Four Wheel Drive System With Independent Steering And Zero Turning Radius
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Solution Overview
Problem
Existing four-wheel drive vehicles face challenges in achieving zero turning radius capabilities due to complexities in driving the steering wheels, which limits their maneuverability and traction, especially in heavy equipment vehicles like tractors.
Innovation Solution
A four-wheel drive system for bilaterally symmetrical vehicles that independently rotates both front and rear wheels about horizontal and vertical axes, using hydraulic pumps or motors, with a controller to manage propulsion and steering, allowing the rear wheels to turn 360 degrees for zero turning radius capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If steering wheels are made larger for greater traction, then traction is improved, but the framework of the vehicle is interfered with
Solution Approach 1:
The patent applies asymmetry by making the front steering wheels larger than the rear drive wheels. This asymmetric wheel size configuration allows the front wheels to provide greater traction for steering maneuvers while the rear wheels maintain adequate clearance within the vehicle framework. The differential wheel sizes resolve the contradiction by optimizing each wheel's function for its specific role.
2Adaptability or versatility
If conventional differentials are used to drive steering wheels, then four wheel drive capability is achieved, but device complexity increases
Solution Approach 1:
The patent segments the drive system by using separate differential mechanisms for the front steering wheels and rear drive wheels, with independent clutch controls for each wheel. This segmentation allows each wheel to be controlled independently, enabling four-wheel drive capability while simplifying the overall system architecture compared to a single complex differential system. Each differential unit handles specific functions, reducing interdependence and complexity.
3Ease of operation
If zero turning radius is achieved through steering mechanisms, then maneuverability is improved, but traction capability deteriorates
Solution Approach 1:
The patent merges steering and propulsion functions by making the front wheels both steerable and driven. The front wheels can rotate about vertical axes for steering while simultaneously receiving driving force from the differential system. This merging of functions allows the vehicle to achieve zero turning radius through differential steering of driven wheels, maintaining full traction capability during maneuvers without sacrificing either maneuverability or traction.
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
Enables four-wheel drive vehicles to achieve zero turning radius while maintaining traction and maneuverability, improving their ability to navigate unstable ground and tight spaces.
Implementation Method 1
The drive systems comprise hydraulic pumps or motors. The second drive system includes two pumps, one for delivering a propulsion force to the rear wheels and another for delivering a steering force to the rear wheels.
Data Source
AI summary
A four wheel drive system for bilaterally symmetric vehicles is characterized by separate drive systems for the front and rear wheels. Each drive system is operable to independently drive each wheel. The rear wheels of the vehicle are steering wheels which are connected with the vehicle frame for independent rotation about a vertical axis. Steering and driving of the wheels is controlled by a controller. The combination of independent steering for the rear wheels and independent powering of all four wheels provides the vehicle with a zero turning radius for improved mobility as well as improved traction on unstable surfaces.