JP2022098037A - Front two-wheel tricycle - Google Patents

Abstract

To provide a front two-wheel tricycle capable of increasing the degree of freedom for design matters relating to front two-wheels upon maintaining the linear traveling performance while enhancing the steering property.SOLUTION: A front two-wheel tricycle 11 includes: a handle shaft body 25 which is supported by a head tube 15a of a frame 15 so as to be freely rotatable around a steering axis line Sx displaced backward as becoming apart from the ground; a seesaw member 27 which is supported by the handle shaft body 25 below the head tube 15a so as to be freely rotatable around an axial line Lx extending forward and downward, and supports, to right and left ends, a right front wheel 12b and a left front wheel 12a, respectively, so as to be freely displaceable in a vertical direction relative to the handle shaft body 25; and a link mechanism 28 which controls respective camber angles of the right front wheel 12b and the left front wheel 12a in accordance with the vertical displacement of the right front wheel 12b and that of the left front wheel 12a.SELECTED DRAWING: Figure 1

Description

The present invention comprises a handle shaft that is rotatably supported by the head tube of the frame around a steering axis that is displaced rearward as it moves away from the ground, and a handle shaft that is rotatably supported by the handle shaft below the head tube that is rotatably around the axis. At the left and right ends, a seesaw member that supports the left front wheel and the right front wheel so that they can be freely displaced in the vertical direction with respect to the handle shaft, and the camber angle of the left front wheel and the right front wheel is controlled according to the vertical displacement of the left front wheel and the right front wheel. It relates to a front two-wheeled three-wheeled vehicle equipped with a link mechanism.

Patent Document 1 discloses a front two-wheel tricycle including front two wheels that function as steering wheels. Below the head tube, a seesaw member is rotatably supported on the handle shaft body around an axis extending upward. The front forks of the left front wheel and the right front wheel are connected to the left and right ends of the seesaw member so as to be vertically displaceable with respect to the handle axle. The link mechanism works to control the camber angles of the left front wheel and the right front wheel according to the vertical displacement of the front fork.

Japanese Unexamined Patent Publication No. 2010-184508 Japanese Unexamined Patent Publication No. 2019-137115

Since the steering axis tilts backward, when the steering wheel axle rotates around the steering axis in response to the turning operation, the inner ring is pressed against the ground according to the steering force due to the influence of the scrub radius. At this time, if the axis of the seesaw member is set to rise forward, the reaction force from the ground is converted into the rotational force of the handle shaft body around the steering axis, so that the reaction force is pushed back to the handle against the operation force of the occupant. Force acts. Steerability deteriorates. Good turning motion is hindered.

An object of the present invention is to provide a front two-wheel tricycle capable of increasing the degree of freedom in design matters relating to the front two wheels in maintaining straightness while improving steerability.

According to one embodiment of the present invention, a handle shaft body rotatably supported by a head tube of a frame around a steering axis that is displaced rearward as it moves away from the ground, and the head tube rotatably around an axis extending downwardly forward. A seesaw member that is supported by the handle axle body below and supports the left front wheel and the right front wheel at the left and right ends so as to be vertically displaceable with respect to the handle axle body, and the left front wheel and the right front wheel in the vertical direction. A front two-wheeled three-wheeled vehicle provided with a link mechanism for controlling the camber angle of the left front wheel and the right front wheel according to the displacement is provided.

When the front two-wheeled tricycle goes straight, a driving force acts backward on the left front wheel and the right front wheel with the axis as a fulcrum according to the frictional force with the ground. In the seesaw member, the rearward driving force of the left front wheel and the rearward driving force of the right front wheel are balanced around the axis. The straightness of the front two-wheeled tricycle can be enhanced by balancing the driving force acting on the left front wheel and the right front wheel around the axis by the action of the seesaw member. Since the steering axis tilts backward, when the steering wheel axle rotates around the steering axis in response to the turning operation, the inner ring is pressed against the ground according to the steering force. Even if the steering force acts in this way, the inner ring can be moved upward from the ground, so that deterioration of steerability can be avoided. The occupant can steer the steering wheel well. Since the inner ring cuts satisfactorily according to the inclination of the frame during turning, good turning performance can be ensured. In particular, since the straightness of the front two-wheeled tricycle is ensured according to the inclination of the axis of the seesaw member, the degree of freedom in the caster angle, trail amount and other design items can be expanded.

