Tilting vehicle

Abstract

A tilting vehicle (10) has: a plurality of wheel units (16) provided at least at a front and a rear position of a vehicle body (12), each having a pair of wheels (14) spaced apart in one direction of the vehicle width; a tilting unit provided near one of the wheel units, having a tilting mechanism configured to tilt the wheel unit and the vehicle body relative to a ground in an inward direction, and a tilting drive unit configured to drive the tilting mechanism; and a passive suspension (54) provided at the other of the wheel units, configured to produce roll stiffness when the vehicle body is tilted relative to the ground in the vehicle width direction.

Description

TECHNICAL AREA

[0001] This disclosure relates to a lean vehicle. DISCUSSION OF THE BACKGROUND

[0002] In the prior art, various motorized vehicles for small passenger groups, such as small single-person vehicles, have practical use as simple transportation. In the case of such small passenger group vehicles, miniaturization is implemented by reducing the length of the vehicle in a forward-backward direction and by reducing the vehicle width. On the other hand, reducing the vehicle width tends to make it difficult to maintain vehicle stability. For example, at the time of a vehicle turn, a centrifugal force generated in an outward direction may cause the vehicle attitude to become unstable.Therefore, a tilting vehicle having a tilting mechanism capable of balancing the centrifugal force generated in an outward direction at the time of the vehicle turning operation and improving the stability of the vehicle attitude by relatively tilting a vehicle body and a road surface (wheels in contact with the ground) in a width direction of the vehicle (inward direction / inward direction) depending on the driving conditions has been proposed.

[0003] Examples of the relevant prior art can be found in JP 2021 - 160 610 A.

[0004] In order to further popularize the tilting vehicle as described above, it is desirable to provide a simple structure in which the stable driving performance can be maintained and a stable tilting posture at the time of turning can be implemented, as well as a configuration that easily realizes cost reduction.

[0005] Therefore, there is a need for a tilting vehicle having a simple structure in which stable driving performance can be maintained and a stable tilting attitude at the time of turning can be implemented, and which enables cost reduction in a simple manner. SUMMARY

[0006] According to one aspect of this disclosure, a tilting vehicle, as an example disclosed herein, includes: a plurality of wheel units provided at least at a front position and a rear position of a vehicle body, each having a pair of wheels spaced apart from each other in a vehicle width direction; a tilting unit provided in a vicinity of one of the wheel units, and having a tilting mechanism configured to relatively tilt the wheel unit and the vehicle body with respect to a ground in an inward direction, and a tilting drive unit configured to drive the tilting mechanism; and a passive suspension provided at the other of the wheel units and configured to generate roll rigidity when the vehicle body is tilted with respect to the ground in the vehicle width direction.

[0007] According to the configuration described above, for example, the tilting unit is provided in one of the wheel units at least at the front position and the rear position of the vehicle body, and the passive suspension is provided in the other of the wheel units. Therefore, it is possible to provide a tilting vehicle having a simple structure in which the roll stabilization by the roll rigidity of the passive suspension and the tilt control by the tilting unit can be performed in a balanced manner, the stable driving performance can be maintained, and the more stable tilt posture can be implemented at the time of turning, and which has a configuration that easily realizes cost reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The foregoing and additional features and characteristics of this disclosure will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which: Fig. 1 is an exemplary and schematic side view illustrating a configuration of a tilting vehicle according to an embodiment; Fig. 2 is an exemplary and schematic pictorial view illustrating a state in which the tilting vehicle is not tilted in a vehicle width direction when the tilting vehicle according to the embodiment is viewed from a rear side; Fig. 3 is an exemplary and schematic pictorial view illustrating a state in which the tilting vehicle is tilted in the vehicle width direction (in an inward direction) when the tilting vehicle according to the embodiment is viewed from the rear; Fig. 4 is an exemplary and schematic perspective view illustrating a configuration of a passive suspension provided on front wheels of the tilting vehicle according to the embodiment; Fig. 5 is an exemplary and schematic pictorial view illustrating a state in which the tilting vehicle is not tilted in the vehicle width direction when the tilting vehicle according to the embodiment is viewed from a front side; Fig. 6 is an exemplary and schematic pictorial view illustrating a state in which the tilting vehicle is tilted (turning inward) in the vehicle width direction when the tilting vehicle according to the embodiment is viewed from the front side; and Fig. 7 is an exemplary and schematic block diagram illustrating a configuration of a control device that performs tilt control in the tilting vehicle according to the embodiment. DETAILED DESCRIPTION

[0009] Hereinafter, an embodiment and a modification disclosed herein will be described with reference to the drawings. The configurations of the embodiment and the modification described later, as well as the functions and effects achieved by the configurations, are merely examples and are not limited to the following description.

[0010] Fig. 1 is an exemplary and schematic side view illustrating a configuration of a tilting vehicle 10 according to the embodiment. In the tilting vehicle 10 according to the present embodiment, a tilting unit is arranged on at least one wheel unit at a front position and a rear position of a vehicle body, and a passive suspension capable of generating roll rigidity is arranged on the other wheel unit. According to this configuration, compared with a vehicle having tilting units on the front and rear wheels, cost reduction of the tilting vehicle 10 can be realized, stable driving performance can be maintained, and, in particular, driving stability during turning can be achieved.

[0011] Fig. 1 shows a state in which the tilting vehicle 10 is provided on a horizontal ground GL and is not tilted. Fig. 1 shows a front direction DF, a rear direction DB, an upward direction DU, a downward direction DD, a right direction DR, and a left direction DL. The front direction DF is a front direction (i.e., a forward direction) of the tilting vehicle 10, and the rear direction DB is a direction opposite to the front direction DF. The upward direction DU is a vertically upward direction, and the downward direction DD is a vertically downward direction (i.e., a direction opposite to the upward direction DU). The vertically downward direction is a direction of gravity. The right direction DR is a right direction viewed from the tilting vehicle 10 traveling in the front direction DF, and the left direction DL is a direction opposite to the right direction DR.Both the front direction DF and the rear direction DB, the right direction DR, and the left direction DL are horizontal directions. For example, the upward direction DU and the downward direction DD are perpendicular to the front direction DF.

