Steerable Rear Axle Keyed Coupling for Windrower Steering
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Solution Overview
Problem
Dual-path steering systems in self-propelled work machines, such as windrowers, experience control difficulties due to high turn resistance, leading to slow reaction and potential understeer or oversteer, especially at higher speeds, and in tight spaces, due to friction in the caster assembly and ground contact, making precise control challenging.
Innovation Solution
A steering assist arrangement is introduced, featuring a keyed connecting mechanism that selectively engages or disengages the steering arm with the caster spindle, allowing the caster wheel to pivot independently or be assisted by the steering cylinder, enabling improved steering response by coupling the steering arm with the engagement plate, thereby enhancing control at higher speeds and in tight spaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the caster wheels are free to pivot independently (traditional dual-path steering), then the machine maintains agility at lower speeds, but turn resistance and reaction delay increase at higher speeds
Solution Approach 1:
The steering system dynamically changes its configuration based on operating conditions. The keyed connecting mechanism allows the steering arm to be selectively coupled or decoupled from the caster spindle, transitioning the system between two distinct states: a coupled state for high-speed transport where the steering arm assists in reducing turn resistance, and an uncoupled state for low-speed field operations where the caster wheels maintain independent pivoting agility.
2Productivity
If the keyed connecting mechanism couples the steering arm with the engagement plate, then steering control is improved at higher speeds, but the system complexity increases
Solution Approach 1:
The invention extracts the steering assist function from the traditional dual-path steering system by introducing a separate, selectively engageable steering arm mechanism. This allows the steering assist functionality to be added only when needed for high-speed transport, rather than being permanently integrated into the caster assembly, thereby minimizing the impact on overall system complexity.
3Ease of operation
If the caster assembly friction is reduced for better steering response, then steering control improves, but the structural integrity and stability may be compromised
Solution Approach 1:
The steering arm acts as an intermediary mechanism between the machine's dual-path steering system and the caster wheels. Instead of modifying the caster assembly's internal friction characteristics, the steering arm provides an external assist force that helps overcome turn resistance, thereby improving steering control without compromising the structural integrity or stability of the caster assembly itself.
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 steering assist arrangement improves machine controllability at higher speeds while maintaining agility at lower speeds by reducing turn resistance and reaction delay, allowing for more precise control and versatility in operational modes.
Implementation Method 1
a steering cylinder connected to an outward end of the steering arm
Implementation Method 2
A keyed connecting mechanism selectively couples the steering arm with the engagement plate
Implementation Method 3
Turn resistance of the caster wheels results from friction in the pivot of the caster assembly and friction between the castered wheels and the ground
Data Source
AI summary
A working vehicle has a castor wheel assembly selectively providing steering assist. A pivoting caster spindle coupled with a caster wheel and an engagement plate connected to the caster spindle in a fixed manner such that the engagement plate pivots with the caster spindle. A pivoting steering arm is rotatably connected to the caster spindle and a steering cylinder is connected to an outward end of the steering arm with a tie rod configured to pivot the steering arm. A keyed connecting mechanism selectively couples the steering arm with the engagement plate. In an engaged position, the keyed connecting mechanism couples the steering arm with the engagement plate such that the steering cylinder pivots the caster spindle and caster wheel. In a disengaged position, the steering arm is uncoupled with the engagement plate such that the caster spindle and caster wheel are free to pivot independent of the steering cylinder.