Front wheel steering structure with adjustable dragging torque

Abstract

The invention relates to the field of front wheel steering structures of two-wheeled vehicles, and discloses a front wheel steering structure with an adjustable drag torque. Through a front fork arm, a tire is arranged in the middle of the front fork arm, a hub is arranged in the middle of the tire, a middle shaft is arranged in the middle of the hub, an adjusting assembly is arranged outside the middle shaft, and a reset assembly is arranged outside the front fork arm; the adjusting assembly comprises an eccentric sleeve, the eccentric sleeve is arranged outside the middle shaft in a sleeving mode, a planetary gear is arranged outside the middle shaft, a worm gear is fixedly connected to the outer portion of the planetary gear, and a driving motor is fixedly connected to the outer portion of the front fork arm. Through cooperation of the eccentric sleeve and the worm and gear transmission mechanism, dynamic stepless adjustment of the front wheel drag torque is achieved. A dynamic drag torque control monitoring system is used for carrying out self-adaptive adjustment on geometric parameters of working conditions, and the technical contradiction that a traditional fixed geometric steering structure cannot give consideration to low-speed steering flexibility and high-speed driving stability at the same time is solved.

Description

Technical Field

[0001] This invention relates to the field of front wheel steering structures for two-wheeled vehicles, specifically an adjustable drag torque front wheel steering structure. Background Technology

[0002] The front-wheel steering performance of two-wheeled vehicles and self-balancing vehicles largely depends on the setting of key geometric parameters such as drag torque. Existing front-wheel steering structures generally employ a fixed kingpin caster angle and wheel center offset design. This fixed parameter configuration has inherent limitations when dealing with complex and changing driving conditions. To ensure the vehicle's straight-line stability and anti-interference ability during high-speed cruising, a large drag torque is usually required to provide sufficient self-centering torque. However, this results in excessive steering resistance at low speeds, when turning on the spot, or parking, leading to heavy handling and a lack of agility. Conversely, prioritizing the reduction of drag torque to optimize low-speed handling weakens the stability margin at high speeds, making the vehicle more susceptible to front-wheel shimmy caused by road unevenness.

[0003] While some existing technologies attempt to modify steering geometry using variable structural designs, these methods primarily rely on linear sliding guides or complex linkage mechanisms to adjust wheel center positions. Such linear reciprocating motion structures suffer from insufficient mechanical stiffness, especially under emergency braking conditions where the steering components must withstand enormous longitudinal shear forces, making the sliding surfaces highly susceptible to deformation or jamming. Furthermore, linear sliding mechanisms struggle to achieve high-level dust and water resistance, leading to increased clearances over time. This increased mechanical play severely reduces steering control accuracy and can even induce structural vibrations.

[0004] Furthermore, existing electronically controlled variable steering systems rely excessively on the active holding capability of the actuators and generally lack robust passive failure safety mechanisms. When the control system experiences a power outage, sensor malfunction, or actuator jamming, if the steering structure happens to be in a low-stability geometric state with low drag torque, the system cannot automatically return to a high-stability setting. At this point, the vehicle will lose sufficient mechanical self-centering ability, making it difficult for the driver to maintain balance through the vehicle's own dynamic characteristics, which can easily lead to loss of control and a fall. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an adjustable drag torque front wheel steering structure, which solves the problems of traditional fixed geometry steering structures being unable to balance low-speed handling agility and high-speed driving stability, as well as the safety risks caused by the lack of power failure protection.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: an adjustable drag torque front wheel steering structure, including a front fork arm, a tire is disposed in the middle of the front fork arm, a wheel hub is disposed in the middle of the tire, a bottom axle is disposed in the middle of the wheel hub, an adjustment component is disposed outside the bottom axle, and a reset component is disposed outside the front fork arm. The adjustment assembly includes an eccentric sleeve fitted outside the central shaft. A planetary gear is disposed outside the central shaft, and a worm gear is fixedly connected to the outside of the planetary gear. A drive motor is fixedly connected to the outside of the front fork arm, and a worm is fixedly connected to the output end of the drive motor. The worm meshes with the worm gear. A dynamic drag torque control and monitoring system is installed in the middle of the front fork arm, and the dynamic drag torque control and monitoring system is electrically connected to the drive motor.