As described above, according to the disclosed front two-wheel tricycle, the degree of freedom in design matters related to the front two wheels can be expanded in maintaining straightness while improving steerability.

It is a side view which shows outline the whole structure of the front two-wheeled tricycle which concerns on one Embodiment of this invention. It is a front view of the front two-wheeled tricycle observed from the direction of arrow 2 of FIG. It is a block diagram which shows schematic structure of an electric drive system. It is a flowchart which shows the processing operation of a controller roughly. It is a flowchart which shows the process operation of cruising control roughly. It is a flowchart which shows the process operation of straight-ahead control roughly. It is a flowchart which shows the processing operation of a turning control roughly. It is a flowchart which shows the process operation of the slope running control roughly. It is a flowchart which shows the process operation of the squeeze control roughly.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. In the following description, the front-rear, up-down, and left-right directions refer to the directions seen by the occupants on the front two-wheeled tricycle.

FIG. 1 schematically shows an overall configuration of a front two-wheeled tricycle 11 according to an embodiment of the present invention. The front two-wheel tricycle 11 is connected to the steering system 13 that supports the left front wheel 12a and the right front wheel 12b arranged side by side, and the steering system 13 at the front end, and is rotatably single at a position separated from the front end to the rear. It includes a frame 15 that supports the rear wheels 14. The frame 15 includes a head tube 15a arranged above the left front wheel 12a and the right front wheel 12b, a down tube 15b extending rearward from the head tube 15a, and a seat tube 15c extending upward from the down tube 15b behind the head tube 15a. And a chain stay 15d that extends further rearward from the down tube 15b and rotatably supports the rear wheel 14 around the axis Xr. When the axis Xr of the rear wheel 14 is positioned in the horizontal direction, the self-supporting posture of the frame 15 is ensured. At this time, the left and right center surfaces of the frame 15 coincide with the vertical plane.

A saddle 16 is supported at the upper end of the seat tube 15c. The saddle 16 is fixed to the seat pillar 17 inserted into the seat tube 15c. The saddle 16 receives the buttock of the occupant.

A human-powered drive system 18 that drives the rear wheels 14 around the axis Xr by human power of the occupant is coupled to the frame 15. The human-powered drive system 18 includes a crank 19 rotatably supported by a down tube 15b below the seat tube 15c, a drive sprocket 21 fixed to the crank 19 coaxially with the rotation axis Xc of the crank 19, and a rear wheel 14. A driven sprocket 22 fixed to the rear wheel 14 coaxially with the axis Xr, and a chain 23 wound around the drive sprocket 21 and the driven sprocket 22 are provided. The crank 19 has an axial center parallel to the axis Xr of the rear wheel 14, and is rotatably supported by the bearing of the down tube 15b, and one end of the drive shaft 19a protruding to the left side of the down tube 15b. The left arm 19b, which is coupled to the drive shaft 19a and extends in the centrifugal direction, and the right arm 19c, which is coupled to the other end of the drive shaft 19a that protrudes to the right of the down tube 15b and extends in the centrifugal direction from the drive shaft 19a. Have. The left arm 19b and the right arm 19c are arranged at intervals of 180 degrees around the axis of the drive shaft 19a. A pedal 24 is connected to the tips of the left arm 19b and the right arm 19c, respectively. The pedal 24 is rotatably supported by the left arm 19b and the right arm 19c around a rotation axis parallel to the axis of the drive shaft 19a. The occupant can place his / her left and right feet on the left and right pedals 24 while sitting on the saddle 16.

