Off-Road Suspension Layout for Long-Wheelbase Brake-Over Clearance
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Solution Overview
Problem
Conventional four-wheel off-road vehicles with long wheelbases lack sufficient ramp brake-over angles and wheel travel, leading to a higher likelihood of the vehicle bottom contacting the ground during various terrain conditions.
Innovation Solution
The vehicle design includes specific suspension configurations and wheelbase dimensions to enhance ramp brake-over angles and wheel travel, ensuring a minimum ground clearance and increased wheel travel ratios, particularly for rear and front wheels, thereby reducing the likelihood of ground contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the wheelbase is increased to provide greater stability and comfort, then the vehicle length is improved, but the ramp brake-over angle decreases and the likelihood of ground contact increases
Solution Approach 1:
The patent applies parameter changes by optimizing the suspension system characteristics (spring constants, damping coefficients) and geometric parameters (linkage lengths, pivot positions) to achieve a ramp brake-over angle of 55 degrees or more while maintaining a long wheelbase of 1340 mm or more. This resolves the contradiction by changing the system parameters to simultaneously achieve both long wheelbase and sufficient ground clearance.
2Adaptability or versatility
If the suspension travel is increased to improve terrain adaptability, then the wheel travel is improved, but the vehicle complexity increases
Solution Approach 1:
The patent applies dynamics by implementing a suspension system with sufficient wheel travel (360 mm or more on the rear wheel side) that dynamically adapts to varying terrain conditions. The suspension components are designed to provide the necessary travel range while maintaining a manageable structural complexity through careful selection of linkage configurations and component arrangements.
Data Source
AI summary
A vehicle includes a first suspension between a body and a front wheel, and a second suspension between the body and a rear wheel. An angle θ1 represents a ramp brake-over angle, and angles θ2, θ3, and θ4 respectively represent angles corresponding to the ramp brake-over angle when the first and the second suspension are fully stretched, fully compressed and fully stretched respectively, and fully stretched and fully compressed respectively. When a wheelbase is not smaller than about 1340 mm, the angle θ1 is not smaller than about 55 degrees, a value θ2/θ1 is not smaller than about 1.25, a value θ3/θ1 is not smaller than about 0.9, and a value θ4/θ1 is not smaller than about 0.8. When the wheelbase is not smaller than about 1340 mm and not greater than about 2000 mm, a wheel travel on the rear wheel side is not smaller than about 360 mm, a ratio of a stretch-side value to a compression-side value (stretch-side/compression-side) of the wheel travel on the rear wheel side is not smaller than about 0.5, and a value θ2/θ1 is not smaller than about 1.25.