be reduced. On the other hand, specializing the suspension will lead to an increase in vehicle prices. Moreover, since an in-wheel motor mounts a motor naturally, it is necessary to also dedicate the structure of a wheel.

  In view of the above background, it is desired to provide a vehicle drive device that can individually drive wheels with a structure that can be easily deployed in a conventional automobile without increasing the unsprung load of the suspension device.

In view of the above problems, the characteristic configuration of the vehicle drive device according to the present invention is as follows.
A wheel suspension with a spring that is installed between the wheel and the vehicle body and softens vibrations in a predetermined vibration suppression direction;
An inverter-integrated dynamoelectric machine in which an inverter that converts electric power between DC power and three-phase AC power is provided adjacent to a stator along a rotation axis of a rotor, the center of the wheel suspension in the vibration suppression direction The inverter-integrated dynamoelectric machine having the rotating shaft of the rotor coaxially with the shaft, the lower end on the wheel side being installed on the vehicle body side than the lower end on the wheel side of the spring;
A power transmission mechanism that converts a rotation direction of the inverter-integrated rotating electrical machine into a rotation direction of the wheel and transmits a driving force of the inverter-integrated rotating electrical machine to the wheel.

  According to this feature, a rotating electrical machine having a large weight is generally not disposed under a spring, so that a so-called “unsprung load” does not increase unlike an in-wheel motor. Therefore, the vibration suppression function by the suspension device works well, and passenger comfort is not impaired. In addition, there is little influence on the brakes provided on the wheels. For this reason, the vehicle drive device can be easily deployed in a conventional automobile. Further, since the rotating electrical machine is an inverter-integrated rotating electrical machine in which an inverter is integrated, it is not necessary to secure a wiring space between the inverter and the rotating electrical machine, and a reduction in size is realized. Furthermore, since the inverter-integrated rotating electrical machine is integrated with an inverter, it can be easily deployed to various types of vehicles, can easily achieve mass production effects, and can be applied well to small cars and popular cars. In addition, the inverter-integrated rotating electric machine is installed at a higher position than the in-wheel motor in which the rotating electric machine is incorporated inside the wheel, so that water can enter the rotating electric machine and the inverter even if there is a large puddle or heavy rain. Hateful. Even if it has a waterproof structure, the reliability decreases when water is present in the surroundings, but it can be highly reliable because it is difficult for water to continuously exist around the inverter-integrated rotating electrical machine. .

  In addition, it is preferable that the three-phase legs of the inverter of the vehicle drive device according to the present invention are arranged in a region divided in the circumferential direction of the stator. Since the three-phase legs of the inverter are divided into regions in the circumferential direction of the stator, the inverter can be configured thinly along the rotation axis direction of the rotor, and the inverter-integrated rotating electrical machine can be made compact. Can be configured. In addition, since the stator coils for each phase of the stator are divided into regions in the circumferential direction of the stator, the stator coils for each phase and each leg are arranged close to each other at a substantially equal distance. . Therefore, the wiring space between the inverter and the stator coil can be saved, and the generation of power loss and radiation noise can be suppressed.

  The inverter-integrated rotating electrical machine of the vehicle drive device according to the present invention is preferably disposed inside the spring of the wheel suspension. When the inverter-integrated rotating electrical machine is disposed inside the spring, the rotating electrical machine can be accommodated in the wheel suspension. Therefore, the vehicle drive device can be realized in a state in which the general shape of the general wheel suspension is substantially maintained.

  Further, it is preferable that the inverter of the vehicle drive device according to the present invention is provided on the vehicle body side of the inverter-integrated rotating electrical machine. Since the control device for controlling the inverter is often provided on the vehicle body side, the wiring distance between the inverter and the control device can be shortened.

  Moreover, it is preferable that the inverter-integrated dynamoelectric machine of the vehicle drive device according to the present invention further includes a heat sink adjacent to the inverter along the rotation axis of the rotor. The inverter can be effectively cooled by the heat sink. Here, the heat sink is preferably connected to the vehicle body. The inverter can be cooled more effectively by using a vehicle body having a large heat mass.

