Offset Tandem Axle Suspension for Agricultural Chassis
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Solution Overview
Problem
Towed agricultural machines with tandem chassis experience undesirable axle load shifts and uneven soil compaction due to braking torque imbalances, leading to tire wear and uneven tillage performance.
Innovation Solution
A chassis design with offset and movably suspended axles, where braking forces are introduced through a special strut system that prevents axle load shifts, using a four-link or parallelogram linkage to absorb braking torque directly into the frame, eliminating rearing or buckling effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If service brakes are equipped on tandem chassis with very short axle swings, then braking performance is improved, but the chassis tends to swing up or lower due to different braking forces on front or rear wheel
Solution Approach 1:
A support strut is introduced as an intermediary element between the braked wheel and the fixed frame. This strut absorbs and counteracts the braking forces, preventing them from causing chassis swing. The mediator (support strut) transfers the braking load directly to the frame, isolating the chassis from destabilizing forces while maintaining effective braking performance.
2Force
If only one of the two wheels of a tandem suspension is braked, then braking forces are reduced, but different loads on the wheels lead to uneven introduction of forces into the frame construction and different wheel wear
Solution Approach 1:
The support strut is specifically applied to the braked wheel location, providing localized reinforcement and force absorption. This local quality approach allows one wheel to be braked while the support strut ensures that the braking forces are evenly distributed to the frame, preventing uneven force introduction and maintaining uniform wheel loads despite asymmetric braking configuration.
3Power
If braking surface acts on the running surface of the wheels, then braking effect is achieved, but high tire wear and susceptibility to dirt occur
Solution Approach 1:
The support strut serves as a mechanical intermediary that decouples the braking action from the tire contact patch. By providing a separate force transmission path from the braked wheel to the frame, the strut allows braking forces to be applied without direct degradation of the tire running surface, reducing wear and dirt susceptibility while maintaining braking power.
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
A chassis (10) of a towed or semi-mounted agricultural machine (12) attached to an agricultural tractor is disclosed, the chassis having several pneumatic packer and/or support wheels (16), wherein at least two running wheels (16) arranged side by side and offset from each other in the direction of travel (28) are held and/or movably mounted as a pair of running wheels (20) on a machine frame (22, 24, 44) via a common suspension. The respective pair of running wheels (20) is mounted on an axle swing arm (42) pivotally mounted on the machine frame (22, 24, 44), which has a defined pivotability relative to the machine frame (22, 24, 44). At least one wheel (16) of each pair of wheels (20) has a separate braking device (46) which is supported on a suspension section (44) of the suspension or of the machine frame (22, 24).