JP6684417B2 - vehicle - Google Patents

Description

  The present invention includes a pair of left and right front wheels and at least one rear wheel, and steers each front wheel by rotating the front wheel support member relative to the vehicle body due to the difference in driving force between the pair of left and right front wheels. It concerns a vehicle that is intended to be performed.

The conventional vehicle disclosed in Patent Document 1 is configured to steer each front wheel by rotating a front wheel support member around a steering axis due to a difference in driving force between a pair of left and right front wheels. The vehicle is steered by steering each front wheel.
Further, in the conventional vehicle disclosed in Patent Document 2, the caster housing supporting the rear wheels is rotated around the rear wheel steering axis by the yaw moment generated by the difference in the driving force between the pair of left and right front wheels. It is configured to be steered by. The biasing force of the coil spring is constantly applied so as to resist the rotation around the rear wheel turning axis of the caster housing, and the biasing force is configured to increase as the traveling speed increases.

Japanese Patent No. 5757511 Japanese Patent No. 6003712

However, in the conventional vehicle disclosed in Patent Document 1, the rotation angle of the front wheel support member around the steered shaft is limited to a certain range in order to avoid interference between the front wheel support member and the vehicle body. It has not been possible to reduce the turning radius when the vehicle turns.
Further, in the conventional vehicle disclosed in Patent Document 2, since the biasing force of the coil spring is constantly applied so as to resist the rotation of the caster housing around the rear wheel steering axis, the driving force between the front wheels is increased. Due to the difference, it was not possible to smoothly rotate the caster housing around the rear wheel steering shaft. Therefore, the responsiveness at the time of steering the rear wheels due to the yaw moment due to the difference in the driving force between the front wheels is poor.

  The present invention has been made to solve such a problem, and can smoothly steer the front wheels and the rear wheels due to the difference in driving force between the pair of left and right front wheels, and has a relatively small turning radius. An object of the present invention is to provide a vehicle that can be driven by.

In order to achieve this object, a vehicle according to the present invention includes a pair of left and right front wheels, at least one rear wheel, a front wheel support member that rotatably supports each of the front wheels, and a front wheel support member. A vehicle body that rotatably supports about the axis of the vehicle and rotatably supports the rear wheels, and a driving force applying unit that individually applies a driving force to each of the front wheels. Steering force for rotating the front wheel support member with respect to the vehicle body around the first axis due to the difference in driving force between the front wheels generated by individually applying the driving force by the driving force applying means. In the vehicle in which each of the front wheels is steered by rotating the front wheel support member around the first axis with respect to the vehicle body, the steering force is resisted against the steering force. Steering resistance imparting means for imparting resistance Further comprising a control means for controlling the driving force applying means and the steering resistance applying means, wherein the rear wheel is in a rolling direction in all horizontal directions or within a specified angle range in the horizontal direction. Is configured to be freely changeable, and the control means is configured to control the turning resistance applying means so as to adjust the resistance according to the driving situation of the vehicle, and the vehicle travels at high speed. The steering resistance applying means is controlled so that the resistance becomes larger when the vehicle is traveling at a lower speed than when the vehicle is running .

A vehicle according to a second aspect of the present invention is the vehicle according to the first aspect , wherein the control means temporarily increases the resistance force when the front wheels are steered. While controlling the applying means, the driving force applied to each of the front wheels is controlled so that the front wheel on the outer side in the steering direction becomes smaller than the front wheel on the inner side in the steering direction, and subsequently, , The steering resistance applying means is controlled so that the resistance becomes smaller, and the driving force applied to each of the front wheels becomes larger at the front wheels on the outside in the steering direction than at the front wheels on the inside in the steering direction. As described above, the driving force applying means is controlled.

A vehicle according to a third aspect of the present invention is the vehicle according to the first or second aspect , wherein the rear wheel is a single rear wheel, and the rear wheel support member rotatably supports the rear wheel. Further, the rear wheel support member is rotatably supported on the vehicle body about a second axis, and the first axis and the second axis each have an upper part forward of a lower part. The second axis is inclined so as to be located, and the intersection of the virtual straight line extending downward and the traveling road surface when the vehicle is moving forward is the traveling road surface of the rear wheel. It is arranged so as to be located in front of the ground contact point in the rolling direction of the rear wheel.

A vehicle according to a fourth aspect of the present invention is the vehicle according to the third aspect , further comprising rolling direction range changing means capable of changing a range of rolling directions in which the rear wheels can be directed, and the control means. The rolling direction range changing means is controlled by the above.

A vehicle according to a fifth aspect of the present invention is the vehicle according to the fourth aspect , wherein the control means rolls the rear wheel when the vehicle travels at a higher speed than when the vehicle travels at a low speed. It is characterized in that the rolling direction range changing means is controlled so that the range of the direction becomes narrow.

  According to the first aspect of the invention, the rear wheels are configured so that the rolling direction can be freely changed, and the resistance force against the steering force for steering the front wheels is adjusted according to the driving situation of the vehicle. Is configured to. Therefore, by appropriately controlling the driving force applied to each front wheel and the resistance force that resists the steering force of the front wheels, it is possible to suitably control the steering of the front wheels and the rear wheels according to the driving situation of the vehicle. it can. Further, since the rolling direction of the rear wheels can be freely changed, the responsiveness at the time of steering the rear wheels by the yaw moment due to the difference in the driving forces of the front wheels becomes good.

Specifically, when the vehicle travels at a low speed, the resistance force against the steered force of the front wheels is controlled to be larger when the vehicle travels at a lower speed. The rear wheel can be smoothly steered by the yaw moment due to the difference in the driving force. Therefore, the vehicle can be turned with a relatively small turning radius, and a small turn can be made even in a narrow place.
On the other hand, when the vehicle travels at high speed, the resistance against the steering force of the front wheels is controlled to be smaller than when traveling at low speed, so the yaw moment due to the difference in driving force between the front wheels is It acts so as to rotate the front wheel support member around the first axis with respect to the vehicle body. For this reason, steering by the rear wheels can be suppressed, and steering is mainly performed by the front wheels, so that high-speed turning performance can be secured.

According to the invention described in claim 2 , when the vehicle is turned, the resistance force against the steering force of the front wheels and the driving force applied to each front wheel are appropriately controlled in two steps. There is. Therefore, the restoring force that causes the front wheel support member and the front wheel, which have been temporarily elastically deformed by the control in the first stage, to return to the original state, is changed by the front wheel and the front wheel support member during the control in the second stage. It can be used as a force to rotate relative to the vehicle body. Therefore, not only can the front wheels be steered by that much, but there is no need to provide a special device for assisting the steering of the front wheels.

According to the third aspect of the present invention, the first axis, which is the center of rotation of the front wheel support member, is inclined so that the upper portion is located in front of the lower portion. When the vehicle turns, the vehicle body tilts inward in the turning direction, and accordingly, the second shaft core, which is the turning center of the rear wheel support member, also tilts. The second axis is inclined so that the upper portion is located in front of the lower portion, and the intersection of the extended virtual straight line and the traveling road surface is located in front of the rear wheel grounding point in the rolling direction of the rear wheel. There is. Therefore, when the vehicle body leans, the reaction force of the rear wheels in the vertical direction from the traveling road surface at the ground contact point causes the rear wheel support member to rotate around the second axis through the rear wheels, and It acts so that the front side of the rolling direction of the wheels is directed in the direction of inclination of the vehicle body. As a result, the rear wheels do not excessively point in the direction opposite to the inclination direction, so that the vehicle can stably turn.

According to the fourth aspect of the invention, the rolling direction range changing means for changing the range of the rolling direction in which the rear wheel can be directed is further provided. By regulating the rolling direction, it is possible to prevent the rear wheel from undesirably largely turning around the second axis. Further, since the rolling direction range changing means changes the rolling direction range of the rear wheels, the rolling direction range of the rear wheels can be freely changed within the range, so that the rolling direction range can be changed. By providing the changing means, the responsiveness at the time of steering the rear wheels is not impaired by the yaw moment due to the difference in the driving force of each front wheel.

According to the invention of claim 5 , when the vehicle travels at high speed, the range of the rolling direction of the rear wheels is controlled to be narrower when the vehicle travels at low speed. By controlling the rolling direction of the rear wheels within a narrow angle range that includes the rear wheels, the rear wheels may not rotate around the second shaft center due to the effects of external wind disturbances and undulations on the road surface when the vehicle is traveling at high speed. It is possible to prevent a desired large rotation.
On the other hand, when traveling at low speed, the range of the rolling direction of the rear wheels is controlled to be wider than when traveling at high speed, and the steering range of the rear wheels is widened accordingly. It is possible to improve the sex.

FIG. 1 is an overall vehicle view showing a state of a vehicle according to an embodiment of the present invention as seen from diagonally above the front. FIG. 3 is an external view showing the same vehicle as seen from the left side. FIG. 3 is an external view showing the vehicle as viewed from above. FIG. 3 is an external view of the vehicle as viewed from the front. FIG. 3 is a block diagram showing a schematic configuration of a control device mounted on the vehicle and various devices related to the control device. FIG. 3 is a vertical cross-sectional view showing the resistance imparting device assembled to the vehicle in a cutaway manner. FIG. 6 is a view showing a state in which a midway portion in the longitudinal direction of the resistance imparting device is broken and viewed from diagonally above.

