Hydraulic Oscillation Mitigation for Working Machines
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Solution Overview
Problem
Hydraulic oscillation in rotary mixer and cold planer machines leads to unintended frame loading and stability issues when operating on uneven terrain, making it difficult to maintain a desired slope and causing operator discomfort.
Innovation Solution
A hydraulic system comprising a first and second hydraulic cylinder assembly, and a third hydraulic cylinder assembly with a flow control device and valve, which selectively couples the third hydraulic cylinder assembly to the first and second assemblies to control the flow of hydraulic fluid, limiting the extent of travel of the pistons and rods to prevent excessive oscillation and maintain stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If hydraulic cylinder assemblies are used to lift the frame on uneven terrain, then the machine can adapt to varying ground conditions and maintain cutting depth, but hydraulic oscillation occurs causing unintended frame loading and stability issues
Solution Approach 1:
A flow control device is introduced as an intermediary element between the hydraulic pump and the hydraulic cylinder assemblies. This device mediates the hydraulic fluid flow to dampen oscillations while maintaining the system's ability to adapt to terrain variations. The flow control device acts as a buffer that allows necessary frame movement for terrain adaptation while preventing excessive oscillations that cause instability.
Solution Approach 2:
The system changes the flow parameters of hydraulic fluid through the flow control device, specifically controlling the rate and direction of fluid flow between cylinders. By adjusting flow parameters rather than restricting movement entirely, the system maintains adaptability to uneven terrain while reducing oscillation amplitude to acceptable levels, thereby preserving frame stability.
2Ease of operation
If the hydraulic system allows free movement of pistons and rods, then the machine can respond dynamically to terrain changes, but excessive oscillation occurs causing operator discomfort and making it difficult to maintain desired slope
Solution Approach 1:
The flow control device serves as an intermediary that filters out harmful oscillations while permitting necessary hydraulic fluid movement for terrain adaptation. It selectively restricts flow during oscillatory conditions while maintaining flow during legitimate terrain-response movements, thereby improving operator comfort without sacrificing machine responsiveness.
Solution Approach 2:
The flow control device creates a feedback mechanism where hydraulic fluid must pass through a restricted pathway that responds to pressure changes caused by oscillation. This feedback loop naturally dampens oscillations by opposing rapid pressure changes, reducing harmful vibrations that affect operator comfort while maintaining system responsiveness to genuine terrain variations.
3Reliability
If hydraulic fluid flows freely between cylinder assemblies, then the system can balance loads dynamically, but oscillation causes unintended frame loading that makes it difficult to maintain desired cut characteristics
Solution Approach 1:
The flow control device changes the flow parameters of hydraulic fluid, converting uncontrolled free flow into controlled restricted flow. This parameter change allows the system to maintain load balancing capabilities while preventing the excessive force variations that cause unintended frame loading and cutting depth variations, thereby improving reliability of cut characteristics.
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 system effectively limits piston and rod travel, reducing unintended frame loading and enhancing machine stability, allowing for smoother operation on uneven surfaces and maintaining a desired cut characteristics.
Implementation Method 1
The third hydraulic cylinder assembly can be configured to control a flow of a hydraulic fluid between the first hydraulic cylinder assembly and the second hydraulic cylinder assembly
Data Source
AI summary
A hydraulic system for controlling a hydraulic circuit of a working machine is disclosed. The hydraulic system can include a first hydraulic cylinder assembly, a second hydraulic cylinder assembly, a third hydraulic cylinder assembly and a valve. When coupled to the first hydraulic cylinder assembly and the second hydraulic cylinder assembly, the third hydraulic cylinder assembly can be configured to control a flow of a hydraulic fluid between the first hydraulic cylinder assembly and the second hydraulic cylinder assembly to limit an extent of travel of the first piston and an extent of travel of the second piston.