JP2020048611A - Single-seat electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a single-seater electric vehicle having improved running performance. A single-seater electric vehicle 1 according to an embodiment includes a seat 3 on which an occupant sits, armrests 31L and 31R on which an occupant rests his / her arms, a footboard 8 on which an occupant rests his / her feet, and front / rear wheels 4L / 4R. At least four wheels, including 5L and 5R, at least two electric motors 60L and 60R that drive at least two of the wheels independently of each other, and an independent suspension front suspension 40 that supports the front wheels 4L and 4R. , With an independent suspension rear suspension 50 that supports the rear wheels 5L and 5R. The arms 41L, 41R, 42L and 42R of the independent suspension front suspension 40 have a valgus angle when no occupant is on board. [Selection diagram] Fig. 1

Description

  The present invention relates to a single-seat electric vehicle that runs using an electric motor.

  BACKGROUND ART A handle-type electric wheelchair is known as a single-seat electric vehicle for the elderly (for example, Patent Document 1). The handle-type electric wheelchair may be referred to as a senior car (registered trademark).

  The handle-type electric wheelchair can travel on a relatively flat pavement. For example, an elderly person can move between a home and a store and do shopping by riding in a steering wheel-type electric wheelchair.

JP 2004-255968 A

  In order to widen the range in which an occupant in a steering wheel-type electric wheelchair can move, it is desired that the vehicle can travel on a rough road such as an unpaved road.

  The present invention provides a single-seat electric vehicle with improved running performance.

  The single-seat electric vehicle according to the embodiment of the present invention has a seat on which an occupant sits, an armrest on which the occupant places an arm, a footboard on which the occupant places a foot, and at least four wheels including a front wheel and a rear wheel. Comprising at least two electric motors for driving at least two of the wheels independently of each other, an independent suspension front suspension for supporting the front wheels, and an independent suspension rear suspension for supporting the rear wheels, When the occupant is not in the vehicle, the arm of the independent suspension front suspension has a dihedral angle.

  A single-seat electric vehicle according to an embodiment of the present invention includes an independently suspended front suspension and an independently suspended rear suspension, and drives at least two wheels independently of each other using at least two electric motors. As a result, it is possible to improve the ability to follow the unevenness of the road surface and to stably transmit the driving force to the road surface. In addition, the turning performance of the vehicle can be improved. The arm of the independently suspended front suspension has a dihedral angle. As a result, the minimum ground clearance of the vehicle can be increased, and the stroke amount of the suspension can be increased. According to the present invention, for example, the traveling performance of a vehicle on an unpaved road can be improved. Further, for example, it is possible to make it easier for the vehicle to get over a step.

  According to one embodiment, the single-seat electric vehicle includes a steering wheel on which the occupant performs steering, a steering column provided on a transmission path that transmits an operation of the steering wheel by the occupant to the front wheels, and a steering column. The vehicle may further include a head tube that passes through the inside of the head tube, and a suspension tower to which an upper portion of the front suspension is attached. The suspension tower may be provided on the head tube.

  A high strength is required for the frame portion to which the suspension is attached because the impact received by the suspension from the road surface is transmitted. When the suspension tower is provided near the left and right ends of the vehicle body frame, it is necessary to secure high strength in a frame portion extending in the left and right direction from the center in the vehicle width direction, and the weight of the vehicle body increases. Providing the suspension tower in the head tube located near the center in the vehicle width direction eliminates the need for the above-described high-strength frame portion extending in the left-right direction, and can reduce the weight of the vehicle body.

  According to one embodiment, an upper part of the rear suspension may be attached to the seat.

  Since a frame portion for attaching the upper portion of the rear suspension to the vehicle body frame is not required, the vehicle body structure can be simplified.

  According to one embodiment, a front end of the front wheel may be located at the forefront of the single-seat electric vehicle.

  It is possible to prevent the body frame and the body cover from contacting an obstacle such as a step located in front of the vehicle before the front wheels. When the front wheels first contact the obstacle in front of the vehicle, the obstacle can be easily overcome. For example, even a relatively high step can be overcome.

  According to one embodiment, a rear end of the rear wheel may be located at the rearmost position of the single-seat electric vehicle.

  It is possible to prevent the body frame and the body cover from coming into contact with an obstacle such as a step located behind the vehicle before the rear wheel. When the rear wheels first contact the obstacle behind the vehicle, the obstacle can be easily overcome. For example, even a relatively high step can be overcome.

  According to one embodiment, the at least two electric motors may be in-wheel motors.

  There is no need to secure a space for arranging the electric motor and the power transmission mechanism in the body of the vehicle, so that space can be saved. Further, since a drive shaft extending in the left-right direction of the vehicle is not required, the suspension is not restricted by the drive shaft. In addition, by controlling the driving force of each wheel independently using the in-wheel motor, the running performance of the vehicle can be improved.

  According to one embodiment, the rear suspension may be a trailing arm type suspension in which a pivot axis is located forward of a rotation axis of the rear wheel.

  Thereby, the stroke amount of the rear suspension can be increased. Further, since the suspension arm is not located near the center of the vehicle rear, a space can be secured near the center of the vehicle rear. The space near the center behind the vehicle can be used as, for example, luggage storage. It is possible to realize a single-seat electric vehicle with high luggage, which has sufficient luggage storage space.

  According to one embodiment, a height of the pivot shaft when the rear suspension is in a full bump state may be equal to or higher than a height of a rotation shaft of the rear wheel.

  Thereby, even when the rear suspension is in the full bump state, the force by which the rear suspension presses the rear wheel against the road surface can be secured, and the transmission loss of the driving force to the road surface can be reduced.