  Moreover, it is preferable that the inverter of the vehicle drive device according to the present invention is configured to have an empty space that goes around a central axis that is coaxial with the rotation axis of the rotor. Even when the inverter is arranged on the wheel side of the rotating electrical machine, the rotor rotation shaft and the power transmission mechanism shaft can be passed through the empty space. In addition, a rotation sensor or the like that detects the rotation of the rotor can be effectively installed in the empty space.

A longitudinal sectional view schematically showing the structure of a vehicle drive device Longitudinal sectional view schematically showing the state where the spring is extended III-III sectional view of FIG. 1 schematically showing the structure of the rotating electrical machine Circuit block diagram schematically showing the circuit configuration of the inverter Top view schematically showing a configuration example of an inverter using an IGBT module Schematic perspective view of IGBT module Top view schematically showing a configuration example of an IGBT module Outline drawing schematically showing an example of the appearance of an IGBT chip Outline drawing schematically showing an example of the appearance of a diode chip The figure which shows the example of the power transmission mechanism typically Sectional drawing which shows the example of a deceleration mechanism typically Sectional drawing which shows the example of the interruption | blocking mechanism of a power transmission mechanism typically Sectional drawing which shows another structure of an inverter typically Circuit block diagram schematically showing circuit configuration of 3-level inverter Circuit block diagram schematically showing another circuit configuration of a three-level inverter

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present embodiment, as a main drive device, for example, a vehicle drive device that provides an auxiliary drive force in a vehicle including an internal combustion engine will be described as an example. In general, an electric vehicle has technical and cost problems for increasing the capacity of a battery that is directly connected to a cruising distance, as well as problems related to a battery charging location and a charging time. For this reason, hybrid vehicles using an internal combustion engine are becoming popular. On the other hand, since a hybrid vehicle uses both an internal combustion engine and a motor, the structure of the drive device is generally complicated, and there is a limit to keeping the vehicle price low. For this reason, it is difficult to deploy to inexpensive small cars. For the purpose of reducing the environmental load, it is preferable to put many environment-friendly vehicles on the market. For example, a method of using a motor (rotary electric machine) only in a speed (rotation speed) region where the energy efficiency of the internal combustion engine is low and limiting the role of providing assist torque as an auxiliary driving force is one solution. . In such an application, the motor (rotary electric machine) has a specification that is much lower in output than the hybrid vehicle, and the motor can also be a small one that drives one wheel.

  As shown in FIG. 1, the vehicle drive device includes a wheel suspension 1, an inverter-integrated rotating electrical machine 7, and a power transmission mechanism 2. The wheel suspension 1 is installed between the vehicle body 8 and the wheel 9 and softens vibrations in a predetermined vibration direction in the vertical direction in the figure. In the present embodiment, a strut suspension including a spring (coil spring / helical spring) 18 between the upper spring receiver 17 and the lower spring receiver 19 is illustrated. The wheel suspension 1 is provided with an inverter-integrated rotating electricity 7 (hereinafter simply referred to as “rotating electric machine” as appropriate) having a rotating shaft of a rotor 7r coaxially with a central axis in a vibration suppressing direction.

  The rotary electric machine 7 is an inverter-integrated rotary electric machine in which an inverter 5 that converts electric power between DC power and three-phase AC power is provided adjacent to the stator 7s along the rotation axis of the rotor 7r. In the rotating electrical machine 7, at least the lower end on the wheel 9 side of the rotating electrical machine 7 is installed closer to the vehicle body 8 than the lower end on the wheel 9 side of the spring 18. In this embodiment, as shown in FIGS. 1 and 2, the rotating electrical machine 7 is installed on the upper spring receiver 17.

  As described above, since the rod 80 of the power transmission mechanism 2 is installed at a position where the strut shaft is disposed in a general strut suspension, the ring-shaped cylinder 11 and the piston 12 are disposed so as to surround the rod 80. An absorber 10 is provided. The absorber 10 is a rod 80 and a coaxial absorber. As shown in FIG. 2, the thrust from the road surface, that is, the unsprung state, is absorbed by the expansion and contraction of the spring 18 and the buffering force of the absorber 10. At this time, the rotating electrical machine 7 having a large weight is generally not provided under the spring, so that the unsprung load hardly increases due to the addition of the rotating electrical machine 7 to the wheel suspension 1. Therefore, even if the rotating electrical machine 7 is provided, the suspension function is satisfactorily exhibited and passenger comfort is ensured.