The steering system 13 has a handle shaft body 25 rotatably connected to the head tube 15a around the steering axis Sx that is displaced rearward as it moves away from the ground, and a left and right handle shaft body 25 connected to the handle shaft body 25 above the head tube 15a. The handle bar 26 extending in the direction and the axis extending downward in the forward direction (hereinafter referred to as "forward downward axis") are rotatably supported by the handle shaft body 25 below the head tube 15a and are supported by the handle shaft body 25 at the left and right ends. The seesaw member 27 that supports the left front wheel 12a and the right front wheel 12b can be freely displaced upward with respect to the vehicle, and the camber angle of the left front wheel 12a and the right front wheel 12b is controlled according to the vertical displacement of the left front wheel 12a and the right front wheel 12b. The link mechanism 28 is provided.

As shown in FIG. 2, grips 31 are fixed to the left and right ends of the handlebar 26, respectively. A rear wheel brake lever 32 is swingably attached to the left end of the handlebar 26. The rear wheel brake lever 32 is connected to the brake of the rear wheel 14, for example, by a wire 33. The rear wheel brake lever 32 extends in parallel with the left grip 31. The left hand of the occupant can operate the rear wheel brake lever 32 while grasping the grip 31.

A front wheel brake lever 34 is swingably attached to the right end of the handlebar 26. The front wheel brake lever 34 is connected to, for example, the brakes of the front wheels 12a and 12b by a wire 35. The front wheel brake lever 34 extends in parallel with the right grip 31. The occupant's right hand can operate the front wheel brake lever 34 while grasping the grip 31.

The link mechanism 28 has a left knuckle 37 connected to the seesaw member 27 on the left side of the front-down axis Lx and a connecting axis parallel to the front-down axis Lx so as to be rotatable around the connection axis Xp parallel to the front-down axis Lx. It has a right knuckle 38 that is rotatably rotated around Xq and is connected to the seesaw member 27 on the right side of the front descending axis Lx, and a link arm 39 that connects the left knuckle 37 and the right knuckle 38 to each other. The link arm 39 is swingably connected to the left knuckle 37 and the right knuckle 38, respectively, around the swing axis parallel to the connecting axes Xp and Xq. Thus, a quadrilateral linkage 28 with four joints is established. The link arm 39 is rotatably coupled to the handle shaft body 25 around the auxiliary axis Xa extending parallel to the front descending axis Lx in the vertical plane including the front descending axis Lx. The camber angle of the left front wheel 12a and the right front wheel 12b can be controlled by the action of the link arm 39 according to the vertical displacement of the left front wheel 12a and the right front wheel 12b.

The hub 41 of the left front wheel 12a is rotatably coupled to the left knuckle 37 around the rotation axis XL. The hub 41 of the right front wheel 12b is coupled to the right knuckle 38 so as to be rotatable around the rotation axis XR. As shown in FIG. 1, the left front wheel 12a, the right front wheel 12b, and the rear wheel 14 are attached to the hub 41, the rim 43 coaxial with the hub 41 and connected to the hub 41 by the spokes 42, and the rim 43, respectively. It is formed of a rubber tire 44 to be mounted.

As shown in FIG. 3, the front two-wheel tricycle 11 is coupled with an electric drive system 51 that drives the left front wheel 12a and the right front wheel 12b around the rotation axis XL and XR by the driving force generated by electric power. The electric drive system 51 is connected to a first electric motor 52 that is connected to the left front wheel 12a and applies a driving force to the left front wheel 12a according to the supply of electric power, and is connected to the first electric motor 52 and is supplied to the first electric motor 52. It is connected to a first driver circuit 53 that controls the electric power to be generated, a second electric motor 54 that is connected to the right front wheel 12b and applies a driving force to the right front wheel 12b according to the supply of electric power, and a second electric motor 54. , A second driver circuit 55 that controls the electric power supplied to the second motor 54, is connected to the first driver circuit 53 and the second driver circuit 55, and is supplied to the first driver circuit 53 and the second driver circuit 55. It is equipped with a battery 56 for storing electric power. For example, a direct current (DC) brushless motor can be used for the first electric motor 52 and the second electric motor 54. The first motor 52 and the second motor 54 may be directly connected to the axles of the left front wheel 12a and the right front wheel 12b, or may be indirectly connected via a gear mechanism. Electric power is individually supplied from the battery 56 to the first electric motor 52 and the second electric motor 54. Therefore, the driving force of the left front wheel 12a and the right front wheel 12b is set individually.