  According to one embodiment, the front suspension may be a double wishbone suspension.

  As a result, a change in the camber angle when the front wheel moves up and down can be reduced, and a stable grip force of the front wheel can be secured, and the riding comfort can be improved.

  According to an embodiment, the double wishbone suspension may have an upper arm, a lower arm, and a shock absorber, and the shock absorber may be attached to the upper arm.

  Thereby, interference between the knuckle arm of the steering system and the shock absorber can be suppressed. The turning angle of the front wheels can be increased, and the minimum turning radius of the vehicle can be reduced.

  According to one embodiment, the height of the rotation axis of the front wheel when the front suspension is fully extended is equal to or less than the minimum ground clearance of the single-seat electric vehicle, and the front suspension is in a full bump state. At this time, the height of the rotation axis of the front wheel may be equal to or higher than the height of the upper surface of the foot board.

  Due to the large stroke amount of the front suspension, it is easy to maintain a stable vehicle posture when traveling on a road surface with severe unevenness or over a step.

  According to one embodiment, the height of the rotation axis of the rear wheel when the rear suspension is fully extended is equal to or less than the minimum ground clearance of the single-seat electric vehicle, and the rear suspension is in a full bump state. The height of the rotation axis of the rear wheel at a certain time may be higher than the height of the upper surface of the foot board.

  Due to the large stroke amount of the rear suspension, a stable vehicle posture can be easily maintained when traveling on a road surface with severe unevenness or over a step.

  According to one embodiment, the single-seat electric vehicle may be a handle-type electric wheelchair.

  As a result, a steering wheel-type electric wheelchair with improved running performance is realized, and the occupant in the steering wheel-type electric wheelchair can have a wider range of action.

  A single-seat electric vehicle according to an embodiment of the present invention includes an independently suspended front suspension and an independently suspended rear suspension, and drives at least two wheels independently of each other using at least two electric motors. As a result, it is possible to improve the ability to follow the unevenness of the road surface and to stably transmit the driving force to the road surface. In addition, the turning performance of the vehicle can be improved. The arm of the independently suspended front suspension has a dihedral angle. As a result, the minimum ground clearance of the vehicle can be increased, and the stroke amount of the suspension can be increased. According to the embodiment of the present invention, for example, the traveling performance of a vehicle on an unpaved road can be improved. Further, for example, it is possible to make it easier for the vehicle to get over a step.

FIG. 1 is a perspective view of an electric vehicle according to an embodiment of the present invention as viewed obliquely from the front left. It is the perspective view which looked at the chassis structure of the electric vehicle concerning the embodiment of the present invention from diagonally left front. FIG. 1 is a perspective view of an electric vehicle according to an embodiment of the present invention as viewed obliquely from the rear right. FIG. 2 is a perspective view of the chassis structure of the electric vehicle according to the embodiment of the present invention, as viewed from obliquely right rear. 1 is a front view of an electric vehicle according to an embodiment of the present invention. (A) and (b) are top views of a steering mechanism provided in the electric vehicle according to the embodiment of the present invention. 1 is a block diagram illustrating an electric vehicle according to an embodiment of the present invention. 1 is a side view of an electric vehicle showing a front end position of a front wheel and a rear end position of a rear wheel according to an embodiment of the present invention. (A) is a side view showing the electric vehicle in a state where the suspension according to the embodiment of the present invention is fully extended, and (b) is a side view showing the electric vehicle in a state where the occupant according to the embodiment of the present invention is in the vehicle. (C) is a side view showing the electric vehicle when the suspension according to the embodiment of the present invention is in a full bump state. 1 is a side view of an electric vehicle in which a rear suspension according to an embodiment of the present invention is in a full bump state.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same components are denoted by the same reference numerals, and the description thereof will be omitted if they are duplicated. The following embodiment is an exemplification, and the present invention is not limited to the following embodiment.

  In the following description, front, rear, upper, lower, left, and right mean front, rear, upper, lower, left, and right, respectively, as viewed from an occupant seated on a seat of an electric vehicle.

  FIG. 1 is a perspective view showing a single-seat electric vehicle 1 according to an embodiment of the present invention. In the example shown in FIG. 1, the single-seat electric vehicle 1 is a four-wheel steering wheel-type electric wheelchair. In addition, the one-seat electric vehicle 1 according to the embodiment of the present invention is not limited to the four-wheeled handle-type electric wheelchair exemplified here. The one-seat electric vehicle 1 according to the embodiment of the present invention may be a joystick-type electric wheelchair. Also, the number of wheels may be more than four.

  FIG. 2 is a perspective view illustrating a chassis structure of the electric vehicle 1. FIG. 3 is a perspective view of the electric vehicle 1 as viewed obliquely from the rear right. FIG. 4 is a perspective view of the chassis structure of the electric vehicle 1 as viewed obliquely from the rear right. FIG. 5 is a front view of the electric vehicle 1.

  The electric vehicle 1 includes a body frame 2 (FIGS. 2 and 4). A head tube 22 is provided on the down tube 21 of the body frame 2. The head tube 22 rotatably supports a steering column 26 (FIGS. 1 and 3) passing therethrough. A steering wheel 6 on which an occupant performs steering is provided at an upper end of the steering column 26. An accelerator operator 7 is provided on the handle 6.

  An independent suspension front suspension 40 is provided at a front portion 23 of the body frame 2. In this example, the front suspension 40 is a double wishbone type suspension.

