Inner-Outer Rotor Pump Assembly With Self-Adjusting Radial Gap

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Solution Overview

Problem

Existing pumps face challenges in achieving high efficiency and stability under high pressure while maintaining reduced weight and cost, particularly in the vehicle sector where fuel consumption and cost pressures are significant.

Innovation Solution

A pump unit design with an inner and outer rotor configuration, where the outer rotor aligns concentrically with the housing bore, reducing the radial gap through a hydrodynamic bearing condition, and utilizing a pressure gradient to generate a directed force, enhancing efficiency and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the radial gap between outer rotor and inner rotor is reduced to increase efficiency, then pumping efficiency increases, but manufacturing precision requirements worsen

Engineering Contradiction:
Improvepumping efficiencyVSAvoidform and positional tolerances
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The pump unit employs a self-regulating mechanism where the hydraulic operating principle automatically adjusts the radial gap through the spacing of the outer rotor from the reference point of the housing. The system uses its own operating fluid and pressure to maintain optimal clearance without external intervention or complex control systems.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention changes the positional parameter of the outer rotor relative to the housing reference point, creating a predetermined offset that optimizes the radial gap. This parameter adjustment allows the system to achieve smaller effective clearance while accommodating normal manufacturing tolerances.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If the radial gap is reduced to improve efficiency at high pressures, then energy efficiency increases, but device complexity increases

Engineering Contradiction:
Improveenergy efficiencyVSAvoidhousing bore geometry
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The housing bore is designed with asymmetric geometry relative to the outer rotor, creating a predetermined offset that generates a directed force. This asymmetric design produces a self-centering effect that maintains optimal radial gap without requiring additional balancing mechanisms or complex control systems.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The invention utilizes hydraulic principles where the operating fluid under pressure generates forces that act on the outer rotor. The pressure gradient between different regions of the housing bore creates a directed force that positions the outer rotor optimally, reducing radial gap through fluid pressure rather than mechanical constraints.

Inventive Principle:
Principle #29Pneumatics and hydraulics

3Productivity

If the outer rotor is positioned eccentrically to reduce radial gap, then pumping efficiency improves, but stability under high pressure worsens

Engineering Contradiction:
Improvepumping efficiencyVSAvoidperformance stability
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The system creates a self-regulating feedback mechanism where the hydraulic pressure and directed forces continuously act to maintain the optimal position of the outer rotor. Any deviation from the predetermined spacing triggers hydraulic forces that restore the optimal radial gap, ensuring stable performance under varying pressure conditions.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The invention transitions from a static clearance design to a dynamic self-adjusting system. The outer rotor position is not fixed but continuously adjusted by hydraulic forces that respond to operating conditions, allowing the system to maintain optimal radial gap dynamically during operation rather than relying on precise static manufacturing.

Inventive Principle:
Principle #15Dynamics

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 design achieves increased efficiency and stability by reducing the radial gap, allowing for higher pressure operation with improved manufacturing tolerances and cost-effectiveness.

Implementation Method 1

the outer rotor aligns concentrically with the housing bore, reducing the radial gap through a hydrodynamic bearing condition

Methodology Applied
Scientific EffectHydrodynamic bearing: Lubrication

Implementation Method 2

utilizing a pressure gradient to generate a directed force, enhancing efficiency and stability

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentEP4692549A1Pump assembly
Publication Date: 2026.02.11 THOMAS SA
  • EP4692549A1 patent drawingFigure 1
  • EP4692549A1 patent drawingFigure 2~4
  • EP4692549A1 patent drawing

AI summary

The invention relates to a pump unit (10) comprising an inner rotor (12), an outer rotor (14), and a housing (16), wherein the inner rotor (12) has a predetermined position (18) relative to the housing (16), the predetermined position (18) being configured to space a rotation axis (20) of the outer rotor (14) apart from a reference (22) of the housing (16), so that a radial gap (24) between the outer rotor (14) and the inner rotor (12) is reduced, wherein the pump unit (10) is configured to pump a fluid by rotating the inner rotor (12) and/or the outer rotor (14).