Variable-Displacement Vane Pump End Stop for Low Dead Volume

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Solution Overview

Problem

Existing vane pumps face challenges in efficiently adjusting delivery rate independently of rotor drive speed and optimizing structural design for improved efficiency and acoustic behavior.

Innovation Solution

A vane pump design featuring a rotor and stator that are displaceable relative to each other, with vanes radially adjustable on the rotor's base body, forming pressure chambers and utilizing an end stop mechanism through direct or indirect contact between the stator and rotor to minimize dead volume and friction, allowing for adjustable delivery rate and fail-safe operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the stator and rotor are made displaceable relative to each other for adjustable delivery rate, then the delivery rate can be adjusted independently of rotor speed, but the structural complexity increases

Engineering Contradiction:
Improvedelivery rate adjustmentVSAvoidstructural complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The end stop function is merged directly into the rotor-stator contact interface. The rotor itself forms the end stop for the stator through direct contact, eliminating the need for separate end stop components. This integration achieves the desired delivery rate adjustment capability while minimizing structural complexity by using the existing moving parts to fulfill multiple functions.

Inventive Principle:
Principle #5Merging (Combining)

2Volume of stationary object

If direct contact between stator and rotor is used to form end stop, then dead volume is minimized, but friction losses increase

Engineering Contradiction:
Improvedead volumeVSAvoidfriction losses
Core Design Contradiction:
Volume of stationary objectVSLoss of energy

Solution Approach 1:

The system transitions from static to dynamic end stop formation. The end stop contact between stator and rotor is not fixed but dynamically adjusts based on operational requirements. This dynamic configuration allows the system to minimize dead volume when needed while managing friction losses through controlled contact conditions, optimizing both parameters across different operating states.

Inventive Principle:
Principle #15Dynamics

3Productivity

If the vanes are radially displaceable on the rotor base body, then pressure chambers are effectively formed, but manufacturing precision requirements increase

Engineering Contradiction:
Improvepumping efficiencyVSAvoidvane displacement precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The vanes on the rotor base body are designed to self-align and self-regulate their radial displacement through the pumping action itself. The pressure differential generated during operation automatically positions the vanes to form effective pressure chambers without requiring high-precision manufacturing tolerances. This self-service mechanism reduces manufacturing precision requirements while maintaining pumping efficiency.

Inventive Principle:
Principle #25Self-service

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 independent adjustment of delivery rate from rotor speed, minimizes dead volume, and enhances operational efficiency and acoustic behavior, ensuring reliable performance and reduced friction losses.

Implementation Method 1

The size of these pressure chambers initially increases during one revolution of the rotor, thereby creating a vacuum that draws in lubricant through a suitably positioned inlet channel

Methodology Applied
Scientific EffectVacuum: Vacuum

Implementation Method 2

and then decreases again, creating a positive pressure that delivers the lubricant to the component to be lubricated

Methodology Applied
Scientific EffectPositive pressure: Pressure Increase

Implementation Method 3

an end stop for the relative displacement of the rotor and the stator is formed by a (direct) contact of the stator with the rotor

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3635224B1Vane pump, fluid system, and internal combustion engine
Publication Date: 2022.12.21 VOLKSWAGEN AG
  • EP3635224B1 patent drawingFigure 1
  • EP3635224B1 patent drawingFigure 2
  • EP3635224B1 patent drawingFigure 3~4

AI summary

A vane pump (12) comprises a stator (16) and rotor (18), wherein the rotor (18) and the stator (16) are movable relative to one another in order for the delivery capacity of the vane pump (12) to be adjustable independently of a drive speed of the rotor (18). The rotor (18) comprises a main body (22) and a plurality of vanes (24), which are arranged in a manner distributed over the circumference of the main body (22) and which are held on the main body (22) so as to be movable in a radial direction relative to an axis of rotation (26) of the rotor (18). An end stop for the relative movability of the rotor (18) and of the stator (16) is formed by contact of the stator (16) with the rotor (18). Here, in particular, direct contact or indirect contact of the stator (16) with the main body (22) of the rotor (18), occurring with interpositioning of at least one of the vanes (24), can be provided. A vane pump (12) of this kind can be advantageous in respect of the structural design, the degree of efficacy, and/or the acoustic operating behaviour.