Agricultural Tractor Steering System with Dual-Mode Axle Control
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Solution Overview
Problem
The SuperSteer™ steering system for agricultural tractors causes unwanted side skids during low-speed steering, leading to control issues and potential damage when operating near rows of plants or with front loaders, as the entire front axle rotates around a vertical axis, resulting in unwelcome movements of attached implements.
Innovation Solution
A steering system where wheel steering and front axle steering are initially independent until predetermined angles are reached, after which they synchronize like a traditional SuperSteer™ system, preventing side skids by maintaining conventional steering at low speeds and transitioning to SuperSteer™ for larger turns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the entire front axle rotates around a vertical axis during steering, then the turning radius is reduced and maneuverability is improved, but side skids occur causing control issues and potential damage to implements
Solution Approach 1:
The steering system is divided into two independent subsystems: wheel steering (rotating wheels around their own axes) and axle steering (rotating the front axle around a vertical pin). These subsystems operate independently until predetermined steering angles are reached, allowing the vehicle to avoid side skids during moderate steering while still achieving reduced turning radius when needed
Solution Approach 2:
The system dynamically transitions between different steering modes based on the steering angle. During moderate steering, only wheel steering is active maintaining conventional behavior. When steering angles exceed predetermined values, the system automatically engages axle steering to provide SuperSteer effect, creating a dynamic adaptation to operational conditions
2Measurement precision
If conventional steering is used at low speeds, then side skids are avoided and control precision is improved, but the turning radius remains large reducing maneuverability
Solution Approach 1:
The system changes the steering parameter (steering angle) to determine the appropriate mode. When steering angles remain below predetermined thresholds, conventional wheel steering is maintained for precision. When angles exceed thresholds, the system transitions to include axle steering, changing the fundamental steering parameter to achieve tighter turns
Data Source
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AI summary
A steering system (100) for motor vehicles (10), in particular for agricultural machines, comprising: a first conventional steering assembly (150) of the front wheels (W3, W4) to rotate only each of said front wheels (W3, W4) by a respective angle (a1), (a2). The steering system (100) further comprises: a second steering assembly (160) to steer at the same time the front axle (13) and the front wheels (W3, W4) of an angle (ß). The second steering assembly (160) is activated only after that each angle (a1), (a2) has reached a respective pre-determined value (a1*), (a2*) during the conventional steering performed by said first conventional steering assembly (150).