[0012] The tilting vehicle 10 according to the present embodiment is, for example, a small vehicle for one person. The tilting vehicle 10 has a plurality of wheel units 16 (a rear wheel unit 16R and a front wheel unit 16F) provided at least at a front position and a rear position of a vehicle body 12, each having a pair of wheels 14 spaced apart from each other in a vehicle width direction (the right direction DR and the left direction DL). That is, the tilting vehicle 10 according to the present embodiment is a four-wheel vehicle. Fig. 1 is a view of the tilting vehicle 10 as seen from a right side surface, and the front and rear wheels 14 on the right side are omitted for simplicity of description of the structure.

[0013] The tilting vehicle 10, which consists of Fig. 1, for example, the rear wheel unit 16R is a unit for driving wheels. The driving wheels (rear wheel wheels 14) can be rotated, for example, by a power transmission mechanism using a drive motor or a reduction mechanism, or by an in-wheel motor built into each wheel 14. In contrast, the front wheel unit 16F is a non-driving wheel and a rotating wheel rotatable in the width direction (i.e., in the right direction DR and the left direction DL) of the tilting vehicle 10. A traveling direction of the rotating wheel is rotatable to the right or left from the front direction DF. In another embodiment, the rear wheel unit 16R may consist of non-driving wheels, and the front wheel unit 16F may consist of driven wheels rotatable in a left-to-right direction.It is sufficient for the tilting vehicle 10 to include the wheel unit 16 with the pair of wheels 14 that are spaced apart from each other in the width direction of the vehicle at least at the front and rear positions. For example, the tilting vehicle 10 may have six or more wheels.

[0014] The vehicle body 12 includes a body portion 12a. The body portion 12a includes a lower portion 12b, a front wall portion 12c connected to a front direction DF side of the lower portion 12b, a front portion 12d extending from an upper end of the front wall portion 12c toward the forward direction DF, a rear wall portion 12e connected to a rearward direction DB side of the floor portion 12b, and a rear portion 12f extending from an upper end of the rear wall portion 12e toward the rearward direction DB.

[0015] The vehicle body 12 further includes a seat 18 fixed to the lower portion 12b, an accelerator pedal 20 and a brake pedal 22 provided on one side of the seat 18 in the front direction DF, a control device 24 fixed to the lower portion 12b, and a steering wheel 26 attached to the front portion 12d. Although not shown, another member (for example, a roof or a headlight) may be fixed to the body portion 12a.

[0016] The seat 18 has a seat bottom portion 18a and a backrest portion 18b so that a driver can adjust the operation of the accelerator pedal 20 and the brake pedal 22 by pressing and can operate the steering wheel 26 while in a sitting posture.

[0017] The accelerator pedal 20 adjusts an output state of a drive motor that rotates the drive wheels (the wheels 14 for the rear wheels) by adjusting an operation amount operated by the driver. The brake pedal 22 adjusts a braking state caused by a mechanical brake provided to the wheels 14 by adjusting an operation amount operated by the driver.

[0018] The steering wheel 26 is a member rotatable in the right and left directions. A rotation angle (also referred to as an input angle) of the steering wheel 26 with respect to a predetermined rotation position indicating straight-ahead travel (also referred to as a straight-ahead travel rotation position) is an example of target turning information indicating a target turning direction and a target turning degree. In the present embodiment, "input angle = zero" means straight-ahead travel, "input angle > zero" means right-turning, and "input angle < zero" means left-turning. A magnitude (i.e., an absolute value) of the input angle indicates the target turning degree. The driver can input the target turning information by operating the steering wheel 26.The connection between the steering wheel 26 and a steering mechanism that steers the wheels 14 on a front wheel side can be implemented by a mechanical steering mechanism that is mechanically connected or by a cable steering that is electrically connected.

[0019] A direction sensor 28 is attached to a part of the vehicle body 12, for example, the rear portion 12e. The direction sensor 28 is a sensor that measures a roll angle and a yaw angular velocity of the vehicle body 12. The direction sensor 28 includes an acceleration sensor 30, a gyro sensor 32, and a control unit 34. The acceleration sensor 30 is a sensor that detects accelerations in any direction and is, for example, a three-axis acceleration sensor. The direction of the acceleration detected by the acceleration sensor 30 is referred to as the detection direction. In a state where the tilting vehicle 10 is stopped, the detection direction is the same as the vertically downward direction DD. The gyro sensor 32 is a sensor that detects an angular velocity around a rotation axis in any direction and is, for example, a three-axis angular velocity sensor.The control unit 34 indicates the roll angle and yaw rate using a signal from the acceleration sensor 30, a signal from the gyro sensor 32, and, for example, a signal from a speed sensor 36 provided in the front wheel unit 16F. The control device 34 is, for example, a data processing device including a computer. These sensors implement an inertial measurement unit (IMU) and can acquire a current tilt state (current tilt angle) of the tilting vehicle 10 while traveling.

[0020] First, the rear wheel unit 16R mounted on the tilting vehicle 10 is described.