[0007] Furthermore, the dynamic drag torque control and monitoring system includes a data acquisition module, a state analysis module, a target calculation module, and an execution drive module. The data acquisition module is used to acquire the vehicle's speed signal, roll angle signal, and steering angle signal in real time. The state analysis module is connected to the data acquisition module and is configured to determine the vehicle's current driving condition based on the acquired signals. The target calculation module is connected to the state analysis module and internally stores a mapping table between drag torque and driving conditions, configured to calculate the target wheel center offset required under the current conditions. The execution drive module is connected to the target calculation module and the drive motor, configured to convert the target wheel center offset into a motor pulse signal and control the drive motor to rotate to a specified position.

[0008] Furthermore, the data acquisition module includes a wheel speed sensor and an inertial measurement unit. The wheel speed sensor is located at the tire or the bottom bracket, and the inertial measurement unit is located on the front fork or the frame. The dynamic drag torque control and monitoring system also includes a position feedback module, the output of which is connected to the input of the drive module. The position feedback module includes an angle encoder, which is coaxially connected to the shaft of the drive motor or the eccentric sleeve to form a closed-loop position control.

[0009] Furthermore, the target calculation module is configured to execute the following control logic: when the state analysis module outputs a low-speed range signal, the target calculation module outputs a first control signal to drive the eccentric sleeve to rotate to a first angular position, causing the central shaft to shift backward relative to the steering axis of the fork arm, thereby reducing the drag torque; when the state analysis module outputs a high-speed range signal, the target calculation module outputs a second control signal to drive the eccentric sleeve to rotate to a second angular position, causing the central shaft to shift forward relative to the steering axis of the fork arm, thereby increasing the drag torque. The reset component is an elastic energy storage element connected between the eccentric sleeve and the fork arm, and its preload direction is configured to push the eccentric sleeve to the second angular position.

[0010] Furthermore, the reset assembly includes a normally closed electromagnetic clutch, which is disposed at the output end of the drive motor, and a gas spring is disposed outside the central shaft. The normally closed electromagnetic clutch is configured to automatically switch to a disengaged state when the dynamic drag torque control monitoring system is powered off or malfunctions, thereby releasing the rigid connection between the drive motor and the adjustment assembly and allowing the gas spring to release energy to drive the mechanism to reset.

[0011] Preferably, a bushing is provided on the outside of the central shaft, and an oil seal is provided on the outside of the bushing.

[0012] Preferably, a disc brake disc is provided on the outside of the wheel hub, and the disc brake disc is coaxially arranged with the central axle.

[0013] Preferably, a speed sensing coil is provided on the side of the wheel hub, and the speed sensing coil is coaxially arranged with the central axis.

[0014] Preferably, the tire is provided with a mudguard on its exterior, and the mudguard is fixedly connected to the exterior of the front fork arm.

[0015] Preferably, a front shock absorber is provided on the outside of the front fork arm, and the bottom end of the front shock absorber is located between the gas spring and the front fork arm.

[0016] This invention provides an adjustable drag moment front wheel steering structure. It has the following beneficial effects: 1. This invention achieves dynamic stepless adjustment of the front wheel drag torque through the cooperation of an eccentric sleeve and a worm gear transmission mechanism. The dynamic drag torque control and monitoring system, based on vehicle speed and roll angle data, drives the eccentric sleeve to rotate at low speeds to adjust the wheel center offset, reducing drag torque and thus lowering steering resistance; at high speeds, it adjusts in the opposite direction to increase drag torque and enhance the return torque. This condition-based adaptive adjustment of geometric parameters resolves the technical contradiction of traditional fixed-geometry steering structures in balancing low-speed steering agility and high-speed driving stability.

