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US-20260124869-A1 - TILITING SUSPENSION SYSTEM FOR A VEHICLE AND CONTROL METHOD FOR TILITING A VEHICLE

US20260124869A1US 20260124869 A1US20260124869 A1US 20260124869A1US-20260124869-A1

Abstract

The present disclosure is related to a tilting suspension system comprising a frame, a subframe, a longitudinal axis, an independent symmetrical front suspension, a steering mechanism, and a tilting mechanism, a tilt locking mechanism, a wheel alignment and caster adjustment unit, a controllable anti-roll bar unit, and a power tilting unit. The present disclosure is also related to a control method for tilting such a vehicle comprising selecting a driving mode of the vehicle and activating the driving mode.

Inventors

  • Arturas Mikalauskas
  • Jurgis Lecas
  • Lukas Baciauskas

Assignees

  • UAB RIMTI RATAI

Dates

Publication Date
20260507
Application Date
20250923

Claims (20)

  1. 1 . A tilting suspension system comprising a frame ( 1 ), a subframe ( 2 ), a longitudinal axis ( 3 ), an independent symmetrical front suspension ( 4 ), a steering mechanism ( 5 ), and a tilting mechanism ( 6 ), wherein the tilting suspension system further comprises a tilt locking mechanism ( 7 ).
  2. 2 . A tilting suspension system according to claim 1 , further comprising a wheel alignment and caster adjustment unit ( 8 ).
  3. 3 . A tilting suspension system according to claim 1 , further comprising a controllable anti-roll bar unit ( 9 ).
  4. 4 . A tilting suspension system according to claim 1 , further comprising a power tilting unit ( 10 ), a tilt controller ( 10 . 5 ), a motor controller ( 10 . 6 ), wherein the power tilting unit ( 10 ) comprises a motor ( 10 . 1 ), gear reducer ( 10 . 2 ), safety coupler ( 10 . 3 ), and torque sensor ( 10 . 4 ).
  5. 5 . The tilting suspension system according to claim 1 , wherein the tilt locking mechanism ( 7 ) comprises a friction segment ( 7 . 1 ), which is connected to the subframe ( 2 ), and a friction caliper ( 7 . 2 ) that houses friction pads ( 7 . 3 ) and a hydraulic cylinder ( 7 . 4 ), wherein the hydraulic cylinder ( 7 . 4 ) connects to a hydraulic control cylinder ( 7 . 6 ) through a hydraulic line ( 7 . 5 ), wherein the hydraulic control cylinder ( 7 . 6 ) is operated by a tilt lock handle ( 7 . 7 ).
  6. 6 . The tilting suspension system according to claim 1 , wherein the independent symmetrical front suspension ( 4 ) comprises symmetrical left and right sides comprising an upper control arm ( 4 . 1 ) and a lower control arm ( 4 . 2 ), both of which are V-shaped, a wheel knuckle ( 4 . 3 ) and a wheel axle ( 4 . 4 ), wherein the upper control arm ( 4 . 1 ) is movably connected to the slider ( 8 . 1 ), while the lower control arm ( 4 . 2 ) connects to the frame ( 1 ) and the pointed ends of both control arms are movably attached to the wheel knuckle ( 4 . 3 ) and the wheel axle ( 4 . 4 ), the steering mechanism ( 5 ) comprises a steering wheel ( 5 . 1 ), a steering column ( 5 . 2 ), a steering column bushing ( 5 . 3 ), a universal joint ( 5 . 4 ), a steering link axle ( 5 . 5 ), a steering link ( 5 . 6 ), a slip joint ( 5 . 7 ), and a tie rods ( 5 . 8 ), the tilting mechanism ( 6 ) comprises a main lever ( 6 . 1 ) connected at one end to the steering column bushing ( 5 . 3 ) and at the other end connected to a pinion ( 6 . 5 ), wherein the main lever ( 6 . 1 ) is movably attached to the frame ( 1 ) via two bearing-axis joints ( 6 . 2 , 6 . 3 ) and the pinion ( 6 . 5 ) is mounted on the frame ( 1 ) while a gear ( 6 . 6 ) is mounted on the subframe ( 2 ), forming a gear pair ( 6 . 4 ).
  7. 7 . The tilting suspension system according to claim 4 , wherein the tilt controller ( 10 . 5 ) further comprises inputs connected to a tilt angle sensor ( 10 . 7 ), a wheel steering angle sensor ( 10 . 8 ), a speed sensor ( 10 . 9 ), a pressure sensor ( 10 . 10 ), an inertial measurement unit ( 10 . 11 ), a drive mode selector ( 10 . 12 ), and a torque sensor ( 10 . 4 ), and the outputs of the tilt controller ( 10 . 5 ) are connected to a motor controller ( 10 . 6 ).
  8. 8 . The tilting suspension system according to claim 2 , wherein the wheel alignment and caster adjustment unit ( 8 ) comprises a slider ( 8 . 1 ) connected to the frame ( 1 ) via linear bearings ( 8 . 2 , 8 . 3 ).
  9. 9 . The tilting suspension system according to claim 3 , wherein the controllable anti-roll bar unit ( 9 ) comprises torsion bars ( 9 . 1 , 9 . 2 ) connected to the lower control arms ( 4 . 2 ) via links ( 9 . 3 , 9 . 4 ), and further comprises a hydraulic clutch ( 9 . 5 ).