[0021] As from Fig. 1, the rear wheel unit 16R, which is arranged on a side of the rear portion 12e of the tilting vehicle 10 arranged in the rear direction with respect to the vehicle body 12, comprises a rear connecting device 38A which connects the wheels 14 on a rear wheel side to the vehicle body 12. An example is shown in which the tilting vehicle 10 is made of Fig. 1, the wheels 14 on the rear wheel side are rotated by a power transmission mechanism such as a drive motor 40 and a reduction mechanism 42. The rear wheel unit 16R has a battery 44 that supplies power to the drive motor 40, a tilt motor (a tilt drive unit for driving a tilt mechanism) of a tilt unit, which will be described later, and various devices that

[0022] are installed in the tilting vehicle 10. Therefore, a weight of the vehicle body 12 of the tilting vehicle 10 according to the present embodiment is distributed more to the rear wheel unit 16R side with the tilting unit than to the front wheel unit 16F side (a side on which the suspension is installed will be described later) without the tilting unit. Thereby, more torque of the tilting motor generated by the tilting unit can be transmitted to a road surface (the ground GL), and the posture control performance by the tilting unit can be improved. The drive motor 40 is rotationally controlled according to the operation degree of the accelerator pedal 20 and drives the wheels 14 on the rear wheel side via the reduction mechanism 42. The power transmission mechanism using the drive motor 40 and the reduction mechanism 42, the battery 44, and the like may employ a known configuration, and a detailed description will be omitted.

[0023] The rear wheel unit 16R and the vehicle body 12 are connected by a rear connecting rod 46A. In the rear connecting rod 46A, an end portion 46Aa on the vehicle body 12 side is pivotally connected to the vehicle body 12, and an end portion 46Ab on the rear wheel unit 16R side is fixed to the rear wheel unit 16R. A rear spring member 48 serving as a suspension is disposed between a central portion of the rear connecting rod 46A and the vehicle body 12. As a result, the rear wheel unit 16R (the wheels 14, which are the rear wheels) and the vehicle body 12 can move (pivot) with respect to each other in an up / down direction.For example, when the vehicle travels on uneven ground GL, the rear wheel unit 16R shifts mainly in the up / down direction, thereby reducing the transmission of vibrations in the up / down direction to the vehicle body 12 side. In the configuration of . Fig. 1, there is only one rear spring member 48 at a substantially central portion in the width direction of the vehicle, and the rear spring member 48 has no roll rigidity. Therefore, the rear wheel unit 16R of the tilting vehicle 10 according to the present embodiment does not have a configuration in which roll rigidity is generated by a spring member. The front wheel unit 16F (a front link mechanism 38B to be described later) and the vehicle body 12 are connected by a front link rod 46B. In the front link rod 46B, an end portion 46Ba on the vehicle body 12 side is fixed to the vehicle body 12, and an end portion 46Bb on the front wheel unit 16F side is fixed to the front wheel unit 16F.

[0024] Fig. 2 is an exemplary schematic diagram illustrating a state in which the tilting vehicle 10 is not tilted in the vehicle width direction when the tilting vehicle 10 is viewed from a rear side. Fig. 3 is an exemplary and schematic pictorial view illustrating a state in which the tilting vehicle 10 is tilted in the vehicle width direction (an inward direction) when the tilting vehicle 10 is viewed from the rear. Fig. 2 and Fig. 3, the power transmission mechanism, such as the drive motor 40 and the speed reduction mechanism 42 of the rear linkage 38A, is not shown to facilitate understanding of the behavior of the tilting vehicle 10.

[0025] As described above, two of the wheels 14 (rear wheels) and the vehicle body 12 are connected by the rear linkage 38A. The rear linkage 38A includes the tilting device. The tilting device includes a rear linkage 50 serving as a tilting mechanism (a mechanism that tilts the tilting vehicle 10 in the inward direction) and a tilting motor 52 serving as a tilting drive unit, which is mounted on the rear linkage 50.

[0026] The rear link mechanism 50 is a so-called parallel link and has a function of relatively tilting the rear wheel unit 16R (wheel unit) and the vehicle body 12 with respect to the ground in the inward direction. The rear link 50 has three vertical link parts 50a, 50b, and 50c arranged in the right direction DR, and two lateral link parts 50d and 50e arranged downward in the direction DD. As shown in Fig. As shown in Figure 2, when the tilting vehicle 10 is upright without being tilted on the horizontal ground GL (i.e., the ground GL is perpendicular to the vertical direction DU) (a posture SR1), the vertical connecting parts 50a, 50b, and 50c are parallel to the vertical direction, and the side connecting parts 50d and 50e are parallel to the horizontal direction. The two vertical connecting parts 50a and 50c and the two side connecting parts 50d and 50e form a parallel quadrilateral connecting mechanism. The vertical connecting part 50b connects central portions of the two side connecting parts 50d and 50e. The vertical connecting parts 50a, 50b, and 50c and the side connecting parts 50d and 50e are formed of, for example, metal.

[0027] The rear link mechanism 50 has bearings that rotatably connect a plurality of link parts. For example, a bearing 54a rotatably connects the vertical link part 50b and the lateral link part 50e. A bearing 54b rotatably connects the vertical link part 50a and the lateral link part 50e. A bearing 54c rotatably connects the vertical link part 50c and the lateral link part 50e. Other link parts are rotatably connected by bearings in the same way. Rotation axes of the bearings 54a, 54b, and the like connecting the link parts extend from the rearward direction DB side to the forward direction DF side (in the present embodiment, the rotation axes are parallel to the forward direction DF side). Two connected link parts are relatively rotatable about the rotation axis within a predetermined angular range (for example, a range of less than 180 degrees).Accordingly, the rear link mechanism 50 can implement a structure for relatively tilting the rear wheel unit 16R and the vehicle body 12 with respect to the ground GL in the inward direction (the vehicle width direction). For example, when the tilting vehicle 10 rotates, as shown in FIG. Fig. As shown in Figure 3, the tilting vehicle 10 is tilted inward (the right direction DR) against a centrifugal force generated in the outward direction (the left direction DL). When the vehicle body is tilted inward to resist the centrifugal force, the rotation of the tilting vehicle 10 is stable. However, as the centrifugal force increases and the vehicle body 12 swings in the outward direction, the stability decreases. Therefore, in order to continue smooth cornering, it is necessary to adopt a posture in which the tilting vehicle 10 is intentionally tilted toward the inside of the curve. Therefore, the rear link part 50 can improve the posture stability of the tilting vehicle 10 during cornering by intentionally tilting the tilting vehicle 10 in the inside direction of the curve through the tilt motor 52.