[0017] 2. This invention integrates a failure protection reset mechanism comprising a normally closed electromagnetic clutch and an elastic energy storage component, ensuring the active safety performance of the vehicle. When the dynamic drag torque control monitoring system loses power or malfunctions, the electromagnetic clutch automatically disengages, cutting off the rigid connection between the drive motor and the eccentric sleeve and releasing the self-locking state of the worm gear. Subsequently, the elastic energy storage component releases preload, forcibly driving the eccentric sleeve to rotate and lock to the maximum drag torque position. This mechanism ensures that after the dynamic drag torque control monitoring system fails, the vehicle can automatically return to a highly stable geometric state using mechanical inertia, preventing loss of control accidents caused by the steering geometry remaining in a low-stability range.

[0018] 3. This invention uses a rotary eccentric sleeve structure to replace the traditional linear sliding mechanism to adjust the wheel center position, which improves the mechanical rigidity and sealing durability of the steering assembly when subjected to braking shear force and road impact. Combined with the real-time feedback of the angle encoder, this structure ensures the execution accuracy of drag torque adjustment under high load conditions and effectively suppresses the front wheel shimmy phenomenon caused by the mechanism play. Attached Figure Description

[0019] Figure 1 This is a perspective view of the tire of the present invention; Figure 2 This is a schematic diagram of the front fork arm structure of the present invention; Figure 3 This is a schematic diagram of the worm gear structure of the present invention; Figure 4 This is a schematic diagram of the planetary gear structure of the present invention; Figure 5 This is a schematic diagram of the disc brake structure of the present invention.

[0020] The components include: 1. Tire; 2. Front fork arm; 3. Mudguard; 4. Gas spring; 5. Front shock absorber; 6. Disc brake disc; 7. Bottom bracket; 8. Drive motor; 9. Eccentric sleeve; 10. Planetary gear; 11. Worm gear; 12. Worm; 13. Normally closed electromagnetic clutch; 14. Oil seal; 15. Wheel hub; 16. Speed ​​sensor coil; 17. Bushing. Detailed Implementation

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Please see the appendix Figure 1 and attached Figure 2This invention provides an adjustable drag torque front wheel steering structure, including a front fork 2, a tire 1 disposed in the middle of the front fork 2, a wheel hub 15 disposed in the middle of the tire 1, a central axle 7 disposed in the middle of the wheel hub 15, an adjustment component disposed outside the central axle 7, and a reset component disposed outside the front fork 2. The adjustment assembly includes an eccentric sleeve 9, which is sleeved on the outside of the central shaft 7. A planetary gear 10 is provided on the outside of the central shaft 7. A worm gear 11 is fixedly connected to the outside of the planetary gear 10. A drive motor 8 is fixedly connected to the outside of the front fork arm 2. A worm 12 is fixedly connected to the output end of the drive motor 8. The worm 12 meshes with the worm gear 11. A dynamic drag torque control and monitoring system is installed in the middle of the front fork arm 2. The dynamic drag torque control and monitoring system is electrically connected to the drive motor 8.

[0023] The front fork arm 2 serves as a basic support component. The front fork arm 2 is made of high-strength aluminum alloy or carbon fiber composite material, with its bottom end extending to accommodate the front wheel assembly. A tire 1 is located in the middle region of the front fork arm 2, and the tire 1 is supported by a wheel hub 15. The wheel hub 15 is located at the geometric center of the tire 1, and a bottom axle 7 is mounted in its center. The bottom axle 7 defines the axis of rotation of the wheel and bears the vertical load of the vehicle. The bottom axle 7 is movably connected to the front fork arm 2 via an adjusting assembly; the connection interface is located between the outside of the bottom axle 7 and the axle hole of the front fork arm 2.

