Moldboard Support Structure for Milling Machine
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Solution Overview
Problem
Milling machines face inefficiencies in clearing milled road surfaces of debris and aggregate, leading to poor bonding between new asphalt and the milled surface, and existing scraper blades introduce bending forces due to limited degrees of freedom of movement.
Innovation Solution
A milling machine with a moldboard support structure featuring a hydraulic cylinder, dual-trunnion assembly, and a spherical bearing that allows the moldboard to pivot and move freely, enabling two degrees of freedom and reducing bending forces, coupled with a safety latch for secure positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed scraper blade is used to clear milled material, then the blade structure is simple, but the blade introduces bending forces and cannot adapt to road surface contours
Solution Approach 1:
The moldboard is transformed from a fixed structure to a dynamic one with two degrees of freedom: vertical movement via hydraulic cylinder and horizontal pivoting via dual-trunnion assembly. This allows the moldboard to adapt to varying road surface contours while maintaining structural integrity by distributing forces through multiple movement axes rather than creating bending moments in a fixed structure.
Solution Approach 2:
The moldboard support structure adds dimensional freedom by enabling movement in both vertical (hydraulic cylinder) and horizontal (trunnion pivoting) dimensions. This two-dimensional mobility allows the moldboard to follow complex three-dimensional road surface contours that a single-axis or fixed structure cannot accommodate.
2Force
If a scraper blade with limited movement is used, then the structure is simpler, but bending forces are introduced on the piston cylinder unit
Solution Approach 1:
The dual-trunnion assembly provides rotational freedom that allows the hydraulic cylinder to pivot with the moldboard's movement, converting bending forces into rotational motion. This dynamic adaptation eliminates problematic bending moments while maintaining full adaptability to road surface variations.
Solution Approach 2:
The dual-trunnion assembly acts as an intermediary mechanism between the hydraulic cylinder and the moldboard, mediating the forces and movements. It transforms the linear force from the hydraulic cylinder into controlled pivoting motion, eliminating direct bending forces on the cylinder while enabling comprehensive moldboard movement.
3Productivity
If debris is not cleared from the milled surface, then the milling process is faster, but bonding between new asphalt and milled surface is poor
Solution Approach 1:
The moldboard performs preliminary cleaning action by scraping and redirecting milled material away from the freshly milled surface during the milling process itself. This preliminary removal of debris ensures that when new asphalt is applied, the surface is already clean and ready for optimal bonding, eliminating the need for separate cleaning operations.
Solution Approach 2:
The moldboard system provides self-service cleaning functionality by using the milling machine's own movement and the moldboard's scraping action to remove and redirect debris. The system serves its own cleaning needs through the integrated moldboard structure that continuously sweeps milled material off the surface during operation.
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 enables efficient removal of debris, ensures a clean milled surface, and allows the moldboard to accurately follow the road surface contours, reducing strain on the support structure and improving the bonding of new asphalt.
Implementation Method 1
The bearing may further include at least one cylindrical end portion engaging at least one projection of the moldboard. When the piston rod is coupled to the at least one projection, there may be a gap between the coupling portion of the piston rod and the at least one projection such that the coupling portion is pivotable around at least a portion of the spherical portion of the bearing.
Implementation Method 2
The dual-trunnion assembly may include a first cradle mount and a second cradle mount. The second cradle mount may include two cradle pins configured to be received within and pivot relative to the first cradle mount in a first direction, and the piston barrel may include two piston pins configured to be received within and pivot relative to the second cradle mount in a second direction different from the first direction.
Data Source
AI summary
A milling machine includes a frame, a ground engaging rotor assembly, a moldboard, and a hydraulic cylinder including a piston rod and a piston barrel. The ground engaging rotor assembly is at least partially enclosed by the moldboard. The moldboard is vertically movable via the hydraulic cylinder, and the hydraulic cylinder is coupled to the frame via a dual-trunnion assembly.