Electric drive system, electric vehicle

Abstract

To provide an electric drive device that can simplify the configuration. [Solution] The electric drive system comprises motors 50A and 50B and reduction gears 70A and 70B. Motors 50A and 50B each include a rotor, a stator, and a power converter. Motors 50A and 50B and reduction gears 70A and 70B are integrated. The power converter is positioned on the opposite side of the drive wheel 31 in the direction in which the rotor shaft extends from the reduction gears 70A and 70B.

Description

Technical Field

[0001] The present invention relates to an electric drive device and an electric vehicle including the electric drive device.

Background Art

[0002] As this type of device, as described in Patent Document 1, a device in which a motor and a speed reduction device are integrated is known.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In order to drive a motor, a power converter electrically connected to the stator winding of the motor is required. When the power converter and the motor are separate, the wiring for electrically connecting the motor and the power converter becomes complicated, and the configuration of the electric drive device may become complicated.

[0005] The main object of the present invention is to provide an electric drive device capable of simplifying the configuration.

Means for Solving the Problems

[0006] A first invention is an electric drive device for rotating drive wheels (30, 202) of an electric vehicle, comprising: a rotor (52a), a stator (53) disposed opposite to the rotor in the radial direction, a power converter (60) electrically connected to the stator winding (53a) of the stator and configured to switch and control to flow a current through the stator winding, and a motor (50A, 50B) having the same, The device includes a motor-side rotating body (77) connected to the shaft (52b) of the rotor, and a drive-side rotating body (78b) connected to a drive shaft (31) that rotates the drive wheel, and a reduction device (70A, 70B, 70) that reduces the rotational speed of the drive-side rotating body relative to the motor-side rotating body, Equipped with, The motor and the reduction gear are integrated into one unit. The power converter is positioned relative to the reduction gear on the opposite side of the drive wheel in the direction in which the shaft extends. The second invention is an electric drive device for rotating the drive wheels (30,202) of an electric vehicle, Rotor (52a) and A stator (53) is arranged radially opposite to the rotor, A power converter (60) is electrically connected to the stator winding (53a) of the stator and is switched and controlled to supply current to the stator winding, A motor (50A, 50B) having the following: The device includes a motor-side rotating body (77) connected to the shaft (52b) of the rotor, and a drive-side rotating body (78b) connected to a drive shaft (31) that rotates the drive wheel, and a reduction device (70A, 70B, 70) that reduces the rotational speed of the drive-side rotating body relative to the motor-side rotating body, A braking device (92A) that applies braking force to the rotational power transmission path from the shaft to the drive shaft via the motor-side rotating body and the drive-side rotating body, Equipped with, The motor, the reduction gear, and the braking device are integrated into a single unit. The third invention is an electric vehicle (30,202) comprising a first electric drive unit for rotating one of the left and right drive wheels (30,202) and a second electric drive unit for rotating the other drive wheel, Each of the first electric drive unit and the second electric drive unit is: Rotor (52a) and A stator (53) is arranged radially opposite to the rotor, A power converter (60) is electrically connected to the stator winding (53a) of the stator and is switched and controlled to supply current to the stator winding, A motor (50A, 50B) having the following: The motor-side rotating body (77) is connected to the shaft (52b) of the rotor, and the drive-side rotating body (78b) is connected to the drive shaft (31) that rotates the drive wheel, and the reduction device (70A, 70B) reduces the rotational speed of the drive-side rotating body relative to the motor-side rotating body, Equipped with, In each of the first and second electric drive units, the motor and the reduction gear are integrated. The first electric drive unit and the second electric drive unit are arranged asymmetrically with respect to the vehicle's length. The fourth invention is an electric vehicle (30,202) comprising a first electric drive unit for rotating one of the left and right drive wheels (30,202) and a second electric drive unit for rotating the other drive wheel, Each of the first electric drive unit and the second electric drive unit is: Rotor (52a) and A stator (53) is arranged radially opposite to the rotor, A power converter (60) is electrically connected to the stator winding (53a) of the stator and is switched and controlled to supply current to the stator winding, A motor (50A, 50B) having the following: A reduction gear (70A, 70B) is provided, which has a motor-side rotating body (77) connected to the shaft (52b) of the rotor, and a drive-side rotating body (78b) that rotates the drive wheel, and reduces the rotational speed of the drive-side rotating body relative to the motor-side rotating body. Equipped with, In each of the first and second electric drive units, the motor and the reduction gear are integrated. By rotating the rotors of the first electric drive device and the second electric drive device respectively, the one driving wheel and the other driving wheel are rotated in the same direction, and the electric vehicle is turned by creating a difference between the rotational speed of the one driving wheel and the rotational speed of the other driving wheel, or By rotating the rotors of the first electric drive device and the second electric drive device respectively, the one driving wheel and the other driving wheel are rotated in opposite directions to turn the electric vehicle.

