Variable Displacement Pump Radial Actuator Control

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Solution Overview

Problem

Traditional variable displacement pumps face challenges in changing displacement due to insufficient differential pressure and are affected by sudden pressure changes, limiting their effectiveness.

Innovation Solution

A variable displacement pump system incorporating a rotor with vanes and a cam ring, controlled by radial actuators and biasing members, which allow for direct control of the pumping action and are designed to operate independently of pressure changes, using electromechanical actuators to adjust the cam ring's position and alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional variable displacement pumps rely on differential pressure to change displacement, then the system is simpler, but the displacement cannot be changed if discharge pressure is too low

Engineering Contradiction:
Improvedisplacement control reliabilityVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the traditional pressure-dependent mechanical displacement control mechanism with an electromechanical actuator system. The actuator directly controls the cam ring position through mechanical actuation, eliminating the need for differential pressure to initiate displacement changes. This allows reliable displacement control across all pressure conditions, including low discharge pressure scenarios where traditional systems fail.

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

2Reliability

If conventional pumps use pressure-dependent displacement control, then the structure is simpler, but sudden pressure changes cause problems

Engineering Contradiction:
Improvepressure stabilityVSAvoidactuator control system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The electromechanical actuator provides direct mechanical control of the cam ring position, independent of system pressure fluctuations. This decoupling of displacement control from pressure-dependent mechanisms eliminates the problematic interaction between sudden pressure changes and displacement control, ensuring stable and predictable pump operation under varying pressure conditions.

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

3Manufacturing precision

If radial actuators are used to directly control cam ring position, then displacement control precision is improved, but the device becomes more complex

Engineering Contradiction:
Improvedisplacement control precisionVSAvoidactuator and biasing member system
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The cam ring serves as an intermediary mechanical element that translates the linear motion of the electromechanical actuator into the precise angular positioning required for variable displacement control. This intermediary mechanism provides precise displacement control while maintaining a relatively simple overall structure, as the cam ring geometry inherently provides the necessary motion transformation and control precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Stability of the object's composition

If biasing members are added to provide opposing force, then the cam ring positioning is more stable, but the device complexity increases

Engineering Contradiction:
Improvecam ring positioning stabilityVSAvoidbiasing member configuration
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The biasing members provide a controlled opposing force to the electromechanical actuator, creating a balanced force system that stabilizes cam ring positioning. This counterbalancing approach ensures the cam ring remains firmly positioned at the desired displacement setting, preventing drift or instability while maintaining system simplicity through the use of standard spring or hydraulic biasing elements.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

Data Source

PatentEP4467811A1Variable displacement pump systems
Publication Date: 2024.11.27 HAMILTON SUNDSTRAND CORP
  • EP4467811A1 patent drawingFigure 1
  • EP4467811A1 patent drawingFigure 2
  • EP4467811A1 patent drawingFigure 3~4

AI summary

A variable displacement pump (100) can include a rotor (101) having a plurality of vanes (105), and a cam ring (107) surrounding the rotor and vanes. The vanes can be configured to extend from the rotor and contact an inner cam surface (107a) of the cam ring. The pump can also include one or more radial actuators (109) configured to apply a radial force to the cam ring to control a position of the cam ring and the pumping action.