Axial Piston Pump with Integrated Electromagnetic Motor

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Solution Overview

Problem

Conventional axial piston pumps used in aeroengine fuel control systems are heavy, axially long, and sub-optimal for integration with fuel supply systems, requiring a rotational drive shaft that can lead to leakage and complexity.

Innovation Solution

An axial piston pump driven by an electro-magnetic motor with fixed-field members integrated into the piston housing, eliminating non-rotating components and allowing 'wet' internal electro-magnetic elements, which reduces weight, axial length, and complexity, and controls pump pressure through motor speed rather than a swashplate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If an auxiliary shaft connected to the drive shaft is used to provide rotational movement, then the pump can be driven mechanically, but the pump becomes heavy and axially long with increased complexity

Engineering Contradiction:
Improvemechanical drive capabilityVSAvoidstructural complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent merges the drive shaft with the piston housing by making the piston housing itself rotatable about the axis of rotation. This eliminates the need for a separate auxiliary shaft and its associated bearings, directly reducing structural complexity and axial length while maintaining the mechanical drive capability through direct coupling to the engine drive shaft.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The piston housing is given multiple functions: it serves as both the containment structure for the pistons and as the rotatable drive element. This multi-functionality eliminates the need for separate drive components, reducing overall device complexity and weight while maintaining effective power transmission.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Power

If a rotational drive shaft is used, then mechanical power can be transmitted, but leakage occurs around the shaft

Engineering Contradiction:
Improvepower transmissionVSAvoidsealing reliability
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The invention extracts and eliminates the rotational drive shaft from the system by making the piston housing itself rotatable. This removes the source of leakage (the shaft penetrating the pump housing) while maintaining power transmission capability through direct engagement of the rotatable piston housing with the drive shaft.

Inventive Principle:
Principle #2Taking out (Extraction)

3Stress or pressure

If an adjustable swashplate is used to vary pump pressure, then pressure control is achieved mechanically, but the pump becomes more complex

Engineering Contradiction:
Improvepump pressure controlVSAvoidmechanical adjustment mechanism
Core Design Contradiction:
Stress or pressureVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical swashplate adjustment mechanism with electrical speed control of the rotatable piston housing. By controlling the rotational speed of the piston housing via the electro-magnetic motor, pump pressure is varied proportionally, eliminating complex mechanical adjustment mechanisms while maintaining effective pressure control.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Weight of moving object

If fixed-field members are integrated into the piston housing, then weight and axial length are reduced, but the electro-magnetic motor complexity increases

Engineering Contradiction:
Improvepump weightVSAvoidelectro-magnetic integration
Core Design Contradiction:
Weight of moving objectVSDevice complexity

Solution Approach 1:

The patent combines the fixed-field members of the electro-magnetic motor with the piston housing, making the piston housing itself the rotor assembly. This integration eliminates separate magnetic components and reduces overall weight, while the electro-magnetic motor complexity is managed through this unified structure rather than adding separate components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The piston housing serves multiple functions: it contains the pistons, provides the rotatable drive element, and houses the fixed-field members of the electro-magnetic motor. This multi-functionality reduces the need for separate components, thereby reducing weight and axial length while managing system complexity through integration.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3244063B1Axial piston pump
Publication Date: 2019.10.09 ROLLS ROYCE PLC
  • EP3244063B1 patent drawingFigure 1
  • EP3244063B1 patent drawingFigure 2
  • EP3244063B1 patent drawingFigure 3

AI summary

An axial piston pump is provided. The pump has a fluid inlet, and a fluid outlet. The pump further has a rotatable, one-piece piston housing carrying one or more pistons movable within one or more respective sleeves formed by the housing. A circumferential row of fixed field members is mounted to the housing at a mounting location formed by the housing, the mounting location being radially outward of the sleeve(s). The pump further has a stator surrounding the piston housing and including a circumferential row of armature windings such that the piston housing and the stator form an electro-magnetic motor operable to rotate the piston housing. The pump further has a swashplate engaged with the piston(s) such that rotation of the piston housing relative to the swash plate around an axis of rotation produces reciprocating movement of the piston(s) for the pressurisation of fluid received into the sleeve(s) from the fluid inlet and then discharged from the sleeve(s) to the fluid outlet.