Variable Displacement Motor-Pump for Aerial Refueling Hose Control
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Solution Overview
Problem
Aerial refueling systems using hydraulic motor-pumps suffer from low hose retraction rates and increased weight due to accessory components, leading to higher response times and safety risks during hose engagement and disengagement.
Innovation Solution
A hydraulic motor assembly (HMA) incorporating a variable displacement motor-pump (VDMP) with a dual orifice (DO) system, which includes a fixed and variable orifice to manage hydraulic fluid flow, allowing for efficient hose extension and retraction by controlling flow rates and torque, thereby improving hose retraction rates and reducing system weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fixed displacement hydraulic motors are used to control hose extension and retraction, then the system structure is simple, but hose retraction rates are low and response time is increased
Solution Approach 1:
The patent applies a variable displacement motor-pump (VDMP) that can dynamically adjust its displacement based on operational requirements. The VDMP transitions between pump mode (for rapid hose extension) and motor mode (for controlled hose retraction), enabling the system to optimize performance for each phase of operation rather than being constrained by fixed displacement characteristics.
Solution Approach 2:
The system changes the operational parameters of the hydraulic motor by varying its displacement. The VDMP can adjust its displacement ratio to provide high flow rates during hose extension and high torque during hose retraction, thereby improving both retraction rate and response time through parameter optimization.
2Reliability
If accessory components are added to the hydraulic motor-pump system, then control precision is improved, but overall system weight increases
Solution Approach 1:
The patent merges the motor and pump functions into a single variable displacement motor-pump unit. This integration eliminates the need for separate motors, pumps, and associated accessory components, thereby maintaining control precision while reducing overall system weight and complexity.
Solution Approach 2:
The VDMP serves multiple functions: it acts as a motor during hose retraction, as a pump during hose extension, and includes integrated bypass capabilities. This multi-functionality reduces the need for separate dedicated components for each function, thereby reducing system weight while maintaining or improving control precision.
3Speed
If high flow rates are used during hose extension, then extension speed is improved, but hose tension control becomes difficult
Solution Approach 1:
The VDMP dynamically adjusts its displacement during hose extension to provide high flow rates for rapid extension while simultaneously controlling output pressure to maintain proper hose tension. The system transitions smoothly between different displacement settings to balance speed and tension control requirements.
Solution Approach 2:
The system incorporates feedback mechanisms that monitor hose tension and flow rate, allowing the VDMP to adjust its operation in real-time. This feedback control ensures that high extension speeds are achieved while maintaining appropriate hose tension levels throughout the extension process.
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 HMA enhances hose retraction rates and reduces system weight, improving safety and response times by dynamically controlling hose tension and position, minimizing the risk of aircraft accidents during refueling operations.
Implementation Method 1
A dual orifice (DO) coupled with the supply conduit and the return conduit in parallel with the VDMP, which can function as a bypass valve. The DO includes a fixed orifice, which continuously conveys hydraulic fluid from the supply conduit to the return conduit, and a variable orifice, which only conveys hydraulic fluid from the supply conduit to the return conduit when the VDMP operates in the pump mode
Data Source
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AI summary
Apparatuses and systems that use a variable displacement motor-pump (VDMP) to control the position of a hose of an aerial refueling system are disclosed. At VDMP displacements greater than required to hold a position of the hose, the VDMP operates in a motor mode to retract the hose. For lesser VDMP displacements, the VDMP operates in a pump mode to control extension of the hose. In accordance with some embodiments, a dual orifice conveys hydraulic fluid at varying rates depending upon the VDMP operational mode.