[0024] The core of the adjustment assembly is the eccentric sleeve 9. The eccentric sleeve 9 is a cylindrical component with a preset eccentricity between the axis of its inner cylindrical surface and the axis of its outer cylindrical surface. The outer cylindrical surface of the eccentric sleeve 9 is rotatably mounted within the shaft hole of the fork arm 2, and the central shaft 7 is inserted and fixed within the inner cylindrical hole of the eccentric sleeve 9. In this structure, the rotational movement of the eccentric sleeve 9 relative to the fork arm 2 forces the center of the inner hole of the eccentric sleeve 9 to rotate around the rotation center of the outer cylindrical surface, driving the central shaft 7 to produce horizontal and vertical displacements.

[0025] To drive the rotation of the eccentric sleeve 9, a drive motor 8 is externally fixed to the front fork arm 2. A worm gear 12, made of high-hardness alloy steel, is coaxially connected to the output end of the drive motor 8. A planetary gear 10 and a worm wheel 11 are coaxially mounted externally to the eccentric sleeve 9 or the central shaft 7, and the worm wheel 11 meshes with the worm gear 12. The worm wheel 11 and worm gear 12 mechanism converts the high-speed, low-torque output of the drive motor 8 into low-speed, high-torque motion, driving the eccentric sleeve 9 to rotate. This mechanism has a reverse self-locking characteristic, meaning that only the active rotation of the worm gear 12 can drive the worm wheel 11; when the worm wheel 11 is subjected to external impact torque, it cannot drive the worm gear 12 in the reverse direction, thus maintaining the adjusted position.

[0026] The front fork arm 2 is externally equipped with a reset component, specifically an elastic energy storage element. One end of the elastic energy storage element is connected to the front fork arm 2, and the other end is connected to the eccentric sleeve 9 or its synchronous rotation component. The elastic energy storage element is preloaded with a preload force, which is configured to continuously apply a rotational torque to the eccentric sleeve 9 towards a specific angular position, corresponding to the high-speed stable operating condition of the vehicle.

[0027] A dynamic drag torque control and monitoring system is installed in the middle or upper part of the front fork arm 2. This system is encapsulated in a protective housing and connected to the drive motor 8 via a wiring harness, and also connected to sensor units distributed throughout the vehicle. The system's hardware architecture consists of a central processing unit, sensor components, and actuation drive circuitry. The data acquisition module includes wheel speed sensors and an inertial measurement unit. The wheel speed sensors are located at the point of relative rotation between the wheel hub 15 and the central axle 7, using Hall effect or photoelectric principles to monitor wheel speed. The inertial measurement unit is rigidly mounted on the upper part of the front fork arm 2 or the frame, integrating a MEMS gyroscope and accelerometer to collect vehicle roll angle and steering angle data.

[0028] The position feedback module, including an angle encoder, is used to construct a closed-loop position control. The angle encoder is coaxially connected to the drive motor 8 shaft or the eccentric sleeve 9, detecting the rotation angle in real time and feeding it back to the execution drive module. The state analysis module, target calculation module, and execution drive module reside in the central processing unit. The state analysis module receives signals from the data acquisition module; the target calculation module calculates the target wheel center offset based on the state analysis results and a preset mapping table; and the execution drive module converts the target quantity into a motor control signal.

[0029] During system operation, the state analysis module compares the vehicle speed signal with a preset threshold. When the speed is below the threshold or when a stationary turning speed of zero is detected and the steering angle changes, a low-speed range signal is output; otherwise, a high-speed range signal is output. The target calculation module generates a first control signal based on the low-speed range signal, driving the eccentric sleeve 9 to rotate to a first angular position, causing the central shaft 7 to shift backward relative to the steering axis of the front fork 2, reducing drag torque and steering resistance. Based on the high-speed range signal, a second control signal is generated, driving the eccentric sleeve 9 to rotate to a second angular position, causing the central shaft 7 to shift forward, increasing drag torque and self-centering torque.

[0030] The drive module uses a PID algorithm or fuzzy control algorithm to calculate the deviation between the actual position and the target position, and generates a PWM signal to control the drive motor 8. In the reset logic, the preload direction of the elastic energy storage component is configured to always push the eccentric sleeve 9 to rotate towards the second angular position with the largest drag torque. During normal operation, the drive motor 8 overcomes the preload and road resistance to maintain the target position; when the system determines the high-speed range, the motor drive direction is consistent with the preload direction; when the system determines the low-speed range, the motor outputs a reverse torque to overcome the preload and maintain a low drag torque state.

