Asymmetric Steering Axle for Crawler Chassis
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Solution Overview
Problem
Agricultural working machines with crawler chassis face challenges in achieving large steering angles without collisions or chassis adjustments, particularly when retrofitting, due to the height and central position of crawler tracks.
Innovation Solution
Designing a steering drive axle with a larger front deflection roller diameter and a smaller rear deflection roller, allowing for a wedge-shaped contour that pivots under the chassis, combined with an Ackermann steering mechanism and an eccentrically arranged caterpillar drive, which reduces the need for clearance and enables larger steering angles while avoiding collisions. Additionally, using a hydraulic actuator to lift the rear deflection roller and adjust ground pressure for improved steering and terrain adaptation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the crawler tracks are positioned centrally on the axle with equal diameter front and rear deflection rollers, then the machine structure is simple and symmetric, but large steering angles cause collisions with the chassis
Solution Approach 1:
The patent applies asymmetry by designing the front deflection roller with a larger diameter than the rear deflection roller. This asymmetric configuration creates a wedge-shaped profile that enables the crawler track to pivot underneath the chassis during steering, allowing large steering angles without collisions with the chassis while maintaining a relatively simple structural design.
2Ease of operation
If the front deflection roller diameter is increased to enable larger steering angles, then steering clearance is improved, but the overall track height and ground clearance are reduced
Solution Approach 1:
The asymmetric design with a larger front deflection roller and smaller rear deflection roller creates a wedge-shaped profile. This allows the track to pivot underneath the chassis during steering, improving steering clearance while maintaining adequate ground clearance and overall track height for operational requirements.
3Ease of operation
If the rear deflection roller diameter is reduced to enable pivoting under the chassis, then steering angle is improved, but the track stability and ground contact area are reduced
Solution Approach 1:
The reduced diameter of the rear deflection roller compared to the front creates the necessary wedge shape for pivoting under the chassis. This asymmetric configuration enables large steering angles while the front deflection roller's larger diameter compensates for stability requirements during straight-line operation.
Data Source
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AI summary
The present invention relates to an agricultural machine (50, 60), in particular a self-propelled harvesting machine, comprising at least one tracked chassis (54) having two tracked running gears (1), which is arranged on an axle (52) of the machine (50, 60), wherein each tracked running gear (1) has a front deflection roller (2) and a rear deflection roller (3) as well as at least one intermediate support roller (4), wherein the axle (52), which accommodates the tracked running gears (1) on both sides, is designed as a steering drive axle (7), wherein the respective front deflection roller (2) pointing in the forward direction (V) has a larger diameter than the rear deflection roller (3).