[0028] The tilt motor 52 is an example of a device configured to drive the rear link 50 and is, for example, an electric motor. The tilt motor 52 is connected, for example, on the top side to the vertical link 50b and the lateral link 50d. The tilt motor 52 rotates the lateral link 50d with respect to the vertical link 50b. Accordingly, the wheels 14 (the vehicle body 12) are tilted in the inward direction (i.e., in the right direction or in the left direction in the vehicle width direction). Such tilting movement is also referred to as rolling movement. The tilt motor 52 and the vertical link 50b may be connected via gears. The tilt motor 52 and the lateral link 50d may be connected via gears. Hereinafter, a torque generated by the tilt motor 52 is also referred to as tilt motor torque.The tilt motor torque tilts the vehicle body 12. That is, it is possible to implement control of the relative tilt of the rear wheel unit 16R and the vehicle body 12 with respect to the ground GL in the inward direction. In another embodiment, the tilt motor may be attached to the rear wheel unit 16R, and an output side (rotation axis side) of the tilt motor may be connected to the vehicle body 12. In this case, the rear wheel unit 16R and the vehicle body 12 can be tilted in the inward direction by relatively tilting the rear wheel unit 16R and the vehicle body 12 with respect to the ground GL.

[0029] The Fig. The position SR1 shown in Figure 2 indicates a state in which the tilting vehicle 10 is upright, and the position shown in Fig. The position SR2 shown in Figure 3 indicates a state in which the tilting vehicle 10 is tilted with respect to the horizontal ground GL. As indicated by the attitude SR1, the wheels 14, which are the rear wheels, are upright with respect to the horizontal ground GL when the lateral connecting part 50d is perpendicular to the vertical connecting part 50b. The entire tilting vehicle 10 has an upright position with the vehicle body 12 with respect to the ground GL. An upward direction DVU of the vehicle body in Fig. 2 is an upward direction of the vehicle body 12. In a state where the tilting vehicle 10 is not tilted, the upward direction DVU of the vehicle body is equal to the upward direction DU. In the present embodiment, an upward direction determined in advance for the vehicle body 12 is used as the upward direction DVU of the vehicle body.

[0030] When the tilting vehicle 10 travels straight ahead in the SR1 position and the ground GL is uneven, the wheels 14 are displaced in the up / down direction by a parallel operation of the rear link 50, and the rear wheel unit 16R (the rear link 50) can move (swing) in the up / down direction with respect to the vehicle body 12 due to the cooperation between the rear link rod 46A and the rear spring member 48. When the tilting vehicle 10 travels on the uneven ground GL, the transmission of the up / down vibrations to the side of the vehicle body 12 is reduced, which contributes to improved driving stability.

[0031] In contrast, as can be seen from the SR2 posture in Fig. As can be seen from Fig. 3, when the vertical link part 50b rotates clockwise with respect to the lateral link part 50d in the rear view, a wheel 14R, which is a right rear wheel, moves relatively in one side of an upward direction DVU with respect to the vehicle body 12, and a wheel 14L, which is a left rear wheel, moves to an opposite side. Therefore, in a state where the wheels 14R and 14L, which are rear wheels, are in contact with the ground GL, the wheels 14L and 14R, and hence the vehicle body 12, are tilted in the right direction DR with respect to the ground GL. For example, the vehicle body 12 may be tilted in the inward direction (the right direction DR) to counteract the centrifugal force generated in the outward direction when the tilting vehicle 10 turns right.In this case, the degree of inclination of the vehicle body 12 in the inward direction can be adjusted accordingly by controlling the tilt motor 52. When the vertical link 50b rotates counterclockwise with respect to the lateral link 50d, the vehicle body 12 is tilted toward the left side DL. That is, the vehicle body 12 can be tilted in the same way at the time of a left turn to counteract the centrifugal force.

[0032] In the Fig. In the posture SR2 shown in Figure 3, the upward direction DVU of the vehicle body is inclined to the right direction DR with respect to the upward direction DU. Hereinafter, an angle between the upward direction DU and the upward direction DVU of the vehicle body when the tilting vehicle 10 is viewed in the forward direction DF is referred to as a roll angle Ar or pitch angle Ar. Here, "Ar > 0" means that the vehicle is tilted to the right in the direction DR, and "Ar < 0" means that the vehicle is tilted to the left in the direction DL. The roll angle Ar of the vehicle body 12 can be referred to as a roll angle Ar of the tilting vehicle 10 with the vehicle body 12.

[0033] Fig. 3, in which the posture SR2 is illustrated, shows a rear steering angle ACr of the rear connecting part 50. The rear steering angle ACr indicates an angle of an orientation of the vertical connecting part 50b with respect to an orientation of the lateral connecting part 50d. In the rear view illustrating the posture SR2, „ ACr = zero" means that the vertical connecting part 50b is perpendicular to the lateral connecting part 50d. "ACr > zero" means a state in which the vertical connecting part 50b is perpendicular to the lateral connecting part 50d from the state „ ACr = zero“ clockwise. Although not shown, „ ACr < 0" a state in which the vertical connecting part 50b with respect to the lateral connecting part 50d is from the state „ACr = 0" counterclockwise. As shown, the rear steering angle ACr is approximately equal to the roll angle Ar when the tilting vehicle 10 is on the horizontal ground GL (ie, the ground GL is perpendicular to the vertical upward direction DU).

