JP2019001200A - Automatic tilting vehicle - Google Patents

Abstract

To provide an automatic tilting vehicle which reduces a support load of a front wheel, which runs onto a step, by shifting the load in a lateral direction along with a tilt of a vehicle, and has thus the performance of the front wheel's overriding a step improved compared with the conventional one.SOLUTION: An automatic tilting vehicle includes: a pair of front wheels spaced each other in a lateral direction; a vehicle tilting apparatus designed to tilt a vehicle by vertically moving the pair of front wheels in mutually opposite directions with respect to a vehicle body; and a control device. The control device estimates a lateral acceleration of the vehicle, calculates a target tilt angle of the vehicle according to the estimated lateral acceleration of the vehicle, and controls the tilt angle of the vehicle so that the tilt angle becomes equal to the target tilt angle. The vehicle is provided with a step switch that is operated by a driver. When the step switch is turned on, the control device controls the tilt angle of the vehicle so that the tilt angle becomes equal to a predesignated tilt angle according to a steering operation amount given by the driver.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an automatically inclined vehicle that automatically leans toward the inside of a turn when turning.

  The automatic tilting vehicle has a vehicle tilting device and is automatically tilted inward by the vehicle tilting device when turning. For example, the following Patent Document 1 discloses an automatic tilt including a pair of front wheels spaced laterally, one rear wheel, a swinging vehicle tilting device, and a control device that controls the vehicle tilting device. The vehicle is listed.

  The vehicle tilting device moves the pair of front wheels, that is, the left and right front wheels up and down in the opposite directions with respect to the vehicle body via the pair of connecting rods by swinging the swing member around the swing axis by the actuator. This inclines the vehicle laterally. The control device estimates, for example, the lateral acceleration of the vehicle based on the steering angle and the vehicle speed, calculates a target tilt angle of the vehicle for turning the vehicle stably based on the estimated lateral acceleration, and Is configured to incline the vehicle so that becomes a target inclination angle.

International Publication No. 2012/049724

[Problems to be Solved by the Invention]
In an automatic tilt vehicle as described in Patent Document 1, in-wheel motors are incorporated in the left and right front wheels, and driving force for traveling is generated by the in-wheel motors. Since in-wheel motors are limited in size to be incorporated into the wheels, the driving force they can generate is also limited. For this reason, even if a normal vehicle using a gasoline engine or the like as a drive source can be stepped on without any problem, an auto-tilt vehicle may not be able to get over.

  The main problem of the present invention is to reduce the support load of the front wheels that ride on the steps by the lateral load movement accompanying the vehicle inclination, thereby improving the ability of the front wheels to get over the steps compared to the conventional automatic tilt Is to provide a vehicle.

[Means for Solving the Problems and Effects of the Invention]
According to the present invention, the vehicle is tilted by moving the pair of front wheels (12L, 12R) spaced apart in the lateral direction and the pair of front wheels up and down in opposite directions with respect to the vehicle body (24). An automatic tilting vehicle (10) including a vehicle tilting device (18) and a control device (20), wherein the control device (20) sets a target tilt angle (θt) for turning the vehicle based on the traveling state of the vehicle. An automatic tilt vehicle is provided that is configured to control the vehicle tilt device (18) so that the vehicle tilt angle (θ) becomes the target tilt angle for turning the vehicle.

  The vehicle is provided with a step switch (62) operated by the driver. When the step switch is on, the control device (20) sets the vehicle inclination angle (θ) to the steering operation amount by the driver. Accordingly, the vehicle tilting device (18) is controlled so as to have a preset target tilt angle (θst) for stepping over a step.

  According to the above configuration, when the step switch is OFF, the target inclination angle for turning the vehicle is calculated based on the traveling state of the vehicle, and the vehicle is set so that the inclination angle of the vehicle becomes the target inclination angle for turning the vehicle. The tilting device is controlled. On the other hand, when the step switch is on, the vehicle tilting device is controlled such that the vehicle tilt angle becomes a target tilt angle for stepping over a preset level according to the amount of steering operation by the driver.

  Therefore, when it is difficult for the front wheels to get over the step with the step switch turned off, the driver switches on the step switch and supports the load on the front wheel that rides on the step by lateral load movement accompanying the inclination of the vehicle. By performing the steering operation so as to decrease the front wheel, it is possible to make it easier for the front wheels to ride on the step. Therefore, compared with the conventional automatic inclination vehicle in which the step switch is not provided and the vehicle inclination angle is controlled so as to become the target inclination angle for turning the vehicle, the performance of the front wheel overcoming the step is improved. Can do.