[0007] According to the above invention, the configuration of the electric drive device can be simplified.

Brief Description of Drawings

[0008] [Figure 1] Overall configuration diagram of an electric wheelchair according to the first embodiment. [Figure 2] Diagram showing the drive unit. [Figure 3] Diagram showing the internal structure of the motor and the reduction gear. [Figure 4] Diagram showing the motor part among the cross-sectional views taken along the line 4-4 of FIG. 3. [Figure 5] Diagram showing the electrical configuration of the drive unit. [Figure 6] Diagram showing the drive unit according to a modification of the first embodiment. [Figure 7] Diagram showing a state where a shaft is inserted through the through hole of the control board. [Figure 8] Diagram showing the drive unit according to the second embodiment. [Figure 9] Diagram showing the drive unit according to a modification of the second embodiment. [Figure 10] Diagram showing the drive unit according to a modification of the second embodiment. [Figure 11] Diagram showing the braking device according to a modification of the second embodiment. [Figure 12] Overall configuration diagram of a senior car according to the third embodiment. [Figure 13] Diagram showing the drive unit. [Figure 14] Diagram showing the internal structure of the reduction gear. [Figure 15] Overall configuration diagram of the automated guided vehicle according to the fourth embodiment. [Figure 16] A diagram showing the drive unit. [Figure 17] A diagram showing an automated guided vehicle (AGV) in a forward-moving position. [Figure 18] A diagram showing an automated guided vehicle in a braking state. [Figure 19] A diagram showing an automated guided vehicle (AGV) in a rotating position. [Figure 20] A diagram showing a drive unit according to another embodiment. [Figure 21] A diagram showing a drive unit according to another embodiment. [Figure 22] A diagram showing a drive unit according to another embodiment. [Modes for carrying out the invention]

[0009] <First Embodiment> Hereinafter, a first embodiment of the electric drive system according to the present invention applied to a small mobility device will be described with reference to the drawings. The small mobility device in this embodiment is an electric wheelchair as an electric vehicle.

[0010] As shown in Figure 1, the electric wheelchair 10 comprises a frame 11 and a seat 12 fixed to the frame 11. The seat 12 comprises a seat portion 12a and a backrest portion 12b. The electric wheelchair 10 also comprises armrests 13 and footrests 14 fixed to the frame 11.

[0011] The electric wheelchair 10 is a four-wheeled wheelchair comprising a bracket portion 21 attached to the front of the vehicle frame 11, left and right front wheels 20 attached to the bracket portion 21, and left and right rear wheels 30. In this embodiment, the left and right front wheels 20 serve as steering wheels.

[0012] The electric wheelchair 10 is equipped with a drive unit 40. The drive unit 40 has a housing 41 fixed to the vehicle frame 11. The housing 41 is located below the seat 12a.

[0013] The electric wheelchair 10 is equipped with a control unit 25 operated by the user. The control unit 25 is fixed to the armrest 13. In this embodiment, the control unit 25 is an upward-extending joystick. The control unit 25 is a component that instructs the electric wheelchair 10 to move forward, backward, or turn.

[0014] Figure 2 illustrates the internal configuration of the housing 41 of the drive unit 40.

[0015] The housing 41 includes a first motor 50A, a first reduction gear 70A, a second motor 50B, a second reduction gear 70B, and a power storage unit 42. The power storage unit 42 is, for example, a secondary battery such as a lithium-ion battery. In Figure 2, an example is shown in which the power storage unit 42 is located on the front side of the housing 41, but this is not the only example.

[0016] The first motor 50A and the first reduction gear 70A are integrated to form the first electric drive unit, and the second motor 50B and the second reduction gear 70B are integrated to form the second electric drive unit. In this embodiment, the configuration of the first electric drive unit is basically the same as that of the second electric drive unit. For this reason, the first electric drive unit will be used as an example to explain the following using Figures 3 and 4. Figure 4 is a cross-sectional view showing the portion of the first motor 50A in the cross-sectional view taken along line 4-4 in Figure 3.

[0017] First, let's describe an example of the first motor 50A. The first motor 50A includes a rotor 52a containing field poles (e.g., permanent magnets), a shaft 52b fixed to the rotor 52a, and a stator 53 positioned radially outward from the rotor 52a. The stator 53 includes a stator core and stator windings 53a (see Figure 5) wound around the stator core.

[0018] The first motor 50A is equipped with a motor housing 54. The motor housing 54 comprises a cylindrical portion 54a, a first connecting portion 54b, a second connecting portion 54c, and a cover portion 54d. The cylindrical portion 54a is cylindrical in the direction in which the shaft 52b extends. The first connecting portion 54b is provided at the first end of the cylindrical portion 54a in the longitudinal direction, and the second connecting portion 54c is provided at the second end. The rotor 52a and the stator 53 are housed in the cylindrical space enclosed by the cylindrical portion 54a, the first connecting portion 54b, and the second connecting portion 54c. The stator 53 is provided on the inner circumferential surface of the cylindrical portion 54a. Note that in Figure 2, etc., the boundary portion between the first connecting portion 54b and the cylindrical portion 54a of the motor housing 54 is not shown.

