Fuel Pump Motor Stator Segmented Passage Design

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Solution Overview

Problem

Existing fuel pumps with brushless motors face a trade-off between achieving sufficient fuel delivery quantity and maintaining magnetic efficiency, as increasing the fuel passage cross-sectional area reduces magnetic force, while reducing the gap increases flow resistance, making it difficult to achieve both high efficiency and required fuel delivery in compact designs.

Innovation Solution

A fuel pump design with a stator core having six magnetic steel plates and a rotor with eight magnetic poles, using dielectric resin to create clearances between teeth for increased passage area without reducing magnetic force, and employing a concentrated winding technique to minimize coil size and maximize space factor, allowing for efficient fuel flow through the motor arrangement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the gap between stator and rotor is increased to create sufficient passage cross-sectional area for fuel flow, then fuel delivery quantity is improved, but magnetic force between rotor and stator is reduced, worsening motor efficiency

Engineering Contradiction:
Improvefuel delivery quantityVSAvoidmotor efficiency
Core Design Contradiction:
Quantity of substanceVSLoss of energy

Solution Approach 1:

The fuel passage is segmented into two distinct paths: the gap between stator and rotor for fuel flow, and clearances formed between circumferentially adjacent teeth on the rotor side for additional fuel passage. This segmentation allows sufficient fuel delivery area without increasing the gap size that would reduce magnetic force.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of increasing the radial gap dimension, the invention utilizes the circumferential dimension by forming clearances between adjacent teeth. This dimensional shift provides additional passage area without compromising the magnetic coupling between stator and rotor.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Loss of energy

If the gap between stator and rotor is reduced to increase magnetic force, then motor efficiency is improved, but passage cross-sectional area is reduced, increasing flow resistance and worsening fuel delivery

Engineering Contradiction:
Improvemotor efficiencyVSAvoidfuel delivery quantity
Core Design Contradiction:
Loss of energyVSProductivity

Solution Approach 1:

The fuel passage is segmented into two distinct paths: the gap between stator and rotor for fuel flow, and clearances formed between circumferentially adjacent teeth on the rotor side for additional fuel passage. This segmentation allows sufficient fuel delivery area without increasing the gap size that would reduce magnetic force.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The clearance between teeth provides localized additional passage area specifically in regions where it does not interfere with the magnetic field. This local quality enhancement allows increased fuel flow capacity without uniformly increasing the gap that would reduce magnetic force throughout.

Inventive Principle:
Principle #3Local quality

3Device complexity

If coils are exposed to fuel for compact design, then device complexity is reduced, but coil reliability deteriorates due to fuel contact

Engineering Contradiction:
Improvestructure simplicityVSAvoidcoil reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

Dielectric resin is used as an intermediary material that provides electrical insulation and fuel resistance between the coils and the fuel environment. This allows the coils to be positioned closer to the fuel passage without direct contact, maintaining both compact design and coil reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 the required fuel delivery quantity with minimized passage flow resistance and maintains magnetic efficiency, even with potential rotor swelling from fuel degradation, while allowing for a compact and efficient fuel pump suitable for small motorcycles.

Implementation Method 1

A bobbin, which is made of dielectric resin, is fitted to each core. Dielectric resin is filled between each circumferentially adjacent two teeth to cover each coil. Furthermore, the dielectric resin is molded to form clearances, each of which is formed between the corresponding circumferentially adjacent two teeth on a rotor side.

Methodology Applied
Scientific EffectDielectric: Dielectric

Implementation Method 2

a brushless motor to form a motor arrangement that drives a pump arrangement... In the brushless motor, there is no disadvantageous loss caused by a sliding resistance between a commutator and brushes

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

A stator core of a motor arrangement includes six cores, which are arranged one after another in a circumferential direction... A rotor with eight magnetic poles

Methodology Applied
Scientific EffectMagnetism: Magnetism

Data Source

PatentEP1783878B1Fuel pump having motor arrangement and pump arrangement
Publication Date: 2018.06.13 DENSO CORP
  • EP1783878B1 patent drawingFigure 1A~1B
  • EP1783878B1 patent drawingFigure 2
  • EP1783878B1 patent drawingFigure 3

AI summary

A stator core (30) of a motor arrangement (13) includes six cores (32), which are arranged one after another in a circumferential direction. A bobbin (40), which is made of dielectric resin, is fitted to each core (32). Each coil (42) is formed such that a winding is wound around the bobbin (40) through a concentrated winding technique. Dielectric resin (46) is filled between each circumferentially adjacent two teeth (33) to cover each coil (42). Furthermore, the dielectric resin (46) is molded to form clearances (204), each of which is formed between the corresponding circumferentially adjacent two teeth (33) on a rotor (50) side. Fuel, which is pressurized by a pump arrangement (12), passes an interior of the motor arrangement (13) through a fuel passage (202), which is a gap between an inner peripheral surface of the stator core (30) and an outer peripheral surface of the rotor (50), and also through the clearances (204).