  In the above description, in order to help understanding of the present invention, the reference numerals used in the embodiment are attached to the configuration of the invention corresponding to the embodiment described later in parentheses. However, each component of the present invention is not limited to the component of the embodiment corresponding to the reference numerals appended in parentheses. Other objects, other features and attendant advantages of the present invention will be readily understood from the description of the embodiments of the present invention described with reference to the following drawings. In the present application, “front-rear direction” and “lateral direction” are the front-rear direction of the vehicle and the lateral direction of the vehicle, respectively, and “front” and “rear” are the front and rear in the front-rear direction of the vehicle, respectively. .

It is a rear view which shows the embodiment of the automatic inclination vehicle by this invention in the state seen from the vehicle rear. It is a side view which shows the state which has the front wheel in the neutral position of a vertical displacement in the state which looked at the automatic inclination vehicle of embodiment from the left side of the vehicle. It is a flowchart which shows the control routine of the inclination angle of the vehicle in embodiment. 7 is a map for calculating a target inclination angle θst of a vehicle when overcoming a step based on a steering angle δ and a vehicle speed V. It is a top view which shows the change of the position of the left-right front wheel when a vehicle inclines to the left. It is a top view which shows the change of the position of a right-and-left front wheel when a vehicle inclines rightward. A side view (A) showing a situation immediately before the vehicle is tilted to the left and the right front wheel climbs on the step, and a side view (B) showing a situation where the vehicle is tilted to the left and the right front wheel starts to climb on the step. It is.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  1 and 2, an automatic tilting vehicle 10 according to an embodiment of the present invention is a three-wheeled vehicle including a pair of front wheels 12L and 12R that are non-steering driving wheels and one rear wheel 14 that is a steering driven wheel. is there. The front wheels 12L and 12R are spaced apart from each other in the lateral direction, and are rotatably supported around the rotation axes 15L and 15R by corresponding wheel carriers 16L and 16R, respectively. The automatic tilting vehicle 10 further includes a vehicle tilting device 18 and an electronic control device 20. The rear wheel 14 may also be a drive wheel, and may be composed of two wheels having a smaller tread than the front wheel.

  In the embodiment, the camber of the front wheels 12L and 12R is a neutral camber, but may be a negative camber or a positive camber. The rear wheel 14 is located rearward with respect to the front wheel and is not shown in the drawing. However, the rear wheel 14 can be displaced vertically with respect to the vehicle body 24 by the rear wheel suspension, and can be displaced and inclined in the lateral direction with respect to the vehicle body 24. Is supported to be limited. Further, the rear wheel 14 is steered in a steer-by-wire manner by the steering device being controlled by the electronic control device 20 in accordance with the amount of operation of the steering wheel 17 by the driver.

  In the illustrated embodiment, although not shown in the drawing, the wheel carriers 16L and 16R incorporate an in-wheel motor as a driving device. The rotation direction and output of the in-wheel motor are controlled by the electronic control unit 20 according to the operation of the shift lever and the accelerator pedal (both not shown) by the driver. Although not shown in the drawing, the braking force of the front wheels 12L, 12R and the rear wheel 14 is controlled by the electronic control device 20 controlling a braking device that operates according to the operation of the brake pedal by the driver. .

  The wheel carriers 16L and 16R are supported by the corresponding suspension arms 22L and 22R so that they can be displaced in the vertical direction with respect to the vehicle body 24, and the lateral displacement and inclination with respect to the vehicle body 24 are restricted. . The suspension arms 22L and 22R shown in the figure are leading arms connected integrally to the wheel carriers 16L and 16R at the front end by a pair of joints 26L and 26R and connected to the vehicle body 24 by joints 28L and 28R at the rear end, respectively. is there.

  The pair of joints 26 </ b> L and 26 </ b> R may be joints such as rubber bushing devices having axes that are spaced apart in the front-rear direction and extend substantially in the vertical direction, for example. The joints 28L and 28R may be joints such as rubber bushing devices having axes 29L and 29R, respectively, extending substantially laterally, for example. The positions of the axes 29L and 29R are the positions of the instantaneous center of the vertical displacement of the front wheels 12L and 12R when viewed in the lateral direction of the vehicle. Note that the suspension arms 22L and 22R may be other arms such as a combination of a trailing arm, an upper arm, and a lower arm as long as the above requirements regarding the wheel carriers 16L and 16R are satisfied.