FIG. 4 is a schematic diagram for explaining the behavior of the vehicle when the vehicle is turning at a low speed. FIG. 3 is an external view showing a state in which the vehicle, which is turning at a low speed, is viewed from above. FIG. 3 is an external view showing a state in which the vehicle, which is turning at a low speed, is viewed from the front. FIG. 6 is a schematic diagram for explaining the behavior of the vehicle when turning at high speed. FIG. 3 is an external view showing a state in which the vehicle that is turning at high speed is viewed from the front. It is a graph which shows the relationship between the magnitude | size of the resistance force of a resistance force application device, and the steering amount of a front wheel side and a rear wheel side.

6 is a graph showing how the steered amounts on the front wheel side and the rear wheel side change when the difference in driving force applied to each front wheel and the resistance force of the resistance force applying device are changed. FIG. 3 is a vertical cross-sectional view showing a broken rotation angle restricting device assembled to the vehicle. It is the figure which showed the state which removed the cover and looked at the same rotation angle control apparatus from diagonally upward. It is a figure which shows the 1st modification which changed control of the vehicle which concerns on embodiment of this invention, and is a schematic diagram for demonstrating a behavior when a vehicle turns at high speed. It is a figure which shows the 2nd modification which changed the control of the vehicle which concerns on embodiment of this invention, and is a schematic diagram for demonstrating a behavior when a vehicle turns at high speed.

It is an external view which shows the state which looked at the place where the vehicle which concerns on a 2nd modification turns at high speed from above. It is a figure which shows the 3rd modification which changed control of the vehicle which concerns on embodiment of this invention, Comprising: When a vehicle turns at high speed, the difference of the driving force given to each front wheel, and a resistance force provision apparatus. 6 is a graph showing how the turning amount on the front wheel side changes when the resistance force of the vehicle changes with two-step control. FIG. 11 is a vertical cross-sectional view showing a resistance force applying device according to a fourth modified example, which has a configuration different from that of the vehicle resistance force applying device according to the embodiment of the present invention. FIG. 9 is an overall vehicle view showing a state of a vehicle according to a fifth modified example in which the rear wheel of the vehicle according to the embodiment of the present invention and the mounting structure thereof are changed, as seen from diagonally above the front.

  Hereinafter, an example of a vehicle according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 16. 1 to FIG. 4, FIG. 9, FIG. 10, and FIG. 12, reference numeral 1 is a vehicle according to the embodiment of the present invention. The direction indicated by the arrow F in FIGS. 1 to 3 and 9 indicates the front of the vehicle 1. In the following description, the terms “front / rear”, “left / right”, “up / down” and “inside / outside” are used to indicate directions and parts with respect to the vehicle 1 and its constituent members. In the state, it refers to the direction and position when the vehicle 1 is seen. The front portion of the vehicle 1 is provided with a pair of left and right front wheels 3, 3, each front wheel 3 is rotatably supported by a front wheel support member 5, and the front wheel support member 5 is swingably supported by a vehicle body frame 7. . A single rear wheel 9 is rotatably supported by the vehicle body frame 7 at the rear portion of the vehicle 1 via a rear wheel support member 11. The vehicle body frame 7 constitutes the "vehicle body" according to the present invention.

  The vehicle body frame 7 includes a frame body 13 having a circular tubular shape extending in the front-rear direction at the center of the vehicle 1 in the left-right direction, a semicircular step 15 connected to an intermediate portion of the frame body 13 in the front-rear direction, A circular tubular shaft support member 17 connected to the front end, a handle post 19 connected to the frame body 13 near the rear of the shaft support member 17 and extending obliquely rearward and upward, and a rear end of the frame body 13 And a cylindrical tubular shaft support member 21 that is bonded. A central portion of the frame body 13 in the front-rear direction is bent downward, and the step 15 is bonded to the bent portion. The frame main body 13 is disposed and bound to the central portion of the step 15 in the left-right direction at the notched portions of the front end portion and the rear end portion thereof. The frame main body 13 extends obliquely upward to the front and obliquely upward to the rear from the recessed portions of the front end and the rear end of the step 15. An intermediate portion in the front-rear direction of the frame main body 13, which is bent downward to be convex, is positioned below the step 15.

  The center portion of the front wheel support member 5 in the left-right direction is disposed in the shaft support member 17, and the front wheel steering shaft 23 (see FIG. 2) is integrally connected to the shaft support member 17 so as to steer the front wheel. It is supported by the shaft support member 17 so as to be rotatable around the axis Lf of the shaft 23. The shaft core Lf is inclined so that its upper portion is located more forward than its lower portion. The shaft core Lf constitutes the “first shaft core” in the present invention. The lower parts of the pair of left and right motor housings 27, 27 are supported by the left and right ends of the front wheel support member 5 so as to be rotatable about the axis Lc of the camber shaft 25 via the camber shaft 25. The shaft core Lc is arranged so as to incline so that its front portion is located below the rear portion and extend in the front-rear direction. Inside each motor housing 27, an electric motor 29 (see FIG. 5) for individually applying a driving force to each front wheel 3 is arranged. Each front wheel 3 has a so-called wheel-in motor structure. The electric motor 29 constitutes “driving force applying means” in the present invention. The rotating shafts of the electric motors 29 are respectively connected to the hubs (not shown) of the front wheels 3, and the rotating shafts of the electric motors 29 rotate so that the front wheels 3 rotate.

  The front wheel support member 5 is rotated about the axis Lf with respect to the vehicle body frame 7 due to the difference in the driving force between the front wheels 3 generated by individually applying the driving force to the front wheels 3 by the electric motor 29. Steering force is generated. The front wheel support member 5 is configured to steer each front wheel 3 by rotating the front wheel support member 5 around the axis Lf with respect to the vehicle body frame 7. The driving force applied to each front wheel 3 when a difference in driving force between the front wheels 3 is generated includes a driving force that drives the front wheels 3 in the same direction as the traveling direction of the vehicle 1 and a driving force of the vehicle 1. The driving force for driving the front wheels 3 in the direction opposite to the traveling direction is included, and the driving force for driving the front wheels 3 in the opposite direction includes the regenerative braking force described later. When a difference in driving force is generated between the front wheels 3, different driving forces are applied to the front wheels 3 in the same direction, and when driving forces having the same or different magnitudes are applied in opposite directions. In some cases, the driving force may be applied to the front wheels 3.

  A pair of left and right rod-shaped camber link members 31 arranged so as to extend in the left-right direction are provided at a portion of the frame body 13 located between the portion where the handle post 19 is attached and the portion where the step 15 is attached. , 31 are rotatably connected via ball joints or rubber bushes, respectively, and the other end of each camber link member 31 is rotatably connected to the upper portion of each motor housing 27 via a ball joint. It is connected.

On the other hand, in the rear wheel support member 11, a rear wheel steering shaft 11a (see FIG. 2) provided at an upper end portion thereof is inserted into the shaft support member 21, and the rear wheel steering shaft 11a passes through the rear wheel steering shaft 11a. It is supported by the shaft support member 21 so as to be rotatable around the axis Lr of 11a. Thereby, the rear wheel 9 is configured to be rotatable around the axis Lr together with the rear wheel support member 11 in all directions in the horizontal direction, and the rolling direction can be freely changed in all the horizontal directions. Has been done. The shaft core Lr constitutes the "second shaft core" in the present invention.
Further, the shaft core Lr is inclined so that the upper part thereof is located ahead of the lower part. As shown in FIG. 2, the axial center Lr has a rear wheel when the intersection point P of the virtual straight line S extending downward and the traveling road surface R of the vehicle 1 is in the forward direction of the vehicle 1. The rear wheel 9 is arranged in front of the ground contact point Q of the rear wheel 9 in the rolling direction of the rear wheel 9. Due to this arrangement relationship, the rear wheel 9 can roll while following the traveling of the vehicle 1 while directing the proper traveling direction.

  As shown in FIG. 2, the step 15 includes a base plate 15a that is attached to the frame body 13 and an upper plate 15b that is arranged above the base plate 15a. The occupant stands on the top plate 15b. Between the base plate 15a and the top plate 15b, a plurality of load sensors 33 ... Which detect a load applied to the top plate 15b when an occupant stands up are arranged. The number of the load sensors 33 to be provided may be any number as long as it is possible to obtain the load distribution of the front, rear, left, and right applied to the upper surface plate 15b, and at least three. In the case of three pieces, two pieces are arranged at positions spaced apart in the left-right direction on either the front side or the rear side on the base plate 15a, and one piece is arranged at the center position in the left-right direction on the other side.

  An isosceles triangular handle 35 is attached to the upper end of the handle post 19. The handle 35 includes a handle body 35a and a grip 35b rotatable with respect to the handle body 35a. The grip 35b is arranged at a portion corresponding to the base of the isosceles triangle and can be gripped by a passenger by hand. The grip 35b is configured to be rotatable around the axis of the grip 35b by the force of the occupant's hand, and when the force of the hand is loosened, the grip 35b is returned to the neutral position by the spring force of a torsion spring (not shown). It is configured. A grip rotation sensor 37 (see FIG. 5) for detecting a rotation angle (including a rotation direction) about an axis of the grip 35b and a neutral position is provided in the handle body 35a.

  A traveling mode changeover switch 39 for switching the traveling mode of the vehicle 1 is provided near the lower part of the handlebar 35 of the handlebar post 19. The traveling mode changeover switch 39 can be selectively switched by the occupant to one of "stop", "low speed traveling mode" and "high speed traveling mode". At the upper end of the handle post 19, a handle turning force sensor 41 for detecting the turning force for turning the handle 35 around the axis of the handle post 19 including the turning direction is arranged. It is set up.