  A rod 80 of the power transmission mechanism 2 is provided at a position where a strut shaft is arranged in a general strut suspension. The rod 80 is connected to the rotation shaft of the rotor 7r. The rod 80 constitutes a part of the power transmission mechanism 2 that converts the rotating direction of the rotating electrical machine 7 to the rotating direction of the wheel 9 and transmits the driving force of the rotating electrical machine 7 to the wheel 9. The tip of the rod 80 is provided with a pinion gear 22 that is one side of a bevel gear mechanism. The pinion gear 22 engages with the spur gear 21 that is the other side of the bevel gear mechanism. The spur gear 21 is provided coaxially with the wheel 9. The bevel gear mechanism having the pinion gear 22 and the spur gear 21 also constitutes a part of the power transmission mechanism 2.

  Further, since the rotational speed of the rotating electrical machine 7 is generally much higher than the rotational speed of the wheels 9, the vehicle drive device is provided with the speed reduction mechanism 4. Here, an example is shown in which the speed reduction mechanism 4 is configured using a two-stage planetary gear mechanism for the output of the rotor 7r. If the rotating electrical machine 7 and the wheel 9 are always connected by the power transmission mechanism 2 including the speed reduction mechanism 4, the rotating electrical machine 7 needs to be rotated at a high speed when the vehicle travels at a high speed. In the rotating electrical machine, the counter electromotive force increases as the rotational speed increases. For this reason, in order to make the rotating electrical machine correspond to the high-speed rotation range, field weakening control that weakens the field and reduces the counter electromotive force generated by the rotation of the rotor 7r, or boosting that makes the voltage of the DC power source higher than the counter electromotive force. Control is required. On the other hand, when the rotating electrical machine 7 that applies the auxiliary driving force is stopped, the rotor 7r is rotated by the rotational force of the wheels 8, so that the load on the internal combustion engine that is the main driving device increases, and the fuel efficiency is increased. May be exacerbated.

  The vehicle drive device of the present embodiment is an auxiliary drive device, and is small in size so that the rotating electrical machine 7 is provided together with the strut type wheel suspension 1. For example, it is sufficient to have a performance capable of applying assist torque in a region where the efficiency of the internal combustion engine is not good, such as when starting, when driving at a low speed after starting, or when climbing at a low speed. Therefore, when the vehicle shifts to high speed travel, the power transmission by the power transmission mechanism 2 can be canceled. As shown in FIGS. 1 and 2, in this embodiment, the speed reduction mechanism 4 constituting the power transmission mechanism 2 is provided with an electromagnetic clutch 25. When the electromagnetic clutch 25 is engaged, the driving force of the rotating electrical machine 7 is transmitted to the wheel 9, and when the electromagnetic clutch 25 is released, the rotating electrical machine 7 becomes free with respect to the wheel 9. In addition, when the wheel 9 provided with the rotating electrical machine 7 is a steering wheel in a four-wheel vehicle, the reaction of the driving torque of the rotating electrical machine 7 also becomes the steering torque, which may cause disturbance when the vehicle turns. Therefore, for example, when the steering is operated, the operation (powering and regeneration) of the rotating electrical machine 7 may be limited.

  Moreover, since the rotary electric machine 7 of this embodiment is an inverter integrated type, it is small as shown in FIG.1 and FIG.2, and space efficiency is good even if it adds to the wheel suspension 1. FIG. Hereinafter, the configuration of the inverter-integrated dynamoelectric machine 7 will be specifically described. As shown in FIGS. 3 and 4, in the present embodiment, a rotating electrical machine 7 having a stator 7 s having six poles corresponding to a four-pole (two-pole pair) rotor 7 r will be described as an example. Since the stator 7s has six salient poles, the stator coil 7c (7u, 7v, 7w) excited in three phases in the U phase, the V phase, and the W phase is provided with two lines as shown in FIG. . When the rotating electrical machine 7 functions as an electric motor, DC power between the positive electrode PV and the negative electrode NV supplied from a DC power source such as a battery (not shown) is converted into AC by the inverter 5. When the rotating electrical machine 7 functions as a generator, the generated AC power is converted to DC by the inverter 5 and regenerated to a DC power source such as a battery (not shown).