  The vehicle tilting device 18 includes a swinging member 36 swinging around a swinging axis 34 that slightly tilts backward and extends in the front-rear direction, and an actuator that swings the swinging member 36 around the swinging axis 34. 38 and a pair of connecting rods 40L and 40R. In FIG. 1, for convenience of explanation, the electronic control device 20 is illustrated above the vehicle tilting device 18, but is housed in, for example, an internal structure 41 provided between the front wheels 12 </ b> L and 12 </ b> R. Good.

  The connecting rods 40L and 40R extend substantially vertically on both sides in the transverse direction with respect to the swing axis 34, and can be pivoted to corresponding outer ends of the swing member 36 by joints 42L and 42R at the upper ends, respectively. It is connected. The joints 42L and 42R are preferably joints including pivot pins with rubber bushes having an axis extending substantially in the vehicle longitudinal direction, but may be joints such as ball joints. Although the illustrated connecting rods 40L and 40R are linear, they may be at least partially curved.

  Further, the connecting rods 40L and 40R are pivotally connected to the wheel carriers 16L and 16R by joints 44L and 44R such as ball joints at the lower ends, respectively. The lateral distance between the centers of the joints 44L and 44R is larger than the lateral distance between the centers of the joints 42L and 42R. When a pair of auxiliary arms extending in the vertical direction are provided and the lower ends of these auxiliary arms are fixed to the corresponding suspension arms 22L and 22R, the connecting rods 40L and 40R are the corresponding auxiliary arms. It may be pivotally connected to the upper end of the. In that case, the lower ends of the connecting rods 40L and 40R are integrally connected to the wheel carriers 16L and 16R via the corresponding auxiliary arms and suspension arms 22L and 22R, respectively.

  The swing member 36 includes a boss portion 36B that can rotate around the swing axis 34, and arm portions 36AL and 36AR that are integrated with the boss portion 36B and extend in opposite directions from the boss portion 36B. It functions as a swing arm member that can swing around the movement axis 34. The effective lengths of the arm portions 36AL and 36AR, that is, the distance between the axis 34 and the center of the joint 42L and the distance between the axis 34 and the center of the joint 42R are the same.

  The actuator 38 may be a rotary electric actuator including an electric motor such as a DC brushless motor and a reduction gear device such as a harmonic drive (registered trademark) not shown in the drawing. The output rotation shaft of the actuator 38 protrudes rearward, and a boss portion 36B is fixedly attached to the tip of the output rotation shaft so that the rotational motion of the electric motor is transmitted to the swing member 36 as a swing motion. It has become. The actuator 38 may be a reciprocating or oscillating actuator. In the former case, the reciprocating motion of the actuator is converted into a oscillating motion by a motion converting mechanism and transmitted to the oscillating member 36. It may be like this.

  As shown in FIG. 2, the actuator 38 is disposed between a pair of brackets 46 that are laterally spaced and fixed to the vehicle body 24. The actuator 38 has a pair of pivot shafts 48 that project laterally away from each other, and the pivot shaft 48 is rotatably supported by the bracket 46, so that the actuator 38 is swingably supported around the pivot shaft 48. A shock absorber 50 and a suspension spring (not shown) are interposed between the front end portion of the actuator 38 and the vehicle body 24 below the actuator 38. Therefore, the actuator 38 is limited in displacement and inclination in the lateral direction with respect to the vehicle body, but the shock absorber 50 and the suspension spring are interposed so that the actuator 38 can be displaced in the vertical direction with respect to the vehicle body 24 at the front end portion and the rear end portion. Connected to the car body. The suspension spring may be an elastic member such as a compression coil spring.

  The shock absorber 50 and the suspension spring constitute a front wheel suspension 52 in cooperation with the suspension arms 22L and 22R. The front wheels 12L, 12R and the vehicle tilting device 18 can be relatively displaced in the vertical direction with respect to the vehicle body 24, but are suspended from the vehicle body 24 by the front wheel suspension 52 so that the displacement and the tilt in the lateral direction with respect to the vehicle body are limited. Yes. The relative vertical vibration between the front wheels 12L, 12R and the vehicle body 24 that occurs when the vehicle travels is attenuated by the shock absorber 50, and the impact that the front wheels 12L, 12R are transmitted from the road surface to the receiving vehicle body 24 is shown in the figure. Not relaxed by the suspension spring.