[0034] As described later, the front wheel unit 16F includes a passive suspension 54 and a link member that can tilt the wheels 14, which are the front wheels, in the vehicle width direction while generating greater roll rigidity as the inclination (roll) of the vehicle body 12 increases. Therefore, the vehicle body 12 can be tilted in the vehicle width direction with respect to the ground even on the front wheel side. That is, the tilting vehicle 10 can adjust the posture of the vehicle body 12 in the vehicle width direction according to a driving condition or a road surface condition, and change the posture to a posture suitable for driving.

[0035] As described above, the rear link 50 on the rear wheel side can tilt (roll) the vehicle body 12 inward through the tilt motor 52, maintaining balance with the centrifugal force generated at the time of turning. In this case, the wheels 14 on the front wheel side can be rolled by rolling in the same way.

[0036] The rear link 50 and the front wheel side link, which will be described later, are examples of a tilting device (also referred to as a front tilting device or a rear tilting device) configured to tilt the vehicle body 12 in the vehicle width direction of the tilting vehicle 10. The tilting motor 52 (also referred to as a rear driving device) is an example of the driving device configured to generate a driving force (i.e., a tilting motor torque) for driving the rear tilting device. The driving force of the rear driving device is a force for rolling the vehicle body 12 inward with respect to the wheels 14, which are a pair of rear wheels.

[0037] The rear wheel unit 16R may have a locking mechanism (not shown) that stops the movement of the rear link 50. By operating the locking mechanism, the rear steering angle ACr can be fixed. This allows, for example, the rear steering angle ACr to be fixed to zero when the tilting vehicle 10 is parked to stabilize a parking position.

[0038] Next, the front wheel unit 16F is described. Fig. 4 is an exemplary and schematic perspective view illustrating a configuration of the passive suspension 54, which is the front wheel side link part (also referred to as a front link mechanism 38B) included in the front wheel unit 16F and provided on the front wheel side of the tilting vehicle 10. Fig. 4 shows the basic operation of the passive suspension 54, and illustrations of elements not included in the description are omitted.

[0039] The passive suspension 54 (the front linkage mechanism 38B), for example, is a known double wishbone type suspension and has upper arms 56, lower arms 58, ball joints 60 (only one side is shown), steering knuckles 62 (only one side is shown), and shock absorbers 64.

[0040] As described above, a basic structure of the double-wishbone type passive suspension 54 has a known structure, and a detailed description thereof will be omitted. A pair of upper arms 56 and lower arms 58, spaced apart from each other in a vehicle height direction, are provided on the left and right wheels 14, respectively. In the upper arm 56 and the lower arm 58, their end portions far from the wheel 14 are pivotally connected to a part of the vehicle body 12, and their end portions close to the wheel 14 are pivotally connected, via a ball joint 60, to a hub knuckle 62 connected to the wheel 14.One end of the hub knuckle 62 is pivotally connected to the upper arm 56, and the other end of the hub knuckle 62 is pivotally connected to the lower arm 58, thereby enabling pivoting in the vehicle width direction about approximately a central portion of the hub knuckle 62 and allowing the wheel 14 to be tilted in the vehicle width direction. The shock absorber 64 generates roll rigidity by relaxing and contracting, and generates a force against the centrifugal force at the time of turning, that is, a force that prevents the tilting vehicle 10 from being pivoted in the outward direction. In the case of . Fig. 4, one end side (lower end side) of the shock absorber 64 is pivotally connected to the lower arm 58. In another embodiment, one end side (lower end side) of the shock absorber 64 may be connected to the upper arm 56.

[0041] A rocker arm 66 extending in the vehicle width direction is connected to the other end side (upper end side) of the shock absorber 64 in the passive suspension 54 according to the present embodiment. The rocker arm 66 is, for example, an arcuate plate member and has two end portions pivotally connected to the upper end sides of the left and right shock absorbers 64, respectively. A central portion of the rocker arm 66 is pivotally connected to a part of the vehicle body 12. The rocker arm 66 has a function of enabling the tilting vehicle 10 to tilt by pivoting before the expansion and contraction of the shock absorber 64. That is, the start of the expansion and contraction operation of the shock absorber 64 can be delayed.This allows the tilting vehicle 10 to tilt the wheels 14 (the front wheels) in the inward direction (the vehicle width direction) of the tilting vehicle 10 by an extension and contraction amount of the shock absorbers 64 and a swing amount of the rocker arm 66. In other words, it is possible to relax a tilt amount of the wheel 14 (the front wheel) to be equal to or greater than a relaxation and contraction capability of the shock absorber 64, thereby contributing to expanding a range within which the vehicle attitude is stabilized at the time of turning.

[0042] The passive suspension 54 with the rocker arm 66 can prevent roll stiffness from being generated in a first range (first angle range) from the start of the tilt of the vehicle body 12 to a predetermined angle (up to a pivoting range of the rocker arm 66). The rocker arm 66 (the passive suspension 54) can generate roll stiffness by a spring force of the shock absorber 64 in a second range (a second angle range) in which the vehicle body 12 is tilted further than in the first range. That is, the passive suspension 54 according to the present embodiment has different roll stiffness characteristics according to a tilt degree of the tilting vehicle 10.That is, in a region where the inclination is slight (the first region), the roll rigidity is reduced to give priority to the slight inclination (slight lean), and in a region where the inclination is large (the second region), the roll rigidity is set high by giving priority to roll prevention. As a result, a tilting posture of the tilting vehicle 10 can be easily implemented when a turning radius is large or a vehicle speed at the time of turning is low and when the centrifugal force generated in the outward direction is small. When the centrifugal force is large, it is possible to reduce the instability of the tilting posture of the tilting vehicle 10 (the wheels 14 on the front wheel side) by increasing the roll rigidity (to improve a posture maintaining force).

