Rear Axle Inclination Adjustment for Heavy Vehicle Curve Stability
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Solution Overview
Problem
Heavy vehicles experience dynamic instability issues such as oversteering and understeering due to imbalances in wheel moments and axle geometry, particularly during curve maneuvers, which are exacerbated by varying load conditions and high load values.
Innovation Solution
An adjustment system for the longitudinal inclination of the rear axle, utilizing hydraulic actuators and an eccentric element to vary the axle's inclination within a predefined angular interval based on the steering angle, reducing the axlebase and improving stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the rear axle inclination is kept fixed, then the vehicle structure is simple, but the vehicle experiences oversteering and understeering during curve maneuvers
Solution Approach 1:
The patent applies the dynamics principle by making the rear axle inclination adjustable rather than fixed. The adjustment system allows the rear axle to change its longitudinal inclination dynamically based on steering conditions, transforming a static structural parameter into a dynamic one that adapts to driving conditions to prevent oversteering and understeering
Solution Approach 2:
The patent changes the structural parameter of rear axle longitudinal inclination from a fixed value to a variable parameter. By adjusting this geometric parameter in response to steering angle changes, the system optimizes vehicle stability during curve maneuvers while managing the complexity through a controlled adjustment mechanism
2Reliability
If the rear axle inclination is adjusted to improve stability, then the vehicle's dynamic stability improves, but the device complexity increases
Solution Approach 1:
The system adjusts the rear axle longitudinal inclination parameter based on steering angle feedback, changing this geometric parameter to optimize vehicle stability and safety during curve maneuvers
Solution Approach 2:
The adjustment system incorporates feedback by monitoring the steering angle of the front wheels and using this information to automatically adjust the rear axle inclination, creating a closed-loop control system that enhances reliability while managing complexity through automated response
3Stability of the object's composition
If the axlebase is reduced through inclination adjustment, then the vehicle stability improves, but the adjustment mechanism complexity increases
Solution Approach 1:
The patent employs hydraulic actuators to adjust the rear axle inclination, using hydraulic principles to achieve precise and controlled changes in axle position. This allows for smooth, programmable adjustment of the longitudinal inclination to optimize stability while managing the complexity through mature hydraulic technology
4Reliability
If the rear wheels are steered to compensate for oversteering, then the vehicle stability improves, but the steering system complexity increases
Solution Approach 1:
The system dynamically adjusts the rear axle inclination in response to steering conditions, creating a dynamic geometric compensation mechanism that mimics the effect of active rear wheel steering without requiring complex steering linkages and actuators for the rear wheels
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively mitigates oversteering and understeering by adjusting the rear axle inclination proportionally to the front wheels' steering, enhancing the vehicle's dynamic stability and safety.
Implementation Method 1
at least one hydraulic actuator (28) configured to move the eccentric element (25)
Implementation Method 2
an eccentric element (25) operationally interposed between the first ends of the leaf spring (16, 23) and configured to push these first ends forward or backwards along the longitudinal axis A so as to vary the inclination of the axle (3)
Data Source
Figure 1~2
Figure 3A~3B
Figure 4A~4B
AI summary
A heavy vehicle (1) comprising a frame (4) extending along a longitudinal axis of the vehicle (1) and at least one front axle assembly (2) and a rear axle assembly (3) connected to the frame (4) by means of a respective suspension system (9) and provided with respective wheels (5), the vehicle comprising an adjustment system (8) configured to vary the inclination (γ) of the rear axle group (3) with respect to the longitudinal axis as a function of the steering angle of the front axle group (2).