[0031] Please see the appendix Figure 1 - Appendix Figure 5 The reset assembly includes a normally closed electromagnetic clutch 13, which is located at the output end of the drive motor 8. A gas spring 4 is mounted on the outside of the bottom shaft 7. The normally closed electromagnetic clutch 13 is used to automatically switch to the disengaged state when the dynamic drag torque control monitoring system is powered off or malfunctions. A bushing 17 is mounted on the outside of the bottom shaft 7, and an oil seal 14 is mounted on the outside of the bushing 17. A disc brake disc 6 is mounted on the outside of the wheel hub 15, and the disc brake disc 6 is coaxially mounted with the bottom shaft 7. A speed sensor coil 16 is mounted on the side of the wheel hub 15, and the speed sensor coil 16 is coaxially mounted with the bottom shaft 7. A mudguard 3 is mounted on the outside of the tire 1, and the mudguard 3 is fixedly connected to the outside of the front fork arm 2. A front shock absorber 5 is mounted on the outside of the front fork arm 2, and the bottom end of the front shock absorber 5 is located between the gas spring 4 and the front fork arm 2.

[0032] The internal structure of the normally closed electromagnetic clutch 13 includes a stator coil assembly, an armature assembly, and a friction plate assembly made of ferromagnetic material. Under normal conditions, i.e., when the coil is not energized, the return spring inside the clutch releases the clamping force, forcing the friction plates to engage tightly with the armature, establishing a power transmission channel. At this time, the rotating shaft of the drive motor 8 and the worm gear 12 are rigidly connected, enabling torque transmission. In the control logic of this system, the normally closed electromagnetic clutch 13 is configured in a reverse operating mode of energized disengagement and de-energized engagement, or more preferably, a safe logic mode of energized engagement and de-energized disengagement is adopted, i.e., normally open, but described as normally closed in this context. When power is off, the clutch disengages, disconnecting the motor from the worm gear 12. Specifically, when the dynamic drag torque control monitoring system is operating normally, the control current is continuously applied to the clutch coil, generating electromagnetic attraction to overcome the spring force or maintain engagement, thus maintaining the linkage between the motor and the regulating mechanism. In the event of a system power outage, sensor failure, or control unit crash, the coil current is cut off, and the clutch immediately performs a mechanical disengagement action, disconnecting the constraint of the rotor inertia of the drive motor 8 on the worm 12. This causes the worm wheel 11 and worm 12 mechanism to lose its anti-torque holding capability at the input end, or directly cuts off the connection between the worm 12 and the eccentric mechanism, eliminating the effect of the self-locking effect.

[0033] The gas spring 4, which works in conjunction with the clutch, is installed between the bottom axle 7 and the fixed support point of the front fork arm 2. The gas spring 4 is an independent energy storage unit comprising a pressure cylinder and a piston rod. The cylinder is filled with high-pressure nitrogen or inert gas, and the piston rod is sealed and lubricated by oil. The installation geometry of the gas spring 4 is kinematically calculated, with its two ends hinged to the inner wall of the front fork arm 2 and the extension arm of the eccentric sleeve 9, respectively. The output characteristic curve of the gas spring 4 is set to have progressive stiffness, and its free extension length corresponds to the angle position of the bottom axle 7 at the maximum forward tilt offset, i.e., the maximum drag torque, caused by the eccentric sleeve 9. When the clutch disengages, the eccentric sleeve 9 loses the positioning torque of the motor, and the gas spring 4 releases its stored compressive potential energy, driving the eccentric sleeve 9 to rotate. Due to the presence of the gas-liquid throttling orifice inside the gas spring 4, this reset process has a damping effect, preventing the eccentric sleeve 9 from experiencing a violent impact at the moment of reset, ensuring that the steering structure smoothly returns to the highly stable mechanical limit point.