  Although not shown in the drawing, when the swinging member 36 swings around the swing axis 34, the connecting rods 40 </ b> L and 40 </ b> R move up and down in opposite directions, so that the front wheels 12 </ b> L and 12 </ b> R move relative to the vehicle body 24. The vehicle 10 moves up and down in opposite directions, whereby the vehicle 10 tilts in the lateral direction. In particular, the swing member 36 swings so that the connecting rod on the inside of the turn rises and the connecting rod on the outside of the turn descends, whereby the vehicle 10 tilts inward of the turn.

  When the front wheels 12L and 12R move up and down, they rotate around the axes 29L and 29R of the joints 28L and 28R, respectively. Therefore, the rotation axes 15L and 15R of the front wheels 12L and 12R are shown by a one-dot chain line 64 in FIG. Draw the indicated trajectory. When the front wheels 12L and 12R move upward, the front wheels 12L and 12R are displaced backward with respect to the neutral position shown in FIG. 2, and conversely, when the front wheels 12L and 12R move downward, they move forward with respect to the neutral position shown in FIG. Displace to

  The inclination angle θ of the vehicle 10 is detected by an inclination angle sensor 56 such as a gyroscope, and a signal indicating the inclination angle θ of the vehicle is input to the electronic control unit 20. The tilt angle θ is 0 when the swing angle of the swing member 36 is 0 and the center plane 30 coincides with the vertical direction, and is a positive value when the vehicle 10 tilts leftward. Further, since the tilt angle θ of the vehicle 10 is substantially the same as the roll angle (not shown) of the vehicle body 24, the roll angle of the vehicle body may be detected as the tilt angle θ of the vehicle 10 by the roll angle sensor. .

  The motor 46 of the actuator 38 is provided with a rotation angle sensor 58 such as a rotary encoder that detects the rotation angle φ of the motor, and a signal indicating the rotation angle φ is input to the electronic control unit 20. The rotation angle φ detected by the rotation angle sensor 58 becomes 0 when the swing angle of the swing member 36 is 0, and the swing member 36 swings so that the vehicle 10 tilts to the left. Becomes a positive value.

  The vehicle 10 is provided with a steering angle sensor 60 and a step switch 62 operated by a driver. A signal indicating the steering angle δ detected by the steering angle sensor 60 and a signal indicating whether or not the step switch 62 is on are input to the electronic control unit 20. Although not shown in FIG. 1, a signal indicating the accelerator position is input from the accelerator position sensor to the electronic control unit 20, and a signal indicating the shift position is input from the shift position sensor. Further, the electronic control unit 20 receives a signal indicating a pedaling force with respect to a brake pedal (not shown) from a pedaling force sensor and a signal indicating a vehicle speed V from a vehicle speed sensor.

  The inclination angle of the vehicle 10 is controlled by controlling the actuator 38 of the vehicle inclination device 18 by the electronic control device 20. When the vehicle 10 normally travels, the electronic control unit 20 calculates the estimated lateral acceleration Gyh of the vehicle based on the steering angle δ and the vehicle speed V, and sets the target inclination angle θt for turning of the vehicle 10 based on the estimated lateral acceleration. Calculate. The electronic control unit 20 calculates the target rotation angle φt of the electric motor of the actuator 38 based on the target inclination angle θt, and controls the electric motor so that the rotation angle φ of the electric motor becomes the target rotation angle. Further, the electronic control unit 20 calculates the target turning angle of the rear wheel 14 based on the steering angle δ and the vehicle speed V, and is shown in the figure so that the turning angle of the rear wheel becomes the target turning angle. By controlling the non-steering actuator, the rear wheel 14 is steered in a steer-by-wire manner.

  When the vehicle 10 gets over the step, the driver operates the step switch 62 as necessary. When the step switch 62 is on, the electronic control unit 20 calculates a target inclination angle θst for stepping over the step of the vehicle 10 based on the steering angle δ and the vehicle speed V, unlike during normal driving. Further, the electronic control unit 20 calculates the target rotation angle φst of the electric motor of the actuator 38 based on the target inclination angle θst, and controls the electric motor so that the rotation angle φ of the electric motor becomes the target rotation angle φst.

