Hydraulic Control Assembly for Road Finisher Screed
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Solution Overview
Problem
Conventional hydraulic control systems for screeds in road finishers face challenges in maintaining consistent paving quality due to external disturbances and require specialized skills for starting and stopping, leading to potential rework and inefficiencies.
Innovation Solution
A hydraulic control arrangement that regulates loading and relief pressures based on predetermined operating states, using proportional pressure control valves and dual flow regulators, with pressure sensors for real-time adjustments, and independently controllable hydraulic cylinders to manage asymmetrical weight distribution, ensuring even screed operation and efficient energy use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional hydraulic control systems are used for screed, then the system structure is simple, but the paving quality consistency deteriorates due to external disturbances and requires specialized operator skills
Solution Approach 1:
The patent implements feedback control by using pressure sensors to detect actual loading and relief pressures, comparing them with predetermined values, and automatically adjusting the proportional pressure control valves to maintain consistent screed contact pressure despite external disturbances during paving operations
Solution Approach 2:
The control system performs self-regulation by automatically adjusting pressures based on sensor feedback without requiring specialized operator intervention. The system monitors its own state and makes corrections autonomously, eliminating the need for highly skilled operators to maintain paving quality consistency
2Stability of the object's composition
If loading and relief pressures are regulated based on operating states, then the screed operation consistency improves, but the control arrangement complexity increases
Solution Approach 1:
The control system dynamically adjusts loading and relief pressures based on predetermined operating states such as different paving speeds. The proportional pressure control valves respond in real-time to maintain optimal screed contact pressure for each operating condition, ensuring consistent operation across varying work conditions
Solution Approach 2:
The system changes pressure parameters dynamically by regulating loading and relief pressures according to the operating state. Pressure sensors detect actual pressures and the control arrangement automatically adjusts valve positions to maintain predetermined pressure values suitable for each operating condition, ensuring stable screed performance
3Manufacturing precision
If proportional pressure control valves are used to regulate relief pressure, then the paving quality improves, but the energy loss increases
Solution Approach 1:
The control system maintains continuous regulation of relief pressure through proportional pressure control valves, ensuring that hydraulic energy is used efficiently and continuously for its intended purpose of maintaining screed contact pressure, rather than being wasted through frequent on-off cycling or excessive pressure relief
4Stability of the object's composition
If dual flow regulators are used for symmetrical loading control, then the screed leveling improves, but the device complexity increases
Solution Approach 1:
The flow control function is segmented into two separate dual flow regulators, each independently controlling one side of the screed. This segmentation allows precise independent adjustment of loading and relieving flows on each side, ensuring symmetrical leveling while keeping each regulator's design relatively simple and manageable
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 enhances paving quality by maintaining consistent screed operation despite external influences, reduces rework, and improves operational efficiency by allowing precise control of pressures and volume flows, ensuring symmetrical loading and unloading even with asymmetrical weight distribution.
Implementation Method 1
the relief pressure supplied to the actuating cylinder on the piston rod side being regulated in an operating state 'control of the screed load' via a proportional pressure control valve
Implementation Method 2
the hydraulic control arrangement includes a pressure sensor which is designed to detect the pressure on the piston rod or piston side, with the loading pressure or relief pressure being controlled as a function of the detected pressure
Implementation Method 3
The provision of the double current regulator enables the screed to be raised and lowered evenly
Data Source
AI summary
The arrangement (1) has consumer connections (7, 8) for pressurizing a piston (2a) of a double-acting actuation cylinder (2) with load pressure or relief pressure. A pressure regulating valve (15) i.e. proportional valve, regulates the relief pressure, which is applied to the actuation cylinder. The load- or relief pressure is controllable based on a traveling speed of a road finisher. Hydraulic oil is pushing out from a piston side of the actuation cylinder and is supplied to a tank connection (6) through directional valves (11, 13).