Road Paver Screed Hydraulic Valve Control for Thickness Consistency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Unintentional changes in the distance between the paving screed and the subsurface during the production of road surfaces lead to unevenness, particularly when starting or resuming the manufacturing process, due to hydraulic fluid compression in lifting cylinders, causing the screed to float and form bumps.
Innovation Solution
Electrically controlled valves are used to maintain a constant amount of hydraulic fluid in the lifting cylinders by closing valves during startup, preventing fluid loss and reducing hydraulic system elasticity, thus stabilizing the screed and improving paving quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the paver starts moving after the screed is lowered, then the manufacturing process begins, but the hydraulic fluid compresses causing the screed to float and form unevenness
Solution Approach 1:
The valve is closed before the paver starts moving to prevent hydraulic fluid from leaving the cylinder. This preliminary action eliminates the compressibility issue during startup, ensuring the screed maintains constant contact pressure with the road construction material from the beginning of the manufacturing process, thereby preventing floating and unevenness.
2Stability of the object's composition
If the valve is closed to prevent hydraulic fluid loss, then the screed stability improves, but the device complexity increases due to additional control mechanisms
Solution Approach 1:
The invention extracts and addresses only the critical phase (startup) where instability occurs, rather than implementing continuous complex control. A simple valve closure during startup eliminates the need for complex continuous adjustment mechanisms, achieving stability with minimal additional device complexity.
3Ease of operation
If the hydraulic system allows fluid movement for screed adjustment, then the screed can be positioned accurately, but the system elasticity causes floating during startup
Solution Approach 1:
The hydraulic control is segmented into two distinct phases: positioning phase (valve open) and manufacturing phase (valve closed). This segmentation allows the system to benefit from hydraulic flexibility during positioning while eliminating compressibility issues during actual road construction, thereby achieving both ease of operation and manufacturing precision.
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
This approach prevents the screed from floating and forming unevenness, ensuring a consistent layer thickness and enhancing the quality of the road surface by minimizing the elasticity of the hydraulic system.
Implementation Method 1
The compression of the hydraulic fluid is caused by the resistance of the road construction material on the screed, which is reflected in the lifting cylinders as a pressure increase or compression.
Implementation Method 2
When the paving screed is lowered onto the road construction material to be paved, hydraulic fluid or hydraulic oil is sucked into the cylinder sides of the lifting cylinders due to the gravity acting on the paving screed.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Road pavers (10) are used to produce road surfaces. To regulate the thickness of the road surface layer, a screed (17) is lowered or raised. Particularly at the beginning or when resuming the production process, the elasticity of the screed's hydraulics (17) can unintentionally cause unevenness in the road surface. The application provides a road paver (10) and a method for producing a road surface that improves the quality of the road surface to be produced. This is achieved by electrically controlling at least one valve (37) attached to the cylinder sides of the lifting cylinders (22) after the screed (17) has been lowered, and by closing the valves (37) to maintain a constant amount of hydraulic fluid in the cylinder sides (29) when the road paver (10) starts up.