JP3432977B2 - Electric drive device for vehicle - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric drive device for a vehicle such as an electric wheelchair in which left and right drive wheels are individually driven by motors. [0002] As an electric drive device for this type of vehicle,
As disclosed in Japanese Patent Laid-Open No. 5-261132, there is a type in which a driving motor is attached to a boss or hub at the center of a driving wheel, and power is transmitted from the motor to the driving wheel by a planetary gear mechanism. In this apparatus, a vehicle travel command is issued by a joystick operated by a passenger, and the main processor outputs a command signal for controlling driving of the left and right drive wheels based on an input signal generated from the joystick. The command signal is taken into two electric motor processors provided for each driving wheel, and each electric motor processor controls driving of a corresponding motor. In this way, the vehicle speed is changed and steered by individually changing and controlling the rotational speed of the drive wheels. In this electric drive apparatus, the main processor is provided on a vehicle base (a chair part in the case of a wheelchair), and each electric motor processor is disposed near a corresponding motor and attached to a boss. . Each motor processor is at least partially housed in a boss and incorporated in a drive portion, which eliminates the need for a large number of control conductors, and is convenient for repair. However, in the above publication, it is not clarified what parts are provided as the main processor and the motor processor. If these are configured as a CPU (central processing unit), the CPUs are arranged in three places, and the manufacturing cost increases. Furthermore, if so, if an electric motor processor is installed in the vicinity of the motor and incorporated in the drive part, the CPU's operating performance will be required unless a CPU with high heat resistance is used due to heat generated in the drive part such as the motor. Can not ensure the reliability. C with high heat resistance
PU is generally expensive. The present invention has been made in view of the above circumstances, and an object thereof is to provide an electric drive device for a vehicle that is less affected by heat generated by a motor or the like and has high operational performance reliability. In order to solve the above problems, in the electric drive apparatus for a vehicle according to the present invention, the left and right drive wheels are individually driven by a motor, and the rotational speed of the drive wheels is determined. In an electric drive device for a vehicle that changes and steers a vehicle by separately changing the vehicle speed, a hub that is rotatably attached to an axle is provided at the center of each drive wheel, and the hub is formed hollow. , has an opening towards the side, a high thermal conductivity metal lid covering the opening is attached to the axle, the motor for the corresponding driving wheel in the lid The opposite side of the hub
Is fixed at a position offset with respect to the axle, and is connected to the drive gear of the motor and the drive gear.
A gear case that houses a plurality of reduction gears is provided with the lid.
The gear is fixed to a surface facing the inner side of the hub of the body and the gear with respect to the axle of the surface facing the inner side of the hub of the lid
The power control unit of the motor is fixed on the opposite side of the case, and the vehicle has a travel command unit that is operated manually,
A main control unit, and the main control unit controls the power control unit based on an input signal from the travel command unit. In this configuration, the lid to which the motor and the power control unit are fixed is made of metal having high thermal conductivity.
The effect of dissipating heat generated by the motor and heat generated by the power control unit is great. The power control unit is connected to the gear case with respect to the axle.
Is mounted on the opposite side, i.e., away from the motor. Therefore, it is possible to prevent the power control unit from being overheated and damaged while the motor and the power control unit are attached to the same lid. Moreover, the electric power control part is being fixed to the surface which faces the hub inner side of a cover body.
This leads to the fact that the outer surface of the lid with good heat dissipation is not blocked from the outside air by the power control unit. Also by this, it is possible to suppress overheating of the power control unit. Further, by using the lid as a heat sink in this manner, it is not necessary to provide a special heat sink or a cooling device separately. DETAILED DESCRIPTION OF THE INVENTION A. First Embodiment Configuration of Embodiment A-1. Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing a control system of an electric drive device for a vehicle according to an embodiment. In the figure, reference numeral 1 is an operation panel for passengers, and 2 is an operation panel for assistants. Reference numeral 3 is a DC power source comprising a storage battery, 4, 5 are motors for rotating left and right drive wheels, and 6, 7 are motors 4, 5 respectively.
