Hydraulic Flow Continuity via Variable Displacement Pumps
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Solution Overview
Problem
Hydraulic systems without directional control valves face flow continuity issues due to unequal areas of rod and head sides of actuators, leading to performance inefficiencies and potential interruptions in fluid flow.
Innovation Solution
A hydraulic system comprising primary and secondary bi-directional variable displacement pumps, with a controller to determine and manage flow continuity requirements, ensuring continuous fluid flow by adjusting the direction and displacement of both primary and secondary pumps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a bi-directional variable displacement pump is used to direct flow between rod and head sides of the actuator without a directional control valve, then cost and structural complexity are reduced, but flow continuity is interrupted due to unequal flow volumes
Solution Approach 1:
An accumulator is introduced as an intermediary component to mediate between the primary pump and the actuator. The accumulator stores hydraulic fluid and releases it when needed, acting as a buffer that compensates for flow volume discrepancies between rod and head sides, thereby maintaining flow continuity without requiring a directional control valve
Solution Approach 2:
The system dynamically adjusts the displacement of the bi-directional variable displacement pump based on operational requirements. By changing the pump's displacement parameter, the system optimizes flow delivery to maintain continuity while accommodating the unequal areas of rod and head sides
2Ease of operation
If a directional control valve is used to control flow to and from rod and head sides of the actuator, then flow control precision is improved, but system cost and complexity increase
Solution Approach 1:
The directional control valve is extracted (removed) from the system. Instead of using a valve to direct flow, the patent employs a bi-directional variable displacement pump that can reversibly change its displacement to control flow direction and volume, thereby achieving flow control precision without the complexity and cost of a directional control valve
Solution Approach 2:
The mechanical valve-based flow control system is replaced with a pump-based flow control system. The bi-directional variable displacement pump uses mechanical displacement adjustment to control flow, substituting the need for directional control valves and their associated complex valve mechanisms
3Device complexity
If the unequal areas of rod and head sides are not properly accommodated, then system simplicity is maintained, but flow continuity at the pump is interrupted
Solution Approach 1:
The accumulator serves as a mediator that absorbs the discrepancy caused by unequal areas. When the actuator moves in one direction, the accumulator stores or releases fluid to compensate for the volume difference, maintaining continuous flow through the pump without adding complex valve systems
Solution Approach 2:
The system employs dynamic adjustment of the variable displacement pump to adapt to the changing flow requirements caused by unequal areas. The pump's displacement is continuously adjusted based on the actuator's position and direction, ensuring flow continuity while maintaining system simplicity
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 maintains flow continuity across primary hydraulic circuits, enhancing operational efficiency and preventing interruptions, even when actuators work against varying loads and pressures.
Implementation Method 1
a bi-directional variable displacement primary pump for directing hydraulic flow between ports of the actuator
Data Source
AI summary
A hydraulic system comprises a plurality of primary hydraulic circuits and a secondary hydraulic circuit for satisfying flow continuity of the primary hydraulic circuits.