[0043] Operations of the front wheel unit 16F configured in this way will be described with reference to the Fig. 5 and Fig. 6 described. Fig. 5 is an exemplary schematic diagram illustrating a state in which the tilting vehicle 10 is not tilted in the vehicle width direction (the inward direction) when the tilting vehicle 10 is viewed from the front. Fig. 6 is an exemplary schematic diagram illustrating a state in which the tilting vehicle 10 is tilted in the inward direction when the tilting vehicle 10 is viewed from the front. Fig. 5 and Fig. 6, the upper arms 56, the lower arms 58, the steering knuckles 62, the shock absorbers 64 and the rocker arm 66 of the front wheel unit 16F (the passive suspension 54) are schematically illustrated to facilitate understanding of the behavior of the tilting vehicle 10, and other configurations are not illustrated. Fig. 2 and Fig. 3 are views of the tilting vehicle 10 seen from the rear. Fig. 3 is a view showing that the tilting vehicle 10 turns to the right. In contrast, the Fig. 5 and Fig. 6 views of the tilting vehicle 10 seen from the front. Fig. 6 is a view showing that the tilting vehicle 10 turns to the left.

[0044] As described above, the upper arms 56 and the lower arms 58, which implement the passive suspension 54, are connected to the wheels 14 (front wheel) and the vehicle body 12. The left and right upper arms 56 and the left and right lower arms 58 pivot in opposite directions, thereby displacing the wheels 14 in the up / down direction according to the unevenness of the ground GL. That is, the transmission of an influence of the unevenness of the ground GL to the vehicle body 12 is reduced, which contributes to improving ride comfort. The upper arms 56 and the lower arms 58 pivot in the same direction, thereby tilting the wheels 14 and tilting the vehicle body 12 in the inward direction (the vehicle width direction) with respect to the ground GL in the same manner as the rear wheel unit 16R (the rear link part 50).

[0045] For example, if the tilting vehicle 10 is in a position SF1 in Fig. 5 stands upright without being inclined on the horizontal ground GL (that is, the ground GL is perpendicular to the vertically upward direction DU), the upper arm 56 and the lower arm 58 are parallel to the horizontal direction. In this case, the shock absorber 64 is in a stable state, and basically no spring force is generated. When the ground GL is uneven and the left and right wheels 14 are displaced up or down at the same time, the left and right upper arms 56 and the left and right lower arms 58 swing in opposite directions to absorb a displacement amount caused by the unevenness. When the ground GL is uneven and one of the wheels 14 is displaced up or down due to the unevenness, the upper arms 56 and the lower arms 58 swing in the same direction according to the unevenness and absorb the displacement amount caused by the unevenness.In this case, when the degree of unevenness is relatively small and the swing amount of the lower arm 58 is within the swing range of the rocker arm 66 to which the shock absorbers 64 are connected, the shock absorbers 64 do not expand and contract, and the displacement caused by the unevenness is absorbed only by the swing of the rocker arm 66 to stabilize the posture of the vehicle body 12. On the other hand, when the degree of unevenness exceeds the swing range of the rocker arm 66, the shock absorbers 64 start expanding and contracting, and the displacement amount caused by the unevenness is absorbed by the swing of the rocker arm 66 and the expansion and contraction of the shock absorbers 64.

[0046] Next, with reference to Fig. 6 describes the behavior of the front wheel unit 16F (the passive suspension 54) when the tilting vehicle 10 turns. As described above, when the tilting vehicle 10 turns, for example, in the left direction DL, a centrifugal force is generated in the outward direction (the right direction DR). Therefore, to cancel the centrifugal force, it is necessary to tilt the tilting vehicle 10 in the inward direction. In this case, the left and right upper arms 56 and the left and right lower arms 58 in the front wheel unit 16F pivot in the same direction, thereby tilting the wheels 14 and tilting the vehicle body 12 in the inward direction (the vehicle width direction) with respect to the ground GL.

[0047] For example, as in a Fig. 6, the tilting vehicle 10 may be tilted to the left when the tilting vehicle 10 turns left, which is the inward turn, to balance the centrifugal force generated in the outward direction. As described above, the tilting vehicle 10 may be intentionally tilted (leaned) in the inward direction by driving the tilt motor 52 on the rear wheel unit 16R side. In this case, the drive control of the tilt motor 52 is performed based on a target tilt angle (target turning information, target tilt angle) calculated based on the vehicle speed of the tilting vehicle 10 and the rotation angle (input angle) of the steering wheel 26, as well as a tilt angle (present tilt angle) actually obtained from the inertial measurement unit.In this case, the target tilt angle and the actual tilt angle may differ depending on the driving condition or the road surface condition. Therefore, the tilting vehicle 10 implements an ideal cornering attitude of the tilting vehicle 10 by controlling the tilt motor torque generated by the tilt motor 52 of the rear wheel unit 16R to eliminate a deviation between the target tilt angle and the actual tilt angle.

[0048] In the front wheel unit 16F (the passive suspension 54), the shock absorbers 64 expand at an initial stage of the tilting of the tilting vehicle 10, that is, when the centrifugal force is small, when the swing amount of the lower arm 58 (the upper arm 56) is within the swing range (the first range) of the rocker arm 66 to which the shock absorbers 64 are connected, the shock absorbers 64 do not relax and contract, and the tilting of the tilting vehicle 10 (the wheels 14) is enabled only by the swing of the rocker arm 66. That is, the tilt motor 52 can easily implement the ideal cornering attitude of the tilting vehicle 10 by generating the tilt motor torque to implement the target tilt angle.Conversely, when the centrifugal force increases and it is necessary to increase the inward tilt of the tilting vehicle 10 when the swing range of the rocker arm 66 is exceeded (in the case of the second range), the shock absorbers 64 begin to expand and contract to generate a repulsive force, thereby increasing the roll rigidity and resisting the increased centrifugal force. In this case, the shock absorber 64 on the inward-turning side is compressed, and the shock absorber 64 on the outward-turning side is expanded. However, in this case, the repulsive force caused by the shock absorbers 64 tends to balance with the centrifugal force generated in the outward direction and counteracts a control direction of the tilt motor 52 that tends to tilt the tilting vehicle 10 inward, and the tilting vehicle 10 is difficult to tilt inward.That is, it may be difficult to implement the ideal cornering attitude of the tilting vehicle 10 only by controlling the tilt motor 52 to implement the target tilt angle.