  As shown in FIG. 4, the inverter 5 is configured using a switching element. The switching element is a power semiconductor element such as a power transistor, a power MOSFET (metal oxide semiconductor field effect transistor), an IGBT (insulated gate bipolar transistor), or an IPS / IPD (intelligent power switch / device). In this embodiment, the case where IGBT is used as a switching element is illustrated. The capacitor 59 is a smoothing capacitor provided between both positive and negative electrodes. Note that it is preferable that the capacitor 59 is also integrated with the rotating electrical machine 7 by making the capacitor 50 a circular film capacitor.

  The inverter 5 includes a U-phase leg 5U, a V-phase leg 5V, and a W-phase leg 5W corresponding to the three phases of the rotating electrical machine 7. Each leg 5U, 5V, 5W is comprised by the upper stage arm 5P and the lower stage arm 5N which are respectively connected in series. In each leg, the IGBT constituting the upper arm 5P and the IGBT constituting the lower arm 5N are connected in series. The collector of the IGBT of the upper arm 5P of each leg 5U, 5V, 5W is connected to a high voltage power supply line connected to the positive electrode PV, and the emitter of the IGBT of the lower arm 5N of each leg 5U, 5V, 5W is connected to the negative electrode NV. Connected to the connecting low voltage power line. Further, flywheel diodes are connected in parallel to the IGBTs of the respective arms. The inverter 5 is connected to a control unit (not shown) via a driver circuit (not shown). Each IGBT performs a switching operation in accordance with a control signal generated by the control unit. The control unit is configured as an ECU (electronic control unit) having a logic circuit such as a microcomputer as a core and having an interface circuit and other peripheral circuits, and is mounted on the vehicle body side.

  In this embodiment, the inverter 5 is configured in a ring shape as shown in FIG. 5 and is installed adjacent to the stator 7 s as shown in FIGS. 1 and 2 to constitute the inverter-integrated rotating electrical machine 7. As shown in FIG. 6, each arm 5P, 5N is constituted by an IGBT module (power semiconductor module) 3 that is modularized with an IGBT 5Q and a flywheel diode 5D. Six arms, that is, six IGBT modules 3 are combined in a ring shape as shown in FIG. In the present embodiment, the ring-shaped inverter 5 is configured by arranging the trapezoidal power semiconductor modules 3 in a regular hexagonal shape.

  In this embodiment, as shown in FIG. 7, the IGBT 5Q is configured by arranging six regular triangular IGBT chips 3Q in a regular hexagonal shape and connecting them to each other. As shown in FIG. 8, the IGBT chip 3Q is a semiconductor chip having a regular triangular surface shape. FIG. 8A is a top view showing the appearance of one surface of the chip, and FIG. 8B is a bottom view showing the appearance of the other surface of the chip. As shown in FIG. 8A, on one surface, an emitter terminal E is provided at the apex of an equilateral triangle, and a gate terminal G is provided at the opposite side facing the apex. Further, as shown in FIG. 8B, the collector terminal C is provided on the other side of the entire surface.

  As shown in FIG. 9, the flywheel diode 5D is also configured by a diode chip 3D, which is a semiconductor chip having a regular triangular surface shape. FIG. 9A is a top view showing the appearance of one surface of the diode chip 3D, and FIG. 9B is a bottom view showing the appearance of the other surface of the diode chip 3D. As shown in FIG. 9A, the anode terminal A is provided on one side of the surface over almost the entire surface of the equilateral triangle. Further, as shown in FIG. 9B, the cathode terminal K is provided on the other side of the entire surface.