[0019] A first opening 54b1 is formed in the first connecting portion 54b, and a first motor bearing 55b is provided in the first opening 54b1. A second opening 54c2 is formed in the second connecting portion 54c, and a second motor bearing 55b is provided in the second opening 54c2. In this embodiment, each motor bearing 55a, 55b is a rolling bearing comprising an inner ring, an outer ring, and rollers. The first end of the shaft 52b is rotatably supported by the motor bearing 55a, and the second end of the shaft 52b is rotatably supported by the second motor bearing 55b.

[0020] A cover portion 54d is provided on the side of the second connection portion 54c opposite to the cylindrical portion 54a in the longitudinal direction of the motor housing 54. A control board 56 is arranged in the space enclosed by the second connection portion 54c and the cover portion 54d. In this embodiment, the control board 56 is positioned so that its surface is perpendicular to the direction in which the shaft 52b extends. A connector opening 54d1 is formed in the cover portion 54d. A connector 57, electrically connected to the control board 56, is inserted through the connector opening 54d1. The connector 57 includes a power connector and a communication connector.

[0021] Thus, in this embodiment, a control board 56 on which the rotor 52a, stator 53, and inverter 60 are mounted is housed in a motor housing 54 integrated with the first reduction gear 70A. Therefore, the wiring that electrically connects the stator winding 53a and the inverter 60 can also be housed in the motor housing 54, simplifying the configuration of the electric drive system.

[0022] Next, I will explain the first reduction gear 70A.

[0023] The first reduction gear 70A includes a housing 71. The housing 71 includes a peripheral wall portion 72. The peripheral wall portion 72 includes a first wall portion 73 and a second wall portion 74 that are opposite each other in the horizontal direction. The housing 71 includes a bottom plate portion 75 and a top plate portion 76. The bottom plate portion 75 is provided at the lower end of the peripheral wall portion 72, and the top plate portion 76 is provided at the upper end of the peripheral wall portion 72. The housing 71 has a rectangular parallelepiped shape with its longitudinal direction perpendicular to the direction in which the motor housing 54 extends.

[0024] The longitudinal end of the first wall portion 73 is connected to the first connection portion 54b by a fastening member such as a bolt. A first drive-side opening 73a is formed in the portion of the first wall portion 73 facing the first connection portion 54b. As a result, the space inside the housing 71 and the space inside the motor housing 54 are connected by the first opening 54b1 and the first drive-side opening 73a, which are designated as the "motor-side opening".

[0025] An example of the internal structure of the housing 71 will be described. The first end of the shaft 52b extends through the first opening 54b1 and the first drive-side opening 73a into the space inside the housing 71. Multiple spur gears are housed in the space enclosed by the peripheral wall portion 72, the bottom plate portion 75, and the top plate portion 76. Specifically, the motor-side rotating body 77, the first gear 78a, and the second gear 78b are housed in this space. They are arranged in the order of motor-side rotating body 77, first gear 78a, and second gear 78b from the side of the first drive-side opening 73a. The first end of the shaft 52b is connected to the motor-side rotating body 77.

[0026] The first wall portion 73 and the second wall portion 74 are provided with a first bearing 79a and a second bearing 79b (corresponding to the "drive-side rotating body"). In this embodiment, each bearing 79a and 79b is a rolling bearing comprising an inner ring, an outer ring, and rollers. The first gear 78a is rotatably supported by the first bearing 79a, and the second gear 78b is rotatably supported by the second bearing 79b. The rotational axes of the motor-side rotating body 77, the first gear 78a, and the second gear 78b extend in the same direction as the shaft 52b extends.

[0027] The external teeth of the motor-side rotating body 77 are configured to mesh with the external teeth of the first gear 78a, and the diameter of the motor-side rotating body 77 is smaller than the diameter of the first gear 78a. Also, the external teeth of the first gear 78a are configured to mesh with the external teeth of the second gear 78b, and the diameter of the first gear 78a is smaller than the diameter of the second gear 78b. In other words, the diameter of each gear housed in the housing 71 increases in the longitudinal direction of the housing 71 from the side of the first drive-side opening 73a to the side of the second drive-side opening 80. As a result, the rotational speed of the second gear 78b relative to the motor-side rotating body 77 is reduced, and the input torque of the motor-side rotating body 77 is amplified and output from the second gear 78b. Furthermore, because the motor-side rotating body 77, the first gear 78a, and the second gear 78b are spur gears, the dimensions of the first reduction gear 70A in the vehicle width direction can be reduced, and consequently, the dimensions of the electric wheelchair 10 in the vehicle width direction can be reduced. Reducing the width of the vehicle helps alleviate the constraints on the movement of the electric wheelchair 10 in narrow spaces such as elevator doors. This improves convenience for users of the electric wheelchair 10 (e.g., those requiring care).