A front rotation sensor 45 (see FIG. 5) that detects a rotation angle when the front wheel support member 5 rotates relative to the shaft support member 17 is provided in the shaft support member 17 of the vehicle body frame 7. Has been done.
A resistance imparting device 47 is disposed coaxially with the axis Lf of the front wheel steering shaft 23, and the resistance imparting device 47 causes the front wheel support member 5 to have an axis Lf due to a difference in driving force between the front wheels 3. Generates resistance that resists the turning force of turning around. The resistance imparting device 47 constitutes “resistance imparting means” in the present invention. The magnitude of the resistance force of the resistance imparting device 47 is configured to be adjustable from substantially 0 to a predetermined magnitude according to the driving situation of the vehicle, and with respect to the shaft support member 17, depending on the magnitude of the resistance force. It becomes difficult for the front wheel support member 5 to relatively rotate. Therefore, by appropriately controlling the driving force applied to each front wheel 3 and the resistance force against the steering force of the front wheels 3, it is possible to steer the front wheels 3 and the rear wheels 9 in accordance with the driving situation of the vehicle 1. Can be controlled. Further, since the rear wheels 9 are configured so that the rolling direction can be freely changed, the responsiveness when the rear wheels 9 are steered by the yaw moment due to the difference in the driving force of the front wheels 3 becomes good.

On the other hand, in the shaft support member 21 at the rear end of the vehicle body frame 7, a rear rotation sensor 49 that detects a rotation angle when the rear wheel support member 11 rotates relative to the shaft support member 21. (See FIG. 5).
A rotation angle regulating device 99 described later is attached to the upper end of the shaft support member 21. The rotation angle regulation device 99 is disposed coaxially with the axis Lr of the rear wheel steering shaft 11 a, and is a range of angles in which the rear wheel support member 11 can rotate relative to the shaft support member 21. Is configured to be changeable. By changing the angle range in which the rear wheel support member 11 can rotate by the rotation angle regulation device 99, the range of the rolling direction in which the rear wheel 9 can be directed is also changed. Therefore, the rotation angle regulation device 99 constitutes the "rolling direction range changing means" in the present invention.

Further, the rear wheel support member 11 is provided with a rear wheel rotation sensor 53 (see FIG. 5) that detects the rotation speed of the rear wheel 9. The traveling speed of the vehicle 1 is obtained based on the value detected by the rear wheel rotation sensor 53. The rear wheel rotation sensor 53 is omitted, the rotation speeds of the rotation shafts of the electric motors 29 are respectively detected, and the traveling speed of the vehicle 1 is calculated by calculating the average value of the detected values. May be.
An electromagnetic brake 55 for braking the rear wheel 9 is provided on the axle of the rear wheel 9. The electromagnetic brake 55 is configured such that the magnetic force continuously increases and decreases according to the supplied electric power. The larger the supplied electric power, the larger the magnetic force and the smaller the braking force. When the electric power is cut off, the maximum braking force is applied by the spring force of the spring member in the electromagnetic brake 55. Instead of the electromagnetic brake 55, a drum brake or a disc brake may be operated by driving an electric motor to generate a braking force.

  As shown in FIGS. 6 and 7, the resistance imparting device 47 includes an annular base member 61 rotatably supported by the front wheel turning shaft 23 via a bearing member 59, and the base member 61. A cylinder 63 integrally connected to the upper surface, a partition wall 65 integrally connected to the upper end of the front wheel steering shaft 23, and a screw shaft arranged coaxially with the axis Lf of the front wheel steering shaft 23. 67 and an electric actuator 69 for moving the screw shaft 67 back and forth in a direction along the axis Lf. The front end portion of the front wheel support member 5 at the central portion in the left-right direction is bonded to the outer peripheral surface of the base member 61. The cylinder 63 has an annular cylinder body 63a having an axis coaxial with the axis Lf, and an upper surface portion 63b and a lower surface portion 63c that liquid-tightly close the upper opening and the lower opening of the cylinder body 63a. A movable partition 63d integrally formed with the cylinder body 63a is provided so as to project from the inner peripheral surface of the cylinder body 63a toward the axis thereof. An oil chamber 71 that stores hydraulic oil is formed in the cylinder 63.

  The partition wall 65 is integrally formed with a cylindrical shaft portion 65a having an axis coaxial with the axis Lf, and the shaft portion 65a so as to project from the shaft portion 65a toward the inner peripheral surface of the cylinder body 63a. The partition wall portion 65b is formed. The facing surface of the movable partition wall portion 63d facing the outer peripheral surface of the shaft portion 65a is formed in an arc shape along the outer peripheral surface of the shaft portion 65a, and is configured to be slidably contactable with the outer peripheral surface of the shaft portion 65a. As a result, the oil chamber 71 in the cylinder 63 is divided into two oil chambers by the movable partition wall portion 63d and the partition wall 65. A cylindrical shaft hole is bored along the shaft center of the shaft portion 65a of the partition wall 65, and the cylindrical lower end of the screw shaft 67 is inserted into the shaft hole. The outer peripheral surface of the columnar lower end portion is configured to be slidably contactable with the inner peripheral surface of the shaft hole of the shaft portion 65a. The screw shaft 67 can move forward and backward with respect to the shaft portion 65a of the partition wall 65 in a direction along the shaft core of the screw shaft 67, but has a rotation-stopping structure so as to prevent relative rotation around the shaft core. Has been done. A through hole 73 is formed in the shaft portion 65a so as to be orthogonal to the axis of the shaft hole of the shaft portion 65a, and an oil chamber 71 is defined by the movable partition wall portion 63d and the partition wall 65. The two oil chambers in the cylinder 63 are communicated with each other only through the through hole 73.

  The electric actuator 69 is integrally connected to a cylindrical case 69a, a rotary shaft 69b arranged coaxially with the axis Lf of the front wheel steering shaft 23 in the case 69a, and the rotary shaft 69b. A rotor 69c arranged around the rotary shaft 69b and a stator 69d arranged around the rotor 69c and fixed to the inner peripheral surface of the case 69a are provided. A through hole is formed in the rotary shaft 69b along the axis of the rotary shaft 69b, and a female screw portion is formed on the inner peripheral surface of the through hole over the entire region in the longitudinal direction. The screw shaft 67 is screwed into the female screw portion. Power is supplied to the electric actuator 69 to rotate the rotary shaft 69b, and the screw shaft 67 moves back and forth in a direction along the axis Lf of the front wheel steering shaft 23, whereby the opening area of the through hole 73 of the shaft portion 65a is screwed. It is changed by the lower end of the shaft 67.

  Each front wheel 3 vibrates due to the unevenness of the traveling road surface, and the vibration propagates, whereby the front wheel support member 5 reciprocally rotates together with the base member 61 of the resistance imparting device 47 around the axis Lf of the front wheel steering shaft 23. Even in this case, the reciprocating rotation attenuates the reciprocating rotation due to the flow resistance when the hydraulic oil in the resistance imparting device 47 flows through the through hole 73. Therefore, the resistance imparting device 47 also functions as a steering damper for imparting a damping force to the steering system of the front wheels 3.

  As shown in FIGS. 15 and 16, the rotation angle regulating device 99 includes a heart-shaped cam 101 connected to the upper end of the rear wheel steering shaft 11a and a rod 103 that moves forward and backward by the cam surface of the cam 101. A pair of first spring member 107a and second spring member 107b that apply a spring force to the rod 103 so as to hold the rod 103 in the neutral position, and a pair of annular first electromagnetic coils 109a that generate a magnetic force. And a second electromagnetic coil 109b and a storage case 111 for storing these. The storage case 111 is bonded to the upper end surface of the shaft support member 21. The storage case 111 has a cylindrical first storage portion 111a for storing the rod 103, the spring members 107a and 107b, and the electromagnetic coils 109a and 109b, and one end surface integrally bonded to the first storage portion 111a. And a second storage portion 111b for storing the cam 101.

  The rod 103 has a round bar-shaped first small diameter portion 103a and a second small diameter portion 103b which are provided at both ends and have a smaller outer diameter, and a larger outer diameter than the small diameter portions 103a and 103b which are provided in the middle of the rod 103 in the longitudinal direction. It is provided with a cylindrical large diameter portion 103c having a diameter, and a disk-shaped armature 103d provided in the middle portion of the large diameter portion 103c in the longitudinal direction. The small diameter portions 103a and 103b, the large diameter portion 103c and the armature 103d are integrally formed with each other. The middle portion in the longitudinal direction of the first small diameter portion 103a of the rod 103 is inserted into a through hole formed in the one end surface of the second storage portion 111b, and the cylindrical roller 112 is provided at the tip of the first small diameter portion 103a. A bifurcated roller holding member 103e for rotatably supporting is coupled.

  The first spring member 107a is interposed so as to surround the first small diameter portion 103a of the rod 103 between the one end surface of the second storage portion 111b and the one end surface of the large diameter portion 103c of the rod 103. . The second spring member 107b is interposed between the disk-shaped side surface of the first storage portion 111a and the other end surface of the large diameter portion 103c of the rod 103 so as to surround the second small diameter portion 103b of the rod 103. . The first electromagnetic coil 109a is arranged so as to surround one end of the first small diameter portion 103a and the large diameter portion 103c of the rod 103 and the first spring member 107a. The second electromagnetic coil 109b is arranged so as to surround the other ends of the second small diameter portion 103b and the large diameter portion 103c of the rod 103 and the second spring member 107b.