[0049] Here, the tilt motor 52 according to the present embodiment controls according to the roll stiffness generated by the shock absorbers 64 on the side of the wheel unit on which the tilt unit is not mounted, to generate the tilt motor torque and cancel the roll stiffness.

[0050] Fig. 7 is an exemplary and schematic block diagram illustrating a configuration of the control device 24 that performs tilt control in the tilting vehicle 10. The control device 24 includes a target tilt angle detection unit 24a, a present tilt angle detection unit 24b, a deviation detection unit 24c, a motor torque determination unit 24d, and a drive control unit 24e. The target tilt angle detection unit 24a may, for example, use a map created in advance through a test or the like to obtain the target tilt angle corresponding to the driving required by the driver based on the speed sensor 36 (the vehicle speed of the tilting vehicle 10) and the rotation angle (input angle) of the steering wheel 26.The present tilt angle detection unit 24b can detect the present tilt angle indicating a present tilt state of the tilting vehicle 10 through the inertial measurement unit included in the direction sensor 28 provided in the rear portion 12e of the vehicle body 12. The deviation detection unit 24c calculates the deviation between the acquired target tilt angle and the acquired present tilt angle. Then, the motor torque determination unit 24d determines the tilt motor torque to cancel the deviation between the target tilt angle and the present tilt angle determined by the inertial measurement unit.

[0051] Deviation detection unit 24c is obtained. The drive control unit 24e drives and controls the tilt motor 52 to output the tilt motor torque determined by the motor torque determination unit 24d.

[0052] For example, when the current tilt angle is smaller than the target tilt angle due to the repulsive force (roll stiffness) generated by the expansion and contraction of the shock absorbers 64, that is, when the tilt of the tilting vehicle 10 is insufficient, the tilt motor 52 is corrected and controlled to generate the tilt motor torque in a direction to increase the tilt. Conversely, when the current tilt angle is larger than the target tilt angle, when the road surface condition changes suddenly, that is, when the tilt of the tilting vehicle 10 is excessive, the tilt motor 52 is corrected and controlled to generate the tilt motor torque in a direction to decrease the tilt (the posture of the tilting vehicle 10 is raised).At this time, a correction value of the tilt motor 52 can be determined, for example, by using the map created in advance through a test or the like. This map can be related, for example, to the tilt motor torque of the tilt motor 52 to cancel the roll stiffness generated by the expansion and contraction of the shock absorbers 64.

[0053] Accordingly, according to the present embodiment of the tilting vehicle 10, the ideal cornering attitude of the tilting vehicle 10 can be realized by controlling the tilting motor 52 (the tilting unit) while taking into account the repulsive force (the roll rigidity) generated by the expansion and contraction of the shock absorbers 64. This makes it possible to provide the tilting vehicle 10 with a simple structure in which the roll stabilization by the roll rigidity of the suspension (the shock absorbers 64) of the front wheel unit 16F and the tilt control by the tilting unit of the rear wheel unit 16R are performed in a balanced manner, the stable handling is maintained, and the more stable tilt position during turning can be implemented, and cost savings can be easily realized.

[0054] In this way, by providing the tilting unit on the wheel unit at least at one of the front positions (the front wheels) and the rear position (the rear wheels) of the tilting vehicle 10 and providing the passive suspension 54 on the other wheel unit, the structure and control can be simplified compared to a configuration in which the tilting units are provided at both the front position and the rear position and both are controlled, which can contribute to reducing the cost of the tilting vehicle 10. Even if the tilting unit is mounted on one of the front and rear wheel units and the passive suspension 54 that generates roll rigidity is installed on the other of the wheel units, the stable tilting posture can be implemented at the time of turning while maintaining the stable driving performance of the tilting vehicle 10.

[0055] In dem in Fig.In the example shown in Fig. 4, an example is shown in which the stabilization range of the vehicle attitude at the time of turning is increased by using the rocker arm 66. In another embodiment, a structure that does not provide roll rigidity at a location (the first region) where the inclination (roll angle) of the vehicle body 12 is small may be used instead of the rocker arm 66 to achieve a similar effect. For example, by installing a passive stabilizer having an idle portion at a location (the first region) where the roll angle is small, no roll rigidity can be provided, the operation of extension and contraction of the shock absorbers 64 can be delayed (that is, the extension and contraction starts in the second region), the total amount of inclination can be increased, and the stabilization range of the vehicle attitude at the time of turning can be increased.In this case, too, the tilting posture of the tilting vehicle 10 can be easily implemented by not generating the roll stiffness in the first region when the centrifugal force generated in the outward direction is small. When the centrifugal force is large, by generating the roll stiffness caused by the shock absorbers 64 in the second region, the instability of the tilting posture of the tilting vehicle 10 (the wheels 14 on the front wheel side) can be reduced by the generated roll stiffness. Since the spring element included in the passive suspension 54 has ones in which the generated roll stiffness changes gradually according to the expansion and contraction state, for example, those that can generate small roll stiffness and large roll stiffness by using a variable shock absorber can be used.In this case, too, the generated roll stiffness can be reduced when the centrifugal force generated in the outward direction is small, and a suitable tilting attitude of the tilting vehicle 10 can be easily implemented. As the centrifugal force increases, it is possible to reduce the instability of the tilting attitude of the tilting vehicle 10 (the wheels 14 on the front wheel side) by increasing the roll stiffness generated in the second region.