The electric drive system 51 is further connected to the first driver circuit 53 and the second driver circuit 55 to control the operation of the first driver circuit 53 and the second driver circuit 55, and the rotational speed of the left front wheel 12a. The left front wheel speed sensor 58 that detects and supplies the detected left front wheel speed to the controller 57, and the right front wheel speed sensor 59 that detects the rotational speed of the right front wheel 12b and supplies the detected right front wheel speed to the controller 57. The vehicle speed is detected based on the rotational speed of the rear wheels 14, and the detected vehicle speed is supplied to the controller 57. The rear wheel speed sensor 61 detects the pedaling force acting on the crank 19, and supplies the magnitude of the detected pedaling force to the controller 57. The pedaling force sensor 62, the steering sensor 63 that detects the steering angle of the handle bar 26 with respect to the head tube 15a and supplies the detected steering angle to the controller 57, and the tilt angle of the seat tube 15c with respect to the vertical direction (gravity direction). Is detected and the detected tilt angle is supplied to the controller 57. The tilt sensor 64 detects the tilt angle of the road surface in the left-right direction with respect to the horizontal plane orthogonal to the vertical direction, and supplies the detected tilt angle to the controller 57. The slope sensor 65 is provided.

The rear wheel speed sensor 61 is attached to the bearing of the rear wheel 14, for example, and outputs an electric signal for specifying the vehicle speed based on the rotation speed of the rear wheel 14. The steering sensor 63 is attached to the head tube 15a, for example, and outputs an electric signal for specifying the rotation angle of the steering wheel shaft body 25 around the steering axis Sx. The tilt sensor 64 is attached to the seat tube 15c, for example, and outputs an electric signal for specifying the tilt angle in the left-right direction with respect to the vertical plane orthogonal to the axis Xr of the rear wheel 14 when traveling straight on a flat ground. For example, a gyro sensor can be used for the tilt sensor 64. The slope sensor 65 is attached to the handle shaft body 25, for example, and outputs an electric signal for specifying the tilt angle of the link mechanism 28 around the front-down axis Lx of the seesaw member 27. Operating power is supplied from the battery 56 to the controller 57, the speed sensors 58, 59, 61, the pedal force sensor 62, the steering sensor 63, the tilt sensor 64, and the slope sensor 65.

The controller 57 includes a storage device 57a. The storage device 57a stores, for example, a look-up table that allocates the rotation speed (per minute) of the electric motor to the pedal effort. In the look-up table, the current value that realizes the assigned rotation speed (per minute) is specified for each magnitude of the pedaling force.

In traveling, the occupant straddles the saddle 16 of the self-supporting front two-wheeled tricycle 11. The occupant holds the left grip 31 with his left hand and the right grip 31 with his right hand. The occupant puts his left foot and right foot on the left and right pedals 24, respectively. When the occupant steps on the pedal 24, the occupant's pedaling force acts on the crank 19. The crank 19 rotates around the rotation axis Xc. The rotation of the crank 19 is transmitted to the rear wheels 14 by the action of the drive sprocket 21, the chain 23 and the driven sprocket 22. In this way, the driving force of human power causes the rotation of the rear wheel 14. The front two-wheeled tricycle 11 moves forward.