  The front suspension 40 has an upper arm 41L, a lower arm 42L, and a shock absorber 43L. One end of the upper arm 41L and one end of the lower arm 42L are rotatably supported by the front portion 23 of the body frame 2. The other end of the upper arm 41L and the other end of the lower arm 42L rotatably support the left front wheel 4L via a knuckle arm 47L (FIG. 4).

  Further, the front suspension 40 has an upper arm 41R, a lower arm 42R, and a shock absorber 43R. One end of the upper arm 41R and one end of the lower arm 42R are rotatably supported by the front portion 23 of the body frame 2. The other end of the upper arm 41R and the other end of the lower arm 42R rotatably support the right front wheel 4R via a knuckle arm 47R (FIG. 2). In some drawings, the coil springs of the shock absorbers 43L and 43R may be omitted in order to clearly illustrate the structure of the electric vehicle 1.

  The head tube 22 is provided with suspension towers 48L and 48R. An upper portion 44L of the shock absorber 43L is rotatably supported by a suspension tower 48L. An upper portion 44R of the shock absorber 43R is rotatably supported by a suspension tower 48R. A lower portion 45L of the shock absorber 43L rotatably supports the upper arm 41L. A lower portion 45R of the shock absorber 43R rotatably supports the upper arm 41R.

  FIGS. 6A and 6B are top views schematically illustrating a steering mechanism provided in the electric vehicle 1. A pitman arm 49 is attached to a lower end of the steering column 26. Each of one end of the tie rod 46L and one end of the tie rod 46R is rotatably connected to the pitman arm 49. The other end of the tie rod 46L is rotatably connected to the knuckle arm 47L. The other end of the tie rod 46R is rotatably connected to the knuckle arm 47R.

  FIG. 6A shows the steering mechanism during straight running. When traveling on a curve, the occupant turns the steering wheel 6. Referring to FIG. 6B, the steering force generated by the occupant rotating handle 6 is transmitted to pitman arm 49 via steering column 26. The pitman arm 49 rotates about the steering column 26, and the steering force is transmitted to the front wheels 4L and 4R via the tie rods 46L and 46R and the knuckle arms 47L and 47R. The steering angles of the front wheels 4L and 4R change according to the transmitted steering force, and the electric vehicle 1 can travel while turning left or right.

  The body cover 34 (FIG. 1) is provided so as to cover the front part 23 of the body frame 2 and a part of the front suspension 40. The front wheels 4L and 4R are exposed without being covered with the body cover 34 and the cowl. Thereby, the occupant can easily visually recognize the positional relationship between the front wheels 4L and 4R and the obstacle on the road surface.

  The body cover 34 is provided with a front guard 35 and a front carrier 36. Luggage can be placed on the front carrier 36. Further, a basket for storing luggage may be attached to the front carrier 36. By arranging the front guard 35 in front of the occupant, the occupant can obtain a sense of security during traveling. Further, the front guard 35 can be used as a luggage carrier.

  A seat 3 on which an occupant sits is provided at a rear portion 25 of the body frame 2. The seat 3 is provided with armrests 31L and 31R on which the occupant rests his / her arms and a backrest 32 on which the occupant leans. Armrests 31L and 31R also serve as side guards. A battery 10 is arranged behind the seat 3. By arranging the battery 10 at the end of the vehicle around the seat 3, the occupant can easily attach and detach the battery 10.

  A foot board 8 on which an occupant places his / her feet is provided on a bottom portion 24 of the body frame 2. The footboard 8 is anti-slip processed. The upper surface of the footboard 8 has a substantially flat shape so that the occupant can easily get on and off.

  An independent suspension rear suspension 50 is provided below the rear portion 25 of the body frame 2. In this example, the rear suspension 50 is a trailing arm type suspension.

  The rear suspension 50 has a trailing arm 51L and a shock absorber 53L. The rear suspension 50 has a trailing arm 51R and a shock absorber 53R. In some drawings, the coil springs of the shock absorbers 53L and 53R may be omitted in order to clearly illustrate the structure of the electric vehicle 1.

  The front portions of the trailing arms 51L and 51R are rotatably supported on the rear portion 25 of the body frame 2 by a pivot shaft 56. The seat 3 on which the occupant sits has a seat frame 33 (FIG. 4). The seat frame 33 is fixed to the rear part 25 of the body frame 2. In this example, each of the upper part 54L of the shock absorber 53L and the upper part 54R of the shock absorber 53R is rotatably supported by the seat frame 33. A lower portion 55L of the shock absorber 53L rotatably supports the trailing arm 51L. A lower portion 55R of the shock absorber 53R rotatably supports the trailing arm 51R. A stabilizer 57 is provided on each of the trailing arms 51L and 51R.

  An electric motor 60L (FIG. 4) is provided at the rear of the trailing arm 51L. The electric motor 60L is an in-wheel motor, and the electric motor 60L is provided with a left rear wheel 5L. The rear suspension 50 rotatably supports the left rear wheel 5L via an electric motor 60L. An electric motor 60R (FIG. 2) is provided at the rear of the trailing arm 51R. The electric motor 60R is an in-wheel motor, and the electric motor 60R is provided with a right rear wheel 5R. The rear suspension 50 rotatably supports the right rear wheel 5R via an electric motor 60R.

  The electric vehicle 1 of the present embodiment employs large front wheels and rear wheels 4L, 4R, 5L, and 5R. For example, the tire size of the front wheels and the rear wheels is 14 inches or more. This size is an example, and the present invention is not limited to this. By employing the large front and rear wheels, it is possible to improve the ability to travel on unpaved roads and steps.

  In the present embodiment, the rear wheels 5L and 5R are driven independently of each other by using two electric motors 60L and 60R. By independently controlling the rotation of the left and right wheels, the stability of the behavior of the electric vehicle 1 at the time of turning can be improved.

