Tandem Wheel Assembly with Reaction Bars for Ground Contact
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Solution Overview
Problem
Work vehicles, such as forwarders, face challenges in maintaining consistent ground contact and traction over varying terrain while supporting significant loads and operating loads, particularly during acceleration and deceleration, due to the transfer of load forces and shocks through the wheels and suspension.
Innovation Solution
A tandem wheel assembly with a center pivot cage and reaction bars is designed to provide improved downforce distribution by pivotally mounting the wheel assemblies relative to the chassis, using bushings to improve turning moment and reduce moment arms, and incorporating reaction bars to maintain wheel engagement with the ground through reactive forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If tandem wheel assemblies are used to support significant loads across multiple wheels, then load-carrying capability is improved, but maintaining consistent ground contact and traction over varying terrain becomes difficult due to load force transfer through wheels and suspension
Solution Approach 1:
The wheel assembly is divided into separate wheel ends that can pivot independently relative to the chassis. Each wheel end is mounted on a pivot axis allowing independent movement, enabling each wheel to maintain ground contact separately while supporting significant loads collectively
Solution Approach 2:
The wheel assembly transitions from a fixed rigid structure to a dynamic pivoting structure. The wheel ends are allowed to pivot relative to the chassis, creating a movable system that adapts to terrain variations while maintaining load-bearing capability
2Stability of the object's composition
If the wheel assembly is made rigid to maintain structural stability, then structural stability is improved, but the ability to adapt to varying terrain and maintain wheel ground contact is reduced
Solution Approach 1:
The rigid wheel assembly is segmented into separate wheel ends that can pivot independently. This segmentation allows each wheel end to adapt to terrain variations while the overall structure maintains stability through the pivot cage configuration
Solution Approach 2:
The system changes the degree of freedom parameter by allowing pivoting motion at the wheel ends. This parameter change enables terrain adaptation while the pivot cage and reaction bar system maintains structural stability under load
3Power
If high-ratio gear reduction is used to deliver high-torque power to wheels, then power delivery capability is improved, but device complexity increases
Solution Approach 1:
The gear reduction mechanisms at each wheel end are integrated into a unified pivot cage structure. The reaction bars connect the gear trains to the pivot cage, merging the power transmission and pivot functions into a single integrated system that reduces overall complexity
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 tandem wheel assembly effectively distributes torque between wheel ends, maintaining consistent traction and reducing the impact of bumps and terrain changes, thereby stabilizing the work implement and maintaining weight distribution during operation.
Implementation Method 1
A pair of reaction bars are included with which each reaction bar being pivotally coupled at one end to the annular body of the pivot cage and at an opposite end to a component of the wheel end gear train
Implementation Method 2
The inboard wall and the outboard wall of the tandem wheel housing is pivotally mounted to the pivot cage at, respectively, the inboard end and the outboard end of the annular body
Implementation Method 3
Each wheel end gear train is coupled for rotation by the associated wheel end sprocket and configured to effect a gear ratio change and rotate the associated wheel end hub about the associated wheel end axis
Data Source
AI summary
A tandem wheel assembly includes a tandem wheel housing having a center opening extending along a pivot axis, and wheel end openings extending along associated wheel axes. A pivot cage is configured to fixedly mount to a chassis of a vehicle and is disposed about the pivot axis at the center opening. A center sprocket is disposed within and rotatable with respect to the pivot cage. A wheel end assembly is disposed at each wheel end opening and has a wheel end sprocket, a wheel end gear train, and a wheel end hub. Each wheel end gear train is coupled for rotation by the wheel end sprocket and rotates the wheel end hub about the wheel end axis. A pair of reaction bars are pivotally coupled to the pivot cage at one end and to a component of the wheel end gear train at the other end.