  By selectively supplying power to either one of the pair of electromagnetic coils 109a and 109b, a magnetic force acting on the armature 103d is generated. Due to this magnetic force, the rod 103 compresses either one of the pair of spring members 107a and 107b, and advances and retreats against the spring force generated by the compression. When the supply of power to the first electromagnetic coil 109a or the second electromagnetic coil 109b is stopped, the rod 103 is moved to the neutral position by the spring force of either one of the pair of spring members 107a and 107b which has been compressed. Return.

The angle at which the rear wheel steering shaft 11a can rotate about its axis Lr is restricted to a predetermined range when the rod 103 is located at the neutral position, and the rod 103 moves most in the direction of the cam 101. When it is on, it is restricted to a narrow range including 0 ° in the center. These restrictions are performed by the roller 112 of the roller holding member 103e bonded to the rod 103 contacting the cam surface of the cam 101. When the rod 103 moves to the position farthest from the cam 101, the angle is 360 °, and the rotation of the rear wheel steering shaft 11a is not restricted. The rear wheel steering shaft 11a may be configured so that it cannot rotate at all when the rod 103 is most moved in the direction of the cam 101. Further, the magnitude of the electric power supplied to each of the electromagnetic coils 109a and 109b may be appropriately adjusted so that the distance between the cam 101 and the rod 103 can be maintained at a desired distance.
The rotation angle regulating device 99 is configured to move the rod 103 forward and backward by the magnetic force of the pair of electromagnetic coils 109a and 109b. Instead of such a configuration, the rod is driven by the rotation of the electric motor. It may be an electric motor drive mechanism that moves forward and backward. The electric motor drive mechanism in this case constitutes the "rotation angle regulation means" in the present invention.

On the other hand, a battery 75 is provided below the step 15, a control device 77 is provided in front of the battery 75, and an inertial sensor 79 is provided behind the battery 75. The control device 77 constitutes "control means" in the present invention. Power is supplied from a battery 75 to the electric motors 29, the electromagnetic brakes 55, the electric actuators 69, the control device 77 and the electromagnetic coils 109a and 109b. When the vehicle 1 is running, the inertial sensor 79 can detect the longitudinal acceleration, the lateral direction, and the vertical acceleration of the vehicle 1, and the angular velocities of the vehicle 1 in the yaw direction, the roll direction, and the pitch direction. it can.
The control device 77 includes an input unit 81 to which various detection signals are input, an arithmetic processing unit 83 that calculates various target values based on the detection signals input via the input unit 81, and the arithmetic processing unit. The controller 85 controls various control objects based on the target value calculated in 83.

  The interfaces in the input unit 81 include the load sensors 33, the grip rotation sensor 37, the traveling mode changeover switch 39, the steering wheel rotation force sensor 41, the front rotation sensor 45, the rear rotation sensor 49, and the rear rotation sensor 49 described above. The wheel rotation sensor 53 and the inertial sensor 79 are electrically connected to each other via signal lines. The control unit 85 includes an electric motor control unit 91, a resistance force control unit 93, an electromagnetic brake control unit 97, and a turning angle control unit 100, and these control units include the above-described electric motors 29 and resistance force imparting devices. 47 and the electromagnetic brake 55 are electrically connected to each other via output lines.

Next, the control by the control device 77 will be described.
First, in the state where the traveling mode changeover switch 39 is switched to the “stop” position, the power supply from the battery 75 to the control target such as the electric motor 29 and the control device 77 is cut off. Therefore, no driving force is generated in each electric motor 29, and the electromagnetic brake 55 is operating, so the vehicle 1 is stopped.
When the occupant switches the traveling mode selection switch 39, the switching signal is input to the arithmetic processing unit 83 via the input unit 81. When the arithmetic processing unit 83 determines that the mode has been switched to the “low-speed traveling mode”, the control unit 85 controls the traveling speed so that the vehicle can travel only at a speed lower than the preset reference speed V ₀ . On the other hand, when the arithmetic processing unit 83 determines that the mode has been switched to the “high-speed traveling mode”, the control unit 85 controls the traveling speed so that the vehicle can travel at the reference speed V ₀ or higher. The reference speed V ₀ can be set as appropriate, and can be, for example, 4 km / hour.

<In low speed mode>
In the low-speed running mode, the detection values detected by the load sensors 33, the rear rotation sensor 49, and the rear wheel rotation sensor 53 when the occupant stands in step 15 are processed by the arithmetic processing unit 83 via the input unit 81. Entered in. Based on the input detected values, the arithmetic processing unit 83 obtains the target speed when the vehicle 1 travels and the target turning amount when the running vehicle 1 turns. The turning amount includes, for example, a turning radius that the center of the vehicle 1 passes when the vehicle 1 turns. The target turning amount means a target turning radius when the vehicle 1 turns. The signals of the obtained target speed and target turning amount are transmitted to the electric motor control unit 91 of the control device 89, and each electric motor 29 is controlled by the electric motor control unit 91 based on the transmitted target speed and target turning amount. It

  In detail, each detection value detected by each load sensor 33 is input to the arithmetic processing unit 83 via the input unit 81, and the arithmetic processing unit 83 obtains the load distribution of the occupant to step 15. If the arithmetic processing unit 83 determines that the load distribution is biased toward the front end side from the rear end side in step 15, the result is input to the electric motor control unit 91, and the electric motor control is performed. The electric motors 29 are controlled by the portion 91 so that the vehicle 1 moves forward. On the contrary, when the arithmetic processing unit 83 determines that the load distribution is biased toward the rear end side from the front end side in step 15, each electric motor 29 is controlled so that the vehicle 1 moves backward. It In these cases, the driving force of each electric motor 29 is generated in accordance with the ratio of the detected value by the load sensor 33 on the front end side in step 15 and the detected value by the load sensor 33 on the rear end side. Controlled. Specifically, when the ratio of the detected values is 1, the driving force is not generated in each electric motor 29, and when the ratio of the detected values deviates from 1, the larger the amount of deviation is, the larger the drive of each electric motor 29 is. Generate force.

Further, in addition to the deviation of the load distribution toward the front end portion side or the rear end portion side in step 15, it is further calculated that the load distribution is biased toward the right end portion side from the left end portion side in step 15. If it is determined in step 15, the driving force of each electric motor 29 is distributed according to the ratio of the detection value obtained by the load sensor 33 on the left end side and the detection value obtained by the load sensor 33 on the right end side in step 15. Controlled as. Specifically, when the detected value ratio is 1, each electric motor 29 is caused to generate the same driving force. As a result, the vehicle 1 travels straight ahead. On the other hand, when the ratio of the detected values deviates from 1, the larger the deviation amount, the larger the driving force is distributed to the electric motor 29 on the side opposite to the electric motor 29 on the side where the load distribution is deviated. As a result, the vehicle 1 turns.
Then, when the vehicle 1 is traveling, each electric motor 29 is controlled by the electric motor control unit 91 so that the detection value of the rear wheel rotation sensor 53 matches the target speed. Further, when the vehicle 1 is turning, each electric motor 29 is controlled by the electric motor control unit 91 so that the detection value of the rear side rotation sensor 49 matches the target turning amount.

  Further, in the low speed traveling mode, the electric actuator 69 of the resistance imparting device 47 is controlled by the resistance force controller 93, and the through hole 73 is completely closed by the lower end of the screw shaft 67. As a result, the hydraulic oil in the oil chamber 71 can flow only through a small gap between the lower end of the screw shaft 67 and the through hole 73, and therefore the base member for the front wheel steering shaft 23 and the partition wall 65. The largest resistance force is given when 61 and the cylinder 63 rotate relative to each other. The control of the electric actuator 69 by the resistance control unit 93 is performed on the basis of a control program previously obtained by an experiment so that the resistance changes stepwise or continuously.

  As described above, in the low speed running mode, the resistance force against the turning force of the front wheels 3 is controlled so as to be larger than that in the high speed running mode described later, and the front wheel support member 5 is relatively moved with respect to the front wheel turning shaft 23. While the rotation is blocked, the rear wheel support member 11 is configured to be freely rotatable with the rear wheel 9 around the axis Lr of the rear wheel steering shaft 11a. Therefore, when the vehicle 1 turns in the low speed running mode, the following occurs. First, when the straight traveling state shown in FIG. 8A is changed to the turning traveling, the electric motor control unit is configured to generate a large driving force in the electric motor 29 of the front wheel 3 located on the outer side in the turning direction than on the inner side in the turning direction. Each electric motor 29 is controlled by 91.

  As a result, a yaw moment in the turning direction is generated in the vehicle 1 due to the difference in driving force between the electric motors 29, and as shown in FIGS. 8B and 9, the rear wheel 9 is moved by the yaw moment. The rear wheel supporting member 11 and the vehicle body frame 7 are rotated relative to each other about the axis Lr (clockwise). As a result, the rear wheels 9 can be smoothly steered, so that the vehicle 1 can be turned with a relatively small turning radius, and a small turn can be made even in a narrow place. Further, at this time, since the front wheel support member 5 hardly rotates around the axis Lf of the front wheel steering shaft 23, as shown in FIG. 10, the vehicle 1 can turn without traveling in the left-right direction. Therefore, it is possible to improve turning performance during low-speed traveling. The turning radius when the vehicle 1 travels fluctuates according to the difference in the driving force between the electric motors 29, and the larger the difference, the smaller the turning radius. You can also turn.

  When the electric motors 29 are controlled by the electric motor control unit 91 so that the driving forces of the electric motors 29 become equal to each other while the vehicle 1 is turning, a yaw moment opposite to the turning direction is applied to the vehicle 1. Occur. Then, as shown in FIG. 8C, the yaw moment causes the rear wheel 9 together with the rear wheel support member 11 to rotate relative to the vehicle body frame 7 around the axis Lr (counterclockwise), The vehicle 1 returns from turning to straight traveling (see FIG. 8D).