  As shown in FIGS. 6 and 7, the IGBT module 3 includes a collector terminal C on the lower surface side of the IGBT chip 3Q and a cathode terminal K on the lower surface side of the diode chip 3D on a trapezoidal (isosceles trapezoidal) copper plate 31. Are soldered using a high melting point solder. If the long side of the parallel opposite sides of the trapezoidal copper plate 31 is the lower base, the diode chips 3D are mounted on the two apex sides of the lower base. Since the copper plate 31 is connected to the collector terminal C of the IGBT chip 3Q, the cathode terminal K of the diode chip 3D is connected via the copper plate 31 to constitute one arm 5P, 5N. The copper plate 31 is preferably a nickel-plated copper plate 31 or a solderable copper plate 31. As described above, since the collector terminal C and the cathode terminal K are provided over almost the entire surface on the lower surface side of the chip, the contact resistance is small and a large current is conducted well. Further, by bringing the IGBT chip 3Q and the diode chip 3D through which a large current flows into contact with the copper plate 31 having good thermal conductivity over a wide area, the thermal resistance associated with the mounting of the IGBT chip 3Q and the diode chip 3D on the copper plate is lowered, and heat dissipation is achieved. Can be improved.

  As shown in FIG. 8, the emitter terminal E of the IGBT chip 3Q is arranged at the apex of a regular triangular chip. As shown in FIG. 7, in the IGBT module 3, the IGBT chip 3 </ b> Q is mounted on the copper plate 31 with the apex portion where the emitter terminal E is disposed facing each other. In this example, the IGBT 5Q is formed in a regular hexagonal shape by the six IGBT chips 3Q. The emitter terminal E gathers at the center of the regular hexagon and is made a common terminal by evaporating electrodes D conducting to all six IGBT chips 3Q as shown in FIG. Of course, the emitter terminals E may be connected by wire bonding or by soldering. As shown in FIG. 7, the gate terminal G is disposed on the outer periphery of a regular hexagon. The gate terminals G of the adjacent IGBT chips 3Q are connected to each other by wire bonding B or vapor deposition of an electrode (not shown) to become a common gate terminal of the IGBT 5Q.

  As shown in FIG. 5, in the present embodiment, the ring-shaped inverter 5 is configured by arranging the trapezoidal power semiconductor modules 3 in a regular hexagonal shape. As shown in the circuit block diagram of FIG. 4, the copper plate 31 that is electrically connected to the collector terminal C of the IGBT 5Q that constitutes the upper arm 5P is connected to the positive electrode PV of the DC power supply. The emitter terminal E of the IGBT 5Q constituting the lower arm 5N is connected to the negative electrode NV of the DC power supply. Since the positive electrode PV and the negative electrode NV of the DC power supply are common to the three legs, respectively, as shown in FIG. 5, the outer peripheral side is connected to the common plate 34 connected to the positive electrode PV, and the inner peripheral side is connected to the negative electrode NV. A common plate 35 is provided. Of course, a common plate connected to the positive electrode PV may be provided on the inner peripheral side, and a common plate connected to the negative electrode NV may be provided on the outer peripheral side.

  On the other hand, the coil end of the stator coil 7 c of the stator 7 s is connected to the inverter 5 via the bus bar 71. As shown in FIG. 6, the IGBT module 3 is provided with a terminal 32 that can be connected to the bus bar 71, and each stator coil 7 c (7 u, 7 v, 7 w) and the inverter 5 are connected. The bus bar 71 is electrically connected between the connection point between the emitter of the IGBT 5Q of the upper arm 5P of each phase leg 5U, 5V, 5W and the collector of the IGBT 5Q of the lower arm 5N and the stator coil 7c of each phase of the rotating electrical machine 7. Connect to. An inverter drive signal from a control unit (not shown) is connected to the gate terminal G of the IGBT module 3.

