Non-linear Backlash Element for Harvester Drive Train Vibration
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Solution Overview
Problem
Harvesting machine cutting units experience synchronization problems and increased wear due to non-uniform blade movement, leading to resonance and overheating in the drive train, which affects the durability and performance of the engine and other connected units.
Innovation Solution
A cutting unit with a drive train that includes a backlash-containing element with a non-linear return characteristic, limiting vibration amplitude by matching oscillation frequency with amplitude, and using a torsionally elastic element and rotational play to manage torque and reduce resonance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If an elastic vibration-damping coupling is inserted into the drive train to suppress vibrations, then vibration amplitude is reduced, but drive energy is lost and the clutch heats up, limiting service life
Solution Approach 1:
The patent changes the parameter of the coupling characteristic from linear to non-linear. The backlash-containing element with non-linear return characteristic provides different coupling stiffness at different operating conditions, allowing vibration suppression while reducing energy loss and heat generation compared to traditional elastic couplings.
2Stability of the object's composition
If the drive train starts to resonate, then the clutch has to dissipate high power loss, but this leads to overheating after a short time
Solution Approach 1:
The patent converts the potentially harmful resonance into a beneficial effect by using the non-linear return characteristic to actively limit oscillation amplitude. The frequency shift that occurs with increasing amplitude eliminates the match between excitation and natural frequencies, preventing resonance buildup and reducing power loss that would otherwise cause overheating.
3Stability of the object's composition
If a non-linear return characteristic is used to limit vibration amplitude, then oscillation frequency varies with amplitude, but this requires a backlash-containing element with specific mechanical properties
Solution Approach 1:
The patent introduces a backlash-containing element as an intermediary component in the drive train. This element, positioned between the drive shaft and the blade, provides the non-linear return characteristic needed for vibration control without requiring fundamental changes to the entire drive train structure.
4Stability of the object's composition
If the first section has negligible restoring torque to allow blade overshoot, then driving reaction is suppressed, but the blade movement is delayed by friction and crop cutting
Solution Approach 1:
The patent applies dynamic principles by creating a drive train system where the restoring torque is not constant but varies with the state of the system. The non-linear return characteristic allows the system to adapt between different operational phases: allowing overshoot during acceleration and providing restoration during deceleration, thereby suppressing driving reaction while minimizing time loss.
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 reduces vibration amplitude and torque fluctuations, enhancing the durability of the drive train and synchronizing the blade movement, thereby minimizing wear and overheating, and ensuring smooth operation of the harvesting machine.
Implementation Method 1
The non-linearity of the reset characteristic causes the frequency of any oscillation in the drive train to vary with its amplitude
Implementation Method 2
An external excitation can therefore only drive an oscillation of the drive train as long as the frequencies of both match. The frequency shift that occurs with increasing amplitude eliminates the match
Implementation Method 3
An external excitation can therefore only drive an oscillation of the drive train as long as the frequencies of both match
Implementation Method 4
the increase in the restoring torque with the deflection in second section is significantly larger than in the first section
Implementation Method 5
The leading knife movement can be delayed by friction of the knife in a guide on the carrier frame
Data Source
Figure 1~2
Figure 3~4
Figure 5~10
AI summary
The cutting device has carrier frameworks (1,2,3) and a blade (5) movable in the carrier frameworks. The drive strands (9,10,11,13,14) have a rotary play halting element (34) and a nonlinear rear adjusting head line. An eccentric unit (15) is provided for converting rotation of the drive strands in oscillating motion of the blade.