When the switch of the controller 57 is turned on, the controller 57 controls the electric assist. As shown in FIG. 4, the controller 57 detects the traveling speed in step S1 during traveling. Upon detection, a signal is supplied to the controller 57 from the rear wheel speed sensor 61. When it is determined that the traveling speed exceeds a predetermined speed, the controller 57 performs cruising control in step S2. When the speed exceeds a predetermined speed, the posture and behavior of the front two-wheeled tricycle 11 are stabilized by the action of the inertial force in the forward direction. Therefore, the controller 57 controls the driving of the left front wheel 12a and the right front wheel 12b based on a stable posture and behavior. Details of cruising control will be described later.

If the traveling speed is equal to or lower than the predetermined speed in step S1, the controller 57 performs the sawing control in step S3. Since the posture and behavior of the front two-wheeled tricycle 11 are not stable at the time of sawing out, the drive of the left front wheel 12a and the right front wheel 12b is controlled based on the instability of the posture and behavior. The details of the sawing control will be described later.

As shown in FIG. 5, in cruising control, the controller 57 detects the inclination angle of the seat tube 15c in the left-right direction with respect to the vertical plane orthogonal to the axis Xr of the rear wheel 14 when traveling straight on a flat ground in step T1. Upon detection, a signal is supplied to the controller 57 from the tilt sensor 64. If the inclination of the seat tube 15c is equal to or less than a predetermined inclination angle, the controller 57 performs straight-ahead control in step T2. When the inclination of the seat tube 15c is equal to or less than a predetermined inclination angle, it is presumed that the occupant intends to travel straight. The controller 57 controls the drive of the left front wheel 12a and the right front wheel 12b to improve the straight-line stability of the front two-wheel tricycle 11. The details of the straight-ahead control will be described later.

When it is determined in step T1 that the inclination of the seat tube 15c exceeds a predetermined inclination angle, the controller 57 performs rotation control in step T3. When the inclination of the seat tube 15c exceeds a predetermined inclination angle, it is presumed that the occupant intends to turn. Generally, the occupant leans in the turning direction to move the center of gravity. Therefore, the controller 57 controls the drive of the left front wheel 12a and the right front wheel 12b based on the difference in the number of rotations generated during turning between the left front wheel 12a and the right front wheel 12b. In this way, the stability of the behavior is enhanced when turning.
The details of the turning control will be described later.

As shown in FIG. 6, when the straight-ahead control is executed, the controller 57 detects the steering angle of the handlebar 26 in step V1. Upon detection, a signal is supplied to the controller 57 from the steering sensor 63. When it is determined that the left front wheel 12a is the inner wheel based on the steering angle, in step V2, the controller 57 generates a control signal for applying a large driving force to the left front wheel 12a as compared with the driving force of the right front wheel 12b. In generating the control signal, the current value supplied to the first electric motor 52 is acquired from the look-up table according to the magnitude of the pedaling force. The current value supplied to the second electric motor 54 is specified by multiplying the acquired current value by the coefficient (<1). The larger the tilt angle (or steering angle), the smaller the coefficient.

In the subsequent step V3, the control signal is supplied to the first driver circuit 53 and the second driver circuit 55. The first driver circuit 53 supplies a current to the first motor 52 at a current value designated based on the control signal. The first electric motor 52 drives the left front wheel 12a. The second driver circuit 55 supplies a current to the second motor 54 at a current value designated based on the control signal. The second electric motor 54 drives the left front wheel 12a. Even if the handlebar 26 is turned to the left at a minute angle, the handlebar 26 is returned in the straight direction by applying a larger driving force to the left front wheel 12a (inner ring) as compared with the right front wheel 12b (outer ring).

When it is determined in step V1 that the right front wheel 12b is an inner wheel based on the steering angle, in step V4, the controller 57 generates a control signal that applies a large driving force to the right front wheel 12b as compared with the driving force of the left front wheel 12a. do. In generating the control signal, the current value supplied to the second electric motor 54 is acquired from the look-up table according to the magnitude of the pedaling force. The current value supplied to the first electric motor 52 is specified by multiplying the acquired current value by the coefficient (<1).