It is the electric power control part which drives rotation of. The motors 4 and 5 are respectively provided with rotary encoders 8 and 9 for detecting their rotational speed. Each power control unit 6, 7
A current is supplied from the power source 3. Reference numeral 10 denotes a main controller (main control unit), and the main controller 10 includes hardware such as a CPU 11 and a memory. The operation panels 1 and 2 are provided with main switches 1a and 2a for opening and closing circuits for supplying current to the main controller 10, respectively. The main controller 10 is energized from the power supply 3 when either one of the main switches 1a and 2a is turned on. The occupant operation panel 1 is provided with a joystick (travel command unit) 1b. As will be described later, when changing the vehicle speed and steering the electric wheelchair, when the joystick 1b is tilted, the speed of each drive wheel is controlled so that the electric wheelchair advances in that direction. That is, if the occupant tilts the joystick 1b forward, it moves forward, backwards if it tilts backward, turns left if it tilts left, turns right if it tilts right,
The motors 4 and 5 are rotated. Further, the joystick 1b always keeps the non-operating state at the neutral position unless the occupant touches it. The operation panel 2 for the assistant is provided with a forward / reverse button (running command section) 2b. The forward / backward button 2b is a seesaw-type button that tilts forward and backward, and the motors 4 and 5 are rotated so that the forward movement is performed when the assistant pushes the front and the backward movement when the backward is pushed. The forward / reverse button 2b
Will always remain in a neutral position unless touched by a caregiver. CP built in the main controller 10
U11 operates based on a predetermined program and performs various functions. That is, the CPU 11 has an operation panel 1,
In accordance with the on / off signals supplied from the two main switches 1a and 2a, it is determined which of the travel command signals for the joystick 1b and the forward / reverse button 2b should be selected.
Based on the travel command signal of the joystick 1b or the forward / reverse button 2b selected based on this determination, the speed at which each drive wheel should be rotated is calculated. As a result of the calculation of the speed, when any of the driving wheels is stopped, that is, when the speed should be “0”, the CPU 11 controls the power control unit 6.
Alternatively, a signal for turning off 7 is output. Thereby, one of the motors 4 and 5 stops. When the speed calculation result is other than the above, the CPU 11 calculates the target vehicle speed and outputs a gate signal as a control signal based on the target vehicle speed. Each power control unit 6, 7 has a plurality of FETs,
These FET drive circuits are included. Among these, the drive circuit is directly conducted from the power source 3. CPU 1
By operating the FET with the gate signal from 1,
The amount of power applied to the corresponding motor 4 or 5 is controlled,
The rotational speed of the motor 4 or 5, that is, the speed of each drive wheel is controlled. Thus, the advancing direction of the electric wheelchair is changed by changing the left and right speeds. Further, the CPU 11 receives the pulses input from the rotary encoders 8 and 9, calculates the actual speed of each driving wheel, and feedback-controls the gate signal. In the present embodiment, after both main switches 1a and 2a are turned off, the CPU 11 determines the travel command signal for the joystick 1b or the forward / reverse button 2b of the main switch 1a or 2a that is turned on first. Is preferentially selected. This priority selection state is reset when both the main switches 1a and 2a are turned off, and the priority is given to the traveling command signal of the joystick 1b forward / reverse button 2b of the main switch 1a or 2a that is turned on next. It is made to choose. The operation panels 1 and 2 are provided with indicator lamps 17 which are turned on when the corresponding joystick 1b or forward / reverse button 2b is selected. Further, the operation panels 1 and 2 are provided with a warning lamp 18 that is turned on when an abnormality occurs in the control system.
In 0, a warning buzzer 19 is also provided that similarly issues a warning when an abnormality occurs. The indicator lamp 17 and the warning lamp 18 are LE
D. The indicator light 17, the warning light 18, and the warning buzzer 19 are operated by the CPU 11. A-2. Next, the configuration of the electric wheelchair that is a vehicle according to the embodiment will be described. FIG. 2 is a left side view showing a state in which a passenger M is riding on the electric wheelchair 21, and FIG. 3 is a rear view of the electric wheelchair 21. The electric wheelchair 21 includes a foldable frame 22 formed by assembling pipes, a seat 23 provided on the frame 22 on which a passenger M sits, a front wheel 24 and a drive wheel provided in a pair of left and right before and after the frame 22. 25
With. A passenger operation panel 1 is disposed at the front of the frame 22, and a battery pack 27 incorporating a power source 3 is disposed at the rear. Two handles 28 held by the assistant are provided at the upper rear part of the frame 22, and the operation panel 2 for the assistant is attached to one handle 28. Further, in the lower rear part of the frame 22, the auxiliary wheel 2 that prevents the seat 23 from excessively tilting backward.
9 is provided. The seat 23 is constituted by a seat stretched between the left and right pipes constituting the frame 22.
The front wheel 24 is a caster type idler wheel. Drive wheel 25
Consists of a rim 25a and a tire 25b attached to the rim 25a, and is connected to a hub portion 30 arranged in the center by a large number of radially arranged spokes 26. As shown in FIG. 5, the hub portion 30 has a bottomed cylindrical shape with a shallow bottom, that is, a hollow hub body (hub) 3.
1 is provided. The hub body 31 has an opening toward the side, and the opening is covered with a disk-shaped lid 35. At the center of the hub body 31 is a boss 32.