  Further, in a vehicle including a differential gear, there is a problem that when one of the driving wheels idles, the driving force is not easily transmitted to the other driving wheel. In the present embodiment, even if one of the rear wheels 5L and 5R idles, the other can exert a gripping force to stably continue running.

  Here, the two-wheel drive mode in which the electric motors 60L and 60R drive the rear wheels 5L and 5R is illustrated, but the electric vehicle 1 may be a four-wheel drive. In that case, an in-wheel motor is also provided for each of the front wheels 4L and 4R.

  The electric vehicle 1 of the present embodiment includes an independently suspended front suspension 40 and an independently suspended rear suspension 50. The rear wheels 5L and 5R are driven independently of each other by using the two electric motors 60L and 60R. As a result, it is possible to improve the ability to follow the unevenness of the road surface and to stably transmit the driving force to the road surface. In addition, the turning performance of the vehicle can be improved. According to the present embodiment, it is possible to enhance the running performance of the vehicle on an unpaved road or a step.

  Next, the angles of the upper arms 41L and 41R and the lower arms 42L and 42R will be described with reference to FIG.

At least when no occupant is in the vehicle, the upper arm 41L and the lower arm 42L are inclined so that the height gradually decreases from the center in the vehicle width direction (left-right direction) to the left. That is, the upper arm 41L and the lower arm _42L are provided with _dihedral angles θ _41L and θ _42L . Further, at least in a state where no occupant is in the vehicle, the upper arm 41R and the lower arm 42R are inclined so as to gradually decrease in height from the center in the vehicle width direction (lateral direction) to the right. That is, the upper arm 41R and the lower arm _42R are provided with _dihedral angles θ _41R and θ _42R . Thus, the minimum ground clearance of the electric vehicle 1 can be increased, and the stroke amount of the front suspension 40 can be increased. By increasing the minimum ground clearance and increasing the stroke of the suspension, the traveling performance of the vehicle on unpaved roads can be enhanced. In addition, the vehicle can easily get over the step.

  In this embodiment, the suspension towers 48L and 48R (FIG. 2) are provided on the head tube 22. The head tube 22 through which the steering column 26 passes is located near the center in the vehicle width direction. A high strength is required for the frame portion to which the suspension is attached because the impact received by the suspension from the road surface is transmitted. When the suspension towers 48L and 48R are provided near the left and right ends of the vehicle body, it is necessary to ensure high strength in a frame portion extending in the left-right direction from the center in the vehicle width direction, and the weight of the vehicle body increases. By providing the suspension towers 48L and 48R on the head tube 22 located near the center in the vehicle width direction, the above-described frame portion extending in the left-right direction with high strength becomes unnecessary, and the weight of the vehicle body can be reduced.

  In this embodiment, the shock absorbers 53L and 53R of the rear suspension 50 are attached to the seat frame 33 inside the seat 3. That is, the seat frame 33 also serves as a support member that supports the rear suspension 50. Since a frame portion for attaching the shock absorbers 53L and 53R to the vehicle body frame 2 becomes unnecessary, the vehicle structure can be simplified.

  The electric vehicle 1 also includes a double wishbone type front suspension 40. In the double wishbone suspension, the behavior of the suspension during a stroke, such as the camber angle, can be set to suit the vehicle. By adopting the double wishbone type front suspension 40, the change of the camber angle when the front wheels 4L and 4R move up and down is reduced, the stable grip force of the front wheels 4L and 4R is secured, and the riding comfort is improved. Can be done.

  In the front suspension 40, the shock absorbers 43L and 43R are attached to the upper arms 41L and 41R. When the shock absorbers 43L and 43R are attached to the lower arms 42L and 42R, the knuckle arms 47L and 47R may interfere with the shock absorbers 43L and 43R when the front wheels 4L and 4R have a large turning angle. By attaching the shock absorbers 43L and 43R to the upper arms 41L and 41R, interference between the knuckle arms 47L and 47R and the shock absorbers 43L and 43R can be suppressed. Thus, the turning angles of the front wheels 4L and 4R can be increased, and the minimum turning radius of the vehicle can be reduced.

  Further, the electric motors 60L and 60R of the present embodiment are in-wheel motors. Accordingly, it is not necessary to secure a space for disposing the electric motor and the power transmission mechanism in the body of the vehicle, so that space can be saved. Further, since a drive shaft extending in the left-right direction of the vehicle is not required, the suspension is not restricted by the drive shaft.

  In the trailing arm type rear suspension 50, the trailing arms 51L and 51R extend in the front-rear direction, and the pivot shaft 56 is located forward of the rotation axes of the rear wheels 5L and 5R. Thereby, the stroke amount of the rear suspension 50 can be increased. Further, since the trailing arm is not located near the center of the vehicle rear, a space can be secured near the center of the vehicle rear. The space near the center behind the vehicle can be used as, for example, luggage storage. The single-seat electric vehicle 1 with a high traveling property that secures a luggage storage space can be realized. Further, since there is a space near the center of the rear part of the vehicle, even if a large difference occurs between the left and right rear wheels 5L and 5R in the vertical direction in accordance with the operation of the independently suspended rear suspension 50, the vehicle body portion Can hardly contact the ground.

  Next, control of the electric motors 60L and 60R will be described with reference to FIG.

  The control device 70 controls the operation of the electric vehicle 1. The control device 70 is, for example, an MCU (Motor Control Unit). Typically, the control device 70 has a semiconductor integrated circuit such as a microcontroller or a signal processor capable of performing digital signal processing.