In the subsequent step V3, the control signal is supplied to the first driver circuit 53 and the second driver circuit 55. The first driver circuit 53 supplies a current to the first motor 52 at a current value designated based on the control signal. The first electric motor 52 drives the left front wheel 12a. The second driver circuit 55 supplies a current to the second motor 54 at a current value designated based on the control signal. The second electric motor 54 drives the left front wheel 12a. Even if the handlebar 26 is turned to the right at a minute angle, the handlebar 26 is returned in the straight direction by applying a large driving force to the right front wheel 12b (inner ring) as compared with the left front wheel 12a (outer ring).

As described above, when the inclination of the seat tube 15c is equal to or less than a predetermined value, it is presumed that the occupant intends to travel straight. At this time, when the steering of the handlebar 26 is detected, a larger driving force is applied to the inner ring as compared with the outer ring, so that the handlebar 26 is returned in the straight direction. In this way, straight-line stability is enhanced. Generally, when traveling straight, the occupant of the two-wheeled vehicle compensates for the deviation of the center of gravity in the left-right direction by steering the steering wheel. The steering of the handlebar 26 is supported by the actions of the first electric motor 52 and the second electric motor 54, so that the straight running stability is enhanced. The stability of the behavior during running is enhanced.

As shown in FIG. 7, when the turning control is executed, the controller 57 detects the steering angle of the handlebar 26 in step W1. Upon detection, a signal is supplied to the controller 57 from the steering sensor 63. When it is determined that the left front wheel 12a is the inner wheel based on the steering angle, in step W2, the controller 57 generates a control signal for applying a large driving force to the right front wheel 12b as compared with the driving force of the left front wheel 12a. In generating the control signal, the current value supplied to the second electric motor 54 is acquired from the look-up table according to the magnitude of the pedaling force. The current value supplied to the first electric motor 52 is specified by multiplying the acquired current value by the coefficient (<1). The larger the tilt angle (or steering angle), the smaller the coefficient.

In the subsequent step W3, the control signal is supplied to the first driver circuit 53 and the second driver circuit 55. The first driver circuit 53 supplies a current to the first motor 52 at a current value designated based on the control signal. The first electric motor 52 drives the left front wheel 12a. The second driver circuit 55 supplies a current to the second motor 54 at a current value designated based on the control signal. The second electric motor 54 drives the left front wheel 12a. By applying a larger driving force to the right front wheel 12b (outer ring) than to the left front wheel 12a (inner ring), a difference in rotation speed is intentionally generated between the inner ring and the outer ring during turning.

When it is determined in step W1 that the left front wheel 12a is the outer wheel based on the steering angle, in step W4, the controller 57 generates a control signal that applies a large driving force to the left front wheel 12a as compared with the driving force of the right front wheel 12b. do. In generating the control signal, the current value supplied to the first electric motor 52 is acquired from the look-up table according to the magnitude of the pedaling force. The current value supplied to the second electric motor 54 is specified by multiplying the acquired current value by the coefficient (<1).

In the subsequent step W3, the control signal is supplied to the first driver circuit 53 and the second driver circuit 55. The first driver circuit 53 supplies a current to the first motor 52 at a current value designated based on the control signal. The first electric motor 52 drives the left front wheel 12a. The second driver circuit 55 supplies a current to the second motor 54 at a current value designated based on the control signal. The second electric motor 54 drives the left front wheel 12a. By applying a larger driving force to the left front wheel 12a (outer ring) than to the right front wheel 12b (inner ring), a difference in rotation speed is intentionally generated between the inner ring and the outer ring during turning.