  The electronic control device 20 may include, for example, a microcomputer having a CPU, a ROM, a RAM, and an input / output port device, which are connected to each other via a bidirectional common bus. The electronic control unit 20 controls the inclination angle of the vehicle 10 according to the flowchart shown in FIG. A control program corresponding to the flowchart shown in FIG. 3 is stored in the ROM, and the inclination angle of the vehicle 10 is controlled by the CPU according to the control program.

  Next, the control of the tilt angle of the vehicle 10 will be described with reference to the flowchart shown in FIG. The control according to the flowchart shown in FIG. 3 is repeatedly executed at predetermined time intervals when an ignition switch (not shown) is on.

  First, in step 10, a signal indicating the inclination angle θ of the vehicle 10 detected by the inclination angle sensor 56 is read.

  In step 20, it is determined whether or not the step switch 62 is on, that is, whether or not the driver desires control of the vehicle inclination angle to get over the step. When an affirmative determination is made, the control of the tilt angle proceeds to step 40, and when a negative determination is made, the control of the tilt angle proceeds to step 30.

  In step 30, the inclination angle θ during normal traveling of the vehicle 10 is controlled. That is, the estimated lateral acceleration Gyh of the vehicle is calculated based on the steering angle δ and the vehicle speed V, the target inclination angle θt for turning of the vehicle 10 is calculated based on the estimated lateral acceleration, and the actuator 38 is operated based on the target inclination angle. The target rotation angle of the electric motor is calculated, and the electric motor is controlled so that the rotation angle of the electric motor becomes the target rotation angle. Note that the control of the inclination angle θ during normal traveling of the vehicle does not form the gist of the present invention, and may be performed in any manner known in the art.

  In step 40, a map indicated by a solid line in FIG. 4 is referred to based on the steering angle δ and the vehicle speed V, thereby calculating the target inclination angle θst for stepping over the vehicle. As shown in FIG. 4, the target inclination angle θst is 0 when the absolute value of the steering angle δ is equal to or smaller than the first reference value δ1 (positive constant), and the absolute value of the steering angle δ is the first value. When the second reference value Δ2 is greater than the first reference value Δ1, it is a positive constant maximum value. When the absolute value of the steering angle δ is a value between the first reference value δ1 and the second reference value δ2, the target inclination angle θst increases as the absolute value of the steering angle δ increases.

  As shown in FIGS. 1, 5, and 6, the center of gravity 66 of the vehicle 10 is located in the center plane 30 of the vehicle slightly behind the front wheels 12 </ b> L and 12 </ b> R and in front of the rear wheels 14. In order to prevent the vehicle 10 from overturning even when the vehicle 10 is tilted, the legs of the perpendicular line dropped from the center of gravity of the vehicle to the road surface are positioned inside the triangle 68 connecting the grounding points Pfl, Pfr and Pr of the front wheels 12L and 12R and the rear wheel 14. Must be. The maximum value of the target inclination angle θst is set in order to limit the inclination angle of the vehicle so that the perpendicular foot does not go out of the triangle 68 when the inclination angle of the vehicle is controlled. The higher the vehicle speed V, the easier it is for the vehicle inclination angle to increase due to the reaction force of the front wheels striking the step, so the absolute value of the maximum value of the target inclination angle θst and the second reference value δ2 Is smaller as the vehicle speed V is higher.

  In step 50, the target swing angle φst of the swing member 36 for calculating the deviation θ−θst between the tilt angle θ of the vehicle 10 and the target tilt angle θst to 0 is calculated.

  In step 60, the target rotation angle φmt of the motor of the actuator 38 for achieving the target swing angle φst is calculated. Further, the motor is controlled so that the rotation angle φm of the motor becomes the target rotation angle φmt, so that the swing angle φ of the swing member 36 is controlled to become the target swing angle φst. The angle θ is controlled to be the target inclination angle θst for stepping over the step.

  As can be seen from the above description, when the step switch 62 is off and the driver does not want to control the vehicle tilt angle to get over the step, a negative determination is made in step 20, so in step 30 the vehicle 10 is controlled for the inclination angle θ during normal running. Therefore, the vehicle 10 can be tilted inwardly to turn the vehicle stably.