  The control device 70 includes an arithmetic circuit 71, a memory 72, and motor drive circuits 73L and 73R. Arithmetic circuit 71 controls the operation of electric motors 60L and 60R, and also controls the operation of each section of electric vehicle 1. The memory 72 stores a computer program that defines a procedure for controlling the operations of the electric motors 60L and 60R and each unit of the electric vehicle 1. The arithmetic circuit 71 reads a computer program from the memory 72 and performs various controls. The control device 70 is supplied with electric power from the battery 10.

  The accelerator operator 7 outputs a signal corresponding to the accelerator operation amount of the occupant to the arithmetic circuit 71. The steering angle sensor 81 is provided, for example, on the head tube 22 or the steering column 26, and outputs a signal corresponding to the rotation angle of the steering column 26 to the arithmetic circuit 71.

  The electric motor 60L is provided with a motor rotation sensor 61L. The motor rotation sensor 61L detects the rotation angle of the electric motor 60L, and outputs a signal corresponding to the rotation angle to the arithmetic circuit 71 and the motor drive circuit 73L. The arithmetic circuit 71 and the motor drive circuit 73L calculate the rotation speed of the electric motor 60L from the output signal of the motor rotation sensor 61L.

  The electric motor 60R is provided with a motor rotation sensor 61R. The motor rotation sensor 61R detects the rotation angle of the electric motor 60R, and outputs a signal corresponding to the rotation angle to the arithmetic circuit 71 and the motor drive circuit 73R. The arithmetic circuit 71 and the motor drive circuit 73R calculate the rotation speed of the electric motor 60R from the output signal of the motor rotation sensor 61R.

  The arithmetic circuit 71 generates a command value for generating an appropriate driving force from the output signal of the accelerator operator 7, the output signal of the steering angle sensor 81, the traveling speed of the vehicle, information stored in the memory 72, and the like. The calculated values are transmitted to the motor drive circuits 73L and 73R. The arithmetic circuit 71 can transmit different command values to the motor drive circuits 73L and 73R according to the running state of the vehicle.

  The motor drive circuits 73L and 73R are, for example, inverters. The motor drive circuit 73L supplies electric power according to the command value from the arithmetic circuit 71 from the battery 10 to the electric motor 60L. The motor drive circuit 73R supplies electric power according to the command value from the arithmetic circuit 71 from the battery 10 to the electric motor 60L. The rotation of the electric motors 60L and 60R supplied with electric power causes the rear wheels 5L and 5R to rotate. When the electric motors 60L and 60R include reduction gears, rotation is transmitted to the rear wheels 5L and 5R via the reduction gears.

  The arithmetic circuit 71 can detect the turning direction of the electric vehicle 1 from the output signal of the steering angle sensor 81. When the electric vehicle 1 turns left, different command values are transmitted to the motor drive circuits 73L and 73R so that the rotation speed of the rear wheel 5L is smaller than the rotation speed of the rear wheel 5R. When the electric vehicle 1 turns right, different command values are transmitted to the motor drive circuits 73L and 73R so that the rotation speed of the rear wheel 5R is smaller than the rotation speed of the rear wheel 5L. The difference between the rotation speeds of the rear wheel 5L and the rear wheel 5R may change according to the rotation angle of the steering column 26. For example, when the rotation angle of the steering column 26 is large, the difference between the rotation speeds of the rear wheels 5L and 5R may be increased. As described above, by independently controlling the rotation of the left and right wheels, the stability of the behavior of the electric vehicle 1 when turning can be improved.

  In addition, when the idling of one of the rear wheels 5L and 5R is detected, the arithmetic circuit 71 may perform control so as to reduce the rotation speed of the wheel that has slipped and to easily recover the grip force.

  In the above example, the electric vehicle 1 includes the steering angle sensor 81, but the electric vehicle 1 may not include the steering angle sensor 81. In that case, the turning direction and the turning radius may be estimated from the difference between the rotation speeds of the left and right electric motors 60L and 60R.

  Next, the front end position of the front wheels and the rear end position of the rear wheels in the electric vehicle 1 will be described.

  FIG. 8 is a side view of the electric vehicle 1. The front end positions of the front wheels 4L and 4R in the front-rear direction are indicated by broken lines 94. The front end position of a portion other than the front wheels in the electric vehicle 1 is indicated by a solid line 91. The member located at the forefront other than the front wheels is, for example, the body cover 34. In a form in which the front part of the frame is exposed, the front part of the frame may be a member located at the frontmost position other than the front wheels. In a mode in which the electric vehicle 1 includes a front bumper, a front basket, and the like, those members may be members located at the forefront other than the front wheels.

  In the present embodiment, the front ends of the front wheels 4L and 4R are located at the forefront of the electric vehicle 1. That is, the front ends of the front wheels 4L and 4R are located ahead of the front end positions of the portions other than the front wheels in the electric vehicle 1. Since the front wheels 4L and 4R are located at the forefront of the vehicle, it is possible to prevent the body cover 34 and the body frame 2 and the like from contacting an obstacle such as a step located in front of the vehicle before the front wheels 4L and 4R. it can. For example, at a height equal to or lower than the upper end portions of the front wheels 4L and 4R, the front ends of the front wheels 4L and 4R are located forward of the front end positions of portions other than the front wheels in the electric vehicle 1. Further, for example, the front ends of the front wheels 4L and 4R are located forward of the front end positions of portions other than the front wheels at a height equal to or lower than the rotation axis of the front wheels 4L and 4R. When the large front wheels 4L and 4R first contact the obstacle in front of the vehicle, the obstacle can be easily overcome. For example, even a relatively high step can be overcome.