  In the low-speed traveling mode, the rotation angle control unit 100 controls the rotation angle control unit 100 so that power is not supplied from the battery 75 to either of the pair of electromagnetic coils 109a and 109b in the rotation angle regulation device 99. The rod 103 is held in a neutral position by a pair of spring members 107a and 107b. For this reason, in the low speed traveling mode, the angle at which the rear wheel steered shaft 11a can rotate about its axis Lr is restricted to a predetermined range including the straight traveling direction at the center. As a result, in the low speed traveling mode, the rear wheel steered shaft 11a becomes rotatable with the rear wheels 9 around the axis Lr within a predetermined angle range including the straight traveling direction at the center when the vehicle 1 turns. Therefore, the rear wheel 9 is steered freely within a predetermined angle range, and the maneuverability of the vehicle 1 can be improved. Further, since the turning angle regulation device 99 changes the range of the rolling direction of the rear wheel 9, the rolling direction of the rear wheel 9 can be freely changed within the range, so that the turning angle regulating device 99 can be rotated. By providing the angle regulation device 99, the responsiveness when steering the rear wheels 9 is not impaired by the yaw moment due to the difference in the driving force of the front wheels 3.

  When the electric motors 29 are controlled so that the vehicle 1 moves backward in the low speed traveling mode, the rotation angle control unit 100 controls the second electromagnetic coil 109b so that the battery 75 supplies power. . As a result, the rod 103 of the rotation angle regulation device 99 moves against the second spring member 107b and is held at the position farthest from the cam 101. As a result, the angle at which the rear wheel steering shaft 11a can rotate about its axis Lr becomes 360 °, so that the rear wheel steering shaft 11a moves together with the rear wheel 9 around its axis Lr as the vehicle 1 moves backward. When rotated, the rear wheel 9 turns 180 degrees from the state shown in FIG. 2 and comes closest to step 15. Therefore, the reverse movement of the vehicle 1 is smoothly performed.

<In high speed mode>
On the other hand, in the high speed running mode, the grip rotation sensor 37, the handle rotation force sensor 41, the front rotation sensor 45, the rear rotation sensor 49, the rear wheel rotation sensor 53, and the inertia sensor 79 are used instead of the load sensor 33 in step 15. Each electric motor 29 is driven based on each detection value detected by. These detected values are input to the arithmetic processing unit 83 via the input unit 81, and the target speed when the vehicle 1 travels and the target turning amount when the traveling vehicle 1 turns are calculated. Required by. The signals of the obtained target speed and target turning amount are transmitted to the electric motor control unit 91 of the control device 89, and each electric motor 29 is controlled by the electric motor control unit 91 based on the transmitted target speed and target turning amount. It Further, the current speed and the turning amount are respectively obtained by the arithmetic processing unit 83 based on the respective detection values detected by the front rotation sensor 45, the rear rotation sensor 49, the rear wheel rotation sensor 53 and the inertial sensor 79, Each electric motor 29 is controlled by the electric motor control unit 91 so that these values match the target speed and the target turning amount.

  In the high-speed traveling mode, when the grip 35b is rotated from the neutral position, the rotation direction and the rotation angle from the neutral position are detected by the grip rotation sensor 37. The detected value detected is input to the arithmetic processing unit 83 via the input unit 81, and the electric motor 29 is controlled by the control unit 85 based on the detected value. When the grip 35b is rotated in the rotation direction opposite to the rotation direction of the front wheels 3 when the vehicle 1 moves forward, the electric motor 29 is controlled in the movement direction. At that time, the electric motor 29 is controlled such that the traveling speed becomes faster as the turning angle of the grip 35b becomes larger. When the grip 35b is rotated in the opposite direction from the neutral position, the electric motor 29 is controlled so that the larger the rotation angle is, the larger the regenerative electric power is generated and the larger regenerative braking force is applied to the vehicle 1. At this time, the electromagnetic brake controller 97 may drive the electromagnetic brake 55 of the rear wheel 9 to supplement the regenerative braking of the front wheel 3 by the electric motor 29. Further, even when the vehicle 1 is to be stopped urgently, the regenerative braking of the front wheels 3 by the electric motor 29 and the braking of the rear wheels 9 by the electromagnetic brake 55 may be simultaneously operated.

  Further, in the high speed traveling mode, the electric actuator 69 of the resistance imparting device 47 is automatically controlled by the resistance force control unit 93 so that the lower end portion of the screw shaft 67 retracts from the through hole 73 and the through hole 73 is completely opened. To be done. As a result, the hydraulic oil in the oil chamber 71 can flow without resistance through the through hole 73, so that the relative rotation of the base member 61 and the cylinder 63 with respect to the front wheel steering shaft 23 and the partition wall 65 is also allowed without resistance. It As a result, the front wheel support member 5 connected to the base member 61 is also allowed to rotate relative to the front wheel steering shaft 23 without resistance.

  Therefore, as shown in FIG. 11A, when the vehicle 1 traveling straight ahead makes a turn, a large driving force is generated in the electric motor 29 of the front wheel 3 located on the outer side in the turning direction than on the inner side in the turning direction. When the electric motors 29 are controlled by the electric motor control unit 91, the front wheels 3 and the front wheel supporting member 5 are easily rotated relative to the front wheel steering shaft 23 due to the difference in driving force between the electric motors 29. (See FIG. 11B). At this time, since the front wheel support member 5 rotates around the axis Lf of the front wheel steered shaft 23 that leans forward, the body frame 7 leans inward in the turning direction. Can be improved (see FIG. 12).

  As described above, when the vehicle 1 travels in the high speed traveling mode, the resistance force against the steering force of the front wheels 3 is controlled to be smaller than that in the low speed traveling mode. The yaw moment due to the difference in the driving force acts to rotate the front wheel support member 5 around the axis Lf with respect to the vehicle body frame 7. Therefore, since the steering by the rear wheels 9 is suppressed and the steering is mainly performed by the front wheels 3, it is possible to secure the turning performance in the high speed traveling mode. Further, in the high-speed traveling mode, the rotation angle control unit 100 controls the first electromagnetic coil 109a of the rotation angle regulation device 99 so that power is supplied from the battery 75. As a result, the rod 103 of the rotation angle regulation device 99 moves against the first spring member 107a and is held at the position closest to the cam 101. For this reason, the angle at which the rear wheel steering shaft 11a can rotate about its axis Lr is restricted to a narrow range including the straight-ahead direction in the center, so that the range of the rolling direction in which the rear wheel 9 can be directed is the low speed traveling mode. It becomes narrower than when. As a result, it is possible to prevent the rear wheel 9 from undesirably largely turning around the axis Lr, and reduce the influence of a disturbance such as a side wind or undulation of the road surface when the vehicle 1 is traveling at high speed. can do.

  Further, when the body frame 7 is tilted inward in the turning direction, the axis Lr, which is the rotation center of the rear wheel support member 11, is also tilted. The axis Lr is inclined so that the upper part is located in front of the lower part, and the intersection point P of the extended virtual straight line S and the traveling road surface R is forward from the ground contact point Q of the rear wheel 9 in the rolling direction of the rear wheel 9. Is located in. Therefore, the reaction force of the rear wheel 9 in the vertical direction from the traveling road surface R at the ground contact point Q causes the rear wheel support member 11 to rotate around the axis Lr via the rear wheel 9 to cause the rear wheel 9 to rotate. It acts so that the front side in the rolling direction is directed in the inclination direction of the vehicle body frame 7. As a result, the rear wheels 9 do not excessively point in the direction opposite to the inclination direction, and the vehicle 1 can stably turn.

On the other hand, the centrifugal force that acts on the vehicle 1 when the vehicle 1 turns is balanced with the frictional force between the front wheels 3 and the rear wheels 9 and the traveling road surface R, but the centrifugal force between the rear wheels 9 and the traveling road surface R is large. The frictional force acts on the rear wheel 9 such that the front side in the rolling direction of the rear wheel 9 is directed outward in the turning direction. Therefore, the direction of the rear wheels 9 when the vehicle 1 is turning is such that the reaction force upward in the vertical direction from the traveling road surface R acting on the contact point Q with the traveling road surface R of the rear wheels 9 and the traveling direction. It is determined by the frictional force with the road surface R.
When the front side of the rolling direction of the rear wheel 9 is directed outward in the turning direction, the turning radius becomes smaller, whereas when it is directed toward the inner side of the turning direction, the rolling direction of the front wheel 3 and the rolling direction of the rear wheel 9 become parallel. Since the vehicle approaches to, the course of the vehicle 1 can be smoothly changed.

  Further, as described above, the camber shafts 25 incline so that their front portions are located lower than their rear portions, and the respective motor housings 27 interpose the camber link members 31 and the frame main body 13 of the vehicle body frame 7. Are connected to each. Therefore, when the front wheels 3 rotate relative to the front wheel steering shaft 23 together with the front wheel support member 5, the toe angle of each front wheel 3 becomes a toe-in state while the front wheels 3 located outside in the turning direction are in the turning direction. The front wheel 3 located at is in a toe-out state. This also contributes to the improvement of turning performance. At the same time, each front wheel 3 inclines inward in the turning direction. That is, the front wheels 3 located inside the turning direction serve as positive cambers, and the front wheels 3 located outside the turning direction serve as negative cambers. As a result, the gripping force of each front wheel 3 on the traveling road surface during turning can be improved.