  On the other hand, when the step switch 62 is on and the driver desires control of the vehicle tilt angle to get over the step, an affirmative determination is made in step 20, so steps 40 to 60 are executed. . That is, in step 40, the target inclination angle θst for stepping over the step is calculated so that the steering angle δ increases as the absolute value of the steering angle δ increases and decreases as the vehicle speed V increases. In steps 50 and 60, The actuator 38 is controlled so that the inclination angle θ of the vehicle 10 becomes the target inclination angle θst.

  When the steering wheel 17 is steered leftward and the vehicle 10 is tilted to the left, as shown in FIG. 5, the left front wheel 12L moves upward and the right front wheel 12R moves downward. Therefore, the right front wheel 12R is positioned in front of the left front wheel 12L. Further, the vehicle 10 turns left as indicated by the solid arrow by turning the rear wheel 14, and the vehicle tilts leftward with respect to the step 70. Therefore, this also makes the right front wheel 12R closer to the step 70 than the left front wheel 12L. Since the center of gravity 66 of the vehicle is positioned on the left side of the vehicle center plane 30 'on the road surface as indicated by the dashed arrow, the support load Wfr of the right front wheel 12R is reduced and the support of the left front wheel 12L is supported. The load Wfl is increased.

  Conversely, when the steering wheel 17 is steered in the right turn direction and the vehicle 10 is tilted to the right, the left front wheel 12L moves downward and the right front wheel 12R moves as shown in FIG. Since it moves upward, the left front wheel 12L is positioned in front of the right front wheel 12R. Further, the vehicle 10 turns right as indicated by the solid arrow by turning the rear wheel 14, and the vehicle tilts to the right with respect to the step 70. Therefore, this also makes the left front wheel 12L closer to the step 70 than the right front wheel 12R. Since the center of gravity 66 of the vehicle is located to the right of the vehicle center plane 30 'on the road surface, the support load Wfl of the left front wheel 12L is reduced and the support load Wfr of the right front wheel 12R is increased.

  The target inclination angle θst of the vehicle 10 increases as the absolute value of the steering angle δ increases. Therefore, the amount of displacement in the front-rear direction of the left and right front wheels and the amount of change in the support load of the left and right front wheels accompanying the inclination of the vehicle 10 increases as the absolute value of the steering angle δ increases. Further, the target inclination angle θst of the vehicle 10 is larger as the vehicle speed V is lower. Therefore, the amount of displacement in the front-rear direction of the left and right front wheels and the amount of change in the support load of the left and right front wheels accompanying the inclination of the vehicle 10 increases as the vehicle speed V decreases.

  As shown in FIG. 7A, in the situation before the right front wheel 12R rides on the step 70, the driving force Ffrr is applied to the right front wheel 12R as a reaction force from the road surface 72 of the driving force Ffr of the right front wheel 12R. Works. However, as shown in FIG. 7B, when the right front wheel 12R rides on the step 70 and leaves the road surface 72, the driving force Ffrr as a reaction force from the road surface 72 does not act on the right front wheel 12R. The driving force Ffr of the right front wheel 12R acts on the corner portion P of the step 70, and the right front wheel 12R receives a reaction force Ffrr from the corner portion P.

  In order for the right front wheel 12R to ride on the step 70, the right front wheel 12R must rotate around the corner P in the clockwise direction as seen in FIG. The reaction force Ffrr cannot generate a torque that rotates the right front wheel 12R around the corner portion P. Therefore, the torque required by the reaction force Fflr of the driving force Ffl of the left front wheel 12L acting on the rotation axis 15R of the right front wheel 12R. Must be generated. In order to generate the necessary torque, the clockwise torque around the corner portion P due to the reaction force Fflr becomes the counterclockwise torque caused by the support load Wfr acting on the rotation axis 15R of the right front wheel 12R. You must overcome it.

Therefore, the following formula (1) must be established. Similarly, in order for the left front wheel 12L to ride on the step 70, the following equation (2) must be established. In the following formulas (1) and (2), R is the radius of the right front wheel 12R and the left front wheel 12L, and H is the height of the step 70 with respect to the road surface 72. The angle α is an angle formed by a line segment connecting the rotation axis of the wheel and the corner portion P of the step 70 with respect to the vertical direction.
Fflr> (Wfr · R · sinα) / (R−H) (1)
Ffrr> (Wfl · R · sinα) / (R−H) (2)

  From formulas (1) and (2), it can be seen that the driving force of the opposite left and right front wheels required for one of the left and right front wheels to climb on the step is smaller as the supporting load of the wheel riding on the step is lower. Therefore, in order to drive one of the left and right front wheels on the step in a situation where the driving force of the left and right front wheels is limited, it is useful to reduce the support load of the wheel. In a situation where one of the left and right front wheels rides on a step, the driving force of the opposite left and right front wheels is reversed until the one front wheel has substantially completed the step and can be advanced by its own driving force. It is preferable that a force acts as a driving force on the one front wheel. For this purpose, it is preferable that the front wheel opposite to the one front wheel is positioned as far as possible in the traveling direction with respect to the one front wheel.