  FIG. 8 shows the rear end positions of the rear wheels 5L and 5R in the front-rear direction by broken lines 95. A rear end position of a portion other than the rear wheels in the electric vehicle 1 is indicated by a solid line 92. The rearmost member other than the rear wheel is, for example, the seat 3. In a mode in which the electric vehicle 1 includes a rear bumper, a basket, and the like at a rear portion thereof, those members may be members located rearmost except for the rear wheels.

  In the present embodiment, the rear ends of the rear wheels 5L and 5R are located at the rearmost position of the electric vehicle 1. That is, the rear ends of the rear wheels 5L and 5R are located rearward of the rear end positions of portions other than the rear wheels in the electric vehicle 1. By arranging the rear wheels 5L and 5R at the rearmost position of the vehicle, it is possible to prevent another portion from contacting an obstacle such as a step located behind the vehicle before the rear wheels 5L and 5R. For example, at a height equal to or lower than the upper end portions of the rear wheels 5L and 5R, the rear ends of the rear wheels 5L and 5R are located rearward of the rear end positions of portions other than the rear wheels in the electric vehicle 1. Also, for example, the rear ends of the rear wheels 5L and 5R are located rearward of the rear end positions of portions other than the rear wheels at a height equal to or lower than the rotation axis of the rear wheels 5L and 5R. When the large rear wheels 5L and 5R first contact the obstacle behind the vehicle, the obstacle can be easily overcome. For example, even a relatively high step can be overcome.

  Next, the stroke amounts of the front suspension 40 and the rear suspension 50 will be described.

  FIG. 9 is a side view of the electric vehicle 1. FIG. 9A shows the electric vehicle 1 with the front suspension 40 and the rear suspension 50 fully extended. The state where the suspension is fully extended means a state where the weight of the vehicle and the occupant is not applied to the suspension. When the suspension is fully extended, the wheels are located at the lower end in the vertical width of the stroke. For example, a state where the vehicle body is suspended in the air and the suspension is completely lowered corresponds to a state where the suspension is fully extended. Further, for example, a state in which the shock absorber does not physically extend any more corresponds to a state in which the suspension is fully extended. FIG. 9B shows the electric vehicle 1 in a state where the occupant gets on the vehicle. FIG. 9C shows the electric vehicle 1 when the front suspension 40 and the rear suspension 50 are in a full bump state. The full bump state refers to a state in which the shock absorber of the suspension is most contracted. In the full bump state, the wheel is located at the upper end in the vertical width of the stroke. The minimum ground clearance of the electric vehicle 1 is indicated by a solid line 117. The height of the upper surface 108 of the footboard 8 is indicated by a broken line 118. The minimum ground clearance of the electric vehicle 1 is, for example, the height of the lowest position 107 of the body frame 2.

  When the front suspension 40 is fully extended (FIG. 9A), the height of the rotating shaft (rotation center) 104 of the front wheels 4L and 4R is equal to or less than the minimum ground clearance 117 of the electric vehicle 1. When the front suspension 40 is in the full bump state (FIG. 9C), the height of the rotating shaft 104 of the front wheels 4L and 4R is equal to or higher than the height 118 of the upper surface 108 of the footboard 8. As described above, the large stroke amount of the front suspension 40 makes it easy to maintain a stable vehicle posture when traveling on a road surface with severe unevenness or over a step.

  Further, when the rear suspension 50 is in a fully extended state (FIG. 9A), the height of the rotation shaft (rotation center) 105 of the rear wheels 5L and 5R is equal to or less than the minimum ground clearance 117 of the electric vehicle 1. . When the rear suspension 50 is in the full bump state (FIG. 9C), the height of the rotating shaft 105 of the rear wheels 5L and 5R is equal to or higher than the height 118 of the upper surface 108 of the footboard 8. As described above, the large stroke amount of the rear suspension 50 makes it easy to maintain a stable vehicle posture when traveling on a road surface with severe unevenness or over a step.

  Next, the relationship between the height of the pivot shaft 56 and the height of the rotating shaft 105 of the rear wheels 5L and 5R will be described.

  FIG. 10 is a side view of the electric vehicle 1 in which the rear suspension 50 is in a full bump state. The height of the rotating shaft 105 of the rear wheels 5L and 5R is indicated by a chain line 115. The height of the center 116 of the pivot shaft 56 when the rear suspension 50 is in the full bump state is equal to or higher than the height 115 of the rotating shaft 105 of the rear wheels 5L and 5R. In a state other than the full bump, it goes without saying that the height of the center 116 of the pivot shaft 56 is not less than the height 115 of the rotating shaft 105 of the rear wheels 5L and 5R. As described above, since the pivot shaft 56 is at a position higher than the rotation shaft 105 of the rear wheels 5L and 5R, the force by which the rear suspension 50 presses the rear wheels 5L and 5R against the road surface is ensured, and the driving force is applied to the road surface. Transmission loss can be reduced.

  The exemplary embodiments of the present invention have been described above.

  The electric vehicle 1 according to the embodiment includes a seat 3 on which an occupant sits, armrests 31L and 31R on which the occupant places arms, a footboard 8 on which the occupant places feet, and front and rear wheels 4L, 4R, 5L, and 5R. At least four wheels, at least two electric motors 60L and 60R for driving at least two of the wheels independently of each other, an independently suspended front suspension 40 supporting front wheels 4L and 4R, and rear wheels 5L and 5R. And an independently suspended rear suspension 50 that supports the rear suspension. When no occupant is in the vehicle, the arms 41L, 41R, 42L and 42R of the independently suspended front suspension 40 have a dihedral angle.