  When the electric motors 29 are controlled by the electric motor control unit 91 so that the driving forces of the electric motors 29 become equal to each other while the vehicle 1 is turning, the front wheels 3 are moved relative to the front wheel steering shaft 23. Is relatively rotated in the straight traveling direction together with the front wheel support member 5, and the vehicle 1 returns from the turning traveling to the straight traveling (see FIG. 11C). At this time, by temporarily driving the electromagnetic brake 55 of the rear wheel 9 by the electromagnetic brake control unit 97, the front wheel support member 5 is rotated around the axis Lf of the front wheel steering shaft 23 so as to direct in the straight traveling direction. Since the moment to be generated is generated, the directing direction of each front wheel 3 and the front wheel supporting member 5 can be quickly returned to the straight traveling direction.

Here, the relationship between the magnitude of the resistance force of the resistance imparting device 47 and the turning amounts on the front wheel 3 side and the rear wheel 9 side will be described with reference to FIG. 13. This figure shows the characteristics when the vehicle 1 turns while keeping the difference in driving force between the electric motors 29 at a constant value, and the steering amount on the front wheel 3 side and the rear wheel 9 side is the vertical axis. The horizontal axis represents the resistance force applied by the resistance force application device 47. The turning amount on the front wheel 3 side is a turning angle when the front wheel support member 5 turns about the axis Lf of the front wheel turning shaft 23, and corresponds to the absolute value of the detection value of the front turning sensor 45. . On the other hand, the turning amount on the rear wheel 9 side is a turning angle when the rear wheel supporting member 11 turns around the axis Lr of the rear wheel turning shaft 11 a, and is a value detected by the rear turning sensor 49. Corresponds to an absolute value. In FIG. 13, the characteristic indicated by the broken line is the steering amount on the front wheel 3 side, and the characteristic indicated by the solid line is the steering amount on the rear wheel 9 side.
As can be seen from this figure, in the state where the difference in the driving force between the electric motors 29 is maintained at a constant value, the smaller the resistance force of the resistance imparting device 47 is, the larger the steering amount on the front wheel 3 side and the rear wheel 3 The steering amount on the wheel 9 side is reduced. Then, as the resistance of the resistance imparting device 47 increases, the steering amount on the front wheel 3 side decreases and the steering amount on the rear wheel 9 side increases, and eventually the steering amount on the front wheel 3 side becomes smaller. The steering amount on the rear wheel 9 side reverses and the steering amount on the rear wheel 9 side becomes larger than the steering amount on the front wheel 3 side.

  Next, with reference to FIG. 14, regarding changes in the amount of steering on the front wheel 3 side and the rear wheel 9 side when the difference in driving force between the electric motors 29 and the resistance force of the resistance force application device 47 are changed. And explain. In this figure, the horizontal axis represents time, the vertical axis represents the difference in driving force between the electric motors 29 in graph (A), and the resistance of the resistance imparting device 47 in graph (B). In (C), the steering amounts on the front wheel 3 side and the rear wheel 9 side are respectively taken. On the horizontal axis, Th time is a time zone in which the traveling mode changeover switch 39 is switched to the high speed traveling mode and the vehicle 1 is traveling at high speed, and Tl time is the traveling mode changeover switch 39 is set to the low speed traveling mode. It is a time zone in which the vehicle 1 is switched at a low speed, and during the Tm time, the vehicle 1 is driven at a medium speed intermediate between the high speed and the low speed by switching the driving mode changeover switch 39 to the high speed driving mode. Is the time zone in which the vehicle is running.

  The graph (A) showing the difference in driving force is the case where the vehicle 1 turns leftward on the upper side and the vehicle 1 turns rightward on the lower side around 0. In the graph (C) showing the steered amount, the steered amount on the front wheel 3 side is a turning angle when the front wheel support member 5 turns around the axis Lf of the front wheel turning shaft 23. It corresponds to the detection value of the sensor 45. On the other hand, the turning amount on the rear wheel 9 side is a turning angle when the rear wheel supporting member 11 turns around the axis Lr of the rear wheel turning shaft 11 a, and is a detection value of the rear turning sensor 49. Equivalent to. In the graph (C) showing the turning amount, the characteristic indicated by the broken line is the turning amount on the front wheel 3 side, and the characteristic indicated by the solid line is the turning amount on the rear wheel 9 side. The turning amount of the front wheel 3 side is the case where the upper side is rotated counterclockwise around 0, and the lower side is the case where it is rotated clockwise. On the other hand, the steering amount on the rear wheel 9 side is the case where the upper side is rotated clockwise around 0, and the lower side is the case where it is rotated counterclockwise.

  As can be seen from this figure, at time t1 in the high speed time zone, a difference in driving force is imparted so that the vehicle 1 turns to the left, the resistance force of the resistance imparting device 47 is minimum, and the front wheel 3 The turning amount on the side shows a large value in the counterclockwise direction, and the turning amount on the rear wheel 9 side shows a small value in the clockwise direction. Further, at time t2 in the medium speed time period, the difference in the driving force applied so that the vehicle 1 turns to the left is in the process of decreasing toward 0, and the resistance of the resistance applying device 47 is reduced. The force is between the minimum and the maximum, the turning amount on the front wheel 3 side shows a constant value in the counterclockwise direction, and the turning amount on the rear wheel 9 side shows a constant value in the clockwise direction. At time t3 in the medium speed period, the difference between the driving forces applied to turn the vehicle 1 to the right is in the process of decreasing toward 0, and the resistance of the resistance imparting device 47 is reduced. The force is about intermediate, the turning amount on the front wheel 3 side shows a constant value in the clockwise direction, and the turning amount on the rear wheel 9 side shows a constant value in the counterclockwise direction. Further, at time t4 in the high speed time zone, the difference in the driving force applied so that the vehicle 1 turns rightward is in the process of increasing, and the resistance force of the resistance imparting device 47 is maximum. Yes, the steering amount on the front wheel 3 side is 0, and the steering amount on the rear wheel 9 side shows a constant value in the clockwise direction and is in the process of decreasing toward 0.

  Next, first to fifth modified examples will be described below with reference to FIGS. 17 to 22 as modified examples for modifying the above-described embodiment. In the drawings referred to in the description of these modified examples, the same or equivalent members, parts, directions, and the like as those described in the above embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. The difference from the form will be mainly described in detail. Needless to say, in these modified examples as well, the same actions and effects as the configurations described in the above-described embodiment can be obtained.

(First modification)
In the above-described embodiment, in the high-speed traveling mode, the resistance imparting device 47 is controlled so that the relative rotation of the front wheel supporting member 5 with respect to the front wheel turning shaft 23 is allowed without resistance, so that the vehicle 1 turns. In such a case, the vehicle 1 was steered mainly by the front wheels 3. However, the rear wheels 9 may be steered in addition to the steering by the front wheels 3. In detail, the control is as follows.
First, when the vehicle 1 is traveling straight ahead, the resistance control unit 93 controls the resistance applying device 47 so that the resistance becomes smaller.
Next, when the vehicle 1 shifts from straight traveling to turning traveling, the electric motor control unit 91 causes each electric motor to generate a large driving force for the electric motor 29 of the front wheel 3 located on the outer side in the turning direction from the inner side in the turning direction. 29 is controlled (see FIG. 17A). Then, a yaw moment in the turning direction is generated in the vehicle 1 due to the difference in driving force between the electric motors 29, and the front wheel support member 5 rotates around the axis Lf of the front wheel steering shaft 23.

  Next, the resistance force control unit 93 controls the resistance force imparting device 47 so that the largest resistance force is generated at a predetermined timing until the current turning amount reaches the target turning amount obtained by the arithmetic processing unit 83. Control. As a result, a yaw moment in the turning direction is generated in the vehicle body frame 7 due to the difference in the driving force between the electric motors 29, and the yaw moment causes the rear wheel 9 together with the rear wheel support member 11 to the axis Lr with respect to the vehicle body frame 7. It acts so as to rotate relatively (clockwise) relative to each other (see FIG. 17B). At this time, the angle by which the rear wheel steering shaft 11a can rotate about its axis Lr is restricted to a narrow range including the straight traveling direction at the center by the control by the rotation angle control unit 100, but within that range, The wheels 9 can also be steered. As a result, not only the front wheels 3 but also the rear wheels 9 are steered, so that the turning performance of the vehicle 1 can be improved. Such control is suitable when traveling on a road where a plurality of curves with different turning directions are continuous.

  When the vehicle 1 that is turning is returned to straight travel, as shown in FIG. 17C, the resistance by the resistance imparting device 47 is controlled to be small, and the electric motors 29 of the respective electric motors 29 are driven. Each electric motor 29 is controlled so that the driving forces become equal to each other. Then, the front wheels 3 are relatively rotated in the straight traveling direction together with the front wheel support member 5 with respect to the front wheel steering shaft 23. At this time, by temporarily driving the electromagnetic brake 55 of the rear wheel 9 by the electromagnetic brake control unit 97, the front wheel support member 5 is rotated around the axis Lf of the front wheel steering shaft 23 so as to direct in the straight traveling direction. Since a moment to be caused and a moment to rotate the rear wheel support member 11 around the axis Lr of the rear wheel steering shaft 11a are generated, the directing directions of the front wheels 3 and the rear wheels 9 are quickly returned to the straight traveling directions. (See FIG. 17C). Then, the vehicle 1 returns from the turning traveling to the straight traveling (see FIG. 17D).