  Since the copper plate 31 and the collector terminal of the IGBT 5Q are connected to each other, the copper plate 31 of at least the three IGBT modules 3 constituting the lower arm 5N has a terminal 32 rising vertically from the plate surface of the copper plate 31 as shown in FIG. Is provided. As shown in FIG. 5, the bus bar 71 and the terminal 31 of the IGBT module 3 can be connected in a state where the main body of the rotating electrical machine 7 and the inverter 5 are arranged. As shown in FIG. 6, the terminal 31 and the bus bar 71 of the IGBT module 3 are provided with through holes 33 and 73 that can be fastened by bolts (not shown). Of course, you may connect by other methods, such as welding both.

  The inverter 5 installed adjacent to the stator 7s of the rotating electrical machine main body is directly connected to the bus bar 71 extending from the stator 7s in this way. The stator coils 7c (7u, 7v, 7w) and the inverter 5 can be connected very easily without providing any special electrical connection means such as a harness or connector for connecting the inverters 5.

  In the above description, the terminal 32 is provided on the copper plate 31 of at least three IGBT modules 3. However, as shown in FIG. 5, the terminals 32 may be provided on the copper plates 31 of all the IGBT modules 3. By making all the parts common, the manufacturing cost can be reduced. Further, the terminal 32 can be used to connect the collector of the upper arm 5P to the outer common plate 34 (positive electrode PV). FIG. 5 also shows the housing 7h of the rotating electrical machine 7, but it is preferable that the housing 7h is provided with a space through which the bus bar 71 and the terminal 32 of the IGBT module 3 fastened to the bus bar 71 pass. It is.

  The IGBT module 3 is mounted on the substrate 51 as shown in FIGS. A heat sink 6 is installed between the substrate 51 and the housing 7 h of the rotating electrical machine 7. The housing 7h is always exposed to the outside air in the tire house of the vehicle. In particular, the air around the housing 7h is always replaced while the vehicle is traveling. Therefore, the IGBT module 3 is satisfactorily cooled via the heat sink 6 and the housing 7h.

  As described above with reference to FIGS. 5 to 9, by forming the ring-shaped inverter 5 using the trapezoidal IGBT module 3, a hexagonal empty space is formed at the center of the ring. As is apparent from FIGS. 1 and 2, the rotation shaft of the rotor 7 r and the rod 80 of the power transmission mechanism 2 can be disposed in this space. Furthermore, since the rotation axis of the rotor 7r and its extension line can be arranged, as shown in FIG. 5, it is also possible to arrange the rotation detection sensor 90 in the center of the ring-shaped inverter 5.

  As described above, the power transmission mechanism 2 that converts the rotation direction of the rod 80 into the rotation direction of the wheel 9 is configured using a bevel gear mechanism. At this time, the rotational axes of the spur gear 21 that rotates coaxially with the wheel 9 and the pinion gear 22 that rotates coaxially with the rod 80 may intersect at one point, or may be different by providing an offset. That is, as shown in FIG. 10 (a), straight teeth (quickly) gears may be used to align the axes of the spur gear 21A and the pinion gear 22A, and as shown in FIG. 10 (b), the curved teeth (Surrounding) The spur gear 21B and the pinion gear 22B may have different axes using gears.

  As described above, since the rotational speed of the rotating electrical machine 7 is generally much higher than the rotational speed of the wheel 9, the speed reduction mechanism 4 is provided. 1 and 2 show an example in which the speed reduction mechanism 4 is configured using a two-stage planetary gear mechanism. However, the present invention is not limited to this, and the speed reduction mechanism 4 may be configured using a one-stage planetary gear mechanism as shown in FIG. Further, the speed reduction mechanism 4 may be configured by the gear ratio of the bevel gear of the power transmission mechanism 2 without being limited to the planetary gear mechanism. For example, as shown in FIG. 11B, the speed reduction mechanism 4 can be realized by increasing the number of teeth of the spur gear 21C with respect to the pinion gear 22C.

  Further, as described above, in the present embodiment, the speed reduction mechanism 4 is provided with the electromagnetic clutch 25 as a cutoff mechanism so that the power transmission by the power transmission mechanism 2 can be released. The shut-off mechanism is not limited to the electromagnetic clutch 25, and a synchromesh mechanism as shown in FIG. When the vehicle decelerates from high speed traveling, the rotating electrical machine 7 can function as a generator by re-engaging the power transmission mechanism 2. At this time, regenerative braking can also be realized by the resistance force of the rotor 7r. When re-engaging when the vehicle travels at a relatively high speed, it is important to synchronize the rotation. In this case, it is preferable to use a cyclomesh mechanism rather than the electromagnetic clutch 25 as a shut-off mechanism (re-engagement mechanism).

