Hydraulic Circuit Pump Discharge Control
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Solution Overview
Problem
In hydraulic circuits for construction machines, the discharge rates of two pumps are often controlled in association, leading to inefficiencies and energy wastage when excess discharge oil is recycled, as the reduction in discharge rate of one pump is not properly managed, resulting in unnecessary energy consumption.
Innovation Solution
A hydraulic circuit design that includes a negative control pressure sensing unit and regulator to control the discharge rates of both pumps in association, with a recycling passage and sensing pressure rising passages to facilitate the reduction of the second pump's discharge rate when excess oil is present, utilizing directional control valves to manage oil flow and pressure recycling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the discharge rates of the first pump and second pump are controlled in association with each other, then the system coordination is improved, but the discharge rate of the second pump cannot be properly reduced when it has excess discharge oil, leading to energy waste
Solution Approach 1:
The invention separates the control of the two pumps by providing individual unload passages for each pump, with independent pressure sensing units and sensing pressure rising passages. This segmentation allows the second pump's discharge rate to be independently reduced when it has excess discharge oil, while the first pump continues to operate normally. The regulatory units for each pump can now be controlled independently based on their respective unload passage pressures, resolving the contradiction between system coordination and energy efficiency.
2Adaptability or versatility
If pressure oil recycling is conducted using the second pump's excess discharge oil, then resource utilization is improved, but the second pump's discharge rate is not properly reduced, causing energy waste
Solution Approach 1:
The invention implements feedback control by introducing sensing pressure rising passages that detect the pressure in the unload passage of the second pump and feed this information back to its regulatory unit. When pressure oil recycling is conducted and the second pump has excess discharge oil, the sensing pressure rises, triggering the regulatory unit to reduce the second pump's discharge rate. This feedback mechanism ensures that the pump's operation is automatically adjusted based on actual system conditions, enabling both effective pressure oil recycling and energy efficiency.
3Use of energy by moving object
If the discharge rate of the second pump is reduced to match the first pump's requirements, then energy consumption is reduced, but the system loses the ability to independently manage each pump's output
Solution Approach 1:
The invention provides separate unload passages, pressure sensing units, and regulatory units for each pump, enabling independent control of each pump's discharge rate. The first pump's regulatory unit responds to pressure changes in its unload passage, while the second pump's regulatory unit responds to pressure changes in its own unload passage. This segmented control architecture allows each pump to be independently managed based on its specific operational requirements, maintaining adaptability while reducing energy consumption through individualized rate control.
Data Source
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AI summary
A recycling passage 71 is configured to perform "pressure oil recycling," in which the recycling passage 71 feeds boom discharge oil 35Fo (recycling discharge oil) discharged from a boom cylinder 23F (a recycling actuator), to the boom cylinder 23F (an actuator actuated with feeding of discharge oil from a second pump 12). A first sensing pressure rising passage 81 feeds a part of boom discharge oil 35Fo to a first unload passage 31 upstream of a first pressure sensing unit 61p when the pressure oil recycling is performed.