(Second modified example)
In the second modification, when the vehicle 1 turns in the high-speed traveling mode, the electric motor control unit 91 controls the electric motors 29 and the resistance force control unit 93 controls the resistance applying device 47. The method is different from that of the embodiment and the first modification. In detail, the control is as follows.
First, when the vehicle 1 is traveling straight ahead, the resistance control unit 93 controls the resistance applying device 47 so that the resistance becomes smaller.
Next, when the vehicle 1 shifts from straight traveling to turning traveling, the electric motor control unit 91 causes each electric motor to generate a large driving force for the electric motor 29 of the front wheel 3 located on the outer side in the turning direction from the inner side in the turning direction. 29 is controlled (see FIG. 18A). Then, a yaw moment in the turning direction is generated in the vehicle 1 due to the difference in driving force between the electric motors 29, and the front wheel support member 5 rotates around the axis Lf of the front wheel steering shaft 23.

  Next, the resistance force control unit 93 controls the resistance force imparting device 47 so that the largest resistance force is generated at a predetermined timing until the current turning amount reaches the target turning amount obtained by the arithmetic processing unit 83. Simultaneously with the control, each electric motor 29 is controlled by the electric motor control unit 91 so that a large driving force is generated in the electric motor 29 of the front wheels 3 located inside the turning direction from outside the turning direction (FIG. 18 (B)). reference). As a result, a yaw moment in a direction opposite to the turning direction is generated in the vehicle 1 due to the difference in driving force between the electric motors 29, and the yaw moment causes the rear wheel 9 together with the rear wheel support member 11 to the vehicle body frame 7. And operates so as to relatively rotate around the axis Lr (counterclockwise in FIG. 18B). At this time, the angle by which the rear wheel steering shaft 11a can rotate about its axis Lr is restricted to a narrow range including the straight traveling direction at the center by the control by the rotation angle control unit 100, but within that range, The wheels 9 can also be steered. As a result, since the rolling direction of the front wheels 3 and the rolling direction of the rear wheels 9 approach a parallel state, the course of the vehicle 1 can be smoothly changed. FIG. 19 shows a state in which the vehicle 1 at this time is viewed from above. Such control is suitable when changing lanes between a plurality of lanes.

  When the vehicle 1 that is turning is returned to straight travel, as shown in FIG. 18C, the resistance by the resistance imparting device 47 is controlled to be small and the electric motors 29 of the respective electric motors 29 are driven. Each electric motor 29 is controlled so that the driving forces become equal to each other. Then, the front wheels 3 are relatively rotated in the straight traveling direction together with the front wheel support member 5 with respect to the front wheel steering shaft 23. At this time, by temporarily driving the electromagnetic brake 55 of the rear wheel 9 by the electromagnetic brake control unit 97, the front wheel support member 5 is rotated around the axis Lf of the front wheel steering shaft 23 so as to direct in the straight traveling direction. Since a moment to be caused and a moment to rotate the rear wheel support member 11 around the axis Lr of the rear wheel steering shaft 11a are generated, the directing directions of the front wheels 3 and the rear wheels 9 are quickly returned to the straight traveling directions. (See FIG. 18C). Then, the vehicle 1 returns from the turning traveling to the straight traveling (see FIG. 18D).

(Third Modification)
In the third modification, when the vehicle 1 turns in the high speed traveling mode, the electric motor control unit 91 controls the electric motors 29 and the resistance force control unit 93 controls the resistance applying device 47. The method is different from that of the above-described embodiment and the first and second modified examples.
More specifically, the control is performed in two stages as shown by the solid lines in graphs (A) to (C) of FIG. In these graphs, the characteristic indicated by the broken line shows the characteristic when the two-step control is not performed. In these graphs, the horizontal axis represents time, the vertical axis represents the difference in driving force between the electric motors 29 in graph (A), and the resistance force by the resistance imparting device 47 in graph (B). In the graph (C), the steering amount on the front wheel 3 side is taken.

  The graph (A) shows a case where a difference in driving force is given so that the vehicle 1 travels in the turning direction on the upper side around 0, and the lower side shows the driving force so that the vehicle 1 travels in the anti-turning direction. This is the case when a difference is given. The turning amount on the front wheel 3 side in the graph (C) is a turning angle when the front wheel support member 5 turns about the axis Lf of the front wheel turning shaft 23, and is a detected value of the front turning sensor 45. Equivalent to. In the graph (C), the turning angle in the turning direction increases as it goes upward.

  First, as the control in the first stage, when the turning is started in the high speed traveling mode, the resistance force control unit 93 temporarily controls the resistance imparting device 47 so that the resistance becomes larger than that in the low speed traveling mode (graph). (See E in (A)). At this time, it is preferable to control so as to maximize the resistance force. With this control, the electric motor control unit 91 controls the electric motors so that the driving force applied to each front wheel 3 is smaller for the front wheels 3 located on the outer side in the turning direction than for the front wheels 3 located on the inner side in the turning direction. 29 (see F in graph (B)). That is, the difference in the driving force applied to each front wheel 3 temporarily acts to drive the vehicle 1 in the counter-turning direction. As a result, the load on the traveling road surface of the front wheels 3 located on the outer side in the turning direction from the front wheels 3 located on the inner side in the target turning direction temporarily increases, so that the increased load causes the front wheel support member 5 to temporarily move. The elastically deforms and bends, and the front wheel 3 located outside in the turning direction also elastically deforms and dents.

  After that, subsequently, as the control in the second stage, the resistance control unit 93 controls the resistance applying device 47 so that the resistance becomes smaller (see G in the graph (A)). Then, along with this control, the electric motor control unit 91 is configured such that the driving force applied to each front wheel 3 is greater in the front wheel 3 located outside in the turning direction than in the front wheel 3 located inside the target turning direction. To control each electric motor 29 (see H in graph (B)). Such control in the second stage is performed as it is at high speed without reducing the traveling speed of the vehicle 1. As a result, the front wheel 3 is rotated relative to the front wheel steering shaft 23 together with the front wheel support member 5 due to the difference in driving force between the electric motors 29. At this time, the restoring force that causes the front wheel support member 5 and the front wheel 3 which have been temporarily elastically deformed by the control in the first step to return to the original state is controlled by the front wheel 3 and the front wheel 3 in the second step control. It can be used as a force for rotating the front wheel support member 5 relative to the front wheel steering shaft 23. Therefore, not only can the front wheels 3 be steered by that much, but there is no need to provide a special device for assisting the steering of the front wheels 3.

In the graph (C) of FIG. 20, this is indicated by the characteristics shown by the solid line when the above-described two-step control is performed and the broken line when the two-step control is not performed (in the case of the embodiment). It is clear when compared with the characteristics shown.
In addition, when it is desired to return the vehicle 1 from turning to straight traveling, as a first step, the resistance of the resistance imparting device 47 is temporarily controlled to increase and the driving force applied to each front wheel 3 is temporarily increased. After controlling the electric motors 29 so as to steer the front wheels 3 in the anti-return direction, the resistance of the resistance imparting device 47 is controlled to be smaller as the second stage control. The difference in driving force applied to each front wheel 3 controls each electric motor 29 so as to steer each front wheel 3 in the returning direction. As a result, the vehicle 1 can be quickly returned from the turning traveling to the straight traveling.

(Fourth Modification)
In the resistance imparting device 47 described in the above embodiment, the screw shaft 67 is moved forward and backward by driving the electric actuator 69 to change the flow resistance when the working oil flows through the through hole 73, and thus the front wheel support member 5. The resistance force when rotating was adjusted. However, instead of this, the resistance force when the front wheel support member 5 rotates may be adjusted by a resistance force imparting device 47 ′ as shown in FIG. The resistance imparting device 47 'constitutes "turning resistance imparting means" in the present invention. The resistance imparting device 47 ′ is arranged coaxially with the axis Lf of the front wheel steering shaft 23 and is a cylindrical shaft member 115 integrally bonded to the upper end of the front wheel steering shaft 23, and a bearing member 59. An annular base member 117 that is rotatably supported by the front wheel steering shaft 23 via a cylinder, a bottomed cylindrical cylinder 119 integrally bonded to the upper surface of the base member 117, and the cylinder 119. And an electromagnetic clutch device 121 disposed inside.

  The electromagnetic clutch device 121 includes a circular tubular member 123 integrally bonded to the outer peripheral surface of the shaft member 115, and a plurality of first friction plates 125, ..., Which are arranged on the outer peripheral side of the circular tubular member 123. The second friction plates 127, the circular armature 129 and the electromagnetic coil 131, which are arranged so as to sandwich the friction plates 125 and 127, respectively, and a circle integrally connected to the inner peripheral surface of the cylinder 119. And a tubular member 133. Each of the first friction plates 125 is attached to the circular tubular member 123 such that relative rotation of the first friction plate 125 around the axial center Lf is restricted and relative movement in the direction along the axial center Lf is allowed. Has been done. Each of the second friction plates 127 is attached to the circular tubular member 133 so that relative rotation of the second friction plate 127 around the axial center Lf is restricted and relative movement is allowed in the direction along the axial center Lf. Has been done. The armature 129 is attached to each of the circular tubular members 123 and 133 so that relative rotation around the axis Lf and relative movement in the direction along the axis Lf are allowed. The electromagnetic coil 131 is bonded to the circular tubular member 123.