  Fig.12 (a) has shown the interruption | blocking state of the power transmission mechanism 2 using a cyclomesh mechanism, and FIG.12 (b) has shown the engagement state. When engaged from the shut-off state in FIG. 12 (a), rotation is synchronized by bringing the synchronizer ring 27 into contact with the cone surface 28 and smoothly synchronizing with the wedge effect. When the rotation is synchronized, the comb teeth 29 are engaged and the synchronizer ring 27 is fixed as shown in FIG. When opening the ring gear, no sync mechanism is required, so power transmission is released by a light pulling force. Control of the synchronizer ring 27 is preferably performed using a solenoid or a wire actuator.

  In the above, based on FIG.1 and FIG.2, the example which the IGBT module 3 was cooled favorably through the heat sink 6 and the housing 7h was shown. However, as shown in FIG. 13, the IGBT module 3 (copper plate 31, IGBT chip 3 </ b> Q), the substrate 51, and the heat sink 6 are stacked opposite to those in FIGS. 1 and 2, and the inverter 5 is connected via the vehicle body 8 having a large heat capacity. It may be cooled. 1, 2, and 13 exemplify the case where the inverter 5 is disposed on the vehicle body 8 side of the rotating electrical machine 7, but the inverter 5 is naturally disposed on the wheel 9 side of the rotating electrical machine 7. May be. Since an empty space is formed in the central portion of the inverter 5, even when the inverter 5 is arranged on the wheel 9 side of the rotating electrical machine 7, the arrangement place of the rotating shaft of the rod 80 and the rotor 7r is secured.

  In the above description, a general two-level inverter is exemplified as the inverter 5 using FIG. 4, but a three-level inverter 5B as shown in FIG. 14 may be adopted. As shown in FIG. 14, the three-level inverter 5B can output the voltage at the intermediate point M, which is the intermediate point obtained by dividing the voltage Vdc between the positive and negative electrodes, in addition to the voltage at the positive electrode PV and the voltage at the negative electrode NV. The voltage Vdc between the positive and negative electrodes is ideally divided equally by the first capacitor 59P and the second capacitor 59N having the same rated capacity.

  Similarly to the two-level inverter 5, the inverter 5B is configured by a three-leg (5U, 5V, 5W) bridge circuit corresponding to each of the three phases. One leg includes four IGBTs (Q1, Q2, Q3, Q4) connected in series between the positive electrode PV and the negative electrode NV, and a connection point between the two IGBTs Q1 and Q2 on the positive electrode PV side and the negative electrode NV. Two diodes D5 and D6 connected in series with the direction from the negative electrode NV to the positive electrode PV as the forward direction are formed between the connection points of the two IGBTs Q3 and Q4 on the side. The connection point of the two diodes is connected to the intermediate point M.

  A series circuit of one leg constituted by four IGBTs (Q1, Q2, Q3, Q4) includes an upper arm 5P connected in series on the positive electrode PV side and a lower stage connected in series on the negative electrode NV side. It is comprised from the arm 5N. A connection point between the upper arm 5P and the lower arm 5N in the series circuit of four IGBTs is connected to each stator coil of the rotating electrical machine 7. Each IGBT (Q1, Q2, Q3, Q4) is provided with a flywheel diode (D1, D2, D3, D4), respectively. The flywheel diode is connected in parallel to the IGBT such that the cathode terminal is connected to the collector terminal of the IGBT and the anode terminal is connected to the emitter terminal of the IGBT.