  According to the embodiment, the target inclination angle θst of the vehicle over the step is calculated based on the steering angle δ and the vehicle speed V, and the actuator 38 is controlled so that the inclination angle θ of the vehicle 10 becomes the target inclination angle θst. . The front left and right wheels are moved in the front-rear direction so that the front wheels on the inclined side are positioned behind the front wheels opposite to the left and right. The supporting load of the front wheel to be reduced is reduced. Further, the vehicle turns in the same direction as the tilted direction, and the difference in the distance between the left and right front wheels up to the step 70 is increased.

  Therefore, the vehicle can easily get over the step as compared with the case where the control of the inclination angle of the vehicle when stepping over the step is not performed. Further, when the driver cannot get over the step by the normal traveling of the vehicle 10, the driver only has to switch on the step switch 62 and perform the necessary steering operation.

  When the preceding wheel of the left and right front wheels rides on a step, the reaction force of the driving force of the preceding wheel is given as a driving force to the opposite wheel when the wheel opposite to the left and right wheels climbs the step. It is done. Also, if the steering angle is reduced to, for example, 0 after the preceding wheel has climbed the step, or if the steering direction is reversed, the difference in the position of the left and right front wheels in the front-rear direction decreases, Moved to approach the preceding wheel. In this case, if the steering direction is reversed, the support load of the delayed wheel decreases, and the wheel easily climbs on the step. Therefore, it is preferable that the steering direction is reversed after the preceding wheel rides on the step. .

  In addition, according to the embodiment, the target inclination angle θst of the vehicle when stepping over a step is calculated to be larger as the absolute value of the steering angle δ is larger. Therefore, the amount of displacement in the front-rear direction of the left and right front wheels and the amount of change in the support load of the left and right front wheels accompanying the inclination of the vehicle 10 increases as the absolute value of the steering angle δ increases. Accordingly, the driver determines the height of the step by visual inspection, and controls the steering angle δ by the steering operation according to the determination result, thereby determining the amount of displacement in the front-rear direction of the left and right front wheels and the left and right according to the height of the step. The amount of change in the support load of the front wheels can be appropriately controlled.

  Furthermore, according to the embodiment, the target inclination angle θst of the vehicle 10 is calculated to be smaller as the vehicle speed V is higher. Therefore, the amount of displacement in the front-rear direction of the left and right front wheels and the amount of change in the support load of the left and right front wheels accompanying the inclination of the vehicle 10 is smaller as the vehicle speed V is higher. Therefore, when the vehicle speed V is low, the amount of displacement in the front-rear direction of the left and right front wheels and the amount of change in the support load of the left and right front wheels can be increased to make it easier for the vehicle to get over the step. Conversely, when the vehicle speed V is high, the amount of displacement in the front-rear direction of the left and right front wheels and the amount of change in the support load of the left and right front wheels are reduced, resulting from the impact load that the preceding front wheels receive from the step when the vehicle passes over the step. The possibility that the vehicle inclination angle becomes excessive can be reduced.

  Although the present invention has been described in detail with respect to specific embodiments, the present invention is not limited to the above-described embodiments, and various other embodiments are possible within the scope of the present invention. This will be apparent to those skilled in the art.

  For example, in the above-described embodiment, the vehicle tilting device 18 has the swinging member 36 swung around the swinging axis 34, and the swinging of the swinging member 36 is caused by the pair of connecting rods 40L and 40R. It is transmitted to 12L and 12R. However, the vehicle tilting device may have any configuration known in the art as long as the left and right front wheels can be moved up and down with respect to the vehicle body 24 in opposite phases.