  10. 10 . A tilting suspension system according to claim 2 , further comprising a controllable anti-roll bar unit ( 9 ).
  11. 11 . A tilting suspension system according to claim 2 , further comprising a power tilting unit ( 10 ), a tilt controller ( 10 . 5 ), a motor controller ( 10 . 6 ), wherein the power tilting unit ( 10 ) comprises a motor ( 10 . 1 ), gear reducer ( 10 . 2 ), safety coupler ( 10 . 3 ), and torque sensor ( 10 . 4 ).
  12. 12 . The tilting suspension system according to claim 2 , wherein the independent symmetrical front suspension ( 4 ) comprises symmetrical left and right sides comprising an upper control arm ( 4 . 1 ) and a lower control arm ( 4 . 2 ), both of which are V-shaped, a wheel knuckle ( 4 . 3 ) and a wheel axle ( 4 . 4 ), wherein the upper control arm ( 4 . 1 ) is movably connected to the slider ( 8 . 1 ), while the lower control arm ( 4 . 2 ) connects to the frame ( 1 ), and the pointed ends of both control arms are movably attached to the wheel knuckle ( 4 . 3 ) and the wheel axle the steering mechanism ( 5 ) comprises a steering wheel ( 5 . 1 ), a steering column ( 5 . 2 ), a steering column bushing ( 5 . 3 ), a universal joint ( 5 . 4 ), a steering link axle ( 5 . 5 ), a steering link ( 5 . 6 ), a slip joint ( 5 . 7 ), and a tie rods ( 5 . 8 ), the tilting mechanism ( 6 ) comprises a main lever ( 6 . 1 ) connected at one end to the steering column bushing ( 5 . 3 ) and at the other end connected to a pinion ( 6 . 5 ), wherein the main lever ( 6 . 1 ) is movably attached to the frame ( 1 ) via two bearing-axis joints ( 6 . 2 , 6 . 3 ) and the pinion ( 6 . 5 ) is mounted on the frame ( 1 ) while a gear ( 6 . 6 ) is mounted on the subframe ( 2 ), forming a gear pair ( 6 . 4 ).
  13. 13 . The tilting suspension system according to claim 6 , wherein the tilt controller ( 10 . 5 ) further comprises inputs connected to a tilt angle sensor ( 10 . 7 ), a wheel steering angle sensor ( 10 . 8 ), a speed sensor ( 10 . 9 ), a pressure sensor ( 10 . 10 ), an inertial measurement unit ( 10 . 11 ), a drive mode selector ( 10 . 12 ), and a torque sensor ( 10 . 4 ), and the outputs of the tilt controller ( 10 . 5 ) are connected to a motor controller ( 10 . 6 ).
  14. 14 . The tilting suspension system according to claim 6 , wherein the wheel alignment and caster adjustment unit ( 8 ) comprises a slider ( 8 . 1 ) connected to the frame ( 1 ) via linear bearings ( 8 . 2 , 8 . 3 ).
  15. 15 . The tilting suspension system according to claim 6 , wherein the controllable anti-roll bar unit ( 9 ) comprises torsion bars ( 9 . 1 , 9 . 2 ) connected to the lower control arms ( 4 . 2 ) via links ( 9 . 3 , 9 . 4 ), and further comprises a hydraulic clutch ( 9 . 5 ).
  16. 16 . A control method for tilting a vehicle comprising a tilting suspension system comprising a frame ( 1 ), a subframe ( 2 ), a longitudinal axis ( 3 ), an independent symmetrical front suspension ( 4 ), a steering mechanism ( 5 ), and a tilting mechanism ( 6 ) and a tilt locking mechanism ( 7 ), a wheel alignment and caster adjustment unit ( 8 ), a controllable anti-roll bar unit ( 9 ), and a power tilting unit ( 10 ), a tilt controller ( 10 . 5 ), a motor controller ( 10 . 6 ), wherein the method comprises selecting a driving mode of the vehicle and activating the tilt controller ( 10 . 5 ), wherein the tilt controller ( 10 . 5 ) is disabled and the safety coupler ( 10 . 3 ) is disconnected, or the tilt controller ( 10 . 5 ) is enabled and the safety coupler ( 10 . 3 ) is connected, the torque of the main lever ( 6 . 1 ) is assisted by the power tilting unit ( 10 ), or the tilt controller ( 10 . 5 ) is enabled and the safety coupler ( 10 . 3 ) is connected, the torque of the main lever ( 6 . 1 ) is autonomously controlled by the power tilting unit ( 10 ) and the power tilting unit ( 10 ) autonomously decides and tilts the body depending on reading from a tilt angle sensor ( 10 . 7 ), a wheel steering angle sensor ( 10 . 8 ), a speed sensor ( 10 . 9 ), a pressure sensor ( 10 . 10 ), and inertial measurement unit ( 10 . 11 ), a torque sensor ( 10 . 4 ) sends a signal proportional to the tilt force when the main lever ( 6 . 1 ) is tilted to the left or right from its central position, wherein the signal is amplified by the tilt controller ( 10 . 5 ), which then activates the motor ( 10 . 