Cable Steering Assembly with Shaped Cams for Riding Mowers
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Solution Overview
Problem
Riding lawn mowers experience slack or play in their steering assemblies, which affects responsiveness and the overall feel of quality, particularly due to the lack of tight coupling between the steering wheel and the wheels.
Innovation Solution
A steering system utilizing a steering cable that engages shaped cams near the wheels, combined with a track bar to translate movements and eliminate slack, implementing Ackermann geometry steering to ensure both inside and outside wheels trace circles of the same radius during turns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional steering assembly is used in riding lawn mowers, then the structure is simple and easy to manufacture, but there is noticeable slack or play in the coupling between the steering wheel and the wheels which reduces responsiveness and perceived quality
Solution Approach 1:
The steering assembly is divided into multiple functional components: a steering shaft, a cable system with individual cables for each wheel, shaped cams at each wheel, and guide pulleys. This segmentation allows each component to be optimized independently for its specific function while collectively eliminating slack and improving responsiveness.
Solution Approach 2:
A cable system acts as an intermediary between the steering shaft and the wheels, replacing direct mechanical connections. The cables transmit steering forces while allowing for tension adjustment and slack elimination, providing a flexible yet responsive connection that improves steering quality.
2Ease of operation
If a steering assembly with tight coupling is implemented to eliminate slack, then steering responsiveness and perceived quality improve, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The shaped cams are designed with specific geometric parameters that allow them to convert cable tension into precise wheel rotation. By optimizing the cam profile parameters, the system achieves tight coupling and responsive steering while maintaining manufacturability through standard machining processes.
Solution Approach 2:
The cable system is designed to be self-adjusting through the shaped cams and guide pulleys, which automatically maintain proper tension and alignment during operation. This self-service characteristic reduces the need for complex adjustment mechanisms and simplifies manufacturing while ensuring consistent steering quality.
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
This solution significantly reduces or eliminates slack in the steering system, enhancing responsiveness and providing a more robust and quality-like steering experience by ensuring tight coupling between the steering wheel and the wheels, thereby improving consumer satisfaction.
Implementation Method 1
The cable may be wrapped around at least a portion of the steering shaft. The cable may terminate at respective ends thereof at corresponding ones of a first shaped cam and a second shaped cam each of which is operably coupled to respective ones of a first axle rod and a second axle rod.
Implementation Method 2
The first and second shaped cams may cause movement of the front wheels based on movement of the cable responsive to rotation of the steering shaft.
Implementation Method 3
The at least one set of guide pulleys may receive respective different portions of the cable to guide the cable to respective ones of the first and second shaped cams.
Data Source
AI summary
A riding yard maintenance vehicle may include a frame, a steering assembly, a cable and at least one set of guide pulleys. Wheels of the riding yard maintenance vehicle may be attachable to the frame. The steering assembly may include a steering apparatus operably coupled to front wheels of the riding yard maintenance vehicle via a cable system. The cable system may include the cable, which may be wrapped around at least a portion of the steering shaft. The cable may terminate at respective ends thereof at corresponding ones of a first shaped cam and a second shaped cam each of which is operably coupled to respective ones of a first axle rod and a second axle rod. The first and second axle rods may be rotatably connected to respective ones of the front wheels. The first and second shaped cams may cause movement of the front wheels based on movement of the cable responsive to rotation of the steering shaft. The at least one set of guide pulleys may receive respective different portions of the cable to guide the cable to respective ones of the first and second shaped cams.