  In the above-described embodiment, the absolute value of the maximum value of the target inclination angle θst and the second reference value δ2 are smaller as the vehicle speed V is higher, but the absolute value of the maximum value of the target inclination angle θst and the second reference value At least one of the values δ2 may be a constant value regardless of the vehicle speed V. Further, the target inclination angle θst of the vehicle 10 is variably set according to the vehicle speed V so as to decrease as the vehicle speed V increases. However, regardless of the vehicle speed V, the target inclination angle θst may be modified so as to be variably set according to the absolute value of the steering angle δ so as to increase as the absolute value of the steering angle δ increases.

  In the above-described embodiment, the axes 29L and 29R, which are the instantaneous centers of the left and right front wheels 12L and 12R, are rearward and downward with respect to the rotation axes 15L and 15R when the front wheels 12L and 12R are in the neutral position, respectively. However, the instantaneous centers of the left and right front wheels 12L and 12R may be forward and upward with respect to the rotation axes 15L and 15R when the front wheels are in the neutral position. Also in this case, the front wheels 12L and 12R are displaced backward with respect to the neutral position when moving upward, and are displaced forward with respect to the neutral position when moving downward.

  In the embodiment described above, the target inclination angle θst for stepping over the step of the vehicle is calculated by referring to the map indicated by the solid line in FIG. 4 based on the steering angle δ and the vehicle speed V. However, when the preceding wheel rides on the step, the vehicle tilts due to the difference in the height of the ground contact surfaces of the left and right front wheels. Therefore, it is preferable that the support load of the delayed wheel is effectively reduced by tilting the vehicle toward the preceding wheel when the delayed wheel rides on the step. Accordingly, when the steering direction is reversed after the preceding wheel has stepped on the step, the target inclination angle θst for stepping over the step has a large absolute value by referring to the map indicated by the broken line in FIG. It may be modified so as to be calculated into a value.

  Furthermore, in the above-described embodiment, even when the step switch 60 is on, the rear wheel steering transmission ratio is the same as when the step switch 60 is off, that is, when the vehicle 10 is traveling normally. However, when the front wheels pass over the steps, the vehicle is tilted so that the positions of the left and right front wheels are shifted in the front-rear direction, and the support load of the front wheels located on the front side is reduced. The vehicle may not be steered at the steering transmission ratio during normal traveling of the vehicle. Therefore, when the step switch 60 is on, the steering transmission ratio of the rear wheels may be lowered compared to when the step switch 60 is off.

  Further, for example, a dial-type or slider-type operation device operated by a driver may be modified so that the steering transmission ratio of the rear wheels can be variably set when the step switch 60 is on. In this case, the settable rear wheel steering transmission ratio may include a reverse phase steering region.

  For example, when the front-rear direction of the vehicle is inclined with respect to the step, the vehicle is inclined such that the wheel far from the step is raised with respect to the vehicle body, so that the turning angle of the vehicle in the front-rear direction with respect to the step is reduced by turning. The rear wheels are steered so that Therefore, depending on the situation, the inclination angle of the front wheel on the front side with respect to the step becomes small, and the lateral force that the wheel receives from the step becomes large, and it may be difficult to get on the step. In such a situation, if the steering transmission ratio of the rear wheels is set to the value of reverse phase steering, the inclination angle of the front wheels on the front side with respect to the step can be increased, and the lateral force that the wheel receives from the step can be reduced. it can.

DESCRIPTION OF SYMBOLS 10 ... Auto-tilt vehicle, 12L, 12R ... Front wheel, 16L, 16R ... Wheel carrier, 18 ... Vehicle tilting device, 20 ... Electronic control unit, 24 ... Vehicle body, 34 ... Swing axis, 36 ... Swing member, 38 ... Actuator 40L, 40R ... connecting rod, 56 ... tilt angle sensor, 58 ... rotation angle sensor, 60 ... steer angle sensor, 62 ... step switch

Claims (1)

An auto-tilt vehicle including a pair of front wheels spaced apart in the lateral direction, a vehicle tilting device configured to tilt the vehicle by moving the pair of front wheels up and down in opposite directions with respect to the vehicle body, and a control device The control device calculates a target inclination angle for turning the vehicle based on a traveling state of the vehicle, and controls the vehicle inclination device so that the inclination angle of the vehicle becomes the target inclination angle for turning the vehicle. In an auto-tilt vehicle configured as follows:
The vehicle is provided with a step switch that is operated by a driver, and the control device is configured such that when the step switch is on, a step in which the inclination angle of the vehicle is preset according to the amount of steering operation by the driver. An automatic tilting vehicle configured to control the vehicle tilting device so as to have a target tilt angle for passing over.

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