[0034] To meet the frequent rotation and load-bearing requirements of the central shaft 7 during adjustment, a bushing 17 is provided between the outer surface of the central shaft 7 and the inner bore of the eccentric sleeve 9. This bushing 17 is made of self-lubricating composite material or high-load-bearing tin bronze alloy and is press-fitted into the inner bore of the eccentric sleeve 9. The inner surface of the bushing 17 is precision honed to form a rotating fit with the outer surface of the central shaft 7. The bushing 17 is designed to withstand radial impact loads generated during vehicle operation and to provide a low-friction sliding interface, reducing driving resistance during adjustment. At the outer ends of both axial sides of the bushing 17, a skeleton oil seal 14 is provided. The main lip of the oil seal 14 is made of nitrile rubber or fluororubber, tightly fitting the journal surface of the central shaft 7, and is radially clamped by an internal annular spring. The oil seal 14 is configured with a two-way sealing structure. On the one hand, it prevents external mud, sand, moisture and corrosive liquids from entering the mating gap between the bushing 17 and the central shaft 7, thus avoiding abrasive wear. On the other hand, it seals the internally filled grease to prevent the loss of lubricating medium and ensure the maintenance-free characteristics of the adjustment mechanism throughout its entire life cycle.

[0035] The wheel hub 15 serves as the rotating base of the wheel, and a disc brake disc 6 is rigidly connected to its outer side. The disc brake disc 6 is fixed to the flange of the wheel hub 15 by multiple high-strength bolts evenly distributed, and its mounting plane is strictly perpendicular to the axis of the bottom bracket 7 to ensure that the disc runout during braking is within tolerance. The disc brake disc 6 is made of heat-resistant stainless steel or high-carbon steel, and heat dissipation holes and chip removal grooves are distributed on the disc surface. Since the position of the bottom bracket 7 in this invention is variable, the disc brake disc 6 moves relative to the front fork arm 2 along with the bottom bracket 7 and the wheel hub 15. Therefore, the brake caliper assembly that works with the disc brake disc 6, which is not detailed in the claims but is necessary, is mounted on the bottom bracket 7 or the eccentric sleeve 9 via a floating bracket to ensure that the relative position of the caliper and the brake disc is constant and does not interfere or misalign with the adjustment of the drag torque.

[0036] On the other side or the inner ring of the same side of the wheel hub 15, a speed sensing coil 16 is coaxially arranged. This sensing coil is composed of a ferromagnetic toothed ring or a multi-pole magnetized magnetic ring, with several signal trigger feature points evenly distributed on its circumference. The speed sensing coil 16 rotates synchronously with the wheel at high speed, working in conjunction with a wheel speed sensor probe fixed to a relatively stationary component such as the bottom end of the front fork arm 2 or the bearing housing. A small air gap is maintained between the two. When the sensing coil rotates, it periodically changes the magnetic field strength at the probe, thereby inducing a continuous pulse signal. The frequency of this signal is directly proportional to the wheel speed, providing high-precision speed feedback data for the control system.

[0037] The front fork arm 2 is covered by a mudguard 3, which is fixed to the non-moving part of the front fork arm 2 by a bracket or is movably connected to the bottom axle 7 by a linkage mechanism. The inner contour radius of curvature of the mudguard 3 is slightly larger than the outer radius of the tire 1, forming a protective cavity. Considering the adjustment stroke of the bottom axle 7, the installation position of the mudguard 3 is reserved with sufficient longitudinal margin, or its coverage area covers the motion envelope of the tire 1 at the maximum and minimum drag torque positions, to prevent the tire 1 from interfering with the inner wall of the mudguard 3 during adjustment.