  In the low speed running mode, the electromagnetic clutch device 121 of the resistance applying device 47 ′ is controlled by the resistance control unit 93, the power of the battery 75 is supplied to the electromagnetic coil 131, and the magnetic force is generated in the electromagnetic coil 131. The armature 129 is strongly attracted toward the electromagnetic coil 131. As a result, each first friction plate 125 and each second friction plate 127 come into pressure contact with each other to generate a large frictional force therebetween, so that the base member 117 and the cylinder are attached to the front wheel steering shaft 23 and the shaft member 115. The greatest resistance is given when the 119 relatively rotates. The control of the electromagnetic clutch device 121 by the resistance force control unit 93 is performed based on a control program previously obtained by an experiment so that the frictional force changes stepwise or continuously.

  The configuration for adjusting the frictional force between each first friction plate 125 and each second friction plate 127 is not limited to the configuration for changing the magnetic force between the armature 129 and the electromagnetic coil 131 as described above. . For example, a magnetic fluid in which fine particles of a magnetic material are dispersed in a liquid such as water or oil is interposed between each first friction plate 125 and each second friction plate 127, and is generated by energizing an electromagnetic coil. A resistance force may be generated between each of the first friction plates 125 and each of the second friction plates 127 by causing the magnetic fluid to act on the magnetic fluid. With such a configuration, the resistance of the magnetic fluid interposed between each first friction plate 125 and each second friction plate 127 is adjusted by increasing or decreasing the power supplied to the electromagnetic coil to adjust the strength of the magnetic field. The force can be adjusted accordingly.

(Fifth Modification)
The rear wheel 9 described in the above-described embodiment has the rear wheel support member 11 that supports the rear wheel 9 rotatably supported in the vehicle body frame 7 in all horizontal directions. It was configured to be able to roll in the direction of. However, the rear wheel that can roll in all horizontal directions is not limited to the rear wheel 9 of the above-described embodiment. For example, a rear wheel 9'as shown in FIG. 22 may be adopted. The rear wheel 9'is composed of an omni wheel and is rotatably supported by a rear wheel support member 11 'which is connected to the vehicle body frame 7. The rear wheel 9'includes a pair of annular rolling elements in which a plurality of barrel-shaped rolling rollers 135 are arranged at equal angular intervals in the circumferential direction around the axle. Since each rolling roller 135 is individually rotatably supported by the annular retainer that constitutes a part of the rolling element, each rolling roller 135 can roll in the direction orthogonal to the axis of the rolling roller 135. Further, the circumferential array position of each rolling roller 135 on the rolling element is deviated between the pair of rolling elements, so that when the rolling element rolls, each rolling roller 135 is continuous without interruption. Since it comes into contact with the road surface, it can roll smoothly. Even with the rear wheel 9 ′ composed of such an omni wheel, the rolling direction can be freely changed in all horizontal directions.
In addition, in the case of the fifth modified example, unlike the above-described embodiment, since the rotation angle regulation device 99 capable of changing the range of the rolling direction in which the rear wheel 9 can be directed is not provided, the vehicle 1 The rear wheels 9 can roll in all horizontal directions without distinction between the low-speed traveling mode and the high-speed traveling mode.

  The above-described embodiment and the first to fifth modified examples are examples for explaining the present invention, and the present invention is not limited to the above-described embodiment and the modified examples, and the claims and the specification. The invention can be appropriately modified within a range that does not contradict the gist or concept of the invention that can be read from the entire description, and the vehicle after such modification is also included in the technical scope of the invention.

  For example, in the above-described embodiment and each modification, the load sensor 33, the grip rotation sensor 37, the handle rotation force sensor 41, the front rotation sensor 45, the rear rotation sensor 49, the rear wheel rotation sensor 53, and the inertia sensor 79. An example in which the target speed and the target turning amount of the vehicle 1 and the current speed and the turning amount of the vehicle 1 are obtained by the arithmetic processing unit 83 in the control device 77 has been shown. However, instead of this, map information stored in advance in a memory (not shown) in the control unit 85, position information acquired by the global positioning system (GPS), travel regulation information in the travel area, and the vehicle 1 are stored. The target speed and the target turning amount of the vehicle 1, the current speed and the turning based on the image information (the image of the road and its surroundings, the image of the road sign, etc.) acquired by the image pickup device (not shown) mounted on the vehicle. The amount may be obtained by the arithmetic processing unit 83. As the target turning amount at this time, for example, in addition to the turning radius that the center of the vehicle 1 should pass when the vehicle 1 is turning, the trajectory that the center of the vehicle 1 should pass.

  The travel restriction information in the travel area may be acquired via a communication network such as the Internet, or the travel restriction information transmitted from the information transmission device installed in the travel area may be detected by being mounted on the vehicle 1. A device (not shown) may be used for wireless reception. The arithmetic processing unit 83 automatically switches between the low speed mode and the high speed mode and avoids entering the prohibited area based on the traveling regulation information thus received and the image information of the road sign acquired by the imaging device. It may be carried out on a regular basis. A sidewalk, for example, is an example of the traveling area that should be switched to the low speed mode.

  Further, in the above embodiment, the shaft support member 17 and the shaft support member 21 are directly connected to the vehicle body frame 7, respectively, and in the fifth modification, the rear wheel support member 11 ′ is directly attached to the vehicle body frame 7. An example of binding is shown. However, the present invention is not limited to this, and the shaft support member 17, the shaft support member 21, and the rear wheel support member 11 ′ are attached to the vehicle body frame 7 via a shock absorber provided with an elastic member or a spring member made of a material such as rubber or resin. It may be configured to be supported. When the shaft support member 17 is configured to be supported by the vehicle body frame 7 via such a shock absorber, in the two-step control in the above-described third modification, the front wheel 3 and the front wheel support member 5 are controlled. Not only elastic deformation but also bending of the elastic member of the shock absorber or the spring member will be added. Therefore, the restoration energy for returning the front wheel support member 5 and the front wheels 3 to the original state is increased accordingly, and the front wheels 3 can be steered more quickly.

Further, in the above-described embodiment, in the case of the low speed traveling mode, an example in which the plurality of load sensors 33 are used to obtain the target speed and the target turning amount is shown. However, instead of the load sensor 33, a plurality of simple switches that connect when a predetermined load or more is applied and cut off when no load is applied may be arranged in step 15. Further, as another method, a joystick is attached to the handle post 19 or the handle 35, and the occupant operates the joystick to obtain the target speed and the target turning amount based on the operation amount and the operation direction. Good.
Further, in the embodiment and the fifth modified example, an example in which only one rear wheel 9, 9'is provided is shown, but the invention is not limited to this, and a pair of left and right rear wheels 9, 9'may be provided. .

1 Vehicle 3 Front Wheel 5 Front Wheel Support Member 7 Body Frame (Body)
9 rear wheel 9'rear wheel 11 rear wheel support member 29 electric motor (driving force applying means)
47 Resistance imparting device (steering resistance imparting means)
47 'Resistance imparting device (steering resistance imparting means)
77 Control device (control means)
99 Rotation angle regulation device (rolling direction range changing means)
Lf shaft core (first shaft core)
Lr shaft core (second shaft core)
R Road surface S Virtual straight line

Claims (5)

A pair of left and right front wheels,
At least one rear wheel,
A front wheel support member that rotatably supports each of the front wheels,
A vehicle body that rotatably supports the front wheel support member around a first axis and rotatably supports the rear wheel,
A driving force applying means for individually applying a driving force to each of the front wheels,
The front wheel support member is rotated around the first axis with respect to the vehicle body due to the difference in driving force between the front wheels generated by individually applying the driving force to the front wheels by the driving force applying means. To generate the steering force to move,
In a vehicle in which each of the front wheels is steered by rotating the front wheel support member around the first axis with respect to the vehicle body,
A steering resistance imparting means for imparting resistance against the steering force,
Further comprising control means for controlling the driving force applying means and the steering resistance applying means,
The rear wheel is configured such that the rolling direction can be freely changed in all horizontal directions or within a specified angle range of the horizontal direction,
The control means is configured to control the turning resistance imparting means so as to adjust the resistance force according to the driving condition of the vehicle, and the vehicle travels at a lower speed than when the vehicle travels at a high speed. The vehicle is configured so that the steering resistance applying means is controlled so that the resistance becomes larger when the steering resistance is increased . In the vehicle according to claim 1 ,
The control means is
The steering resistance applying means is controlled so that the resistance is temporarily increased when the front wheels are steered, and the driving force applied to the front wheels is changed from the front wheels inside the steering direction. After controlling the driving force applying means so that the front wheel on the outer side in the rudder direction becomes smaller, subsequently,
The steering resistance applying means is controlled so that the resistance becomes smaller, and the driving force applied to each of the front wheels is made larger in the front wheels on the outer side in the steering direction than on the front wheels on the inner side in the steering direction. A vehicle configured to control the driving force applying means. In the vehicle according to claim 1 or 2 ,
The rear wheel is a single rear wheel, further comprising a rear wheel support member for rotatably supporting the rear wheel,
The rear wheel support member is supported by the vehicle body so as to be rotatable around a second axis,
The first shaft core and the second shaft core are inclined so that the upper portion is located in front of the lower portion,
In the second axle, the intersection point between the virtual straight line extending downward and the traveling road surface when the vehicle is moving forward is the rear wheel from the ground contact point of the rear wheel with the traveling road surface. The vehicle is arranged so as to be located in front of the rolling direction of the vehicle. In the vehicle according to claim 3 ,
Further provided with rolling direction range changing means capable of changing the range of rolling direction in which the rear wheel can point,
A vehicle characterized in that the control means controls the rolling direction range changing means. The vehicle according to claim 4 ,
The control means is configured to control the rolling direction range changing means such that the rolling direction range of the rear wheel becomes narrower when the vehicle travels at high speed than when traveling at low speed. A vehicle characterized by being.

Images