Dual-Accumulator Hydraulic Cylinder Control for Lower Pressure Loss
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Solution Overview
Problem
In construction machines like hydraulic excavators, the bottom pressure of the boom cylinder varies with the operation of front implements, leading to high pressure loss when hydraulic fluid is supplied from an accumulator, potentially wasting accumulated energy.
Innovation Solution
A construction machine with a hydraulic cylinder, two accumulators of different set pressures, and control valves that connect the accumulators to the hydraulic cylinder based on pressure conditions to minimize pressure loss during fluid supply, allowing efficient driving by selecting the appropriate accumulator to match the hydraulic cylinder's pressure needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single accumulator with fixed set pressure is used to supply hydraulic fluid to the boom cylinder, then the accumulator structure is simple, but high pressure loss occurs when the boom cylinder bottom pressure is low, reducing energy efficiency
Solution Approach 1:
The single accumulator is divided into two separate accumulators with different set pressures (first accumulator with first set pressure, second accumulator with second set pressure). Each accumulator serves a specific pressure range, allowing the system to select the appropriate accumulator based on the boom cylinder's pressure needs, thereby reducing pressure loss and improving energy efficiency.
Solution Approach 2:
The system dynamically switches between the first and second accumulators based on the bottom pressure of the boom cylinder. The control unit opens the appropriate control valve (first or second) to connect the corresponding accumulator to the boom cylinder, making the accumulator selection adaptive to varying pressure conditions rather than using a fixed single-accumulator configuration.
2Use of energy by moving object
If the bottom pressure of the boom cylinder is low, then energy accumulation in the accumulator is reduced, but using a single accumulator with fixed pressure causes high pressure loss when supplying hydraulic fluid
Solution Approach 1:
Different accumulators are assigned different set pressures tailored to specific operational conditions. The first accumulator with lower set pressure is optimized for low-pressure operations, while the second accumulator with higher set pressure is optimized for high-pressure operations. This local optimization ensures that each accumulator operates in its most efficient pressure range, minimizing pressure loss while maintaining effective energy accumulation.
Solution Approach 2:
The system changes the pressure parameter by selecting different accumulators with different set pressures based on the operational conditions. When the boom cylinder bottom pressure is low, the first accumulator with lower set pressure is selected; when the pressure is high, the second accumulator with higher set pressure is selected. This parameter adaptation resolves the contradiction between energy accumulation and pressure 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
This configuration enables efficient driving of the hydraulic cylinder by suppressing pressure loss when hydraulic fluid is supplied from the accumulators, ensuring effective energy use and reduced fuel costs.
Implementation Method 1
a first accumulator that accumulates return fluid from the hydraulic cylinder with a first set pressure
Implementation Method 2
a second accumulator that accumulates return fluid from the hydraulic actuator with a second set pressure, the second set pressure being set to a value higher than that of the first set pressure
Implementation Method 3
a first control valve placed in a first hydraulic line that connects the first accumulator and the hydraulic cylinder to each other, and a second control valve placed in a second hydraulic line that connects the second accumulator and the hydraulic cylinder to each other
Implementation Method 4
a first hydraulic pump that delivers the hydraulic fluid sucked from the tank, a hydraulic actuator that is driven by the first hydraulic pump
Data Source
AI summary
The object of the present invention resides in provision of a construction machine in which a hydraulic cylinder can be driven in a high efficiency by an accumulator. To this end, the construction machine including: a hydraulic cylinder; a first accumulator that accumulates return fluid from the hydraulic cylinder with a first set pressure; a tank that stores hydraulic fluid therein; a first hydraulic pump that delivers the hydraulic fluid sucked from the tank; a hydraulic actuator that is driven by the first hydraulic pump; and a second accumulator that accumulates return fluid from the hydraulic actuator with a second set pressure, includes a first control valve placed in a first hydraulic line that connects the first accumulator and the hydraulic cylinder to each other, and a second control valve placed in a second hydraulic line that connects the second accumulator and the hydraulic cylinder to each other. The second set pressure is set to a value higher than that of the first set pressure.