[0028] A second drive-side opening 80 is formed in the portion of the second wall 74 where the second bearing 79b is installed. A drive shaft 31 is inserted through the second drive-side opening 80. The drive shaft 31 extends in the same direction as the shaft 52b. A second gear 78b is connected to the first end of the drive shaft 31, and a rear wheel 30 is connected to the second end.

[0029] The electric drive system of this embodiment is configured to reduce the dimensions in the vehicle width direction. As shown in Figure 2, the side of the housing 71 of the first reduction gear 70A facing the drive shaft 31 in the longitudinal direction and the side of the housing 71 of the second reduction gear 70B facing the drive shaft 31 in the longitudinal direction are opposite each other in the direction in which the shaft 52b extends (vehicle width direction). In addition, the drive shaft 31 of the first reduction gear 70A and the drive shaft 31 of the second reduction gear 70B are coaxial. The left rear wheel 30 is connected to the drive shaft 31 of the first reduction gear 70A, and the right rear wheel 30 is connected to the drive shaft 31 of the second reduction gear 70B.

[0030] In the housing 71 of the first reduction gear 70A, the side facing the drive shaft 31 in the longitudinal direction faces the side circumferential surface of the motor housing 54 of the second motor 50B (specifically, the outer circumferential surface of the cylindrical portion 54a, the second connecting portion 54c, and the cover portion 54d). Similarly, in the housing 71 of the second reduction gear 70B, the side facing the drive shaft 31 faces the side circumferential surface of the motor housing 54 of the first motor 50A in the longitudinal direction. This allows the dimensions of the electric drive unit in the vehicle width direction to be reduced.

[0031] Next, the electrical configuration of the first motor 50A and the second motor 50B will be explained using Figure 5.

[0032] The first motor 50A is equipped with an inverter 60 as a power converter. The inverter 60 is equipped with three phase upper and lower arm switches SW. In this embodiment, the switches SW are voltage-controlled semiconductor switching elements, specifically SiC N-channel MOSFETs. Therefore, in the switches SW, the high-potential terminal is the drain and the low-potential terminal is the source. The switches SW have a body diode. Note that the switches SW may also be, for example, IGBTs. In this case, in the switches SW, the high-potential terminal is the collector and the low-potential terminal is the emitter.

[0033] In each phase, the drain of the upper arm switch SW is connected to the first terminal of the smoothing capacitor 61. In each phase, the source of the upper arm switch SW is connected to the drain of the lower arm switch SW. In each phase, the source of the lower arm switch SW is connected to the second terminal of the smoothing capacitor 61. In each phase, the source of the upper arm switch SW and the drain of the lower arm switch SW are connected to the first terminal of the stator winding 53a. The second terminal of the stator winding 53a in each phase is connected to the neutral point.

[0034] The second motor 50B, like the first motor 50A, is equipped with an inverter 60 and a smoothing capacitor 61. The configuration of the second motor 50B is basically the same as that of the first motor 50A. Therefore, a detailed explanation of the second motor 50B will be omitted as appropriate.

[0035] The first terminal of the smoothing capacitor 61 constituting each inverter 60 is connected to the positive terminal of the energy storage unit 42 via a power connector included in the connector 57 and a first power cable 58a. The second terminal of the smoothing capacitor 61 constituting each inverter 60 is connected to the negative terminal of the energy storage unit 42 via a power connector and a second power cable 58b. Note that the energy storage unit 42 may be provided individually for each inverter 60.

[0036] The first motor 50A includes a microcontroller 62 (corresponding to the "control unit"), a sensor 63, and a drive IC 64. In this embodiment, the drive IC 64 is provided individually for each switch SW. The sensor 63 includes an angle sensor that detects the rotational angle position (electrical angle) of the first motor 50A and a current sensor that detects the current flowing through the stator winding 53a. The detected value from the sensor 63 is input to the microcontroller 62.

[0037] The microcontroller 62 controls the switching of each switch SW constituting the inverter 60 in order to control the control amount of the first motor 50A to a command value based on each detected value. The microcontroller 62 generates drive signals corresponding to the upper arm switch SW and the lower arm switch SW in order to alternately turn on the upper arm switch SW and the lower arm switch SW in each phase. The microcontroller 62 outputs the generated drive signals to the drive IC 64. The microcontroller 62, drive IC 64 and inverter 60 are provided on the control board 56. The microcontroller 62 of the second motor 50B controls the switching of each switch SW constituting the inverter 60 of the second motor 50B in order to control the control amount of the second motor 50B to a command value.