[0056] As described above, the tilting vehicle 10 according to the present embodiment includes: a plurality of wheel units (rear wheel unit 16R, front wheel unit 16F) provided at least at a front position and a rear position of the vehicle body 12, each having a pair of wheels 14 spaced apart from each other in a width direction of the vehicle; a tilting unit provided near one of the wheel units and having a tilting mechanism (a mechanism configured to tilt the tilting vehicle 10 in an inward direction) configured to tilt the wheel unit and the vehicle body 12 relative to the ground in the inward direction, and a tilting drive unit (tilting motor 52) configured to drive the tilting mechanism; and the passive suspension 54 (the front link mechanism) provided at the other of the wheel units and configuredto generate roll stiffness when the vehicle body 12 is tilted with respect to the ground in the vehicle width direction. According to this configuration, for example, the tilt unit is provided in one of the wheel units at least at the front and rear positions of the vehicle body 12, and the passive suspension 54 is provided in the other of the wheel units. Therefore, it is possible to provide the tilting vehicle having a simple structure in which roll stabilization by the roll stiffness of the passive suspension 54 and tilt control by the tilt unit can be performed in a balanced manner, stable driving performance can be maintained, and a more stable tilt posture can be implemented at the time of turning, and having a configuration that easily realizes cost reduction.

[0057] In the embodiment described above, the passive suspension 54 may have different roll stiffness characteristics in a first range from the beginning of the inclination of the vehicle body 12 up to a predetermined angle and a second range in which the vehicle body 12 is inclined further than in the first range. For example, the passive suspension 54 may gradually increase the roll stiffness in the first range in which the inclination of the vehicle body 12 is small, and increase the roll stiffness by a rate of change of the roll stiffness that is greater than a rate of change of the first range in the second range in which the inclination exceeds that of the first range and becomes even greater. That is, the passive suspension 54 may be changed so that the roll stiffness increases as the inclination of the vehicle body 12 increases.In another embodiment, the passive suspension 54 may not generate the roll stiffness in the first region and generate the roll stiffness in the second region where the inclination increases. That is, the roll stiffness of the passive suspension 54 may be generated when the inclination of the vehicle body 12 (the wheels 14 on the front wheel side) exceeds a predetermined value. According to this configuration, in the first region where the inclination is small, the roll stiffness may be reduced to give priority to the inclination, and in the second region where the inclination is large, the roll stiffness may be increased by giving priority to roll prevention.Thereby, the roll stabilization by the roll rigidity of the passive suspension 54 and the tilt control by the tilt unit can be performed in a balanced manner, the stable driving performance can be maintained, and the more stable tilt posture can be implemented at the time of turning.

[0058] In the embodiment described above, the passive suspension 54 may include the upper arm 56 and the lower arm 58 that support the wheels 14, a pair of spring members (shock absorbers 64) provided separately from each other in the vehicle width direction and each having a lower end connected to one of the lower arms 58 and the upper arm 56, and the rocker arm 66 has end portions in the vehicle width direction that are respectively connected to upper ends of the pair of spring members, and a middle portion pivotally connected to the vehicle body 12.According to this configuration, for example, a structure can be easily implemented in which roll rigidity is not generated so as to give priority to tilt in the area (the first area) where the tilt is small, and roll rigidity is increased so as to give priority to roll stabilization in the area (the second area) where the tilt is large. A structure can be easily implemented in which the tilt amount of the tilting vehicle 10 is expanded to be equal to or greater than the expansion and contraction capability of the spring member (the shock absorber 64), and the stabilization range of the vehicle attitude at the time of turning is increased.

[0059] In the above-described embodiment, the weight of the vehicle body 12 can be distributed more toward the side of the wheel unit including the tilt unit than toward the side of the wheel unit equipped with the passive suspension. According to this configuration, for example, more torque generated by the tilt motor can be transmitted to the road surface (the ground GL), and the posture control performance by the tilt unit can be improved.

[0060] The principles, preferred embodiment, and mode of operation of the present invention have been described in the foregoing specification. However, the invention which is intended to be protected is not to be construed as limited to the disclosed embodiments. Moreover, the embodiments described herein are to be considered illustrative rather than restrictive. Others may make variations, changes, and substitute equivalents without departing from the spirit of the present invention. Accordingly, it is expressly intended that all variations, changes, and equivalents which fall within the spirit and scope of the present invention as defined by the claims be embraced therein. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2021 - 160 610

[0003]

Claims

[1] Tilting vehicle (10) with: a plurality of wheel units (16) provided at least at a front position and a rear position of a vehicle body (12) and each having a pair of wheels (14) spaced apart from each other in a vehicle width direction; a tilting unit provided near one of the wheel units and having a tilting mechanism configured to relatively tilt the wheel unit and the vehicle body in an inward direction with respect to a ground, and a tilting drive unit configured to drive the tilting mechanism; and a passive suspension (54) provided on the other of the wheel units and configured to generate roll stiffness when the vehicle body is inclined with respect to the ground in the width direction of the vehicle. [2] A tilting vehicle according to claim 1, wherein the passive suspension has different roll stiffness characteristics in a first region from a start of tilting of the vehicle body to a predetermined angle and in a second region in which the vehicle body is tilted further than in the first region. [3] Tilting vehicle according to claim 2, wherein the passive suspension has an upper arm (56) and a lower arm (58) which carry the wheels, a pair of spring elements (64) provided spaced apart from each other in the vehicle width direction and each having a lower end connected to one of the lower arm and the upper arm, and a rocker arm (66) having end portions in the vehicle width direction which are respectively connected to upper ends of the pair of spring members, and a central portion which is pivotally connected to the vehicle body. [4] A tilting vehicle according to claim 1, wherein a weight of the vehicle body is distributed more to a wheel unit side provided with the tilting unit than to a wheel unit side provided with the passive suspension.

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