[0038] The front fork arm 2 integrates suspension functionality, with a front shock absorber 5 externally mounted on it. The front shock absorber 5 employs a telescopic sleeve structure combining hydraulic damping and a coil spring. Its upper end connects to the frame's steering column, while the lower end sleeve forms the main body of the front fork arm 2. Structurally, the bottom mounting base of the front shock absorber 5 is located near the connection area between the gas spring 4 and the main body of the front fork arm 2. This layout allows the thrust application point of the gas spring 4 to utilize the rigid support of the shock absorber structure, while the telescopic movement of the shock absorber does not affect the relative position control of the gas spring 4 on the eccentric sleeve 9. The front shock absorber 5 is responsible for absorbing vertical vibrations caused by road surface unevenness, maintaining tire 1's contact with the ground, while the eccentric adjustment mechanism focuses on adjusting the horizontal geometric parameters. The two are mechanically independent but physically nested.

[0039] Working principle: When the drag torque needs to be adjusted, the dynamic drag torque control and monitoring system sends a command to the drive motor 8. The drive motor 8 outputs torque, which, through the meshing transmission of the worm gear 12 and worm wheel 11, drives the planetary gear 10 and the eccentric sleeve 9, which are fixedly connected to the worm wheel 11, to rotate synchronously. Due to the geometric characteristics of the eccentric sleeve 9, its rotational motion causes the central shaft 7 passing through the inside of the sleeve to be displaced in the horizontal direction. This displacement directly changes the vertical distance between the wheel center and the steering axis of the front fork, and thus changes the distance between the ground contact center of the tire 1 and the ground contact point of the extended steering axis according to the vehicle dynamics geometry, thereby realizing the physical adjustment of the drag torque.

[0040] The worm gear 11 and worm 12 mechanism has a mechanical self-locking characteristic, which can maintain the current geometric setting when the motor stops outputting, thereby reducing the energy consumption of the dynamic drag torque control and monitoring system.

[0041] In terms of control logic, the dynamic drag torque control and monitoring system adopts a closed-loop feedback control strategy. The data acquisition module uses wheel speed sensors and inertial measurement units to monitor the vehicle's speed, roll angle, and steering angle in real time. The state analysis module calculates the current operating condition based on the above signals, while the target calculation module determines the optimal wheel center offset based on a pre-stored mapping table.

[0042] When the vehicle is at low speed or turning in place, the dynamic drag torque control and monitoring system drives the eccentric sleeve 9 to rotate, causing the central shaft 7 to shift backward, reducing drag torque and thus lowering steering resistance and self-centering torque, improving low-speed maneuverability. When the vehicle enters high-speed cruising mode, the dynamic drag torque control and monitoring system drives the eccentric sleeve 9 to shift the central shaft 7 forward, increasing drag torque. The enhanced self-centering torque suppresses front wheel shimmy, improving straight-line driving stability. The position feedback module monitors the actual angle of the eccentric sleeve 9 in real time through an angle encoder and feeds it back to the controller, ensuring that the actuator accurately reaches the target position.

[0043] The output end of the drive motor 8 is equipped with a normally closed electromagnetic clutch 13, and a gas spring 4, which serves as an elastic energy storage component, connects the central shaft 7 and the front fork arm 2. Under normal energization, the clutch engages, and the motor torque is transmitted normally. Once the dynamic drag torque control monitoring system detects a power failure or a serious malfunction, the clutch automatically de-energizes and disengages, severing the rigid connection between the motor and the self-locking end of the worm gear 11 and worm 12 and the eccentric sleeve 9. At this time, the gas spring 4 releases its preload, forcibly pushing the eccentric sleeve 9 to rotate to a preset second angle position, ensuring that the vehicle can automatically return to a highly stable mechanical geometry state when the dynamic drag torque control monitoring system fails, preventing vehicle loss of control due to insufficient drag torque or uncertain parameters.