  The electric vehicle 1 according to the embodiment includes an independently suspended front suspension 40 and an independently suspended rear suspension 50, and drives at least two wheels independently of each other using at least two electric motors 60L and 60R. As a result, it is possible to improve the ability to follow the unevenness of the road surface and to stably transmit the driving force to the road surface. In addition, the turning performance of the vehicle can be improved. The arms 41L, 41R, 42L and 42R of the independently suspended front suspension 40 have a dihedral angle. As a result, the minimum ground clearance 117 of the vehicle can be increased, and the stroke amount of the suspension can be increased. According to the present invention, for example, the traveling performance of a vehicle on an unpaved road can be improved. Further, for example, it is possible to make it easier for the vehicle to get over a step.

  According to an embodiment, the electric vehicle 1 includes a steering wheel 6 on which an occupant performs steering, a steering column 26 provided on a transmission path for transmitting the operation of the steering wheel 6 by the occupant to the front wheels 4L and 4R, and a steering column 26. A head tube 22 passing therethrough and suspension towers 48L and 48R to which an upper part of the front suspension 40 is attached may be further provided. The suspension towers 48L and 48R may be provided on the head tube 22.

  A high strength is required for the frame portion to which the suspension is attached because the impact received by the suspension from the road surface is transmitted. When the suspension tower is provided near the left and right ends of the vehicle body frame, it is necessary to secure high strength in a frame portion extending in the left and right direction from the center in the vehicle width direction, and the weight of the vehicle body increases. In the present embodiment, by providing the suspension towers 48L and 48R on the head tube 22 located near the center in the vehicle width direction, the above-described high-strength frame portion extending in the left-right direction becomes unnecessary, and the vehicle weight is reduced. can do.

  According to an embodiment, the upper portions 54L and 54R of the rear suspension 50 may be attached to the seat 3. Since a frame portion for attaching the upper portions 54L and 54R of the rear suspension 50 to the vehicle body frame 2 is not required, the vehicle body structure can be simplified.

  According to an embodiment, the front ends of the front wheels 4L and 4R may be located at the forefront of the electric vehicle 1. Thus, it is possible to prevent the body frame and the body cover from contacting an obstacle such as a step located in front of the vehicle before the front wheels 4L and 4R. First, the front wheels 4L and 4R come into contact with an obstacle in front of the vehicle, so that the obstacle can be easily overcome. For example, even a relatively high step can be overcome.

  According to an embodiment, the rear ends of the rear wheels 5L and 5R may be located at the rearmost position of the electric vehicle 1. Thus, it is possible to prevent the body frame and the body cover from contacting an obstacle such as a step located behind the vehicle before the rear wheels 5L and 5R. When the rear wheels 5L and 5R first contact the obstacle behind the vehicle, the obstacle can be easily overcome. For example, even a relatively high step can be overcome.

  According to some embodiments, at least two electric motors 60L and 60R may be in-wheel motors. There is no need to secure a space for arranging the electric motor and the power transmission mechanism in the body of the vehicle, so that space can be saved. Further, since a drive shaft extending in the left-right direction of the vehicle is not required, the suspension is not restricted by the drive shaft. In addition, by controlling the driving force of each wheel independently using the in-wheel motor, the running performance of the vehicle can be improved.

  According to an embodiment, the rear suspension 50 may be a trailing arm type suspension in which the pivot shaft 56 is located forward of the rotation shaft 105 of the rear wheels 5L and 5R. Thereby, the stroke amount of the rear suspension 50 can be increased. Further, since the suspension arm is not located near the center of the vehicle rear, a space can be secured near the center of the vehicle rear. The space near the center behind the vehicle can be used as, for example, luggage storage. It is possible to realize the electric vehicle 1 with a high traveling property that secures a storage space for luggage.

  According to an embodiment, the height of the pivot shaft 56 when the rear suspension 50 is in the full bump state may be equal to or higher than the height of the rotation shaft 105 of the rear wheels 5L and 5R. Thereby, even when the rear suspension 50 is in the full bump state, the force by which the rear suspension 50 presses the rear wheels 5L and 5R against the road surface can be secured, and the transmission loss of the driving force to the road surface can be reduced.

  According to some embodiments, front suspension 40 may be a double wishbone suspension. As a result, a change in the camber angle when the front wheels 4L and 4R move up and down can be reduced, and a stable grip force of the front wheels 4L and 4R can be secured, and the riding comfort can be improved.

  According to an embodiment, the double wishbone type front suspension 40 may have upper arms 41L and 41R, lower arms 42L and 42R, and shock absorbers 43L and 43R. The shock absorbers 43L and 43R may be attached to the upper arms 41L and 41R. Thus, interference between the knuckle arms 47L and 47R of the steering system and the shock absorbers 43L and 43R can be suppressed. The turning angles of the front wheels 4L and 4R can be increased, and the minimum turning radius of the vehicle can be reduced.

  According to an embodiment, when the front suspension 40 is fully extended, the height of the rotating shaft 104 of the front wheels 4L and 4R is equal to or less than the minimum ground clearance 117 of the electric vehicle 1 and the front suspension 40 is in the full bump state. , The height of the rotating shaft 104 of the front wheels 4L and 4R may be equal to or higher than the height 118 of the upper surface of the footboard 8. When the stroke amount of the front suspension 40 is large, it is easy to maintain a stable vehicle posture when traveling on a road surface with severe unevenness or over a step.