  As described above, one IGBT module 3 includes one IGBT 5Q constituted by six IGBT chips 3Q and two diode chips 3D connected in parallel as flywheel diodes 5D of the IGBT 5Q ( (See FIG. 7). The upper arm 5P of the three-level inverter 5B shown in FIG. 14 can be composed of two IGBT modules 3. Therefore, the upper arm 5P for three lines of the U, V, and W phases can be configured with the same arrangement as in FIG. Similarly, the lower arm 5N for three lines of U, V, and W phases can be configured with the same arrangement as in FIG. Here, one of the two diode chips 3D functioning as the flywheel diode 5D in the set of IGBT modules 3 of the arms 5P and 5N can function as the biasing diodes D5 and D6. In this way, the inverter-integrated rotating electrical machine 7 in which the three-level inverter 5B is integrated can be constructed by stacking two substrates on which the IGBT modules 3 are arranged in a regular hexagonal shape.

  Note that the circuit configuration of the three-level inverter is not limited to that illustrated in FIG. For the sake of simplification, only the U-phase leg is illustrated, but the present invention can also be applied to a circuit configuration as shown in FIG. In FIG. 15A, the bias diodes D5 and D6 are IGBTs Q5 and Q6, and in FIG. 15B, the bias diodes D7 and D8 are IGBTs Q7 and Q8. In other words, since there are two pairs of bias diodes and IGBTs in one leg, there are six pairs in three legs.

  One pair can be constituted by the IGBT module 3 as shown in FIGS. Therefore, six pairs of biasing diodes and IGBTs can be configured using the six IGBT modules 3. The six IGBT modules 3 can be arranged in a ring shape as shown in FIG. In the case of the three-level inverter 5B shown in FIG. 14, it has been described that the inverter-integrated rotating electrical machine 7 can be constructed by laminating two substrates on which the IGBT modules 3 are arranged in a regular hexagonal shape. When the circuit configuration of the three-level inverter shown in FIG. 15 is adopted, the inverter-integrated rotating electrical machine 7 can be configured by stacking three substrates. Since the ring-shaped inverter can be formed thin with respect to the axial center direction of the rotor 7r, a plurality of substrates can be easily stacked even if the circuit configuration of the inverter increases. In addition to the three-level inverter, a substrate that constitutes a converter or the like can be stacked.

  As described above, according to the present invention, there is provided a vehicle drive device capable of individually driving wheels with a structure that can be easily deployed in a conventional automobile without increasing the unsprung load of the suspension device. can do.

1: Wheel suspension 5: Inverter 5U, 5V, 5W: Leg 6: Heat sink 7r: Rotor 7s: Stator 7: Rotary electric machine (inverter-integrated rotary electric machine)
8: Car body 9: Wheel 18: Spring

Claims (7)

A wheel suspension with a spring that is installed between the wheel and the vehicle body and softens vibrations in a predetermined vibration suppression direction;
An inverter-integrated dynamoelectric machine in which an inverter that converts electric power between DC power and three-phase AC power is provided adjacent to a stator along a rotation axis of a rotor, the center of the wheel suspension in the vibration suppression direction The inverter-integrated dynamoelectric machine having the rotating shaft of the rotor coaxially with the shaft, the lower end on the wheel side being installed on the vehicle body side than the lower end on the wheel side of the spring;
A vehicle drive device comprising: a power transmission mechanism that converts a rotation direction of the inverter-integrated rotating electrical machine into a rotation direction of the wheel and transmits a driving force of the inverter-integrated rotating electrical machine to the wheels.   The vehicle drive device according to claim 1, wherein each of the three-phase legs of the inverter is divided into regions in the circumferential direction of the stator.   The vehicle drive device according to claim 1, wherein the inverter-integrated rotating electrical machine is disposed inside the spring of the wheel suspension.   The vehicle drive device according to claim 1, wherein the inverter is provided on the vehicle body side of the inverter-integrated rotating electrical machine.   5. The vehicle drive device according to claim 1, wherein the inverter-integrated rotating electrical machine further includes a heat sink adjacent to the inverter along a rotation axis of the rotor.   6. The vehicle drive device according to claim 5, wherein the heat sink is connected to the vehicle body.   The vehicle drive device according to any one of claims 1 to 6, wherein the inverter includes an empty space that circulates around a central axis that is coaxial with the rotation axis of the rotor.

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