Claims

1. An adjustable drag torque front wheel steering structure, characterized in that, include: A fork arm (2) is provided with a tire (1) in the middle, a hub (15) is provided in the middle of the tire (1), a bottom axle (7) is provided in the middle of the hub (15), an adjustment component is provided on the outside of the bottom axle (7), and a reset component is provided on the outside of the fork arm (2). The adjustment assembly includes an eccentric sleeve (9) sleeved on the outside of the central shaft (7). A planetary gear (10) is provided on the outside of the central shaft (7). A worm gear (11) is fixedly connected to the outside of the planetary gear (10). A drive motor (8) is fixedly connected to the outside of the fork arm (2). A worm (12) is fixedly connected to the output end of the drive motor (8). The worm (12) meshes with the worm gear (11). A dynamic drag torque control and monitoring system is installed in the middle of the fork arm (2). The dynamic drag torque control and monitoring system is electrically connected to the drive motor (8).

2. The adjustable drag moment front wheel steering structure according to claim 1, characterized in that, The dynamic drag torque control and monitoring system includes: The data acquisition module is used to collect vehicle speed signals, roll angle signals, and steering angle signals in real time. The status analysis module, connected to the data acquisition module, is used to determine the current driving condition of the vehicle based on the acquired signals. The target calculation module is connected to the state analysis module and internally stores a mapping table between drag torque and driving conditions, which is used to calculate the target wheel center offset required under the current conditions. The execution drive module is connected to the target calculation module and the drive motor (8) to convert the target wheel center offset into a motor pulse signal and control the drive motor (8) to rotate to a specified position.

3. The adjustable drag moment front wheel steering structure according to claim 2, characterized in that, The data acquisition module includes a wheel speed sensor and an inertial measurement unit. The wheel speed sensor is located on the tire (1) or the axle (7), and the inertial measurement unit is located on the fork arm (2) or the frame. The dynamic drag torque control and monitoring system also includes a position feedback module. The output of the position feedback module is connected to the input of the execution drive module. The position feedback module includes an angle encoder, which is coaxially connected to the shaft of the drive motor (8).

4. The adjustable drag moment front wheel steering structure according to claim 2, characterized in that, The target computing module is configured to execute the following control logic: When the state analysis module outputs a low-speed range signal, the target calculation module outputs a first control signal. The first control signal corresponds to driving the eccentric sleeve (9) to rotate to a first angle position. At the first angle position, the central shaft (7) is offset backward relative to the steering axis of the front fork arm (2). When the state analysis module outputs a high-speed interval signal, the target calculation module outputs a second control signal. The second control signal corresponds to driving the eccentric sleeve (9) to rotate to a second angle position. At the second angle position, the central shaft (7) shifts forward relative to the steering axis of the fork arm (2). The reset component is an elastic energy storage component, which is connected between the eccentric sleeve (9) and the fork arm (2). The preload direction of the elastic energy storage component is configured to push the eccentric sleeve (9) to the second angle position.

5. The adjustable drag moment front wheel steering structure according to claim 1, characterized in that, The reset assembly includes a normally closed electromagnetic clutch (13), which is located at the output end of the drive motor (8). A gas spring (4) is provided outside the central shaft (7). The normally closed electromagnetic clutch (13) is used to automatically switch to the disengaged state when the dynamic drag torque control monitoring system is powered off or malfunctions.

6. The adjustable drag moment front wheel steering structure according to claim 1, characterized in that, The central shaft (7) is provided with a bushing (17) on the outside, and an oil seal (14) is provided on the outside of the bushing (17).

7. The adjustable drag moment front wheel steering structure according to claim 1, characterized in that, The wheel hub (15) is provided with a disc brake disc (6) on its outside, and the disc brake disc (6) is coaxially arranged with the central axle (7).

8. The adjustable drag moment front wheel steering structure according to claim 7, characterized in that, A speed sensing coil (16) is provided on the side of the hub (15), and the speed sensing coil (16) is coaxially arranged with the central shaft (7).

9. The adjustable drag moment front wheel steering structure according to claim 1, characterized in that, The tire (1) is provided with a mudguard (3) on its outside, and the mudguard (3) is fixedly connected to the outside of the front fork arm (2).

10. The adjustable drag moment front wheel steering structure according to claim 5, characterized in that, A front shock absorber (5) is provided on the outside of the front fork arm (2), and the bottom end of the front shock absorber (5) is located between the gas spring (4) and the front fork arm (2).

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