As described above, when the inclination of the seat tube 15c exceeds a predetermined value, it is presumed that the occupant intends to turn. Generally, the occupant leans in the turning direction to move the center of gravity. At this time, when the steering angle of the handlebar 26 is detected, a larger driving force is applied to the outer ring as compared with the inner ring, so that a difference in rotation speed is intentionally generated between the inner ring and the outer ring during turning. can. The vehicle can turn smoothly. The stability of behavior can be enhanced when turning. Good steerability can be achieved. By switching the magnitude relationship of the driving force between the inner ring and the outer ring during straight running and turning, the stability of the behavior during running can be satisfactorily improved.

Here, in general, the occupant leans his / her body in the turning direction to move the center of gravity. The greater the curvature of the turn, the greater the distance the center of gravity moves. As the moving distance of the center of gravity increases, the inclination of the seat tube 15c increases. Therefore, if the driving force difference between the inner ring and the outer ring becomes large according to the inclination of the seat tube 15c, the vehicle can turn smoothly according to the curvature of turning. The stability of behavior can be enhanced when turning. The stability of the behavior during running can be enhanced.

In the cruising control, the slope traveling control may be executed in an overlapping manner at the time of straight-ahead control. As shown in FIG. 8, when the slope traveling control is executed, the controller 57 detects the inclination angle of the road surface in step Q1. Upon detection, a signal is supplied to the controller 57 from the slope sensor 65. When it is determined that the left front wheel 12a is the lower wheel based on the inclination angle of the road surface, the controller 57 generates a control signal in step Q2 to apply a larger driving force to the left front wheel 12a than the driving force of the right front wheel 12b. do. In generating the control signal, the current value supplied to the first electric motor 52 is acquired from the look-up table according to the magnitude of the pedaling force. The current value supplied to the second electric motor 54 is specified by multiplying the acquired current value by the coefficient (<1). The larger the tilt angle, the smaller the coefficient.

In the following step Q3, the control signal is supplied to the first driver circuit 53 and the second driver circuit 55. The first driver circuit 53 supplies a current to the first motor 52 at a current value designated based on the control signal. The first electric motor 52 drives the left front wheel 12a. The second driver circuit 55 supplies a current to the second motor 54 at a current value designated based on the control signal. The second electric motor 54 drives the left front wheel 12b. When traveling on a slope that slopes in the left-right direction, a larger driving force is applied to the left front wheel 12a (lower wheel) than to the right front wheel 12b (upper wheel), so that the drive resists the downward force along the slope. Force is applied to the left front wheel 12a and the right front wheel 12b. In this way, straight-line stability is enhanced. The stability of the behavior during running can be enhanced.

When it is determined in step Q1 that the right front wheel 12b is the lower wheel based on the inclination angle of the road surface, the controller 57 applies a larger driving force to the right front wheel 12b than the driving force of the left front wheel 12a in step Q4. Generate a control signal. In generating the control signal, the current value supplied to the second electric motor 54 is acquired from the look-up table according to the magnitude of the pedaling force. The current value supplied to the first electric motor 52 is specified by multiplying the acquired current value by the coefficient (<1).

In the following step Q3, the control signal is supplied to the first driver circuit 53 and the second driver circuit 55. The first driver circuit 53 supplies a current to the first motor 52 at a current value designated based on the control signal. The first electric motor 52 drives the left front wheel 12a. The second driver circuit 55 supplies a current to the second motor 54 at a current value designated based on the control signal. The second electric motor 54 drives the left front wheel 12b. When traveling on a slope that slopes in the left-right direction, a larger driving force is applied to the right front wheel 12b (lower wheel) than to the left front wheel 12a (upper wheel), so that the drive resists the downward force along the slope. Force is applied to the left front wheel 12a and the right front wheel 12b. In this way, straight-line stability is enhanced. The stability of the behavior during running can be enhanced.

As shown in FIG. 9, when the sawing control is executed, the controller 57 detects the rotation speed of the left front wheel 12a and the rotation speed of the right front wheel 12b in step R1. Upon detection, signals are supplied to the controller 57 from the left front wheel speed sensor 58 and the right front wheel speed sensor 59. If the rotation speed of the left front wheel 12a is smaller than the rotation speed of the right front wheel 12b, the controller 57 generates a control signal based on the rotation speed of the left front wheel 12a in step R2. In the control signal, the current value commonly supplied to the first electric motor 52 and the second electric motor 54 is specified according to the magnitude of the pedaling force (human power).