[0038] A higher-level ECU 43 is located inside the enclosure 41. Input signals from the operation unit 25 are input to the higher-level ECU 43. The higher-level ECU 43 exchanges information with the microcontrollers 62 of each motor 50A and 50B via the communication connectors that make up the connectors 57 of each motor 50A and 50B.

[0039] The higher-level ECU 43 transmits command values ​​for control variables to the microcontrollers 62 of each motor 50A, 50B via a communication connector, so that desired control such as driving control of the electric wheelchair 10 can be achieved. The control variables are, for example, torque, the rotational speed (or electrical angular velocity) of the rotor 52a, or the rotational angular position of the rotor 52a.

[0040] For example, if the higher-level ECU 43 determines, based on the input signal from the control unit 25, that the electric wheelchair 10 is instructed to move in a straight line, it sends rotation speed command values ​​to the microcontrollers 62 of each motor 50A and 50B so that the left and right rear wheels 30 are driven to rotate in the same direction and at the same rotation speed.

[0041] For example, if the higher-level ECU 43 determines, based on the input signal from the control unit 25, that the electric wheelchair 10 is instructed to turn, it rotates the left and right rear wheels 30 in the same direction and sends rotation speed command values ​​to the microcontrollers 62 of each motor 50A, 50B so that the rotation speed of the rear wheel 30 in the instructed turning direction is lower than the rotation speed of the remaining rear wheel 30. For example, if a right turn is instructed, the rotation speed command value of the right rear wheel 30 is set lower than the rotation speed command value of the left rear wheel 30. The higher-level ECU 43 can also send rotation speed command values ​​to the microcontrollers 62 of each motor 50A, 50B so that the left and right rear wheels 30 rotate in opposite directions. In this case, the electric wheelchair 10 will perform a pivot turn.

[0042] For example, when the electric wheelchair 10 is traveling uphill, if the higher-level ECU 43 determines, based on the input signal from the control unit 25, that the electric wheelchair 10 is instructed to stop, it sends command values ​​for the rotational angle position to the microcontrollers 62 of each motor 50A and 50B so as to stop the rotation of the rotors 52a that make up the first and second motors 50A and 50B. As a result, when the joystick is not operated by the user, the rotational angle position is fixed to the command value, and hill-hold control of the electric wheelchair 10 is implemented.

[0043] For example, if the higher-level ECU 43 determines that braking of the electric wheelchair 10 is instructed, it sends torque command values ​​to the microcontrollers 62 of each motor 50A and 50B so that braking torque is generated in each motor 50A and 50B. As a result, braking force is applied to the electric wheelchair 10, and the electric wheelchair 10 then comes to a stop.

[0044] As described in detail above, this embodiment makes it possible to provide a highly convenient electric wheelchair 10 while simplifying the configuration of the drive unit 40.

[0045] <Modified form of the first embodiment> Taking the first motor 50A as an example, as shown in Figure 6, the control board 56 may be located on the side of the first reduction gear 70A in the longitudinal direction of the motor housing 54, while the rotor 52a and stator 53 may be located on the side opposite to the first reduction gear 70A in the longitudinal direction. In this case, as shown in Figure 7, it is sufficient that a through hole 56a is formed in the control board 56 through which the shaft 52b is inserted.

[0046] The drive unit 40 does not necessarily need to be equipped with a higher-level ECU 43. In this case, for example, the microcontrollers 62 of each motor 50A and 50B can communicate with each other, and one microcontroller 62 can function as the master and the other microcontroller 62 can function as the slave.

[0047] <Second Embodiment> The second embodiment will now be described, focusing on the differences from the first embodiment, with reference to the drawings. In this embodiment, as shown in Figure 8, the housing 41 houses the first braking device 90A and the second braking device 90B. In the diagrams of the second embodiment, components that are the same as those shown in Figure 2 and other earlier figures are denoted by the same reference numerals for convenience.

[0048] The first braking device 90A is integrated with the first reduction gear 70A, and the second braking device 90B is integrated with the second reduction gear 70B. In this embodiment, each of the braking devices 90A and 90B is an electromagnetic brake. However, the braking device is not limited to an electromagnetic brake.

[0049] The first braking device 90A is connected to the portion of the first wall 73 that constitutes the housing 71 of the first reduction gear 70A, which faces the drive shaft 31. The second braking device 90B is connected to the portion of the first wall 73 that constitutes the housing 71 of the second reduction gear 70B, which faces the drive shaft 31. In other words, each braking device 90A and 90B is positioned in a space sandwiched between each reduction gear 70A and 70B in the vehicle width direction, and between each motor 50A and 50B in the vehicle length direction. This makes it possible to reduce the size of the housing 41.

[0050] In this embodiment, the first braking device 90A applies braking force by contacting the second gear 78b or drive shaft 31 of the first reduction gear 70A. The second braking device 90B applies braking force by contacting the second gear 78b or drive shaft 31 of the second reduction gear 70B.

