Off-Road Vehicle Roll Angle Stop Arrangement for Suspension Control
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Solution Overview
Problem
Conventional pivotally attached rigid front axles in off-road vehicles limit travel speed and operator comfort due to simultaneous wheel movement over obstacles, requiring robust suspension arms that increase weight and cost.
Innovation Solution
A suspension system with two pairs of roll angle stops that engage the axle carriage at different positions, allowing variable roll angle oscillation and reducing the size and weight of the suspension arm, thereby minimizing load on the arm and enhancing axle movement control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a robust suspension arm is used to withstand high loads from roll angle stops, then the strength and reliability are improved, but the weight and manufacturing cost increase
Solution Approach 1:
The suspension system divides the roll angle limitation function into two separate pairs of stops: one pair between the axle and axle carriage for the first range of movement, and another pair between the axle and suspension arm for the second range of movement. This segmentation allows each component to be optimized for its specific function, reducing the overall load requirements on the suspension arm.
Solution Approach 2:
The system implements dynamic roll angle limitation where the effective roll angle stop changes based on the axle's position in its range of movement. When the axle is in the first range (closer to axle carriage), the first pair of stops is effective. When the axle is in the second range (closer to suspension arm), the second pair of stops becomes effective. This dynamic switching reduces peak loads on the suspension arm.
2Adaptability or versatility
If the axle is allowed to move freely up and down, then the suspension capability is improved, but the roll angle control becomes problematic when the axle is close to the chassis
Solution Approach 1:
The system provides dynamic roll angle control that adapts to the axle's vertical position. The transition between the first and second pairs of roll angle stops occurs at a predefined position in the suspension stroke, allowing the system to maintain appropriate roll angle limitation throughout the entire range of movement without compromising suspension capability.
Solution Approach 2:
The axle carriage acts as an intermediary element that facilitates the transition between different roll angle stop mechanisms. The first pair of stops engages with the axle carriage when the axle is in the first range of movement, providing roll angle control without directly loading the suspension arm.
3Device complexity
If conventional single pair of roll angle stops is used, then the device complexity is reduced, but the roll angle limitation is insufficient across the entire suspension stroke
Solution Approach 1:
The suspension system segments the roll angle limitation function into two distinct ranges of movement, each served by a dedicated pair of roll angle stops. This ensures reliable roll angle control throughout the entire suspension stroke while maintaining clear functional separation between the two stop mechanisms.
Solution Approach 2:
The dual pair of roll angle stops provides universal roll angle limitation coverage across the entire suspension stroke, with each pair optimized for a specific range. This multi-functional approach ensures that roll angle control is maintained regardless of the axle's vertical position.
Data Source
AI summary
An off-road vehicle includes a chassis, an axle carriage, a rigid axle and a pair of suspension cylinders. The axle carriage is attached to or forms a part of the chassis, and includes a generally vertically arranged slot. The rigid axle is mounted to the axle carriage with a wheel hub at each end thereof, and is vertically movable relative to the axle carriage. The suspension cylinders are connected between the axle carriage and axle, and are operable to move the axle in vertical directions relative to the axle carriage. The off-road vehicle is characterized in that the axle includes a first pair of roll angle stops which engage the axle carriage when the axle is at or near a fully lowered position relative to the axle carriage, and a second pair of roll angle stops which engage the axle carriage when the axle is at or near a fully raised position relative to the axle carriage.