The axle 34 is mounted on the boss 32 via two bearings 33. The axle 34 is fitted to a part of the frame 22 and is fixed by a nut 37. The drive wheel 25 is rotatably supported by the frame 22. The lid body 35 is fitted and fixed to the axle 34, and a slight gap is left between the lid body 35 and the hub body 31. This gap is formed in a labyrinth shape to prevent intrusion of water or the like. In this way, the axle 34
The lid 35 is fixed integrally with the frame 22, while the drive wheel 25 rotates together with the hub body 31. In the hub portion 30 described above, a hub body 31 is provided.
Is formed from a material having high strength such as high carbon steel or stainless steel to support the drive wheel 25, and the lid 35 is formed from a material having high thermal conductivity such as an aluminum alloy or a copper alloy. . As shown in FIGS. 2 and 3, a manual ring 36 located outside the drive wheel 25 is integrally fixed to the hub body 31. This manual ring 3
6 is used when the user M travels by manually rotating the drive wheel 25. Now, the drive wheel 25 is rotationally driven by a drive mechanism 40 provided in the hub portion 30. As shown in FIGS. 4 and 6, the drive mechanism 40 includes the lid 3 of the hub portion 30.
5 and a plurality of (in this case, two) reduction gears 43 and 44 connected to a drive gear 42 of the motor 4 or 5. It consists of and. The drive shaft 42a of the drive gear 42 and the gear shafts 43a and 44a of the reduction gears 43 and 44 are respectively connected to a cover body 35 and a gear case 45 screwed to the inner surface of the cover body 35.
The drive gear 42 and the reduction gears 43 and 44 are housed in a gear case 45, which is rotatably supported via a bearing 46. The tip of the gear shaft 44 a of the downstream reduction gear 44 protrudes from the gear case 45, and a pinion gear 47 is provided at the protruding end. Is meshed with the internal gear 30a, which is an internal tooth. The gear case 45 is formed in a substantially arc shape so as to surround the axle 34 in a state of being fixed to the lid 35, and the motor 4 or 5 is an end of the gear case 45, with respect to the axle 34. It is disposed at an offset position. In this way, the drive mechanism 40 forms a planetary gear mechanism. When the drive shaft 42a of the motor 4 or 5 rotates, the rotation is transmitted from the pinion gear 47 to the internal gear 30a via the reduction gears 43, 44, and thus the drive wheel 25.
Is designed to rotate. As shown in FIG. 4, the rotational speed of the drive shaft 42a of the motor 4 or 5 is detected by a rotary encoder 8 or 9 provided in the hub portion 30 and connected to the drive shaft 42a by a timing belt 48. It is like that. The rotary encoder 8 or 9 is arranged in parallel with the gear case 45 in the vicinity of the motor 4 or 5 and is bolted to the inner surface of the lid 35. The reduction gear 44 is provided with a clutch mechanism 60 that connects and disconnects a path for transmitting the driving force of the motors 4 and 5 to the hub body 31. The motor 4 or 5 of the drive mechanism 40 described above is a rectangular parallelepiped battery pack 27 (FIGS. 2 and 3).
Is the power source 3. The battery pack 27 incorporates a large number of rechargeable batteries, and is detachably loaded in the battery holder 110 attached to one (right side in this case) hub portion 30. The battery pack 27 is provided with a handle 102 for convenient attachment / detachment and carrying with respect to the battery holder 110. The battery holder 110 is bolted to the lid body 35 of the hub portion 30 together with the motor 5 and extends obliquely upward and rearward from the attachment portion to the lid body 35 as shown in FIG. A controller housing 111 and a battery housing 112 that opens upward are formed on the controller housing 111. The controller storage unit 111 includes the CPU described above.
11 stores a main controller 10 (see FIG. 1). At the base end of the battery holder 110,
A cylindrical motor cover 107 that is put on the motor 5 and is rotatable about the motor 5 is integrally formed, and together with the motor cover 107, the entire battery holder 110 is
It is designed to rotate in the front-rear direction. Further, as shown in FIGS. 4 and 5, the hub portion 30 receives power signals from the main controller 10 and controls power supplied to the motors 4 and 5 on the same side. The part 6 or 7 is covered and stored in the case 54. The power control unit 6 or 7 is disposed at a position away from the corresponding motor 4 or 5, and is attached to the surface of the lid 35 facing the inside of the hub body 31. As described above, each power control unit 6, 7 includes a plurality of FETs 52 made of semiconductor elements, and a drive circuit 51 for these FETs 52. Among these, the drive circuit 51 is disposed on the printed circuit board 50. The printed circuit board 50 is attached to a thin plate-like heat radiating plate 53 via a spacer 55, and the FET 5
2 is screwed directly to the heat sink 53. Heat sink 5
3 is formed of a material having high thermal conductivity such as an aluminum alloy or a copper alloy, like the lid 35. The entire surface of the heat radiating plate 53 is brought into direct contact with the lid 35 and is screwed to the lid 35. B. Operation and Effect of Embodiment In the above configuration, the motor 4 or 5 and the power control unit 6
Alternatively, since the lid 35 to which 7 is fixed is made of metal having high thermal conductivity, the heat generated by the motors 4 and 5 and the heat generated by the power control units 6 and 7 are greatly radiated. Further, the power control units 6 and 7 are attached at positions separated from the corresponding motors 4 and 5. Therefore, it is possible to prevent the power control units 6 and 7 from being overheated and damaged while the motor 4 or 5 and the power control unit 6 or 7 are attached to the same lid 35. The power control units 6 and 7 are fixed to the surface of the lid 35 facing the inside of the hub main body 31. This means that the outer surface of the lid 35 with good heat dissipation is the power control unit 6, 7.