[0051] The first braking device 90A is controlled by the microcontroller 62 of the first motor 50A, and the second braking device 90B is controlled by the microcontroller 62 of the second motor 50B. Specifically, the higher-level ECU 43, based on the input signal from the operation unit 25, outputs a braking command to the microcontrollers 62 of each motor 50A and 50B when it determines that the operation unit 25 is not being operated. When the microcontroller 62 of the first motor 50A receives a braking command, it controls the first braking device 90A to apply braking force to the second gear 78b or drive shaft 31 of the first reduction gear 70A. When the microcontroller 62 of the second motor 50B receives a braking command, it controls the second braking device 90B to apply braking force to the second gear 78b or drive shaft 31 of the second reduction gear 70B. As a result, when the user of the electric wheelchair 10 stops operating the joystick, which is the operation unit 25, the electric wheelchair 10 stops due to the brakes.

[0052] <Modified form of the second embodiment> As shown in Figure 9, in the first electric drive unit, the first braking device 91A may be connected to the second wall portion 74 that constitutes the housing 71. In this case, the first braking device 91A applies braking force to the drive shaft 31. The same applies to the second electric drive unit.

[0053] As shown in Figure 10, in the first electric drive unit, a first braking device 92A may be connected between the first reduction gear 70A and the motor housing 54 of the first motor 50A. In this case, the first braking device 92A may, for example, contact the shaft 52b to apply braking force. The same applies to the second electric drive unit.

[0054] With this configuration, braking force is applied to the shaft 52b before it is decelerated by the reduction gear, thus reducing the braking force that the braking device needs to apply. This allows the size of the braking device to be reduced.

[0055] As shown in Figure 11, each electric drive unit may have a braking device provided within the housing 71 of the reduction gear. Specifically, the braking device includes a stopper member 94, which moves around the rotation axis to a first position shown by a solid line or a second position shown by a dashed line. When the stopper member 94 rotates to the first position, it engages with the external teeth of the motor-side rotating body 77, stopping the rotation of the motor-side rotating body 77. On the other hand, when the stopper member 94 rotates to the second position, it moves away from the motor-side rotating body 77, allowing the motor-side rotating body 77 to rotate. The rotational movement of the stopper member 94 can be controlled by a microcontroller 62.

[0056] <Third Embodiment> The third embodiment will now be described, focusing on the differences from the first embodiment, with reference to the drawings. As shown in Figure 12, the small mobility device of this embodiment is a senior car as an electric vehicle. The users of the senior car are, for example, elderly people. In the figures of the third embodiment, the same reference numerals are used for the same components as those shown in Figure 2 and other figures for convenience.

[0057] The electric vehicle 100 is equipped with a body frame 101. The left and right front wheels 110 are located on the front side of the body frame 101. The left and right rear wheels 120 are located on the rear side of the body frame 101. A handle unit 140, which serves as an operating unit for steering the electric vehicle 100, is located above the front wheels 110. The front wheels 110 are attached to the body frame 101 via axles and suspensions 111 (not shown). The rear wheels 120 are attached to the body frame 101 via axles and suspensions 121 (not shown). In this embodiment, the left and right front wheels 110 are steering wheels, and the left and right rear wheels 120 are drive wheels that are rotationally driven by a drive unit described later.

[0058] The electric vehicle 100 is equipped with a seat 130, the seat 130 comprising a seat portion 130a and a backrest portion 130b.

[0059] The electric vehicle 100 is equipped with a drive unit fixed to the vehicle frame 101. Figure 13 shows the configuration inside the housing 41 that constitutes the drive unit of this embodiment. The drive unit has a configuration corresponding to the first electric drive device of the first embodiment, and does not have a configuration corresponding to the second electric drive device. In the configuration shown in Figure 13, the motor 50 corresponds to the first motor 50A, and the reduction gear 70 corresponds to the first reduction gear 70A.

[0060] Figure 14 shows an example of the internal structure of the housing 71 that constitutes the reduction gear 70.

[0061] A third drive-side opening 81 is formed in the portion of the first wall 73 where the second bearing 79b is provided. The third drive-side opening 81 is formed in the first wall 73 at a position opposite to the second drive-side opening 80 in the direction in which the shaft 52b extends. A drive shaft 31 extending from the side of the second drive-side opening 80 is inserted through the third drive-side opening 81. A second gear 78b is connected to the middle portion of the drive shaft 31. The left rear wheel 120 is connected to the first end of the drive shaft 31, and the right rear wheel 120 is connected to the second end.

[0062] Furthermore, the higher-level ECU 43 transmits command values ​​for the control amount of the motor 50 to the microcontroller 62 of the motor 50, similar to the first embodiment. This enables the electric vehicle 100 to perform straight-line driving, turning, and other maneuvers, similar to the first embodiment.

