Windrower Caster Wheel Suspension with Elastomeric Torsion Spring
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Solution Overview
Problem
Windrowers with castered rear wheels face issues of a rough ride and fatigue of machine components due to increased ground speeds and loads, as well as limited ground clearance, which existing suspension systems fail to adequately address.
Innovation Solution
A suspension arrangement for windrowers featuring a torsion spring with an outer tube, inner member, and elastomeric members between them, coupled with a caster wheel assembly, providing damping and optimizing suspension characteristics while maintaining structural integrity and clearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If air bag suspension is used between frame and axle, then ride comfort is improved, but excessive motion at operator station occurs due to lack of damping
Solution Approach 1:
The suspension system combines two different damping mechanisms: viscous dampers (providing velocity-proportional damping) and elastomeric elements (providing displacement-proportional springing). This composite approach creates a viscoelastic suspension system that simultaneously improves ride comfort through energy dissipation while controlling excessive operator station motion through combined damping characteristics.
2Adaptability or versatility
If rear axle is made pivotable to accommodate uneven ground, then ground adaptation is improved, but structural fatigue increases due to horizontal and vertical loads
Solution Approach 1:
Viscous dampers are introduced as intermediary elements between the pivotable axle and the machine frame. These dampers act as mediators that control the relative motion between the adapting axle and the fixed frame, dissipating energy from horizontal and vertical loads. This reduces the transmission of load fluctuations to the axle structure and pivot points, thereby reducing fatigue while preserving ground adaptation capability.
3Adaptability or versatility
If tread width is increased to accommodate large windrows, then windrow capacity is improved, but loads on axle and pivot assembly increase
Solution Approach 1:
Viscous dampers serve as intermediary elements that control and dissipate energy from the increased loads generated by wider tread configurations. By providing velocity-proportional damping, they reduce the magnitude and frequency of load transmissions to the axle and pivot assembly, enabling wider tread widths to be used for accommodating large windrows without proportionally increasing structural loads.
4Length of stationary object
If cantilevered pivot configuration is used to increase clearance, then ground clearance is improved, but structural concerns and machine length issues arise
Solution Approach 1:
Viscous dampers are installed as intermediary components within the existing pivot assembly structure, between the axle and frame. This approach increases ground clearance by allowing greater pivot travel range while the dampers control the motion to prevent excessive or uncontrolled movement. The dampers enable clearance improvement without requiring the more complex cantilevered pivot configuration.
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 solution enhances the ride quality by damping vibrations and reducing unsprung mass, while maintaining structural integrity and increasing ground clearance, thus addressing the rough ride and fatigue concerns.
Implementation Method 1
a plurality of elastomeric members interposed between the outer tube and the inner member
Implementation Method 2
The suspension is in the form of a torsion spring including an outer tube, an inner member, and a plurality of elastomeric members interposed between the outer tube and the inner member
Data Source
AI summary
A suspension arrangement for a work machine includes a frame and a rear axle rigidly carried by and substantially immovable relative to the frame. The suspension arrangement includes a caster wheel assembly having a shaft, a wheel arm, a suspension and a caster wheel. The shaft is pivotably couplable with an outboard end of the rear axle. The caster wheel is coupled with a lower end of the wheel arm. The suspension is in the form of a torsion spring including an outer tube, an inner member, and a plurality of elastomeric members interposed between the outer tube and the inner member. The outer tube is coupled with the shaft, and the inner member is coupled with an upper end of the wheel arm.