1 ) through the motor controller ( 10 . 6 ), wherein the motor ( 10 . 1 ) turns the gear pair ( 6 . 4 ) via the gear reducer ( 10 . 2 ) and the safety coupler ( 10 . 3 ), facilitating easier tilting of the main lever ( 6 . 1 ), calculating the assistive tilting force required by the vehicle driver using the tilt controller ( 10 . 5 ) from signals of a tilt angle sensor ( 10 . 7 ), a wheel steering angle sensor ( 10 . 8 ), a speed sensor ( 10 . 9 ), a pressure sensor ( 10 . 10 ), and inertial measurement unit ( 10 . 11 ), which force is subsequently applied to the motor ( 10 . 1 ) via the motor controller ( 10 . 6 ), securing the frame ( 1 ) and the subframe ( 2 ) of the vehicle at any tilt angle using the tilt locking mechanism ( 7 ), wherein the tilt angle is chosen by the driver of the vehicle, wherein locking force is varied based on pressure applied to a tilt lock handle ( 7 . 7 ), adjusting friction between the frame ( 1 ) and the subframe ( 2 ) to unlocked, partially locked, or fully locked, switching the drive mode of the vehicle to fully manual by disconnecting the safety coupler ( 10 . 3 ) from the motor ( 10 . 1 ) and the gear reducer ( 10 . 2 ), if an error in the tilting suspension system is detected by the tilt controller ( 10 . 5 ).
  17. 17 . A control method for tilting a vehicle according to claim 16 , wherein the wheel alignment and caster adjustment unit ( 8 ) operate by moving the slider ( 8 . 1 ) either forward or backward, wherein changing the position of the slider ( 8 . 1 ) alters the caster angle and wheel alignment, wherein wheel knuckles ( 4 . 3 ) and wheels shift slightly inward when the slider moves toward the rear of the vehicle and outward when it moves toward the front, configuring independent symmetrical front suspension ( 4 ) to increase vehicle stability.
  18. 18 . A control method for tilting a vehicle according to claim 17 , the controllable anti-roll bar unit ( 9 ) is enabled when the hydraulic clutch ( 9 . 5 ) connects the torsion bars ( 9 . 1 , 9 . 2 ), the anti-roll bar unit ( 9 ) is controlled by the tilt locking mechanism ( 7 ) and by the power tilting unit ( 10 ), and when the frame ( 1 ) is not locked with the subframe ( 2 ) the torsion bars ( 9 . 1 , 9 . 2 ) are not connected and do not affect the operation of the independent symmetrical front suspension ( 4 ), wherein the controllable anti-roll bar unit ( 9 ) balances the load between both sides of the independent symmetrical front suspension ( 4 ), wherein during turns, the wheel knuckles ( 4 . 3 ) move so that one side rises while the other side lowers, wherein the anti-roll bar unit ( 9 ) counteracts this tilt when the tilt locking mechanism ( 7 ) is engaged to improve tire grip, wherein the hydraulic clutch ( 9 . 5 ) either connect or disconnect the torsion bars ( 9 . 1 , 9 . 2 ), the control of the clutch ( 9 . 5 ) is engaged together with the tilt locking mechanism ( 7 ).
  19. 19 . A control method for tilting a vehicle according to claim 16 , the controllable anti-roll bar unit ( 9 ) is enabled when the hydraulic clutch ( 9 . 5 ) connects the torsion bars ( 9 . 1 , 9 . 2 ), the anti-roll bar unit ( 9 ) is controlled by the tilt locking mechanism ( 7 ) and by the power tilting unit ( 10 ), and when the frame ( 1 ) is not locked with the subframe ( 2 ) the torsion bars ( 9 . 1 , 9 . 2 ) are not connected and do not affect the operation of the independent symmetrical front suspension ( 4 ), wherein the controllable anti-roll bar unit ( 9 ) balances the load between both sides of the independent symmetrical front suspension ( 4 ), wherein during turns, the wheel knuckles ( 4 . 3 ) move so that one side rises while the other side lowers, wherein the anti-roll bar unit ( 9 ) counteracts this tilt when the tilt locking mechanism ( 7 ) is engaged to improve tire grip, wherein the hydraulic clutch ( 9 . 5 ) either connect or disconnect the torsion bars ( 9 . 1 , 9 . 2 ), the control of the clutch ( 9 . 5 ) is engaged together with the tilt locking mechanism ( 7 ).
  20. 20 . A control method for tilting a vehicle according to claim 16 , wherein the tilting of the vehicle frame ( 1 ) along with the seats and the vehicle body and the steering of the front wheels are performed as separate independent actions, and wherein when the vehicle is stationary, the frame ( 1 ) and the entire vehicle body is tilted without affecting the front wheels, and the front wheels are steered without tilting the frame ( 1 ) and the entire vehicle body.