[0063] <Fourth Embodiment> The fourth embodiment will now be described, focusing on the differences from the first and third embodiments, with reference to the drawings. As shown in Figure 15, the small mobility device in this embodiment is an automated guided vehicle (AGV) 200 as an electric vehicle. In the diagrams of the fourth embodiment, components that are the same as those shown in Figures 2, 13, etc., are given the same reference numerals for convenience.

[0064] The automated guided vehicle 200 comprises a vehicle body 201 and a plurality of drive wheels 202. In this embodiment, the plurality of drive wheels 202 are the left and right front wheels and the left and right rear wheels.

[0065] As shown in Figure 16, the housing 210 of the drive unit of the automated guided vehicle 200 contains an electric drive device corresponding to each drive wheel 202. However, the reduction gear 70 that constitutes the electric drive device differs from the reduction gear shown in Figure 2 in that the drive shaft 31 and the shaft 52b are coaxial. In this case, the reduction gear 70 is, for example, a reduction gear equipped with a planetary gear mechanism or a cycloidal gear mechanism.

[0066] The microcontroller 62 of each motor 50 is configured to communicate with a higher-level ECU 43 (not shown) via a communication connector that constitutes the connector 57.

[0067] When the higher-level ECU 43 determines that the automated guided vehicle 200 is instructed to travel in a straight line, it sends a rotation speed command value to the microcontroller 62 of each motor 50 so that the left and right drive wheels 202 are driven to rotate in the same direction and at the same rotation speed, as shown in Figure 17.

[0068] When the higher-level ECU 43 determines that braking of the automated guided vehicle 200 is instructed, it sends a torque command value to the microcontroller 62 of each motor 50 so that braking torque is generated in each motor 50, as shown in Figure 18. As a result, braking force is applied to the automated guided vehicle 200, and the automated guided vehicle 200 then comes to a stop.

[0069] When the higher-level ECU 43 determines that the automated guided vehicle 200 is instructed to turn, it rotates the left and right drive wheels 202 in the same direction and sends a rotation speed command value to the microcontroller 62 of each motor 50 so that the rotation speed of the drive wheel 202 in the instructed turning direction is lower than the rotation speed of the remaining drive wheels 202. In the example shown in Figure 19, the higher-level ECU 43 determines that the automated guided vehicle 200 is instructed to turn to the right and sends a rotation speed command value to the microcontroller 62 of each motor 50 so that the rotation speed of the right drive wheel 202 is lower than the rotation speed of the left drive wheel 202.

[0070] Furthermore, the higher-level ECU 43 can also send rotation speed command values ​​to the microcontrollers 62 of each motor 50 so that the left and right drive wheels 202 rotate in opposite directions. In this case, the automated guided vehicle 200 will perform a pivot turn.

[0071] <Other Embodiments> Furthermore, each of the above embodiments may be implemented with the following modifications.

[0072] The configuration of the electric drive unit shown in Figure 16 may be changed to the configuration shown in Figure 20. Specifically, in the motor housing 54, the reduction gear 70, control board 56, rotor 52a, and stator 53 are arranged in that order from the drive shaft 31 side.

[0073] Furthermore, as shown in Figure 21, a braking device 90 that applies braking force to the drive shaft 31 may be connected to the reduction gear 70. Also, in a configuration that includes a reduction gear 70, as shown in Figure 22, the braking device 90, reduction gear 70, rotor 52a, stator 53, and control board 56 may be arranged in that order from the drive shaft 31 side.

[0074] The electric drive devices of each embodiment described above can be used as appropriate in electric wheelchairs, mobility scooters, and automated guided vehicles. For example, in an automated guided vehicle or mobility scooter, the left and right front wheels may be driven by the electric drive device of the first embodiment, and the left and right rear wheels may be driven by the electric drive device of the first embodiment. Alternatively, in a mobility scooter, the left and right front and rear wheels may be driven by the electric drive device shown in Figure 16. In this case, the mobility scooter can also be made to turn in a tight spot.

[0075] The drive component connected to the drive shaft of the reduction gear is not limited to the wheel; for example, it may be a sprocket component. In this case, rotational power may be transmitted from the sprocket component to the drive wheel via a chain or belt, for example.

[0076] The motor housing is not limited to a cylindrical shape; for example, it may have a rectangular cross-section.

[0077] The motor is not limited to an inner rotor type; an outer rotor type is also acceptable.

[0078] The connector is not limited to one in which the communication connector and power connector are integrated. The communication connector and power connector may be provided separately.

[0079] The control unit and its method described herein may be implemented by a dedicated computer provided by configuring a processor and memory programmed to perform one or more functions embodied by a computer program. Alternatively, the control unit and its method described herein may be implemented by a dedicated computer provided by configuring a processor by one or more dedicated hardware logic circuits. Alternatively, the control unit and its method described herein may be implemented by one or more dedicated computers configured by a combination of a processor and memory programmed to perform one or more functions and a processor configured by one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by the computer on a computer-readable non-transitional tangible recording medium. [Explanation of symbols]

[0080] 50A, 50B...1st and 2nd motors, 52a...rotor, 52b...shaft, 53...stator, 53a...stator windings, 54...motor housing, 60...inverter, 70A, 70B...1st and 2nd reduction gears, 77...motor-side rotating body, 78a, 78b...1st and 2nd gears.

