Socketed Steering Column for Zero-Turn Radius Mower
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Solution Overview
Problem
Mechanical steering systems in riding lawn mowers often interfere with the ability to navigate uneven terrain, leading to unintentional turns and wheel skidding, which impede operator control and can damage lawns.
Innovation Solution
A steering system with a front wheel frame pivotally coupled to the vehicle frame about a roll axis, featuring a rack and pinion mechanism with socketed connections that allow axial movement, enabling the front wheels to roll relative to the vehicle frame while maintaining steering control, thus preventing unintentional turns and skidding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a mechanical steering system is used to control the steerable wheels, then steering control is provided, but the system interferes with the ability to travel over uneven terrain, causing unintentional turns and wheel skidding
Solution Approach 1:
The steering system is segmented into independent components: a steering column with shaft portions for steering input, and a rack and pinion mechanism with socketed connections for wheel articulation. This segmentation allows the steering function to be separated from the suspension function, enabling the front wheel frame to roll independently over uneven terrain while maintaining controlled steering through the socketed connections that permit axial movement.
Solution Approach 2:
The steering column and rack and pinion mechanism incorporate dynamic elements including socketed connections that allow axial movement along the shaft axis. This dynamic capability enables the steering system to adapt to terrain changes in real-time, preventing unintentional turns and wheel skidding while maintaining operator control through the steering wheel.
2Ease of operation
If the steering system is mechanically connected to the steerable wheels, then steering function is achieved, but wheel skidding occurs which damages lawns
Solution Approach 1:
The rack and pinion mechanism acts as an intermediary between the steering column and the steerable wheels. The socketed connections in this intermediary mechanism transmit steering input while permitting axial movement, which prevents direct mechanical binding between the steering system and the wheels during terrain transitions, thereby eliminating wheel skidding and lawn damage.
3Stability of the object's composition
If the front wheel frame is rigidly connected to the vehicle frame, then structural stability is maintained, but the ability to roll relative to the vehicle frame is prevented
Solution Approach 1:
The front wheel frame is segmented from the vehicle frame through pivotal coupling about a roll axis, allowing independent rolling motion. This segmentation enables the front wheel frame to adapt to uneven terrain by rolling relative to the vehicle frame while maintaining structural stability through the rack and pinion steering mechanism that provides controlled articulation.
Data Source
AI summary
A steering system for a riding lawn mower includes a wheel frame pivotally coupled to a vehicle frame about a roll axis. The wheel frame has spaced apart upper and lower wheel frame members. Steering knuckles are pivotally coupled to opposing sides of the wheel frame for rotatably supporting wheels. Each steering knuckle is straddle mounted between the upper and lower wheel frame members. A rack and pinion steering mechanism for pivoting the steering knuckles is coupled to a steering wheel via a steering column. The steering column includes a shaft portion extending along a shaft axis and has at least one socketed connection. The socketed connection transmits rotational movement about the shaft axis between the shaft portion and another rotatable component. The socketed connection also permits axial movement of the shaft portion along the shaft axis in response to the wheel frame rolling relative to the vehicle frame.