It will lead to the fact that it will not be blocked from outside air.
Also by this, it is possible to suppress the power control units 6 and 7 from being overheated and damaged. Further, by using the lid 35 as a heat sink in this way, it is not necessary to provide a special heat sink or a cooling device separately. In the present embodiment, the heat radiating plate 53 is provided. However, as will be described later, this is due to another reason and may not be provided depending on circumstances. Furthermore, a CPU generally having a low heat resistance.
Reference numeral 11 denotes motors 4 and 5 and power control units 6 and 7 serving as heat generation sources.
Main controller 10 arranged at a position away from
Is provided. Therefore, the CPU 11 can perform a highly reliable control operation without being adversely affected by heat from the motors 4 and 5 and the power control units 6 and 7. And, in addition to the overheating being suppressed as described above, the power control units 6 and 7 are mainly composed of the FET 52 made of a semiconductor element and its drive circuit 51 instead of the CPU. A slight temperature rise will not degrade the operating performance. In each power control unit 6, 7, the FET 52 and its drive circuit 51 are attached to the heat radiating plate 53. Therefore, the FET 52
If the drive circuit 51 is assembled in advance to form a unit and then assembled to the lid 35, the assembly workability is improved. As shown in the figure, the heat dissipation plate 53 is a small member, but since the entire surface thereof is in close contact with the lid 35, the thermal conductivity to the lid 35 is good. As described above, according to the present invention, it is possible to provide an electric drive device for a vehicle that is less affected by heat generated by a motor or the like and has high operational performance reliability. .

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing a control system of an electric drive device for a vehicle according to an embodiment of the present invention. FIG. 2 is a left side view showing a wheelchair that is a vehicle according to the embodiment. FIG. 3 is a rear view of the wheelchair. FIG. 4 is a side view showing the inside of the hub of the drive wheel of the same embodiment. 5 is a cross-sectional view taken along line VV in FIG. 6 is a cross-sectional view taken along the line VI-VI in FIG. 4; FIG. 7 is a side view showing the battery pack and its holder used in the embodiment. [Explanation of symbols] 1 Operation panel for passengers, 2 Operation panel for assistants, 1b Joystick (running command unit), 2b Forward / backward button (running command unit), 3 Power supply, 4, 5 motor,
6, 7 Electric power control unit, 10 Main controller (main control unit), 11 CPU, 21 Electric wheelchair, 25 Drive wheel, 30 Hub part, 25a Rim, 25b Tire, 2
6 Spoke, 30a Internal gear, 31 Hub body (hub), 34 Axle, 35 Lid, 42 Drive gear, 4
3,44 Reduction gear, 50 Printed circuit board, 51 FE
T drive circuit, 52 FET, 53 heat sink

Claims (1)

(57) [Claims] [Claim 1] An electric drive device for a vehicle that changes the vehicle speed and steers by individually driving the left and right drive wheels with a motor and individually changing and controlling the rotational speed of the drive wheels. In the center of each drive wheel, a hub that is rotatably attached to the axle is provided, the hub is formed hollow, has an opening toward the side, and covers the opening. A metal cover body with high thermal conductivity is attached to the axle, and a motor for a corresponding drive wheel is a hub in the cover body .
Is offset with respect to the axle on the opposite side
Was is fixed in position, the drive gear of the motor and the
A gear that houses a plurality of reduction gears connected to the drive gear
The case is fixed to the surface of the lid facing the inside of the hub
And the axle of the surface of the lid facing the hub inside.
On the other hand, the electric power control unit of the motor is fixed on the side opposite to the gear case, and the vehicle is provided with a travel command unit that is operated manually, and a main control unit. An electric drive device for a vehicle, wherein the power control unit is controlled based on an input signal from a command unit.