Claims

1. An electric drive device for rotating the drive wheels (30, 202) of an electric vehicle, Rotor (52a) and A stator (53) is arranged radially opposite to the rotor, A power converter (60) is electrically connected to the stator winding (53a) of the stator and is controlled by switching to supply current to the stator winding, A motor (50A, 50B) having the following: The device includes a motor-side rotating body (77) connected to the shaft (52b) of the rotor, and a drive-side rotating body (78b) connected to a drive shaft (31) that rotates the drive wheel, and a reduction device (70A, 70B, 70) that reduces the rotational speed of the drive-side rotating body relative to the motor-side rotating body, Equipped with, The motor and the reduction gear are integrated into one unit. The power converter is an electric drive device, which is positioned relative to the reduction gear on the opposite side of the drive wheel in the direction in which the shaft extends.

2. An electric drive device for rotating the drive wheels (30, 202) of an electric vehicle, Rotor (52a) and A stator (53) is arranged radially opposite to the rotor, A power converter (60) is electrically connected to the stator winding (53a) of the stator and is controlled by switching to supply current to the stator winding, A motor (50A, 50B) having the following: The device includes a motor-side rotating body (77) connected to the shaft (52b) of the rotor, and a drive-side rotating body (78b) connected to a drive shaft (31) that rotates the drive wheel, and a reduction device (70A, 70B, 70) that reduces the rotational speed of the drive-side rotating body relative to the motor-side rotating body, A braking device (92A) that applies braking force to the rotational power transmission path from the shaft to the drive shaft via the motor-side rotating body and the drive-side rotating body, Equipped with, An electric drive system in which the motor, the reduction gear, and the braking gear are integrated.

3. The electric drive device according to claim 2, wherein the power converter is positioned on the opposite side of the drive wheel in the direction in which the shaft extends, relative to the braking device.

4. An electric vehicle (30,202) comprising a first electric drive unit for rotating one of the left and right drive wheels (30,202), and a second electric drive unit for rotating the other drive wheel, Each of the first electric drive unit and the second electric drive unit is: Rotor (52a) and A stator (53) is arranged radially opposite to the rotor, A power converter (60) is electrically connected to the stator winding (53a) of the stator and is controlled by switching to supply current to the stator winding, A motor (50A, 50B) having the following: The motor-side rotating body (77) is connected to the shaft (52b) of the rotor, and the drive-side rotating body (78b) is connected to the drive shaft (31) that rotates the drive wheel, and the reduction device (70A, 70B) reduces the rotational speed of the drive-side rotating body relative to the motor-side rotating body, Equipped with, In each of the first and second electric drive units, the motor and the reduction gear are integrated. An electric vehicle in which the first electric drive unit and the second electric drive unit are arranged asymmetrically with respect to the vehicle's length.

5. The drive shaft of the first electric drive unit and the drive shaft of the second electric drive unit are coaxial. The motor of the first electric drive unit is positioned rearward in the vehicle length direction with respect to the drive shaft of the first electric drive unit. The electric vehicle according to claim 4, wherein the motor of the second electric drive unit is positioned at a location offset forward in the vehicle length direction with respect to the drive shaft of the second electric drive unit.

6. An electric vehicle (30,202) comprising a first electric drive unit for rotating one of the left and right drive wheels (30,202), and a second electric drive unit for rotating the other drive wheel, Each of the first electric drive unit and the second electric drive unit is: Rotor (52a) and A stator (53) is arranged radially opposite to the rotor, A power converter (60) is electrically connected to the stator winding (53a) of the stator and is controlled by switching to supply current to the stator winding, A motor (50A, 50B) having the following: A reduction gear (70A, 70B) is provided, which has a motor-side rotating body (77) connected to the shaft (52b) of the rotor, and a drive-side rotating body (78b) that rotates the drive wheel, and reduces the rotational speed of the drive-side rotating body relative to the motor-side rotating body. Equipped with, In each of the first and second electric drive units, the motor and the reduction gear are integrated. By rotating the rotors of the first and second electric drive units, the one drive wheel and the other drive wheel are made to rotate in the same direction, and the electric vehicle is turned by creating a difference between the rotational speed of the one drive wheel and the rotational speed of the other drive wheel, or An electric vehicle that rotates the first electric drive unit and the second electric drive unit, respectively, by rotating the rotors of the two units, thereby causing one drive wheel and the other drive wheel to rotate in opposite directions and causing the electric vehicle to turn.

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