Description

PRIORITY This application claims priority of the U.S. Provisional Application number 63/714,189 which was filed on Oct. 31, 2024 and the content of which is incorporated herein by reference. FIELD OF THE INVENTION The invention relates to the field of automotive, in particular, the present invention relates to a tilting suspension system and a control method for tilting vehicles. BACKGROUND ART As cities grapple with the challenges of CO2 and noise pollution from combustion engine-driven cars, as well as the scarcity of parking space for conventional automobiles, the need for innovative solutions becomes increasingly evident. Tilting vehicles offer a promising solution by addressing these pain points. Their narrow, compact size, maneuverability, and potential for electric powertrain propulsion make them an ideal fit for urban environments, efficiently transporting individuals or smaller cargo while minimizing environmental impact. Given the growing market interest in tilting vehicles, advancements have been made to enhance their safety, ease of operation, compactness, and performance, aligning them more closely with conventional automobiles. In U.S. Pat. No. 7,850,180 a vehicle is disclosed where steering is achieved by turning a steering wheel, which directs front suspension, and the vehicle's tilting is controlled by driver's legs. This is done by moving upper or lower suspension rods directly or through additional rods. However, in tilting vehicles, drivers typically use their legs to maintain body balance, making it uncomfortable to also control the vehicle's tilt with their legs. Another known solution is disclosed in US patent application, publication No.: US2014091551.The disclosed technology comprises mounting front suspension and steering wheel on front part of a vehicle frame, which is connected to rear part of the frame by an axle that is slightly bent upwards (see patent no.). When the steering wheel is turned to either side, the vehicle body tilts in the same direction, with the tilt angle determined by the angle of the axle. However, a drawback of this design is that the tilt of the vehicle is structurally linked to the steering, limiting independent control over both the tilt and the steering. Patent no. EP3428048 describes a three-wheeled vehicle with a steering mechanism that features two distinct units: one for steering and one for tilting. Both the steering and tilting are executed relative to the front frame, where the front suspension and steering mechanisms are mounted. While the steering and tilting mechanisms are independent of each other, they are both controlled by the steering wheel, which rotates around its axis. Similar to the solutions described above, steering and tilting are linked and can only be performed simultaneously, not independently. U.S. Pat. No. 10,737,720 discloses a vehicle body tilting system that uses a servo motor in conjunction with a mechanical gear reducer. However, this system lacks a torque sensor and a control channel that would directly manage the body's tilt during turns. The vehicle's tilt is not determined by the driver but is instead controlled by the electro-mechanical tilting system. This limitation restricts the functionality and versatility of the tilting vehicle. Lithuania patent No.: 6792 discloses a three-wheel drive control devices and method of leaning a three wheeled vehicle. Direction of movement of the vehicle is controlled by rotating the steering wheel about its axis and the leaning of the vehicle is controlled by the steering wheel, when the steering shaft is turned to the right and left from the neutral (central) position. Lithuania patent No.: 6990 discloses a control mechanisms for tilting three-wheeled vehicles. The control mechanism of a three-wheeled tilting vehicle consists of the steering and the tilting units, which are interconnected with the steering wheel, the steering column, and the steering wheel bushing. Patent application No.: PCT/IB2020/054225, publication No.: WO2020225716 discloses a leaning tricycle and its steering and a leaning method. Direction of the vehicle is initiated by the steering wheel and the tilt of the vehicle is controlled by tilting the same steering wheel shaft to the left or the right from neutral (center) position. The tilting three-wheeled vehicle consists of the frame, which has a motor, seats, single drive wheel, and the vehicle body in the back, and the two-wheeled independent symmetric suspension with a control unit in the front part of the frame. The solution is unique for its underframe mounted on the frame axles as well as the control unit which consists of two separate units—the steering unit and the tilting unit, both of which are connected by the steering wheel and the steering shaft which is mounted in the steering shaft longitudinal bushing. The steering unit features mechanical components for vehicle steering which are connected between the steering shaft and the wheel knuckles. The