  According to an embodiment, when the rear suspension 50 is in the fully extended state, the height of the rotating shafts 105 of the rear wheels 5L and 5R is equal to or less than the minimum ground clearance 117 of the electric vehicle 1 and the rear suspension 50 is In this state, the height of the rotating shaft 105 of the rear wheels 5L and 5R may be equal to or higher than the height 118 of the upper surface of the footboard 8. When the stroke amount of the rear suspension 50 is large, it is easy to maintain a stable vehicle posture when traveling on a road surface with severe unevenness or over a step.

  According to an embodiment, the electric vehicle 1 may be a handle-type electric wheelchair. As a result, a steering wheel-type electric wheelchair with improved running performance is realized, and the occupant in the steering wheel-type electric wheelchair can have a wider range of action.

  The embodiments of the present invention have been described above. The above description of the embodiments is an exemplification of the present invention, and does not limit the present invention. Further, an embodiment in which the respective components described in the above embodiment are appropriately combined is also possible. The present invention can be modified, replaced, added, omitted, etc. within the scope of the claims or the equivalents thereof.

  INDUSTRIAL APPLICABILITY The present invention is particularly useful in the field of a single-seat electric vehicle such as a handle-type electric wheelchair.

  1: single-seat electric vehicle (handle-type electric wheelchair), 2: body frame, 3: seat, 4L, 4R: front wheel, 5L, 5R: rear wheel, 6: steering wheel, 7: accelerator operator, 8: foot board, 10: Battery, 21: Down tube, 22: Head tube, 23: Front of frame, 24: Bottom of frame, 25: Rear of frame, 26: Steering column, 31L, 31R: Armrest, 32: Backrest, 33: Seat frame, 34: Body cover, 35: Front guard, 36: Front carrier, 40: Front suspension, 41L, 41R: Upper arm, 42L, 42R: Lower arm, 43L, 43R: Shock absorber, 44L, 43R: Shock absorber Upper part, 45L, 45R: lower part of shock absorber, 46L, 46R: tie rod, 47L, 47R: knuckle arm, 48L, 48R: suspension tower, 49: pitman arm, 50: rear suspension, 51L, 51R: trailing arm, 53L, 53R: Shock absorber, 54L, 54R: Upper part of shock absorber, 55L, 55R: Lower part of shock absorber, 56: Pivot shaft, 57: Stabilizer, 60L, 60R: Electric motor (in-wheel motor), 61L, 61R: Motor rotation Sensor, 70: Control unit (MCU), 71: Operation circuit, 72: Memory, 73L, 73R: Motor drive circuit, 81: Steering angle sensor, 91: Front end position of vehicle body, 92: Vehicle body Rear end position, 94: front end position of front wheel, 95: rear end position of rear wheel, 104: rotation axis of front wheel, 105: rotation axis of rear wheel, 107: lowest position of body frame, 108: upper surface of footboard, 115: height of the rotation axis of the rear wheel, 116: height of the center of the pivot axis, 117: minimum ground clearance, 118: height of the footboard upper surface

Claims (13)

A single-seat electric vehicle,
A seat on which the occupant sits,
An armrest on which the occupant places his arm,
A foot board on which the occupant places his feet,
At least four wheels including a front wheel and a rear wheel;
At least two electric motors for driving at least two of the wheels independently of each other,
An independent suspension front suspension that supports the front wheels,
An independent suspension rear suspension that supports the rear wheel,
With
In the state where the occupant is not in the vehicle, the arm of the independently suspended front suspension has a dihedral angle. A handle for the occupant to steer,
A steering column provided on a transmission path for transmitting the operation of the steering wheel by the occupant to the front wheels;
A head tube through which the steering column passes,
A suspension tower for mounting the upper part of the front suspension,
Further comprising
The one-seat electric vehicle according to claim 1, wherein the suspension tower is provided on the head tube.   The one-seater electric vehicle according to claim 1, wherein an upper portion of the rear suspension is attached to the seat.   The single-seat electric vehicle according to any one of claims 1 to 3, wherein a front end of the front wheel is positioned at the forefront of the single-seat electric vehicle.   The single-seat electric vehicle according to any one of claims 1 to 4, wherein a rear end of the rear wheel is located at the rearmost position of the single-seat electric vehicle.   The single-seat electric vehicle according to any one of claims 1 to 5, wherein the at least two electric motors are in-wheel motors.   The single-seat electric vehicle according to any one of claims 1 to 6, wherein the rear suspension is a trailing arm type suspension in which a pivot axis is located forward of a rotation axis of the rear wheel.   The single-seat electric vehicle according to claim 7, wherein a height of the pivot shaft when the rear suspension is in a full bump state is equal to or greater than a height of a rotation shaft of the rear wheel.   The single-seat electric vehicle according to any one of claims 1 to 8, wherein the front suspension is a double wishbone type suspension. The double wishbone suspension has an upper arm, a lower arm, and a shock absorber,
The single-seat electric vehicle according to claim 9, wherein the shock absorber is attached to the upper arm. The height of the rotation axis of the front wheels when the front suspension is fully extended is less than or equal to the minimum ground clearance of the single-seat electric vehicle,
The single-seat electric vehicle according to any one of claims 1 to 10, wherein a height of a rotation axis of the front wheel when the front suspension is in a full bump state is equal to or higher than a height of an upper surface of the footboard. The height of the rotation axis of the rear wheel when the rear suspension is fully extended is less than or equal to the minimum ground clearance of the single-seat electric vehicle,
The single-seat electric vehicle according to any one of claims 1 to 11, wherein a height of a rotation axis of the rear wheel when the rear suspension is in a full bump state is equal to or greater than a height of an upper surface of the footboard.   The single-seat electric vehicle according to any one of claims 1 to 12, wherein the single-seat electric vehicle is a handle-type electric wheelchair.

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