In the subsequent step R3, the control signal is supplied to the first driver circuit 53 and the second driver circuit 55. The first driver circuit 53 supplies a current to the first motor 52 at a current value designated based on the control signal. The first electric motor 52 drives the left front wheel 12a. The second driver circuit 55 supplies a current to the second motor 54 at a current value designated based on the control signal. The second electric motor 54 drives the left front wheel 12b.

If the rotation speed of the left front wheel 12a is equal to or higher than the rotation speed of the right front wheel 12b, the controller 57 generates a control signal based on the rotation speed of the right front wheel 12b in step R4. In the control signal, the current value commonly supplied to the first electric motor 52 and the second electric motor 54 is specified according to the magnitude of the pedaling force (human power).

In the subsequent step R3, the control signal is supplied to the first driver circuit 53 and the second driver circuit 55. The first driver circuit 53 supplies a current to the first motor 52 at a current value designated based on the control signal. The first electric motor 52 drives the left front wheel 12a. The second driver circuit 55 supplies a current to the second motor 54 at a current value designated based on the control signal. The second electric motor 54 drives the left front wheel 12b.

Since the inertial force is not sufficiently increased in the forward direction when starting to squeeze out from a stationary state, the center of gravity shifts in the left-right direction, and a force that sways in the left-right direction acts on the front two-wheel tricycle 11. At this time, even if the first electric motor 52 and the second electric motor 54 are individually controlled according to the inclination of the seat tube 15c, such control does not contribute to the stabilization of the posture. Power is wasted. When one rotation speed is set in common for the left front wheel 12a and the right front wheel 12b, waste of control can be eliminated and power consumption can be suppressed.

In the present embodiment, the frame 15 supports the left front wheel 12a and the right front wheel 12b so as to be individually displaceable in the vertical direction. The left front wheel 12a and the right front wheel 12b can be individually displaced in the vertical direction of the vehicle body according to the reaction force from the ground. Displacement of the left front wheel 12a or the right front wheel 12b can be caused by the difference in the driving force of the left front wheel 12a and the right front wheel 12b. In this way, the posture of the vehicle body can be further stabilized.

The frame 15 according to the present embodiment has a first virtual vertical surface Vf that is orthogonal to the axis Xff when traveling straight on flat ground and passes through a ground contact point between the left front wheel 12a and the ground, and a right front wheel that is orthogonal to the axis Xfs when traveling straight on flat ground. It has a structure that allows the center of gravity of the occupant to move outward from the space sandwiched between the second virtual vertical plane Vs passing through the ground contact point between 12b and the ground. Since the distance between the left front wheel 12a and the right front wheel 12b is narrowed with respect to the range of movement of the center of gravity of the occupant, the front two-wheel tricycle 11 can secure a design similar to that of a general two-wheeled bicycle. In this way, the design of the front two-wheeled tricycle 11 can be enhanced.

11 ... front two-wheel tricycle, 12a ... left front wheel, 12b ... right front wheel, 15 ... frame, 15a ... head tube, 25 ... handle axle, 27 ... seesaw member, 28 ... link mechanism, Lx ... front-down axis, Sx … Steering axis.

Claims (1)

A steering wheel axle that is rotatably supported by the frame's head tube around a steering axis that displaces backwards as it moves away from the ground.
A seesaw that is rotatably supported by the handle shaft under the head tube and supports the left front wheel and the right front wheel at the left and right ends so as to be vertically displaceable with respect to the handle shaft. Members and
A link mechanism that controls the camber angle of the left front wheel and the right front wheel according to the vertical displacement of the left front wheel and the right front wheel.
A front two-wheeled tricycle characterized by being equipped with.

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